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/* $OpenBSD: c_rle.c,v 1.9 2022/01/09 23:50:10 tb Exp $ */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/objects.h>
#include <openssl/comp.h>
#include "comp_local.h"
static int rle_compress_block(COMP_CTX *ctx, unsigned char *out,
unsigned int olen, unsigned char *in, unsigned int ilen);
static int rle_expand_block(COMP_CTX *ctx, unsigned char *out,
unsigned int olen, unsigned char *in, unsigned int ilen);
static COMP_METHOD rle_method = {
.type = NID_rle_compression,
.name = LN_rle_compression,
.compress = rle_compress_block,
.expand = rle_expand_block
};
COMP_METHOD *
COMP_rle(void)
{
return (&rle_method);
}
static int
rle_compress_block(COMP_CTX *ctx, unsigned char *out, unsigned int olen,
unsigned char *in, unsigned int ilen)
{
if (ilen == 0 || olen < (ilen - 1)) {
return (-1);
}
*(out++) = 0;
memcpy(out, in, ilen);
return (ilen + 1);
}
static int
rle_expand_block(COMP_CTX *ctx, unsigned char *out, unsigned int olen,
unsigned char *in, unsigned int ilen)
{
int i;
if (olen < (ilen - 1)) {
return (-1);
}
i= *(in++);
if (i == 0) {
memcpy(out, in, ilen - 1);
}
return (ilen - 1);
}
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