Merge branch 'dl/compat-cleanup'
[git/git.git] / decorate.c
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
9 static unsigned int hash_obj(const struct object *obj, unsigned int n)
10 {
11 return oidhash(&obj->oid) % n;
12 }
13
14 static void *insert_decoration(struct decoration *n, const struct object *base, void *decoration)
15 {
16 int size = n->size;
17 struct decoration_entry *entries = n->entries;
18 unsigned int j = hash_obj(base, size);
19
20 while (entries[j].base) {
21 if (entries[j].base == base) {
22 void *old = entries[j].decoration;
23 entries[j].decoration = decoration;
24 return old;
25 }
26 if (++j >= size)
27 j = 0;
28 }
29 entries[j].base = base;
30 entries[j].decoration = decoration;
31 n->nr++;
32 return NULL;
33 }
34
35 static void grow_decoration(struct decoration *n)
36 {
37 int i;
38 int old_size = n->size;
39 struct decoration_entry *old_entries = n->entries;
40
41 n->size = (old_size + 1000) * 3 / 2;
42 n->entries = xcalloc(n->size, sizeof(struct decoration_entry));
43 n->nr = 0;
44
45 for (i = 0; i < old_size; i++) {
46 const struct object *base = old_entries[i].base;
47 void *decoration = old_entries[i].decoration;
48
49 if (!decoration)
50 continue;
51 insert_decoration(n, base, decoration);
52 }
53 free(old_entries);
54 }
55
56 void *add_decoration(struct decoration *n, const struct object *obj,
57 void *decoration)
58 {
59 int nr = n->nr + 1;
60
61 if (nr > n->size * 2 / 3)
62 grow_decoration(n);
63 return insert_decoration(n, obj, decoration);
64 }
65
66 void *lookup_decoration(struct decoration *n, const struct object *obj)
67 {
68 unsigned int j;
69
70 /* nothing to lookup */
71 if (!n->size)
72 return NULL;
73 j = hash_obj(obj, n->size);
74 for (;;) {
75 struct decoration_entry *ref = n->entries + j;
76 if (ref->base == obj)
77 return ref->decoration;
78 if (!ref->base)
79 return NULL;
80 if (++j == n->size)
81 j = 0;
82 }
83 }