[9] | 1 | /* glpdmp.c (dynamic memory pool) */ |
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| 2 | |
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| 3 | /*********************************************************************** |
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| 4 | * This code is part of GLPK (GNU Linear Programming Kit). |
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| 5 | * |
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| 6 | * Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, |
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| 7 | * 2009, 2010, 2011 Andrew Makhorin, Department for Applied Informatics, |
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| 8 | * Moscow Aviation Institute, Moscow, Russia. All rights reserved. |
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| 9 | * E-mail: <mao@gnu.org>. |
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| 10 | * |
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| 11 | * GLPK is free software: you can redistribute it and/or modify it |
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| 12 | * under the terms of the GNU General Public License as published by |
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| 13 | * the Free Software Foundation, either version 3 of the License, or |
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| 14 | * (at your option) any later version. |
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| 15 | * |
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| 16 | * GLPK is distributed in the hope that it will be useful, but WITHOUT |
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| 17 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
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| 18 | * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public |
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| 19 | * License for more details. |
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| 20 | * |
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| 21 | * You should have received a copy of the GNU General Public License |
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| 22 | * along with GLPK. If not, see <http://www.gnu.org/licenses/>. |
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| 23 | ***********************************************************************/ |
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| 24 | |
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| 25 | #include "glpdmp.h" |
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| 26 | |
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| 27 | #if 1 /* 29/VIII-2008 */ |
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| 28 | /* some processors need data to be properly aligned; the macro |
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| 29 | align_datasize enlarges the specified size of a data item to provide |
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| 30 | a proper alignment of immediately following data */ |
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| 31 | |
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| 32 | #define align_datasize(size) ((((size) + 7) / 8) * 8) |
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| 33 | /* 8 bytes is sufficient in both 32- and 64-bit environments */ |
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| 34 | #endif |
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| 35 | |
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| 36 | #ifdef GLP_DEBUG |
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| 37 | struct info |
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| 38 | { DMP *pool; |
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| 39 | int size; |
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| 40 | }; |
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| 41 | #endif |
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| 42 | |
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| 43 | /*********************************************************************** |
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| 44 | * NAME |
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| 45 | * |
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| 46 | * dmp_create_pool - create dynamic memory pool |
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| 47 | * |
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| 48 | * SYNOPSIS |
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| 49 | * |
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| 50 | * #include "glpdmp.h" |
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| 51 | * DMP *dmp_create_pool(void); |
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| 52 | * |
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| 53 | * DESCRIPTION |
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| 54 | * |
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| 55 | * The routine dmp_create_pool creates a dynamic memory pool. |
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| 56 | * |
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| 57 | * RETURNS |
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| 58 | * |
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| 59 | * The routine returns a pointer to the memory pool created. */ |
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| 60 | |
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| 61 | DMP *dmp_create_pool(void) |
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| 62 | { DMP *pool; |
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| 63 | int k; |
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| 64 | #ifdef GLP_DEBUG |
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| 65 | xprintf("dmp_create_pool: warning: debug mode enabled\n"); |
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| 66 | #endif |
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| 67 | pool = xmalloc(sizeof(DMP)); |
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| 68 | #if 0 |
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| 69 | pool->size = 0; |
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| 70 | #endif |
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| 71 | for (k = 0; k <= 31; k++) pool->avail[k] = NULL; |
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| 72 | pool->block = NULL; |
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| 73 | pool->used = DMP_BLK_SIZE; |
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| 74 | pool->count.lo = pool->count.hi = 0; |
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| 75 | return pool; |
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| 76 | } |
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| 77 | |
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| 78 | /*********************************************************************** |
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| 79 | * NAME |
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| 80 | * |
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| 81 | * dmp_get_atom - get free atom from dynamic memory pool |
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| 82 | * |
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| 83 | * SYNOPSIS |
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| 84 | * |
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| 85 | * #include "glpdmp.h" |
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| 86 | * void *dmp_get_atom(DMP *pool, int size); |
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| 87 | * |
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| 88 | * DESCRIPTION |
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| 89 | * |
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| 90 | * The routine dmp_get_atom obtains a free atom (memory block) from the |
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| 91 | * specified memory pool. |
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| 92 | * |
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| 93 | * The parameter size is the atom size, in bytes, 1 <= size <= 256. |
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| 94 | * |
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| 95 | * Note that the free atom contains arbitrary data, not binary zeros. |
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| 96 | * |
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| 97 | * RETURNS |
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| 98 | * |
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| 99 | * The routine returns a pointer to the free atom obtained. */ |
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| 100 | |
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| 101 | void *dmp_get_atom(DMP *pool, int size) |
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| 102 | { void *atom; |
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| 103 | int k; |
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| 104 | #ifdef GLP_DEBUG |
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| 105 | int orig_size = size; |
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| 106 | #endif |
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| 107 | if (!(1 <= size && size <= 256)) |
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| 108 | xerror("dmp_get_atom: size = %d; invalid atom size\n", size); |
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| 109 | #if 0 |
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| 110 | if (!(pool->size == 0 || pool->size == size)) |
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| 111 | xerror("dmp_get_atom: size = %d; wrong atom size\n", size); |
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| 112 | #endif |
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| 113 | /* adjust the size to provide the proper data alignment */ |
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| 114 | size = align_datasize(size); |
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| 115 | #ifdef GLP_DEBUG |
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| 116 | size += align_datasize(sizeof(struct info)); |
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| 117 | #endif |
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| 118 | /* adjust the size to make it multiple of 8 bytes, if needed */ |
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| 119 | size = ((size + 7) / 8) * 8; |
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| 120 | /* determine the corresponding list of free cells */ |
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| 121 | k = size / 8 - 1; |
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| 122 | xassert(0 <= k && k <= 31); |
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| 123 | /* obtain a free atom */ |
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| 124 | if (pool->avail[k] == NULL) |
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| 125 | { /* the list of free cells is empty */ |
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| 126 | if (pool->used + size > DMP_BLK_SIZE) |
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| 127 | { /* allocate a new memory block */ |
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| 128 | void *block = xmalloc(DMP_BLK_SIZE); |
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| 129 | *(void **)block = pool->block; |
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| 130 | pool->block = block; |
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| 131 | pool->used = align_datasize(sizeof(void *)); |
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| 132 | } |
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| 133 | /* place the atom in the current memory block */ |
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| 134 | atom = (char *)pool->block + pool->used; |
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| 135 | pool->used += size; |
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| 136 | } |
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| 137 | else |
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| 138 | { /* obtain the atom from the list of free cells */ |
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| 139 | atom = pool->avail[k]; |
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| 140 | pool->avail[k] = *(void **)atom; |
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| 141 | } |
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| 142 | memset(atom, '?', size); |
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| 143 | /* increase the number of atoms which are currently in use */ |
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| 144 | pool->count.lo++; |
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| 145 | if (pool->count.lo == 0) pool->count.hi++; |
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| 146 | #ifdef GLP_DEBUG |
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| 147 | ((struct info *)atom)->pool = pool; |
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| 148 | ((struct info *)atom)->size = orig_size; |
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| 149 | atom = (char *)atom + align_datasize(sizeof(struct info)); |
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| 150 | #endif |
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| 151 | return atom; |
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| 152 | } |
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| 153 | |
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| 154 | /*********************************************************************** |
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| 155 | * NAME |
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| 156 | * |
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| 157 | * dmp_free_atom - return atom to dynamic memory pool |
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| 158 | * |
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| 159 | * SYNOPSIS |
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| 160 | * |
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| 161 | * #include "glpdmp.h" |
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| 162 | * void dmp_free_atom(DMP *pool, void *atom, int size); |
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| 163 | * |
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| 164 | * DESCRIPTION |
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| 165 | * |
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| 166 | * The routine dmp_free_atom returns the specified atom (memory block) |
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| 167 | * to the specified memory pool, making it free. |
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| 168 | * |
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| 169 | * The parameter size is the atom size, in bytes, 1 <= size <= 256. |
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| 170 | * |
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| 171 | * Note that the atom can be returned only to the pool, from which it |
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| 172 | * was obtained, and its size must be exactly the same as on obtaining |
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| 173 | * it from the pool. */ |
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| 174 | |
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| 175 | void dmp_free_atom(DMP *pool, void *atom, int size) |
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| 176 | { int k; |
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| 177 | if (!(1 <= size && size <= 256)) |
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| 178 | xerror("dmp_free_atom: size = %d; invalid atom size\n", size); |
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| 179 | #if 0 |
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| 180 | if (!(pool->size == 0 || pool->size == size)) |
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| 181 | xerror("dmp_free_atom: size = %d; wrong atom size\n", size); |
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| 182 | #endif |
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| 183 | if (pool->count.lo == 0 && pool->count.hi == 0) |
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| 184 | xerror("dmp_free_atom: pool allocation error\n"); |
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| 185 | #ifdef GLP_DEBUG |
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| 186 | atom = (char *)atom - align_datasize(sizeof(struct info)); |
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| 187 | xassert(((struct info *)atom)->pool == pool); |
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| 188 | xassert(((struct info *)atom)->size == size); |
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| 189 | #endif |
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| 190 | /* adjust the size to provide the proper data alignment */ |
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| 191 | size = align_datasize(size); |
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| 192 | #ifdef GLP_DEBUG |
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| 193 | size += align_datasize(sizeof(struct info)); |
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| 194 | #endif |
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| 195 | /* adjust the size to make it multiple of 8 bytes, if needed */ |
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| 196 | size = ((size + 7) / 8) * 8; |
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| 197 | /* determine the corresponding list of free cells */ |
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| 198 | k = size / 8 - 1; |
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| 199 | xassert(0 <= k && k <= 31); |
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| 200 | /* return the atom to the list of free cells */ |
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| 201 | *(void **)atom = pool->avail[k]; |
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| 202 | pool->avail[k] = atom; |
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| 203 | /* decrease the number of atoms which are currently in use */ |
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| 204 | pool->count.lo--; |
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| 205 | if (pool->count.lo == 0xFFFFFFFF) pool->count.hi--; |
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| 206 | return; |
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| 207 | } |
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| 208 | |
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| 209 | /*********************************************************************** |
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| 210 | * NAME |
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| 211 | * |
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| 212 | * dmp_in_use - determine how many atoms are still in use |
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| 213 | * |
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| 214 | * SYNOPSIS |
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| 215 | * |
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| 216 | * #include "glpdmp.h" |
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| 217 | * glp_long dmp_in_use(DMP *pool); |
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| 218 | * |
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| 219 | * DESCRIPTION |
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| 220 | * |
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| 221 | * The routine dmp_in_use determines how many atoms allocated from the |
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| 222 | * specified memory pool with the routine dmp_get_atom are still in use, |
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| 223 | * i.e. not returned to the pool with the routine dmp_free_atom. |
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| 224 | * |
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| 225 | * RETURNS |
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| 226 | * |
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| 227 | * The routine returns the number of atoms which are still in use. */ |
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| 228 | |
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| 229 | glp_long dmp_in_use(DMP *pool) |
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| 230 | { return |
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| 231 | pool->count; |
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| 232 | } |
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| 233 | |
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| 234 | /*********************************************************************** |
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| 235 | * NAME |
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| 236 | * |
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| 237 | * dmp_delete_pool - delete dynamic memory pool |
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| 238 | * |
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| 239 | * SYNOPSIS |
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| 240 | * |
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| 241 | * #include "glpdmp.h" |
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| 242 | * void dmp_delete_pool(DMP *pool); |
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| 243 | * |
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| 244 | * DESCRIPTION |
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| 245 | * |
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| 246 | * The routine dmp_delete_pool deletes the specified dynamic memory |
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| 247 | * pool and frees all the memory allocated to this object. */ |
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| 248 | |
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| 249 | void dmp_delete_pool(DMP *pool) |
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| 250 | { while (pool->block != NULL) |
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| 251 | { void *block = pool->block; |
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| 252 | pool->block = *(void **)block; |
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| 253 | xfree(block); |
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| 254 | } |
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| 255 | xfree(pool); |
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| 256 | return; |
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| 257 | } |
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| 258 | |
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| 259 | /* eof */ |
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