/* vi:set ts=8 sts=4 sw=4 noet:
 *
 * VIM - Vi IMproved	by Bram Moolenaar
 *
 * Do ":help uganda"  in Vim to read copying and usage conditions.
 * Do ":help credits" in Vim to see a list of people who contributed.
 * See README.txt for an overview of the Vim source code.
 */

#include "vim.h"

#if defined(HAVE_WCHAR_H)
#include <wchar.h> /* for towupper() and towlower() */
#endif
static int win_nolbr_chartabsize(win_T *wp, char_u *s, colnr_T col, int *headp);

static unsigned nr2hex(unsigned c);

static int chartab_initialized = FALSE;

/* b_chartab[] is an array of 32 bytes, each bit representing one of the
 * characters 0-255. */
#define SET_CHARTAB(buf, c) (buf)->b_chartab[(unsigned)(c) >> 3] |= (1 << ((c)&0x7))
#define RESET_CHARTAB(buf, c) (buf)->b_chartab[(unsigned)(c) >> 3] &= ~(1 << ((c)&0x7))
#define GET_CHARTAB(buf, c) ((buf)->b_chartab[(unsigned)(c) >> 3] & (1 << ((c)&0x7)))

/* table used below, see init_chartab() for an explanation */
static char_u g_chartab[256];

/*
 * Flags for g_chartab[].
 */
#define CT_CELL_MASK 0x07  /* mask: nr of display cells (1, 2 or 4) */
#define CT_PRINT_CHAR 0x10 /* flag: set for printable chars */
#define CT_ID_CHAR 0x20    /* flag: set for ID chars */
#define CT_FNAME_CHAR 0x40 /* flag: set for file name chars */

/*
 * Fill g_chartab[].  Also fills curbuf->b_chartab[] with flags for keyword
 * characters for current buffer.
 *
 * Depends on the option settings 'iskeyword', 'isident', 'isfname',
 * 'isprint' and 'encoding'.
 *
 * The index in g_chartab[] depends on 'encoding':
 * - For non-multi-byte index with the byte (same as the character).
 * - For DBCS index with the first byte.
 * - For UTF-8 index with the character (when first byte is up to 0x80 it is
 *   the same as the character, if the first byte is 0x80 and above it depends
 *   on further bytes).
 *
 * The contents of g_chartab[]:
 * - The lower two bits, masked by CT_CELL_MASK, give the number of display
 *   cells the character occupies (1 or 2).  Not valid for UTF-8 above 0x80.
 * - CT_PRINT_CHAR bit is set when the character is printable (no need to
 *   translate the character before displaying it).  Note that only DBCS
 *   characters can have 2 display cells and still be printable.
 * - CT_FNAME_CHAR bit is set when the character can be in a file name.
 * - CT_ID_CHAR bit is set when the character can be in an identifier.
 *
 * Return FAIL if 'iskeyword', 'isident', 'isfname' or 'isprint' option has an
 * error, OK otherwise.
 */
int init_chartab(void)
{
  return buf_init_chartab(curbuf, TRUE);
}

int buf_init_chartab(
    buf_T *buf,
    int global) /* FALSE: only set buf->b_chartab[] */
{
  int c;
  int c2;
  char_u *p;
  int i;
  int tilde;
  int do_isalpha;

  if (global)
  {
    /*
	 * Set the default size for printable characters:
	 * From <Space> to '~' is 1 (printable), others are 2 (not printable).
	 * This also inits all 'isident' and 'isfname' flags to FALSE.
	 *
	 * EBCDIC: all chars below ' ' are not printable, all others are
	 * printable.
	 */
    c = 0;
    while (c < ' ')
      g_chartab[c++] = (dy_flags & DY_UHEX) ? 4 : 2;
#ifdef EBCDIC
    while (c < 255)
#else
    while (c <= '~')
#endif
      g_chartab[c++] = 1 + CT_PRINT_CHAR;
    while (c < 256)
    {
      /* UTF-8: bytes 0xa0 - 0xff are printable (latin1) */
      if (enc_utf8 && c >= 0xa0)
        g_chartab[c++] = CT_PRINT_CHAR + 1;
      /* euc-jp characters starting with 0x8e are single width */
      else if (enc_dbcs == DBCS_JPNU && c == 0x8e)
        g_chartab[c++] = CT_PRINT_CHAR + 1;
      /* other double-byte chars can be printable AND double-width */
      else if (enc_dbcs != 0 && MB_BYTE2LEN(c) == 2)
        g_chartab[c++] = CT_PRINT_CHAR + 2;
      else
        /* the rest is unprintable by default */
        g_chartab[c++] = (dy_flags & DY_UHEX) ? 4 : 2;
    }

    /* Assume that every multi-byte char is a filename character. */
    for (c = 1; c < 256; ++c)
      if ((enc_dbcs != 0 && MB_BYTE2LEN(c) > 1) || (enc_dbcs == DBCS_JPNU && c == 0x8e) || (enc_utf8 && c >= 0xa0))
        g_chartab[c] |= CT_FNAME_CHAR;
  }

  /*
     * Init word char flags all to FALSE
     */
  vim_memset(buf->b_chartab, 0, (size_t)32);
  if (enc_dbcs != 0)
    for (c = 0; c < 256; ++c)
    {
      /* double-byte characters are probably word characters */
      if (MB_BYTE2LEN(c) == 2)
        SET_CHARTAB(buf, c);
    }

  /* Walk through the 'isident', 'iskeyword', 'isfname' and 'isprint'
     * options Each option is a list of characters, character numbers or
     * ranges, separated by commas, e.g.: "200-210,x,#-178,-"
     */
  for (i = global ? 0 : 3; i <= 3; ++i)
  {
    if (i == 0)
      p = p_isi; /* first round: 'isident' */
    else if (i == 1)
      p = p_isp; /* second round: 'isprint' */
    else if (i == 2)
      p = p_isf;        /* third round: 'isfname' */
    else                /* i == 3 */
      p = buf->b_p_isk; /* fourth round: 'iskeyword' */

    while (*p)
    {
      tilde = FALSE;
      do_isalpha = FALSE;
      if (*p == '^' && p[1] != NUL)
      {
        tilde = TRUE;
        ++p;
      }
      if (VIM_ISDIGIT(*p))
        c = getdigits(&p);
      else if (has_mbyte)
        c = mb_ptr2char_adv(&p);
      else
        c = *p++;
      c2 = -1;
      if (*p == '-' && p[1] != NUL)
      {
        ++p;
        if (VIM_ISDIGIT(*p))
          c2 = getdigits(&p);
        else if (has_mbyte)
          c2 = mb_ptr2char_adv(&p);
        else
          c2 = *p++;
      }
      if (c <= 0 || c >= 256 || (c2 < c && c2 != -1) || c2 >= 256 || !(*p == NUL || *p == ','))
        return FAIL;

      if (c2 == -1) /* not a range */
      {
        /*
		 * A single '@' (not "@-@"):
		 * Decide on letters being ID/printable/keyword chars with
		 * standard function isalpha(). This takes care of locale for
		 * single-byte characters).
		 */
        if (c == '@')
        {
          do_isalpha = TRUE;
          c = 1;
          c2 = 255;
        }
        else
          c2 = c;
      }
      while (c <= c2)
      {
        /* Use the MB_ functions here, because isalpha() doesn't
		 * work properly when 'encoding' is "latin1" and the locale is
		 * "C".  */
        if (!do_isalpha || MB_ISLOWER(c) || MB_ISUPPER(c))
        {
          if (i == 0) /* (re)set ID flag */
          {
            if (tilde)
              g_chartab[c] &= ~CT_ID_CHAR;
            else
              g_chartab[c] |= CT_ID_CHAR;
          }
          else if (i == 1) /* (re)set printable */
          {
            if ((c < ' '
#ifndef EBCDIC
                 || c > '~'
#endif
                 // For double-byte we keep the cell width, so
                 // that we can detect it from the first byte.
                 ) &&
                !(enc_dbcs && MB_BYTE2LEN(c) == 2))
            {
              if (tilde)
              {
                g_chartab[c] = (g_chartab[c] & ~CT_CELL_MASK) + ((dy_flags & DY_UHEX) ? 4 : 2);
                g_chartab[c] &= ~CT_PRINT_CHAR;
              }
              else
              {
                g_chartab[c] = (g_chartab[c] & ~CT_CELL_MASK) + 1;
                g_chartab[c] |= CT_PRINT_CHAR;
              }
            }
          }
          else if (i == 2) /* (re)set fname flag */
          {
            if (tilde)
              g_chartab[c] &= ~CT_FNAME_CHAR;
            else
              g_chartab[c] |= CT_FNAME_CHAR;
          }
          else /* i == 3 */ /* (re)set keyword flag */
          {
            if (tilde)
              RESET_CHARTAB(buf, c);
            else
              SET_CHARTAB(buf, c);
          }
        }
        ++c;
      }

      c = *p;
      p = skip_to_option_part(p);
      if (c == ',' && *p == NUL)
        /* Trailing comma is not allowed. */
        return FAIL;
    }
  }
  chartab_initialized = TRUE;
  return OK;
}

/*
 * Translate any special characters in buf[bufsize] in-place.
 * The result is a string with only printable characters, but if there is not
 * enough room, not all characters will be translated.
 */
void trans_characters(
    char_u *buf,
    int bufsize)
{
  int len;     /* length of string needing translation */
  int room;    /* room in buffer after string */
  char_u *trs; /* translated character */
  int trs_len; /* length of trs[] */

  len = (int)STRLEN(buf);
  room = bufsize - len;
  while (*buf != 0)
  {
    /* Assume a multi-byte character doesn't need translation. */
    if (has_mbyte && (trs_len = (*mb_ptr2len)(buf)) > 1)
      len -= trs_len;
    else
    {
      trs = transchar_byte(*buf);
      trs_len = (int)STRLEN(trs);
      if (trs_len > 1)
      {
        room -= trs_len - 1;
        if (room <= 0)
          return;
        mch_memmove(buf + trs_len, buf + 1, (size_t)len);
      }
      mch_memmove(buf, trs, (size_t)trs_len);
      --len;
    }
    buf += trs_len;
  }
}

#if defined(FEAT_EVAL) || defined(PROTO)
/*
 * Translate a string into allocated memory, replacing special chars with
 * printable chars.  Returns NULL when out of memory.
 */
char_u *
transstr(char_u *s)
{
  char_u *res;
  char_u *p;
  int l, len, c;
  char_u hexbuf[11];

  if (has_mbyte)
  {
    /* Compute the length of the result, taking account of unprintable
	 * multi-byte characters. */
    len = 0;
    p = s;
    while (*p != NUL)
    {
      if ((l = (*mb_ptr2len)(p)) > 1)
      {
        c = (*mb_ptr2char)(p);
        p += l;
        if (vim_isprintc(c))
          len += l;
        else
        {
          transchar_hex(hexbuf, c);
          len += (int)STRLEN(hexbuf);
        }
      }
      else
      {
        l = byte2cells(*p++);
        if (l > 0)
          len += l;
        else
          len += 4; /* illegal byte sequence */
      }
    }
    res = alloc(len + 1);
  }
  else
    res = alloc(vim_strsize(s) + 1);
  if (res != NULL)
  {
    *res = NUL;
    p = s;
    while (*p != NUL)
    {
      if (has_mbyte && (l = (*mb_ptr2len)(p)) > 1)
      {
        c = (*mb_ptr2char)(p);
        if (vim_isprintc(c))
          STRNCAT(res, p, l); /* append printable multi-byte char */
        else
          transchar_hex(res + STRLEN(res), c);
        p += l;
      }
      else
        STRCAT(res, transchar_byte(*p++));
    }
  }
  return res;
}
#endif

/*
 * Catch 22: g_chartab[] can't be initialized before the options are
 * initialized, and initializing options may cause transchar() to be called!
 * When chartab_initialized == FALSE don't use g_chartab[].
 * Does NOT work for multi-byte characters, c must be <= 255.
 * Also doesn't work for the first byte of a multi-byte, "c" must be a
 * character!
 */
static char_u transchar_buf[7];

char_u *
transchar(int c)
{
  int i;

  i = 0;
  if (IS_SPECIAL(c)) /* special key code, display as ~@ char */
  {
    transchar_buf[0] = '~';
    transchar_buf[1] = '@';
    i = 2;
    c = K_SECOND(c);
  }

  if ((!chartab_initialized && (
#ifdef EBCDIC
                                   (c >= 64 && c < 255)
#else
                                   (c >= ' ' && c <= '~')
#endif
                                       )) ||
      (c < 256 && vim_isprintc_strict(c)))
  {
    /* printable character */
    transchar_buf[i] = c;
    transchar_buf[i + 1] = NUL;
  }
  else
    transchar_nonprint(transchar_buf + i, c);
  return transchar_buf;
}

/*
 * Like transchar(), but called with a byte instead of a character.  Checks
 * for an illegal UTF-8 byte.
 */
char_u *
transchar_byte(int c)
{
  if (enc_utf8 && c >= 0x80)
  {
    transchar_nonprint(transchar_buf, c);
    return transchar_buf;
  }
  return transchar(c);
}

/*
 * Convert non-printable character to two or more printable characters in
 * "buf[]".  "buf" needs to be able to hold five bytes.
 * Does NOT work for multi-byte characters, c must be <= 255.
 */
void transchar_nonprint(char_u *buf, int c)
{
  if (c == NL)
    c = NUL; /* we use newline in place of a NUL */
  else if (c == CAR && get_fileformat(curbuf) == EOL_MAC)
    c = NL; /* we use CR in place of  NL in this case */

  if (dy_flags & DY_UHEX) /* 'display' has "uhex" */
    transchar_hex(buf, c);

#ifdef EBCDIC
  /* For EBCDIC only the characters 0-63 and 255 are not printable */
  else if (CtrlChar(c) != 0 || c == DEL)
#else
  else if (c <= 0x7f)  /* 0x00 - 0x1f and 0x7f */
#endif
  {
    buf[0] = '^';
#ifdef EBCDIC
    if (c == DEL)
      buf[1] = '?'; /* DEL displayed as ^? */
    else
      buf[1] = CtrlChar(c);
#else
    buf[1] = c ^ 0x40; /* DEL displayed as ^? */
#endif

    buf[2] = NUL;
  }
  else if (enc_utf8 && c >= 0x80)
  {
    transchar_hex(buf, c);
  }
#ifndef EBCDIC
  else if (c >= ' ' + 0x80 && c <= '~' + 0x80) /* 0xa0 - 0xfe */
  {
    buf[0] = '|';
    buf[1] = c - 0x80;
    buf[2] = NUL;
  }
#else
  else if (c < 64)
  {
    buf[0] = '~';
    buf[1] = MetaChar(c);
    buf[2] = NUL;
  }
#endif
  else /* 0x80 - 0x9f and 0xff */
  {
    /*
	 * TODO: EBCDIC I don't know what to do with this chars, so I display
	 * them as '~?' for now
	 */
    buf[0] = '~';
#ifdef EBCDIC
    buf[1] = '?'; /* 0xff displayed as ~? */
#else
    buf[1] = (c - 0x80) ^ 0x40; /* 0xff displayed as ~? */
#endif
    buf[2] = NUL;
  }
}

void transchar_hex(char_u *buf, int c)
{
  int i = 0;

  buf[0] = '<';
  if (c > 255)
  {
    buf[++i] = nr2hex((unsigned)c >> 12);
    buf[++i] = nr2hex((unsigned)c >> 8);
  }
  buf[++i] = nr2hex((unsigned)c >> 4);
  buf[++i] = nr2hex((unsigned)c);
  buf[++i] = '>';
  buf[++i] = NUL;
}

/*
 * Convert the lower 4 bits of byte "c" to its hex character.
 * Lower case letters are used to avoid the confusion of <F1> being 0xf1 or
 * function key 1.
 */
static unsigned
nr2hex(unsigned c)
{
  if ((c & 0xf) <= 9)
    return (c & 0xf) + '0';
  return (c & 0xf) - 10 + 'a';
}

/*
 * Return number of display cells occupied by byte "b".
 * Caller must make sure 0 <= b <= 255.
 * For multi-byte mode "b" must be the first byte of a character.
 * A TAB is counted as two cells: "^I".
 * For UTF-8 mode this will return 0 for bytes >= 0x80, because the number of
 * cells depends on further bytes.
 */
int byte2cells(int b)
{
  if (enc_utf8 && b >= 0x80)
    return 0;
  return (g_chartab[b] & CT_CELL_MASK);
}

/*
 * Return number of display cells occupied by character "c".
 * "c" can be a special key (negative number) in which case 3 or 4 is returned.
 * A TAB is counted as two cells: "^I" or four: "<09>".
 */
int char2cells(int c)
{
  if (IS_SPECIAL(c))
    return char2cells(K_SECOND(c)) + 2;
  if (c >= 0x80)
  {
    /* UTF-8: above 0x80 need to check the value */
    if (enc_utf8)
      return utf_char2cells(c);
    /* DBCS: double-byte means double-width, except for euc-jp with first
	 * byte 0x8e */
    if (enc_dbcs != 0 && c >= 0x100)
    {
      if (enc_dbcs == DBCS_JPNU && ((unsigned)c >> 8) == 0x8e)
        return 1;
      return 2;
    }
  }
  return (g_chartab[c & 0xff] & CT_CELL_MASK);
}

/*
 * Return number of display cells occupied by character at "*p".
 * A TAB is counted as two cells: "^I" or four: "<09>".
 */
int ptr2cells(char_u *p)
{
  /* For UTF-8 we need to look at more bytes if the first byte is >= 0x80. */
  if (enc_utf8 && *p >= 0x80)
    return utf_ptr2cells(p);
  /* For DBCS we can tell the cell count from the first byte. */
  return (g_chartab[*p] & CT_CELL_MASK);
}

/*
 * Return the number of character cells string "s" will take on the screen,
 * counting TABs as two characters: "^I".
 */
int vim_strsize(char_u *s)
{
  return vim_strnsize(s, (int)MAXCOL);
}

/*
 * Return the number of character cells string "s[len]" will take on the
 * screen, counting TABs as two characters: "^I".
 */
int vim_strnsize(char_u *s, int len)
{
  int size = 0;

  while (*s != NUL && --len >= 0)
    if (has_mbyte)
    {
      int l = (*mb_ptr2len)(s);

      size += ptr2cells(s);
      s += l;
      len -= l - 1;
    }
    else
      size += byte2cells(*s++);

  return size;
}

/*
 * Return the number of characters 'c' will take on the screen, taking
 * into account the size of a tab.
 * Use a define to make it fast, this is used very often!!!
 * Also see getvcol() below.
 */

#ifdef FEAT_VARTABS
#define RET_WIN_BUF_CHARTABSIZE(wp, buf, p, col)                      \
  if (*(p) == TAB && (!(wp)->w_p_list || lcs_tab1))                   \
  {                                                                   \
    return tabstop_padding(col, (buf)->b_p_ts, (buf)->b_p_vts_array); \
  }                                                                   \
  else                                                                \
    return ptr2cells(p);
#else
#define RET_WIN_BUF_CHARTABSIZE(wp, buf, p, col)    \
  if (*(p) == TAB && (!(wp)->w_p_list || lcs_tab1)) \
  {                                                 \
    int ts;                                         \
    ts = (buf)->b_p_ts;                             \
    return (int)(ts - (col % ts));                  \
  }                                                 \
  else                                              \
    return ptr2cells(p);
#endif

int chartabsize(char_u *p, colnr_T col)
{
  RET_WIN_BUF_CHARTABSIZE(curwin, curbuf, p, col)
}

#ifdef FEAT_LINEBREAK
static int
win_chartabsize(win_T *wp, char_u *p, colnr_T col)
{
  RET_WIN_BUF_CHARTABSIZE(wp, wp->w_buffer, p, col)
}
#endif

/*
 * Return the number of characters the string 's' will take on the screen,
 * taking into account the size of a tab.
 */
int linetabsize(char_u *s)
{
  return linetabsize_col(0, s);
}

/*
 * Like linetabsize(), but starting at column "startcol".
 */
int linetabsize_col(int startcol, char_u *s)
{
  colnr_T col = startcol;
  char_u *line = s; /* pointer to start of line, for breakindent */

  while (*s != NUL)
    col += lbr_chartabsize_adv(line, &s, col);
  return (int)col;
}

/*
 * Like linetabsize(), but for a given window instead of the current one.
 */
int win_linetabsize(win_T *wp, char_u *line, colnr_T len)
{
  colnr_T col = 0;
  char_u *s;

  for (s = line; *s != NUL && (len == MAXCOL || s < line + len);
       MB_PTR_ADV(s))
    col += win_lbr_chartabsize(wp, line, s, col, NULL);
  return (int)col;
}

/*
 * Return TRUE if 'c' is a normal identifier character:
 * Letters and characters from the 'isident' option.
 */
int vim_isIDc(int c)
{
  return (c > 0 && c < 0x100 && (g_chartab[c] & CT_ID_CHAR));
}

/*
 * return TRUE if 'c' is a keyword character: Letters and characters from
 * 'iskeyword' option for the current buffer.
 * For multi-byte characters mb_get_class() is used (builtin rules).
 */
int vim_iswordc(int c)
{
  return vim_iswordc_buf(c, curbuf);
}

int vim_iswordc_buf(int c, buf_T *buf)
{
  if (c >= 0x100)
  {
    if (enc_dbcs != 0)
      return dbcs_class((unsigned)c >> 8, (unsigned)(c & 0xff)) >= 2;
    if (enc_utf8)
      return utf_class_buf(c, buf) >= 2;
    return FALSE;
  }
  return (c > 0 && GET_CHARTAB(buf, c) != 0);
}

/*
 * Just like vim_iswordc() but uses a pointer to the (multi-byte) character.
 */
int vim_iswordp(char_u *p)
{
  return vim_iswordp_buf(p, curbuf);
}

int vim_iswordp_buf(char_u *p, buf_T *buf)
{
  int c = *p;

  if (has_mbyte && MB_BYTE2LEN(c) > 1)
    c = (*mb_ptr2char)(p);
  return vim_iswordc_buf(c, buf);
}

/*
 * return TRUE if 'c' is a valid file-name character
 * Assume characters above 0x100 are valid (multi-byte).
 */
int vim_isfilec(int c)
{
  return (c >= 0x100 || (c > 0 && (g_chartab[c] & CT_FNAME_CHAR)));
}

/*
 * return TRUE if 'c' is a valid file-name character or a wildcard character
 * Assume characters above 0x100 are valid (multi-byte).
 * Explicitly interpret ']' as a wildcard character as mch_has_wildcard("]")
 * returns false.
 */
int vim_isfilec_or_wc(int c)
{
  char_u buf[2];

  buf[0] = (char_u)c;
  buf[1] = NUL;
  return vim_isfilec(c) || c == ']' || mch_has_wildcard(buf);
}

/*
 * Return TRUE if 'c' is a printable character.
 * Assume characters above 0x100 are printable (multi-byte), except for
 * Unicode.
 */
int vim_isprintc(int c)
{
  if (enc_utf8 && c >= 0x100)
    return utf_printable(c);
  return (c >= 0x100 || (c > 0 && (g_chartab[c] & CT_PRINT_CHAR)));
}

/*
 * Strict version of vim_isprintc(c), don't return TRUE if "c" is the head
 * byte of a double-byte character.
 */
int vim_isprintc_strict(int c)
{
  if (enc_dbcs != 0 && c < 0x100 && MB_BYTE2LEN(c) > 1)
    return FALSE;
  if (enc_utf8 && c >= 0x100)
    return utf_printable(c);
  return (c >= 0x100 || (c > 0 && (g_chartab[c] & CT_PRINT_CHAR)));
}

/*
 * like chartabsize(), but also check for line breaks on the screen
 */
int lbr_chartabsize(
    char_u *line UNUSED, /* start of the line */
    unsigned char *s,
    colnr_T col)
{
#ifdef FEAT_LINEBREAK
  if (!curwin->w_p_lbr && *p_sbr == NUL && !curwin->w_p_bri)
  {
#endif
    if (curwin->w_p_wrap)
      return win_nolbr_chartabsize(curwin, s, col, NULL);
    RET_WIN_BUF_CHARTABSIZE(curwin, curbuf, s, col)
#ifdef FEAT_LINEBREAK
  }
  return win_lbr_chartabsize(curwin, line == NULL ? s : line, s, col, NULL);
#endif
}

/*
 * Call lbr_chartabsize() and advance the pointer.
 */
int lbr_chartabsize_adv(
    char_u *line, /* start of the line */
    char_u **s,
    colnr_T col)
{
  int retval;

  retval = lbr_chartabsize(line, *s, col);
  MB_PTR_ADV(*s);
  return retval;
}

/*
 * This function is used very often, keep it fast!!!!
 *
 * If "headp" not NULL, set *headp to the size of what we for 'showbreak'
 * string at start of line.  Warning: *headp is only set if it's a non-zero
 * value, init to 0 before calling.
 */
int win_lbr_chartabsize(
    win_T *wp,
    char_u *line UNUSED, /* start of the line */
    char_u *s,
    colnr_T col,
    int *headp UNUSED)
{
#ifdef FEAT_LINEBREAK
  int c;
  int size;
  colnr_T col2;
  colnr_T col_adj = 0; /* col + screen size of tab */
  colnr_T colmax;
  int added;
  int mb_added = 0;
  int numberextra;
  char_u *ps;
  int tab_corr = (*s == TAB);
  int n;

  /*
     * No 'linebreak', 'showbreak' and 'breakindent': return quickly.
     */
  if (!wp->w_p_lbr && !wp->w_p_bri && *p_sbr == NUL)
#endif
  {
    if (wp->w_p_wrap)
      return win_nolbr_chartabsize(wp, s, col, headp);
    RET_WIN_BUF_CHARTABSIZE(wp, wp->w_buffer, s, col)
  }

#ifdef FEAT_LINEBREAK
  /*
     * First get normal size, without 'linebreak'
     */
  size = win_chartabsize(wp, s, col);
  c = *s;
  if (tab_corr)
    col_adj = size - 1;

  /*
     * If 'linebreak' set check at a blank before a non-blank if the line
     * needs a break here
     */
  if (wp->w_p_lbr && VIM_ISBREAK(c) && !VIM_ISBREAK((int)s[1]) && wp->w_p_wrap && wp->w_width != 0)
  {
    /*
	 * Count all characters from first non-blank after a blank up to next
	 * non-blank after a blank.
	 */
    numberextra = win_col_off(wp);
    col2 = col;
    colmax = (colnr_T)(wp->w_width - numberextra - col_adj);
    if (col >= colmax)
    {
      colmax += col_adj;
      n = colmax + win_col_off2(wp);
      if (n > 0)
        colmax += (((col - colmax) / n) + 1) * n - col_adj;
    }

    for (;;)
    {
      ps = s;
      MB_PTR_ADV(s);
      c = *s;
      if (!(c != NUL && (VIM_ISBREAK(c) || (!VIM_ISBREAK(c) && (col2 == col || !VIM_ISBREAK((int)*ps))))))
        break;

      col2 += win_chartabsize(wp, s, col2);
      if (col2 >= colmax) /* doesn't fit */
      {
        size = colmax - col + col_adj;
        break;
      }
    }
  }
  else if (has_mbyte && size == 2 && MB_BYTE2LEN(*s) > 1 && wp->w_p_wrap && in_win_border(wp, col))
  {
    ++size; /* Count the ">" in the last column. */
    mb_added = 1;
  }

  /*
     * May have to add something for 'breakindent' and/or 'showbreak'
     * string at start of line.
     * Set *headp to the size of what we add.
     */
  added = 0;
  if ((*p_sbr != NUL || wp->w_p_bri) && wp->w_p_wrap && col != 0)
  {
    colnr_T sbrlen = 0;
    int numberwidth = win_col_off(wp);

    numberextra = numberwidth;
    col += numberextra + mb_added;
    if (col >= (colnr_T)wp->w_width)
    {
      col -= wp->w_width;
      numberextra = wp->w_width - (numberextra - win_col_off2(wp));
      if (col >= numberextra && numberextra > 0)
        col %= numberextra;
      if (*p_sbr != NUL)
      {
        sbrlen = (colnr_T)MB_CHARLEN(p_sbr);
        if (col >= sbrlen)
          col -= sbrlen;
      }
      if (col >= numberextra && numberextra > 0)
        col = col % numberextra;
      else if (col > 0 && numberextra > 0)
        col += numberwidth - win_col_off2(wp);

      numberwidth -= win_col_off2(wp);
    }
    if (col == 0 || col + size + sbrlen > (colnr_T)wp->w_width)
    {
      added = 0;
      if (*p_sbr != NUL)
      {
        if (size + sbrlen + numberwidth > (colnr_T)wp->w_width)
        {
          // calculate effective window width
          int width = (colnr_T)wp->w_width - sbrlen - numberwidth;
          int prev_width = col
                               ? ((colnr_T)wp->w_width - (sbrlen + col))
                               : 0;

          if (width <= 0)
            width = (colnr_T)1;
          added += ((size - prev_width) / width) * vim_strsize(p_sbr);
          if ((size - prev_width) % width)
            // wrapped, add another length of 'sbr'
            added += vim_strsize(p_sbr);
        }
        else
          added += vim_strsize(p_sbr);
      }
      if (wp->w_p_bri)
        added += get_breakindent_win(wp, line);

      size += added;
      if (col != 0)
        added = 0;
    }
  }
  if (headp != NULL)
    *headp = added + mb_added;
  return size;
#endif
}

/*
 * Like win_lbr_chartabsize(), except that we know 'linebreak' is off and
 * 'wrap' is on.  This means we need to check for a double-byte character that
 * doesn't fit at the end of the screen line.
 */
static int
win_nolbr_chartabsize(
    win_T *wp,
    char_u *s,
    colnr_T col,
    int *headp)
{
  int n;

  if (*s == TAB && (!wp->w_p_list || lcs_tab1))
  {
#ifdef FEAT_VARTABS
    return tabstop_padding(col, wp->w_buffer->b_p_ts,
                           wp->w_buffer->b_p_vts_array);
#else
    n = wp->w_buffer->b_p_ts;
    return (int)(n - (col % n));
#endif
  }
  n = ptr2cells(s);
  /* Add one cell for a double-width character in the last column of the
     * window, displayed with a ">". */
  if (n == 2 && MB_BYTE2LEN(*s) > 1 && in_win_border(wp, col))
  {
    if (headp != NULL)
      *headp = 1;
    return 3;
  }
  return n;
}

/*
 * Return TRUE if virtual column "vcol" is in the rightmost column of window
 * "wp".
 */
int in_win_border(win_T *wp, colnr_T vcol)
{
  int width1; /* width of first line (after line number) */
  int width2; /* width of further lines */

  if (wp->w_width == 0) /* there is no border */
    return FALSE;
  width1 = wp->w_width - win_col_off(wp);
  if ((int)vcol < width1 - 1)
    return FALSE;
  if ((int)vcol == width1 - 1)
    return TRUE;
  width2 = width1 + win_col_off2(wp);
  if (width2 <= 0)
    return FALSE;
  return ((vcol - width1) % width2 == width2 - 1);
}

/*
 * Get virtual column number of pos.
 *  start: on the first position of this character (TAB, ctrl)
 * cursor: where the cursor is on this character (first char, except for TAB)
 *    end: on the last position of this character (TAB, ctrl)
 *
 * This is used very often, keep it fast!
 */
void getvcol(
    win_T *wp,
    pos_T *pos,
    colnr_T *start,
    colnr_T *cursor,
    colnr_T *end)
{
  colnr_T vcol;
  char_u *ptr;    /* points to current char */
  char_u *posptr; /* points to char at pos->col */
  char_u *line;   /* start of the line */
  int incr;
  int head;
#ifdef FEAT_VARTABS
  int *vts = wp->w_buffer->b_p_vts_array;
#endif
  int ts = wp->w_buffer->b_p_ts;
  int c;

  vcol = 0;
  line = ptr = ml_get_buf(wp->w_buffer, pos->lnum, FALSE);
  if (pos->col == MAXCOL)
    posptr = NULL; /* continue until the NUL */
  else
  {
    /* Special check for an empty line, which can happen on exit, when
	 * ml_get_buf() always returns an empty string. */
    if (*ptr == NUL)
      pos->col = 0;
    posptr = ptr + pos->col;
    if (has_mbyte)
      /* always start on the first byte */
      posptr -= (*mb_head_off)(line, posptr);
  }

  /*
     * This function is used very often, do some speed optimizations.
     * When 'list', 'linebreak', 'showbreak' and 'breakindent' are not set
     * use a simple loop.
     * Also use this when 'list' is set but tabs take their normal size.
     */
  if ((!wp->w_p_list || lcs_tab1 != NUL)
#ifdef FEAT_LINEBREAK
      && !wp->w_p_lbr && *p_sbr == NUL && !wp->w_p_bri
#endif
  )
  {
    for (;;)
    {
      head = 0;
      c = *ptr;
      /* make sure we don't go past the end of the line */
      if (c == NUL)
      {
        incr = 1; /* NUL at end of line only takes one column */
        break;
      }
      /* A tab gets expanded, depending on the current column */
      if (c == TAB)
#ifdef FEAT_VARTABS
        incr = tabstop_padding(vcol, ts, vts);
#else
        incr = ts - (vcol % ts);
#endif
      else
      {
        if (has_mbyte)
        {
          /* For utf-8, if the byte is >= 0x80, need to look at
		     * further bytes to find the cell width. */
          if (enc_utf8 && c >= 0x80)
            incr = utf_ptr2cells(ptr);
          else
            incr = g_chartab[c] & CT_CELL_MASK;

          /* If a double-cell char doesn't fit at the end of a line
		     * it wraps to the next line, it's like this char is three
		     * cells wide. */
          if (incr == 2 && wp->w_p_wrap && MB_BYTE2LEN(*ptr) > 1 && in_win_border(wp, vcol))
          {
            ++incr;
            head = 1;
          }
        }
        else
          incr = g_chartab[c] & CT_CELL_MASK;
      }

      if (posptr != NULL && ptr >= posptr) /* character at pos->col */
        break;

      vcol += incr;
      MB_PTR_ADV(ptr);
    }
  }
  else
  {
    for (;;)
    {
      /* A tab gets expanded, depending on the current column */
      head = 0;
      incr = win_lbr_chartabsize(wp, line, ptr, vcol, &head);
      /* make sure we don't go past the end of the line */
      if (*ptr == NUL)
      {
        incr = 1; /* NUL at end of line only takes one column */
        break;
      }

      if (posptr != NULL && ptr >= posptr) /* character at pos->col */
        break;

      vcol += incr;
      MB_PTR_ADV(ptr);
    }
  }
  if (start != NULL)
    *start = vcol + head;
  if (end != NULL)
    *end = vcol + incr - 1;
  if (cursor != NULL)
  {
    if (*ptr == TAB && (State & NORMAL) && !wp->w_p_list && !virtual_active() && !(VIsual_active && (*p_sel == 'e' || LTOREQ_POS(*pos, VIsual))))
      *cursor = vcol + incr - 1; /* cursor at end */
    else
      *cursor = vcol + head; /* cursor at start */
  }
}

/*
 * Get virtual cursor column in the current window, pretending 'list' is off.
 */
colnr_T
getvcol_nolist(pos_T *posp)
{
  int list_save = curwin->w_p_list;
  colnr_T vcol;

  curwin->w_p_list = FALSE;
  if (posp->coladd)
    getvvcol(curwin, posp, NULL, &vcol, NULL);
  else
    getvcol(curwin, posp, NULL, &vcol, NULL);
  curwin->w_p_list = list_save;
  return vcol;
}

/*
 * Get virtual column in virtual mode.
 */
void getvvcol(
    win_T *wp,
    pos_T *pos,
    colnr_T *start,
    colnr_T *cursor,
    colnr_T *end)
{
  colnr_T col;
  colnr_T coladd;
  colnr_T endadd;
  char_u *ptr;

  if (virtual_active())
  {
    /* For virtual mode, only want one value */
    getvcol(wp, pos, &col, NULL, NULL);

    coladd = pos->coladd;
    endadd = 0;
    /* Cannot put the cursor on part of a wide character. */
    ptr = ml_get_buf(wp->w_buffer, pos->lnum, FALSE);
    if (pos->col < (colnr_T)STRLEN(ptr))
    {
      int c = (*mb_ptr2char)(ptr + pos->col);

      if (c != TAB && vim_isprintc(c))
      {
        endadd = (colnr_T)(char2cells(c) - 1);
        if (coladd > endadd) /* past end of line */
          endadd = 0;
        else
          coladd = 0;
      }
    }
    col += coladd;
    if (start != NULL)
      *start = col;
    if (cursor != NULL)
      *cursor = col;
    if (end != NULL)
      *end = col + endadd;
  }
  else
    getvcol(wp, pos, start, cursor, end);
}

/*
 * Get the leftmost and rightmost virtual column of pos1 and pos2.
 * Used for Visual block mode.
 */
void getvcols(
    win_T *wp,
    pos_T *pos1,
    pos_T *pos2,
    colnr_T *left,
    colnr_T *right)
{
  colnr_T from1, from2, to1, to2;

  if (LT_POSP(pos1, pos2))
  {
    getvvcol(wp, pos1, &from1, NULL, &to1);
    getvvcol(wp, pos2, &from2, NULL, &to2);
  }
  else
  {
    getvvcol(wp, pos2, &from1, NULL, &to1);
    getvvcol(wp, pos1, &from2, NULL, &to2);
  }
  if (from2 < from1)
    *left = from2;
  else
    *left = from1;
  if (to2 > to1)
  {
    if (*p_sel == 'e' && from2 - 1 >= to1)
      *right = from2 - 1;
    else
      *right = to2;
  }
  else
    *right = to1;
}

/*
 * skipwhite: skip over ' ' and '\t'.
 */
char_u *
skipwhite(char_u *q)
{
  char_u *p = q;

  while (VIM_ISWHITE(*p)) /* skip to next non-white */
    ++p;
  return p;
}

/*
 * getwhitecols: return the number of whitespace
 * columns (bytes) at the start of a given line
 */
int getwhitecols_curline()
{
  return getwhitecols(ml_get_curline());
}

int getwhitecols(char_u *p)
{
  return skipwhite(p) - p;
}

/*
 * skip over digits
 */
char_u *
skipdigits(char_u *q)
{
  char_u *p = q;

  while (VIM_ISDIGIT(*p)) /* skip to next non-digit */
    ++p;
  return p;
}

#if defined(PROTO)
/*
 * skip over binary digits
 */
char_u *
skipbin(char_u *q)
{
  char_u *p = q;

  while (vim_isbdigit(*p)) /* skip to next non-digit */
    ++p;
  return p;
}

/*
 * skip over digits and hex characters
 */
char_u *
skiphex(char_u *q)
{
  char_u *p = q;

  while (vim_isxdigit(*p)) /* skip to next non-digit */
    ++p;
  return p;
}
#endif

/*
 * skip to bin digit (or NUL after the string)
 */
char_u *
skiptobin(char_u *q)
{
  char_u *p = q;

  while (*p != NUL && !vim_isbdigit(*p)) /* skip to next digit */
    ++p;
  return p;
}

/*
 * skip to digit (or NUL after the string)
 */
char_u *
skiptodigit(char_u *q)
{
  char_u *p = q;

  while (*p != NUL && !VIM_ISDIGIT(*p)) /* skip to next digit */
    ++p;
  return p;
}

/*
 * skip to hex character (or NUL after the string)
 */
char_u *
skiptohex(char_u *q)
{
  char_u *p = q;

  while (*p != NUL && !vim_isxdigit(*p)) /* skip to next digit */
    ++p;
  return p;
}

/*
 * Variant of isdigit() that can handle characters > 0x100.
 * We don't use isdigit() here, because on some systems it also considers
 * superscript 1 to be a digit.
 * Use the VIM_ISDIGIT() macro for simple arguments.
 */
int vim_isdigit(int c)
{
  return (c >= '0' && c <= '9');
}

/*
 * Variant of isxdigit() that can handle characters > 0x100.
 * We don't use isxdigit() here, because on some systems it also considers
 * superscript 1 to be a digit.
 */
int vim_isxdigit(int c)
{
  return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F');
}

/*
 * Corollary of vim_isdigit and vim_isxdigit() that can handle
 * characters > 0x100.
 */
int vim_isbdigit(int c)
{
  return (c == '0' || c == '1');
}

/*
 * Vim's own character class functions.  These exist because many library
 * islower()/toupper() etc. do not work properly: they crash when used with
 * invalid values or can't handle latin1 when the locale is C.
 * Speed is most important here.
 */
#define LATIN1LOWER 'l'
#define LATIN1UPPER 'U'

static char_u latin1flags[257] = "                                                                 UUUUUUUUUUUUUUUUUUUUUUUUUU      llllllllllllllllllllllllll                                                                     UUUUUUUUUUUUUUUUUUUUUUU UUUUUUUllllllllllllllllllllllll llllllll";
static char_u latin1upper[257] = "                                 !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`ABCDEFGHIJKLMNOPQRSTUVWXYZ{|}~\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xf7\xd8\xd9\xda\xdb\xdc\xdd\xde\xff";
static char_u latin1lower[257] = "                                 !\"#$%&'()*+,-./0123456789:;<=>?@abcdefghijklmnopqrstuvwxyz[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xd7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff";

int vim_islower(int c)
{
  if (c <= '@')
    return FALSE;
  if (c >= 0x80)
  {
    if (enc_utf8)
      return utf_islower(c);
    if (c >= 0x100)
    {
#ifdef HAVE_ISWLOWER
      if (has_mbyte)
        return iswlower(c);
#endif
      /* islower() can't handle these chars and may crash */
      return FALSE;
    }
    if (enc_latin1like)
      return (latin1flags[c] & LATIN1LOWER) == LATIN1LOWER;
  }
  return islower(c);
}

int vim_isupper(int c)
{
  if (c <= '@')
    return FALSE;
  if (c >= 0x80)
  {
    if (enc_utf8)
      return utf_isupper(c);
    if (c >= 0x100)
    {
#ifdef HAVE_ISWUPPER
      if (has_mbyte)
        return iswupper(c);
#endif
      /* islower() can't handle these chars and may crash */
      return FALSE;
    }
    if (enc_latin1like)
      return (latin1flags[c] & LATIN1UPPER) == LATIN1UPPER;
  }
  return isupper(c);
}

int vim_toupper(int c)
{
  if (c <= '@')
    return c;
  if (c >= 0x80 || !(cmp_flags & CMP_KEEPASCII))
  {
    if (enc_utf8)
      return utf_toupper(c);
    if (c >= 0x100)
    {
#ifdef HAVE_TOWUPPER
      if (has_mbyte)
        return towupper(c);
#endif
      /* toupper() can't handle these chars and may crash */
      return c;
    }
    if (enc_latin1like)
      return latin1upper[c];
  }
  if (c < 0x80 && (cmp_flags & CMP_KEEPASCII))
    return TOUPPER_ASC(c);
  return TOUPPER_LOC(c);
}

int vim_tolower(int c)
{
  if (c <= '@')
    return c;
  if (c >= 0x80 || !(cmp_flags & CMP_KEEPASCII))
  {
    if (enc_utf8)
      return utf_tolower(c);
    if (c >= 0x100)
    {
#ifdef HAVE_TOWLOWER
      if (has_mbyte)
        return towlower(c);
#endif
      /* tolower() can't handle these chars and may crash */
      return c;
    }
    if (enc_latin1like)
      return latin1lower[c];
  }
  if (c < 0x80 && (cmp_flags & CMP_KEEPASCII))
    return TOLOWER_ASC(c);
  return TOLOWER_LOC(c);
}

/*
 * skiptowhite: skip over text until ' ' or '\t' or NUL.
 */
char_u *
skiptowhite(char_u *p)
{
  while (*p != ' ' && *p != '\t' && *p != NUL)
    ++p;
  return p;
}

/*
 * skiptowhite_esc: Like skiptowhite(), but also skip escaped chars
 */
char_u *
skiptowhite_esc(char_u *p)
{
  while (*p != ' ' && *p != '\t' && *p != NUL)
  {
    if ((*p == '\\' || *p == Ctrl_V) && *(p + 1) != NUL)
      ++p;
    ++p;
  }
  return p;
}

/*
 * Getdigits: Get a number from a string and skip over it.
 * Note: the argument is a pointer to a char_u pointer!
 */
long getdigits(char_u **pp)
{
  char_u *p;
  long retval;

  p = *pp;
  retval = atol((char *)p);
  if (*p == '-') /* skip negative sign */
    ++p;
  p = skipdigits(p); /* skip to next non-digit */
  *pp = p;
  return retval;
}

/*
 * Return TRUE if "lbuf" is empty or only contains blanks.
 */
int vim_isblankline(char_u *lbuf)
{
  char_u *p;

  p = skipwhite(lbuf);
  return (*p == NUL || *p == '\r' || *p == '\n');
}

/*
 * Convert a string into a long and/or unsigned long, taking care of
 * hexadecimal, octal, and binary numbers.  Accepts a '-' sign.
 * If "prep" is not NULL, returns a flag to indicate the type of the number:
 *  0	    decimal
 *  '0'	    octal
 *  'B'	    bin
 *  'b'	    bin
 *  'X'	    hex
 *  'x'	    hex
 * If "len" is not NULL, the length of the number in characters is returned.
 * If "nptr" is not NULL, the signed result is returned in it.
 * If "unptr" is not NULL, the unsigned result is returned in it.
 * If "what" contains STR2NR_BIN recognize binary numbers
 * If "what" contains STR2NR_OCT recognize octal numbers
 * If "what" contains STR2NR_HEX recognize hex numbers
 * If "what" contains STR2NR_FORCE always assume bin/oct/hex.
 * If maxlen > 0, check at a maximum maxlen chars.
 * If strict is TRUE, check the number strictly. return *len = 0 if fail.
 */
void vim_str2nr(
    char_u *start,
    int *prep,           // return: type of number 0 = decimal, 'x'
                         // or 'X' is hex, '0' = octal, 'b' or 'B'
                         // is bin
    int *len,            // return: detected length of number
    int what,            // what numbers to recognize
    varnumber_T *nptr,   // return: signed result
    uvarnumber_T *unptr, // return: unsigned result
    int maxlen,          // max length of string to check
    int strict)          // check strictly
{
  char_u *ptr = start;
  int pre = 0; // default is decimal
  int negative = FALSE;
  uvarnumber_T un = 0;
  int n;

  if (len != NULL)
    *len = 0;

  if (ptr[0] == '-')
  {
    negative = TRUE;
    ++ptr;
  }

  /* Recognize hex, octal, and bin. */
  if (ptr[0] == '0' && ptr[1] != '8' && ptr[1] != '9' && (maxlen == 0 || maxlen > 1))
  {
    pre = ptr[1];
    if ((what & STR2NR_HEX) && (pre == 'X' || pre == 'x') && vim_isxdigit(ptr[2]) && (maxlen == 0 || maxlen > 2))
      /* hexadecimal */
      ptr += 2;
    else if ((what & STR2NR_BIN) && (pre == 'B' || pre == 'b') && vim_isbdigit(ptr[2]) && (maxlen == 0 || maxlen > 2))
      /* binary */
      ptr += 2;
    else
    {
      /* decimal or octal, default is decimal */
      pre = 0;
      if (what & STR2NR_OCT)
      {
        /* Don't interpret "0", "08" or "0129" as octal. */
        for (n = 1; n != maxlen && VIM_ISDIGIT(ptr[n]); ++n)
        {
          if (ptr[n] > '7')
          {
            pre = 0; /* can't be octal */
            break;
          }
          pre = '0'; /* assume octal */
        }
      }
    }
  }

  // Do the conversion manually to avoid sscanf() quirks.
  n = 1;
  if (pre == 'B' || pre == 'b' || what == STR2NR_BIN + STR2NR_FORCE)
  {
    /* bin */
    if (pre != 0)
      n += 2; /* skip over "0b" */
    while ('0' <= *ptr && *ptr <= '1')
    {
      /* avoid ubsan error for overflow */
      if (un <= UVARNUM_MAX / 2)
        un = 2 * un + (uvarnumber_T)(*ptr - '0');
      else
        un = UVARNUM_MAX;
      ++ptr;
      if (n++ == maxlen)
        break;
    }
  }
  else if (pre == '0' || what == STR2NR_OCT + STR2NR_FORCE)
  {
    /* octal */
    while ('0' <= *ptr && *ptr <= '7')
    {
      /* avoid ubsan error for overflow */
      if (un <= UVARNUM_MAX / 8)
        un = 8 * un + (uvarnumber_T)(*ptr - '0');
      else
        un = UVARNUM_MAX;
      ++ptr;
      if (n++ == maxlen)
        break;
    }
  }
  else if (pre != 0 || what == STR2NR_HEX + STR2NR_FORCE)
  {
    /* hex */
    if (pre != 0)
      n += 2; /* skip over "0x" */
    while (vim_isxdigit(*ptr))
    {
      /* avoid ubsan error for overflow */
      if (un <= UVARNUM_MAX / 16)
        un = 16 * un + (uvarnumber_T)hex2nr(*ptr);
      else
        un = UVARNUM_MAX;
      ++ptr;
      if (n++ == maxlen)
        break;
    }
  }
  else
  {
    /* decimal */
    while (VIM_ISDIGIT(*ptr))
    {
      uvarnumber_T digit = (uvarnumber_T)(*ptr - '0');

      /* avoid ubsan error for overflow */
      if (un < UVARNUM_MAX / 10 || (un == UVARNUM_MAX / 10 && digit <= UVARNUM_MAX % 10))
        un = 10 * un + digit;
      else
        un = UVARNUM_MAX;
      ++ptr;
      if (n++ == maxlen)
        break;
    }
  }
  // Check for an alpha-numeric character immediately following, that is
  // most likely a typo.
  if (strict && n - 1 != maxlen && ASCII_ISALNUM(*ptr))
    return;

  if (prep != NULL)
    *prep = pre;
  if (len != NULL)
    *len = (int)(ptr - start);
  if (nptr != NULL)
  {
    if (negative) /* account for leading '-' for decimal numbers */
    {
      /* avoid ubsan error for overflow */
      if (un > VARNUM_MAX)
        *nptr = VARNUM_MIN;
      else
        *nptr = -(varnumber_T)un;
    }
    else
    {
      if (un > VARNUM_MAX)
        un = VARNUM_MAX;
      *nptr = (varnumber_T)un;
    }
  }
  if (unptr != NULL)
    *unptr = un;
}

/*
 * Return the value of a single hex character.
 * Only valid when the argument is '0' - '9', 'A' - 'F' or 'a' - 'f'.
 */
int hex2nr(int c)
{
  if (c >= 'a' && c <= 'f')
    return c - 'a' + 10;
  if (c >= 'A' && c <= 'F')
    return c - 'A' + 10;
  return c - '0';
}

/*
 * Return TRUE if "str" starts with a backslash that should be removed.
 * For MS-DOS, MSWIN and OS/2 this is only done when the character after the
 * backslash is not a normal file name character.
 * '$' is a valid file name character, we don't remove the backslash before
 * it.  This means it is not possible to use an environment variable after a
 * backslash.  "C:\$VIM\doc" is taken literally, only "$VIM\doc" works.
 * Although "\ name" is valid, the backslash in "Program\ files" must be
 * removed.  Assume a file name doesn't start with a space.
 * For multi-byte names, never remove a backslash before a non-ascii
 * character, assume that all multi-byte characters are valid file name
 * characters.
 */
int rem_backslash(char_u *str)
{
#ifdef BACKSLASH_IN_FILENAME
  return (str[0] == '\\' && str[1] < 0x80 && (str[1] == ' ' || (str[1] != NUL && str[1] != '*' && str[1] != '?' && !vim_isfilec(str[1]))));
#else
  return (str[0] == '\\' && str[1] != NUL);
#endif
}

/*
 * Halve the number of backslashes in a file name argument.
 * For MS-DOS we only do this if the character after the backslash
 * is not a normal file character.
 */
void backslash_halve(char_u *p)
{
  for (; *p; ++p)
    if (rem_backslash(p))
      STRMOVE(p, p + 1);
}

/*
 * backslash_halve() plus save the result in allocated memory.
 */
char_u *
backslash_halve_save(char_u *p)
{
  char_u *res;

  res = vim_strsave(p);
  if (res == NULL)
    return p;
  backslash_halve(res);
  return res;
}

#if (defined(EBCDIC) && defined(FEAT_POSTSCRIPT)) || defined(PROTO)
/*
 * Table for EBCDIC to ASCII conversion unashamedly taken from xxd.c!
 * The first 64 entries have been added to map control characters defined in
 * ascii.h
 */
static char_u ebcdic2ascii_tab[256] =
    {
        0000, 0001, 0002, 0003, 0004, 0011, 0006, 0177,
        0010, 0011, 0012, 0013, 0014, 0015, 0016, 0017,
        0020, 0021, 0022, 0023, 0024, 0012, 0010, 0027,
        0030, 0031, 0032, 0033, 0033, 0035, 0036, 0037,
        0040, 0041, 0042, 0043, 0044, 0045, 0046, 0047,
        0050, 0051, 0052, 0053, 0054, 0055, 0056, 0057,
        0060, 0061, 0062, 0063, 0064, 0065, 0066, 0067,
        0070, 0071, 0072, 0073, 0074, 0075, 0076, 0077,
        0040, 0240, 0241, 0242, 0243, 0244, 0245, 0246,
        0247, 0250, 0325, 0056, 0074, 0050, 0053, 0174,
        0046, 0251, 0252, 0253, 0254, 0255, 0256, 0257,
        0260, 0261, 0041, 0044, 0052, 0051, 0073, 0176,
        0055, 0057, 0262, 0263, 0264, 0265, 0266, 0267,
        0270, 0271, 0313, 0054, 0045, 0137, 0076, 0077,
        0272, 0273, 0274, 0275, 0276, 0277, 0300, 0301,
        0302, 0140, 0072, 0043, 0100, 0047, 0075, 0042,
        0303, 0141, 0142, 0143, 0144, 0145, 0146, 0147,
        0150, 0151, 0304, 0305, 0306, 0307, 0310, 0311,
        0312, 0152, 0153, 0154, 0155, 0156, 0157, 0160,
        0161, 0162, 0136, 0314, 0315, 0316, 0317, 0320,
        0321, 0345, 0163, 0164, 0165, 0166, 0167, 0170,
        0171, 0172, 0322, 0323, 0324, 0133, 0326, 0327,
        0330, 0331, 0332, 0333, 0334, 0335, 0336, 0337,
        0340, 0341, 0342, 0343, 0344, 0135, 0346, 0347,
        0173, 0101, 0102, 0103, 0104, 0105, 0106, 0107,
        0110, 0111, 0350, 0351, 0352, 0353, 0354, 0355,
        0175, 0112, 0113, 0114, 0115, 0116, 0117, 0120,
        0121, 0122, 0356, 0357, 0360, 0361, 0362, 0363,
        0134, 0237, 0123, 0124, 0125, 0126, 0127, 0130,
        0131, 0132, 0364, 0365, 0366, 0367, 0370, 0371,
        0060, 0061, 0062, 0063, 0064, 0065, 0066, 0067,
        0070, 0071, 0372, 0373, 0374, 0375, 0376, 0377};

/*
 * Convert a buffer worth of characters from EBCDIC to ASCII.  Only useful if
 * wanting 7-bit ASCII characters out the other end.
 */
void ebcdic2ascii(char_u *buffer, int len)
{
  int i;

  for (i = 0; i < len; i++)
    buffer[i] = ebcdic2ascii_tab[buffer[i]];
}
#endif