unlzma: speedup, by Pascal Bellard (pascal.bellard AT ads-lu.com)
LZMA_FAST off: 10% faster and: function old new delta rc_is_bit_1 - 92 +92 rc_do_normalize 45 81 +36 rc_update_bit_1 25 - -25 rc_update_bit_0 30 - -30 rc_is_bit_0_helper 38 - -38 rc_get_bit 60 17 -43 rc_read 48 - -48 unpack_lzma_stream 1768 1517 -251 ------------------------------------------------------------------------------ (add/remove: 1/4 grow/shrink: 1/2 up/down: 128/-435) Total: -307 bytes LZMA_FAST on: 14% faster and: unpack_lzma_stream 2301 2737 +436 rc_get_bit 106 - -106
This commit is contained in:
Denis Vlasenko
parent
6fb5f01c0b
commit
9ac3dc764a
@ -283,8 +283,8 @@ config FEATURE_LZMA_FAST
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default n
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depends on UNLZMA
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help
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This option reduces decompression time by about 33% at the cost of
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a 2K bigger binary.
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This option reduces decompression time by about 25% at the cost of
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a 1K bigger binary.
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config UNZIP
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bool "unzip"
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@ -8,14 +8,15 @@
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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#include "libbb.h"
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#include "unarchive.h"
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#if ENABLE_FEATURE_LZMA_FAST
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# define speed_inline ALWAYS_INLINE
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# define size_inline
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#else
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# define speed_inline
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# define size_inline ALWAYS_INLINE
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#endif
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@ -44,8 +45,8 @@ typedef struct {
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#define RC_MODEL_TOTAL_BITS 11
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/* Called twice: once at startup and once in rc_normalize() */
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static void rc_read(rc_t *rc)
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/* Called twice: once at startup (LZMA_FAST only) and once in rc_normalize() */
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static size_inline void rc_read(rc_t *rc)
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{
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int buffer_size = safe_read(rc->fd, RC_BUFFER, RC_BUFFER_SIZE);
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if (buffer_size <= 0)
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@ -54,8 +55,17 @@ static void rc_read(rc_t *rc)
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rc->buffer_end = RC_BUFFER + buffer_size;
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}
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/* Called twice, but one callsite is in speed_inline'd rc_is_bit_1() */
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static void rc_do_normalize(rc_t *rc)
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{
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if (rc->ptr >= rc->buffer_end)
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rc_read(rc);
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rc->range <<= 8;
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rc->code = (rc->code << 8) | *rc->ptr++;
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}
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/* Called once */
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static rc_t* rc_init(int fd) /*, int buffer_size) */
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static ALWAYS_INLINE rc_t* rc_init(int fd) /*, int buffer_size) */
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{
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int i;
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rc_t *rc;
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@ -63,17 +73,18 @@ static rc_t* rc_init(int fd) /*, int buffer_size) */
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rc = xmalloc(sizeof(*rc) + RC_BUFFER_SIZE);
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rc->fd = fd;
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/* rc->buffer_size = buffer_size; */
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rc->buffer_end = RC_BUFFER + RC_BUFFER_SIZE;
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rc->ptr = rc->buffer_end;
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rc->code = 0;
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rc->range = 0xFFFFFFFF;
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for (i = 0; i < 5; i++) {
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#if ENABLE_FEATURE_LZMA_FAST
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if (rc->ptr >= rc->buffer_end)
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rc_read(rc);
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rc->code = (rc->code << 8) | *rc->ptr++;
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#else
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rc_do_normalize(rc);
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#endif
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}
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rc->range = 0xFFFFFFFF;
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return rc;
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}
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@ -83,14 +94,6 @@ static ALWAYS_INLINE void rc_free(rc_t *rc)
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free(rc);
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}
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/* Called twice, but one callsite is in speed_inline'd rc_is_bit_0_helper() */
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static void rc_do_normalize(rc_t *rc)
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{
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if (rc->ptr >= rc->buffer_end)
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rc_read(rc);
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rc->range <<= 8;
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rc->code = (rc->code << 8) | *rc->ptr++;
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}
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static ALWAYS_INLINE void rc_normalize(rc_t *rc)
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{
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if (rc->range < (1 << RC_TOP_BITS)) {
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@ -98,49 +101,28 @@ static ALWAYS_INLINE void rc_normalize(rc_t *rc)
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}
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}
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/* rc_is_bit_0 is called 9 times */
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/* Why rc_is_bit_0_helper exists?
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* Because we want to always expose (rc->code < rc->bound) to optimizer.
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* Thus rc_is_bit_0 is always inlined, and rc_is_bit_0_helper is inlined
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* only if we compile for speed.
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*/
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static speed_inline uint32_t rc_is_bit_0_helper(rc_t *rc, uint16_t *p)
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/* rc_is_bit_1 is called 9 times */
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static speed_inline int rc_is_bit_1(rc_t *rc, uint16_t *p)
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{
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rc_normalize(rc);
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rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS);
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return rc->bound;
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}
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static ALWAYS_INLINE int rc_is_bit_0(rc_t *rc, uint16_t *p)
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{
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uint32_t t = rc_is_bit_0_helper(rc, p);
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return rc->code < t;
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}
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/* Called ~10 times, but very small, thus inlined */
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static speed_inline void rc_update_bit_0(rc_t *rc, uint16_t *p)
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{
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rc->range = rc->bound;
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*p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
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}
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static speed_inline void rc_update_bit_1(rc_t *rc, uint16_t *p)
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{
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if (rc->code < rc->bound) {
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rc->range = rc->bound;
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*p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
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return 0;
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}
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rc->range -= rc->bound;
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rc->code -= rc->bound;
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*p -= *p >> RC_MOVE_BITS;
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return 1;
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}
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/* Called 4 times in unlzma loop */
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static int rc_get_bit(rc_t *rc, uint16_t *p, int *symbol)
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static speed_inline int rc_get_bit(rc_t *rc, uint16_t *p, int *symbol)
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{
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if (rc_is_bit_0(rc, p)) {
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rc_update_bit_0(rc, p);
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*symbol *= 2;
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return 0;
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} else {
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rc_update_bit_1(rc, p);
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*symbol = *symbol * 2 + 1;
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return 1;
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}
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int ret = rc_is_bit_1(rc, p);
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*symbol = *symbol * 2 + ret;
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return ret;
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}
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/* Called once */
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@ -266,13 +248,13 @@ unpack_lzma_stream(int src_fd, int dst_fd)
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header.dst_size = SWAP_LE64(header.dst_size);
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if (header.dict_size == 0)
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header.dict_size = 1;
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header.dict_size++;
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buffer = xmalloc(MIN(header.dst_size, header.dict_size));
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num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
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p = xmalloc(num_probs * sizeof(*p));
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num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
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num_probs += LZMA_LITERAL - LZMA_BASE_SIZE;
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for (i = 0; i < num_probs; i++)
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p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;
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@ -282,9 +264,8 @@ unpack_lzma_stream(int src_fd, int dst_fd)
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int pos_state = (buffer_pos + global_pos) & pos_state_mask;
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prob = p + LZMA_IS_MATCH + (state << LZMA_NUM_POS_BITS_MAX) + pos_state;
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if (rc_is_bit_0(rc, prob)) {
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if (!rc_is_bit_1(rc, prob)) {
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mi = 1;
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rc_update_bit_0(rc, prob);
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prob = (p + LZMA_LITERAL
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+ (LZMA_LIT_SIZE * ((((buffer_pos + global_pos) & literal_pos_mask) << lc)
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+ (previous_byte >> (8 - lc))
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@ -340,27 +321,21 @@ unpack_lzma_stream(int src_fd, int dst_fd)
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int offset;
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uint16_t *prob_len;
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rc_update_bit_1(rc, prob);
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prob = p + LZMA_IS_REP + state;
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if (rc_is_bit_0(rc, prob)) {
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rc_update_bit_0(rc, prob);
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if (!rc_is_bit_1(rc, prob)) {
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rep3 = rep2;
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rep2 = rep1;
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rep1 = rep0;
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state = state < LZMA_NUM_LIT_STATES ? 0 : 3;
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prob = p + LZMA_LEN_CODER;
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} else {
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rc_update_bit_1(rc, prob);
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prob = p + LZMA_IS_REP_G0 + state;
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if (rc_is_bit_0(rc, prob)) {
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rc_update_bit_0(rc, prob);
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prob += LZMA_IS_REP_G0 - LZMA_IS_REP;
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if (!rc_is_bit_1(rc, prob)) {
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prob = (p + LZMA_IS_REP_0_LONG
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+ (state << LZMA_NUM_POS_BITS_MAX)
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+ pos_state
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);
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if (rc_is_bit_0(rc, prob)) {
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rc_update_bit_0(rc, prob);
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if (!rc_is_bit_1(rc, prob)) {
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state = state < LZMA_NUM_LIT_STATES ? 9 : 11;
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#if ENABLE_FEATURE_LZMA_FAST
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pos = buffer_pos - rep0;
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@ -372,25 +347,16 @@ unpack_lzma_stream(int src_fd, int dst_fd)
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len = 1;
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goto string;
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#endif
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} else {
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rc_update_bit_1(rc, prob);
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}
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} else {
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uint32_t distance;
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rc_update_bit_1(rc, prob);
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prob = p + LZMA_IS_REP_G1 + state;
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if (rc_is_bit_0(rc, prob)) {
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rc_update_bit_0(rc, prob);
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distance = rep1;
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} else {
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rc_update_bit_1(rc, prob);
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prob = p + LZMA_IS_REP_G2 + state;
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if (rc_is_bit_0(rc, prob)) {
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rc_update_bit_0(rc, prob);
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distance = rep2;
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} else {
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rc_update_bit_1(rc, prob);
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prob += LZMA_IS_REP_G1 - LZMA_IS_REP_G0;
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distance = rep1;
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if (rc_is_bit_1(rc, prob)) {
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prob += LZMA_IS_REP_G2 - LZMA_IS_REP_G1;
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distance = rep2;
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if (rc_is_bit_1(rc, prob)) {
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distance = rep3;
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rep3 = rep2;
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}
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@ -404,24 +370,20 @@ unpack_lzma_stream(int src_fd, int dst_fd)
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}
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prob_len = prob + LZMA_LEN_CHOICE;
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if (rc_is_bit_0(rc, prob_len)) {
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rc_update_bit_0(rc, prob_len);
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prob_len = (prob + LZMA_LEN_LOW
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+ (pos_state << LZMA_LEN_NUM_LOW_BITS));
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if (!rc_is_bit_1(rc, prob_len)) {
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prob_len += LZMA_LEN_LOW - LZMA_LEN_CHOICE
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+ (pos_state << LZMA_LEN_NUM_LOW_BITS);
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offset = 0;
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num_bits = LZMA_LEN_NUM_LOW_BITS;
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} else {
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rc_update_bit_1(rc, prob_len);
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prob_len = prob + LZMA_LEN_CHOICE_2;
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if (rc_is_bit_0(rc, prob_len)) {
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rc_update_bit_0(rc, prob_len);
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prob_len = (prob + LZMA_LEN_MID
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+ (pos_state << LZMA_LEN_NUM_MID_BITS));
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prob_len += LZMA_LEN_CHOICE_2 - LZMA_LEN_CHOICE;
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if (!rc_is_bit_1(rc, prob_len)) {
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prob_len += LZMA_LEN_MID - LZMA_LEN_CHOICE_2
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+ (pos_state << LZMA_LEN_NUM_MID_BITS);
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offset = 1 << LZMA_LEN_NUM_LOW_BITS;
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num_bits = LZMA_LEN_NUM_MID_BITS;
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} else {
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rc_update_bit_1(rc, prob_len);
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prob_len = prob + LZMA_LEN_HIGH;
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prob_len += LZMA_LEN_HIGH - LZMA_LEN_CHOICE_2;
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offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
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+ (1 << LZMA_LEN_NUM_MID_BITS));
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num_bits = LZMA_LEN_NUM_HIGH_BITS;
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@ -438,19 +400,20 @@ unpack_lzma_stream(int src_fd, int dst_fd)
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((len < LZMA_NUM_LEN_TO_POS_STATES ? len :
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LZMA_NUM_LEN_TO_POS_STATES - 1)
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<< LZMA_NUM_POS_SLOT_BITS);
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rc_bit_tree_decode(rc, prob, LZMA_NUM_POS_SLOT_BITS,
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&pos_slot);
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rc_bit_tree_decode(rc, prob,
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LZMA_NUM_POS_SLOT_BITS, &pos_slot);
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rep0 = pos_slot;
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if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
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num_bits = (pos_slot >> 1) - 1;
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rep0 = 2 | (pos_slot & 1);
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prob = p + LZMA_ALIGN;
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if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
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rep0 <<= num_bits;
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prob = p + LZMA_SPEC_POS + rep0 - pos_slot - 1;
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prob += LZMA_SPEC_POS - LZMA_ALIGN - 1 + rep0 - pos_slot;
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} else {
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num_bits -= LZMA_NUM_ALIGN_BITS;
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while (num_bits--)
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rep0 = (rep0 << 1) | rc_direct_bit(rc);
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prob = p + LZMA_ALIGN;
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rep0 <<= LZMA_NUM_ALIGN_BITS;
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num_bits = LZMA_NUM_ALIGN_BITS;
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}
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@ -461,8 +424,7 @@ unpack_lzma_stream(int src_fd, int dst_fd)
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rep0 |= i;
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i <<= 1;
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}
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} else
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rep0 = pos_slot;
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}
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if (++rep0 == 0)
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break;
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}
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