| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: mparena.c,v 1.1 1999/11/17 18:02:16 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 | /*----- Revision history --------------------------------------------------* |
| 31 | * |
| 32 | * $Log: mparena.c,v $ |
| 33 | * Revision 1.1 1999/11/17 18:02:16 mdw |
| 34 | * New multiprecision integer arithmetic suite. |
| 35 | * |
| 36 | */ |
| 37 | |
| 38 | /*----- Header files ------------------------------------------------------*/ |
| 39 | |
| 40 | #include <stdio.h> |
| 41 | #include <stdlib.h> |
| 42 | #include <string.h> |
| 43 | |
| 44 | #include <mLib/alloc.h> |
| 45 | #include <mLib/sub.h> |
| 46 | |
| 47 | #include "mparena.h" |
| 48 | |
| 49 | /*----- Default allocator -------------------------------------------------*/ |
| 50 | |
| 51 | static void *defalloc(mparena *a, size_t sz) { return xmalloc(sz); } |
| 52 | static void deffree(mparena *a, void *p) { free(p); } |
| 53 | |
| 54 | mparena_ops mparena_defops = { defalloc, deffree }; |
| 55 | |
| 56 | /*----- Static variables --------------------------------------------------*/ |
| 57 | |
| 58 | static mparena arena = { 0, &mparena_defops }; |
| 59 | |
| 60 | #define MPARENA_RESOLVE(a) do { \ |
| 61 | if ((a) == MPARENA_GLOBAL) \ |
| 62 | (a) = &arena; \ |
| 63 | } while (0) |
| 64 | |
| 65 | /*----- Main code ---------------------------------------------------------*/ |
| 66 | |
| 67 | /* --- @tdump@ --- * |
| 68 | * |
| 69 | * Arguments: @mparena_node *n@ = pointer to tree node to dump |
| 70 | * |
| 71 | * Returns: --- |
| 72 | * |
| 73 | * Use: Recursively dumps out the allocation tree. |
| 74 | */ |
| 75 | |
| 76 | static void tdump(mparena_node *n) |
| 77 | { |
| 78 | if (!n) |
| 79 | putchar('*'); |
| 80 | else { |
| 81 | putchar('('); |
| 82 | tdump(n->left); |
| 83 | printf(", %u, ", n->v[0]); |
| 84 | tdump(n->right); |
| 85 | putchar(')'); |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | /* --- @mparena_create@ --- * |
| 90 | * |
| 91 | * Arguments: @mparena *a@ = pointer to arena block |
| 92 | * |
| 93 | * Returns: --- |
| 94 | * |
| 95 | * Use: Initializes an MP arena so that blocks can be allocated from |
| 96 | * it. |
| 97 | */ |
| 98 | |
| 99 | void mparena_create(mparena *a) |
| 100 | { |
| 101 | a->root = 0; |
| 102 | a->ops = &mparena_defops; |
| 103 | } |
| 104 | |
| 105 | /* --- @mparena_setops@ --- * |
| 106 | * |
| 107 | * Arguments: @mparena *a@ = pointer to arena block |
| 108 | * @mparena_ops *ops@ = pointer to operations block or null |
| 109 | * |
| 110 | * Returns: The previous operations block. |
| 111 | * |
| 112 | * Use: Sets or queries the operations attached to an arena. |
| 113 | */ |
| 114 | |
| 115 | mparena_ops *mparena_setops(mparena *a, mparena_ops *ops) |
| 116 | { |
| 117 | mparena_ops *o; |
| 118 | MPARENA_RESOLVE(a); |
| 119 | o = a->ops; |
| 120 | if (ops) |
| 121 | a->ops = ops; |
| 122 | return (0); |
| 123 | } |
| 124 | |
| 125 | /* --- @mparena_destroy@ --- * |
| 126 | * |
| 127 | * Arguments: @mparena *a@ = pointer to arena block |
| 128 | * |
| 129 | * Returns: --- |
| 130 | * |
| 131 | * Use: Frees an MP arena, and all the vectors held within it. The |
| 132 | * blocks which are currently allocated can be freed into some |
| 133 | * other arena. |
| 134 | */ |
| 135 | |
| 136 | static void tfree(mparena *a, mparena_node *n) |
| 137 | { |
| 138 | a->ops->free(a, n->v); |
| 139 | if (n->left) |
| 140 | tfree(a, n->left); |
| 141 | if (n->right) |
| 142 | tfree(a, n->right); |
| 143 | DESTROY(n); |
| 144 | } |
| 145 | |
| 146 | void mparena_destroy(mparena *a) |
| 147 | { |
| 148 | tfree(a, a->root); |
| 149 | a->root = 0; |
| 150 | } |
| 151 | |
| 152 | /* --- @mpalloc@ --- * |
| 153 | * |
| 154 | * Arguments: @mparena *a@ = pointer to arena block |
| 155 | * @size_t sz@ = number of digits required |
| 156 | * |
| 157 | * Returns: Pointer to a suitably sized block. |
| 158 | * |
| 159 | * Use: Allocates a lump of data suitable for use as an array of MP |
| 160 | * digits. |
| 161 | */ |
| 162 | |
| 163 | mpw *mpalloc(mparena *a, size_t sz) |
| 164 | { |
| 165 | mparena_node **nn, *n; |
| 166 | mpw *v; |
| 167 | |
| 168 | MPARENA_RESOLVE(a); |
| 169 | nn = &a->root; |
| 170 | |
| 171 | #ifdef notdef |
| 172 | printf("*** alloc %u\n", sz); |
| 173 | tdump(a->root); putchar('\n'); |
| 174 | #endif |
| 175 | |
| 176 | /* --- First, find a block which is big enough --- */ |
| 177 | |
| 178 | again: |
| 179 | n = *nn; |
| 180 | if (!n) { |
| 181 | v = a->ops->alloc(a, MPWS(sz + 1)); |
| 182 | v[0] = sz; |
| 183 | return (v + 1); |
| 184 | } |
| 185 | if (n->v[0] < sz) { |
| 186 | nn = &n->right; |
| 187 | goto again; |
| 188 | } |
| 189 | |
| 190 | /* --- Now try to find a smaller block which is suitable --- */ |
| 191 | |
| 192 | while (n->left && n->left->v[0] >= sz) { |
| 193 | nn = &n->left; |
| 194 | n = *nn; |
| 195 | } |
| 196 | |
| 197 | /* --- If the block we've got is still too large, start digging --- */ |
| 198 | |
| 199 | if (n->v[0] >= sz * 2) { |
| 200 | nn = &n->left; |
| 201 | goto again; |
| 202 | } |
| 203 | |
| 204 | /* --- I've now found a suitable block --- */ |
| 205 | |
| 206 | v = n->v; |
| 207 | |
| 208 | /* --- Remove this node from the tree --- */ |
| 209 | |
| 210 | if (!n->left) |
| 211 | *nn = n->right; |
| 212 | else if (!n->right) |
| 213 | *nn = n->left; |
| 214 | else { |
| 215 | mparena_node *left = n->left; |
| 216 | mparena_node *p = *nn = n->right; |
| 217 | while (p->left) |
| 218 | p = p->left; |
| 219 | p->left = left; |
| 220 | } |
| 221 | |
| 222 | /* --- Get rid of this node now --- */ |
| 223 | |
| 224 | DESTROY(n); |
| 225 | return (v + 1); |
| 226 | } |
| 227 | |
| 228 | /* --- @mpfree@ --- * |
| 229 | * |
| 230 | * Arguments: @mparena *a@ = pointer to arena block |
| 231 | * @mpw *v@ = pointer to allocated vector |
| 232 | * |
| 233 | * Returns: --- |
| 234 | * |
| 235 | * Use: Returns an MP vector to an arena. It doesn't have to be |
| 236 | * returned to the arena from which it was allocated. |
| 237 | */ |
| 238 | |
| 239 | void mpfree(mparena *a, mpw *v) |
| 240 | { |
| 241 | mparena_node **nn, *n; |
| 242 | size_t sz = *--v; |
| 243 | |
| 244 | MPARENA_RESOLVE(a); |
| 245 | nn = &a->root; |
| 246 | |
| 247 | while (*nn) { |
| 248 | n = *nn; |
| 249 | if (n->v[0] > sz) |
| 250 | nn = &n->left; |
| 251 | else |
| 252 | nn = &n->right; |
| 253 | } |
| 254 | |
| 255 | n = CREATE(mparena_node); |
| 256 | n->left = n->right = 0; |
| 257 | n->v = v; |
| 258 | *nn = n; |
| 259 | |
| 260 | #ifdef notdef |
| 261 | printf("*** free %u\n", sz); |
| 262 | tdump(a->root); putchar('\n'); |
| 263 | #endif |
| 264 | } |
| 265 | |
| 266 | /*----- That's all, folks -------------------------------------------------*/ |