ref: 11025d6f4a2c3c7e75010f85c2d3108e602270b7
dir: /sys/src/cmd/gs/src/gxbcache.c/
/* Copyright (C) 1995, 1996 Aladdin Enterprises. All rights reserved.
This software is provided AS-IS with no warranty, either express or
implied.
This software is distributed under license and may not be copied,
modified or distributed except as expressly authorized under the terms
of the license contained in the file LICENSE in this distribution.
For more information about licensing, please refer to
http://www.ghostscript.com/licensing/. For information on
commercial licensing, go to http://www.artifex.com/licensing/ or
contact Artifex Software, Inc., 101 Lucas Valley Road #110,
San Rafael, CA 94903, U.S.A., +1(415)492-9861.
*/
/* $Id: gxbcache.c,v 1.4 2002/02/21 22:24:52 giles Exp $ */
/* Bitmap cache implementation */
#include "memory_.h"
#include "gx.h"
#include "gsmdebug.h"
#include "gxbcache.h"
/* ------ Entire cache ------ */
/* Initialize a cache. The caller must allocate and initialize */
/* the first chunk. */
void
gx_bits_cache_init(gx_bits_cache * bc, gx_bits_cache_chunk * bck)
{
bck->next = bck;
bc->chunks = bck;
bc->cnext = 0;
bc->bsize = 0;
bc->csize = 0;
}
/* ------ Chunks ------ */
/* Initialize a chunk. The caller must allocate it and its data. */
void
gx_bits_cache_chunk_init(gx_bits_cache_chunk * bck, byte * data, uint size)
{
bck->next = 0;
bck->data = data;
bck->size = size;
bck->allocated = 0;
if (data != 0) {
gx_cached_bits_head *cbh = (gx_cached_bits_head *) data;
cbh->size = size;
cb_head_set_free(cbh);
}
}
/* ------ Individual entries ------ */
/* Attempt to allocate an entry. If successful, set *pcbh and return 0. */
/* If there isn't enough room, set *pcbh to an entry requiring freeing, */
/* or to 0 if we are at the end of the chunk, and return -1. */
int
gx_bits_cache_alloc(gx_bits_cache * bc, ulong lsize, gx_cached_bits_head ** pcbh)
{
#define ssize ((uint)lsize)
ulong lsize1 = lsize + sizeof(gx_cached_bits_head);
#define ssize1 ((uint)lsize1)
uint cnext = bc->cnext;
gx_bits_cache_chunk *bck = bc->chunks;
uint left = bck->size - cnext;
gx_cached_bits_head *cbh;
gx_cached_bits_head *cbh_next;
uint fsize = 0;
if (lsize1 > bck->size - cnext && lsize != left) { /* Not enough room to allocate in this chunk. */
*pcbh = 0;
return -1;
}
/* Look for and/or free enough space. */
cbh = cbh_next = (gx_cached_bits_head *) (bck->data + cnext);
while (fsize < ssize1 && fsize != ssize) {
if (!cb_head_is_free(cbh_next)) { /* Ask the caller to free the entry. */
if (fsize)
cbh->size = fsize;
*pcbh = cbh_next;
return -1;
}
fsize += cbh_next->size;
if_debug2('K', "[K]merging free bits 0x%lx(%u)\n",
(ulong) cbh_next, cbh_next->size);
cbh_next = (gx_cached_bits_head *) ((byte *) cbh + fsize);
}
if (fsize > ssize) { /* fsize >= ssize1 */
cbh_next = (gx_cached_bits_head *) ((byte *) cbh + ssize);
cbh_next->size = fsize - ssize;
cb_head_set_free(cbh_next);
if_debug2('K', "[K]shortening bits 0x%lx by %u (initial)\n",
(ulong) cbh, fsize - ssize);
}
gs_alloc_fill(cbh, gs_alloc_fill_block, ssize);
cbh->size = ssize;
bc->bsize += ssize;
bc->csize++;
bc->cnext += ssize;
bck->allocated += ssize;
*pcbh = cbh;
return 0;
#undef ssize
#undef ssize1
}
/* Shorten an entry by a given amount. */
void
gx_bits_cache_shorten(gx_bits_cache * bc, gx_cached_bits_head * cbh,
uint diff, gx_bits_cache_chunk * bck)
{
gx_cached_bits_head *next;
if ((byte *) cbh + cbh->size == bck->data + bc->cnext &&
bck == bc->chunks
)
bc->cnext -= diff;
bc->bsize -= diff;
bck->allocated -= diff;
cbh->size -= diff;
next = (gx_cached_bits_head *) ((byte *) cbh + cbh->size);
cb_head_set_free(next);
next->size = diff;
}
/* Free an entry. The caller is responsible for removing the entry */
/* from any other structures (like a hash table). */
void
gx_bits_cache_free(gx_bits_cache * bc, gx_cached_bits_head * cbh,
gx_bits_cache_chunk * bck)
{
uint size = cbh->size;
bc->csize--;
bc->bsize -= size;
bck->allocated -= size;
gs_alloc_fill(cbh, gs_alloc_fill_deleted, size);
cbh->size = size; /* gs_alloc_fill may have overwritten */
cb_head_set_free(cbh);
}