Andrew's git - gitweb.git/blob

   1/*
   2 * decorate.c - decorate a git object with some arbitrary
   3 * data.
   4 */
   5#include "cache.h"
   6#include "object.h"
   7#include "decorate.h"
   8
   9static unsigned int hash_obj(struct object *obj, unsigned int n)
  10{
  11        unsigned int hash = *(unsigned int *)obj->sha1;
  12        return hash % n;
  13}
  14
  15static void *insert_decoration(struct decoration *n, struct object *base, void *decoration)
  16{
  17        int size = n->size;
  18        struct object_decoration *hash = n->hash;
  19        int j = hash_obj(base, size);
  20
  21        while (hash[j].base) {
  22                if (hash[j].base == base) {
  23                        void *old = hash[j].decoration;
  24                        hash[j].decoration = decoration;
  25                        return old;
  26                }
  27                if (++j >= size)
  28                        j = 0;
  29        }
  30        hash[j].base = base;
  31        hash[j].decoration = decoration;
  32        n->nr++;
  33        return NULL;
  34}
  35
  36static void grow_decoration(struct decoration *n)
  37{
  38        int i;
  39        int old_size = n->size;
  40        struct object_decoration *old_hash = n->hash;
  41
  42        n->size = (old_size + 1000) * 3 / 2;
  43        n->hash = xcalloc(n->size, sizeof(struct object_decoration));
  44        n->nr = 0;
  45
  46        for (i = 0; i < old_size; i++) {
  47                struct object *base = old_hash[i].base;
  48                void *decoration = old_hash[i].decoration;
  49
  50                if (!base)
  51                        continue;
  52                insert_decoration(n, base, decoration);
  53        }
  54        free(old_hash);
  55}
  56
  57/* Add a decoration pointer, return any old one */
  58void *add_decoration(struct decoration *n, struct object *obj, void *decoration)
  59{
  60        int nr = n->nr + 1;
  61
  62        if (nr > n->size * 2 / 3)
  63                grow_decoration(n);
  64        return insert_decoration(n, obj, decoration);
  65}
  66
  67/* Lookup a decoration pointer */
  68void *lookup_decoration(struct decoration *n, struct object *obj)
  69{
  70        int j;
  71
  72        /* nothing to lookup */
  73        if (!n->size)
  74                return NULL;
  75        j = hash_obj(obj, n->size);
  76        for (;;) {
  77                struct object_decoration *ref = n->hash + j;
  78                if (ref->base == obj)
  79                        return ref->decoration;
  80                if (!ref->base)
  81                        return NULL;
  82                if (++j == n->size)
  83                        j = 0;
  84        }
  85}