git/reftable/basics.c
Han-Wen Nienhuys ef8a6c6268 reftable: utility functions
This commit provides basic utility classes for the reftable library.

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-08 10:45:48 -07:00

128 lines
2.1 KiB
C

/*
Copyright 2020 Google LLC
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file or at
https://developers.google.com/open-source/licenses/bsd
*/
#include "basics.h"
void put_be24(uint8_t *out, uint32_t i)
{
out[0] = (uint8_t)((i >> 16) & 0xff);
out[1] = (uint8_t)((i >> 8) & 0xff);
out[2] = (uint8_t)(i & 0xff);
}
uint32_t get_be24(uint8_t *in)
{
return (uint32_t)(in[0]) << 16 | (uint32_t)(in[1]) << 8 |
(uint32_t)(in[2]);
}
void put_be16(uint8_t *out, uint16_t i)
{
out[0] = (uint8_t)((i >> 8) & 0xff);
out[1] = (uint8_t)(i & 0xff);
}
int binsearch(size_t sz, int (*f)(size_t k, void *args), void *args)
{
size_t lo = 0;
size_t hi = sz;
/* Invariants:
*
* (hi == sz) || f(hi) == true
* (lo == 0 && f(0) == true) || fi(lo) == false
*/
while (hi - lo > 1) {
size_t mid = lo + (hi - lo) / 2;
if (f(mid, args))
hi = mid;
else
lo = mid;
}
if (lo)
return hi;
return f(0, args) ? 0 : 1;
}
void free_names(char **a)
{
char **p;
if (!a) {
return;
}
for (p = a; *p; p++) {
reftable_free(*p);
}
reftable_free(a);
}
int names_length(char **names)
{
char **p = names;
for (; *p; p++) {
/* empty */
}
return p - names;
}
void parse_names(char *buf, int size, char ***namesp)
{
char **names = NULL;
size_t names_cap = 0;
size_t names_len = 0;
char *p = buf;
char *end = buf + size;
while (p < end) {
char *next = strchr(p, '\n');
if (next && next < end) {
*next = 0;
} else {
next = end;
}
if (p < next) {
if (names_len == names_cap) {
names_cap = 2 * names_cap + 1;
names = reftable_realloc(
names, names_cap * sizeof(*names));
}
names[names_len++] = xstrdup(p);
}
p = next + 1;
}
names = reftable_realloc(names, (names_len + 1) * sizeof(*names));
names[names_len] = NULL;
*namesp = names;
}
int names_equal(char **a, char **b)
{
int i = 0;
for (; a[i] && b[i]; i++) {
if (strcmp(a[i], b[i])) {
return 0;
}
}
return a[i] == b[i];
}
int common_prefix_size(struct strbuf *a, struct strbuf *b)
{
int p = 0;
for (; p < a->len && p < b->len; p++) {
if (a->buf[p] != b->buf[p])
break;
}
return p;
}