| 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 | /*----- Header files ------------------------------------------------------*/ |
| 29 | |
| 30 | #include <string.h> |
| 31 | |
| 32 | #include "align.h" |
| 33 | #include "alloc.h" |
| 34 | #include "arena.h" |
| 35 | #include "pool.h" |
| 36 | |
| 37 | /*----- Main code ---------------------------------------------------------*/ |
| 38 | |
| 39 | /* --- @doalloc@ --- * |
| 40 | * |
| 41 | * Arguments: @arena *a@ = pointer to arena to allocate memory from |
| 42 | * @pool_chunk **cc@ = pointer to chunk list |
| 43 | * @size_t sz@ = size of memory wanted |
| 44 | * |
| 45 | * Returns: Pointer to the allocated block. |
| 46 | * |
| 47 | * Use: The basic allocator for resource pools. This is also used |
| 48 | * during pool creation, hence the slightly bizarre interface. |
| 49 | */ |
| 50 | |
| 51 | static void *doalloc(arena *a, pool_chunk **cc, size_t sz) |
| 52 | { |
| 53 | pool_chunk *c; |
| 54 | void *p; |
| 55 | size_t csz, ssz; |
| 56 | |
| 57 | /* --- See if there's enough space --- * |
| 58 | * |
| 59 | * The chunks are sorted by available space, so if there's not enough space |
| 60 | * in the first chunk there isn't enough space anywhere. |
| 61 | */ |
| 62 | |
| 63 | ALIGN(sz); |
| 64 | c = *cc; |
| 65 | if (c && c->left >= sz) { |
| 66 | p = c->p; |
| 67 | c->p += sz; |
| 68 | c->left -= sz; |
| 69 | *cc = c->next; |
| 70 | } |
| 71 | |
| 72 | /* --- Failed to find anything --- * |
| 73 | * |
| 74 | * I must allocate a new block from the arena, then. |
| 75 | */ |
| 76 | |
| 77 | else { |
| 78 | ssz = sizeof(pool_chunk); |
| 79 | ALIGN(ssz); |
| 80 | csz = (ssz + sz + POOL_CHUNKSZ - 1); csz -= csz % POOL_CHUNKSZ; |
| 81 | c = x_alloc(a, csz); |
| 82 | p = (char *)c + ssz; |
| 83 | c->p = (char *)p + sz; |
| 84 | c->left = csz - ssz - sz; |
| 85 | } |
| 86 | |
| 87 | /* --- Move this chunk in the list so that it's sorted --- */ |
| 88 | |
| 89 | while (*cc && (*cc)->left > c->left) |
| 90 | cc = &(*cc)->next; |
| 91 | c->next = *cc; |
| 92 | *cc = c; |
| 93 | |
| 94 | /* --- Done --- */ |
| 95 | |
| 96 | return (p); |
| 97 | } |
| 98 | |
| 99 | /* --- @pool_alloc@ --- * |
| 100 | * |
| 101 | * Arguments: @pool *p@ = pool to allocate from |
| 102 | * @size_t sz@ = size of block wanted |
| 103 | * |
| 104 | * Returns: Pointer to the requested block. |
| 105 | * |
| 106 | * Use: Allocates memory from a resource pool. Memory is never freed |
| 107 | * from pools: it is released when the pool is destroyed. |
| 108 | */ |
| 109 | |
| 110 | void *pool_alloc(pool *p, size_t sz) |
| 111 | { |
| 112 | return (doalloc(p->pa, &p->c, sz)); |
| 113 | } |
| 114 | |
| 115 | /* --- @pool_strdup@ --- * |
| 116 | * |
| 117 | * Arguments: @pool *p@ = pool to allocate from |
| 118 | * @const char *s@ = pointer to string |
| 119 | * |
| 120 | * Returns: A pointer to a copy of the string. |
| 121 | * |
| 122 | * Use: Allocates a copy of a string. |
| 123 | */ |
| 124 | |
| 125 | char *pool_strdup(pool *p, const char *s) |
| 126 | { |
| 127 | size_t sz = strlen(s) + 1; |
| 128 | char *pp = doalloc(p->pa, &p->c, sz); |
| 129 | memcpy(pp, s, sz); |
| 130 | return (pp); |
| 131 | } |
| 132 | |
| 133 | /* --- Arena operations --- */ |
| 134 | |
| 135 | static void *palloc(arena *a, size_t sz) |
| 136 | { |
| 137 | pool *p = (pool *)a; |
| 138 | return (doalloc(p->pa, &p->c, sz)); |
| 139 | } |
| 140 | |
| 141 | static void pfree(arena *a, void *p) { return; } /* Trivial */ |
| 142 | |
| 143 | static arena_ops pool_ops = { palloc, arena_fakerealloc, pfree, 0 }; |
| 144 | |
| 145 | /* --- @pool_init@ --- * |
| 146 | * |
| 147 | * Arguments: @pool *p@ = pointer to the pool structure to initialize |
| 148 | * @arena *a@ = pointer to an arena to allocate memory from |
| 149 | * |
| 150 | * Returns: --- |
| 151 | * |
| 152 | * Use: Initializes a chunk of memory as a resource pool which is not |
| 153 | * a child of any other resource pool. |
| 154 | */ |
| 155 | |
| 156 | void pool_init(pool *p, arena *a) |
| 157 | { |
| 158 | p->a.ops = &pool_ops; |
| 159 | p->c = 0; |
| 160 | p->r = 0; |
| 161 | p->pa = a; |
| 162 | } |
| 163 | |
| 164 | /* --- @pool_create@ --- * |
| 165 | * |
| 166 | * Arguments: @arena *a@ = pointer to an arena to allocate memory from |
| 167 | * |
| 168 | * Returns: A newly created resource pool. |
| 169 | * |
| 170 | * Use: Creates a resource pool which is not a child of any other |
| 171 | * resource pool. |
| 172 | */ |
| 173 | |
| 174 | pool *pool_create(arena *a) |
| 175 | { |
| 176 | pool_chunk *c = 0; |
| 177 | pool *p = doalloc(a, &c, sizeof(pool)); |
| 178 | pool_init(p, a); |
| 179 | p->c = c; |
| 180 | return (p); |
| 181 | } |
| 182 | |
| 183 | /* --- @pool_destroy@ --- * |
| 184 | * |
| 185 | * Arguments: @pool *p@ = pointer to pool to destroy |
| 186 | * |
| 187 | * Returns: --- |
| 188 | * |
| 189 | * Use: Destroys a pool, freeing all of the resources within it. If |
| 190 | * this is a pool created by @pool_create@, its memory will be |
| 191 | * deallocated; if it's a subpool or it was initialized by |
| 192 | * @pool_init@, it is emptied and can be used again. |
| 193 | */ |
| 194 | |
| 195 | void pool_destroy(pool *p) |
| 196 | { |
| 197 | pool_resource *r, *rr; |
| 198 | arena *a; |
| 199 | pool_chunk *c, *cc; |
| 200 | |
| 201 | /* --- Dispose of all of the resources --- */ |
| 202 | |
| 203 | r = p->r; |
| 204 | while (r) { |
| 205 | rr = r->next; |
| 206 | if (r->destroy) |
| 207 | r->destroy(r); |
| 208 | r = rr; |
| 209 | } |
| 210 | p->r = 0; |
| 211 | |
| 212 | /* --- Free all of the memory --- * |
| 213 | * |
| 214 | * Since root pools are allocated in their own memory, this will free the |
| 215 | * root pool block. Subpools are allocated in their parent's memory, so |
| 216 | * the pool block itself will be left around. |
| 217 | */ |
| 218 | |
| 219 | a = p->pa; |
| 220 | c = p->c; |
| 221 | p->c = 0; |
| 222 | while (c) { |
| 223 | cc = c->next; |
| 224 | x_free(a, c); |
| 225 | c = cc; |
| 226 | } |
| 227 | } |
| 228 | |
| 229 | /* --- @pool_add@ --- * |
| 230 | * |
| 231 | * Arguments: @pool *p@ = pointer to pool to add the resource to |
| 232 | * @pool_resource *r@ = pointer to resource block |
| 233 | * @void (*dfn)(pool_resource *r)@ = destruction function |
| 234 | * |
| 235 | * Returns: --- |
| 236 | * |
| 237 | * Use: Adds a resource to a pool. |
| 238 | */ |
| 239 | |
| 240 | void pool_add(pool *p, pool_resource *r, void (*dfn)(pool_resource *r)) |
| 241 | { |
| 242 | POOL_ADD(p, r, dfn); |
| 243 | } |
| 244 | |
| 245 | /* --- @pool_sub@ --- * |
| 246 | * |
| 247 | * Arguments: @pool *p@ = pointer to parent pool |
| 248 | * |
| 249 | * Returns: A new child pool of the parent. |
| 250 | * |
| 251 | * Use: Creates a subpool. The subpool can either be destroyed on |
| 252 | * its own, or will be automatically destroyed at the same time |
| 253 | * as the parent. |
| 254 | */ |
| 255 | |
| 256 | typedef struct subpool { |
| 257 | pool_resource r; |
| 258 | pool p; |
| 259 | } subpool; |
| 260 | |
| 261 | static void subpool_destroy(pool_resource *r) |
| 262 | { |
| 263 | subpool *p = (subpool *)r; |
| 264 | pool_destroy(&p->p); |
| 265 | } |
| 266 | |
| 267 | pool *pool_sub(pool *p) |
| 268 | { |
| 269 | subpool *pp = pool_alloc(p, sizeof(subpool)); |
| 270 | POOL_ADD(p, &pp->r, subpool_destroy); |
| 271 | pp->p.a.ops = &pool_ops; |
| 272 | pp->p.c = 0; |
| 273 | pp->p.r = 0; |
| 274 | pp->p.pa = p->pa; |
| 275 | return (&pp->p); |
| 276 | } |
| 277 | |
| 278 | /*----- That's all, folks -------------------------------------------------*/ |