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1 | #ifndef OIDSET_H | |
2 | #define OIDSET_H | |
3 | ||
4 | #include "hashmap.h" | |
5 | #include "khash.h" | |
6 | ||
7 | /** | |
8 | * This API is similar to sha1-array, in that it maintains a set of object ids | |
9 | * in a memory-efficient way. The major differences are: | |
10 | * | |
11 | * 1. It uses a hash, so we can do online duplicate removal, rather than | |
12 | * sort-and-uniq at the end. This can reduce memory footprint if you have | |
13 | * a large list of oids with many duplicates. | |
14 | * | |
15 | * 2. The per-unique-oid memory footprint is slightly higher due to hash | |
16 | * table overhead. | |
17 | */ | |
18 | ||
19 | static inline unsigned int oid_hash(struct object_id oid) | |
20 | { | |
21 | return sha1hash(oid.hash); | |
22 | } | |
23 | ||
24 | static inline int oid_equal(struct object_id a, struct object_id b) | |
25 | { | |
26 | return oideq(&a, &b); | |
27 | } | |
28 | ||
29 | KHASH_INIT(oid, struct object_id, int, 0, oid_hash, oid_equal) | |
30 | ||
31 | /** | |
32 | * A single oidset; should be zero-initialized (or use OIDSET_INIT). | |
33 | */ | |
34 | struct oidset { | |
35 | kh_oid_t set; | |
36 | }; | |
37 | ||
38 | #define OIDSET_INIT { { 0 } } | |
39 | ||
40 | ||
41 | /** | |
42 | * Initialize the oidset structure `set`. | |
43 | * | |
44 | * If `initial_size` is bigger than 0 then preallocate to allow inserting | |
45 | * the specified number of elements without further allocations. | |
46 | */ | |
47 | void oidset_init(struct oidset *set, size_t initial_size); | |
48 | ||
49 | /** | |
50 | * Returns true iff `set` contains `oid`. | |
51 | */ | |
52 | int oidset_contains(const struct oidset *set, const struct object_id *oid); | |
53 | ||
54 | /** | |
55 | * Insert the oid into the set; a copy is made, so "oid" does not need | |
56 | * to persist after this function is called. | |
57 | * | |
58 | * Returns 1 if the oid was already in the set, 0 otherwise. This can be used | |
59 | * to perform an efficient check-and-add. | |
60 | */ | |
61 | int oidset_insert(struct oidset *set, const struct object_id *oid); | |
62 | ||
63 | /** | |
64 | * Remove the oid from the set. | |
65 | * | |
66 | * Returns 1 if the oid was present in the set, 0 otherwise. | |
67 | */ | |
68 | int oidset_remove(struct oidset *set, const struct object_id *oid); | |
69 | ||
70 | /** | |
71 | * Remove all entries from the oidset, freeing any resources associated with | |
72 | * it. | |
73 | */ | |
74 | void oidset_clear(struct oidset *set); | |
75 | ||
76 | struct oidset_iter { | |
77 | kh_oid_t *set; | |
78 | khiter_t iter; | |
79 | }; | |
80 | ||
81 | static inline void oidset_iter_init(struct oidset *set, | |
82 | struct oidset_iter *iter) | |
83 | { | |
84 | iter->set = &set->set; | |
85 | iter->iter = kh_begin(iter->set); | |
86 | } | |
87 | ||
88 | static inline struct object_id *oidset_iter_next(struct oidset_iter *iter) | |
89 | { | |
90 | for (; iter->iter != kh_end(iter->set); iter->iter++) { | |
91 | if (kh_exist(iter->set, iter->iter)) | |
92 | return &kh_key(iter->set, iter->iter++); | |
93 | } | |
94 | return NULL; | |
95 | } | |
96 | ||
97 | static inline struct object_id *oidset_iter_first(struct oidset *set, | |
98 | struct oidset_iter *iter) | |
99 | { | |
100 | oidset_iter_init(set, iter); | |
101 | return oidset_iter_next(iter); | |
102 | } | |
103 | ||
104 | #endif /* OIDSET_H */ |