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/*
* base64.c
* base64 encode/decode implementation
*
* Copyright (c) 2011 Nikias Bassen, All Rights Reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <string.h>
#include "base64.h"
static const char base64_str[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const char base64_pad = '=';
static const signed char base64_table[256] = {
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
-1, 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, -1, -1, -1, -1, -1,
-1, 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, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
};
size_t base64encode(char *outbuf, const unsigned char *buf, size_t size)
{
if (!outbuf || !buf || (size <= 0)) {
return 0;
}
size_t n = 0;
size_t m = 0;
unsigned char input[3];
unsigned int output[4];
while (n < size) {
input[0] = buf[n];
input[1] = (n+1 < size) ? buf[n+1] : 0;
input[2] = (n+2 < size) ? buf[n+2] : 0;
output[0] = input[0] >> 2;
output[1] = ((input[0] & 3) << 4) + (input[1] >> 4);
output[2] = ((input[1] & 15) << 2) + (input[2] >> 6);
output[3] = input[2] & 63;
outbuf[m++] = base64_str[(int)output[0]];
outbuf[m++] = base64_str[(int)output[1]];
outbuf[m++] = (n+1 < size) ? base64_str[(int)output[2]] : base64_pad;
outbuf[m++] = (n+2 < size) ? base64_str[(int)output[3]] : base64_pad;
n+=3;
}
outbuf[m] = 0; // 0-termination!
return m;
}
static int base64decode_block(unsigned char *target, const char *data, size_t data_size)
{
int w1,w2,w3,w4;
int i;
size_t n;
if (!data || (data_size <= 0)) {
return 0;
}
n = 0;
i = 0;
while (n < data_size-3) {
w1 = base64_table[(int)data[n]];
w2 = base64_table[(int)data[n+1]];
w3 = base64_table[(int)data[n+2]];
w4 = base64_table[(int)data[n+3]];
if (w2 >= 0) {
target[i++] = (char)((w1*4 + (w2 >> 4)) & 255);
}
if (w3 >= 0) {
target[i++] = (char)((w2*16 + (w3 >> 2)) & 255);
}
if (w4 >= 0) {
target[i++] = (char)((w3*64 + w4) & 255);
}
n+=4;
}
return i;
}
unsigned char *base64decode(const char *buf, size_t *size)
{
if (!buf || !size) return NULL;
size_t len = (*size > 0) ? *size : strlen(buf);
if (len <= 0) return NULL;
unsigned char *outbuf = (unsigned char*)malloc((len/4)*3+3);
const char *ptr = buf;
int p = 0;
size_t l = 0;
do {
ptr += strspn(ptr, "\r\n\t ");
if (*ptr == '\0' || ptr >= buf+len) {
break;
}
l = strcspn(ptr, "\r\n\t ");
if (l > 3 && ptr+l <= buf+len) {
p+=base64decode_block(outbuf+p, ptr, l);
ptr += l;
} else {
break;
}
} while (1);
outbuf[p] = 0;
*size = p;
return outbuf;
}
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