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/*
* Copyright (C) the libgit2 contributors. All rights reserved.
*
* This file is part of libgit2, distributed under the GNU GPL v2 with
* a Linking Exception. For full terms see the included COPYING file.
*/
#ifndef INCLUDE_bitvec_h__
#define INCLUDE_bitvec_h__
#include "common.h"
/*
* This is a silly little fixed length bit vector type that will store
* vectors of 64 bits or less directly in the structure and allocate
* memory for vectors longer than 64 bits. You can use the two versions
* transparently through the API and avoid heap allocation completely when
* using a short bit vector as a result.
*/
typedef struct {
size_t length;
union {
uint64_t *words;
uint64_t bits;
} u;
} git_bitvec;
GIT_INLINE(int) git_bitvec_init(git_bitvec *bv, size_t capacity)
{
memset(bv, 0x0, sizeof(*bv));
if (capacity >= 64) {
bv->length = (capacity / 64) + 1;
bv->u.words = git__calloc(bv->length, sizeof(uint64_t));
if (!bv->u.words)
return -1;
}
return 0;
}
#define GIT_BITVEC_MASK(BIT) ((uint64_t)1 << (BIT % 64))
#define GIT_BITVEC_WORD(BV, BIT) (BV->length ? &BV->u.words[BIT / 64] : &BV->u.bits)
GIT_INLINE(void) git_bitvec_set(git_bitvec *bv, size_t bit, bool on)
{
uint64_t *word = GIT_BITVEC_WORD(bv, bit);
uint64_t mask = GIT_BITVEC_MASK(bit);
if (on)
*word |= mask;
else
*word &= ~mask;
}
GIT_INLINE(bool) git_bitvec_get(git_bitvec *bv, size_t bit)
{
uint64_t *word = GIT_BITVEC_WORD(bv, bit);
return (*word & GIT_BITVEC_MASK(bit)) != 0;
}
GIT_INLINE(void) git_bitvec_clear(git_bitvec *bv)
{
if (!bv->length)
bv->u.bits = 0;
else
memset(bv->u.words, 0x0, bv->length * sizeof(uint64_t));
}
GIT_INLINE(void) git_bitvec_free(git_bitvec *bv)
{
if (bv->length)
git__free(bv->u.words);
}
#endif
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