64 lines
1.4 KiB
C
64 lines
1.4 KiB
C
#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,
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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,
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unsigned int ilen);
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static COMP_METHOD rle_method = {
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NID_rle_compression,
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LN_rle_compression,
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NULL,
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NULL,
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rle_compress_block,
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rle_expand_block,
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NULL,
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NULL,
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};
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COMP_METHOD *COMP_rle(void)
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{
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return (&rle_method);
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}
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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,
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unsigned int ilen)
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{
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if (ilen == 0)
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return 0;
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if (olen <= ilen)
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return -1;
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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 rle_expand_block(COMP_CTX *ctx, unsigned char *out,
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unsigned int olen, unsigned char *in,
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unsigned int ilen)
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{
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int i;
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if (ilen == 0)
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return 0;
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if (olen < (ilen - 1))
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return -1;
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i = *(in++);
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if (i != 0)
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return -1;
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memcpy(out, in, ilen - 1);
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return (ilen - 1);
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}
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