unlzma: fixed speedup/shrink by Pascal Bellard (pascal.bellard AT ads-lu.com)
authorDenys Vlasenko <vda.linux@googlemail.com>
Tue, 15 Sep 2009 21:40:08 +0000 (23:40 +0200)
committerDenys Vlasenko <vda.linux@googlemail.com>
Tue, 15 Sep 2009 21:40:08 +0000 (23:40 +0200)
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
archival/Config.in
archival/libunarchive/decompress_unlzma.c

index 71b95381998d9054c44feb2542786966f815a782..cae7f20bbe2c07a7294338f8094bd3fbaa0fc550 100644 (file)
@@ -298,8 +298,8 @@ config FEATURE_LZMA_FAST
        default n
        depends on UNLZMA
        help
-         This option reduces decompression time by about 33% at the cost of
-         a 2K bigger binary.
+         This option reduces decompression time by about 25% at the cost of
+         a 1K bigger binary.
 
 config UNZIP
        bool "unzip"
index 33e5cd65d40c58d8d9029000789b5bed444d806e..4478cd2e3b0b5dd02d619b5bec881dc49354af07 100644 (file)
@@ -8,14 +8,15 @@
  *
  * 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
 
 
@@ -44,36 +45,48 @@ typedef struct {
 #define RC_MODEL_TOTAL_BITS 11
 
 
-/* Called twice: once at startup and once in rc_normalize() */
-static void rc_read(rc_t *rc)
+/* Called twice: once at startup (LZMA_FAST only) and once in rc_normalize() */
+static size_inline void rc_read(rc_t *rc)
 {
        int buffer_size = safe_read(rc->fd, RC_BUFFER, RC_BUFFER_SIZE);
+//TODO: return -1 instead
+//This will make unlzma delete broken unpacked file on unpack errors
        if (buffer_size <= 0)
                bb_error_msg_and_die("unexpected EOF");
        rc->ptr = RC_BUFFER;
        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 rc_t* rc_init(int fd) /*, int buffer_size) */
+static ALWAYS_INLINE rc_t* rc_init(int fd) /*, int buffer_size) */
 {
        int i;
        rc_t *rc;
 
-       rc = xmalloc(sizeof(*rc) + RC_BUFFER_SIZE);
+       rc = xzalloc(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->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;
 }
 
@@ -83,14 +96,6 @@ 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)) {
@@ -98,49 +103,28 @@ static ALWAYS_INLINE void rc_normalize(rc_t *rc)
        }
 }
 
-/* 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_is_bit_1 is called 9 times */
+static speed_inline int rc_is_bit_1(rc_t *rc, uint16_t *p)
 {
        rc_normalize(rc);
        rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS);
-       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)
-{
+       if (rc->code < rc->bound) {
+               rc->range = rc->bound;
+               *p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
+               return 0;
+       }
        rc->range -= rc->bound;
        rc->code -= rc->bound;
        *p -= *p >> RC_MOVE_BITS;
+       return 1;
 }
 
 /* Called 4 times in unlzma loop */
-static int rc_get_bit(rc_t *rc, uint16_t *p, int *symbol)
+static speed_inline int rc_get_bit(rc_t *rc, uint16_t *p, int *symbol)
 {
-       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;
-       }
+       int ret = rc_is_bit_1(rc, p);
+       *symbol = *symbol * 2 + ret;
+       return ret;
 }
 
 /* Called once */
@@ -236,14 +220,11 @@ unpack_lzma_stream(int src_fd, int dst_fd)
        int lc, pb, lp;
        uint32_t pos_state_mask;
        uint32_t literal_pos_mask;
-       uint32_t pos;
        uint16_t *p;
-       uint16_t *prob;
-       uint16_t *prob_lit;
        int num_bits;
        int num_probs;
        rc_t *rc;
-       int i, mi;
+       int i;
        uint8_t *buffer;
        uint8_t previous_byte = 0;
        size_t buffer_pos = 0, global_pos = 0;
@@ -251,14 +232,17 @@ unpack_lzma_stream(int src_fd, int dst_fd)
        int state = 0;
        uint32_t rep0 = 1, rep1 = 1, rep2 = 1, rep3 = 1;
 
-       xread(src_fd, &header, sizeof(header));
+       if (full_read(src_fd, &header, sizeof(header)) != sizeof(header)
+        || header.pos >= (9 * 5 * 5)
+       ) {
+               bb_error_msg("bad lzma header");
+               return -1;
+       }
 
-       if (header.pos >= (9 * 5 * 5))
-               bb_error_msg_and_die("bad header");
-       mi = header.pos / 9;
+       i = header.pos / 9;
        lc = header.pos % 9;
-       pb = mi / 5;
-       lp = mi % 5;
+       pb = i / 5;
+       lp = i % 5;
        pos_state_mask = (1 << pb) - 1;
        literal_pos_mask = (1 << lp) - 1;
 
@@ -266,13 +250,13 @@ 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 = 1;
+               header.dict_size++;
 
        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_LIT_SIZE << (lc + lp));
+       num_probs += LZMA_LITERAL - LZMA_BASE_SIZE;
        for (i = 0; i < num_probs; i++)
                p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;
 
@@ -280,11 +264,13 @@ unpack_lzma_stream(int src_fd, int dst_fd)
 
        while (global_pos + buffer_pos < header.dst_size) {
                int pos_state = (buffer_pos + global_pos) & pos_state_mask;
+               uint16_t *prob = p + LZMA_IS_MATCH + (state << LZMA_NUM_POS_BITS_MAX) + pos_state;
+
+               if (!rc_is_bit_1(rc, prob)) {
+                       static const char next_state[LZMA_NUM_STATES] =
+                               { 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 4, 5 };
+                       int mi = 1;
 
-               prob = p + LZMA_IS_MATCH + (state << LZMA_NUM_POS_BITS_MAX) + pos_state;
-               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))
@@ -294,8 +280,8 @@ unpack_lzma_stream(int src_fd, int dst_fd)
 
                        if (state >= LZMA_NUM_LIT_STATES) {
                                int match_byte;
+                               uint32_t pos = buffer_pos - rep0;
 
-                               pos = buffer_pos - rep0;
                                while (pos >= header.dict_size)
                                        pos += header.dict_size;
                                match_byte = buffer[pos];
@@ -304,22 +290,16 @@ unpack_lzma_stream(int src_fd, int dst_fd)
 
                                        match_byte <<= 1;
                                        bit = match_byte & 0x100;
-                                       prob_lit = prob + 0x100 + bit + mi;
-                                       bit ^= (rc_get_bit(rc, prob_lit, &mi) << 8); /* 0x100 or 0 */
+                                       bit ^= (rc_get_bit(rc, prob + 0x100 + bit + mi, &mi) << 8); /* 0x100 or 0 */
                                        if (bit)
                                                break;
                                } while (mi < 0x100);
                        }
                        while (mi < 0x100) {
-                               prob_lit = prob + mi;
-                               rc_get_bit(rc, prob_lit, &mi);
+                               rc_get_bit(rc, prob + mi, &mi);
                        }
 
-                       state -= 3;
-                       if (state < 4-3)
-                               state = 0;
-                       if (state >= 10-3)
-                               state -= 6-3;
+                       state = next_state[state];
 
                        previous_byte = (uint8_t) mi;
 #if ENABLE_FEATURE_LZMA_FAST
@@ -338,59 +318,46 @@ unpack_lzma_stream(int src_fd, int dst_fd)
 #endif
                } else {
                        int offset;
-                       uint16_t *prob_len;
+                       uint16_t *prob2;
+#define prob_len prob2
 
-                       rc_update_bit_1(rc, prob);
-                       prob = p + LZMA_IS_REP + state;
-                       if (rc_is_bit_0(rc, prob)) {
-                               rc_update_bit_0(rc, prob);
+                       prob2 = p + LZMA_IS_REP + state;
+                       if (!rc_is_bit_1(rc, prob2)) {
                                rep3 = rep2;
                                rep2 = rep1;
                                rep1 = rep0;
                                state = state < LZMA_NUM_LIT_STATES ? 0 : 3;
-                               prob = p + LZMA_LEN_CODER;
+                               prob2 = p + LZMA_LEN_CODER;
                        } else {
-                               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
+                               prob2 += LZMA_IS_REP_G0 - LZMA_IS_REP;
+                               if (!rc_is_bit_1(rc, prob2)) {
+                                       prob2 = (p + LZMA_IS_REP_0_LONG
                                                + (state << LZMA_NUM_POS_BITS_MAX)
                                                + pos_state
                                        );
-                                       if (rc_is_bit_0(rc, prob)) {
-                                               rc_update_bit_0(rc, prob);
-
-                                               state = state < LZMA_NUM_LIT_STATES ? 9 : 11;
+                                       if (!rc_is_bit_1(rc, prob2)) {
 #if ENABLE_FEATURE_LZMA_FAST
-                                               pos = buffer_pos - rep0;
+                                               uint32_t pos = buffer_pos - rep0;
+                                               state = state < LZMA_NUM_LIT_STATES ? 9 : 11;
                                                while (pos >= header.dict_size)
                                                        pos += header.dict_size;
                                                previous_byte = buffer[pos];
                                                goto one_byte1;
 #else
+                                               state = state < LZMA_NUM_LIT_STATES ? 9 : 11;
                                                len = 1;
                                                goto string;
 #endif
-                                       } else {
-                                               rc_update_bit_1(rc, prob);
                                        }
                                } else {
                                        uint32_t distance;
 
-                                       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);
+                                       prob2 += LZMA_IS_REP_G1 - LZMA_IS_REP_G0;
+                                       distance = rep1;
+                                       if (rc_is_bit_1(rc, prob2)) {
+                                               prob2 += LZMA_IS_REP_G2 - LZMA_IS_REP_G1;
+                                               distance = rep2;
+                                               if (rc_is_bit_1(rc, prob2)) {
                                                        distance = rep3;
                                                        rep3 = rep2;
                                                }
@@ -400,31 +367,27 @@ unpack_lzma_stream(int src_fd, int dst_fd)
                                        rep0 = distance;
                                }
                                state = state < LZMA_NUM_LIT_STATES ? 8 : 11;
-                               prob = p + LZMA_REP_LEN_CODER;
+                               prob2 = p + LZMA_REP_LEN_CODER;
                        }
 
-                       prob_len = prob + LZMA_LEN_CHOICE;
-                       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));
+                       prob_len = prob2 + LZMA_LEN_CHOICE;
+                       num_bits = LZMA_LEN_NUM_LOW_BITS;
+                       if (!rc_is_bit_1(rc, prob_len)) {
+                               prob_len += LZMA_LEN_LOW - LZMA_LEN_CHOICE
+                                           + (pos_state << LZMA_LEN_NUM_LOW_BITS);
                                offset = 0;
-                               num_bits = LZMA_LEN_NUM_LOW_BITS;
                        } else {
-                               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));
+                               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);
                                        offset = 1 << LZMA_LEN_NUM_LOW_BITS;
-                                       num_bits = LZMA_LEN_NUM_MID_BITS;
+                                       num_bits += LZMA_LEN_NUM_MID_BITS - LZMA_LEN_NUM_LOW_BITS;
                                } else {
-                                       rc_update_bit_1(rc, prob_len);
-                                       prob_len = prob + LZMA_LEN_HIGH;
+                                       prob_len += LZMA_LEN_HIGH - LZMA_LEN_CHOICE_2;
                                        offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
                                                  + (1 << LZMA_LEN_NUM_MID_BITS));
-                                       num_bits = LZMA_LEN_NUM_HIGH_BITS;
+                                       num_bits += LZMA_LEN_NUM_HIGH_BITS - LZMA_LEN_NUM_LOW_BITS;
                                }
                        }
                        rc_bit_tree_decode(rc, prob_len, num_bits, &len);
@@ -432,37 +395,36 @@ unpack_lzma_stream(int src_fd, int dst_fd)
 
                        if (state < 4) {
                                int pos_slot;
+                               uint16_t *prob3;
 
                                state += LZMA_NUM_LIT_STATES;
-                               prob = p + LZMA_POS_SLOT +
+                               prob3 = p + LZMA_POS_SLOT +
                                       ((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);
+                               rc_bit_tree_decode(rc, prob3,
+                                       LZMA_NUM_POS_SLOT_BITS, &pos_slot);
+                               rep0 = pos_slot;
                                if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
-                                       num_bits = (pos_slot >> 1) - 1;
+                                       int i2, mi2, num_bits2 = (pos_slot >> 1) - 1;
                                        rep0 = 2 | (pos_slot & 1);
                                        if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
-                                               rep0 <<= num_bits;
-                                               prob = p + LZMA_SPEC_POS + rep0 - pos_slot - 1;
+                                               rep0 <<= num_bits2;
+                                               prob3 = p + LZMA_SPEC_POS + rep0 - pos_slot - 1;
                                        } else {
-                                               num_bits -= LZMA_NUM_ALIGN_BITS;
-                                               while (num_bits--)
+                                               for (; num_bits2 != LZMA_NUM_ALIGN_BITS; num_bits2--)
                                                        rep0 = (rep0 << 1) | rc_direct_bit(rc);
-                                               prob = p + LZMA_ALIGN;
                                                rep0 <<= LZMA_NUM_ALIGN_BITS;
-                                               num_bits = LZMA_NUM_ALIGN_BITS;
+                                               prob3 = p + LZMA_ALIGN;
                                        }
-                                       i = 1;
-                                       mi = 1;
-                                       while (num_bits--) {
-                                               if (rc_get_bit(rc, prob + mi, &mi))
-                                                       rep0 |= i;
-                                               i <<= 1;
+                                       i2 = 1;
+                                       mi2 = 1;
+                                       while (num_bits2--) {
+                                               if (rc_get_bit(rc, prob3 + mi2, &mi2))
+                                                       rep0 |= i2;
+                                               i2 <<= 1;
                                        }
-                               } else
-                                       rep0 = pos_slot;
+                               }
                                if (++rep0 == 0)
                                        break;
                        }
@@ -470,7 +432,7 @@ unpack_lzma_stream(int src_fd, int dst_fd)
                        len += LZMA_MATCH_MIN_LEN;
  IF_NOT_FEATURE_LZMA_FAST(string:)
                        do {
-                               pos = buffer_pos - rep0;
+                               uint32_t pos = buffer_pos - rep0;
                                while (pos >= header.dict_size)
                                        pos += header.dict_size;
                                previous_byte = buffer[pos];