diff options
Diffstat (limited to 'lib/base64.c')
| -rw-r--r-- | lib/base64.c | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/lib/base64.c b/lib/base64.c new file mode 100644 index 00000000..ea0db6b9 --- /dev/null +++ b/lib/base64.c @@ -0,0 +1,153 @@ +/***************************************************************************\ +* * +* BitlBee - An IRC to IM gateway * +* Base64 handling functions. encode_real() is mostly based on the y64 en- * +* coder from libyahoo2. Moving it to a new file because it's getting big. * +* * +* Copyright 2006 Wilmer van der Gaast <wilmer@gaast.net> * +* * +* This program is free software; you can redistribute it and/or modify * +* it under the terms of the GNU General Public License as published by * +* the Free Software Foundation; either version 2 of the License, or * +* (at your option) any later version. * +* * +* This program is distributed in the hope that it will be useful, * +* but WITHOUT ANY WARRANTY; without even the implied warranty of * +* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * +* GNU General Public License for more details. * +* * +* You should have received a copy of the GNU General Public License along * +* with this program; if not, write to the Free Software Foundation, Inc., * +* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. * +* * +\***************************************************************************/ + +#include <glib.h> +#include <string.h> +#include "base64.h" + +static const char real_b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; + +char *tobase64(const char *text) +{ + return base64_encode((const unsigned char *)text, strlen(text)); +} + +char *base64_encode(const unsigned char *in, int len) +{ + char *out; + + out = g_malloc((len + 2) /* the == padding */ + / 3 /* every 3-byte block */ + * 4 /* becomes a 4-byte one */ + + 1); /* and of course, ASCIIZ! */ + + base64_encode_real((unsigned char*) in, len, (unsigned char*) out, real_b64); + + return out; +} + +int base64_encode_real(const unsigned char *in, int inlen, unsigned char *out, const char *b64digits) +{ + int outlen = 0; + + for (; inlen >= 3; inlen -= 3) + { + out[outlen++] = b64digits[in[0] >> 2]; + out[outlen++] = b64digits[((in[0]<<4) & 0x30) | (in[1]>>4)]; + out[outlen++] = b64digits[((in[1]<<2) & 0x3c) | (in[2]>>6)]; + out[outlen++] = b64digits[in[2] & 0x3f]; + in += 3; + } + if (inlen > 0) + { + out[outlen++] = b64digits[in[0] >> 2]; + if (inlen > 1) + { + out[outlen++] = b64digits[((in[0]<<4) & 0x30) | (in[1]>>4)]; + out[outlen++] = b64digits[((in[1]<<2) & 0x3c)]; + } + else + { + out[outlen++] = b64digits[((in[0]<<4) & 0x30)]; + out[outlen++] = b64digits[64]; + } + out[outlen++] = b64digits[64]; + } + out[outlen] = 0; + + return outlen; +} + +/* Just a simple wrapper, but usually not very convenient because of zero + termination. */ +char *frombase64(const char *in) +{ + unsigned char *out; + + base64_decode(in, &out); + + return (char*) out; +} + +/* FIXME: Lookup table stuff is not threadsafe! (But for now BitlBee is not threaded.) */ +int base64_decode(const char *in, unsigned char **out) +{ + static char b64rev[256] = { 0 }; + int len, i; + + /* Create a reverse-lookup for the Base64 sequence. */ + if( b64rev[0] == 0 ) + { + memset( b64rev, 0xff, 256 ); + for( i = 0; i <= 64; i ++ ) + b64rev[(int)real_b64[i]] = i; + } + + len = strlen( in ); + *out = g_malloc( ( len + 6 ) / 4 * 3 ); + len = base64_decode_real( (unsigned char*) in, *out, b64rev ); + *out = g_realloc( *out, len + 1 ); + out[0][len] = 0; /* Zero termination can't hurt. */ + + return len; +} + +int base64_decode_real(const unsigned char *in, unsigned char *out, char *b64rev) +{ + int i, outlen = 0; + + for( i = 0; in[i] && in[i+1] && in[i+2] && in[i+3]; i += 4 ) + { + int sx; + + sx = b64rev[(int)in[i+0]]; + if( sx >= 64 ) + break; + out[outlen] = ( sx << 2 ) & 0xfc; + + sx = b64rev[(int)in[i+1]]; + if( sx >= 64 ) + break; + out[outlen] |= ( sx >> 4 ) & 0x03; + outlen ++; + out[outlen] = ( sx << 4 ) & 0xf0; + + sx = b64rev[(int)in[i+2]]; + if( sx >= 64 ) + break; + out[outlen] |= ( sx >> 2 ) & 0x0f; + outlen ++; + out[outlen] = ( sx << 6 ) & 0xc0; + + sx = b64rev[(int)in[i+3]]; + if( sx >= 64 ) + break; + out[outlen] |= sx; + outlen ++; + } + + /* If sx > 64 the base64 string was damaged. Should we ignore this? */ + + return outlen; +} |