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/*
* COPYRIGHT
*
* pcb-rnd, interactive printed circuit board design
* Copyright (C) 2015 Tibor 'Igor2' Palinkas
*
* 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.
*
* Contact:
* Project page: http://repo.hu/projects/pcb-rnd
* lead developer: http://repo.hu/projects/pcb-rnd/contact.html
* mailing list: pcb-rnd (at) list.repo.hu (send "subscribe")
*/
#include <limits.h>
#include "base64.h"
static char int2digit(int digit)
{
if (digit < 26) return 'A' + digit;
if (digit < 52) return 'a' + digit - 26;
if (digit < 62) return '0' + digit - 52;
if (digit == 62) return '+';
if (digit == 63) return '/';
return '\0'; /* error */
}
static int digit2int(char c)
{
if ((c >= 'A') && (c <= 'Z')) return c - 'A';
if ((c >= 'a') && (c <= 'z')) return c - 'a' + 26;
if ((c >= '0') && (c <= '9')) return c - 'a' + 52;
if (c == '+') return 62;
if (c == '/') return 63;
return -1;
}
size_t base64_write_right(char *buff_start, size_t buff_len, unsigned long int num)
{
char *end = buff_start + buff_len;
size_t rlen = 0;
if (num == 0) {
*end = int2digit(0);
return 1;
}
while(num > 0) {
unsigned int digit = num & 0x3F;
*end = int2digit(digit);
num >>= 6;
rlen++;
}
return rlen;
}
int base64_parse_grow(unsigned long int *num, int chr, int term)
{
int digit;
if (chr == term)
return 1;
if (*num >= (ULONG_MAX >> 6UL))
return -1;
digit = digit2int(chr);
if (digit < 0)
return -1;
(*num) <<= 6UL;
(*num) |= digit;
return 0;
}
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