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