| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Resource pool handling |
| 4 | * |
| 5 | * (c) 2000 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of the mLib utilities library. |
| 11 | * |
| 12 | * mLib is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU Library General Public License as |
| 14 | * published by the Free Software Foundation; either version 2 of the |
| 15 | * License, or (at your option) any later version. |
| 16 | * |
| 17 | * mLib is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU Library General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU Library General Public |
| 23 | * License along with mLib; if not, write to the Free |
| 24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 25 | * MA 02111-1307, USA. |
| 26 | */ |
| 27 | |
| 28 | #ifndef MLIB_POOL_H |
| 29 | #define MLIB_POOL_H |
| 30 | |
| 31 | #ifdef __cplusplus |
| 32 | extern "C" { |
| 33 | #endif |
| 34 | |
| 35 | /*----- Header files ------------------------------------------------------*/ |
| 36 | |
| 37 | #include <stdio.h> |
| 38 | |
| 39 | #ifndef MLIB_ARENA_H |
| 40 | # include "arena.h" |
| 41 | #endif |
| 42 | |
| 43 | #ifndef MLIB_SUB_H |
| 44 | # include "sub.h" |
| 45 | #endif |
| 46 | |
| 47 | /*----- Data structures ---------------------------------------------------*/ |
| 48 | |
| 49 | #define POOL_CHUNKSZ 65536 |
| 50 | |
| 51 | typedef struct pool_chunk { |
| 52 | struct pool_chunk *next; /* Next memory chunk in the chain */ |
| 53 | char *p; /* Free area in this chunk */ |
| 54 | size_t left; /* Amount of memory left */ |
| 55 | } pool_chunk; |
| 56 | |
| 57 | typedef struct pool_resource { |
| 58 | struct pool_resource *next; /* Next resource in the chain */ |
| 59 | void (*destroy)(struct pool_resource */*r*/); /* Destruction function */ |
| 60 | } pool_resource; |
| 61 | |
| 62 | typedef struct pool { |
| 63 | arena a; /* The arena for allocating memory */ |
| 64 | pool_chunk *c; /* Pointer to memory chunk list */ |
| 65 | pool_resource *r; /* Pointer to resource list */ |
| 66 | arena *pa; /* Arena for real allocation */ |
| 67 | } pool; |
| 68 | |
| 69 | typedef struct pool_file { |
| 70 | pool_resource r; /* A pool resource record */ |
| 71 | FILE *fp; /* The actual file handle */ |
| 72 | } pool_file; |
| 73 | |
| 74 | /*----- Basic pool management ---------------------------------------------*/ |
| 75 | |
| 76 | /* --- @pool_alloc@ --- * |
| 77 | * |
| 78 | * Arguments: @pool *p@ = pool to allocate from |
| 79 | * @size_t sz@ = size of block wanted |
| 80 | * |
| 81 | * Returns: Pointer to the requested block. |
| 82 | * |
| 83 | * Use: Allocates memory from a resource pool. Memory is never freed |
| 84 | * from pools: it is released when the pool is destroyed. |
| 85 | */ |
| 86 | |
| 87 | extern void *pool_alloc(pool */*p*/, size_t /*sz*/); |
| 88 | |
| 89 | /* --- @pool_strdup@ --- * |
| 90 | * |
| 91 | * Arguments: @pool *p@ = pool to allocate from |
| 92 | * @const char *s@ = pointer to string |
| 93 | * |
| 94 | * Returns: A pointer to a copy of the string. |
| 95 | * |
| 96 | * Use: Allocates a copy of a string. |
| 97 | */ |
| 98 | |
| 99 | extern char *pool_strdup(pool */*p*/, const char */*s*/); |
| 100 | |
| 101 | /* --- @pool_create@ --- * |
| 102 | * |
| 103 | * Arguments: @arena *a@ = pointer to an arena to allocate memory from |
| 104 | * |
| 105 | * Returns: A newly created resource pool. |
| 106 | * |
| 107 | * Use: Creates a resource pool which is not a child of any other |
| 108 | * resource pool. |
| 109 | */ |
| 110 | |
| 111 | extern pool *pool_create(arena */*a*/); |
| 112 | |
| 113 | /* --- @pool_destroy@ --- * |
| 114 | * |
| 115 | * Arguments: @pool *p@ = pointer to pool to destroy |
| 116 | * |
| 117 | * Returns: --- |
| 118 | * |
| 119 | * Use: Destroys a pool, freeing all of the resources within it. If |
| 120 | * this is a root pool, its memory will be deallocated; if it's |
| 121 | * a subpool, it is emptied and can be used again. |
| 122 | */ |
| 123 | |
| 124 | extern void pool_destroy(pool */*p*/); |
| 125 | |
| 126 | /* --- @pool_sub@ --- * |
| 127 | * |
| 128 | * Arguments: @pool *p@ = pointer to parent pool |
| 129 | * |
| 130 | * Returns: A new child pool of the parent. |
| 131 | * |
| 132 | * Use: Creates a subpool. The subpool can either be destroyed on |
| 133 | * its own, or will be automatically destroyed at the same time |
| 134 | * as the parent. |
| 135 | */ |
| 136 | |
| 137 | extern pool *pool_sub(pool */*p*/); |
| 138 | |
| 139 | /* --- @pool_add@ --- * |
| 140 | * |
| 141 | * Arguments: @pool *p@ = pointer to pool to add the resource to |
| 142 | * @pool_resource *r@ = pointer to resource block |
| 143 | * @void (*dfn)(pool_resource *r)@ = destruction function |
| 144 | * |
| 145 | * Returns: --- |
| 146 | * |
| 147 | * Use: Adds a resource to a pool. |
| 148 | */ |
| 149 | |
| 150 | #define POOL_ADD(p, rr, dfn) do { \ |
| 151 | pool *_p = (p); \ |
| 152 | pool_resource *_r = (rr); \ |
| 153 | _r->next = _p->r; \ |
| 154 | _r->destroy = dfn; \ |
| 155 | _p->r = _r; \ |
| 156 | } while (0) |
| 157 | |
| 158 | extern void pool_add(pool */*p*/, pool_resource */*r*/, |
| 159 | void (*/*dfn*/)(pool_resource */*r*/)); |
| 160 | |
| 161 | /*----- Various simple resource types -------------------------------------*/ |
| 162 | |
| 163 | /* --- @pool_fopen@ --- * |
| 164 | * |
| 165 | * Arguments: @pool *p@ = pointer to a pool |
| 166 | * @const char *file@ = name of the file to open |
| 167 | * @const char *how@ = string specifying opening parameters |
| 168 | * |
| 169 | * Returns: A pointer to a pool resource containing an open file handle, |
| 170 | * or null if the file open filed. |
| 171 | * |
| 172 | * Use: Opens a file so that it will be freed again when a pool is |
| 173 | * destroyed. |
| 174 | */ |
| 175 | |
| 176 | extern pool_file *pool_fopen(pool */*p*/, |
| 177 | const char */*file*/, const char */*how*/); |
| 178 | |
| 179 | /* --- @pool_fclose@ --- * |
| 180 | * |
| 181 | * Arguments: @pool_file *pf@ = pointer to a file resource |
| 182 | * |
| 183 | * Returns: The response from the @fclose@ function. |
| 184 | * |
| 185 | * Use: Closes a file. It is not an error to close a file multiple |
| 186 | * times. |
| 187 | */ |
| 188 | |
| 189 | extern int pool_fclose(pool_file */*pf*/); |
| 190 | |
| 191 | /* --- @pool_subarena@ --- * |
| 192 | * |
| 193 | * Arguments: @pool *p@ = pointer to the pool |
| 194 | * |
| 195 | * Returns: A subarena built from the pool's memory allocator. |
| 196 | * |
| 197 | * Use: Creates a suballocation arena attached to a pool. The arena |
| 198 | * and all of its memory will be freed when the pool is |
| 199 | * destroyed. |
| 200 | */ |
| 201 | |
| 202 | extern subarena *pool_subarena(pool */*p*/); |
| 203 | |
| 204 | /*----- That's all, folks -------------------------------------------------*/ |
| 205 | |
| 206 | #ifdef __cplusplus |
| 207 | } |
| 208 | #endif |
| 209 | |
| 210 | #endif |