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 19static inline unsigned int oid_hash(struct object_id oid) 20{ 21 return sha1hash(oid.hash); 22} 23 24static inline int oid_equal(struct object_id a, struct object_id b) 25{ 26 return oideq(&a, &b); 27} 28 29KHASH_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 */ 34struct 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 */ 47void oidset_init(struct oidset *set, size_t initial_size); 48 49/** 50 * Returns true iff `set` contains `oid`. 51 */ 52int 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 */ 61int 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 */ 68int 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 */ 74void oidset_clear(struct oidset *set); 75 76struct oidset_iter { 77 kh_oid_t *set; 78 khiter_t iter; 79}; 80 81static 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 88static 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 97static 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 */