*/
/*
- * Copyright (C) 2012, 2013 Eric Biggers
+ * Copyright (C) 2012, 2013, 2014 Eric Biggers
*
* This file is part of wimlib, a library for working with WIM files.
*
*/
/*
- * LZX is a LZ77 and Huffman-code based compression format that has many
+ * LZX is an LZ77 and Huffman-code based compression format that has many
* similarities to the DEFLATE format used in zlib. The compression ratio is as
* good or better than DEFLATE.
*
* last decompress to a fixed number of bytes, by default 32768. This is quite
* similar to the cabinet (.cab) file format, but they are not the same.
* According to the cabinet format documentation, the LZX block size is
- * independent from the CFDATA blocks, and a LZX block may span several CFDATA
+ * independent from the CFDATA blocks, and an LZX block may span several CFDATA
* blocks. However, in WIMs, LZX blocks do not appear to ever span multiple WIM
* chunks. Note that this means any WIM chunk may be decompressed or compressed
* independently from any other chunk, which allows random access.
*
- * A LZX compressed WIM chunk contains one or more LZX blocks of the aligned,
+ * An LZX compressed WIM chunk contains one or more LZX blocks of the aligned,
* verbatim, or uncompressed block types. For aligned and verbatim blocks, the
* size of the block in uncompressed bytes is specified by a bit following the 3
* bits that specify the block type, possibly followed by an additional 16 bits.
#endif
#include "wimlib.h"
-#include "wimlib/decompress.h"
+#include "wimlib/decompressor_ops.h"
+#include "wimlib/decompress_common.h"
#include "wimlib/lzx.h"
#include "wimlib/util.h"
#include <string.h>
+#ifdef __SSE2__
+# include <emmintrin.h>
+#endif
+
/* Huffman decoding tables and maps from symbols to code lengths. */
struct lzx_tables {
u8 alignedtree_lens[LZX_ALIGNEDCODE_NUM_SYMBOLS];
} _aligned_attribute(DECODE_TABLE_ALIGNMENT);
+struct lzx_decompressor {
+ u32 max_window_size;
+ unsigned num_main_syms;
+ struct lzx_tables tables;
+};
/*
* Reads a Huffman-encoded symbol using the pre-tree.
* code length values from the input.
*
* @istream: The bit stream for the input. It is positioned on the beginning
- * of the pretree for the code length values.
+ * of the pretree for the code length values.
* @lens: An array that contains the length values from the previous time
- * the code lengths for this Huffman tree were read, or all
- * 0's if this is the first time.
+ * the code lengths for this Huffman tree were read, or all
+ * 0's if this is the first time.
* @num_lens: Number of length values to decode and return.
*
*/
*
* @istream: The input bitstream.
* @block_size_ret: A pointer to an int into which the size of the block,
- * in bytes, will be returned.
+ * in bytes, will be returned.
* @block_type_ret: A pointer to an int into which the type of the block
- * (LZX_BLOCKTYPE_*) will be returned.
- * @tables: A pointer to a lzx_tables structure in which the
- * main tree, the length tree, and possibly the
- * aligned offset tree will be constructed.
+ * (LZX_BLOCKTYPE_*) will be returned.
+ * @tables: A pointer to an lzx_tables structure in which the
+ * main tree, the length tree, and possibly the
+ * aligned offset tree will be constructed.
* @queue: A pointer to the least-recently-used queue into which
- * R0, R1, and R2 will be written (only for uncompressed
- * blocks, which contain this information in the header)
+ * R0, R1, and R2 will be written (only for uncompressed
+ * blocks, which contain this information in the header)
*/
static int
lzx_read_block_header(struct input_bitstream *istream,
* tree.
*
* @block_type: The type of the block (LZX_BLOCKTYPE_ALIGNED or
- * LZX_BLOCKTYPE_VERBATIM)
+ * LZX_BLOCKTYPE_VERBATIM)
*
* @bytes_remaining: The amount of uncompressed data remaining to be
- * uncompressed in this block. It is an error if the match
- * is longer than this number.
+ * uncompressed in this block. It is an error if the match
+ * is longer than this number.
*
* @window: A pointer to the window into which the uncompressed
- * data is being written.
+ * data is being written.
*
* @window_pos: The current byte offset in the window.
*
*
* Returns the length of the match, or a negative number on error. The possible
* error cases are:
- * - Match would exceed the amount of data remaining to be uncompressed.
- * - Match refers to data before the window.
- * - The input bitstream ended unexpectedly.
+ * - Match would exceed the amount of data remaining to be uncompressed.
+ * - Match refers to data before the window.
+ * - The input bitstream ended unexpectedly.
*/
static int
lzx_decode_match(unsigned main_element, int block_type,
}
static void
-undo_call_insn_translation(u32 *call_insn_target, int input_pos,
- s32 file_size)
+undo_call_insn_translation(u32 *call_insn_target, s32 input_pos)
{
s32 abs_offset;
s32 rel_offset;
abs_offset = le32_to_cpu(*call_insn_target);
- if (abs_offset >= -input_pos && abs_offset < file_size) {
+ if (abs_offset >= -input_pos && abs_offset < LZX_WIM_MAGIC_FILESIZE) {
if (abs_offset >= 0) {
/* "good translation" */
rel_offset = abs_offset - input_pos;
} else {
/* "compensating translation" */
- rel_offset = abs_offset + file_size;
+ rel_offset = abs_offset + LZX_WIM_MAGIC_FILESIZE;
}
*call_insn_target = cpu_to_le32(rel_offset);
}
* as it is used in calculating the translated jump targets. But in WIM files,
* this file size is always the same (LZX_WIM_MAGIC_FILESIZE == 12000000).*/
static void
-undo_call_insn_preprocessing(u8 uncompressed_data[], int uncompressed_data_len)
+undo_call_insn_preprocessing(u8 *uncompressed_data, size_t uncompressed_size)
{
- for (int i = 0; i < uncompressed_data_len - 10; i++) {
- if (uncompressed_data[i] == 0xe8) {
- undo_call_insn_translation((u32*)&uncompressed_data[i + 1],
- i,
- LZX_WIM_MAGIC_FILESIZE);
- i += 4;
- }
+#ifdef __SSE2__
+
+ /* SSE2 vectorized implementation for x86_64. This speeds up LZX
+ * decompression by about 5-8% overall. (Usually --- the performance
+ * actually regresses slightly in the degenerate case that the data
+ * consists entirely of 0xe8 bytes.) */
+ __m128i *p128 = (__m128i *)uncompressed_data;
+ u32 valid_mask = 0xFFFFFFFF;
+
+ if (uncompressed_size >= 32 &&
+ ((uintptr_t)uncompressed_data % 16 == 0))
+ {
+ __m128i * const end128 = p128 + uncompressed_size / 16 - 1;
+
+ /* Create a vector of all 0xe8 bytes */
+ const __m128i e8_bytes = _mm_set1_epi8(0xe8);
+
+ /* Iterate through the 16-byte vectors in the input. */
+ do {
+ /* Compare the current 16-byte vector with the vector of
+ * all 0xe8 bytes. This produces 0xff where the byte is
+ * 0xe8 and 0x00 where it is not. */
+ __m128i cmpresult = _mm_cmpeq_epi8(*p128, e8_bytes);
+
+ /* Map the comparison results into a single 16-bit
+ * number. It will contain a 1 bit when the
+ * corresponding byte in the current 16-byte vector is
+ * an e8 byte. Note: the low-order bit corresponds to
+ * the first (lowest address) byte. */
+ u32 e8_mask = _mm_movemask_epi8(cmpresult);
+
+ if (!e8_mask) {
+ /* If e8_mask is 0, then none of these 16 bytes
+ * have value 0xe8. No e8 translation is
+ * needed, and there is no restriction that
+ * carries over to the next 16 bytes. */
+ valid_mask = 0xFFFFFFFF;
+ } else {
+ /* At least one byte has value 0xe8.
+ *
+ * The AND with valid_mask accounts for the fact
+ * that we can't start an e8 translation that
+ * overlaps the previous one. */
+ while ((e8_mask &= valid_mask)) {
+
+ /* Count the number of trailing zeroes
+ * in e8_mask. This will produce the
+ * index of the byte, within the 16, at
+ * which the next e8 translation should
+ * be done. */
+ u32 bit = __builtin_ctz(e8_mask);
+
+ /* Do the e8 translation. */
+ u8 *p8 = (u8 *)p128 + bit;
+ undo_call_insn_translation((s32 *)(p8 + 1),
+ p8 - uncompressed_data);
+
+ /* Don't start an e8 translation in the
+ * next 4 bytes. */
+ valid_mask &= ~((u32)0x1F << bit);
+ }
+ /* Moving on to the next vector. Shift and set
+ * valid_mask accordingly. */
+ valid_mask >>= 16;
+ valid_mask |= 0xFFFF0000;
+ }
+ } while (++p128 < end128);
+ }
+
+ u8 *p8 = (u8 *)p128;
+ while (!(valid_mask & 1)) {
+ p8++;
+ valid_mask >>= 1;
+ }
+#else /* __SSE2__ */
+ u8 *p8 = uncompressed_data;
+#endif /* !__SSE2__ */
+
+ if (uncompressed_size > 10) {
+ /* Finish any bytes that weren't processed by the vectorized
+ * implementation. */
+ u8 *p8_end = uncompressed_data + uncompressed_size - 10;
+ do {
+ if (*p8 == 0xe8) {
+ undo_call_insn_translation((s32 *)(p8 + 1),
+ p8 - uncompressed_data);
+ p8 += 5;
+ } else {
+ p8++;
+ }
+ } while (p8 < p8_end);
}
}
/*
- * Decompresses a LZX-compressed block of data from which the header has already
+ * Decompresses an LZX-compressed block of data from which the header has already
* been read.
*
* @block_type: The type of the block (LZX_BLOCKTYPE_VERBATIM or
- * LZX_BLOCKTYPE_ALIGNED)
+ * LZX_BLOCKTYPE_ALIGNED)
* @block_size: The size of the block, in bytes.
* @num_main_syms: Number of symbols in the main alphabet.
* @window: Pointer to the decompression window.
* @window_pos: The current position in the window. Will be 0 for the first
- * block.
+ * block.
* @tables: The Huffman decoding tables for the block (main, length, and
- * aligned offset, the latter only for LZX_BLOCKTYPE_ALIGNED)
+ * aligned offset, the latter only for LZX_BLOCKTYPE_ALIGNED)
* @queue: The least-recently-used queue for match offsets.
* @istream: The input bitstream for the compressed literals.
*/
return 0;
}
-/* API function documented in wimlib.h */
-WIMLIBAPI int
-wimlib_lzx_decompress2(const void *compressed_data, unsigned compressed_len,
- void *uncompressed_data, unsigned uncompressed_len,
- u32 max_window_size)
+static int
+lzx_decompress(const void *compressed_data, size_t compressed_size,
+ void *uncompressed_data, size_t uncompressed_size,
+ void *_ctx)
{
- struct lzx_tables tables;
+ struct lzx_decompressor *ctx = _ctx;
struct input_bitstream istream;
struct lzx_lru_queue queue;
unsigned window_pos;
unsigned block_size;
unsigned block_type;
- unsigned num_main_syms;
int ret;
bool e8_preprocessing_done;
- LZX_DEBUG("compressed_data = %p, compressed_len = %u, "
- "uncompressed_data = %p, uncompressed_len = %u, "
+ LZX_DEBUG("compressed_data = %p, compressed_size = %zu, "
+ "uncompressed_data = %p, uncompressed_size = %zu, "
"max_window_size=%u).",
- compressed_data, compressed_len,
- uncompressed_data, uncompressed_len, max_window_size);
+ compressed_data, compressed_size,
+ uncompressed_data, uncompressed_size,
+ ctx->max_window_size);
- if (!lzx_window_size_valid(max_window_size)) {
- LZX_DEBUG("Window size of %u is invalid!",
- max_window_size);
- return -1;
- }
-
- num_main_syms = lzx_get_num_main_syms(max_window_size);
-
- if (uncompressed_len > max_window_size) {
- LZX_DEBUG("Uncompressed chunk size of %u exceeds "
+ if (uncompressed_size > ctx->max_window_size) {
+ LZX_DEBUG("Uncompressed size of %zu exceeds "
"window size of %u!",
- uncompressed_len, max_window_size);
+ uncompressed_size, ctx->max_window_size);
return -1;
}
- memset(tables.maintree_lens, 0, sizeof(tables.maintree_lens));
- memset(tables.lentree_lens, 0, sizeof(tables.lentree_lens));
+ memset(ctx->tables.maintree_lens, 0, sizeof(ctx->tables.maintree_lens));
+ memset(ctx->tables.lentree_lens, 0, sizeof(ctx->tables.lentree_lens));
lzx_lru_queue_init(&queue);
- init_input_bitstream(&istream, compressed_data, compressed_len);
+ init_input_bitstream(&istream, compressed_data, compressed_size);
e8_preprocessing_done = false; /* Set to true if there may be 0xe8 bytes
in the uncompressed data. */
* blocks. */
for (window_pos = 0;
- window_pos < uncompressed_len;
+ window_pos < uncompressed_size;
window_pos += block_size)
{
LZX_DEBUG("Reading block header.");
- ret = lzx_read_block_header(&istream, num_main_syms,
- max_window_size, &block_size,
- &block_type, &tables, &queue);
+ ret = lzx_read_block_header(&istream, ctx->num_main_syms,
+ ctx->max_window_size, &block_size,
+ &block_type, &ctx->tables, &queue);
if (ret)
return ret;
LZX_DEBUG("block_size = %u, window_pos = %u",
block_size, window_pos);
- if (block_size > uncompressed_len - window_pos) {
+ if (block_size > uncompressed_size - window_pos) {
LZX_DEBUG("Expected a block size of at "
- "most %u bytes (found %u bytes)",
- uncompressed_len - window_pos, block_size);
+ "most %zu bytes (found %u bytes)",
+ uncompressed_size - window_pos, block_size);
return -1;
}
LZX_DEBUG("LZX_BLOCKTYPE_ALIGNED");
ret = lzx_decompress_block(block_type,
block_size,
- num_main_syms,
+ ctx->num_main_syms,
uncompressed_data,
window_pos,
- &tables,
+ &ctx->tables,
&queue,
&istream);
if (ret)
return ret;
- if (tables.maintree_lens[0xe8] != 0)
+ if (ctx->tables.maintree_lens[0xe8] != 0)
e8_preprocessing_done = true;
break;
case LZX_BLOCKTYPE_UNCOMPRESSED:
}
}
if (e8_preprocessing_done)
- undo_call_insn_preprocessing(uncompressed_data, uncompressed_len);
+ undo_call_insn_preprocessing(uncompressed_data, uncompressed_size);
return 0;
}
-/* API function documented in wimlib.h */
-WIMLIBAPI int
-wimlib_lzx_decompress(const void *compressed_data, unsigned compressed_len,
- void *uncompressed_data, unsigned uncompressed_len)
+static void
+lzx_free_decompressor(void *_ctx)
+{
+ struct lzx_decompressor *ctx = _ctx;
+
+ FREE(ctx);
+}
+
+static int
+lzx_create_decompressor(size_t max_window_size,
+ const struct wimlib_decompressor_params_header *params,
+ void **ctx_ret)
{
- return wimlib_lzx_decompress2(compressed_data, compressed_len,
- uncompressed_data, uncompressed_len,
- 32768);
+ struct lzx_decompressor *ctx;
+
+ if (!lzx_window_size_valid(max_window_size))
+ return WIMLIB_ERR_INVALID_PARAM;
+
+ ctx = MALLOC(sizeof(struct lzx_decompressor));
+ if (ctx == NULL)
+ return WIMLIB_ERR_NOMEM;
+
+ ctx->max_window_size = max_window_size;
+ ctx->num_main_syms = lzx_get_num_main_syms(max_window_size);
+
+ *ctx_ret = ctx;
+ return 0;
}
+
+const struct decompressor_ops lzx_decompressor_ops = {
+ .create_decompressor = lzx_create_decompressor,
+ .decompress = lzx_decompress,
+ .free_decompressor = lzx_free_decompressor,
+};
git://wimlib.net / wimlib / blobdiff