56 lines
1.1 KiB
C
56 lines
1.1 KiB
C
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/* $OpenBSD: c_rle.c,v 1.8 2014/11/03 16:58:28 tedu Exp $ */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <openssl/objects.h>
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#include <openssl/comp.h>
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static int rle_compress_block(COMP_CTX *ctx, unsigned char *out,
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unsigned int olen, unsigned char *in, unsigned int ilen);
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static int rle_expand_block(COMP_CTX *ctx, unsigned char *out,
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unsigned int olen, unsigned char *in, unsigned int ilen);
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static COMP_METHOD rle_method = {
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.type = NID_rle_compression,
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.name = LN_rle_compression,
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.compress = rle_compress_block,
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.expand = rle_expand_block
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};
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COMP_METHOD *
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COMP_rle(void)
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{
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return (&rle_method);
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}
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static int
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rle_compress_block(COMP_CTX *ctx, unsigned char *out, unsigned int olen,
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unsigned char *in, unsigned int ilen)
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{
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if (ilen == 0 || olen < (ilen - 1)) {
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return (-1);
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}
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*(out++) = 0;
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memcpy(out, in, ilen);
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return (ilen + 1);
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}
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static int
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rle_expand_block(COMP_CTX *ctx, unsigned char *out, unsigned int olen,
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unsigned char *in, unsigned int ilen)
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{
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int i;
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if (olen < (ilen - 1)) {
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return (-1);
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}
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i= *(in++);
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if (i == 0) {
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memcpy(out, in, ilen - 1);
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}
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return (ilen - 1);
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}
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