/*
 * 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