Index: xz/src/liblzma/simple/x86.c |
=================================================================== |
--- xz/src/liblzma/simple/x86.c (revision 0) |
+++ xz/src/liblzma/simple/x86.c (revision 0) |
@@ -0,0 +1,154 @@ |
+/////////////////////////////////////////////////////////////////////////////// |
+// |
+/// \file x86.c |
+/// \brief Filter for x86 binaries (BCJ filter) |
+/// |
+// Authors: Igor Pavlov |
+// Lasse Collin |
+// |
+// This file has been put into the public domain. |
+// You can do whatever you want with this file. |
+// |
+/////////////////////////////////////////////////////////////////////////////// |
+ |
+#include "simple_private.h" |
+ |
+ |
+#define Test86MSByte(b) ((b) == 0 || (b) == 0xFF) |
+ |
+ |
+struct lzma_simple_s { |
+ uint32_t prev_mask; |
+ uint32_t prev_pos; |
+}; |
+ |
+ |
+static size_t |
+x86_code(lzma_simple *simple, uint32_t now_pos, bool is_encoder, |
+ uint8_t *buffer, size_t size) |
+{ |
+ static const bool MASK_TO_ALLOWED_STATUS[8] |
+ = { true, true, true, false, true, false, false, false }; |
+ |
+ static const uint32_t MASK_TO_BIT_NUMBER[8] |
+ = { 0, 1, 2, 2, 3, 3, 3, 3 }; |
+ |
+ uint32_t prev_mask = simple->prev_mask; |
+ uint32_t prev_pos = simple->prev_pos; |
+ |
+ if (size < 5) |
+ return 0; |
+ |
+ if (now_pos - prev_pos > 5) |
+ prev_pos = now_pos - 5; |
+ |
+ const size_t limit = size - 5; |
+ size_t buffer_pos = 0; |
+ |
+ while (buffer_pos <= limit) { |
+ uint8_t b = buffer[buffer_pos]; |
+ if (b != 0xE8 && b != 0xE9) { |
+ ++buffer_pos; |
+ continue; |
+ } |
+ |
+ const uint32_t offset = now_pos + (uint32_t)(buffer_pos) |
+ - prev_pos; |
+ prev_pos = now_pos + (uint32_t)(buffer_pos); |
+ |
+ if (offset > 5) { |
+ prev_mask = 0; |
+ } else { |
+ for (uint32_t i = 0; i < offset; ++i) { |
+ prev_mask &= 0x77; |
+ prev_mask <<= 1; |
+ } |
+ } |
+ |
+ b = buffer[buffer_pos + 4]; |
+ |
+ if (Test86MSByte(b) |
+ && MASK_TO_ALLOWED_STATUS[(prev_mask >> 1) & 0x7] |
+ && (prev_mask >> 1) < 0x10) { |
+ |
+ uint32_t src = ((uint32_t)(b) << 24) |
+ | ((uint32_t)(buffer[buffer_pos + 3]) << 16) |
+ | ((uint32_t)(buffer[buffer_pos + 2]) << 8) |
+ | (buffer[buffer_pos + 1]); |
+ |
+ uint32_t dest; |
+ while (true) { |
+ if (is_encoder) |
+ dest = src + (now_pos + (uint32_t)( |
+ buffer_pos) + 5); |
+ else |
+ dest = src - (now_pos + (uint32_t)( |
+ buffer_pos) + 5); |
+ |
+ if (prev_mask == 0) |
+ break; |
+ |
+ const uint32_t i = MASK_TO_BIT_NUMBER[ |
+ prev_mask >> 1]; |
+ |
+ b = (uint8_t)(dest >> (24 - i * 8)); |
+ |
+ if (!Test86MSByte(b)) |
+ break; |
+ |
+ src = dest ^ ((1 << (32 - i * 8)) - 1); |
+ } |
+ |
+ buffer[buffer_pos + 4] |
+ = (uint8_t)(~(((dest >> 24) & 1) - 1)); |
+ buffer[buffer_pos + 3] = (uint8_t)(dest >> 16); |
+ buffer[buffer_pos + 2] = (uint8_t)(dest >> 8); |
+ buffer[buffer_pos + 1] = (uint8_t)(dest); |
+ buffer_pos += 5; |
+ prev_mask = 0; |
+ |
+ } else { |
+ ++buffer_pos; |
+ prev_mask |= 1; |
+ if (Test86MSByte(b)) |
+ prev_mask |= 0x10; |
+ } |
+ } |
+ |
+ simple->prev_mask = prev_mask; |
+ simple->prev_pos = prev_pos; |
+ |
+ return buffer_pos; |
+} |
+ |
+ |
+static lzma_ret |
+x86_coder_init(lzma_next_coder *next, lzma_allocator *allocator, |
+ const lzma_filter_info *filters, bool is_encoder) |
+{ |
+ const lzma_ret ret = lzma_simple_coder_init(next, allocator, filters, |
+ &x86_code, sizeof(lzma_simple), 5, 1, is_encoder); |
+ |
+ if (ret == LZMA_OK) { |
+ next->coder->simple->prev_mask = 0; |
+ next->coder->simple->prev_pos = (uint32_t)(-5); |
+ } |
+ |
+ return ret; |
+} |
+ |
+ |
+extern lzma_ret |
+lzma_simple_x86_encoder_init(lzma_next_coder *next, lzma_allocator *allocator, |
+ const lzma_filter_info *filters) |
+{ |
+ return x86_coder_init(next, allocator, filters, true); |
+} |
+ |
+ |
+extern lzma_ret |
+lzma_simple_x86_decoder_init(lzma_next_coder *next, lzma_allocator *allocator, |
+ const lzma_filter_info *filters) |
+{ |
+ return x86_coder_init(next, allocator, filters, false); |
+} |
Property changes on: xz/src/liblzma/simple/x86.c |
___________________________________________________________________ |
Added: svn:eol-style |
+ LF |