crypto/libressl/crypto/comp/c_rle.c

   1 /* $OpenBSD: c_rle.c,v 1.7 2014/06/12 15:49:28 deraadt Exp $ */
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include <openssl/objects.h>
   6 #include <openssl/comp.h>
   7
   8 static int rle_compress_block(COMP_CTX *ctx, unsigned char *out,
   9     unsigned int olen, unsigned char *in, unsigned int ilen);
  10 static int rle_expand_block(COMP_CTX *ctx, unsigned char *out,
  11     unsigned int olen, unsigned char *in, unsigned int ilen);
  12
  13 static COMP_METHOD rle_method = {
  14         .type = NID_rle_compression,
  15         .name = LN_rle_compression,
  16         .compress = rle_compress_block,
  17         .expand = rle_expand_block
  18 };
  19
  20 COMP_METHOD *
  21 COMP_rle(void)
  22 {
  23         return (&rle_method);
  24 }
  25
  26 static int
  27 rle_compress_block(COMP_CTX *ctx, unsigned char *out, unsigned int olen,
  28     unsigned char *in, unsigned int ilen)
  29 {
  30
  31         if (ilen == 0 || olen < (ilen - 1)) {
  32                 return (-1);
  33         }
  34
  35         *(out++) = 0;
  36         memcpy(out, in, ilen);
  37         return (ilen + 1);
  38 }
  39
  40 static int
  41 rle_expand_block(COMP_CTX *ctx, unsigned char *out, unsigned int olen,
  42     unsigned char *in, unsigned int ilen)
  43 {
  44         int i;
  45
  46         if (olen < (ilen - 1)) {
  47                 return (-1);
  48         }
  49
  50         i= *(in++);
  51         if (i == 0) {
  52                 memcpy(out, in, ilen - 1);
  53         }
  54         return (ilen - 1);
  55 }