1 ///////////////////////////////////////////////////////////////////////////////
4 /// \brief Filter for x86 binaries (BCJ filter)
6 // Authors: Igor Pavlov
9 // This file has been put into the public domain.
10 // You can do whatever you want with this file.
12 ///////////////////////////////////////////////////////////////////////////////
14 #include "simple_private.h"
17 #define Test86MSByte(b) ((b) == 0 || (b) == 0xFF)
20 struct lzma_simple_s {
27 x86_code(lzma_simple *simple, uint32_t now_pos, bool is_encoder,
28 uint8_t *buffer, size_t size)
30 static const bool MASK_TO_ALLOWED_STATUS[8]
31 = { true, true, true, false, true, false, false, false };
33 static const uint32_t MASK_TO_BIT_NUMBER[8]
34 = { 0, 1, 2, 2, 3, 3, 3, 3 };
36 uint32_t prev_mask = simple->prev_mask;
37 uint32_t prev_pos = simple->prev_pos;
42 if (now_pos - prev_pos > 5)
43 prev_pos = now_pos - 5;
45 const size_t limit = size - 5;
46 size_t buffer_pos = 0;
48 while (buffer_pos <= limit) {
49 uint8_t b = buffer[buffer_pos];
50 if (b != 0xE8 && b != 0xE9) {
55 const uint32_t offset = now_pos + (uint32_t)(buffer_pos)
57 prev_pos = now_pos + (uint32_t)(buffer_pos);
63 for (i = 0; i < offset; ++i) {
69 b = buffer[buffer_pos + 4];
72 && MASK_TO_ALLOWED_STATUS[(prev_mask >> 1) & 0x7]
73 && (prev_mask >> 1) < 0x10) {
75 uint32_t src = ((uint32_t)(b) << 24)
76 | ((uint32_t)(buffer[buffer_pos + 3]) << 16)
77 | ((uint32_t)(buffer[buffer_pos + 2]) << 8)
78 | (buffer[buffer_pos + 1]);
83 dest = src + (now_pos + (uint32_t)(
86 dest = src - (now_pos + (uint32_t)(
92 const uint32_t i = MASK_TO_BIT_NUMBER[
95 b = (uint8_t)(dest >> (24 - i * 8));
100 src = dest ^ ((1 << (32 - i * 8)) - 1);
103 buffer[buffer_pos + 4]
104 = (uint8_t)(~(((dest >> 24) & 1) - 1));
105 buffer[buffer_pos + 3] = (uint8_t)(dest >> 16);
106 buffer[buffer_pos + 2] = (uint8_t)(dest >> 8);
107 buffer[buffer_pos + 1] = (uint8_t)(dest);
119 simple->prev_mask = prev_mask;
120 simple->prev_pos = prev_pos;
127 x86_coder_init(lzma_next_coder *next, lzma_allocator *allocator,
128 const lzma_filter_info *filters, bool is_encoder)
130 const lzma_ret ret = lzma_simple_coder_init(next, allocator, filters,
131 &x86_code, sizeof(lzma_simple), 5, 1, is_encoder);
133 if (ret == LZMA_OK) {
134 next->coder->simple->prev_mask = 0;
135 next->coder->simple->prev_pos = (uint32_t)(-5);
143 lzma_simple_x86_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
144 const lzma_filter_info *filters)
146 return x86_coder_init(next, allocator, filters, true);
151 lzma_simple_x86_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
152 const lzma_filter_info *filters)
154 return x86_coder_init(next, allocator, filters, false);