/** @file
Parser: base64 functions impl.
Copyright (c) 2001-2026 Art. Lebedev Studio (https://www.artlebedev.com)
Authors: Konstantin Morshnev <moko@design.ru>, Alexandr Petrosian <paf@design.ru>
*/
#include "pa_base64.h"
#include "pa_common.h"
volatile const char * IDENT_PA_BASE64_C="$Id: pa_base64.C,v 1.15 2026/04/25 13:38:46 moko Exp $" IDENT_PA_BASE64_H;
/*
* BASE64 part inspired by g_mime_utils
* Authors: Michael Zucchi <notzed@ximian.com>
* Jeffrey Stedfast <fejj@ximian.com>
*
* Copyright 2000-2004 Ximian, Inc. (www.ximian.com)
*
* 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., 59 Temple Street #330, Boston, MA 02111-1307, USA.
*
*/
static const char *base64_alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const char *base64_alphabet_url_safe = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
Base64Options::Base64Options(bool awrap): strict(false), wrap(awrap), pad(true), abc(base64_alphabet) {}
void Base64Options::set_url_safe_abc() {
abc = base64_alphabet_url_safe;
}
#define BASE64_GROUPS_IN_LINE 19
static size_t pa_base64_encode(const uchar *in, size_t inlen, uchar *out, Base64Options options) {
const uchar *inptr = in;
uchar *outptr = out;
const uchar *abc = (const uchar *)options.abc;
if (inlen > 2) {
const uchar *inend = in + inlen - 2;
int already=0;
while (inptr < inend) {
int c1 = *inptr++;
int c2 = *inptr++;
int c3 = *inptr++;
*outptr++ = abc[c1 >> 2];
*outptr++ = abc[(c2 >> 4) | ((c1 & 0x3) << 4)];
*outptr++ = abc[((c2 & 0x0f) << 2) | (c3 >> 6)];
*outptr++ = abc[c3 & 0x3f];
if ((++already) >= BASE64_GROUPS_IN_LINE && options.wrap) {
*outptr++ = '\n';
already = 0;
}
}
inlen = 2 - (inptr - inend);
}
if (inlen == 2) {
int c1 = *inptr++;
int c2 = *inptr++;
outptr[0] = abc[c1 >> 2];
outptr[1] = abc[c2 >> 4 | ((c1 & 0x3) << 4)];
outptr[2] = abc[(c2 & 0x0f) << 2];
if(options.pad) {
outptr[3] = '=';
outptr += 4;
} else {
outptr += 3;
}
} else if (inlen == 1) {
int c1 = *inptr++;
outptr[0] = abc[c1 >> 2];
outptr[1] = abc[(c1 & 0x3) << 4];
if(options.pad) {
outptr[2] = '=';
outptr[3] = '=';
outptr += 4;
} else {
outptr += 2;
}
}
*outptr='\0';
return outptr - out;
}
static uchar gmime_base64_rank[256] = {
255,255,255,255,255,255,255,255,255,254,254,255,255,254,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
254,255,255,255,255,255,255,255,255,255,255, 62,255,255,255, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61,255,255,255,253,255,255,
255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,255,255,255,255,255,
255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
};
static uchar gmime_base64_rank_url_safe[256] = {
255,255,255,255,255,255,255,255,255,254,254,255,255,254,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
254,255,255,255,255,255,255,255,255,255,255,255,255, 62,255,255,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61,255,255,255,253,255,255,
255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,255,255,255,255, 63,
255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
};
size_t pa_base64_decode(const uchar *in, size_t inlen, uchar *out, Base64Options options) {
const uchar *inptr = in;
uchar *outptr = out;
const uchar *inend = in + inlen;
int saved = 0;
int state = 0;
uchar *abc_rank = options.abc == base64_alphabet ? gmime_base64_rank : gmime_base64_rank_url_safe;
/* convert 4 base64 bytes to 3 normal bytes */
while (inptr < inend) {
uchar c = abc_rank[*inptr++];
switch(c) {
case 255: // non-base64 and non-whitespace chars. not allowed in strict mode
if(options.strict)
throw Exception(BASE64_FORMAT, 0, "Invalid base64 char on position %d is detected", inptr - in - 1);
case 254: // whitespace chars 0x09, 0x0A, 0x0D, 0x20 are allowed in any mode
break;
case 253: // =
if(state < 2) {
if(options.strict)
throw Exception(BASE64_FORMAT, 0, "Unexpected '=' on position %d is detected", inptr - in - 1);
break;
}
if(state == 2) { // double '='
if(inptr == inend) {
if(options.strict)
throw Exception(BASE64_FORMAT, 0, "Unexpected end of chars");
break;
}
if(*inptr != '=') {
if(options.strict)
throw Exception(BASE64_FORMAT, 0, "Unexpected '=' on position %d is detected", inptr - in - 1);
break;
}
inptr++;
*outptr++ = (uchar)(saved >> 4);
} else { // single '='
*outptr++ = (uchar)(saved >> 10);
*outptr++ = (uchar)(saved >> 2);
}
state = 0;
break;
default:
saved = (saved << 6) | c;
state++;
if (state == 4) {
*outptr++ = (uchar)(saved >> 16);
*outptr++ = (uchar)(saved >> 8);
*outptr++ = (uchar)(saved);
state = 0;
}
}
}
if(state > 0) {
if(state > 1) {
if(options.pad && options.strict)
throw Exception(BASE64_FORMAT, 0, "Unexpected end of chars");
if(state == 2) {
*outptr++ = (uchar)(saved >> 4);
} else {
*outptr++ = (uchar)(saved >> 10);
*outptr++ = (uchar)(saved >> 2);
}
} else {
if(options.strict)
throw Exception(BASE64_FORMAT, 0, "Unexpected end of chars");
}
}
*outptr='\0'; // for text files
return outptr - out;
}
char* pa_base64_encode(const char *in, size_t in_size, Base64Options options) {
size_t new_size = ((in_size / 3 + 1) * 4);
if (options.wrap)
new_size += new_size / (BASE64_GROUPS_IN_LINE * 4) /*new lines*/;
char* result = new(PointerFreeGC) char[new_size + 1 /*zero terminator*/];
PA_UNUSED size_t filled = pa_base64_encode((const uchar*)in, in_size, (uchar*)result, options);
assert(filled <= new_size);
return result;
}
size_t pa_base64_decode(const char *in, size_t in_size, char*& result, Base64Options options) {
// every 4 base64 bytes are converted into 3 normal bytes
size_t new_size = (in_size + 3) / 4 * 3;
result = new(PointerFreeGC) char[new_size + 1 /*terminator*/];
return pa_base64_decode((const uchar*)in, in_size, (uchar*)result, options);
}
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