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/*
* RLE decoding routine
*
* Copyright (C) 2012 Gabor Juhos <juhosg@openwrt.org>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*/
#include <stdio.h>
#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#include <sys/types.h>
#include "rle.h"
int rle_decode(const unsigned char *src, size_t srclen,
unsigned char *dst, size_t dstlen,
size_t *src_done, size_t *dst_done)
{
size_t srcpos, dstpos;
int ret;
srcpos = 0;
dstpos = 0;
ret = 1;
/* sanity checks */
if (!src || !srclen || !dst || !dstlen)
goto out;
while (1) {
signed char count;
if (srcpos >= srclen)
break;
count = (signed char) src[srcpos++];
if (count == 0) {
ret = 0;
break;
}
if (count > 0) {
unsigned char c;
if (srcpos >= srclen)
break;
c = src[srcpos++];
while (count--) {
if (dstpos >= dstlen)
break;
dst[dstpos++] = c;
}
} else {
count *= -1;
while (count--) {
if (srcpos >= srclen)
break;
if (dstpos >= dstlen)
break;
dst[dstpos++] = src[srcpos++];
}
}
}
out:
if (src_done)
*src_done = srcpos;
if (dst_done)
*dst_done = dstpos;
return ret;
}
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