src/liblzma/simple/arm.c

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       arm.c
   4 /// \brief      Filter for ARM binaries
   5 ///
   6 //  Authors:    Igor Pavlov
   7 //              Lasse Collin
   8 //
   9 //  This file has been put into the public domain.
  10 //  You can do whatever you want with this file.
  11 //
  12 ///////////////////////////////////////////////////////////////////////////////
  13
  14 #include "simple_private.h"
  15
  16
  17 static size_t
  18 arm_code(void *simple lzma_attribute((__unused__)),
  19                 uint32_t now_pos, bool is_encoder,
  20                 uint8_t *buffer, size_t size)
  21 {
  22         size_t i;
  23         for (i = 0; i + 4 <= size; i += 4) {
  24                 if (buffer[i + 3] == 0xEB) {
  25                         uint32_t src = (buffer[i + 2] << 16)
  26                                         | (buffer[i + 1] << 8)
  27                                         | (buffer[i + 0]);
  28                         src <<= 2;
  29
  30                         uint32_t dest;
  31                         if (is_encoder)
  32                                 dest = now_pos + (uint32_t)(i) + 8 + src;
  33                         else
  34                                 dest = src - (now_pos + (uint32_t)(i) + 8);
  35
  36                         dest >>= 2;
  37                         buffer[i + 2] = (dest >> 16);
  38                         buffer[i + 1] = (dest >> 8);
  39                         buffer[i + 0] = dest;
  40                 }
  41         }
  42
  43         return i;
  44 }
  45
  46
  47 static lzma_ret
  48 arm_coder_init(lzma_next_coder *next, const lzma_allocator *allocator,
  49                 const lzma_filter_info *filters, bool is_encoder)
  50 {
  51         return lzma_simple_coder_init(next, allocator, filters,
  52                         &arm_code, 0, 4, 4, is_encoder);
  53 }
  54
  55
  56 extern lzma_ret
  57 lzma_simple_arm_encoder_init(lzma_next_coder *next,
  58                 const lzma_allocator *allocator,
  59                 const lzma_filter_info *filters)
  60 {
  61         return arm_coder_init(next, allocator, filters, true);
  62 }
  63
  64
  65 extern lzma_ret
  66 lzma_simple_arm_decoder_init(lzma_next_coder *next,
  67                 const lzma_allocator *allocator,
  68                 const lzma_filter_info *filters)
  69 {
  70         return arm_coder_init(next, allocator, filters, false);
  71 }