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git/decorate.c
Jeff King 54988bdad7 decorate: allow const objects to be decorated
We don't actually modify the struct object, so there is no
reason not to accept const versions (and this allows other
callsites, like the next patch, to use the decoration
machinery).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-08-20 13:30:49 -07:00

87 lines
1.8 KiB
C

/*
* decorate.c - decorate a git object with some arbitrary
* data.
*/
#include "cache.h"
#include "object.h"
#include "decorate.h"
static unsigned int hash_obj(const struct object *obj, unsigned int n)
{
unsigned int hash = *(unsigned int *)obj->sha1;
return hash % n;
}
static void *insert_decoration(struct decoration *n, const struct object *base, void *decoration)
{
int size = n->size;
struct object_decoration *hash = n->hash;
int j = hash_obj(base, size);
while (hash[j].base) {
if (hash[j].base == base) {
void *old = hash[j].decoration;
hash[j].decoration = decoration;
return old;
}
if (++j >= size)
j = 0;
}
hash[j].base = base;
hash[j].decoration = decoration;
n->nr++;
return NULL;
}
static void grow_decoration(struct decoration *n)
{
int i;
int old_size = n->size;
struct object_decoration *old_hash = n->hash;
n->size = (old_size + 1000) * 3 / 2;
n->hash = xcalloc(n->size, sizeof(struct object_decoration));
n->nr = 0;
for (i = 0; i < old_size; i++) {
const struct object *base = old_hash[i].base;
void *decoration = old_hash[i].decoration;
if (!base)
continue;
insert_decoration(n, base, decoration);
}
free(old_hash);
}
/* Add a decoration pointer, return any old one */
void *add_decoration(struct decoration *n, const struct object *obj,
void *decoration)
{
int nr = n->nr + 1;
if (nr > n->size * 2 / 3)
grow_decoration(n);
return insert_decoration(n, obj, decoration);
}
/* Lookup a decoration pointer */
void *lookup_decoration(struct decoration *n, const struct object *obj)
{
int j;
/* nothing to lookup */
if (!n->size)
return NULL;
j = hash_obj(obj, n->size);
for (;;) {
struct object_decoration *ref = n->hash + j;
if (ref->base == obj)
return ref->decoration;
if (!ref->base)
return NULL;
if (++j == n->size)
j = 0;
}
}