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0875b58f | 1 | /* -*-c-*- |
2 | * | |
8656dc50 | 3 | * $Id: sub.h,v 1.8 2004/04/08 01:36:13 mdw Exp $ |
0875b58f | 4 | * |
5 | * Allocation of known-size blocks | |
6 | * | |
7 | * (c) 1998 Straylight/Edgeware | |
8 | */ | |
9 | ||
d4efbcd9 | 10 | /*----- Licensing notice --------------------------------------------------* |
0875b58f | 11 | * |
12 | * This file is part of the mLib utilities library. | |
13 | * | |
14 | * mLib is free software; you can redistribute it and/or modify | |
c846879c | 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. | |
d4efbcd9 | 18 | * |
0875b58f | 19 | * mLib 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 | |
c846879c | 22 | * GNU Library General Public License for more details. |
d4efbcd9 | 23 | * |
c846879c | 24 | * You should have received a copy of the GNU Library General Public |
0bd98442 | 25 | * License along with mLib; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
27 | * MA 02111-1307, USA. | |
0875b58f | 28 | */ |
29 | ||
c6e0eaf0 | 30 | #ifndef MLIB_SUB_H |
31 | #define MLIB_SUB_H | |
0875b58f | 32 | |
33 | #ifdef __cplusplus | |
34 | extern "C" { | |
35 | #endif | |
36 | ||
37 | /*----- Required header files ---------------------------------------------*/ | |
38 | ||
39 | #include <stdlib.h> | |
40 | ||
c5775f49 | 41 | #ifndef MLIB_ALIGN_H |
42 | # include "align.h" | |
43 | #endif | |
44 | ||
0fd574c3 | 45 | #ifndef MLIB_ARENA_H |
46 | # include "arena.h" | |
0875b58f | 47 | #endif |
48 | ||
0fd574c3 | 49 | /*----- Configuration and tuning ------------------------------------------*/ |
50 | ||
51 | /* --- The largest block I'll handle here --- * | |
52 | * | |
53 | * Anything larger will be handed on to the underlying @alloc@. | |
54 | */ | |
55 | ||
56 | #define SUB_MAXBIN 256 | |
57 | ||
58 | /* --- Preferred chunk size --- * | |
59 | * | |
60 | * When a bin is empty, I'll allocate a large chunk of approximately this | |
61 | * size and divvy it up into small bin-sized blocks. | |
62 | */ | |
63 | ||
64 | #define SUB_CHUNK 4096 | |
65 | ||
66 | /*----- Other useful macros -----------------------------------------------*/ | |
67 | ||
68 | /* --- The granularity of bin buffers --- * | |
69 | * | |
c5775f49 | 70 | * All blocks allocated by the binner are a multiple of this size. |
0fd574c3 | 71 | */ |
72 | ||
c5775f49 | 73 | #define SUB_GRANULE sizeof(union align) |
0fd574c3 | 74 | |
75 | /* --- Finding the right bin for a given size --- * | |
76 | * | |
77 | * This chooses the correct bin for an allocation. Input is the size of | |
78 | * block wanted; result is the bin index. | |
79 | */ | |
80 | ||
81 | #define SUB_BIN(x) (((x) + SUB_GRANULE - 1) / SUB_GRANULE) | |
82 | ||
83 | /* --- Convert a bin back to the block size --- * | |
84 | * | |
85 | * This gives the size of block contained in a given bin. | |
86 | */ | |
87 | ||
88 | #define SUB_BINSZ(x) ((x) * SUB_GRANULE) | |
89 | ||
90 | /* --- Number of bins required --- */ | |
91 | ||
92 | #define SUB_BINS (SUB_MAXBIN / SUB_GRANULE + 1) | |
93 | ||
94 | /*----- Data structures ---------------------------------------------------*/ | |
95 | ||
96 | typedef struct subarena { | |
97 | arena *a; | |
98 | void *bin[SUB_BINS]; | |
99 | } subarena; | |
100 | ||
101 | /*----- Global variables --------------------------------------------------*/ | |
102 | ||
103 | extern subarena sub_global; | |
104 | ||
0875b58f | 105 | /*----- Functions provided ------------------------------------------------*/ |
106 | ||
0fd574c3 | 107 | /* --- @subarena_create@ --- * |
108 | * | |
109 | * Arguments: @subarena *s@ = pointer to arena to initialize | |
110 | * @arena *a@ = pointer to underlying arena block | |
111 | * | |
112 | * Returns: --- | |
113 | * | |
114 | * Use: Initialize a suballocation arena based on an underlying large | |
115 | * blocks arena. | |
116 | */ | |
117 | ||
118 | extern void subarena_create(subarena */*s*/, arena */*a*/); | |
119 | ||
120 | /* --- @subarena_destroy@ --- * | |
121 | * | |
122 | * Arguments: @subarena *s@ = pointer to arena to destroy | |
123 | * | |
124 | * Returns: --- | |
125 | * | |
126 | * Use: Destroys a suballocation arena, freeing all of the memory it | |
127 | * contains back to the underlying large blocks arena. | |
128 | */ | |
129 | ||
130 | extern void subarena_destroy(subarena */*s*/); | |
131 | ||
132 | /* --- @subarena_alloc@ --- * | |
133 | * | |
134 | * Arguments: @subarena *s@ = pointer to arena | |
135 | * @size_t s@ = size of chunk wanted | |
136 | * | |
d4efbcd9 | 137 | * Returns: Pointer to a block at least as large as the one wanted. |
0fd574c3 | 138 | * |
d4efbcd9 | 139 | * Use: Allocates a small block of memory from the given pool. The |
0fd574c3 | 140 | * exception @EXC_NOMEM@ is raised if the underlying arena is |
141 | * full. | |
142 | */ | |
143 | ||
144 | extern void *subarena_alloc(subarena */*s*/, size_t /*sz*/); | |
145 | ||
146 | /* --- @subarena_free@ --- * | |
147 | * | |
d4efbcd9 | 148 | * Arguments: @subarena *s@ = pointer to arena |
0fd574c3 | 149 | * @void *p@ = address of block to free |
d4efbcd9 | 150 | * @size_t s@ = size of block |
0fd574c3 | 151 | * |
d4efbcd9 | 152 | * Returns: --- |
0fd574c3 | 153 | * |
d4efbcd9 | 154 | * Use: Frees a block allocated by @subarena_alloc@. |
0fd574c3 | 155 | */ |
156 | ||
157 | extern void subarena_free(subarena */*s*/, void */*p*/, size_t /*sz*/); | |
158 | ||
159 | /* --- @A_CREATE@ --- * | |
160 | * | |
161 | * Arguments: @subarena *s@ = pointer to arena | |
162 | * @type@ = type of object required; must be passable to | |
163 | * @sizeof@ | |
164 | * | |
165 | * Returns: Pointer to a block sufficiently big to hold an object of the | |
166 | * named type. | |
167 | * | |
168 | * Use: Allocates a block of the required type. | |
169 | */ | |
170 | ||
171 | #define A_CREATE(a, type) subarena_alloc((a), sizeof(type)) | |
172 | ||
173 | /* --- @A_DESTROY@ --- * | |
174 | * | |
175 | * Arguments: @subarena *s@ = pointer to arena | |
176 | * @void *p@ = pointer to an object | |
177 | * | |
178 | * Returns: --- | |
179 | * | |
180 | * Use: Frees the thing pointed to by @p@. | |
181 | */ | |
182 | ||
183 | #define A_DESTROY(a, p) subarena_free((a), (p), sizeof(*p)) | |
184 | ||
185 | /*----- Shortcuts for the global pool -------------------------------------*/ | |
186 | ||
0875b58f | 187 | /* --- @sub_alloc@ --- * |
188 | * | |
d4efbcd9 | 189 | * Arguments: @size_t s@ = size of chunk wanted |
0875b58f | 190 | * |
d4efbcd9 | 191 | * Returns: Pointer to a block at least as large as the one wanted. |
0875b58f | 192 | * |
d4efbcd9 | 193 | * Use: Allocates a small block of memory from the @sub_global@ pool. |
0875b58f | 194 | */ |
195 | ||
0fd574c3 | 196 | extern void *sub_alloc(size_t /*sz*/); |
197 | #define sub_alloc(sz) subarena_alloc(&sub_global, (sz)) | |
0875b58f | 198 | |
199 | /* --- @sub_free@ --- * | |
200 | * | |
d4efbcd9 MW |
201 | * Arguments: @void *p@ = address of block to free |
202 | * @size_t s@ = size of block | |
0875b58f | 203 | * |
d4efbcd9 | 204 | * Returns: --- |
0875b58f | 205 | * |
d4efbcd9 | 206 | * Use: Frees a block allocated by @sub_alloc@. |
0875b58f | 207 | */ |
208 | ||
0fd574c3 | 209 | extern void sub_free(void */*p*/, size_t /*sz*/); |
210 | #define sub_free(p, sz) subarena_free(&sub_global, (p), (sz)) | |
0875b58f | 211 | |
212 | /* --- @CREATE@ --- * | |
213 | * | |
214 | * Arguments: @type@ = type of object required; must be passable to | |
215 | * @sizeof@ | |
216 | * | |
217 | * Returns: Pointer to a block sufficiently big to hold an object of the | |
218 | * named type. | |
219 | * | |
220 | * Use: Allocates a block of the required type. | |
221 | */ | |
222 | ||
223 | #define CREATE(type) sub_alloc(sizeof(type)) | |
224 | ||
225 | /* --- @DESTROY@ --- * | |
226 | * | |
227 | * Arguments: @void *p@ = pointer to an object | |
228 | * | |
229 | * Returns: --- | |
230 | * | |
231 | * Use: Frees the thing pointed to by @p@. | |
232 | */ | |
233 | ||
234 | #define DESTROY(p) sub_free(p, sizeof(*p)) | |
235 | ||
236 | /* --- @sub_init@ --- * | |
237 | * | |
d4efbcd9 | 238 | * Arguments: --- |
0875b58f | 239 | * |
d4efbcd9 | 240 | * Returns: --- |
0875b58f | 241 | * |
d4efbcd9 | 242 | * Use: Initializes the magic allocator. This is no longer |
0fd574c3 | 243 | * necessary. |
0875b58f | 244 | */ |
245 | ||
0fd574c3 | 246 | extern void sub_init(void); |
0875b58f | 247 | |
248 | /*----- That's all, folks -------------------------------------------------*/ | |
249 | ||
250 | #ifdef __cplusplus | |
251 | } | |
252 | #endif | |
253 | ||
254 | #endif |