mirror of
https://github.com/git/git.git
synced 2024-11-05 08:47:56 +01:00
38fd0721d0
When a reference buffer is used multiple times then its index can be computed only once and reused multiple times. This patch adds an extra pointer to a pointer argument (from_index) to diff_delta() for this. If from_index is NULL then everything is like before. If from_index is non NULL and *from_index is NULL then the index is created and its location stored to *from_index. In this case the caller has the responsibility to free the memory pointed to by *from_index. If from_index and *from_index are non NULL then the index is reused as is. This currently saves about 10% of CPU time to repack the git archive. Signed-off-by: Nicolas Pitre <nico@cam.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
34 lines
903 B
C
34 lines
903 B
C
#ifndef DELTA_H
|
|
#define DELTA_H
|
|
|
|
/* handling of delta buffers */
|
|
extern void *diff_delta(void *from_buf, unsigned long from_size,
|
|
void *to_buf, unsigned long to_size,
|
|
unsigned long *delta_size, unsigned long max_size);
|
|
extern void *patch_delta(void *src_buf, unsigned long src_size,
|
|
void *delta_buf, unsigned long delta_size,
|
|
unsigned long *dst_size);
|
|
|
|
/* the smallest possible delta size is 4 bytes */
|
|
#define DELTA_SIZE_MIN 4
|
|
|
|
/*
|
|
* This must be called twice on the delta data buffer, first to get the
|
|
* expected reference buffer size, and again to get the result buffer size.
|
|
*/
|
|
static inline unsigned long get_delta_hdr_size(const unsigned char **datap)
|
|
{
|
|
const unsigned char *data = *datap;
|
|
unsigned char cmd;
|
|
unsigned long size = 0;
|
|
int i = 0;
|
|
do {
|
|
cmd = *data++;
|
|
size |= (cmd & ~0x80) << i;
|
|
i += 7;
|
|
} while (cmd & 0x80);
|
|
*datap = data;
|
|
return size;
|
|
}
|
|
|
|
#endif
|