am: improve author-script error reporting
[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 sha1hash(obj->oid.hash) % 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 }