Files
git/hex.c
René Scharfe 63621bcbba hex: add and use strbuf_add_oid_hex()
Add a function for adding the full hexadecimal hash value of an object
ID to a strbuf.  It's thread-safe and slightly more efficient than using
strbuf_addstr() with oid_to_hex() because it doesn't have to determine
the length of the string or copy it from the intermediate static buffer.

Add and apply a semantic patch to use it throughout the code base.

I get a tiny speedup for git log showing a single hash per commit:

Benchmark 1: ./git_main log --format=%H
  Time (mean ± σ):      91.2 ms ±   0.7 ms    [User: 51.9 ms, System: 38.6 ms]
  Range (min … max):    89.8 ms …  92.6 ms    31 runs

Benchmark 2: ./git log --format=%H
  Time (mean ± σ):      90.5 ms ±   0.7 ms    [User: 51.0 ms, System: 38.8 ms]
  Range (min … max):    89.2 ms …  92.3 ms    32 runs

Summary
  ./git log --format=%H ran
    1.01 ± 0.01 times faster than ./git_main log --format=%H

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-05-14 15:59:25 +09:00

135 lines
3.2 KiB
C

#define USE_THE_REPOSITORY_VARIABLE
#include "git-compat-util.h"
#include "hash.h"
#include "hex.h"
#include "strbuf.h"
static int get_hash_hex_algop(const char *hex, unsigned char *hash,
const struct git_hash_algo *algop)
{
for (size_t i = 0; i < algop->rawsz; i++) {
int val = hex2chr(hex);
if (val < 0)
return -1;
*hash++ = val;
hex += 2;
}
return 0;
}
int get_hash_hex(const char *hex, unsigned char *sha1)
{
return get_hash_hex_algop(hex, sha1, the_hash_algo);
}
int get_oid_hex_algop(const char *hex, struct object_id *oid,
const struct git_hash_algo *algop)
{
int ret = get_hash_hex_algop(hex, oid->hash, algop);
if (!ret) {
oid_set_algo(oid, algop);
if (algop->rawsz != GIT_MAX_RAWSZ)
memset(oid->hash + algop->rawsz, 0,
GIT_MAX_RAWSZ - algop->rawsz);
}
return ret;
}
/*
* NOTE: This function relies on hash algorithms being in order from shortest
* length to longest length.
*/
int get_oid_hex_any(const char *hex, struct object_id *oid)
{
int i;
for (i = GIT_HASH_NALGOS - 1; i > 0; i--) {
if (!get_oid_hex_algop(hex, oid, &hash_algos[i]))
return i;
}
return GIT_HASH_UNKNOWN;
}
int get_oid_hex(const char *hex, struct object_id *oid)
{
return get_oid_hex_algop(hex, oid, the_hash_algo);
}
int parse_oid_hex_algop_impl(const char *hex, struct object_id *oid,
const char **end,
const struct git_hash_algo *algop)
{
int ret = get_oid_hex_algop(hex, oid, algop);
if (!ret)
*end = hex + algop->hexsz;
return ret;
}
int parse_oid_hex_any(const char *hex, struct object_id *oid, const char **end)
{
int ret = get_oid_hex_any(hex, oid);
if (ret)
*end = hex + hash_algos[ret].hexsz;
return ret;
}
int parse_oid_hex(const char *hex, struct object_id *oid, const char **end)
{
return parse_oid_hex_algop(hex, oid, end, the_hash_algo);
}
char *hash_to_hex_algop_r(char *buffer, const unsigned char *hash,
const struct git_hash_algo *algop)
{
static const char hex[] = "0123456789abcdef";
char *buf = buffer;
/*
* Our struct object_id has been memset to 0, so default to printing
* using the default hash.
*/
if (algop == &hash_algos[0])
algop = the_hash_algo;
for (size_t i = 0; i < algop->rawsz; i++) {
unsigned int val = *hash++;
*buf++ = hex[val >> 4];
*buf++ = hex[val & 0xf];
}
*buf = '\0';
return buffer;
}
char *oid_to_hex_r(char *buffer, const struct object_id *oid)
{
return hash_to_hex_algop_r(buffer, oid->hash, &hash_algos[oid->algo]);
}
char *hash_to_hex_algop(const unsigned char *hash, const struct git_hash_algo *algop)
{
static int bufno;
static char hexbuffer[4][GIT_MAX_HEXSZ + 1];
bufno = (bufno + 1) % ARRAY_SIZE(hexbuffer);
return hash_to_hex_algop_r(hexbuffer[bufno], hash, algop);
}
char *hash_to_hex(const unsigned char *hash)
{
return hash_to_hex_algop(hash, the_hash_algo);
}
char *oid_to_hex(const struct object_id *oid)
{
return hash_to_hex_algop(oid->hash, &hash_algos[oid->algo]);
}
void strbuf_add_oid_hex(struct strbuf *sb, const struct object_id *oid)
{
const struct git_hash_algo *algop = oid->algo ?
&hash_algos[oid->algo] : the_hash_algo;
strbuf_grow(sb, algop->hexsz);
hash_to_hex_algop_r(sb->buf + sb->len, oid->hash, algop);
strbuf_setlen(sb, sb->len + algop->hexsz);
}