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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include <u.h>
#include <libc.h>
#include "go.h"
enum {
WORDSIZE = sizeof(uint32),
WORDBITS = 32,
};
uintptr
bvsize(uintptr n)
{
return ((n + WORDBITS - 1) / WORDBITS) * WORDSIZE;
}
Bvec*
bvalloc(int32 n)
{
Bvec *bv;
uintptr nbytes;
if(n < 0)
fatal("bvalloc: initial size is negative\n");
nbytes = sizeof(Bvec) + bvsize(n);
bv = malloc(nbytes);
if(bv == nil)
fatal("bvalloc: malloc failed\n");
memset(bv, 0, nbytes);
bv->n = n;
return bv;
}
void
bvset(Bvec *bv, int32 i)
{
uint32 mask;
if(i < 0 || i >= bv->n)
fatal("bvset: index %d is out of bounds with length %d\n", i, bv->n);
mask = 1U << (i % WORDBITS);
bv->b[i / WORDBITS] |= mask;
}
void
bvres(Bvec *bv, int32 i)
{
uint32 mask;
if(i < 0 || i >= bv->n)
fatal("bvres: index %d is out of bounds with length %d\n", i, bv->n);
mask = ~(1 << (i % WORDBITS));
bv->b[i / WORDBITS] &= mask;
}
int
bvget(Bvec *bv, int32 i)
{
uint32 mask, word;
if(i < 0 || i >= bv->n)
fatal("bvget: index %d is out of bounds with length %d\n", i, bv->n);
mask = 1 << (i % WORDBITS);
word = bv->b[i / WORDBITS] & mask;
return word ? 1 : 0;
}
int
bvisempty(Bvec *bv)
{
int32 i;
for(i = 0; i < bv->n; i += WORDBITS)
if(bv->b[i / WORDBITS] != 0)
return 0;
return 1;
}
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