X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/mLib/blobdiff_plain/0875b58fcccadd756e11487185c2ac1d3ed8ab4d..2a36652160047f489a62cc6eed23a9bfe0631b2f:/sub.h?ds=sidebyside diff --git a/sub.h b/sub.h index e7bd633..1b07703 100644 --- a/sub.h +++ b/sub.h @@ -1,41 +1,57 @@ /* -*-c-*- * - * $Id: sub.h,v 1.1 1998/06/17 23:44:42 mdw Exp $ + * $Id: sub.h,v 1.6 2000/06/17 10:35:51 mdw Exp $ * * Allocation of known-size blocks * * (c) 1998 Straylight/Edgeware */ -/*----- Licensing notice --------------------------------------------------* +/*----- Licensing notice --------------------------------------------------* * * This file is part of the mLib utilities library. * * mLib 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 2 of the License, or - * (at your option) any later version. - * + * it under the terms of the GNU Library General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or (at your option) any later version. + * * mLib 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 mLib; if not, write to the Free Software Foundation, - * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * GNU Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with mLib; if not, write to the Free + * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, + * MA 02111-1307, USA. */ /*----- Revision history --------------------------------------------------* * * $Log: sub.h,v $ - * Revision 1.1 1998/06/17 23:44:42 mdw - * Initial revision + * Revision 1.6 2000/06/17 10:35:51 mdw + * Major overhaul for arena support. + * + * Revision 1.5 1999/12/10 23:42:04 mdw + * Change header file guard names. + * + * Revision 1.4 1999/05/13 22:48:55 mdw + * Change `-ise' to `-ize' throughout. + * + * Revision 1.3 1999/05/06 19:51:35 mdw + * Reformatted the LGPL notice a little bit. + * + * Revision 1.2 1999/05/05 18:50:31 mdw + * Change licensing conditions to LGPL. + * + * Revision 1.1.1.1 1998/06/17 23:44:42 mdw + * Initial version of mLib * */ -#ifndef SUB_H -#define SUB_H +#ifndef MLIB_SUB_H +#define MLIB_SUB_H #ifdef __cplusplus extern "C" { @@ -45,27 +61,160 @@ #include -#ifndef ALLOC_H -# include "alloc.h" +#ifndef MLIB_ARENA_H +# include "arena.h" #endif +/*----- Configuration and tuning ------------------------------------------*/ + +/* --- The largest block I'll handle here --- * + * + * Anything larger will be handed on to the underlying @alloc@. + */ + +#define SUB_MAXBIN 256 + +/* --- Preferred chunk size --- * + * + * When a bin is empty, I'll allocate a large chunk of approximately this + * size and divvy it up into small bin-sized blocks. + */ + +#define SUB_CHUNK 4096 + +/*----- Other useful macros -----------------------------------------------*/ + +/* --- The granularity of bin buffers --- * + * + * All blocks allocated by the binner are a multiple of this size. I've + * chosen @void *@ because I need to store @void *@ things in here. + */ + +#define SUB_GRANULE sizeof(void *) + +/* --- Finding the right bin for a given size --- * + * + * This chooses the correct bin for an allocation. Input is the size of + * block wanted; result is the bin index. + */ + +#define SUB_BIN(x) (((x) + SUB_GRANULE - 1) / SUB_GRANULE) + +/* --- Convert a bin back to the block size --- * + * + * This gives the size of block contained in a given bin. + */ + +#define SUB_BINSZ(x) ((x) * SUB_GRANULE) + +/* --- Number of bins required --- */ + +#define SUB_BINS (SUB_MAXBIN / SUB_GRANULE + 1) + +/*----- Data structures ---------------------------------------------------*/ + +typedef struct subarena { + arena *a; + void *bin[SUB_BINS]; +} subarena; + +/*----- Global variables --------------------------------------------------*/ + +extern subarena sub_global; + /*----- Functions provided ------------------------------------------------*/ +/* --- @subarena_create@ --- * + * + * Arguments: @subarena *s@ = pointer to arena to initialize + * @arena *a@ = pointer to underlying arena block + * + * Returns: --- + * + * Use: Initialize a suballocation arena based on an underlying large + * blocks arena. + */ + +extern void subarena_create(subarena */*s*/, arena */*a*/); + +/* --- @subarena_destroy@ --- * + * + * Arguments: @subarena *s@ = pointer to arena to destroy + * + * Returns: --- + * + * Use: Destroys a suballocation arena, freeing all of the memory it + * contains back to the underlying large blocks arena. + */ + +extern void subarena_destroy(subarena */*s*/); + +/* --- @subarena_alloc@ --- * + * + * Arguments: @subarena *s@ = pointer to arena + * @size_t s@ = size of chunk wanted + * + * Returns: Pointer to a block at least as large as the one wanted. + * + * Use: Allocates a small block of memory from the given pool. The + * exception @EXC_NOMEM@ is raised if the underlying arena is + * full. + */ + +extern void *subarena_alloc(subarena */*s*/, size_t /*sz*/); + +/* --- @subarena_free@ --- * + * + * Arguments: @subarena *s@ = pointer to arena + * @void *p@ = address of block to free + * @size_t s@ = size of block + * + * Returns: --- + * + * Use: Frees a block allocated by @subarena_alloc@. + */ + +extern void subarena_free(subarena */*s*/, void */*p*/, size_t /*sz*/); + +/* --- @A_CREATE@ --- * + * + * Arguments: @subarena *s@ = pointer to arena + * @type@ = type of object required; must be passable to + * @sizeof@ + * + * Returns: Pointer to a block sufficiently big to hold an object of the + * named type. + * + * Use: Allocates a block of the required type. + */ + +#define A_CREATE(a, type) subarena_alloc((a), sizeof(type)) + +/* --- @A_DESTROY@ --- * + * + * Arguments: @subarena *s@ = pointer to arena + * @void *p@ = pointer to an object + * + * Returns: --- + * + * Use: Frees the thing pointed to by @p@. + */ + +#define A_DESTROY(a, p) subarena_free((a), (p), sizeof(*p)) + +/*----- Shortcuts for the global pool -------------------------------------*/ + /* --- @sub_alloc@ --- * * * Arguments: @size_t s@ = size of chunk wanted * * Returns: Pointer to a block at least as large as the one wanted. * - * Use: Allocates a small block of memory. If there is no more - * memory left, the exception @EXC_NOMEM@ is raised. + * Use: Allocates a small block of memory from the @sub_global@ pool. */ -#ifdef TRACK_ENABLE -# define sub_alloc(s) xmalloc(s) -#else -void *sub_alloc(size_t s); -#endif +extern void *sub_alloc(size_t /*sz*/); +#define sub_alloc(sz) subarena_alloc(&sub_global, (sz)) /* --- @sub_free@ --- * * @@ -77,11 +226,8 @@ void *sub_alloc(size_t s); * Use: Frees a block allocated by @sub_alloc@. */ -#ifdef TRACK_ENABLE -# define sub_free(p, s) free(p) -#else -void sub_free(void *p, size_t s); -#endif +extern void sub_free(void */*p*/, size_t /*sz*/); +#define sub_free(p, sz) subarena_free(&sub_global, (p), (sz)) /* --- @CREATE@ --- * * @@ -113,10 +259,11 @@ void sub_free(void *p, size_t s); * * Returns: --- * - * Use: Initialises the magic allocator. + * Use: Initializes the magic allocator. This is no longer + * necessary. */ -void sub_init(void); +extern void sub_init(void); /*----- That's all, folks -------------------------------------------------*/