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/*-
* Copyright (c) 2006 Verdens Gang AS
* Copyright (c) 2006-2010 Varnish Software AS
* All rights reserved.
*
* Author: Poul-Henning Kamp <phk@phk.freebsd.dk>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* Self-sizeing bitmap operations
*/
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
/**********************************************************************
* Generic bitmap functions
*/
#define VBITMAP_TYPE unsigned /* Our preferred wordsize */
#define VBITMAP_LUMP (1024) /* How many bits we alloc at a time */
#define VBITMAP_WORD (sizeof(VBITMAP_TYPE) * 8)
#define VBITMAP_IDX(n) ((n) / VBITMAP_WORD)
#define VBITMAP_BIT(n) (1U << ((n) % VBITMAP_WORD))
static inline unsigned
vbit_rndup(unsigned bit, unsigned to)
{
bit += to - 1;
bit -= (bit % to);
return (bit);
}
struct vbitmap {
unsigned flags;
#define VBITMAP_FL_MALLOC 1 /* struct vbitmap is malloced */
#define VBITMAP_FL_MALLOC_BITS (1<<1) /* bits space is malloced */
VBITMAP_TYPE *bits;
unsigned nbits;
};
static inline void
vbit_expand(struct vbitmap *vb, unsigned bit)
{
unsigned char *p;
bit = vbit_rndup(bit, VBITMAP_LUMP);
assert(bit > vb->nbits);
if (vb->flags & VBITMAP_FL_MALLOC_BITS) {
p = realloc(vb->bits, bit / 8);
assert(p != NULL);
} else {
p = malloc(bit / 8);
assert(p != NULL);
if (vb->nbits > 0)
memcpy(p, vb->bits, vb->nbits / 8);
}
memset(p + vb->nbits / 8, 0, (bit - vb->nbits) / 8);
vb->flags |= VBITMAP_FL_MALLOC_BITS;
vb->bits = (void*)p;
vb->nbits = bit;
}
#define VBITMAP_SZ(b) (sizeof(struct vbitmap) + \
vbit_rndup(b, VBITMAP_WORD))
/*
* init from some extent of memory (e.g. workspace) which the caller must
* manage. Returns a vbitmap with as many bits as fit into sz in VBITMAP_WORD
* chunks.
*
* use VBITMAP_SZ to calculate sz
*/
static inline struct vbitmap *
vbit_init(void *p, size_t sz)
{
struct vbitmap *vb;
if (sz < sizeof(*vb))
return NULL;
memset(p, 0, sz);
vb = p;
p = (char *)p + sizeof(*vb);
sz -= sizeof(*vb);
vb->nbits = (sz / VBITMAP_WORD) * VBITMAP_WORD;
if (vb->nbits)
vb->bits = p;
return (vb);
}
/* init using malloc */
static inline struct vbitmap *
vbit_new(unsigned initial)
{
struct vbitmap *vb;
vb = calloc(1, sizeof *vb);
assert(vb != NULL);
vb->flags |= VBITMAP_FL_MALLOC;
if (initial == 0)
initial = VBITMAP_LUMP;
vbit_expand(vb, initial);
return (vb);
}
static inline void
vbit_destroy(struct vbitmap *vb)
{
if (vb == NULL)
return;
if (vb->flags & VBITMAP_FL_MALLOC_BITS) {
free(vb->bits);
vb->bits = NULL;
vb->nbits = 0;
}
if (vb->flags & VBITMAP_FL_MALLOC)
free(vb);
}
static inline void
vbit_set(struct vbitmap *vb, unsigned bit)
{
if (bit >= vb->nbits)
vbit_expand(vb, bit + 1);
vb->bits[VBITMAP_IDX(bit)] |= VBITMAP_BIT(bit);
}
static inline void
vbit_clr(const struct vbitmap *vb, unsigned bit)
{
if (bit < vb->nbits)
vb->bits[VBITMAP_IDX(bit)] &= ~VBITMAP_BIT(bit);
}
static inline int
vbit_test(const struct vbitmap *vb, unsigned bit)
{
if (bit >= vb->nbits)
return (0);
return (vb->bits[VBITMAP_IDX(bit)] & VBITMAP_BIT(bit));
}
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