git/decorate.c

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/*
* 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;
}
}