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Diffstat (limited to 'src/util/patcache.c')
| -rw-r--r-- | src/util/patcache.c | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/src/util/patcache.c b/src/util/patcache.c new file mode 100644 index 0000000..824255c --- /dev/null +++ b/src/util/patcache.c @@ -0,0 +1,224 @@ +/* $Xorg: patcache.c,v 1.4 2001/02/09 02:04:04 xorgcvs Exp $ */ + +/* + +Copyright 1991, 1998 The Open Group + +Permission to use, copy, modify, distribute, and sell this software and its +documentation for any purpose is hereby granted without fee, provided that +the above copyright notice appear in all copies and that both that +copyright notice and this permission notice appear in supporting +documentation. + +The above copyright notice and this permission notice shall be included in +all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN +AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN +CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + +Except as contained in this notice, the name of The Open Group shall not be +used in advertising or otherwise to promote the sale, use or other dealings +in this Software without prior written authorization from The Open Group. + +*/ + +/* + * Author: Keith Packard, MIT X Consortium + */ + +#include <fontmisc.h> +#include <fontstruct.h> + +/* + * Static sized hash table for looking up font name patterns + * + * LRU entries, reusing old entries + */ + +#define NBUCKETS 16 +#define NENTRIES 64 + +#define UNSET (NENTRIES+1) + +typedef unsigned char EntryPtr; + +typedef struct _FontPatternCacheEntry { + struct _FontPatternCacheEntry *next, **prev; + short patlen; + char *pattern; + int hash; + FontPtr pFont; /* associated font */ +} FontPatternCacheEntryRec, *FontPatternCacheEntryPtr; + +typedef struct _FontPatternCache { + FontPatternCacheEntryPtr buckets[NBUCKETS]; + FontPatternCacheEntryRec entries[NENTRIES]; + FontPatternCacheEntryPtr free; +} FontPatternCacheRec; + +/* Empty cache (for rehash) */ +void +EmptyFontPatternCache (cache) + FontPatternCachePtr cache; +{ + int i; + + for (i = 0; i < NBUCKETS; i++) + cache->buckets[i] = 0; + for (i = 0; i < NENTRIES; i++) + { + cache->entries[i].next = &cache->entries[i+1]; + cache->entries[i].prev = 0; + cache->entries[i].pFont = 0; + xfree (cache->entries[i].pattern); + cache->entries[i].pattern = 0; + cache->entries[i].patlen = 0; + } + cache->free = &cache->entries[0]; + cache->entries[NENTRIES - 1].next = 0; +} + +/* Create and initialize cache */ +FontPatternCachePtr +MakeFontPatternCache () +{ + FontPatternCachePtr cache; + int i; + cache = (FontPatternCachePtr) xalloc (sizeof *cache); + if (!cache) + return 0; + for (i = 0; i < NENTRIES; i++) { + cache->entries[i].patlen = 0; + cache->entries[i].pattern = 0; + cache->entries[i].pFont = 0; + } + EmptyFontPatternCache (cache); + return cache; +} + +/* toss cache */ +void +FreeFontPatternCache (cache) + FontPatternCachePtr cache; +{ + int i; + + for (i = 0; i < NENTRIES; i++) + xfree (cache->entries[i].pattern); + xfree (cache); +} + +/* compute id for string */ +static int +Hash (string, len) + char *string; + int len; +{ + int hash; + + hash = 0; + while (len--) + hash = (hash << 1) ^ *string++; + if (hash < 0) + hash = -hash; + return hash; +} + +/* add entry */ +void +CacheFontPattern (cache, pattern, patlen, pFont) + FontPatternCachePtr cache; + char *pattern; + int patlen; + FontPtr pFont; +{ + FontPatternCacheEntryPtr e; + char *newpat; + int i; + + newpat = (char *) xalloc (patlen); + if (!newpat) + return; + if (cache->free) + { + e = cache->free; + cache->free = e->next; + } + else + { + i = rand (); + if (i < 0) + i = -i; + i %= NENTRIES; + e = &cache->entries[i]; + if (e->next) + e->next->prev = e->prev; + *e->prev = e->next; + xfree (e->pattern); + } + /* set pattern */ + memcpy (newpat, pattern, patlen); + e->pattern = newpat; + e->patlen = patlen; + /* link to new hash chain */ + e->hash = Hash (pattern, patlen); + i = e->hash % NBUCKETS; + e->next = cache->buckets[i]; + if (e->next) + e->next->prev = &(e->next); + cache->buckets[i] = e; + e->prev = &(cache->buckets[i]); + e->pFont = pFont; +} + +/* find matching entry */ +FontPtr +FindCachedFontPattern (cache, pattern, patlen) + FontPatternCachePtr cache; + char *pattern; + int patlen; +{ + int hash; + int i; + FontPatternCacheEntryPtr e; + + hash = Hash (pattern, patlen); + i = hash % NBUCKETS; + for (e = cache->buckets[i]; e; e = e->next) + { + if (e->patlen == patlen && e->hash == hash && + !memcmp (e->pattern, pattern, patlen)) + { + return e->pFont; + } + } + return 0; +} + +void +RemoveCachedFontPattern (cache, pFont) + FontPatternCachePtr cache; + FontPtr pFont; +{ + FontPatternCacheEntryPtr e; + int i; + + for (i = 0; i < NENTRIES; i++) + { + if ((e = &cache->entries[i])->pFont == pFont) + { + e->pFont = 0; + if (e->next) + e->next->prev = e->prev; + *e->prev = e->next; + e->next = cache->free; + cache->free = e; + xfree (e->pattern); + e->pattern = 0; + } + } +} |