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This is similar to using the hashmap in hashmap.c, but with an easier-to-use API. In particular, custom entry comparisons no longer need to be written, and lookups can be done without constructing a temporary entry structure. This is implemented as a thin wrapper over the hashmap API. In particular, this means that there is an additional 4-byte overhead due to the fact that the first 4 bytes of the hash is redundantly stored. For now, I'm taking the simpler approach, but if need be, we can reimplement oidmap without affecting the callers significantly. oidset has been updated to use oidmap. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
47 lines
1.2 KiB
C
47 lines
1.2 KiB
C
#ifndef OIDSET_H
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#define OIDSET_H
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#include "oidmap.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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struct oidmap map;
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};
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#define OIDSET_INIT { OIDMAP_INIT }
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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 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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#endif /* OIDSET_H */
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