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Diffstat (limited to 'include/ocache.h')
| -rw-r--r-- | include/ocache.h | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/include/ocache.h b/include/ocache.h new file mode 100644 index 0000000..c596c27 --- /dev/null +++ b/include/ocache.h @@ -0,0 +1,133 @@ +/* ocache.h -- a minimal object caching implementation. */ + +/* Copyright (C) 2002 Free Software Foundation, Inc. + + This file is part of GNU Bash, the Bourne Again SHell. + + Bash is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Bash is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with Bash. If not, see <http://www.gnu.org/licenses/>. +*/ + +#if !defined (_OCACHE_H_) +#define _OCACHE_H_ 1 + +#ifndef PTR_T + +#if defined (__STDC__) +# define PTR_T void * +#else +# define PTR_T char * +#endif + +#endif /* PTR_T */ + +#define OC_MEMSET(memp, xch, nbytes) \ +do { \ + if ((nbytes) <= 32) { \ + register char * mzp = (char *)(memp); \ + unsigned long mctmp = (nbytes); \ + register long mcn; \ + if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp &= 7; } \ + switch (mctmp) { \ + case 0: for(;;) { *mzp++ = xch; \ + case 7: *mzp++ = xch; \ + case 6: *mzp++ = xch; \ + case 5: *mzp++ = xch; \ + case 4: *mzp++ = xch; \ + case 3: *mzp++ = xch; \ + case 2: *mzp++ = xch; \ + case 1: *mzp++ = xch; if(mcn <= 0) break; mcn--; } \ + } \ + } else \ + memset ((memp), (xch), (nbytes)); \ +} while(0) + +typedef struct objcache { + PTR_T data; + int cs; /* cache size, number of objects */ + int nc; /* number of cache entries */ +} sh_obj_cache_t; + +/* Create an object cache C of N pointers to OTYPE. */ +#define ocache_create(c, otype, n) \ + do { \ + (c).data = xmalloc((n) * sizeof (otype *)); \ + (c).cs = (n); \ + (c).nc = 0; \ + } while (0) + +/* Destroy an object cache C. */ +#define ocache_destroy(c) \ + do { \ + if ((c).data) \ + xfree ((c).data); \ + (c).data = 0; \ + (c).cs = (c).nc = 0; \ + } while (0) + +/* Free all cached items, which are pointers to OTYPE, in object cache C. */ +#define ocache_flush(c, otype) \ + do { \ + while ((c).nc > 0) \ + xfree (((otype **)((c).data))[--(c).nc]); \ + } while (0) + +/* + * Allocate a new item of type pointer to OTYPE, using data from object + * cache C if any cached items exist, otherwise calling xmalloc. Return + * the object in R. + */ +#define ocache_alloc(c, otype, r) \ + do { \ + if ((c).nc > 0) { \ + (r) = (otype *)((otype **)((c).data))[--(c).nc]; \ + } else \ + (r) = (otype *)xmalloc (sizeof (otype)); \ + } while (0) + +/* + * Free an item R of type pointer to OTYPE, adding to object cache C if + * there is room and calling xfree if the cache is full. If R is added + * to the object cache, the contents are scrambled. + */ +#define ocache_free(c, otype, r) \ + do { \ + if ((c).nc < (c).cs) { \ + OC_MEMSET ((r), 0xdf, sizeof(otype)); \ + ((otype **)((c).data))[(c).nc++] = (r); \ + } else \ + xfree (r); \ + } while (0) + +/* + * One may declare and use an object cache as (for instance): + * + * sh_obj_cache_t wdcache = {0, 0, 0}; + * sh_obj_cache_t wlcache = {0, 0, 0}; + * + * ocache_create(wdcache, WORD_DESC, 30); + * ocache_create(wlcache, WORD_LIST, 30); + * + * WORD_DESC *wd; + * ocache_alloc (wdcache, WORD_DESC, wd); + * + * WORD_LIST *wl; + * ocache_alloc (wlcache, WORD_LIST, wl); + * + * ocache_free(wdcache, WORD_DESC, wd); + * ocache_free(wlcache, WORD_LIST, wl); + * + * The use is almost arbitrary. + */ + +#endif /* _OCACHE_H */ |