c_rle.c revision 325335 
1#include <stdio.h>
2#include <stdlib.h>
3#include <string.h>
4#include <openssl/objects.h>
5#include <openssl/comp.h>
6
7static int rle_compress_block(COMP_CTX *ctx, unsigned char *out,
8                              unsigned int olen, unsigned char *in,
9                              unsigned int ilen);
10static int rle_expand_block(COMP_CTX *ctx, unsigned char *out,
11                            unsigned int olen, unsigned char *in,
12                            unsigned int ilen);
13
14static COMP_METHOD rle_method = {
15    NID_rle_compression,
16    LN_rle_compression,
17    NULL,
18    NULL,
19    rle_compress_block,
20    rle_expand_block,
21    NULL,
22    NULL,
23};
24
25COMP_METHOD *COMP_rle(void)
26{
27    return (&rle_method);
28}
29
30static int rle_compress_block(COMP_CTX *ctx, unsigned char *out,
31                              unsigned int olen, unsigned char *in,
32                              unsigned int ilen)
33{
34    if (ilen == 0)
35        return 0;
36
37    if (olen <= ilen)
38        return -1;
39
40    *(out++) = 0;
41    memcpy(out, in, ilen);
42    return (ilen + 1);
43}
44
45static int rle_expand_block(COMP_CTX *ctx, unsigned char *out,
46                            unsigned int olen, unsigned char *in,
47                            unsigned int ilen)
48{
49    int i;
50
51    if (ilen == 0)
52        return 0;
53
54    if (olen < (ilen - 1))
55        return -1;
56
57    i = *(in++);
58    if (i != 0)
59        return -1;
60
61    memcpy(out, in, ilen - 1);
62    return (ilen - 1);
63}
64