| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: mparena.c,v 1.7 2004/04/08 01:36:15 mdw Exp $ |
| 4 | * |
| 5 | * Allocation and freeing of MP buffers |
| 6 | * |
| 7 | * (c) 1999 Straylight/Edgeware |
| 8 | */ |
| 9 | |
| 10 | /*----- Licensing notice --------------------------------------------------* |
| 11 | * |
| 12 | * This file is part of Catacomb. |
| 13 | * |
| 14 | * Catacomb is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU Library General Public License as |
| 16 | * published by the Free Software Foundation; either version 2 of the |
| 17 | * License, or (at your option) any later version. |
| 18 | * |
| 19 | * Catacomb is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU Library General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU Library General Public |
| 25 | * License along with Catacomb; if not, write to the Free |
| 26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 27 | * MA 02111-1307, USA. |
| 28 | */ |
| 29 | |
| 30 | /*----- Header files ------------------------------------------------------*/ |
| 31 | |
| 32 | #include <stdio.h> |
| 33 | #include <stdlib.h> |
| 34 | #include <string.h> |
| 35 | |
| 36 | #include <mLib/arena.h> |
| 37 | #include <mLib/exc.h> |
| 38 | #include <mLib/sub.h> |
| 39 | |
| 40 | #include "mparena.h" |
| 41 | |
| 42 | /*----- Tweakables --------------------------------------------------------*/ |
| 43 | |
| 44 | /* --- @MPARENA_TRIVIAL@ --- * |
| 45 | * |
| 46 | * Make the allocator a passthrough. It immediately calls the underlying |
| 47 | * allocation functions rather than attempting to keep track of blocks |
| 48 | * itself. |
| 49 | */ |
| 50 | |
| 51 | /* #define MPARENA_TRIVIAL */ |
| 52 | |
| 53 | /* --- @MPARENA_DEBUG@ --- * |
| 54 | * |
| 55 | * The name of an output trace file to which logging information about the |
| 56 | * state of arena trees should be written. If unset, no logging is done. |
| 57 | */ |
| 58 | |
| 59 | /* #define MPARENA_DEBUG "mparena.out" */ |
| 60 | |
| 61 | /*----- Static variables --------------------------------------------------*/ |
| 62 | |
| 63 | #ifdef MPARENA_DEBUG |
| 64 | static FILE *debugfp = 0; |
| 65 | |
| 66 | # define MPARENA_OPENFILE do { \ |
| 67 | if (!debugfp) { \ |
| 68 | if ((debugfp = fopen(MPARENA_DEBUG, "w")) == 0) { \ |
| 69 | fprintf(stderr, "couldn't open debug output file\n"); \ |
| 70 | exit(EXIT_FAILURE); \ |
| 71 | } \ |
| 72 | } \ |
| 73 | } while (0) |
| 74 | |
| 75 | #endif |
| 76 | |
| 77 | /*----- Standard arenas ---------------------------------------------------*/ |
| 78 | |
| 79 | mparena mparena_global = MPARENA_INIT; |
| 80 | mparena mparena_secure = MPARENA_INIT; |
| 81 | |
| 82 | /*----- Main code ---------------------------------------------------------*/ |
| 83 | |
| 84 | /* --- @tdump@ --- * |
| 85 | * |
| 86 | * Arguments: @mparena_node *n@ = pointer to tree node to dump |
| 87 | * |
| 88 | * Returns: --- |
| 89 | * |
| 90 | * Use: Recursively dumps out the allocation tree. |
| 91 | */ |
| 92 | |
| 93 | #ifdef MPARENA_DEBUG |
| 94 | |
| 95 | static void tdump(mparena_node *n) |
| 96 | { |
| 97 | if (!n) |
| 98 | putc('*', debugfp); |
| 99 | else { |
| 100 | putc('(', debugfp); |
| 101 | tdump(n->left); |
| 102 | fprintf(debugfp, ", %u, ", n->v[0]); |
| 103 | tdump(n->right); |
| 104 | putc(')', debugfp); |
| 105 | } |
| 106 | } |
| 107 | |
| 108 | #endif |
| 109 | |
| 110 | /* --- @mparena_create@ --- * |
| 111 | * |
| 112 | * Arguments: @mparena *a@ = pointer to arena block |
| 113 | * |
| 114 | * Returns: --- |
| 115 | * |
| 116 | * Use: Initializes an MP arena so that blocks can be allocated from |
| 117 | * it. |
| 118 | */ |
| 119 | |
| 120 | void mparena_create(mparena *a) |
| 121 | { |
| 122 | a->root = 0; |
| 123 | a->n = 0; |
| 124 | a->a = &arena_stdlib; |
| 125 | } |
| 126 | |
| 127 | /* --- @mparena_setarena@ --- * |
| 128 | * |
| 129 | * Arguments: @mparena *a@ = pointer to MP arena block |
| 130 | * @arena *aa@ = pointer to arena |
| 131 | * |
| 132 | * Returns: --- |
| 133 | * |
| 134 | * Use: Sets the underlying arena for an MP arena. |
| 135 | */ |
| 136 | |
| 137 | extern void mparena_setarena(mparena *a, arena *aa) { a->a = aa; } |
| 138 | |
| 139 | /* --- @mparena_destroy@ --- * |
| 140 | * |
| 141 | * Arguments: @mparena *a@ = pointer to arena block |
| 142 | * |
| 143 | * Returns: --- |
| 144 | * |
| 145 | * Use: Frees an MP arena, and all the vectors held within it. The |
| 146 | * blocks which are currently allocated can be freed into some |
| 147 | * other arena. |
| 148 | */ |
| 149 | |
| 150 | static void tfree(mparena *a, mparena_node *n) |
| 151 | { |
| 152 | A_FREE(a->a, n->v); |
| 153 | if (n->left) |
| 154 | tfree(a, n->left); |
| 155 | if (n->right) |
| 156 | tfree(a, n->right); |
| 157 | DESTROY(n); |
| 158 | } |
| 159 | |
| 160 | void mparena_destroy(mparena *a) |
| 161 | { |
| 162 | tfree(a, a->root); |
| 163 | a->root = 0; |
| 164 | } |
| 165 | |
| 166 | /* --- @mparena_count@ --- * |
| 167 | * |
| 168 | * Arguments: @mparena *a@ = pointer to arena block |
| 169 | * |
| 170 | * Returns: Number of allocated blocks from this arena. |
| 171 | * |
| 172 | * Use: Reports the number of blocks allocated from the arena and not |
| 173 | * yet freed. |
| 174 | */ |
| 175 | |
| 176 | unsigned mparena_count(mparena *a) |
| 177 | { |
| 178 | return (a->n); |
| 179 | } |
| 180 | |
| 181 | /* --- @mpalloc@ --- * |
| 182 | * |
| 183 | * Arguments: @mparena *a@ = pointer to arena block |
| 184 | * @size_t sz@ = number of digits required |
| 185 | * |
| 186 | * Returns: Pointer to a suitably sized block. |
| 187 | * |
| 188 | * Use: Allocates a lump of data suitable for use as an array of MP |
| 189 | * digits. |
| 190 | */ |
| 191 | |
| 192 | #ifdef MPARENA_TRIVIAL |
| 193 | |
| 194 | mpw *mpalloc(mparena *a, size_t sz) |
| 195 | { |
| 196 | mpw *v; |
| 197 | if (!sz) return (0); |
| 198 | a->n++; |
| 199 | v = A_ALLOC(a->a, MPWS(sz)); |
| 200 | if (!v) |
| 201 | THROW(EXC_NOMEM); |
| 202 | return (v); |
| 203 | } |
| 204 | |
| 205 | #else |
| 206 | |
| 207 | mpw *mpalloc(mparena *a, size_t sz) |
| 208 | { |
| 209 | mparena_node **nn, *n; |
| 210 | mpw *v; |
| 211 | |
| 212 | nn = &a->root; |
| 213 | |
| 214 | #ifdef MPARENA_DEBUG |
| 215 | MPARENA_OPENFILE; |
| 216 | fprintf(debugfp, "alloc %u\n before: ", sz); |
| 217 | tdump(a->root); putc('\n', debugfp); |
| 218 | #endif |
| 219 | |
| 220 | /* --- First, find a block which is big enough --- */ |
| 221 | |
| 222 | again: |
| 223 | n = *nn; |
| 224 | if (!n) { |
| 225 | #ifdef MPARENA_DEBUG |
| 226 | fputs(" failed\n", debugfp); |
| 227 | #endif |
| 228 | if ((v = A_ALLOC(a->a, MPWS(sz + 1))) == 0) |
| 229 | THROW(EXC_NOMEM); |
| 230 | v[0] = sz; |
| 231 | a->n++; |
| 232 | return (v + 1); |
| 233 | } |
| 234 | if (n->v[0] < sz) { |
| 235 | nn = &n->right; |
| 236 | goto again; |
| 237 | } |
| 238 | |
| 239 | /* --- Now try to find a smaller block which is suitable --- */ |
| 240 | |
| 241 | while (n->left && n->left->v[0] >= sz) { |
| 242 | nn = &n->left; |
| 243 | n = *nn; |
| 244 | } |
| 245 | |
| 246 | /* --- If the block we've got is still too large, start digging --- */ |
| 247 | |
| 248 | if (n->v[0] > sz * 2) { |
| 249 | nn = &n->left; |
| 250 | goto again; |
| 251 | } |
| 252 | |
| 253 | /* --- I've now found a suitable block --- */ |
| 254 | |
| 255 | v = n->v; |
| 256 | |
| 257 | /* --- Remove this node from the tree --- */ |
| 258 | |
| 259 | if (!n->left) |
| 260 | *nn = n->right; |
| 261 | else if (!n->right) |
| 262 | *nn = n->left; |
| 263 | else { |
| 264 | mparena_node *left = n->left; |
| 265 | mparena_node *p = *nn = n->right; |
| 266 | while (p->left) |
| 267 | p = p->left; |
| 268 | p->left = left; |
| 269 | } |
| 270 | |
| 271 | #ifdef MPARENA_DEBUG |
| 272 | fputs(" after: ", debugfp); |
| 273 | tdump(a->root); putc('\n', debugfp); |
| 274 | #endif |
| 275 | |
| 276 | /* --- Get rid of this node now --- */ |
| 277 | |
| 278 | DESTROY(n); |
| 279 | a->n++; |
| 280 | return (v + 1); |
| 281 | } |
| 282 | |
| 283 | #endif |
| 284 | |
| 285 | /* --- @mpfree@ --- * |
| 286 | * |
| 287 | * Arguments: @mparena *a@ = pointer to arena block |
| 288 | * @mpw *v@ = pointer to allocated vector |
| 289 | * |
| 290 | * Returns: --- |
| 291 | * |
| 292 | * Use: Returns an MP vector to an arena. |
| 293 | */ |
| 294 | |
| 295 | #ifdef MPARENA_TRIVIAL |
| 296 | |
| 297 | void mpfree(mparena *a, mpw *v) |
| 298 | { |
| 299 | if (!v) return; |
| 300 | a->n--; |
| 301 | A_FREE(a->a, v); |
| 302 | } |
| 303 | |
| 304 | #else |
| 305 | |
| 306 | void mpfree(mparena *a, mpw *v) |
| 307 | { |
| 308 | mparena_node **nn, *n; |
| 309 | size_t sz = *--v; |
| 310 | |
| 311 | #ifdef MPARENA_DEBUG |
| 312 | MPARENA_OPENFILE; |
| 313 | fprintf(debugfp, "free %u\n before: ", sz); |
| 314 | tdump(a->root); putc('\n', debugfp); |
| 315 | #endif |
| 316 | |
| 317 | nn = &a->root; |
| 318 | while (*nn) { |
| 319 | n = *nn; |
| 320 | if (n->v[0] > sz) |
| 321 | nn = &n->left; |
| 322 | else |
| 323 | nn = &n->right; |
| 324 | } |
| 325 | |
| 326 | n = CREATE(mparena_node); |
| 327 | n->left = n->right = 0; |
| 328 | n->v = v; |
| 329 | *nn = n; |
| 330 | a->n--; |
| 331 | |
| 332 | #ifdef MPARENA_DEBUG |
| 333 | fputs(" after: ", debugfp); |
| 334 | tdump(a->root); putc('\n', debugfp); |
| 335 | #endif |
| 336 | } |
| 337 | |
| 338 | #endif |
| 339 | |
| 340 | /*----- That's all, folks -------------------------------------------------*/ |