target/linux/ar71xx/patches-3.10/310-lib-add-rle-decompression.patch

   1 --- a/lib/Kconfig
   2 +++ b/lib/Kconfig
   3 @@ -197,6 +197,9 @@ config LZMA_COMPRESS
   4  config LZMA_DECOMPRESS
   5      tristate
   6
   7 +config RLE_DECOMPRESS
   8 +       tristate
   9 +
  10  #
  11  # These all provide a common interface (hence the apparent duplication with
  12  # ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
  13 --- a/lib/Makefile
  14 +++ b/lib/Makefile
  15 @@ -89,6 +89,7 @@ obj-$(CONFIG_XZ_DEC) += xz/
  16  obj-$(CONFIG_RAID6_PQ) += raid6/
  17  obj-$(CONFIG_LZMA_COMPRESS) += lzma/
  18  obj-$(CONFIG_LZMA_DECOMPRESS) += lzma/
  19 +obj-$(CONFIG_RLE_DECOMPRESS) += rle.o
  20
  21  lib-$(CONFIG_DECOMPRESS_GZIP) += decompress_inflate.o
  22  lib-$(CONFIG_DECOMPRESS_BZIP2) += decompress_bunzip2.o
  23 --- /dev/null
  24 +++ b/include/linux/rle.h
  25 @@ -0,0 +1,8 @@
  26 +#ifndef _RLE_H_
  27 +#define _RLE_H_
  28 +
  29 +int rle_decode(const unsigned char *src, size_t srclen,
  30 +              unsigned char *dst, size_t dstlen,
  31 +              size_t *src_done, size_t *dst_done);
  32 +
  33 +#endif /* _RLE_H_ */
  34 --- /dev/null
  35 +++ b/lib/rle.c
  36 @@ -0,0 +1,78 @@
  37 +/*
  38 + *  RLE decoding routine
  39 + *
  40 + *  Copyright (C) 2012 Gabor Juhos <juhosg@openwrt.org>
  41 + *
  42 + *  This program is free software; you can redistribute it and/or modify it
  43 + *  under the terms of the GNU General Public License version 2 as published
  44 + *  by the Free Software Foundation.
  45 + */
  46 +
  47 +#include <linux/kernel.h>
  48 +#include <linux/module.h>
  49 +#include <linux/rle.h>
  50 +
  51 +int rle_decode(const unsigned char *src, size_t srclen,
  52 +              unsigned char *dst, size_t dstlen,
  53 +              size_t *src_done, size_t *dst_done)
  54 +{
  55 +       size_t srcpos, dstpos;
  56 +       int ret;
  57 +
  58 +       srcpos = 0;
  59 +       dstpos = 0;
  60 +       ret = -EINVAL;
  61 +
  62 +       /* sanity checks */
  63 +       if (!src || !srclen || !dst || !dstlen)
  64 +               goto out;
  65 +
  66 +       while (1) {
  67 +               char count;
  68 +
  69 +               if (srcpos >= srclen)
  70 +                       break;
  71 +
  72 +               count = (char) src[srcpos++];
  73 +               if (count == 0) {
  74 +                       ret = 0;
  75 +                       break;
  76 +               }
  77 +
  78 +               if (count > 0) {
  79 +                       unsigned char c;
  80 +
  81 +                       if (srcpos >= srclen)
  82 +                               break;
  83 +
  84 +                       c = src[srcpos++];
  85 +
  86 +                       while (count--) {
  87 +                               if (dstpos >= dstlen)
  88 +                                       break;
  89 +
  90 +                               dst[dstpos++] = c;
  91 +                       }
  92 +               } else {
  93 +                       count *= -1;
  94 +
  95 +                       while (count--) {
  96 +                               if (srcpos >= srclen)
  97 +                                       break;
  98 +                               if (dstpos >= dstlen)
  99 +                                       break;
 100 +                               dst[dstpos++] = src[srcpos++];
 101 +                       }
 102 +               }
 103 +       }
 104 +
 105 +out:
 106 +       if (src_done)
 107 +               *src_done = srcpos;
 108 +       if (dst_done)
 109 +               *dst_done = dstpos;
 110 +
 111 +       return ret;
 112 +}
 113 +
 114 +EXPORT_SYMBOL_GPL(rle_decode);