Merge commit 'bg/alshopov/master'
[git] / pack-objects.c
1 #include "cache.h"
2 #include "object.h"
3 #include "pack.h"
4 #include "pack-objects.h"
5
6 static uint32_t locate_object_entry_hash(struct packing_data *pdata,
7                                          const unsigned char *sha1,
8                                          int *found)
9 {
10         uint32_t i, mask = (pdata->index_size - 1);
11
12         i = sha1hash(sha1) & mask;
13
14         while (pdata->index[i] > 0) {
15                 uint32_t pos = pdata->index[i] - 1;
16
17                 if (!hashcmp(sha1, pdata->objects[pos].idx.sha1)) {
18                         *found = 1;
19                         return i;
20                 }
21
22                 i = (i + 1) & mask;
23         }
24
25         *found = 0;
26         return i;
27 }
28
29 static inline uint32_t closest_pow2(uint32_t v)
30 {
31         v = v - 1;
32         v |= v >> 1;
33         v |= v >> 2;
34         v |= v >> 4;
35         v |= v >> 8;
36         v |= v >> 16;
37         return v + 1;
38 }
39
40 static void rehash_objects(struct packing_data *pdata)
41 {
42         uint32_t i;
43         struct object_entry *entry;
44
45         pdata->index_size = closest_pow2(pdata->nr_objects * 3);
46         if (pdata->index_size < 1024)
47                 pdata->index_size = 1024;
48
49         free(pdata->index);
50         pdata->index = xcalloc(pdata->index_size, sizeof(*pdata->index));
51
52         entry = pdata->objects;
53
54         for (i = 0; i < pdata->nr_objects; i++) {
55                 int found;
56                 uint32_t ix = locate_object_entry_hash(pdata, entry->idx.sha1, &found);
57
58                 if (found)
59                         die("BUG: Duplicate object in hash");
60
61                 pdata->index[ix] = i + 1;
62                 entry++;
63         }
64 }
65
66 struct object_entry *packlist_find(struct packing_data *pdata,
67                                    const unsigned char *sha1,
68                                    uint32_t *index_pos)
69 {
70         uint32_t i;
71         int found;
72
73         if (!pdata->index_size)
74                 return NULL;
75
76         i = locate_object_entry_hash(pdata, sha1, &found);
77
78         if (index_pos)
79                 *index_pos = i;
80
81         if (!found)
82                 return NULL;
83
84         return &pdata->objects[pdata->index[i] - 1];
85 }
86
87 struct object_entry *packlist_alloc(struct packing_data *pdata,
88                                     const unsigned char *sha1,
89                                     uint32_t index_pos)
90 {
91         struct object_entry *new_entry;
92
93         if (pdata->nr_objects >= pdata->nr_alloc) {
94                 pdata->nr_alloc = (pdata->nr_alloc  + 1024) * 3 / 2;
95                 pdata->objects = xrealloc(pdata->objects,
96                                           pdata->nr_alloc * sizeof(*new_entry));
97         }
98
99         new_entry = pdata->objects + pdata->nr_objects++;
100
101         memset(new_entry, 0, sizeof(*new_entry));
102         hashcpy(new_entry->idx.sha1, sha1);
103
104         if (pdata->index_size * 3 <= pdata->nr_objects * 4)
105                 rehash_objects(pdata);
106         else
107                 pdata->index[index_pos] = pdata->nr_objects;
108
109         return new_entry;
110 }