Add an unpatched version of xz, XZ Utils, to /trunk/deps/third_party

xz/src/liblzma/simple/x86.c

+///////////////////////////////////////////////////////////////////////////////
+//
+/// \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);
+}