crypto/comp/c_rle.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <openssl/objects.h>
   5 #include <openssl/comp.h>
   6
   7 static int rle_compress_block(COMP_CTX *ctx, unsigned char *out,
   8                               unsigned int olen, unsigned char *in,
   9                               unsigned int ilen);
  10 static int rle_expand_block(COMP_CTX *ctx, unsigned char *out,
  11                             unsigned int olen, unsigned char *in,
  12                             unsigned int ilen);
  13
  14 static 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
  25 COMP_METHOD *COMP_rle(void)
  26 {
  27     return (&rle_method);
  28 }
  29
  30 static 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
  45 static 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 }