#include <string.h>
-#ifdef __SSE2__
-# include <emmintrin.h>
-#endif
-
/* Huffman decoding tables and maps from symbols to code lengths. */
struct lzx_tables {
*/
static inline u16
read_huffsym_using_pretree(struct input_bitstream *istream,
- const u16 pretree_decode_table[],
- const u8 pretree_lens[])
+ const u16 pretree_decode_table[])
{
- return read_huffsym(istream, pretree_decode_table, pretree_lens,
- LZX_PRECODE_NUM_SYMBOLS, LZX_PRECODE_TABLEBITS,
- LZX_MAX_PRE_CODEWORD_LEN);
+ return read_huffsym(istream, pretree_decode_table,
+ LZX_PRECODE_TABLEBITS, LZX_MAX_PRE_CODEWORD_LEN);
}
/* Reads a Huffman-encoded symbol using the main tree. */
static inline u16
read_huffsym_using_maintree(struct input_bitstream *istream,
- const struct lzx_tables *tables,
- unsigned num_main_syms)
+ const struct lzx_tables *tables)
{
return read_huffsym(istream, tables->maintree_decode_table,
- tables->maintree_lens, num_main_syms,
LZX_MAINCODE_TABLEBITS, LZX_MAX_MAIN_CODEWORD_LEN);
}
const struct lzx_tables *tables)
{
return read_huffsym(istream, tables->lentree_decode_table,
- tables->lentree_lens, LZX_LENCODE_NUM_SYMBOLS,
LZX_LENCODE_TABLEBITS, LZX_MAX_LEN_CODEWORD_LEN);
}
const struct lzx_tables *tables)
{
return read_huffsym(istream, tables->alignedtree_decode_table,
- tables->alignedtree_lens,
- LZX_ALIGNEDCODE_NUM_SYMBOLS,
- LZX_ALIGNEDCODE_TABLEBITS,
- LZX_MAX_ALIGNED_CODEWORD_LEN);
+ LZX_ALIGNEDCODE_TABLEBITS, LZX_MAX_ALIGNED_CODEWORD_LEN);
}
/*
signed char value;
tree_code = read_huffsym_using_pretree(istream,
- pretree_decode_table,
- pretree_lens);
+ pretree_decode_table);
switch (tree_code) {
case 17: /* Run of 0's */
num_zeroes = bitstream_read_bits(istream, 4);
num_same = bitstream_read_bits(istream, 1);
num_same += 4;
code = read_huffsym_using_pretree(istream,
- pretree_decode_table,
- pretree_lens);
+ pretree_decode_table);
value = (signed char)*lens - (signed char)code;
if (value < 0)
value += 17;
/* If the position_slot is 0, 1, or 2, the match offset is retrieved
* from the LRU queue. Otherwise, the match offset is not in the LRU
* queue. */
- switch (position_slot) {
- case 0:
- match_offset = queue->R[0];
- break;
- case 1:
- match_offset = queue->R[1];
- swap(queue->R[0], queue->R[1]);
- break;
- case 2:
- /* The queue doesn't work quite the same as a real LRU queue,
- * since using the R2 offset doesn't bump the R1 offset down to
- * R2. */
- match_offset = queue->R[2];
- swap(queue->R[0], queue->R[2]);
- break;
- default:
+ if (position_slot <= 2) {
+ /* Note: This isn't a real LRU queue, since using the R2 offset
+ * doesn't bump the R1 offset down to R2. This quirk allows all
+ * 3 recent offsets to be handled by the same code. (For R0,
+ * the swap is a no-op.) */
+ match_offset = queue->R[position_slot];
+ queue->R[position_slot] = queue->R[0];
+ queue->R[0] = match_offset;
+ } else {
/* Otherwise, the offset was not encoded as one the offsets in
* the queue. Depending on the position slot, there is a
* certain number of extra bits that need to be read to fully
queue->R[2] = queue->R[1];
queue->R[1] = queue->R[0];
queue->R[0] = match_offset;
- break;
}
/* Verify that the match is in the bounds of the part of the window
return match_len;
}
-static void
-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 < LZX_WIM_MAGIC_FILESIZE) {
- if (abs_offset >= 0) {
- /* "good translation" */
- rel_offset = abs_offset - input_pos;
- } else {
- /* "compensating translation" */
- rel_offset = abs_offset + LZX_WIM_MAGIC_FILESIZE;
- }
- *call_insn_target = cpu_to_le32(rel_offset);
- }
-}
-
-/* Undo the 'E8' preprocessing, where the targets of x86 CALL instructions were
- * changed from relative offsets to absolute offsets.
- *
- * Note that this call instruction preprocessing can and will be used on any
- * data even if it is not actually x86 machine code. In fact, this type of
- * preprocessing appears to always be used in LZX-compressed resources in WIM
- * files; there is no bit to indicate whether it is used or not, unlike in the
- * LZX compressed format as used in cabinet files, where a bit is reserved for
- * that purpose.
- *
- * Call instruction preprocessing is disabled in the last 6 bytes of the
- * uncompressed data, which really means the 5-byte call instruction cannot
- * start in the last 10 bytes of the uncompressed data. This is one of the
- * errors in the LZX documentation.
- *
- * Call instruction preprocessing does not appear to be disabled after the
- * 32768th chunk of a WIM stream, which is apparently is yet another difference
- * from the LZX compression used in cabinet files.
- *
- * Call instruction processing is supposed to take the file size as a parameter,
- * 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, size_t uncompressed_size)
-{
-#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 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)
* @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.
*/
static int
lzx_decompress_block(int block_type, unsigned block_size,
- unsigned num_main_syms,
u8 *window,
unsigned window_pos,
const struct lzx_tables *tables,
end = window_pos + block_size;
while (window_pos < end) {
- main_element = read_huffsym_using_maintree(istream, tables,
- num_main_syms);
+ main_element = read_huffsym_using_maintree(istream, tables);
if (main_element < LZX_NUM_CHARS) {
/* literal: 0 to LZX_NUM_CHARS - 1 */
window[window_pos++] = main_element;
LZX_DEBUG("LZX_BLOCKTYPE_ALIGNED");
ret = lzx_decompress_block(block_type,
block_size,
- ctx->num_main_syms,
uncompressed_data,
window_pos,
&ctx->tables,
}
}
if (e8_preprocessing_done)
- undo_call_insn_preprocessing(uncompressed_data, uncompressed_size);
+ lzx_undo_e8_preprocessing(uncompressed_data, uncompressed_size);
return 0;
}
{
struct lzx_decompressor *ctx = _ctx;
- FREE(ctx);
+ ALIGNED_FREE(ctx);
}
static int
if (!lzx_window_size_valid(max_window_size))
return WIMLIB_ERR_INVALID_PARAM;
- ctx = MALLOC(sizeof(struct lzx_decompressor));
+ ctx = ALIGNED_MALLOC(sizeof(struct lzx_decompressor),
+ DECODE_TABLE_ALIGNMENT);
if (ctx == NULL)
return WIMLIB_ERR_NOMEM;
git://wimlib.net / wimlib / blobdiff