emo/busybox
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Patch from Denis Vlasenko to make unlzma smaller.

Browse Source
This commit is contained in:
Rob Landley 2006-03-09 17:51:25 +00:00
parent 478a188e85
commit 49a5599ae9
1 changed files with 29 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
archival/libunarchive/rangecoder.h
View File

@ -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)
{