8fbb558af4
khash lets us define a hash as either a map or a set (i.e., with no "value" type). For the oid maps we define, "oid" is the set and "oid_map" is the map. As the bug in the previous commit shows, it's easy to pick the wrong one. So let's make the names more distinct: "oid_set" and "oid_map". An alternative naming scheme would be to actually name the type after the key/value types. So e.g., "oid" _would_ be the set, since it has no value type. And "oid_map" would become "oid_void" or similar (and "oid_pos" becomes "oid_int"). That's better in some ways: it's more regular, and a given map type can be more reasily reused in multiple contexts (e.g., something storing an "int" that isn't a "pos"). But it's also slightly less descriptive. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
93 lines
2.3 KiB
C
93 lines
2.3 KiB
C
#ifndef OIDSET_H
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#define OIDSET_H
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#include "hashmap.h"
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#include "khash.h"
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/**
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* This API is similar to sha1-array, in that it maintains a set of object ids
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* in a memory-efficient way. The major differences are:
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*
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* 1. It uses a hash, so we can do online duplicate removal, rather than
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* sort-and-uniq at the end. This can reduce memory footprint if you have
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* a large list of oids with many duplicates.
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*
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* 2. The per-unique-oid memory footprint is slightly higher due to hash
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* table overhead.
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*/
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/**
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* A single oidset; should be zero-initialized (or use OIDSET_INIT).
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*/
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struct oidset {
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kh_oid_set_t set;
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};
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#define OIDSET_INIT { { 0 } }
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/**
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* Initialize the oidset structure `set`.
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*
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* If `initial_size` is bigger than 0 then preallocate to allow inserting
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* the specified number of elements without further allocations.
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*/
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void oidset_init(struct oidset *set, size_t initial_size);
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/**
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* Returns true iff `set` contains `oid`.
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*/
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int oidset_contains(const struct oidset *set, const struct object_id *oid);
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/**
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* Insert the oid into the set; a copy is made, so "oid" does not need
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* to persist after this function is called.
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*
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* Returns 1 if the oid was already in the set, 0 otherwise. This can be used
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* to perform an efficient check-and-add.
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*/
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int oidset_insert(struct oidset *set, const struct object_id *oid);
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/**
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* Remove the oid from the set.
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*
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* Returns 1 if the oid was present in the set, 0 otherwise.
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*/
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int oidset_remove(struct oidset *set, const struct object_id *oid);
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/**
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* Remove all entries from the oidset, freeing any resources associated with
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* it.
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*/
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void oidset_clear(struct oidset *set);
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struct oidset_iter {
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kh_oid_set_t *set;
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khiter_t iter;
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};
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static inline void oidset_iter_init(struct oidset *set,
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struct oidset_iter *iter)
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{
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iter->set = &set->set;
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iter->iter = kh_begin(iter->set);
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}
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static inline struct object_id *oidset_iter_next(struct oidset_iter *iter)
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{
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for (; iter->iter != kh_end(iter->set); iter->iter++) {
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if (kh_exist(iter->set, iter->iter))
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return &kh_key(iter->set, iter->iter++);
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}
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return NULL;
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}
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static inline struct object_id *oidset_iter_first(struct oidset *set,
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struct oidset_iter *iter)
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{
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oidset_iter_init(set, iter);
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return oidset_iter_next(iter);
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}
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#endif /* OIDSET_H */
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