target/linux/ar71xx/patches-4.4/310-lib-add-rle-decompression.patch

   1 --- a/lib/Kconfig
   2 +++ b/lib/Kconfig
   3 @@ -247,6 +247,9 @@ 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 @@ -110,6 +110,7 @@ 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 +1,18 @@
  26 +#ifndef _RLE_H_
  27 +#define _RLE_H_
  28 +
  29 +#ifdef CONFIG_RLE_DECOMPRESS
  30 +int rle_decode(const unsigned char *src, size_t srclen,
  31 +              unsigned char *dst, size_t dstlen,
  32 +              size_t *src_done, size_t *dst_done);
  33 +#else
  34 +static inline int
  35 +rle_decode(const unsigned char *src, size_t srclen,
  36 +          unsigned char *dst, size_t dstlen,
  37 +          size_t *src_done, size_t *dst_done)
  38 +{
  39 +       return -ENOTSUPP;
  40 +}
  41 +#endif /* CONFIG_RLE_DECOMPRESS */
  42 +
  43 +#endif /* _RLE_H_ */
  44 --- /dev/null
  45 +++ b/lib/rle.c
  46 @@ -0,0 +1,78 @@
  47 +/*
  48 + *  RLE decoding routine
  49 + *
  50 + *  Copyright (C) 2012 Gabor Juhos <juhosg@openwrt.org>
  51 + *
  52 + *  This program is free software; you can redistribute it and/or modify it
  53 + *  under the terms of the GNU General Public License version 2 as published
  54 + *  by the Free Software Foundation.
  55 + */
  56 +
  57 +#include <linux/kernel.h>
  58 +#include <linux/module.h>
  59 +#include <linux/rle.h>
  60 +
  61 +int rle_decode(const unsigned char *src, size_t srclen,
  62 +              unsigned char *dst, size_t dstlen,
  63 +              size_t *src_done, size_t *dst_done)
  64 +{
  65 +       size_t srcpos, dstpos;
  66 +       int ret;
  67 +
  68 +       srcpos = 0;
  69 +       dstpos = 0;
  70 +       ret = -EINVAL;
  71 +
  72 +       /* sanity checks */
  73 +       if (!src || !srclen || !dst || !dstlen)
  74 +               goto out;
  75 +
  76 +       while (1) {
  77 +               char count;
  78 +
  79 +               if (srcpos >= srclen)
  80 +                       break;
  81 +
  82 +               count = (char) src[srcpos++];
  83 +               if (count == 0) {
  84 +                       ret = 0;
  85 +                       break;
  86 +               }
  87 +
  88 +               if (count > 0) {
  89 +                       unsigned char c;
  90 +
  91 +                       if (srcpos >= srclen)
  92 +                               break;
  93 +
  94 +                       c = src[srcpos++];
  95 +
  96 +                       while (count--) {
  97 +                               if (dstpos >= dstlen)
  98 +                                       break;
  99 +
 100 +                               dst[dstpos++] = c;
 101 +                       }
 102 +               } else {
 103 +                       count *= -1;
 104 +
 105 +                       while (count--) {
 106 +                               if (srcpos >= srclen)
 107 +                                       break;
 108 +                               if (dstpos >= dstlen)
 109 +                                       break;
 110 +                               dst[dstpos++] = src[srcpos++];
 111 +                       }
 112 +               }
 113 +       }
 114 +
 115 +out:
 116 +       if (src_done)
 117 +               *src_done = srcpos;
 118 +       if (dst_done)
 119 +               *dst_done = dstpos;
 120 +
 121 +       return ret;
 122 +}
 123 +
 124 +EXPORT_SYMBOL_GPL(rle_decode);