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authorGravatar Rob Landley <rob@landley.net>2006-03-09 17:51:25 +0000
committerGravatar Rob Landley <rob@landley.net>2006-03-09 17:51:25 +0000
commit49a5599ae95580b05535cb16467ffb0c2a20b66e (patch)
tree0bbbab7a9b19f6b5c57a4045ed8f79e0c7822d47 /archival
parent478a188e851ed6fbcd58189929ba4cfc30170aed (diff)
downloadbusybox-49a5599ae95580b05535cb16467ffb0c2a20b66e.tar.gz
busybox-49a5599ae95580b05535cb16467ffb0c2a20b66e.tar.bz2
Patch from Denis Vlasenko to make unlzma smaller.
Diffstat (limited to 'archival')
-rw-r--r--archival/libunarchive/rangecoder.h38
1 files changed, 29 insertions, 9 deletions
diff --git a/archival/libunarchive/rangecoder.h b/archival/libunarchive/rangecoder.h
index bb4159112..43f752257 100644
--- a/archival/libunarchive/rangecoder.h
+++ b/archival/libunarchive/rangecoder.h
@@ -56,7 +56,8 @@ typedef struct {
#define RC_MODEL_TOTAL_BITS 11
-static speed_inline void rc_read(rc_t * rc)
+/* Called twice: once at startup and once in rc_normalize() */
+static void rc_read(rc_t * rc)
{
rc->buffer_size = read(rc->fd, rc->buffer, rc->buffer_size);
if (rc->buffer_size <= 0)
@@ -65,6 +66,7 @@ static speed_inline void rc_read(rc_t * rc)
rc->buffer_end = rc->buffer + rc->buffer_size;
}
+/* Called once */
static always_inline void rc_init(rc_t * rc, int fd, int buffer_size)
{
int i;
@@ -84,35 +86,50 @@ static always_inline void rc_init(rc_t * rc, int fd, int buffer_size)
}
}
+/* Called once. TODO: bb_maybe_free() */
static always_inline void rc_free(rc_t * rc)
{
if (ENABLE_FEATURE_CLEAN_UP)
free(rc->buffer);
}
+/* 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)) {
- if (rc->ptr >= rc->buffer_end)
- rc_read(rc);
- rc->range <<= 8;
- rc->code = (rc->code << 8) | *rc->ptr++;
+ rc_do_normalize(rc);
}
}
-static speed_inline int rc_is_bit_0(rc_t * rc, uint16_t * p)
+/* Called 9 times */
+/* Why rc_is_bit_0_helper exists?
+ * Because we want to always expose (rc->code < rc->bound) to optimizer
+ */
+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);
- return rc->code < rc->bound;
+ 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;
@@ -120,7 +137,8 @@ static speed_inline void rc_update_bit_1(rc_t * rc, uint16_t * p)
*p -= *p >> RC_MOVE_BITS;
}
-static speed_inline int rc_get_bit(rc_t * rc, uint16_t * p, int *symbol)
+/* Called 4 times in unlzma loop */
+static 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);
@@ -133,6 +151,7 @@ static speed_inline int rc_get_bit(rc_t * rc, uint16_t * p, int *symbol)
}
}
+/* Called once */
static always_inline int rc_direct_bit(rc_t * rc)
{
rc_normalize(rc);
@@ -144,6 +163,7 @@ static always_inline int rc_direct_bit(rc_t * rc)
return 0;
}
+/* Called twice */
static speed_inline void
rc_bit_tree_decode(rc_t * rc, uint16_t * p, int num_levels, int *symbol)
{