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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 21:12:04 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 21:12:04 +0000 |
commit | eac54b7c4aec25060d7bd856f7cdc290943d6aae (patch) | |
tree | 9a6d81c9f88df4698e746d63d14ddafeddd918b8 /src/liblzma/simple/x86.c | |
parent | Initial commit. (diff) | |
download | xz-utils-eac54b7c4aec25060d7bd856f7cdc290943d6aae.tar.xz xz-utils-eac54b7c4aec25060d7bd856f7cdc290943d6aae.zip |
Adding upstream version 5.4.1.upstream/5.4.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/liblzma/simple/x86.c')
-rw-r--r-- | src/liblzma/simple/x86.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/src/liblzma/simple/x86.c b/src/liblzma/simple/x86.c new file mode 100644 index 0000000..232b295 --- /dev/null +++ b/src/liblzma/simple/x86.c @@ -0,0 +1,163 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \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) + + +typedef struct { + uint32_t prev_mask; + uint32_t prev_pos; +} lzma_simple_x86; + + +static size_t +x86_code(void *simple_ptr, 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 }; + + lzma_simple_x86 *simple = simple_ptr; + 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 ^ ((1U << (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, const 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_x86), 5, 1, is_encoder); + + if (ret == LZMA_OK) { + lzma_simple_coder *coder = next->coder; + lzma_simple_x86 *simple = coder->simple; + simple->prev_mask = 0; + simple->prev_pos = (uint32_t)(-5); + } + + return ret; +} + + +#ifdef HAVE_ENCODER_X86 +extern lzma_ret +lzma_simple_x86_encoder_init(lzma_next_coder *next, + const lzma_allocator *allocator, + const lzma_filter_info *filters) +{ + return x86_coder_init(next, allocator, filters, true); +} +#endif + + +#ifdef HAVE_DECODER_X86 +extern lzma_ret +lzma_simple_x86_decoder_init(lzma_next_coder *next, + const lzma_allocator *allocator, + const lzma_filter_info *filters) +{ + return x86_coder_init(next, allocator, filters, false); +} +#endif |