Commit 99e77eff authored by Philipp Schafft's avatar Philipp Schafft 🦁
Browse files

Feature: Added base64 decoder

parent 9df4b6ea
/*
* Copyright (C) 2021 Philipp Schafft <lion@lion.leolix.org>
*
* 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 Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef __BASE64_H__
#define __BASE64_H__
#ifdef __cplusplus
extern "C" {
#endif
#include <stddef.h>
// returns 0 on success.
int base64_decode(const char *in, void **out, size_t *len);
#ifdef __cplusplus
}
#endif
#endif
......@@ -2,12 +2,14 @@
AM_CPPFLAGS = -I$(top_srcdir)/include
noinst_LIBRARIES = libutf8.a libgetopt.a
noinst_LIBRARIES = libutf8.a libgetopt.a libbase64.a
libutf8_a_SOURCES = charset.c charset.h iconvert.c utf8.c
libgetopt_a_SOURCES = getopt.c getopt1.c
libbase64_a_SOURCES = base64.c
EXTRA_DIST = charmaps.h makemap.c charset_test.c charsetmap.h
debug:
......
/*
* Copyright (C) 2002 Michael Smith <msmith@xiph.org>
* Copyright (C) 2015-2021 Philipp Schafft <lion@lion.leolix.org>
*
* 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 Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <string.h>
#include <stdlib.h>
#include "base64.h"
static const signed char base64decode[256] = {
-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, 62, -2, -2, -2, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -2, -2, -2, -1, -2, -2,
-2, 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, -2, -2, -2, -2, -2,
-2, 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, -2, -2, -2, -2, -2,
-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2
};
int base64_decode(const char *in, void **out, size_t *len)
{
const unsigned char *input = (const unsigned char *)in;
size_t todo = strlen(in);
char *output;
size_t opp = 0; // output pointer
if (todo < 4 || (todo % 4) != 0)
return -1;
output = calloc(1, todo*3/4 + 5);
if (!output)
return -1;
while (todo) {
signed char vals[4];
size_t i;
for (i = 0; i < (sizeof(vals)/sizeof(*vals)); i++)
vals[i] = base64decode[*input++];
if(vals[0] < 0 || vals[1] < 0 || vals[2] < -1 || vals[3] < -1) {
todo -= 4;
continue;
}
output[opp++] = vals[0]<<2 | vals[1]>>4;
/* vals[3] and (if that is) vals[2] can be '=' as padding, which is
* looked up in the base64decode table as '-1'. Check for this case,
* and output zero-terminators instead of characters if we've got
* padding. */
if (vals[2] >= 0) {
output[opp++] = ((vals[1]&0x0F)<<4) | (vals[2]>>2);
} else {
break;
}
if (vals[3] >= 0) {
output[opp++] = ((vals[2]&0x03)<<6) | (vals[3]);
} else {
break;
}
todo -= 4;
}
output[opp++] = 0;
*out = output;
*len = opp - 1;
return 0;
}
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