/******************************************************************************
 *
 * Project:  CPL - Common Portability Library
 * Purpose:  Convenience functions.
 * Author:   Frank Warmerdam, warmerdam@pobox.com
 *
 ******************************************************************************
 * Copyright (c) 1998, Frank Warmerdam
 * Copyright (c) 2007-2014, Even Rouault <even dot rouault at spatialys.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

#include "cpl_config.h"

#if defined(HAVE_USELOCALE) && !defined(__FreeBSD__)
// For uselocale, define _XOPEN_SOURCE = 700
// and OpenBSD with libcxx 19.1.7 requires 800 for vasprintf
// (cf https://github.com/OSGeo/gdal/issues/12619)
// (not sure if the following is still up to date...) but on Solaris, we don't
// have uselocale and we cannot have std=c++11 with _XOPEN_SOURCE != 600
#if defined(__sun__) && __cplusplus >= 201103L
#if _XOPEN_SOURCE != 600
#ifdef _XOPEN_SOURCE
#undef _XOPEN_SOURCE
#endif
#define _XOPEN_SOURCE 600
#endif
#else
#ifdef _XOPEN_SOURCE
#undef _XOPEN_SOURCE
#endif
#define _XOPEN_SOURCE 800
#endif
#endif

// For atoll (at least for NetBSD)
#ifndef _ISOC99_SOURCE
#define _ISOC99_SOURCE
#endif

#ifdef MSVC_USE_VLD
#include <vld.h>
#endif

#include "cpl_conv.h"

#include <algorithm>
#include <atomic>
#include <cctype>
#include <cerrno>
#include <climits>
#include <clocale>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <mutex>
#include <set>

#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_XLOCALE_H
#include <xlocale.h>  // for LC_NUMERIC_MASK on MacOS
#endif

#include <sys/types.h>  // open

#if defined(__FreeBSD__)
#include <sys/user.h>  // must be after sys/types.h
#include <sys/sysctl.h>
#endif

#include <sys/stat.h>  // open
#include <fcntl.h>     // open, fcntl

#ifdef _WIN32
#include <io.h>  // _isatty, _wopen
#else
#include <unistd.h>  // isatty, fcntl
#if HAVE_GETRLIMIT
#include <sys/resource.h>  // getrlimit
#include <sys/time.h>      // getrlimit
#endif
#endif

#include <string>

#if __cplusplus >= 202002L
#include <bit>  // For std::endian
#endif

#include "cpl_config.h"
#include "cpl_multiproc.h"
#include "cpl_string.h"
#include "cpl_vsi.h"
#include "cpl_vsil_curl_priv.h"
#include "cpl_known_config_options.h"

#ifdef DEBUG
#define OGRAPISPY_ENABLED
#endif
#ifdef OGRAPISPY_ENABLED
// Keep in sync with ograpispy.cpp
void OGRAPISPYCPLSetConfigOption(const char *, const char *);
void OGRAPISPYCPLSetThreadLocalConfigOption(const char *, const char *);
#endif

// Uncomment to get list of options that have been fetched and set.
// #define DEBUG_CONFIG_OPTIONS

static CPLMutex *hConfigMutex = nullptr;
static volatile char **g_papszConfigOptions = nullptr;
static bool gbIgnoreEnvVariables =
    false;  // if true, only take into account configuration options set through
            // configuration file or
            // CPLSetConfigOption()/CPLSetThreadLocalConfigOption()

static std::vector<std::pair<CPLSetConfigOptionSubscriber, void *>>
    gSetConfigOptionSubscribers{};

// Used by CPLOpenShared() and friends.
static CPLMutex *hSharedFileMutex = nullptr;
static int nSharedFileCount = 0;
static CPLSharedFileInfo *pasSharedFileList = nullptr;

// Used by CPLsetlocale().
static CPLMutex *hSetLocaleMutex = nullptr;

// Note: ideally this should be added in CPLSharedFileInfo*
// but CPLSharedFileInfo is exposed in the API, hence that trick
// to hide this detail.
typedef struct
{
    GIntBig nPID;  // pid of opening thread.
} CPLSharedFileInfoExtra;

static volatile CPLSharedFileInfoExtra *pasSharedFileListExtra = nullptr;

/************************************************************************/
/*                             CPLCalloc()                              */
/************************************************************************/

/**
 * Safe version of calloc().
 *
 * This function is like the C library calloc(), but raises a CE_Fatal
 * error with CPLError() if it fails to allocate the desired memory.  It
 * should be used for small memory allocations that are unlikely to fail
 * and for which the application is unwilling to test for out of memory
 * conditions.  It uses VSICalloc() to get the memory, so any hooking of
 * VSICalloc() will apply to CPLCalloc() as well.  CPLFree() or VSIFree()
 * can be used free memory allocated by CPLCalloc().
 *
 * @param nCount number of objects to allocate.
 * @param nSize size (in bytes) of object to allocate.
 * @return pointer to newly allocated memory, only NULL if nSize * nCount is
 * NULL.
 */

void *CPLCalloc(size_t nCount, size_t nSize)

{
    if (nSize * nCount == 0)
        return nullptr;

    void *pReturn = CPLMalloc(nCount * nSize);
    memset(pReturn, 0, nCount * nSize);
    return pReturn;
}

/************************************************************************/
/*                             CPLMalloc()                              */
/************************************************************************/

/**
 * Safe version of malloc().
 *
 * This function is like the C library malloc(), but raises a CE_Fatal
 * error with CPLError() if it fails to allocate the desired memory.  It
 * should be used for small memory allocations that are unlikely to fail
 * and for which the application is unwilling to test for out of memory
 * conditions.  It uses VSIMalloc() to get the memory, so any hooking of
 * VSIMalloc() will apply to CPLMalloc() as well.  CPLFree() or VSIFree()
 * can be used free memory allocated by CPLMalloc().
 *
 * @param nSize size (in bytes) of memory block to allocate.
 * @return pointer to newly allocated memory, only NULL if nSize is zero.
 */

void *CPLMalloc(size_t nSize)

{
    if (nSize == 0)
        return nullptr;

    if ((nSize >> (8 * sizeof(nSize) - 1)) != 0)
    {
        // coverity[dead_error_begin]
        CPLError(CE_Failure, CPLE_AppDefined,
                 "CPLMalloc(%ld): Silly size requested.",
                 static_cast<long>(nSize));
        return nullptr;
    }

    void *pReturn = VSIMalloc(nSize);
    if (pReturn == nullptr)
    {
        if (nSize < 2000)
        {
            CPLEmergencyError("CPLMalloc(): Out of memory allocating a small "
                              "number of bytes.");
        }

        CPLError(CE_Fatal, CPLE_OutOfMemory,
                 "CPLMalloc(): Out of memory allocating %ld bytes.",
                 static_cast<long>(nSize));
    }

    return pReturn;
}

/************************************************************************/
/*                             CPLRealloc()                             */
/************************************************************************/

/**
 * Safe version of realloc().
 *
 * This function is like the C library realloc(), but raises a CE_Fatal
 * error with CPLError() if it fails to allocate the desired memory.  It
 * should be used for small memory allocations that are unlikely to fail
 * and for which the application is unwilling to test for out of memory
 * conditions.  It uses VSIRealloc() to get the memory, so any hooking of
 * VSIRealloc() will apply to CPLRealloc() as well.  CPLFree() or VSIFree()
 * can be used free memory allocated by CPLRealloc().
 *
 * It is also safe to pass NULL in as the existing memory block for
 * CPLRealloc(), in which case it uses VSIMalloc() to allocate a new block.
 *
 * @param pData existing memory block which should be copied to the new block.
 * @param nNewSize new size (in bytes) of memory block to allocate.
 * @return pointer to allocated memory, only NULL if nNewSize is zero.
 */

void *CPLRealloc(void *pData, size_t nNewSize)

{
    if (nNewSize == 0)
    {
        VSIFree(pData);
        return nullptr;
    }

    if ((nNewSize >> (8 * sizeof(nNewSize) - 1)) != 0)
    {
        // coverity[dead_error_begin]
        CPLError(CE_Failure, CPLE_AppDefined,
                 "CPLRealloc(%ld): Silly size requested.",
                 static_cast<long>(nNewSize));
        return nullptr;
    }

    void *pReturn = nullptr;

    if (pData == nullptr)
        pReturn = VSIMalloc(nNewSize);
    else
        pReturn = VSIRealloc(pData, nNewSize);

    if (pReturn == nullptr)
    {
        if (nNewSize < 2000)
        {
            char szSmallMsg[80] = {};

            snprintf(szSmallMsg, sizeof(szSmallMsg),
                     "CPLRealloc(): Out of memory allocating %ld bytes.",
                     static_cast<long>(nNewSize));
            CPLEmergencyError(szSmallMsg);
        }
        else
        {
            CPLError(CE_Fatal, CPLE_OutOfMemory,
                     "CPLRealloc(): Out of memory allocating %ld bytes.",
                     static_cast<long>(nNewSize));
        }
    }

    return pReturn;
}

/************************************************************************/
/*                             CPLStrdup()                              */
/************************************************************************/

/**
 * Safe version of strdup() function.
 *
 * This function is similar to the C library strdup() function, but if
 * the memory allocation fails it will issue a CE_Fatal error with
 * CPLError() instead of returning NULL. Memory
 * allocated with CPLStrdup() can be freed with CPLFree() or VSIFree().
 *
 * It is also safe to pass a NULL string into CPLStrdup().  CPLStrdup()
 * will allocate and return a zero length string (as opposed to a NULL
 * string).
 *
 * @param pszString input string to be duplicated.  May be NULL.
 * @return pointer to a newly allocated copy of the string.  Free with
 * CPLFree() or VSIFree().
 */

char *CPLStrdup(const char *pszString)

{
    if (pszString == nullptr)
        pszString = "";

    const size_t nLen = strlen(pszString);
    char *pszReturn = static_cast<char *>(CPLMalloc(nLen + 1));
    memcpy(pszReturn, pszString, nLen + 1);
    return (pszReturn);
}

/************************************************************************/
/*                             CPLStrlwr()                              */
/************************************************************************/

/**
 * Convert each characters of the string to lower case.
 *
 * For example, "ABcdE" will be converted to "abcde".
 * Starting with GDAL 3.9, this function is no longer locale dependent.
 *
 * @param pszString input string to be converted.
 * @return pointer to the same string, pszString.
 */

char *CPLStrlwr(char *pszString)

{
    if (pszString == nullptr)
        return nullptr;

    char *pszTemp = pszString;

    while (*pszTemp)
    {
        *pszTemp =
            static_cast<char>(CPLTolower(static_cast<unsigned char>(*pszTemp)));
        pszTemp++;
    }

    return pszString;
}

/************************************************************************/
/*                              CPLFGets()                              */
/*                                                                      */
/*      Note: LF = \n = ASCII 10                                        */
/*            CR = \r = ASCII 13                                        */
/************************************************************************/

// ASCII characters.
constexpr char knLF = 10;
constexpr char knCR = 13;

/**
 * Reads in at most one less than nBufferSize characters from the fp
 * stream and stores them into the buffer pointed to by pszBuffer.
 * Reading stops after an EOF or a newline. If a newline is read, it
 * is _not_ stored into the buffer. A '\\0' is stored after the last
 * character in the buffer. All three types of newline terminators
 * recognized by the CPLFGets(): single '\\r' and '\\n' and '\\r\\n'
 * combination.
 *
 * @param pszBuffer pointer to the targeting character buffer.
 * @param nBufferSize maximum size of the string to read (not including
 * terminating '\\0').
 * @param fp file pointer to read from.
 * @return pointer to the pszBuffer containing a string read
 * from the file or NULL if the error or end of file was encountered.
 */

char *CPLFGets(char *pszBuffer, int nBufferSize, FILE *fp)

{
    if (nBufferSize == 0 || pszBuffer == nullptr || fp == nullptr)
        return nullptr;

    /* -------------------------------------------------------------------- */
    /*      Let the OS level call read what it things is one line.  This    */
    /*      will include the newline.  On windows, if the file happens      */
    /*      to be in text mode, the CRLF will have been converted to        */
    /*      just the newline (LF).  If it is in binary mode it may well     */
    /*      have both.                                                      */
    /* -------------------------------------------------------------------- */
    const long nOriginalOffset = VSIFTell(fp);
    if (VSIFGets(pszBuffer, nBufferSize, fp) == nullptr)
        return nullptr;

    int nActuallyRead = static_cast<int>(strlen(pszBuffer));
    if (nActuallyRead == 0)
        return nullptr;

    /* -------------------------------------------------------------------- */
    /*      If we found \r and out buffer is full, it is possible there     */
    /*      is also a pending \n.  Check for it.                            */
    /* -------------------------------------------------------------------- */
    if (nBufferSize == nActuallyRead + 1 &&
        pszBuffer[nActuallyRead - 1] == knCR)
    {
        const int chCheck = fgetc(fp);
        if (chCheck != knLF)
        {
            // unget the character.
            if (VSIFSeek(fp, nOriginalOffset + nActuallyRead, SEEK_SET) == -1)
            {
                CPLError(CE_Failure, CPLE_FileIO,
                         "Unable to unget a character");
            }
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Trim off \n, \r or \r\n if it appears at the end.  We don't     */
    /*      need to do any "seeking" since we want the newline eaten.       */
    /* -------------------------------------------------------------------- */
    if (nActuallyRead > 1 && pszBuffer[nActuallyRead - 1] == knLF &&
        pszBuffer[nActuallyRead - 2] == knCR)
    {
        pszBuffer[nActuallyRead - 2] = '\0';
    }
    else if (pszBuffer[nActuallyRead - 1] == knLF ||
             pszBuffer[nActuallyRead - 1] == knCR)
    {
        pszBuffer[nActuallyRead - 1] = '\0';
    }

    /* -------------------------------------------------------------------- */
    /*      Search within the string for a \r (MacOS convention             */
    /*      apparently), and if we find it we need to trim the string,      */
    /*      and seek back.                                                  */
    /* -------------------------------------------------------------------- */
    char *pszExtraNewline = strchr(pszBuffer, knCR);

    if (pszExtraNewline != nullptr)
    {
        nActuallyRead = static_cast<int>(pszExtraNewline - pszBuffer + 1);

        *pszExtraNewline = '\0';
        if (VSIFSeek(fp, nOriginalOffset + nActuallyRead - 1, SEEK_SET) != 0)
            return nullptr;

        // This hackery is necessary to try and find our correct
        // spot on win32 systems with text mode line translation going
        // on.  Sometimes the fseek back overshoots, but it doesn't
        // "realize it" till a character has been read. Try to read till
        // we get to the right spot and get our CR.
        int chCheck = fgetc(fp);
        while ((chCheck != knCR && chCheck != EOF) ||
               VSIFTell(fp) < nOriginalOffset + nActuallyRead)
        {
            static bool bWarned = false;

            if (!bWarned)
            {
                bWarned = true;
                CPLDebug("CPL",
                         "CPLFGets() correcting for DOS text mode translation "
                         "seek problem.");
            }
            chCheck = fgetc(fp);
        }
    }

    return pszBuffer;
}

/************************************************************************/
/*                         CPLReadLineBuffer()                          */
/*                                                                      */
/*      Fetch readline buffer, and ensure it is the desired size,       */
/*      reallocating if needed.  Manages TLS (thread local storage)     */
/*      issues for the buffer.                                          */
/*      We use a special trick to track the actual size of the buffer   */
/*      The first 4 bytes are reserved to store it as a int, hence the  */
/*      -4 / +4 hacks with the size and pointer.                        */
/************************************************************************/
static char *CPLReadLineBuffer(int nRequiredSize)

{

    /* -------------------------------------------------------------------- */
    /*      A required size of -1 means the buffer should be freed.         */
    /* -------------------------------------------------------------------- */
    if (nRequiredSize == -1)
    {
        int bMemoryError = FALSE;
        void *pRet = CPLGetTLSEx(CTLS_RLBUFFERINFO, &bMemoryError);
        if (pRet != nullptr)
        {
            CPLFree(pRet);
            CPLSetTLS(CTLS_RLBUFFERINFO, nullptr, FALSE);
        }
        return nullptr;
    }

    /* -------------------------------------------------------------------- */
    /*      If the buffer doesn't exist yet, create it.                     */
    /* -------------------------------------------------------------------- */
    int bMemoryError = FALSE;
    GUInt32 *pnAlloc =
        static_cast<GUInt32 *>(CPLGetTLSEx(CTLS_RLBUFFERINFO, &bMemoryError));
    if (bMemoryError)
        return nullptr;

    if (pnAlloc == nullptr)
    {
        pnAlloc = static_cast<GUInt32 *>(VSI_MALLOC_VERBOSE(200));
        if (pnAlloc == nullptr)
            return nullptr;
        *pnAlloc = 196;
        CPLSetTLS(CTLS_RLBUFFERINFO, pnAlloc, TRUE);
    }

    /* -------------------------------------------------------------------- */
    /*      If it is too small, grow it bigger.                             */
    /* -------------------------------------------------------------------- */
    if (static_cast<int>(*pnAlloc) - 1 < nRequiredSize)
    {
        const int nNewSize = nRequiredSize + 4 + 500;
        if (nNewSize <= 0)
        {
            VSIFree(pnAlloc);
            CPLSetTLS(CTLS_RLBUFFERINFO, nullptr, FALSE);
            CPLError(CE_Failure, CPLE_OutOfMemory,
                     "CPLReadLineBuffer(): Trying to allocate more than "
                     "2 GB.");
            return nullptr;
        }

        GUInt32 *pnAllocNew =
            static_cast<GUInt32 *>(VSI_REALLOC_VERBOSE(pnAlloc, nNewSize));
        if (pnAllocNew == nullptr)
        {
            VSIFree(pnAlloc);
            CPLSetTLS(CTLS_RLBUFFERINFO, nullptr, FALSE);
            return nullptr;
        }
        pnAlloc = pnAllocNew;

        *pnAlloc = nNewSize - 4;
        CPLSetTLS(CTLS_RLBUFFERINFO, pnAlloc, TRUE);
    }

    return reinterpret_cast<char *>(pnAlloc + 1);
}

/************************************************************************/
/*                            CPLReadLine()                             */
/************************************************************************/

/**
 * Simplified line reading from text file.
 *
 * Read a line of text from the given file handle, taking care
 * to capture CR and/or LF and strip off ... equivalent of
 * DKReadLine().  Pointer to an internal buffer is returned.
 * The application shouldn't free it, or depend on its value
 * past the next call to CPLReadLine().
 *
 * Note that CPLReadLine() uses VSIFGets(), so any hooking of VSI file
 * services should apply to CPLReadLine() as well.
 *
 * CPLReadLine() maintains an internal buffer, which will appear as a
 * single block memory leak in some circumstances.  CPLReadLine() may
 * be called with a NULL FILE * at any time to free this working buffer.
 *
 * @param fp file pointer opened with VSIFOpen().
 *
 * @return pointer to an internal buffer containing a line of text read
 * from the file or NULL if the end of file was encountered.
 */

const char *CPLReadLine(FILE *fp)

{
    /* -------------------------------------------------------------------- */
    /*      Cleanup case.                                                   */
    /* -------------------------------------------------------------------- */
    if (fp == nullptr)
    {
        CPLReadLineBuffer(-1);
        return nullptr;
    }

    /* -------------------------------------------------------------------- */
    /*      Loop reading chunks of the line till we get to the end of       */
    /*      the line.                                                       */
    /* -------------------------------------------------------------------- */
    size_t nBytesReadThisTime = 0;
    char *pszRLBuffer = nullptr;
    size_t nReadSoFar = 0;

    do
    {
        /* --------------------------------------------------------------------
         */
        /*      Grow the working buffer if we have it nearly full.  Fail out */
        /*      of read line if we can't reallocate it big enough (for */
        /*      instance for a _very large_ file with no newlines). */
        /* --------------------------------------------------------------------
         */
        if (nReadSoFar > 100 * 1024 * 1024)
            // It is dubious that we need to read a line longer than 100 MB.
            return nullptr;
        pszRLBuffer = CPLReadLineBuffer(static_cast<int>(nReadSoFar) + 129);
        if (pszRLBuffer == nullptr)
            return nullptr;

        /* --------------------------------------------------------------------
         */
        /*      Do the actual read. */
        /* --------------------------------------------------------------------
         */
        if (CPLFGets(pszRLBuffer + nReadSoFar, 128, fp) == nullptr &&
            nReadSoFar == 0)
            return nullptr;

        nBytesReadThisTime = strlen(pszRLBuffer + nReadSoFar);
        nReadSoFar += nBytesReadThisTime;
    } while (nBytesReadThisTime >= 127 && pszRLBuffer[nReadSoFar - 1] != knCR &&
             pszRLBuffer[nReadSoFar - 1] != knLF);

    return pszRLBuffer;
}

/************************************************************************/
/*                            CPLReadLineL()                            */
/************************************************************************/

/**
 * Simplified line reading from text file.
 *
 * Similar to CPLReadLine(), but reading from a large file API handle.
 *
 * @param fp file pointer opened with VSIFOpenL().
 *
 * @return pointer to an internal buffer containing a line of text read
 * from the file or NULL if the end of file was encountered.
 */

const char *CPLReadLineL(VSILFILE *fp)
{
    return CPLReadLine2L(fp, -1, nullptr);
}

/************************************************************************/
/*                           CPLReadLine2L()                            */
/************************************************************************/

/**
 * Simplified line reading from text file.
 *
 * Similar to CPLReadLine(), but reading from a large file API handle.
 *
 * @param fp file pointer opened with VSIFOpenL().
 * @param nMaxCars  maximum number of characters allowed, or -1 for no limit.
 * @param papszOptions NULL-terminated array of options. Unused for now.

 * @return pointer to an internal buffer containing a line of text read
 * from the file or NULL if the end of file was encountered or the maximum
 * number of characters allowed reached.
 *
 */

const char *CPLReadLine2L(VSILFILE *fp, int nMaxCars,
                          CPL_UNUSED CSLConstList papszOptions)

{
    int nBufLength;
    return CPLReadLine3L(fp, nMaxCars, &nBufLength, papszOptions);
}

/************************************************************************/
/*                           CPLReadLine3L()                            */
/************************************************************************/

/**
 * Simplified line reading from text file.
 *
 * Similar to CPLReadLine(), but reading from a large file API handle.
 *
 * @param fp file pointer opened with VSIFOpenL().
 * @param nMaxCars  maximum number of characters allowed, or -1 for no limit.
 * @param papszOptions NULL-terminated array of options. Unused for now.
 * @param[out] pnBufLength size of output string (must be non-NULL)

 * @return pointer to an internal buffer containing a line of text read
 * from the file or NULL if the end of file was encountered or the maximum
 * number of characters allowed reached.
 *
 */
const char *CPLReadLine3L(VSILFILE *fp, int nMaxCars, int *pnBufLength,
                          CPL_UNUSED CSLConstList papszOptions)
{
    /* -------------------------------------------------------------------- */
    /*      Cleanup case.                                                   */
    /* -------------------------------------------------------------------- */
    if (fp == nullptr)
    {
        CPLReadLineBuffer(-1);
        return nullptr;
    }

    /* -------------------------------------------------------------------- */
    /*      Loop reading chunks of the line till we get to the end of       */
    /*      the line.                                                       */
    /* -------------------------------------------------------------------- */
    char *pszRLBuffer = nullptr;
    const size_t nChunkSize = 40;
    char szChunk[nChunkSize] = {};
    size_t nChunkBytesRead = 0;
    size_t nChunkBytesConsumed = 0;

    *pnBufLength = 0;
    szChunk[0] = 0;

    while (true)
    {
        /* --------------------------------------------------------------------
         */
        /*      Read a chunk from the input file. */
        /* --------------------------------------------------------------------
         */
        if (*pnBufLength > INT_MAX - static_cast<int>(nChunkSize) - 1)
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "Too big line : more than 2 billion characters!.");
            CPLReadLineBuffer(-1);
            return nullptr;
        }

        pszRLBuffer =
            CPLReadLineBuffer(static_cast<int>(*pnBufLength + nChunkSize + 1));
        if (pszRLBuffer == nullptr)
            return nullptr;

        if (nChunkBytesRead == nChunkBytesConsumed + 1)
        {

            // case where one character is left over from last read.
            szChunk[0] = szChunk[nChunkBytesConsumed];

            nChunkBytesConsumed = 0;
            nChunkBytesRead = VSIFReadL(szChunk + 1, 1, nChunkSize - 1, fp) + 1;
        }
        else
        {
            nChunkBytesConsumed = 0;

            // fresh read.
            nChunkBytesRead = VSIFReadL(szChunk, 1, nChunkSize, fp);
            if (nChunkBytesRead == 0)
            {
                if (*pnBufLength == 0)
                    return nullptr;

                break;
            }
        }

        /* --------------------------------------------------------------------
         */
        /*      copy over characters watching for end-of-line. */
        /* --------------------------------------------------------------------
         */
        bool bBreak = false;
        while (nChunkBytesConsumed < nChunkBytesRead - 1 && !bBreak)
        {
            if ((szChunk[nChunkBytesConsumed] == knCR &&
                 szChunk[nChunkBytesConsumed + 1] == knLF) ||
                (szChunk[nChunkBytesConsumed] == knLF &&
                 szChunk[nChunkBytesConsumed + 1] == knCR))
            {
                nChunkBytesConsumed += 2;
                bBreak = true;
            }
            else if (szChunk[nChunkBytesConsumed] == knLF ||
                     szChunk[nChunkBytesConsumed] == knCR)
            {
                nChunkBytesConsumed += 1;
                bBreak = true;
            }
            else
            {
                pszRLBuffer[(*pnBufLength)++] = szChunk[nChunkBytesConsumed++];
                if (nMaxCars >= 0 && *pnBufLength == nMaxCars)
                {
                    CPLError(CE_Failure, CPLE_AppDefined,
                             "Maximum number of characters allowed reached.");
                    return nullptr;
                }
            }
        }

        if (bBreak)
            break;

        /* --------------------------------------------------------------------
         */
        /*      If there is a remaining character and it is not a newline */
        /*      consume it.  If it is a newline, but we are clearly at the */
        /*      end of the file then consume it. */
        /* --------------------------------------------------------------------
         */
        if (nChunkBytesConsumed == nChunkBytesRead - 1 &&
            nChunkBytesRead < nChunkSize)
        {
            if (szChunk[nChunkBytesConsumed] == knLF ||
                szChunk[nChunkBytesConsumed] == knCR)
            {
                nChunkBytesConsumed++;
                break;
            }

            pszRLBuffer[(*pnBufLength)++] = szChunk[nChunkBytesConsumed++];
            break;
        }
    }

    /* -------------------------------------------------------------------- */
    /*      If we have left over bytes after breaking out, seek back to     */
    /*      ensure they remain to be read next time.                        */
    /* -------------------------------------------------------------------- */
    if (nChunkBytesConsumed < nChunkBytesRead)
    {
        const size_t nBytesToPush = nChunkBytesRead - nChunkBytesConsumed;

        if (VSIFSeekL(fp, VSIFTellL(fp) - nBytesToPush, SEEK_SET) != 0)
            return nullptr;
    }

    pszRLBuffer[*pnBufLength] = '\0';

    return pszRLBuffer;
}

/************************************************************************/
/*                            CPLScanString()                           */
/************************************************************************/

/**
 * Scan up to a maximum number of characters from a given string,
 * allocate a buffer for a new string and fill it with scanned characters.
 *
 * @param pszString String containing characters to be scanned. It may be
 * terminated with a null character.
 *
 * @param nMaxLength The maximum number of character to read. Less
 * characters will be read if a null character is encountered.
 *
 * @param bTrimSpaces If TRUE, trim ending spaces from the input string.
 * Character considered as empty using isspace(3) function.
 *
 * @param bNormalize If TRUE, replace ':' symbol with the '_'. It is needed if
 * resulting string will be used in CPL dictionaries.
 *
 * @return Pointer to the resulting string buffer. Caller responsible to free
 * this buffer with CPLFree().
 */

char *CPLScanString(const char *pszString, int nMaxLength, int bTrimSpaces,
                    int bNormalize)
{
    if (!pszString)
        return nullptr;

    if (!nMaxLength)
        return CPLStrdup("");

    char *pszBuffer = static_cast<char *>(CPLMalloc(nMaxLength + 1));
    if (!pszBuffer)
        return nullptr;

    strncpy(pszBuffer, pszString, nMaxLength);
    pszBuffer[nMaxLength] = '\0';

    if (bTrimSpaces)
    {
        size_t i = strlen(pszBuffer);
        while (i > 0)
        {
            i--;
            if (!isspace(static_cast<unsigned char>(pszBuffer[i])))
                break;
            pszBuffer[i] = '\0';
        }
    }

    if (bNormalize)
    {
        size_t i = strlen(pszBuffer);
        while (i > 0)
        {
            i--;
            if (pszBuffer[i] == ':')
                pszBuffer[i] = '_';
        }
    }

    return pszBuffer;
}

/************************************************************************/
/*                             CPLScanLong()                            */
/************************************************************************/

/**
 * Scan up to a maximum number of characters from a string and convert
 * the result to a long.
 *
 * @param pszString String containing characters to be scanned. It may be
 * terminated with a null character.
 *
 * @param nMaxLength The maximum number of character to consider as part
 * of the number. Less characters will be considered if a null character
 * is encountered.
 *
 * @return Long value, converted from its ASCII form.
 */

long CPLScanLong(const char *pszString, int nMaxLength)
{
    CPLAssert(nMaxLength >= 0);
    if (pszString == nullptr)
        return 0;
    const size_t nLength = CPLStrnlen(pszString, nMaxLength);
    const std::string osValue(pszString, nLength);
    return atol(osValue.c_str());
}

/************************************************************************/
/*                            CPLScanULong()                            */
/************************************************************************/

/**
 * Scan up to a maximum number of characters from a string and convert
 * the result to a unsigned long.
 *
 * @param pszString String containing characters to be scanned. It may be
 * terminated with a null character.
 *
 * @param nMaxLength The maximum number of character to consider as part
 * of the number. Less characters will be considered if a null character
 * is encountered.
 *
 * @return Unsigned long value, converted from its ASCII form.
 */

unsigned long CPLScanULong(const char *pszString, int nMaxLength)
{
    CPLAssert(nMaxLength >= 0);
    if (pszString == nullptr)
        return 0;
    const size_t nLength = CPLStrnlen(pszString, nMaxLength);
    const std::string osValue(pszString, nLength);
    return strtoul(osValue.c_str(), nullptr, 10);
}

/************************************************************************/
/*                           CPLScanUIntBig()                           */
/************************************************************************/

/**
 * Extract big integer from string.
 *
 * Scan up to a maximum number of characters from a string and convert
 * the result to a GUIntBig.
 *
 * @param pszString String containing characters to be scanned. It may be
 * terminated with a null character.
 *
 * @param nMaxLength The maximum number of character to consider as part
 * of the number. Less characters will be considered if a null character
 * is encountered.
 *
 * @return GUIntBig value, converted from its ASCII form.
 */

GUIntBig CPLScanUIntBig(const char *pszString, int nMaxLength)
{
    CPLAssert(nMaxLength >= 0);
    if (pszString == nullptr)
        return 0;
    const size_t nLength = CPLStrnlen(pszString, nMaxLength);
    const std::string osValue(pszString, nLength);

    /* -------------------------------------------------------------------- */
    /*      Fetch out the result                                            */
    /* -------------------------------------------------------------------- */
    return strtoull(osValue.c_str(), nullptr, 10);
}

/************************************************************************/
/*                           CPLAtoGIntBig()                            */
/************************************************************************/

/**
 * Convert a string to a 64 bit signed integer.
 *
 * @param pszString String containing 64 bit signed integer.
 * @return 64 bit signed integer.
 */

GIntBig CPLAtoGIntBig(const char *pszString)
{
    return atoll(pszString);
}

#if defined(__MINGW32__) || defined(__sun__)

// mingw atoll() doesn't return ERANGE in case of overflow
static int CPLAtoGIntBigExHasOverflow(const char *pszString, GIntBig nVal)
{
    if (strlen(pszString) <= 18)
        return FALSE;
    while (*pszString == ' ')
        pszString++;
    if (*pszString == '+')
        pszString++;
    char szBuffer[32] = {};
/* x86_64-w64-mingw32-g++ (GCC) 4.8.2 annoyingly warns */
#ifdef HAVE_GCC_DIAGNOSTIC_PUSH
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wformat"
#endif
    snprintf(szBuffer, sizeof(szBuffer), CPL_FRMT_GIB, nVal);
#ifdef HAVE_GCC_DIAGNOSTIC_PUSH
#pragma GCC diagnostic pop
#endif
    return strcmp(szBuffer, pszString) != 0;
}

#endif

/************************************************************************/
/*                          CPLAtoGIntBigEx()                           */
/************************************************************************/

/**
 * Convert a string to a 64 bit signed integer.
 *
 * @param pszString String containing 64 bit signed integer.
 * @param bWarn Issue a warning if an overflow occurs during conversion
 * @param pbOverflow Pointer to an integer to store if an overflow occurred, or
 *        NULL
 * @return 64 bit signed integer.
 */

GIntBig CPLAtoGIntBigEx(const char *pszString, int bWarn, int *pbOverflow)
{
    errno = 0;
    GIntBig nVal = strtoll(pszString, nullptr, 10);
    if (errno == ERANGE
#if defined(__MINGW32__) || defined(__sun__)
        || CPLAtoGIntBigExHasOverflow(pszString, nVal)
#endif
    )
    {
        if (pbOverflow)
            *pbOverflow = TRUE;
        if (bWarn)
        {
            CPLError(CE_Warning, CPLE_AppDefined,
                     "64 bit integer overflow when converting %s", pszString);
        }
        while (*pszString == ' ')
            pszString++;
        return (*pszString == '-') ? GINTBIG_MIN : GINTBIG_MAX;
    }
    else if (pbOverflow)
    {
        *pbOverflow = FALSE;
    }
    return nVal;
}

/************************************************************************/
/*                           CPLScanPointer()                           */
/************************************************************************/

/**
 * Extract pointer from string.
 *
 * Scan up to a maximum number of characters from a string and convert
 * the result to a pointer.
 *
 * @param pszString String containing characters to be scanned. It may be
 * terminated with a null character.
 *
 * @param nMaxLength The maximum number of character to consider as part
 * of the number. Less characters will be considered if a null character
 * is encountered.
 *
 * @return pointer value, converted from its ASCII form.
 */

void *CPLScanPointer(const char *pszString, int nMaxLength)
{
    char szTemp[128] = {};

    /* -------------------------------------------------------------------- */
    /*      Compute string into local buffer, and terminate it.             */
    /* -------------------------------------------------------------------- */
    if (nMaxLength > static_cast<int>(sizeof(szTemp)) - 1)
        nMaxLength = sizeof(szTemp) - 1;

    strncpy(szTemp, pszString, nMaxLength);
    szTemp[nMaxLength] = '\0';

    /* -------------------------------------------------------------------- */
    /*      On MSVC we have to scanf pointer values without the 0x          */
    /*      prefix.                                                         */
    /* -------------------------------------------------------------------- */
    if (STARTS_WITH_CI(szTemp, "0x"))
    {
        void *pResult = nullptr;

#if defined(__MSVCRT__) || (defined(_WIN32) && defined(_MSC_VER))
        // cppcheck-suppress invalidscanf
        sscanf(szTemp + 2, "%p", &pResult);
#else
        // cppcheck-suppress invalidscanf
        sscanf(szTemp, "%p", &pResult);

        // Solaris actually behaves like MSVCRT.
        if (pResult == nullptr)
        {
            // cppcheck-suppress invalidscanf
            sscanf(szTemp + 2, "%p", &pResult);
        }
#endif
        return pResult;
    }

#if SIZEOF_VOIDP == 8
    return reinterpret_cast<void *>(CPLScanUIntBig(szTemp, nMaxLength));
#else
    return reinterpret_cast<void *>(CPLScanULong(szTemp, nMaxLength));
#endif
}

/************************************************************************/
/*                             CPLScanDouble()                          */
/************************************************************************/

/**
 * Extract double from string.
 *
 * Scan up to a maximum number of characters from a string and convert the
 * result to a double. This function uses CPLAtof() to convert string to
 * double value, so it uses a comma as a decimal delimiter.
 *
 * @param pszString String containing characters to be scanned. It may be
 * terminated with a null character.
 *
 * @param nMaxLength The maximum number of character to consider as part
 * of the number. Less characters will be considered if a null character
 * is encountered.
 *
 * @return Double value, converted from its ASCII form.
 */

double CPLScanDouble(const char *pszString, int nMaxLength)
{
    char szValue[32] = {};
    char *pszValue = nullptr;

    if (nMaxLength + 1 < static_cast<int>(sizeof(szValue)))
        pszValue = szValue;
    else
        pszValue = static_cast<char *>(CPLMalloc(nMaxLength + 1));

    /* -------------------------------------------------------------------- */
    /*      Compute string into local buffer, and terminate it.             */
    /* -------------------------------------------------------------------- */
    strncpy(pszValue, pszString, nMaxLength);
    pszValue[nMaxLength] = '\0';

    /* -------------------------------------------------------------------- */
    /*      Make a pass through converting 'D's to 'E's.                    */
    /* -------------------------------------------------------------------- */
    for (int i = 0; i < nMaxLength; i++)
        if (pszValue[i] == 'd' || pszValue[i] == 'D')
            pszValue[i] = 'E';

    /* -------------------------------------------------------------------- */
    /*      The conversion itself.                                          */
    /* -------------------------------------------------------------------- */
    const double dfValue = CPLAtof(pszValue);

    if (pszValue != szValue)
        CPLFree(pszValue);
    return dfValue;
}

/************************************************************************/
/*                      CPLPrintString()                                */
/************************************************************************/

/**
 * Copy the string pointed to by pszSrc, NOT including the terminating
 * `\\0' character, to the array pointed to by pszDest.
 *
 * @param pszDest Pointer to the destination string buffer. Should be
 * large enough to hold the resulting string.
 *
 * @param pszSrc Pointer to the source buffer.
 *
 * @param nMaxLen Maximum length of the resulting string. If string length
 * is greater than nMaxLen, it will be truncated.
 *
 * @return Number of characters printed.
 */

int CPLPrintString(char *pszDest, const char *pszSrc, int nMaxLen)
{
    if (!pszDest)
        return 0;

    if (!pszSrc)
    {
        *pszDest = '\0';
        return 1;
    }

    int nChars = 0;
    char *pszTemp = pszDest;

    while (nChars < nMaxLen && *pszSrc)
    {
        *pszTemp++ = *pszSrc++;
        nChars++;
    }

    return nChars;
}

/************************************************************************/
/*                         CPLPrintStringFill()                         */
/************************************************************************/

/**
 * Copy the string pointed to by pszSrc, NOT including the terminating
 * `\\0' character, to the array pointed to by pszDest. Remainder of the
 * destination string will be filled with space characters. This is only
 * difference from the PrintString().
 *
 * @param pszDest Pointer to the destination string buffer. Should be
 * large enough to hold the resulting string.
 *
 * @param pszSrc Pointer to the source buffer.
 *
 * @param nMaxLen Maximum length of the resulting string. If string length
 * is greater than nMaxLen, it will be truncated.
 *
 * @return Number of characters printed.
 */

int CPLPrintStringFill(char *pszDest, const char *pszSrc, int nMaxLen)
{
    if (!pszDest)
        return 0;

    if (!pszSrc)
    {
        memset(pszDest, ' ', nMaxLen);
        return nMaxLen;
    }

    char *pszTemp = pszDest;
    while (nMaxLen && *pszSrc)
    {
        *pszTemp++ = *pszSrc++;
        nMaxLen--;
    }

    if (nMaxLen)
        memset(pszTemp, ' ', nMaxLen);

    return nMaxLen;
}

/************************************************************************/
/*                          CPLPrintInt32()                             */
/************************************************************************/

/**
 * Print GInt32 value into specified string buffer. This string will not
 * be NULL-terminated.
 *
 * @param pszBuffer Pointer to the destination string buffer. Should be
 * large enough to hold the resulting string. Note, that the string will
 * not be NULL-terminated, so user should do this himself, if needed.
 *
 * @param iValue Numerical value to print.
 *
 * @param nMaxLen Maximum length of the resulting string. If string length
 * is greater than nMaxLen, it will be truncated.
 *
 * @return Number of characters printed.
 */

int CPLPrintInt32(char *pszBuffer, GInt32 iValue, int nMaxLen)
{
    if (!pszBuffer)
        return 0;

    if (nMaxLen >= 64)
        nMaxLen = 63;

    char szTemp[64] = {};

#if UINT_MAX == 65535
    snprintf(szTemp, sizeof(szTemp), "%*ld", nMaxLen, iValue);
#else
    snprintf(szTemp, sizeof(szTemp), "%*d", nMaxLen, iValue);
#endif

    return CPLPrintString(pszBuffer, szTemp, nMaxLen);
}

/************************************************************************/
/*                          CPLPrintUIntBig()                           */
/************************************************************************/

/**
 * Print GUIntBig value into specified string buffer. This string will not
 * be NULL-terminated.
 *
 * @param pszBuffer Pointer to the destination string buffer. Should be
 * large enough to hold the resulting string. Note, that the string will
 * not be NULL-terminated, so user should do this himself, if needed.
 *
 * @param iValue Numerical value to print.
 *
 * @param nMaxLen Maximum length of the resulting string. If string length
 * is greater than nMaxLen, it will be truncated.
 *
 * @return Number of characters printed.
 */

int CPLPrintUIntBig(char *pszBuffer, GUIntBig iValue, int nMaxLen)
{
    if (!pszBuffer)
        return 0;

    if (nMaxLen >= 64)
        nMaxLen = 63;

    char szTemp[64] = {};

#if defined(__MSVCRT__) || (defined(_WIN32) && defined(_MSC_VER))
/* x86_64-w64-mingw32-g++ (GCC) 4.8.2 annoyingly warns */
#ifdef HAVE_GCC_DIAGNOSTIC_PUSH
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wformat"
#pragma GCC diagnostic ignored "-Wformat-extra-args"
#endif
    snprintf(szTemp, sizeof(szTemp), "%*I64u", nMaxLen, iValue);
#ifdef HAVE_GCC_DIAGNOSTIC_PUSH
#pragma GCC diagnostic pop
#endif
#else
    snprintf(szTemp, sizeof(szTemp), "%*llu", nMaxLen, iValue);
#endif

    return CPLPrintString(pszBuffer, szTemp, nMaxLen);
}

/************************************************************************/
/*                          CPLPrintPointer()                           */
/************************************************************************/

/**
 * Print pointer value into specified string buffer. This string will not
 * be NULL-terminated.
 *
 * @param pszBuffer Pointer to the destination string buffer. Should be
 * large enough to hold the resulting string. Note, that the string will
 * not be NULL-terminated, so user should do this himself, if needed.
 *
 * @param pValue Pointer to ASCII encode.
 *
 * @param nMaxLen Maximum length of the resulting string. If string length
 * is greater than nMaxLen, it will be truncated.
 *
 * @return Number of characters printed.
 */

int CPLPrintPointer(char *pszBuffer, void *pValue, int nMaxLen)
{
    if (!pszBuffer)
        return 0;

    if (nMaxLen >= 64)
        nMaxLen = 63;

    char szTemp[64] = {};

    snprintf(szTemp, sizeof(szTemp), "%p", pValue);

    // On windows, and possibly some other platforms the sprintf("%p")
    // does not prefix things with 0x so it is hard to know later if the
    // value is hex encoded.  Fix this up here.

    if (!STARTS_WITH_CI(szTemp, "0x"))
        snprintf(szTemp, sizeof(szTemp), "0x%p", pValue);

    return CPLPrintString(pszBuffer, szTemp, nMaxLen);
}

/************************************************************************/
/*                          CPLPrintDouble()                            */
/************************************************************************/

/**
 * Print double value into specified string buffer. Exponential character
 * flag 'E' (or 'e') will be replaced with 'D', as in Fortran. Resulting
 * string will not to be NULL-terminated.
 *
 * @param pszBuffer Pointer to the destination string buffer. Should be
 * large enough to hold the resulting string. Note, that the string will
 * not be NULL-terminated, so user should do this himself, if needed.
 *
 * @param pszFormat Format specifier (for example, "%16.9E").
 *
 * @param dfValue Numerical value to print.
 *
 * @param pszLocale Unused.
 *
 * @return Number of characters printed.
 */

int CPLPrintDouble(char *pszBuffer, const char *pszFormat, double dfValue,
                   CPL_UNUSED const char *pszLocale)
{
    if (!pszBuffer)
        return 0;

    const int knDoubleBufferSize = 64;
    char szTemp[knDoubleBufferSize] = {};

    CPLsnprintf(szTemp, knDoubleBufferSize, pszFormat, dfValue);
    szTemp[knDoubleBufferSize - 1] = '\0';

    for (int i = 0; szTemp[i] != '\0'; i++)
    {
        if (szTemp[i] == 'E' || szTemp[i] == 'e')
            szTemp[i] = 'D';
    }

    return CPLPrintString(pszBuffer, szTemp, 64);
}

/************************************************************************/
/*                            CPLPrintTime()                            */
/************************************************************************/

/**
 * Print specified time value accordingly to the format options and
 * specified locale name. This function does following:
 *
 *  - if locale parameter is not NULL, the current locale setting will be
 *  stored and replaced with the specified one;
 *  - format time value with the strftime(3) function;
 *  - restore back current locale, if was saved.
 *
 * @param pszBuffer Pointer to the destination string buffer. Should be
 * large enough to hold the resulting string. Note, that the string will
 * not be NULL-terminated, so user should do this himself, if needed.
 *
 * @param nMaxLen Maximum length of the resulting string. If string length is
 * greater than nMaxLen, it will be truncated.
 *
 * @param pszFormat Controls the output format. Options are the same as
 * for strftime(3) function.
 *
 * @param poBrokenTime Pointer to the broken-down time structure. May be
 * requested with the VSIGMTime() and VSILocalTime() functions.
 *
 * @param pszLocale Pointer to a character string containing locale name
 * ("C", "POSIX", "us_US", "ru_RU.KOI8-R" etc.). If NULL we will not
 * manipulate with locale settings and current process locale will be used for
 * printing. Be aware that it may be unsuitable to use current locale for
 * printing time, because all names will be printed in your native language,
 * as well as time format settings also may be adjusted differently from the
 * C/POSIX defaults. To solve these problems this option was introduced.
 *
 * @return Number of characters printed.
 */

int CPLPrintTime(char *pszBuffer, int nMaxLen, const char *pszFormat,
                 const struct tm *poBrokenTime, const char *pszLocale)
{
    char *pszTemp =
        static_cast<char *>(CPLMalloc((nMaxLen + 1) * sizeof(char)));

    if (pszLocale && EQUAL(pszLocale, "C") &&
        strcmp(pszFormat, "%a, %d %b %Y %H:%M:%S GMT") == 0)
    {
        // Particular case when formatting RFC822 datetime, to avoid locale
        // change
        static const char *const aszMonthStr[] = {"Jan", "Feb", "Mar", "Apr",
                                                  "May", "Jun", "Jul", "Aug",
                                                  "Sep", "Oct", "Nov", "Dec"};
        static const char *const aszDayOfWeek[] = {"Sun", "Mon", "Tue", "Wed",
                                                   "Thu", "Fri", "Sat"};
        snprintf(pszTemp, nMaxLen + 1, "%s, %02d %s %04d %02d:%02d:%02d GMT",
                 aszDayOfWeek[std::max(0, std::min(6, poBrokenTime->tm_wday))],
                 poBrokenTime->tm_mday,
                 aszMonthStr[std::max(0, std::min(11, poBrokenTime->tm_mon))],
                 poBrokenTime->tm_year + 1900, poBrokenTime->tm_hour,
                 poBrokenTime->tm_min, poBrokenTime->tm_sec);
    }
    else
    {
#if defined(HAVE_LOCALE_H) && defined(HAVE_SETLOCALE)
        char *pszCurLocale = NULL;

        if (pszLocale || EQUAL(pszLocale, ""))
        {
            // Save the current locale.
            pszCurLocale = CPLsetlocale(LC_ALL, NULL);
            // Set locale to the specified value.
            CPLsetlocale(LC_ALL, pszLocale);
        }
#else
        (void)pszLocale;
#endif

        if (!strftime(pszTemp, nMaxLen + 1, pszFormat, poBrokenTime))
            memset(pszTemp, 0, nMaxLen + 1);

#if defined(HAVE_LOCALE_H) && defined(HAVE_SETLOCALE)
        // Restore stored locale back.
        if (pszCurLocale)
            CPLsetlocale(LC_ALL, pszCurLocale);
#endif
    }

    const int nChars = CPLPrintString(pszBuffer, pszTemp, nMaxLen);

    CPLFree(pszTemp);

    return nChars;
}

/************************************************************************/
/*                       CPLVerifyConfiguration()                       */
/************************************************************************/

void CPLVerifyConfiguration()

{
    /* -------------------------------------------------------------------- */
    /*      Verify data types.                                              */
    /* -------------------------------------------------------------------- */
    static_assert(sizeof(short) == 2);   // We unfortunately rely on this
    static_assert(sizeof(int) == 4);     // We unfortunately rely on this
    static_assert(sizeof(float) == 4);   // We unfortunately rely on this
    static_assert(sizeof(double) == 8);  // We unfortunately rely on this
    static_assert(sizeof(GInt64) == 8);
    static_assert(sizeof(GInt32) == 4);
    static_assert(sizeof(GInt16) == 2);
    static_assert(sizeof(GByte) == 1);

    /* -------------------------------------------------------------------- */
    /*      Verify byte order                                               */
    /* -------------------------------------------------------------------- */
#ifdef CPL_LSB
#if __cplusplus >= 202002L
    static_assert(std::endian::native == std::endian::little);
#elif defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__)
    static_assert(__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__);
#endif
#elif defined(CPL_MSB)
#if __cplusplus >= 202002L
    static_assert(std::endian::native == std::endian::big);
#elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__)
    static_assert(__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__);
#endif
#else
#error "CPL_LSB or CPL_MSB must be defined"
#endif
}

#ifdef DEBUG_CONFIG_OPTIONS

static CPLMutex *hRegisterConfigurationOptionMutex = nullptr;
static std::set<CPLString> *paoGetKeys = nullptr;
static std::set<CPLString> *paoSetKeys = nullptr;

/************************************************************************/
/*                      CPLShowAccessedOptions()                        */
/************************************************************************/

static void CPLShowAccessedOptions()
{
    std::set<CPLString>::iterator aoIter;

    printf("Configuration options accessed in reading : "); /*ok*/
    aoIter = paoGetKeys->begin();
    while (aoIter != paoGetKeys->end())
    {
        printf("%s, ", (*aoIter).c_str()); /*ok*/
        ++aoIter;
    }
    printf("\n"); /*ok*/

    printf("Configuration options accessed in writing : "); /*ok*/
    aoIter = paoSetKeys->begin();
    while (aoIter != paoSetKeys->end())
    {
        printf("%s, ", (*aoIter).c_str()); /*ok*/
        ++aoIter;
    }
    printf("\n"); /*ok*/

    delete paoGetKeys;
    delete paoSetKeys;
    paoGetKeys = nullptr;
    paoSetKeys = nullptr;
}

/************************************************************************/
/*                       CPLAccessConfigOption()                        */
/************************************************************************/

static void CPLAccessConfigOption(const char *pszKey, bool bGet)
{
    CPLMutexHolderD(&hRegisterConfigurationOptionMutex);
    if (paoGetKeys == nullptr)
    {
        paoGetKeys = new std::set<CPLString>;
        paoSetKeys = new std::set<CPLString>;
        atexit(CPLShowAccessedOptions);
    }
    if (bGet)
        paoGetKeys->insert(pszKey);
    else
        paoSetKeys->insert(pszKey);
}
#endif

/************************************************************************/
/*                         CPLGetConfigOption()                         */
/************************************************************************/

/**
 * Get the value of a configuration option.
 *
 * The value is the value of a (key, value) option set with
 * CPLSetConfigOption(), or CPLSetThreadLocalConfigOption() of the same
 * thread. If the given option was no defined with
 * CPLSetConfigOption(), it tries to find it in environment variables.
 *
 * Note: the string returned by CPLGetConfigOption() might be short-lived, and
 * in particular it will become invalid after a call to CPLSetConfigOption()
 * with the same key.
 *
 * To override temporary a potentially existing option with a new value, you
 * can use the following snippet :
 * \code{.cpp}
 *     // backup old value
 *     const char* pszOldValTmp = CPLGetConfigOption(pszKey, NULL);
 *     char* pszOldVal = pszOldValTmp ? CPLStrdup(pszOldValTmp) : NULL;
 *     // override with new value
 *     CPLSetConfigOption(pszKey, pszNewVal);
 *     // do something useful
 *     // restore old value
 *     CPLSetConfigOption(pszKey, pszOldVal);
 *     CPLFree(pszOldVal);
 * \endcode
 *
 * @param pszKey the key of the option to retrieve
 * @param pszDefault a default value if the key does not match existing defined
 *     options (may be NULL)
 * @return the value associated to the key, or the default value if not found
 *
 * @see CPLSetConfigOption(), https://gdal.org/user/configoptions.html
 */
const char *CPL_STDCALL CPLGetConfigOption(const char *pszKey,
                                           const char *pszDefault)

{
    const char *pszResult = CPLGetThreadLocalConfigOption(pszKey, nullptr);

    if (pszResult == nullptr)
    {
        pszResult = CPLGetGlobalConfigOption(pszKey, nullptr);
    }

    if (gbIgnoreEnvVariables)
    {
        const char *pszEnvVar = getenv(pszKey);
        if (pszEnvVar != nullptr)
        {
            CPLDebug("CPL",
                     "Ignoring environment variable %s=%s because of "
                     "ignore-env-vars=yes setting in configuration file",
                     pszKey, pszEnvVar);
        }
    }
    else if (pszResult == nullptr)
    {
        pszResult = getenv(pszKey);
    }

    if (pszResult == nullptr)
        return pszDefault;

    return pszResult;
}

/************************************************************************/
/*                         CPLGetConfigOptions()                        */
/************************************************************************/

/**
 * Return the list of configuration options as KEY=VALUE pairs.
 *
 * The list is the one set through the CPLSetConfigOption() API.
 *
 * Options that through environment variables or with
 * CPLSetThreadLocalConfigOption() will *not* be listed.
 *
 * @return a copy of the list, to be freed with CSLDestroy().
 */
char **CPLGetConfigOptions(void)
{
    CPLMutexHolderD(&hConfigMutex);
    return CSLDuplicate(const_cast<char **>(g_papszConfigOptions));
}

/************************************************************************/
/*                         CPLSetConfigOptions()                        */
/************************************************************************/

/**
 * Replace the full list of configuration options with the passed list of
 * KEY=VALUE pairs.
 *
 * This has the same effect of clearing the existing list, and setting
 * individually each pair with the CPLSetConfigOption() API.
 *
 * This does not affect options set through environment variables or with
 * CPLSetThreadLocalConfigOption().
 *
 * The passed list is copied by the function.
 *
 * @param papszConfigOptions the new list (or NULL).
 *
 */
void CPLSetConfigOptions(const char *const *papszConfigOptions)
{
    CPLMutexHolderD(&hConfigMutex);
    CSLDestroy(const_cast<char **>(g_papszConfigOptions));
    g_papszConfigOptions = const_cast<volatile char **>(
        CSLDuplicate(const_cast<char **>(papszConfigOptions)));
}

/************************************************************************/
/*                   CPLGetThreadLocalConfigOption()                    */
/************************************************************************/

/** Same as CPLGetConfigOption() but only with options set with
 * CPLSetThreadLocalConfigOption() */
const char *CPL_STDCALL CPLGetThreadLocalConfigOption(const char *pszKey,
                                                      const char *pszDefault)

{
#ifdef DEBUG_CONFIG_OPTIONS
    CPLAccessConfigOption(pszKey, TRUE);
#endif

    const char *pszResult = nullptr;

    int bMemoryError = FALSE;
    char **papszTLConfigOptions = reinterpret_cast<char **>(
        CPLGetTLSEx(CTLS_CONFIGOPTIONS, &bMemoryError));
    if (papszTLConfigOptions != nullptr)
        pszResult = CSLFetchNameValue(papszTLConfigOptions, pszKey);

    if (pszResult == nullptr)
        return pszDefault;

    return pszResult;
}

/************************************************************************/
/*                   CPLGetGlobalConfigOption()                         */
/************************************************************************/

/** Same as CPLGetConfigOption() but excludes environment variables and
 *  options set with CPLSetThreadLocalConfigOption().
 *  This function should generally not be used by applications, which should
 *  use CPLGetConfigOption() instead.
 *  @since 3.8 */
const char *CPL_STDCALL CPLGetGlobalConfigOption(const char *pszKey,
                                                 const char *pszDefault)
{
#ifdef DEBUG_CONFIG_OPTIONS
    CPLAccessConfigOption(pszKey, TRUE);
#endif

    CPLMutexHolderD(&hConfigMutex);

    const char *pszResult =
        CSLFetchNameValue(const_cast<char **>(g_papszConfigOptions), pszKey);

    if (pszResult == nullptr)
        return pszDefault;

    return pszResult;
}

/************************************************************************/
/*                    CPLSubscribeToSetConfigOption()                   */
/************************************************************************/

/**
 * Install a callback that will be notified of calls to CPLSetConfigOption()/
 * CPLSetThreadLocalConfigOption()
 *
 * @param pfnCallback Callback. Must not be NULL
 * @param pUserData Callback user data. May be NULL.
 * @return subscriber ID that can be used with CPLUnsubscribeToSetConfigOption()
 * @since GDAL 3.7
 */

int CPLSubscribeToSetConfigOption(CPLSetConfigOptionSubscriber pfnCallback,
                                  void *pUserData)
{
    CPLMutexHolderD(&hConfigMutex);
    for (int nId = 0;
         nId < static_cast<int>(gSetConfigOptionSubscribers.size()); ++nId)
    {
        if (!gSetConfigOptionSubscribers[nId].first)
        {
            gSetConfigOptionSubscribers[nId].first = pfnCallback;
            gSetConfigOptionSubscribers[nId].second = pUserData;
            return nId;
        }
    }
    int nId = static_cast<int>(gSetConfigOptionSubscribers.size());
    gSetConfigOptionSubscribers.push_back(
        std::pair<CPLSetConfigOptionSubscriber, void *>(pfnCallback,
                                                        pUserData));
    return nId;
}

/************************************************************************/
/*                  CPLUnsubscribeToSetConfigOption()                   */
/************************************************************************/

/**
 * Remove a subscriber installed with CPLSubscribeToSetConfigOption()
 *
 * @param nId Subscriber id returned by CPLSubscribeToSetConfigOption()
 * @since GDAL 3.7
 */

void CPLUnsubscribeToSetConfigOption(int nId)
{
    CPLMutexHolderD(&hConfigMutex);
    if (nId == static_cast<int>(gSetConfigOptionSubscribers.size()) - 1)
    {
        gSetConfigOptionSubscribers.resize(gSetConfigOptionSubscribers.size() -
                                           1);
    }
    else if (nId >= 0 &&
             nId < static_cast<int>(gSetConfigOptionSubscribers.size()))
    {
        gSetConfigOptionSubscribers[nId].first = nullptr;
    }
}

/************************************************************************/
/*                  NotifyOtherComponentsConfigOptionChanged()          */
/************************************************************************/

static void NotifyOtherComponentsConfigOptionChanged(const char *pszKey,
                                                     const char *pszValue,
                                                     bool bThreadLocal)
{
    // When changing authentication parameters of virtual file systems,
    // partially invalidate cached state about file availability.
    if (STARTS_WITH_CI(pszKey, "AWS_") || STARTS_WITH_CI(pszKey, "GS_") ||
        STARTS_WITH_CI(pszKey, "GOOGLE_") ||
        STARTS_WITH_CI(pszKey, "GDAL_HTTP_HEADER_FILE") ||
        STARTS_WITH_CI(pszKey, "AZURE_") ||
        (STARTS_WITH_CI(pszKey, "SWIFT_") && !EQUAL(pszKey, "SWIFT_MAX_KEYS")))
    {
        VSICurlAuthParametersChanged();
    }

    if (!gSetConfigOptionSubscribers.empty())
    {
        for (const auto &iter : gSetConfigOptionSubscribers)
        {
            if (iter.first)
                iter.first(pszKey, pszValue, bThreadLocal, iter.second);
        }
    }
}

/************************************************************************/
/*                       CPLIsDebugEnabled()                            */
/************************************************************************/

static int gnDebug = -1;

/** Returns whether CPL_DEBUG is enabled.
 *
 * @since 3.11
 */
bool CPLIsDebugEnabled()
{
    if (gnDebug < 0)
    {
        // Check that apszKnownConfigOptions is correctly sorted with
        // STRCASECMP() criterion.
        for (size_t i = 1; i < CPL_ARRAYSIZE(apszKnownConfigOptions); ++i)
        {
            if (STRCASECMP(apszKnownConfigOptions[i - 1],
                           apszKnownConfigOptions[i]) >= 0)
            {
                CPLError(CE_Failure, CPLE_AppDefined,
                         "ERROR: apszKnownConfigOptions[] isn't correctly "
                         "sorted: %s >= %s",
                         apszKnownConfigOptions[i - 1],
                         apszKnownConfigOptions[i]);
            }
        }
        gnDebug = CPLTestBool(CPLGetConfigOption("CPL_DEBUG", "OFF"));
    }

    return gnDebug != 0;
}

/************************************************************************/
/*                       CPLDeclareKnownConfigOption()                  */
/************************************************************************/

static std::mutex goMutexDeclaredKnownConfigOptions;
static std::set<CPLString> goSetKnownConfigOptions;

/** Declare that the specified configuration option is known.
 *
 * This is useful to avoid a warning to be emitted on unknown configuration
 * options when CPL_DEBUG is enabled.
 *
 * @param pszKey Name of the configuration option to declare.
 * @param pszDefinition Unused for now. Must be set to nullptr.
 * @since 3.11
 */
void CPLDeclareKnownConfigOption(const char *pszKey,
                                 [[maybe_unused]] const char *pszDefinition)
{
    std::lock_guard oLock(goMutexDeclaredKnownConfigOptions);
    goSetKnownConfigOptions.insert(CPLString(pszKey).toupper());
}

/************************************************************************/
/*                       CPLGetKnownConfigOptions()                     */
/************************************************************************/

/** Return the list of known configuration options.
 *
 * Must be freed with CSLDestroy().
 * @since 3.11
 */
char **CPLGetKnownConfigOptions()
{
    std::lock_guard oLock(goMutexDeclaredKnownConfigOptions);
    CPLStringList aosList;
    for (const char *pszKey : apszKnownConfigOptions)
        aosList.AddString(pszKey);
    for (const auto &osKey : goSetKnownConfigOptions)
        aosList.AddString(osKey);
    return aosList.StealList();
}

/************************************************************************/
/*           CPLSetConfigOptionDetectUnknownConfigOption()              */
/************************************************************************/

static void CPLSetConfigOptionDetectUnknownConfigOption(const char *pszKey,
                                                        const char *pszValue)
{
    if (EQUAL(pszKey, "CPL_DEBUG"))
    {
        gnDebug = pszValue ? CPLTestBool(pszValue) : false;
    }
    else if (CPLIsDebugEnabled())
    {
        if (!std::binary_search(std::begin(apszKnownConfigOptions),
                                std::end(apszKnownConfigOptions), pszKey,
                                [](const char *a, const char *b)
                                { return STRCASECMP(a, b) < 0; }))
        {
            bool bFound;
            {
                std::lock_guard oLock(goMutexDeclaredKnownConfigOptions);
                bFound = cpl::contains(goSetKnownConfigOptions,
                                       CPLString(pszKey).toupper());
            }
            if (!bFound)
            {
                const char *pszOldValue = CPLGetConfigOption(pszKey, nullptr);
                if (!((!pszValue && !pszOldValue) ||
                      (pszValue && pszOldValue &&
                       EQUAL(pszValue, pszOldValue))))
                {
                    CPLError(CE_Warning, CPLE_AppDefined,
                             "Unknown configuration option '%s'.", pszKey);
                }
            }
        }
    }
}

/************************************************************************/
/*                         CPLSetConfigOption()                         */
/************************************************************************/

/**
 * Set a configuration option for GDAL/OGR use.
 *
 * Those options are defined as a (key, value) couple. The value corresponding
 * to a key can be got later with the CPLGetConfigOption() method.
 *
 * This mechanism is similar to environment variables, but options set with
 * CPLSetConfigOption() overrides, for CPLGetConfigOption() point of view,
 * values defined in the environment.
 *
 * If CPLSetConfigOption() is called several times with the same key, the
 * value provided during the last call will be used.
 *
 * Options can also be passed on the command line of most GDAL utilities
 * with '\--config KEY VALUE' (or '\--config KEY=VALUE' since GDAL 3.10).
 * For example, ogrinfo \--config CPL_DEBUG ON ~/data/test/point.shp
 *
 * This function can also be used to clear a setting by passing NULL as the
 * value (note: passing NULL will not unset an existing environment variable;
 * it will just unset a value previously set by CPLSetConfigOption()).
 *
 * Starting with GDAL 3.11, if CPL_DEBUG is enabled prior to this call, and
 * CPLSetConfigOption() is called with a key that is neither a known
 * configuration option of GDAL itself, or one that has been declared with
 * CPLDeclareKnownConfigOption(), a warning will be emitted.
 *
 * @param pszKey the key of the option
 * @param pszValue the value of the option, or NULL to clear a setting.
 *
 * @see https://gdal.org/user/configoptions.html
 */
void CPL_STDCALL CPLSetConfigOption(const char *pszKey, const char *pszValue)

{
#ifdef DEBUG_CONFIG_OPTIONS
    CPLAccessConfigOption(pszKey, FALSE);
#endif
    CPLMutexHolderD(&hConfigMutex);

#ifdef OGRAPISPY_ENABLED
    OGRAPISPYCPLSetConfigOption(pszKey, pszValue);
#endif

    CPLSetConfigOptionDetectUnknownConfigOption(pszKey, pszValue);

    g_papszConfigOptions = const_cast<volatile char **>(CSLSetNameValue(
        const_cast<char **>(g_papszConfigOptions), pszKey, pszValue));

    NotifyOtherComponentsConfigOptionChanged(pszKey, pszValue,
                                             /*bTheadLocal=*/false);
}

/************************************************************************/
/*                   CPLSetThreadLocalTLSFreeFunc()                     */
/************************************************************************/

/* non-stdcall wrapper function for CSLDestroy() (#5590) */
static void CPLSetThreadLocalTLSFreeFunc(void *pData)
{
    CSLDestroy(reinterpret_cast<char **>(pData));
}

/************************************************************************/
/*                   CPLSetThreadLocalConfigOption()                    */
/************************************************************************/

/**
 * Set a configuration option for GDAL/OGR use.
 *
 * Those options are defined as a (key, value) couple. The value corresponding
 * to a key can be got later with the CPLGetConfigOption() method.
 *
 * This function sets the configuration option that only applies in the
 * current thread, as opposed to CPLSetConfigOption() which sets an option
 * that applies on all threads. CPLSetThreadLocalConfigOption() will override
 * the effect of CPLSetConfigOption) for the current thread.
 *
 * This function can also be used to clear a setting by passing NULL as the
 * value (note: passing NULL will not unset an existing environment variable or
 * a value set through CPLSetConfigOption();
 * it will just unset a value previously set by
 * CPLSetThreadLocalConfigOption()).
 *
 * @param pszKey the key of the option
 * @param pszValue the value of the option, or NULL to clear a setting.
 */

void CPL_STDCALL CPLSetThreadLocalConfigOption(const char *pszKey,
                                               const char *pszValue)

{
#ifdef DEBUG_CONFIG_OPTIONS
    CPLAccessConfigOption(pszKey, FALSE);
#endif

#ifdef OGRAPISPY_ENABLED
    OGRAPISPYCPLSetThreadLocalConfigOption(pszKey, pszValue);
#endif

    int bMemoryError = FALSE;
    char **papszTLConfigOptions = reinterpret_cast<char **>(
        CPLGetTLSEx(CTLS_CONFIGOPTIONS, &bMemoryError));
    if (bMemoryError)
        return;

    CPLSetConfigOptionDetectUnknownConfigOption(pszKey, pszValue);

    papszTLConfigOptions =
        CSLSetNameValue(papszTLConfigOptions, pszKey, pszValue);

    CPLSetTLSWithFreeFunc(CTLS_CONFIGOPTIONS, papszTLConfigOptions,
                          CPLSetThreadLocalTLSFreeFunc);

    NotifyOtherComponentsConfigOptionChanged(pszKey, pszValue,
                                             /*bTheadLocal=*/true);
}

/************************************************************************/
/*                   CPLGetThreadLocalConfigOptions()                   */
/************************************************************************/

/**
 * Return the list of thread local configuration options as KEY=VALUE pairs.
 *
 * Options that through environment variables or with
 * CPLSetConfigOption() will *not* be listed.
 *
 * @return a copy of the list, to be freed with CSLDestroy().
 */
char **CPLGetThreadLocalConfigOptions(void)
{
    int bMemoryError = FALSE;
    char **papszTLConfigOptions = reinterpret_cast<char **>(
        CPLGetTLSEx(CTLS_CONFIGOPTIONS, &bMemoryError));
    if (bMemoryError)
        return nullptr;
    return CSLDuplicate(papszTLConfigOptions);
}

/************************************************************************/
/*                   CPLSetThreadLocalConfigOptions()                   */
/************************************************************************/

/**
 * Replace the full list of thread local configuration options with the
 * passed list of KEY=VALUE pairs.
 *
 * This has the same effect of clearing the existing list, and setting
 * individually each pair with the CPLSetThreadLocalConfigOption() API.
 *
 * This does not affect options set through environment variables or with
 * CPLSetConfigOption().
 *
 * The passed list is copied by the function.
 *
 * @param papszConfigOptions the new list (or NULL).
 *
 */
void CPLSetThreadLocalConfigOptions(const char *const *papszConfigOptions)
{
    int bMemoryError = FALSE;
    char **papszTLConfigOptions = reinterpret_cast<char **>(
        CPLGetTLSEx(CTLS_CONFIGOPTIONS, &bMemoryError));
    if (bMemoryError)
        return;
    CSLDestroy(papszTLConfigOptions);
    papszTLConfigOptions =
        CSLDuplicate(const_cast<char **>(papszConfigOptions));
    CPLSetTLSWithFreeFunc(CTLS_CONFIGOPTIONS, papszTLConfigOptions,
                          CPLSetThreadLocalTLSFreeFunc);
}

/************************************************************************/
/*                           CPLFreeConfig()                            */
/************************************************************************/

void CPL_STDCALL CPLFreeConfig()

{
    {
        CPLMutexHolderD(&hConfigMutex);

        CSLDestroy(const_cast<char **>(g_papszConfigOptions));
        g_papszConfigOptions = nullptr;

        int bMemoryError = FALSE;
        char **papszTLConfigOptions = reinterpret_cast<char **>(
            CPLGetTLSEx(CTLS_CONFIGOPTIONS, &bMemoryError));
        if (papszTLConfigOptions != nullptr)
        {
            CSLDestroy(papszTLConfigOptions);
            CPLSetTLS(CTLS_CONFIGOPTIONS, nullptr, FALSE);
        }
    }
    CPLDestroyMutex(hConfigMutex);
    hConfigMutex = nullptr;
}

/************************************************************************/
/*                    CPLLoadConfigOptionsFromFile()                    */
/************************************************************************/

/** Load configuration from a given configuration file.

A configuration file is a text file in a .ini style format, that lists
configuration options and their values.
Lines starting with # are comment lines.

Example:
\verbatim
[configoptions]
# set BAR as the value of configuration option FOO
FOO=BAR
\endverbatim

Starting with GDAL 3.5, a configuration file can also contain credentials
(or more generally options related to a virtual file system) for a given path
prefix, that can also be set with VSISetPathSpecificOption(). Credentials should
be put under a [credentials] section, and for each path prefix, under a relative
subsection whose name starts with "[." (e.g. "[.some_arbitrary_name]"), and
whose first key is "path".

Example:
\verbatim
[credentials]

[.private_bucket]
path=/vsis3/my_private_bucket
AWS_SECRET_ACCESS_KEY=...
AWS_ACCESS_KEY_ID=...

[.sentinel_s2_l1c]
path=/vsis3/sentinel-s2-l1c
AWS_REQUEST_PAYER=requester
\endverbatim

Starting with GDAL 3.6, a leading [directives] section might be added with
a "ignore-env-vars=yes" setting to indicate that, starting with that point,
all environment variables should be ignored, and only configuration options
defined in the [configoptions] sections or through the CPLSetConfigOption() /
CPLSetThreadLocalConfigOption() functions should be taken into account.

This function is typically called by CPLLoadConfigOptionsFromPredefinedFiles()

@param pszFilename File where to load configuration from.
@param bOverrideEnvVars Whether configuration options from the configuration
                        file should override environment variables.
@since GDAL 3.3
 */
void CPLLoadConfigOptionsFromFile(const char *pszFilename, int bOverrideEnvVars)
{
    VSILFILE *fp = VSIFOpenL(pszFilename, "rb");
    if (fp == nullptr)
        return;
    CPLDebug("CPL", "Loading configuration from %s", pszFilename);
    const char *pszLine;
    enum class Section
    {
        NONE,
        GENERAL,
        CONFIG_OPTIONS,
        CREDENTIALS,
    };
    Section eCurrentSection = Section::NONE;
    bool bInSubsection = false;
    std::string osPath;
    int nSectionCounter = 0;

    const auto IsSpaceOnly = [](const char *pszStr)
    {
        for (; *pszStr; ++pszStr)
        {
            if (!isspace(static_cast<unsigned char>(*pszStr)))
                return false;
        }
        return true;
    };

    while ((pszLine = CPLReadLine2L(fp, -1, nullptr)) != nullptr)
    {
        if (IsSpaceOnly(pszLine))
        {
            // Blank line
        }
        else if (pszLine[0] == '#')
        {
            // Comment line
        }
        else if (strcmp(pszLine, "[configoptions]") == 0)
        {
            nSectionCounter++;
            eCurrentSection = Section::CONFIG_OPTIONS;
        }
        else if (strcmp(pszLine, "[credentials]") == 0)
        {
            nSectionCounter++;
            eCurrentSection = Section::CREDENTIALS;
            bInSubsection = false;
            osPath.clear();
        }
        else if (strcmp(pszLine, "[directives]") == 0)
        {
            nSectionCounter++;
            if (nSectionCounter != 1)
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                         "The [directives] section should be the first one in "
                         "the file, otherwise some its settings might not be "
                         "used correctly.");
            }
            eCurrentSection = Section::GENERAL;
        }
        else if (eCurrentSection == Section::GENERAL)
        {
            char *pszKey = nullptr;
            const char *pszValue = CPLParseNameValue(pszLine, &pszKey);
            if (pszKey && pszValue)
            {
                if (strcmp(pszKey, "ignore-env-vars") == 0)
                {
                    gbIgnoreEnvVariables = CPLTestBool(pszValue);
                }
                else
                {
                    CPLError(CE_Warning, CPLE_AppDefined,
                             "Ignoring %s line in [directives] section",
                             pszLine);
                }
            }
            CPLFree(pszKey);
        }
        else if (eCurrentSection == Section::CREDENTIALS)
        {
            if (strncmp(pszLine, "[.", 2) == 0)
            {
                bInSubsection = true;
                osPath.clear();
            }
            else if (bInSubsection)
            {
                char *pszKey = nullptr;
                const char *pszValue = CPLParseNameValue(pszLine, &pszKey);
                if (pszKey && pszValue)
                {
                    if (strcmp(pszKey, "path") == 0)
                    {
                        if (!osPath.empty())
                        {
                            CPLError(
                                CE_Warning, CPLE_AppDefined,
                                "Duplicated 'path' key in the same subsection. "
                                "Ignoring %s=%s",
                                pszKey, pszValue);
                        }
                        else
                        {
                            osPath = pszValue;
                        }
                    }
                    else if (osPath.empty())
                    {
                        CPLError(CE_Warning, CPLE_AppDefined,
                                 "First entry in a credentials subsection "
                                 "should be 'path'.");
                    }
                    else
                    {
                        VSISetPathSpecificOption(osPath.c_str(), pszKey,
                                                 pszValue);
                    }
                }
                CPLFree(pszKey);
            }
            else if (pszLine[0] == '[')
            {
                eCurrentSection = Section::NONE;
            }
            else
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                         "Ignoring content in [credential] section that is not "
                         "in a [.xxxxx] subsection");
            }
        }
        else if (pszLine[0] == '[')
        {
            eCurrentSection = Section::NONE;
        }
        else if (eCurrentSection == Section::CONFIG_OPTIONS)
        {
            char *pszKey = nullptr;
            const char *pszValue = CPLParseNameValue(pszLine, &pszKey);
            if (pszKey && pszValue)
            {
                if (bOverrideEnvVars || gbIgnoreEnvVariables ||
                    getenv(pszKey) == nullptr)
                {
                    CPLDebugOnly("CPL", "Setting configuration option %s=%s",
                                 pszKey, pszValue);
                    CPLSetConfigOption(pszKey, pszValue);
                }
                else
                {
                    CPLDebug("CPL",
                             "Ignoring configuration option %s=%s from "
                             "configuration file as it is already set "
                             "as an environment variable",
                             pszKey, pszValue);
                }
            }
            CPLFree(pszKey);
        }
    }
    VSIFCloseL(fp);
}

/************************************************************************/
/*                CPLLoadConfigOptionsFromPredefinedFiles()             */
/************************************************************************/

/** Load configuration from a set of predefined files.
 *
 * If the environment variable (or configuration option) GDAL_CONFIG_FILE is
 * set, then CPLLoadConfigOptionsFromFile() will be called with the value of
 * this configuration option as the file location.
 *
 * Otherwise, for Unix builds, CPLLoadConfigOptionsFromFile() will be called
 * with ${sysconfdir}/gdal/gdalrc first where ${sysconfdir} evaluates
 * to ${prefix}/etc, unless the \--sysconfdir switch of configure has been
 * invoked.
 *
 * Then CPLLoadConfigOptionsFromFile() will be called with ${HOME}/.gdal/gdalrc
 * on Unix builds (potentially overriding what was loaded with the sysconfdir)
 * or ${USERPROFILE}/.gdal/gdalrc on Windows builds.
 *
 * CPLLoadConfigOptionsFromFile() will be called with bOverrideEnvVars = false,
 * that is the value of environment variables previously set will be used
 * instead of the value set in the configuration files (unless the configuration
 * file contains a leading [directives] section with a "ignore-env-vars=yes"
 * setting).
 *
 * This function is automatically called by GDALDriverManager() constructor
 *
 * @since GDAL 3.3
 */
void CPLLoadConfigOptionsFromPredefinedFiles()
{
    const char *pszFile = CPLGetConfigOption("GDAL_CONFIG_FILE", nullptr);
    if (pszFile != nullptr)
    {
        CPLLoadConfigOptionsFromFile(pszFile, false);
    }
    else
    {
#ifdef SYSCONFDIR
        CPLLoadConfigOptionsFromFile(
            CPLFormFilenameSafe(
                CPLFormFilenameSafe(SYSCONFDIR, "gdal", nullptr).c_str(),
                "gdalrc", nullptr)
                .c_str(),
            false);
#endif

#ifdef _WIN32
        const char *pszHome = CPLGetConfigOption("USERPROFILE", nullptr);
#else
        const char *pszHome = CPLGetConfigOption("HOME", nullptr);
#endif
        if (pszHome != nullptr)
        {
            CPLLoadConfigOptionsFromFile(
                CPLFormFilenameSafe(
                    CPLFormFilenameSafe(pszHome, ".gdal", nullptr).c_str(),
                    "gdalrc", nullptr)
                    .c_str(),
                false);
        }
    }
}

/************************************************************************/
/*                              CPLStat()                               */
/************************************************************************/

/** Same as VSIStat() except it works on "C:" as if it were "C:\". */

int CPLStat(const char *pszPath, VSIStatBuf *psStatBuf)

{
    if (strlen(pszPath) == 2 && pszPath[1] == ':')
    {
        char szAltPath[4] = {pszPath[0], pszPath[1], '\\', '\0'};
        return VSIStat(szAltPath, psStatBuf);
    }

    return VSIStat(pszPath, psStatBuf);
}

/************************************************************************/
/*                            proj_strtod()                             */
/************************************************************************/
static double proj_strtod(char *nptr, char **endptr)

{
    char c = '\0';
    char *cp = nptr;

    // Scan for characters which cause problems with VC++ strtod().
    while ((c = *cp) != '\0')
    {
        if (c == 'd' || c == 'D')
        {
            // Found one, so NUL it out, call strtod(),
            // then restore it and return.
            *cp = '\0';
            const double result = CPLStrtod(nptr, endptr);
            *cp = c;
            return result;
        }
        ++cp;
    }

    // No offending characters, just handle normally.

    return CPLStrtod(nptr, endptr);
}

/************************************************************************/
/*                            CPLDMSToDec()                             */
/************************************************************************/

static const char *sym = "NnEeSsWw";
constexpr double vm[] = {1.0, 0.0166666666667, 0.00027777778};

/** CPLDMSToDec */
double CPLDMSToDec(const char *is)

{
    // Copy string into work space.
    while (isspace(static_cast<unsigned char>(*is)))
        ++is;

    const char *p = is;
    char work[64] = {};
    char *s = work;
    int n = sizeof(work);
    for (; isgraph(*p) && --n;)
        *s++ = *p++;
    *s = '\0';
    // It is possible that a really odd input (like lots of leading
    // zeros) could be truncated in copying into work.  But...
    s = work;
    int sign = *s;

    if (sign == '+' || sign == '-')
        s++;
    else
        sign = '+';

    int nl = 0;
    double v = 0.0;
    for (; nl < 3; nl = n + 1)
    {
        if (!(isdigit(static_cast<unsigned char>(*s)) || *s == '.'))
            break;
        const double tv = proj_strtod(s, &s);
        if (tv == HUGE_VAL)
            return tv;
        switch (*s)
        {
            case 'D':
            case 'd':
                n = 0;
                break;
            case '\'':
                n = 1;
                break;
            case '"':
                n = 2;
                break;
            case 'r':
            case 'R':
                if (nl)
                {
                    return 0.0;
                }
                ++s;
                v = tv;
                goto skip;
            default:
                v += tv * vm[nl];
            skip:
                n = 4;
                continue;
        }
        if (n < nl)
        {
            return 0.0;
        }
        v += tv * vm[n];
        ++s;
    }
    // Postfix sign.
    if (*s && ((p = strchr(sym, *s))) != nullptr)
    {
        sign = (p - sym) >= 4 ? '-' : '+';
        ++s;
    }
    if (sign == '-')
        v = -v;

    return v;
}

/************************************************************************/
/*                            CPLDecToDMS()                             */
/************************************************************************/

/** Translate a decimal degrees value to a DMS string with hemisphere. */

const char *CPLDecToDMS(double dfAngle, const char *pszAxis, int nPrecision)

{
    VALIDATE_POINTER1(pszAxis, "CPLDecToDMS", "");

    if (std::isnan(dfAngle))
        return "Invalid angle";

    const double dfEpsilon = (0.5 / 3600.0) * pow(0.1, nPrecision);
    const double dfABSAngle = std::abs(dfAngle) + dfEpsilon;
    if (dfABSAngle > 361.0)
    {
        return "Invalid angle";
    }

    const int nDegrees = static_cast<int>(dfABSAngle);
    const int nMinutes = static_cast<int>((dfABSAngle - nDegrees) * 60);
    double dfSeconds = dfABSAngle * 3600 - nDegrees * 3600 - nMinutes * 60;

    if (dfSeconds > dfEpsilon * 3600.0)
        dfSeconds -= dfEpsilon * 3600.0;

    const char *pszHemisphere = nullptr;
    if (EQUAL(pszAxis, "Long") && dfAngle < 0.0)
        pszHemisphere = "W";
    else if (EQUAL(pszAxis, "Long"))
        pszHemisphere = "E";
    else if (dfAngle < 0.0)
        pszHemisphere = "S";
    else
        pszHemisphere = "N";

    char szFormat[30] = {};
    CPLsnprintf(szFormat, sizeof(szFormat), "%%3dd%%2d\'%%%d.%df\"%s",
                nPrecision + 3, nPrecision, pszHemisphere);

    static CPL_THREADLOCAL char szBuffer[50] = {};
    CPLsnprintf(szBuffer, sizeof(szBuffer), szFormat, nDegrees, nMinutes,
                dfSeconds);

    return szBuffer;
}

/************************************************************************/
/*                         CPLPackedDMSToDec()                          */
/************************************************************************/

/**
 * Convert a packed DMS value (DDDMMMSSS.SS) into decimal degrees.
 *
 * This function converts a packed DMS angle to seconds. The standard
 * packed DMS format is:
 *
 *  degrees * 1000000 + minutes * 1000 + seconds
 *
 * Example:     angle = 120025045.25 yields
 *              deg = 120
 *              min = 25
 *              sec = 45.25
 *
 * The algorithm used for the conversion is as follows:
 *
 * 1.  The absolute value of the angle is used.
 *
 * 2.  The degrees are separated out:
 *     deg = angle/1000000                    (fractional portion truncated)
 *
 * 3.  The minutes are separated out:
 *     min = (angle - deg * 1000000) / 1000   (fractional portion truncated)
 *
 * 4.  The seconds are then computed:
 *     sec = angle - deg * 1000000 - min * 1000
 *
 * 5.  The total angle in seconds is computed:
 *     sec = deg * 3600.0 + min * 60.0 + sec
 *
 * 6.  The sign of sec is set to that of the input angle.
 *
 * Packed DMS values used by the USGS GCTP package and probably by other
 * software.
 *
 * NOTE: This code does not validate input value. If you give the wrong
 * value, you will get the wrong result.
 *
 * @param dfPacked Angle in packed DMS format.
 *
 * @return Angle in decimal degrees.
 *
 */

double CPLPackedDMSToDec(double dfPacked)
{
    const double dfSign = dfPacked < 0.0 ? -1 : 1;

    double dfSeconds = std::abs(dfPacked);
    double dfDegrees = floor(dfSeconds / 1000000.0);
    dfSeconds -= dfDegrees * 1000000.0;
    const double dfMinutes = floor(dfSeconds / 1000.0);
    dfSeconds -= dfMinutes * 1000.0;
    dfSeconds = dfSign * (dfDegrees * 3600.0 + dfMinutes * 60.0 + dfSeconds);
    dfDegrees = dfSeconds / 3600.0;

    return dfDegrees;
}

/************************************************************************/
/*                         CPLDecToPackedDMS()                          */
/************************************************************************/
/**
 * Convert decimal degrees into packed DMS value (DDDMMMSSS.SS).
 *
 * This function converts a value, specified in decimal degrees into
 * packed DMS angle. The standard packed DMS format is:
 *
 *  degrees * 1000000 + minutes * 1000 + seconds
 *
 * See also CPLPackedDMSToDec().
 *
 * @param dfDec Angle in decimal degrees.
 *
 * @return Angle in packed DMS format.
 *
 */

double CPLDecToPackedDMS(double dfDec)
{
    const double dfSign = dfDec < 0.0 ? -1 : 1;

    dfDec = std::abs(dfDec);
    const double dfDegrees = floor(dfDec);
    const double dfMinutes = floor((dfDec - dfDegrees) * 60.0);
    const double dfSeconds = (dfDec - dfDegrees) * 3600.0 - dfMinutes * 60.0;

    return dfSign * (dfDegrees * 1000000.0 + dfMinutes * 1000.0 + dfSeconds);
}

/************************************************************************/
/*                         CPLStringToComplex()                         */
/************************************************************************/

/** Fetch the real and imaginary part of a serialized complex number */
CPLErr CPL_DLL CPLStringToComplex(const char *pszString, double *pdfReal,
                                  double *pdfImag)

{
    while (*pszString == ' ')
        pszString++;

    char *end;
    *pdfReal = CPLStrtod(pszString, &end);

    int iPlus = -1;
    int iImagEnd = -1;

    if (pszString == end)
    {
        goto error;
    }

    *pdfImag = 0.0;

    for (int i = static_cast<int>(end - pszString);
         i < 100 && pszString[i] != '\0' && pszString[i] != ' '; i++)
    {
        if (pszString[i] == '+')
        {
            if (iPlus != -1)
                goto error;
            iPlus = i;
        }
        if (pszString[i] == '-')
        {
            if (iPlus != -1)
                goto error;
            iPlus = i;
        }
        if (pszString[i] == 'i')
        {
            if (iPlus == -1)
                goto error;
            iImagEnd = i;
        }
    }

    // If we have a "+" or "-" we must also have an "i"
    if ((iPlus == -1) != (iImagEnd == -1))
    {
        goto error;
    }

    // Parse imaginary component, if any
    if (iPlus > -1)
    {
        *pdfImag = CPLStrtod(pszString + iPlus, &end);
    }

    // Check everything remaining is whitespace
    for (; *end != '\0'; end++)
    {
        if (!isspace(*end) && end - pszString != iImagEnd)
        {
            goto error;
        }
    }

    return CE_None;

error:
    CPLError(CE_Failure, CPLE_AppDefined, "Failed to parse number: %s",
             pszString);
    return CE_Failure;
}

/************************************************************************/
/*                           CPLOpenShared()                            */
/************************************************************************/

/**
 * Open a shared file handle.
 *
 * Some operating systems have limits on the number of file handles that can
 * be open at one time.  This function attempts to maintain a registry of
 * already open file handles, and reuse existing ones if the same file
 * is requested by another part of the application.
 *
 * Note that access is only shared for access types "r", "rb", "r+" and
 * "rb+".  All others will just result in direct VSIOpen() calls.  Keep in
 * mind that a file is only reused if the file name is exactly the same.
 * Different names referring to the same file will result in different
 * handles.
 *
 * The VSIFOpen() or VSIFOpenL() function is used to actually open the file,
 * when an existing file handle can't be shared.
 *
 * @param pszFilename the name of the file to open.
 * @param pszAccess the normal fopen()/VSIFOpen() style access string.
 * @param bLargeIn If TRUE VSIFOpenL() (for large files) will be used instead of
 * VSIFOpen().
 *
 * @return a file handle or NULL if opening fails.
 */

FILE *CPLOpenShared(const char *pszFilename, const char *pszAccess,
                    int bLargeIn)

{
    const bool bLarge = CPL_TO_BOOL(bLargeIn);
    CPLMutexHolderD(&hSharedFileMutex);
    const GIntBig nPID = CPLGetPID();

    /* -------------------------------------------------------------------- */
    /*      Is there an existing file we can use?                           */
    /* -------------------------------------------------------------------- */
    const bool bReuse = EQUAL(pszAccess, "rb") || EQUAL(pszAccess, "rb+");

    for (int i = 0; bReuse && i < nSharedFileCount; i++)
    {
        if (strcmp(pasSharedFileList[i].pszFilename, pszFilename) == 0 &&
            !bLarge == !pasSharedFileList[i].bLarge &&
            EQUAL(pasSharedFileList[i].pszAccess, pszAccess) &&
            nPID == pasSharedFileListExtra[i].nPID)
        {
            pasSharedFileList[i].nRefCount++;
            return pasSharedFileList[i].fp;
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Open the file.                                                  */
    /* -------------------------------------------------------------------- */
    FILE *fp = bLarge
                   ? reinterpret_cast<FILE *>(VSIFOpenL(pszFilename, pszAccess))
                   : VSIFOpen(pszFilename, pszAccess);

    if (fp == nullptr)
        return nullptr;

    /* -------------------------------------------------------------------- */
    /*      Add an entry to the list.                                       */
    /* -------------------------------------------------------------------- */
    nSharedFileCount++;

    pasSharedFileList = static_cast<CPLSharedFileInfo *>(
        CPLRealloc(const_cast<CPLSharedFileInfo *>(pasSharedFileList),
                   sizeof(CPLSharedFileInfo) * nSharedFileCount));
    pasSharedFileListExtra = static_cast<CPLSharedFileInfoExtra *>(
        CPLRealloc(const_cast<CPLSharedFileInfoExtra *>(pasSharedFileListExtra),
                   sizeof(CPLSharedFileInfoExtra) * nSharedFileCount));

    pasSharedFileList[nSharedFileCount - 1].fp = fp;
    pasSharedFileList[nSharedFileCount - 1].nRefCount = 1;
    pasSharedFileList[nSharedFileCount - 1].bLarge = bLarge;
    pasSharedFileList[nSharedFileCount - 1].pszFilename =
        CPLStrdup(pszFilename);
    pasSharedFileList[nSharedFileCount - 1].pszAccess = CPLStrdup(pszAccess);
    pasSharedFileListExtra[nSharedFileCount - 1].nPID = nPID;

    return fp;
}

/************************************************************************/
/*                           CPLCloseShared()                           */
/************************************************************************/

/**
 * Close shared file.
 *
 * Dereferences the indicated file handle, and closes it if the reference
 * count has dropped to zero.  A CPLError() is issued if the file is not
 * in the shared file list.
 *
 * @param fp file handle from CPLOpenShared() to deaccess.
 */

void CPLCloseShared(FILE *fp)

{
    CPLMutexHolderD(&hSharedFileMutex);

    /* -------------------------------------------------------------------- */
    /*      Search for matching information.                                */
    /* -------------------------------------------------------------------- */
    int i = 0;
    for (; i < nSharedFileCount && fp != pasSharedFileList[i].fp; i++)
    {
    }

    if (i == nSharedFileCount)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Unable to find file handle %p in CPLCloseShared().", fp);
        return;
    }

    /* -------------------------------------------------------------------- */
    /*      Dereference and return if there are still some references.      */
    /* -------------------------------------------------------------------- */
    if (--pasSharedFileList[i].nRefCount > 0)
        return;

    /* -------------------------------------------------------------------- */
    /*      Close the file, and remove the information.                     */
    /* -------------------------------------------------------------------- */
    if (pasSharedFileList[i].bLarge)
    {
        if (VSIFCloseL(reinterpret_cast<VSILFILE *>(pasSharedFileList[i].fp)) !=
            0)
        {
            CPLError(CE_Failure, CPLE_FileIO, "Error while closing %s",
                     pasSharedFileList[i].pszFilename);
        }
    }
    else
    {
        VSIFClose(pasSharedFileList[i].fp);
    }

    CPLFree(pasSharedFileList[i].pszFilename);
    CPLFree(pasSharedFileList[i].pszAccess);

    nSharedFileCount--;
    memmove(
        const_cast<CPLSharedFileInfo *>(pasSharedFileList + i),
        const_cast<CPLSharedFileInfo *>(pasSharedFileList + nSharedFileCount),
        sizeof(CPLSharedFileInfo));
    memmove(const_cast<CPLSharedFileInfoExtra *>(pasSharedFileListExtra + i),
            const_cast<CPLSharedFileInfoExtra *>(pasSharedFileListExtra +
                                                 nSharedFileCount),
            sizeof(CPLSharedFileInfoExtra));

    if (nSharedFileCount == 0)
    {
        CPLFree(const_cast<CPLSharedFileInfo *>(pasSharedFileList));
        pasSharedFileList = nullptr;
        CPLFree(const_cast<CPLSharedFileInfoExtra *>(pasSharedFileListExtra));
        pasSharedFileListExtra = nullptr;
    }
}

/************************************************************************/
/*                   CPLCleanupSharedFileMutex()                        */
/************************************************************************/

void CPLCleanupSharedFileMutex()
{
    if (hSharedFileMutex != nullptr)
    {
        CPLDestroyMutex(hSharedFileMutex);
        hSharedFileMutex = nullptr;
    }
}

/************************************************************************/
/*                          CPLGetSharedList()                          */
/************************************************************************/

/**
 * Fetch list of open shared files.
 *
 * @param pnCount place to put the count of entries.
 *
 * @return the pointer to the first in the array of shared file info
 * structures.
 */

CPLSharedFileInfo *CPLGetSharedList(int *pnCount)

{
    if (pnCount != nullptr)
        *pnCount = nSharedFileCount;

    return const_cast<CPLSharedFileInfo *>(pasSharedFileList);
}

/************************************************************************/
/*                         CPLDumpSharedList()                          */
/************************************************************************/

/**
 * Report open shared files.
 *
 * Dumps all open shared files to the indicated file handle.  If the
 * file handle is NULL information is sent via the CPLDebug() call.
 *
 * @param fp File handle to write to.
 */

void CPLDumpSharedList(FILE *fp)

{
    if (nSharedFileCount > 0)
    {
        if (fp == nullptr)
            CPLDebug("CPL", "%d Shared files open.", nSharedFileCount);
        else
            fprintf(fp, "%d Shared files open.", nSharedFileCount);
    }

    for (int i = 0; i < nSharedFileCount; i++)
    {
        if (fp == nullptr)
            CPLDebug("CPL", "%2d %d %4s %s", pasSharedFileList[i].nRefCount,
                     pasSharedFileList[i].bLarge,
                     pasSharedFileList[i].pszAccess,
                     pasSharedFileList[i].pszFilename);
        else
            fprintf(fp, "%2d %d %4s %s", pasSharedFileList[i].nRefCount,
                    pasSharedFileList[i].bLarge, pasSharedFileList[i].pszAccess,
                    pasSharedFileList[i].pszFilename);
    }
}

/************************************************************************/
/*                           CPLUnlinkTree()                            */
/************************************************************************/

/** Recursively unlink a directory.
 *
 * @return 0 on successful completion, -1 if function fails.
 */

int CPLUnlinkTree(const char *pszPath)

{
    /* -------------------------------------------------------------------- */
    /*      First, ensure there is such a file.                             */
    /* -------------------------------------------------------------------- */
    VSIStatBufL sStatBuf;

    if (VSIStatL(pszPath, &sStatBuf) != 0)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "It seems no file system object called '%s' exists.", pszPath);

        return -1;
    }

    /* -------------------------------------------------------------------- */
    /*      If it is a simple file, just delete it.                         */
    /* -------------------------------------------------------------------- */
    if (VSI_ISREG(sStatBuf.st_mode))
    {
        if (VSIUnlink(pszPath) != 0)
        {
            CPLError(CE_Failure, CPLE_AppDefined, "Failed to unlink %s.",
                     pszPath);

            return -1;
        }

        return 0;
    }

    /* -------------------------------------------------------------------- */
    /*      If it is a directory recurse then unlink the directory.         */
    /* -------------------------------------------------------------------- */
    else if (VSI_ISDIR(sStatBuf.st_mode))
    {
        char **papszItems = VSIReadDir(pszPath);

        for (int i = 0; papszItems != nullptr && papszItems[i] != nullptr; i++)
        {
            if (papszItems[i][0] == '\0' || EQUAL(papszItems[i], ".") ||
                EQUAL(papszItems[i], ".."))
                continue;

            const std::string osSubPath =
                CPLFormFilenameSafe(pszPath, papszItems[i], nullptr);

            const int nErr = CPLUnlinkTree(osSubPath.c_str());

            if (nErr != 0)
            {
                CSLDestroy(papszItems);
                return nErr;
            }
        }

        CSLDestroy(papszItems);

        if (VSIRmdir(pszPath) != 0)
        {
            CPLError(CE_Failure, CPLE_AppDefined, "Failed to unlink %s.",
                     pszPath);

            return -1;
        }

        return 0;
    }

    /* -------------------------------------------------------------------- */
    /*      otherwise report an error.                                      */
    /* -------------------------------------------------------------------- */
    CPLError(CE_Failure, CPLE_AppDefined,
             "Failed to unlink %s.\nUnrecognised filesystem object.", pszPath);
    return 1000;
}

/************************************************************************/
/*                            CPLCopyFile()                             */
/************************************************************************/

/** Copy a file */
int CPLCopyFile(const char *pszNewPath, const char *pszOldPath)

{
    return VSICopyFile(pszOldPath, pszNewPath, nullptr,
                       static_cast<vsi_l_offset>(-1), nullptr, nullptr,
                       nullptr);
}

/************************************************************************/
/*                            CPLCopyTree()                             */
/************************************************************************/

/** Recursively copy a tree */
int CPLCopyTree(const char *pszNewPath, const char *pszOldPath)

{
    VSIStatBufL sStatBuf;
    if (VSIStatL(pszNewPath, &sStatBuf) == 0)
    {
        CPLError(
            CE_Failure, CPLE_AppDefined,
            "It seems that a file system object called '%s' already exists.",
            pszNewPath);

        return -1;
    }

    if (VSIStatL(pszOldPath, &sStatBuf) != 0)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "It seems no file system object called '%s' exists.",
                 pszOldPath);

        return -1;
    }

    if (VSI_ISDIR(sStatBuf.st_mode))
    {
        if (VSIMkdir(pszNewPath, 0755) != 0)
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "Cannot create directory '%s'.", pszNewPath);

            return -1;
        }

        char **papszItems = VSIReadDir(pszOldPath);

        for (int i = 0; papszItems != nullptr && papszItems[i] != nullptr; i++)
        {
            if (EQUAL(papszItems[i], ".") || EQUAL(papszItems[i], ".."))
                continue;

            const std::string osNewSubPath =
                CPLFormFilenameSafe(pszNewPath, papszItems[i], nullptr);
            const std::string osOldSubPath =
                CPLFormFilenameSafe(pszOldPath, papszItems[i], nullptr);

            const int nErr =
                CPLCopyTree(osNewSubPath.c_str(), osOldSubPath.c_str());

            if (nErr != 0)
            {
                CSLDestroy(papszItems);
                return nErr;
            }
        }
        CSLDestroy(papszItems);

        return 0;
    }
    else if (VSI_ISREG(sStatBuf.st_mode))
    {
        return CPLCopyFile(pszNewPath, pszOldPath);
    }
    else
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Unrecognized filesystem object : '%s'.", pszOldPath);
        return -1;
    }
}

/************************************************************************/
/*                            CPLMoveFile()                             */
/************************************************************************/

/** Move a file */
int CPLMoveFile(const char *pszNewPath, const char *pszOldPath)

{
    if (VSIRename(pszOldPath, pszNewPath) == 0)
        return 0;

    const int nRet = CPLCopyFile(pszNewPath, pszOldPath);

    if (nRet == 0)
    {
        if (VSIUnlink(pszOldPath) != 0)
        {
            CPLError(CE_Warning, CPLE_AppDefined, "Cannot delete '%s'",
                     pszOldPath);
        }
    }
    return nRet;
}

/************************************************************************/
/*                             CPLSymlink()                             */
/************************************************************************/

/** Create a symbolic link */
#ifdef _WIN32
int CPLSymlink(const char *, const char *, CSLConstList)
{
    return -1;
}
#else
int CPLSymlink(const char *pszOldPath, const char *pszNewPath,
               CSLConstList /* papszOptions */)
{
    return symlink(pszOldPath, pszNewPath);
}
#endif

/************************************************************************/
/* ==================================================================== */
/*                              CPLLocaleC                              */
/* ==================================================================== */
/************************************************************************/

//! @cond Doxygen_Suppress
/************************************************************************/
/*                             CPLLocaleC()                             */
/************************************************************************/

CPLLocaleC::CPLLocaleC() : pszOldLocale(nullptr)
{
    if (CPLTestBool(CPLGetConfigOption("GDAL_DISABLE_CPLLOCALEC", "NO")))
        return;

    pszOldLocale = CPLStrdup(CPLsetlocale(LC_NUMERIC, nullptr));
    if (EQUAL(pszOldLocale, "C") || EQUAL(pszOldLocale, "POSIX") ||
        CPLsetlocale(LC_NUMERIC, "C") == nullptr)
    {
        CPLFree(pszOldLocale);
        pszOldLocale = nullptr;
    }
}

/************************************************************************/
/*                            ~CPLLocaleC()                             */
/************************************************************************/

CPLLocaleC::~CPLLocaleC()

{
    if (pszOldLocale == nullptr)
        return;

    CPLsetlocale(LC_NUMERIC, pszOldLocale);
    CPLFree(pszOldLocale);
}

/************************************************************************/
/*                        CPLThreadLocaleCPrivate                       */
/************************************************************************/

#ifdef HAVE_USELOCALE

class CPLThreadLocaleCPrivate
{
    locale_t nNewLocale;
    locale_t nOldLocale;

    CPL_DISALLOW_COPY_ASSIGN(CPLThreadLocaleCPrivate)

  public:
    CPLThreadLocaleCPrivate();
    ~CPLThreadLocaleCPrivate();
};

CPLThreadLocaleCPrivate::CPLThreadLocaleCPrivate()
    : nNewLocale(newlocale(LC_NUMERIC_MASK, "C", nullptr)),
      nOldLocale(uselocale(nNewLocale))
{
}

CPLThreadLocaleCPrivate::~CPLThreadLocaleCPrivate()
{
    uselocale(nOldLocale);
    freelocale(nNewLocale);
}

#elif defined(_MSC_VER)

class CPLThreadLocaleCPrivate
{
    int nOldValConfigThreadLocale;
    char *pszOldLocale;

    CPL_DISALLOW_COPY_ASSIGN(CPLThreadLocaleCPrivate)

  public:
    CPLThreadLocaleCPrivate();
    ~CPLThreadLocaleCPrivate();
};

CPLThreadLocaleCPrivate::CPLThreadLocaleCPrivate()
{
    nOldValConfigThreadLocale = _configthreadlocale(_ENABLE_PER_THREAD_LOCALE);
    pszOldLocale = setlocale(LC_NUMERIC, "C");
    if (pszOldLocale)
        pszOldLocale = CPLStrdup(pszOldLocale);
}

CPLThreadLocaleCPrivate::~CPLThreadLocaleCPrivate()
{
    if (pszOldLocale != nullptr)
    {
        setlocale(LC_NUMERIC, pszOldLocale);
        CPLFree(pszOldLocale);
    }
    _configthreadlocale(nOldValConfigThreadLocale);
}

#else

class CPLThreadLocaleCPrivate
{
    char *pszOldLocale;

    CPL_DISALLOW_COPY_ASSIGN(CPLThreadLocaleCPrivate)

  public:
    CPLThreadLocaleCPrivate();
    ~CPLThreadLocaleCPrivate();
};

CPLThreadLocaleCPrivate::CPLThreadLocaleCPrivate()
    : pszOldLocale(CPLStrdup(CPLsetlocale(LC_NUMERIC, nullptr)))
{
    if (EQUAL(pszOldLocale, "C") || EQUAL(pszOldLocale, "POSIX") ||
        CPLsetlocale(LC_NUMERIC, "C") == nullptr)
    {
        CPLFree(pszOldLocale);
        pszOldLocale = nullptr;
    }
}

CPLThreadLocaleCPrivate::~CPLThreadLocaleCPrivate()
{
    if (pszOldLocale != nullptr)
    {
        CPLsetlocale(LC_NUMERIC, pszOldLocale);
        CPLFree(pszOldLocale);
    }
}

#endif

/************************************************************************/
/*                        CPLThreadLocaleC()                            */
/************************************************************************/

CPLThreadLocaleC::CPLThreadLocaleC() : m_private(new CPLThreadLocaleCPrivate)
{
}

/************************************************************************/
/*                       ~CPLThreadLocaleC()                            */
/************************************************************************/

CPLThreadLocaleC::~CPLThreadLocaleC()

{
    delete m_private;
}

//! @endcond

/************************************************************************/
/*                          CPLsetlocale()                              */
/************************************************************************/

/**
 * Prevents parallel executions of setlocale().
 *
 * Calling setlocale() concurrently from two or more threads is a
 * potential data race. A mutex is used to provide a critical region so
 * that only one thread at a time can be executing setlocale().
 *
 * The return should not be freed, and copied quickly as it may be invalidated
 * by a following next call to CPLsetlocale().
 *
 * @param category See your compiler's documentation on setlocale.
 * @param locale See your compiler's documentation on setlocale.
 *
 * @return See your compiler's documentation on setlocale.
 */
char *CPLsetlocale(int category, const char *locale)
{
    CPLMutexHolder oHolder(&hSetLocaleMutex);
    char *pszRet = setlocale(category, locale);
    if (pszRet == nullptr)
        return pszRet;

    // Make it thread-locale storage.
    return const_cast<char *>(CPLSPrintf("%s", pszRet));
}

/************************************************************************/
/*                       CPLCleanupSetlocaleMutex()                     */
/************************************************************************/

void CPLCleanupSetlocaleMutex(void)
{
    if (hSetLocaleMutex != nullptr)
        CPLDestroyMutex(hSetLocaleMutex);
    hSetLocaleMutex = nullptr;
}

/************************************************************************/
/*                            IsPowerOfTwo()                            */
/************************************************************************/

int CPLIsPowerOfTwo(unsigned int i)
{
    if (i == 0)
        return FALSE;
    return (i & (i - 1)) == 0 ? TRUE : FALSE;
}

/************************************************************************/
/*                          CPLCheckForFile()                           */
/************************************************************************/

/**
 * Check for file existence.
 *
 * The function checks if a named file exists in the filesystem, hopefully
 * in an efficient fashion if a sibling file list is available.   It exists
 * primarily to do faster file checking for functions like GDAL open methods
 * that get a list of files from the target directory.
 *
 * If the sibling file list exists (is not NULL) it is assumed to be a list
 * of files in the same directory as the target file, and it will be checked
 * (case insensitively) for a match.  If a match is found, pszFilename is
 * updated with the correct case and TRUE is returned.
 *
 * If papszSiblingFiles is NULL, a VSIStatL() is used to test for the files
 * existence, and no case insensitive testing is done.
 *
 * @param pszFilename name of file to check for - filename case updated in
 * some cases.
 * @param papszSiblingFiles a list of files in the same directory as
 * pszFilename if available, or NULL. This list should have no path components.
 *
 * @return TRUE if a match is found, or FALSE if not.
 */

int CPLCheckForFile(char *pszFilename, CSLConstList papszSiblingFiles)

{
    /* -------------------------------------------------------------------- */
    /*      Fallback case if we don't have a sibling file list.             */
    /* -------------------------------------------------------------------- */
    if (papszSiblingFiles == nullptr)
    {
        VSIStatBufL sStatBuf;

        return VSIStatExL(pszFilename, &sStatBuf, VSI_STAT_EXISTS_FLAG) == 0;
    }

    /* -------------------------------------------------------------------- */
    /*      We have sibling files, compare the non-path filename portion    */
    /*      of pszFilename too all entries.                                 */
    /* -------------------------------------------------------------------- */
    const CPLString osFileOnly = CPLGetFilename(pszFilename);

    for (int i = 0; papszSiblingFiles[i] != nullptr; i++)
    {
        if (EQUAL(papszSiblingFiles[i], osFileOnly))
        {
            strcpy(pszFilename + strlen(pszFilename) - osFileOnly.size(),
                   papszSiblingFiles[i]);
            return TRUE;
        }
    }

    return FALSE;
}

/************************************************************************/
/*      Stub implementation of zip services if we don't have libz.      */
/************************************************************************/

#if !defined(HAVE_LIBZ)

void *CPLCreateZip(const char *, char **)

{
    CPLError(CE_Failure, CPLE_NotSupported,
             "This GDAL/OGR build does not include zlib and zip services.");
    return nullptr;
}

CPLErr CPLCreateFileInZip(void *, const char *, char **)
{
    return CE_Failure;
}

CPLErr CPLWriteFileInZip(void *, const void *, int)
{
    return CE_Failure;
}

CPLErr CPLCloseFileInZip(void *)
{
    return CE_Failure;
}

CPLErr CPLCloseZip(void *)
{
    return CE_Failure;
}

void *CPLZLibDeflate(const void *, size_t, int, void *, size_t,
                     size_t *pnOutBytes)
{
    if (pnOutBytes != nullptr)
        *pnOutBytes = 0;
    return nullptr;
}

void *CPLZLibInflate(const void *, size_t, void *, size_t, size_t *pnOutBytes)
{
    if (pnOutBytes != nullptr)
        *pnOutBytes = 0;
    return nullptr;
}

#endif /* !defined(HAVE_LIBZ) */

/************************************************************************/
/* ==================================================================== */
/*                          CPLConfigOptionSetter                       */
/* ==================================================================== */
/************************************************************************/

//! @cond Doxygen_Suppress
/************************************************************************/
/*                         CPLConfigOptionSetter()                      */
/************************************************************************/

CPLConfigOptionSetter::CPLConfigOptionSetter(const char *pszKey,
                                             const char *pszValue,
                                             bool bSetOnlyIfUndefined)
    : m_pszKey(CPLStrdup(pszKey)), m_pszOldValue(nullptr),
      m_bRestoreOldValue(false)
{
    const char *pszOldValue = CPLGetThreadLocalConfigOption(pszKey, nullptr);
    if ((bSetOnlyIfUndefined &&
         CPLGetConfigOption(pszKey, nullptr) == nullptr) ||
        !bSetOnlyIfUndefined)
    {
        m_bRestoreOldValue = true;
        if (pszOldValue)
            m_pszOldValue = CPLStrdup(pszOldValue);
        CPLSetThreadLocalConfigOption(pszKey, pszValue);
    }
}

/************************************************************************/
/*                        ~CPLConfigOptionSetter()                      */
/************************************************************************/

CPLConfigOptionSetter::~CPLConfigOptionSetter()
{
    if (m_bRestoreOldValue)
    {
        CPLSetThreadLocalConfigOption(m_pszKey, m_pszOldValue);
        CPLFree(m_pszOldValue);
    }
    CPLFree(m_pszKey);
}

//! @endcond

/************************************************************************/
/*                          CPLIsInteractive()                          */
/************************************************************************/

/** Returns whether the provided file refers to a terminal.
 *
 * This function is a wrapper of the ``isatty()`` POSIX function.
 *
 * @param f File to test. Typically stdin, stdout or stderr
 * @return true if it is an open file referring to a terminal.
 * @since GDAL 3.11
 */
bool CPLIsInteractive(FILE *f)
{
#ifndef _WIN32
    return isatty(static_cast<int>(fileno(f)));
#else
    return _isatty(_fileno(f));
#endif
}

/************************************************************************/
/*                          CPLLockFileStruct                          */
/************************************************************************/

//! @cond Doxygen_Suppress
struct CPLLockFileStruct
{
    std::string osLockFilename{};
    std::atomic<bool> bStop = false;
    CPLJoinableThread *hThread = nullptr;
};

//! @endcond

/************************************************************************/
/*                          CPLLockFileEx()                             */
/************************************************************************/

/** Create and acquire a lock file.
 *
 * Only one caller can acquire the lock file at a time. The O_CREAT|O_EXCL
 * flags of open() are used for that purpose (there might be limitations for
 * network file systems).
 *
 * The lock file is continuously touched by a thread started by this function,
 * to indicate it is still alive. If an existing lock file is found that has
 * not been recently refreshed it will be considered stalled, and will be
 * deleted before attempting to recreate it.
 *
 * This function must be paired with CPLUnlockFileEx().
 *
 * Available options are:
 * <ul>
 * <li>WAIT_TIME=value_in_sec/inf: Maximum amount of time in second that this
 *     function can spend waiting for the lock. If not set, default to infinity.
 * </li>
 * <li>STALLED_DELAY=value_in_sec: Delay in second to consider that an existing
 * lock file that has not been touched since STALLED_DELAY is stalled, and can
 * be re-acquired. Defaults to 10 seconds.
 * </li>
 * <li>VERBOSE_WAIT_MESSAGE=YES/NO: Whether to emit a CE_Warning message while
 * waiting for a busy lock. Default to NO.
 * </li>
 * </ul>

 * @param pszLockFileName Lock file name. The directory must already exist.
 *                        Must not be NULL.
 * @param[out] phLockFileHandle Pointer to at location where to store the lock
 *                              handle that must be passed to CPLUnlockFileEx().
 *                              *phLockFileHandle will be null if the return
 *                              code of that function is not CLFS_OK.
 * @param papszOptions NULL terminated list of strings, or NULL.
 *
 * @return lock file status.
 *
 * @since 3.11
 */
CPLLockFileStatus CPLLockFileEx(const char *pszLockFileName,
                                CPLLockFileHandle *phLockFileHandle,
                                CSLConstList papszOptions)
{
    if (!pszLockFileName || !phLockFileHandle)
        return CLFS_API_MISUSE;

    *phLockFileHandle = nullptr;

    const double dfWaitTime =
        CPLAtof(CSLFetchNameValueDef(papszOptions, "WAIT_TIME", "inf"));
    const double dfStalledDelay =
        CPLAtof(CSLFetchNameValueDef(papszOptions, "STALLED_DELAY", "10"));
    const bool bVerboseWait =
        CPLFetchBool(papszOptions, "VERBOSE_WAIT_MESSAGE", false);

    for (int i = 0; i < 2; ++i)
    {
#ifdef _WIN32
        wchar_t *pwszFilename =
            CPLRecodeToWChar(pszLockFileName, CPL_ENC_UTF8, CPL_ENC_UCS2);
        int fd = _wopen(pwszFilename, _O_CREAT | _O_EXCL, _S_IREAD | _S_IWRITE);
        CPLFree(pwszFilename);
#else
        int fd = open(pszLockFileName, O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
#endif
        if (fd == -1)
        {
            if (errno != EEXIST || i == 1)
            {
                return CLFS_CANNOT_CREATE_LOCK;
            }
            else
            {
                // Wait for the .lock file to have been removed or
                // not refreshed since dfStalledDelay seconds.
                double dfCurWaitTime = dfWaitTime;
                VSIStatBufL sStat;
                while (VSIStatL(pszLockFileName, &sStat) == 0 &&
                       static_cast<double>(sStat.st_mtime) + dfStalledDelay >
                           static_cast<double>(time(nullptr)))
                {
                    if (dfCurWaitTime <= 1e-5)
                        return CLFS_LOCK_BUSY;

                    if (bVerboseWait)
                    {
                        CPLError(CE_Warning, CPLE_AppDefined,
                                 "Waiting for %s to be freed...",
                                 pszLockFileName);
                    }
                    else
                    {
                        CPLDebug("CPL", "Waiting for %s to be freed...",
                                 pszLockFileName);
                    }

                    const double dfPauseDelay = std::min(0.5, dfWaitTime);
                    CPLSleep(dfPauseDelay);
                    dfCurWaitTime -= dfPauseDelay;
                }

                if (VSIUnlink(pszLockFileName) != 0)
                {
                    return CLFS_CANNOT_CREATE_LOCK;
                }
            }
        }
        else
        {
            close(fd);
            break;
        }
    }

    // Touch regularly the lock file to show it is still alive
    struct KeepAliveLockFile
    {
        static void func(void *user_data)
        {
            CPLLockFileHandle hLockFileHandle =
                static_cast<CPLLockFileHandle>(user_data);
            while (!hLockFileHandle->bStop)
            {
                auto f = VSIVirtualHandleUniquePtr(
                    VSIFOpenL(hLockFileHandle->osLockFilename.c_str(), "wb"));
                if (f)
                {
                    f.reset();
                }
                constexpr double REFRESH_DELAY = 0.5;
                CPLSleep(REFRESH_DELAY);
            }
        }
    };

    *phLockFileHandle = new CPLLockFileStruct();
    (*phLockFileHandle)->osLockFilename = pszLockFileName;

    (*phLockFileHandle)->hThread =
        CPLCreateJoinableThread(KeepAliveLockFile::func, *phLockFileHandle);
    if ((*phLockFileHandle)->hThread == nullptr)
    {
        VSIUnlink(pszLockFileName);
        delete *phLockFileHandle;
        *phLockFileHandle = nullptr;
        return CLFS_THREAD_CREATION_FAILED;
    }

    return CLFS_OK;
}

/************************************************************************/
/*                         CPLUnlockFileEx()                            */
/************************************************************************/

/** Release and delete a lock file.
 *
 * This function must be paired with CPLLockFileEx().
 *
 * @param hLockFileHandle Lock handle (value of *phLockFileHandle argument
 *                        set by CPLLockFileEx()), or NULL.
 *
 * @since 3.11
 */
void CPLUnlockFileEx(CPLLockFileHandle hLockFileHandle)
{
    if (hLockFileHandle)
    {
        // Remove .lock file
        hLockFileHandle->bStop = true;
        CPLJoinThread(hLockFileHandle->hThread);
        VSIUnlink(hLockFileHandle->osLockFilename.c_str());

        delete hLockFileHandle;
    }
}

/************************************************************************/
/*                       CPLFormatReadableFileSize()                    */
/************************************************************************/

template <class T>
static std::string CPLFormatReadableFileSizeInternal(T nSizeInBytes)
{
    constexpr T ONE_MEGA_BYTE = 1000 * 1000;
    constexpr T ONE_GIGA_BYTE = 1000 * ONE_MEGA_BYTE;
    constexpr T ONE_TERA_BYTE = 1000 * ONE_GIGA_BYTE;
    constexpr T ONE_PETA_BYTE = 1000 * ONE_TERA_BYTE;
    constexpr T ONE_HEXA_BYTE = 1000 * ONE_PETA_BYTE;

    if (nSizeInBytes > ONE_HEXA_BYTE)
        return CPLSPrintf("%.02f HB", static_cast<double>(nSizeInBytes) /
                                          static_cast<double>(ONE_HEXA_BYTE));

    if (nSizeInBytes > ONE_PETA_BYTE)
        return CPLSPrintf("%.02f PB", static_cast<double>(nSizeInBytes) /
                                          static_cast<double>(ONE_PETA_BYTE));

    if (nSizeInBytes > ONE_TERA_BYTE)
        return CPLSPrintf("%.02f TB", static_cast<double>(nSizeInBytes) /
                                          static_cast<double>(ONE_TERA_BYTE));

    if (nSizeInBytes > ONE_GIGA_BYTE)
        return CPLSPrintf("%.02f GB", static_cast<double>(nSizeInBytes) /
                                          static_cast<double>(ONE_GIGA_BYTE));

    if (nSizeInBytes > ONE_MEGA_BYTE)
        return CPLSPrintf("%.02f MB", static_cast<double>(nSizeInBytes) /
                                          static_cast<double>(ONE_MEGA_BYTE));

    return CPLSPrintf("%03d,%03d bytes", static_cast<int>(nSizeInBytes) / 1000,
                      static_cast<int>(nSizeInBytes) % 1000);
}

/** Return a file size in a human readable way.
 *
 * e.g 1200000 -> "1.20 MB"
 *
 * @since 3.12
 */
std::string CPLFormatReadableFileSize(uint64_t nSizeInBytes)
{
    return CPLFormatReadableFileSizeInternal(nSizeInBytes);
}

/** Return a file size in a human readable way.
 *
 * e.g 1200000 -> "1.20 MB"
 *
 * @since 3.12
 */
std::string CPLFormatReadableFileSize(double dfSizeInBytes)
{
    return CPLFormatReadableFileSizeInternal(dfSizeInBytes);
}

/************************************************************************/
/*                 CPLGetRemainingFileDescriptorCount()                 */
/************************************************************************/

/** \fn CPLGetRemainingFileDescriptorCount()
 *
 * Return the number of file descriptors that can still be opened by the
 * current process.
 *
 * Only implemented on non-Windows operating systems
 *
 * Return a negative value in case of error or not implemented.
 *
 * @since 3.12
 */

#if defined(__FreeBSD__)

int CPLGetRemainingFileDescriptorCount()
{
    struct rlimit limitNumberOfFilesPerProcess;
    if (getrlimit(RLIMIT_NOFILE, &limitNumberOfFilesPerProcess) != 0)
    {
        return -1;
    }
    const int maxNumberOfFilesPerProcess =
        static_cast<int>(limitNumberOfFilesPerProcess.rlim_cur);

    const pid_t pid = getpid();
    int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_FILEDESC,
                  static_cast<int>(pid)};

    size_t len = 0;

    if (sysctl(mib, 4, nullptr, &len, nullptr, 0) == -1)
    {
        return -1;
    }

    return maxNumberOfFilesPerProcess -
           static_cast<int>(len / sizeof(struct kinfo_file));
}

#else

int CPLGetRemainingFileDescriptorCount()
{
#if !defined(_WIN32) && HAVE_GETRLIMIT
    struct rlimit limitNumberOfFilesPerProcess;
    if (getrlimit(RLIMIT_NOFILE, &limitNumberOfFilesPerProcess) != 0)
    {
        return -1;
    }
    const int maxNumberOfFilesPerProcess =
        static_cast<int>(limitNumberOfFilesPerProcess.rlim_cur);

    int countFilesInUse = 0;
    {
        const char *const apszOptions[] = {"NAME_AND_TYPE_ONLY=YES", nullptr};
#ifdef __linux
        VSIDIR *dir = VSIOpenDir("/proc/self/fd", 0, apszOptions);
#else
        // MacOSX
        VSIDIR *dir = VSIOpenDir("/dev/fd", 0, apszOptions);
#endif
        if (dir)
        {
            while (VSIGetNextDirEntry(dir))
                ++countFilesInUse;
            countFilesInUse -= 2;  // do not count . and ..
            VSICloseDir(dir);
        }
    }

    if (countFilesInUse <= 0)
    {
        // Fallback if above method does not work
        for (int fd = 0; fd < maxNumberOfFilesPerProcess; fd++)
        {
            errno = 0;
            if (fcntl(fd, F_GETFD) != -1 || errno != EBADF)
            {
                countFilesInUse++;
            }
        }
    }

    return maxNumberOfFilesPerProcess - countFilesInUse;
#else
    return -1;
#endif
}

#endif