From: Denys Vlasenko Date: Sun, 6 Sep 2009 13:06:25 +0000 (+0200) Subject: Revert "unlzma: speedup, by Pascal Bellard (pascal.bellard AT ads-lu.com)" X-Git-Tag: 1_16_0~513 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=3de3f57c6d0200b49a5e31e80421e36272035e15;p=oweals%2Fbusybox.git Revert "unlzma: speedup, by Pascal Bellard (pascal.bellard AT ads-lu.com)" https://bugs.busybox.net/show_bug.cgi?id=599 This reverts commit 9ac3dc764a78b51fe8fdcd1b4682850de098733b. --- diff --git a/archival/Config.in b/archival/Config.in index cae7f20bb..71b953819 100644 --- a/archival/Config.in +++ b/archival/Config.in @@ -298,8 +298,8 @@ config FEATURE_LZMA_FAST default n depends on UNLZMA help - This option reduces decompression time by about 25% at the cost of - a 1K bigger binary. + This option reduces decompression time by about 33% at the cost of + a 2K bigger binary. config UNZIP bool "unzip" diff --git a/archival/libunarchive/decompress_unlzma.c b/archival/libunarchive/decompress_unlzma.c index 68085d68c..33e5cd65d 100644 --- a/archival/libunarchive/decompress_unlzma.c +++ b/archival/libunarchive/decompress_unlzma.c @@ -8,15 +8,14 @@ * * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. */ + #include "libbb.h" #include "unarchive.h" #if ENABLE_FEATURE_LZMA_FAST # define speed_inline ALWAYS_INLINE -# define size_inline #else # define speed_inline -# define size_inline ALWAYS_INLINE #endif @@ -45,8 +44,8 @@ typedef struct { #define RC_MODEL_TOTAL_BITS 11 -/* Called twice: once at startup (LZMA_FAST only) and once in rc_normalize() */ -static size_inline void rc_read(rc_t *rc) +/* Called twice: once at startup and once in rc_normalize() */ +static void rc_read(rc_t *rc) { int buffer_size = safe_read(rc->fd, RC_BUFFER, RC_BUFFER_SIZE); if (buffer_size <= 0) @@ -55,17 +54,8 @@ static size_inline void rc_read(rc_t *rc) rc->buffer_end = RC_BUFFER + buffer_size; } -/* Called twice, but one callsite is in speed_inline'd rc_is_bit_1() */ -static void rc_do_normalize(rc_t *rc) -{ - if (rc->ptr >= rc->buffer_end) - rc_read(rc); - rc->range <<= 8; - rc->code = (rc->code << 8) | *rc->ptr++; -} - /* Called once */ -static ALWAYS_INLINE rc_t* rc_init(int fd) /*, int buffer_size) */ +static rc_t* rc_init(int fd) /*, int buffer_size) */ { int i; rc_t *rc; @@ -73,18 +63,17 @@ static ALWAYS_INLINE rc_t* rc_init(int fd) /*, int buffer_size) */ rc = xmalloc(sizeof(*rc) + RC_BUFFER_SIZE); rc->fd = fd; + /* rc->buffer_size = buffer_size; */ + rc->buffer_end = RC_BUFFER + RC_BUFFER_SIZE; rc->ptr = rc->buffer_end; + rc->code = 0; + rc->range = 0xFFFFFFFF; for (i = 0; i < 5; i++) { -#if ENABLE_FEATURE_LZMA_FAST if (rc->ptr >= rc->buffer_end) rc_read(rc); rc->code = (rc->code << 8) | *rc->ptr++; -#else - rc_do_normalize(rc); -#endif } - rc->range = 0xFFFFFFFF; return rc; } @@ -94,6 +83,14 @@ static ALWAYS_INLINE void rc_free(rc_t *rc) free(rc); } +/* Called twice, but one callsite is in speed_inline'd rc_is_bit_0_helper() */ +static void rc_do_normalize(rc_t *rc) +{ + if (rc->ptr >= rc->buffer_end) + rc_read(rc); + rc->range <<= 8; + rc->code = (rc->code << 8) | *rc->ptr++; +} static ALWAYS_INLINE void rc_normalize(rc_t *rc) { if (rc->range < (1 << RC_TOP_BITS)) { @@ -101,28 +98,49 @@ static ALWAYS_INLINE void rc_normalize(rc_t *rc) } } -/* rc_is_bit_1 is called 9 times */ -static speed_inline int rc_is_bit_1(rc_t *rc, uint16_t *p) +/* rc_is_bit_0 is called 9 times */ +/* Why rc_is_bit_0_helper exists? + * Because we want to always expose (rc->code < rc->bound) to optimizer. + * Thus rc_is_bit_0 is always inlined, and rc_is_bit_0_helper is inlined + * only if we compile for speed. + */ +static speed_inline uint32_t rc_is_bit_0_helper(rc_t *rc, uint16_t *p) { rc_normalize(rc); rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS); - if (rc->code < rc->bound) { - rc->range = rc->bound; - *p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS; - return 0; - } + return rc->bound; +} +static ALWAYS_INLINE int rc_is_bit_0(rc_t *rc, uint16_t *p) +{ + uint32_t t = rc_is_bit_0_helper(rc, p); + return rc->code < t; +} + +/* Called ~10 times, but very small, thus inlined */ +static speed_inline void rc_update_bit_0(rc_t *rc, uint16_t *p) +{ + rc->range = rc->bound; + *p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS; +} +static speed_inline void rc_update_bit_1(rc_t *rc, uint16_t *p) +{ rc->range -= rc->bound; rc->code -= rc->bound; *p -= *p >> RC_MOVE_BITS; - return 1; } /* Called 4 times in unlzma loop */ -static speed_inline int rc_get_bit(rc_t *rc, uint16_t *p, int *symbol) +static int rc_get_bit(rc_t *rc, uint16_t *p, int *symbol) { - int ret = rc_is_bit_1(rc, p); - *symbol = *symbol * 2 + ret; - return ret; + if (rc_is_bit_0(rc, p)) { + rc_update_bit_0(rc, p); + *symbol *= 2; + return 0; + } else { + rc_update_bit_1(rc, p); + *symbol = *symbol * 2 + 1; + return 1; + } } /* Called once */ @@ -248,13 +266,13 @@ unpack_lzma_stream(int src_fd, int dst_fd) header.dst_size = SWAP_LE64(header.dst_size); if (header.dict_size == 0) - header.dict_size++; + header.dict_size = 1; buffer = xmalloc(MIN(header.dst_size, header.dict_size)); num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp)); p = xmalloc(num_probs * sizeof(*p)); - num_probs += LZMA_LITERAL - LZMA_BASE_SIZE; + num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp)); for (i = 0; i < num_probs; i++) p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1; @@ -264,8 +282,9 @@ unpack_lzma_stream(int src_fd, int dst_fd) int pos_state = (buffer_pos + global_pos) & pos_state_mask; prob = p + LZMA_IS_MATCH + (state << LZMA_NUM_POS_BITS_MAX) + pos_state; - if (!rc_is_bit_1(rc, prob)) { + if (rc_is_bit_0(rc, prob)) { mi = 1; + rc_update_bit_0(rc, prob); prob = (p + LZMA_LITERAL + (LZMA_LIT_SIZE * ((((buffer_pos + global_pos) & literal_pos_mask) << lc) + (previous_byte >> (8 - lc)) @@ -321,21 +340,27 @@ unpack_lzma_stream(int src_fd, int dst_fd) int offset; uint16_t *prob_len; + rc_update_bit_1(rc, prob); prob = p + LZMA_IS_REP + state; - if (!rc_is_bit_1(rc, prob)) { + if (rc_is_bit_0(rc, prob)) { + rc_update_bit_0(rc, prob); rep3 = rep2; rep2 = rep1; rep1 = rep0; state = state < LZMA_NUM_LIT_STATES ? 0 : 3; prob = p + LZMA_LEN_CODER; } else { - prob += LZMA_IS_REP_G0 - LZMA_IS_REP; - if (!rc_is_bit_1(rc, prob)) { + rc_update_bit_1(rc, prob); + prob = p + LZMA_IS_REP_G0 + state; + if (rc_is_bit_0(rc, prob)) { + rc_update_bit_0(rc, prob); prob = (p + LZMA_IS_REP_0_LONG + (state << LZMA_NUM_POS_BITS_MAX) + pos_state ); - if (!rc_is_bit_1(rc, prob)) { + if (rc_is_bit_0(rc, prob)) { + rc_update_bit_0(rc, prob); + state = state < LZMA_NUM_LIT_STATES ? 9 : 11; #if ENABLE_FEATURE_LZMA_FAST pos = buffer_pos - rep0; @@ -347,16 +372,25 @@ unpack_lzma_stream(int src_fd, int dst_fd) len = 1; goto string; #endif + } else { + rc_update_bit_1(rc, prob); } } else { uint32_t distance; - prob += LZMA_IS_REP_G1 - LZMA_IS_REP_G0; - distance = rep1; - if (rc_is_bit_1(rc, prob)) { - prob += LZMA_IS_REP_G2 - LZMA_IS_REP_G1; - distance = rep2; - if (rc_is_bit_1(rc, prob)) { + rc_update_bit_1(rc, prob); + prob = p + LZMA_IS_REP_G1 + state; + if (rc_is_bit_0(rc, prob)) { + rc_update_bit_0(rc, prob); + distance = rep1; + } else { + rc_update_bit_1(rc, prob); + prob = p + LZMA_IS_REP_G2 + state; + if (rc_is_bit_0(rc, prob)) { + rc_update_bit_0(rc, prob); + distance = rep2; + } else { + rc_update_bit_1(rc, prob); distance = rep3; rep3 = rep2; } @@ -370,20 +404,24 @@ unpack_lzma_stream(int src_fd, int dst_fd) } prob_len = prob + LZMA_LEN_CHOICE; - if (!rc_is_bit_1(rc, prob_len)) { - prob_len += LZMA_LEN_LOW - LZMA_LEN_CHOICE - + (pos_state << LZMA_LEN_NUM_LOW_BITS); + if (rc_is_bit_0(rc, prob_len)) { + rc_update_bit_0(rc, prob_len); + prob_len = (prob + LZMA_LEN_LOW + + (pos_state << LZMA_LEN_NUM_LOW_BITS)); offset = 0; num_bits = LZMA_LEN_NUM_LOW_BITS; } else { - prob_len += LZMA_LEN_CHOICE_2 - LZMA_LEN_CHOICE; - if (!rc_is_bit_1(rc, prob_len)) { - prob_len += LZMA_LEN_MID - LZMA_LEN_CHOICE_2 - + (pos_state << LZMA_LEN_NUM_MID_BITS); + rc_update_bit_1(rc, prob_len); + prob_len = prob + LZMA_LEN_CHOICE_2; + if (rc_is_bit_0(rc, prob_len)) { + rc_update_bit_0(rc, prob_len); + prob_len = (prob + LZMA_LEN_MID + + (pos_state << LZMA_LEN_NUM_MID_BITS)); offset = 1 << LZMA_LEN_NUM_LOW_BITS; num_bits = LZMA_LEN_NUM_MID_BITS; } else { - prob_len += LZMA_LEN_HIGH - LZMA_LEN_CHOICE_2; + rc_update_bit_1(rc, prob_len); + prob_len = prob + LZMA_LEN_HIGH; offset = ((1 << LZMA_LEN_NUM_LOW_BITS) + (1 << LZMA_LEN_NUM_MID_BITS)); num_bits = LZMA_LEN_NUM_HIGH_BITS; @@ -400,20 +438,19 @@ unpack_lzma_stream(int src_fd, int dst_fd) ((len < LZMA_NUM_LEN_TO_POS_STATES ? len : LZMA_NUM_LEN_TO_POS_STATES - 1) << LZMA_NUM_POS_SLOT_BITS); - rc_bit_tree_decode(rc, prob, - LZMA_NUM_POS_SLOT_BITS, &pos_slot); - rep0 = pos_slot; + rc_bit_tree_decode(rc, prob, LZMA_NUM_POS_SLOT_BITS, + &pos_slot); if (pos_slot >= LZMA_START_POS_MODEL_INDEX) { num_bits = (pos_slot >> 1) - 1; rep0 = 2 | (pos_slot & 1); - prob = p + LZMA_ALIGN; if (pos_slot < LZMA_END_POS_MODEL_INDEX) { rep0 <<= num_bits; - prob += LZMA_SPEC_POS - LZMA_ALIGN - 1 + rep0 - pos_slot; + prob = p + LZMA_SPEC_POS + rep0 - pos_slot - 1; } else { num_bits -= LZMA_NUM_ALIGN_BITS; while (num_bits--) rep0 = (rep0 << 1) | rc_direct_bit(rc); + prob = p + LZMA_ALIGN; rep0 <<= LZMA_NUM_ALIGN_BITS; num_bits = LZMA_NUM_ALIGN_BITS; } @@ -424,7 +461,8 @@ unpack_lzma_stream(int src_fd, int dst_fd) rep0 |= i; i <<= 1; } - } + } else + rep0 = pos_slot; if (++rep0 == 0) break; }