#include "first.h" #include "base64.h" /* reverse mapping: * >= 0: base64 value * -1: invalid character * -2: skip character (whitespace/control) * -3: padding */ /* BASE64_STANDARD: "A-Z a-z 0-9 + /" maps to 0-63, pad with "=" */ static const char base64_standard_table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; static const signed char base64_standard_reverse_table[] = { /* 0 1 2 3 4 5 6 7 8 9 A B C D E F */ -1, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, /* 0x00 - 0x0F */ -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, /* 0x10 - 0x1F */ -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, /* 0x20 - 0x2F */ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -3, -1, -1, /* 0x30 - 0x3F */ -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 0x40 - 0x4F */ 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, /* 0x50 - 0x5F */ -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 0x60 - 0x6F */ 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, /* 0x70 - 0x7F */ }; /* BASE64_URL: "A-Z a-z 0-9 - _" maps to 0-63, pad with "=" */ static const char base64_url_table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_="; static const signed char base64_url_reverse_table[] = { /* 0 1 2 3 4 5 6 7 8 9 A B C D E F */ -1, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, /* 0x00 - 0x0F */ -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, /* 0x10 - 0x1F */ -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, /* 0x20 - 0x2F */ 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -3, -1, -1, /* 0x30 - 0x3F */ -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 0x40 - 0x4F */ 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, 63, /* 0x50 - 0x5F */ -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 0x60 - 0x6F */ 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, /* 0x70 - 0x7F */ }; size_t li_base64_dec(unsigned char * const result, const size_t out_length, const char * const in, const size_t in_length, const base64_charset charset) { const unsigned char *un = (const unsigned char *)in; const unsigned char * const end = un + in_length; const signed char * const base64_reverse_table = (charset) ? base64_url_reverse_table /* BASE64_URL */ : base64_standard_reverse_table; /* BASE64_STANDARD */ int_fast32_t ch = 0; int_fast32_t out4 = 0; size_t i = 0; size_t out_pos = 0; for (; un < end; ++un) { ch = (*un < 128) ? base64_reverse_table[*un] : -1; if (__builtin_expect( (ch < 0), 0)) { /* skip formatted base64; skip whitespace ('\r' '\n' '\t' ' ')*/ if (-2 == ch) /*(loose check; skip ' ', all ctrls not \127 or \0)*/ continue; /* skip character */ break; } out4 = (out4 << 6) | ch; if ((++i & 3) == 0) { result[out_pos] = (out4 >> 16) & 0xFF; result[out_pos+1] = (out4 >> 8) & 0xFF; result[out_pos+2] = (out4 ) & 0xFF; out_pos += 3; out4 = 0; } } /* permit base64 string ending with pad chars (ch == -3); not checking * for one or two pad chars + optional whitespace reaches in_length) */ /* permit base64 string truncated before in_length (*un == '\0') */ switch (un == end || ch == -3 || *un != '\0' ? (i & 3) : 1) { case 3: result[out_pos++] = (out4 >> 10); out4 <<= 2; __attribute_fallthrough__ case 2: result[out_pos++] = (out4 >> 4) & 0xFF; __attribute_fallthrough__ case 0: force_assert(out_pos <= out_length); return out_pos; case 1: /* pad char or str end can only come after 2+ base64 chars */ default: return 0; /* invalid character, abort */ } } size_t li_base64_enc(char * const restrict out, const size_t out_length, const unsigned char * const restrict in, const size_t in_length, const base64_charset charset, const int pad) { size_t i; size_t out_pos = 0; uint_fast32_t v; const char* const base64_table = (charset) ? base64_url_table /* BASE64_URL */ : base64_standard_table; /* BASE64_STANDARD */ const char padchar = base64_table[64]; /* padding char */ /* check overflows */ /* 1073741823 is max num full_tuples to avoid overflow in uint32_t; * and (1 GB - 1) is ridiculously large for base64-encoded data */ force_assert(in_length <= 3221225469); /* (3221225469+2) / 3 * 4 < UINT32_MAX */ force_assert((in_length+2)/3*4 <= out_length); for (i = 2; i < in_length; i += 3) { v = (in[i-2] << 16) | (in[i-1] << 8) | in[i]; out[out_pos+0] = base64_table[(v >> 18) & 0x3f]; out[out_pos+1] = base64_table[(v >> 12) & 0x3f]; out[out_pos+2] = base64_table[(v >> 6) & 0x3f]; out[out_pos+3] = base64_table[(v ) & 0x3f]; out_pos += 4; } switch (in_length - (i-2)) { case 0: default: break; case 1: { /* pretend in[i-1] = in[i] = 0, don't write last two (out_pos+3, out_pos+2) characters */ v = (in[i-2] << 4); out[out_pos+0] = base64_table[(v >> 6) & 0x3f]; out[out_pos+1] = base64_table[(v ) & 0x3f]; if (pad) { out[out_pos+2] = out[out_pos+3] = padchar; out_pos += 4; } else out_pos += 2; } break; case 2: { /* pretend in[i] = 0, don't write last (out_pos+3) character */ v = (in[i-2] << 10) | (in[i-1] << 2); out[out_pos+0] = base64_table[(v >> 12) & 0x3f]; out[out_pos+1] = base64_table[(v >> 6) & 0x3f]; out[out_pos+2] = base64_table[(v ) & 0x3f]; if (pad) { out[out_pos+3] = padchar; out_pos += 4; } else out_pos += 3; } break; } return out_pos; } char* buffer_append_base64_enc(buffer *out, const unsigned char* in, size_t in_length, base64_charset charset, int pad) { const size_t reserve = (in_length+2)/3*4; char * const result = buffer_string_prepare_append(out, reserve); const size_t out_pos = li_base64_enc(result, reserve, in, in_length, charset, pad); buffer_commit(out, out_pos); return result; } unsigned char* buffer_append_base64_decode(buffer *out, const char* in, size_t in_length, base64_charset charset) { const size_t reserve = 3*(in_length/4) + 3; unsigned char * const result = (unsigned char *) buffer_string_prepare_append(out, reserve); const size_t out_pos = li_base64_dec(result, reserve, in, in_length, charset); buffer_commit(out, out_pos); return (out_pos || !in_length) ? result : NULL; }