[5] | 1 | /* |
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| 2 | * tclAlloc.c -- |
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| 3 | * |
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| 4 | * This is a very fast storage allocator. It allocates blocks of a |
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| 5 | * small number of different sizes, and keeps free lists of each size. |
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| 6 | * Blocks that don't exactly fit are passed up to the next larger size. |
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| 7 | * Blocks over a certain size are directly allocated from the system. |
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| 8 | * |
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| 9 | * Copyright (c) 1983 Regents of the University of California. |
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| 10 | * Copyright (c) 1996-1997 Sun Microsystems, Inc. |
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| 11 | * |
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| 12 | * Portions contributed by Chris Kingsley, Jack Jansen and Ray Johnson. |
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| 13 | * |
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| 14 | * See the file "license.terms" for information on usage and redistribution |
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| 15 | * of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
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| 16 | * |
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| 17 | * RCS: @(#) $Id: tclAlloc.c,v 1.1 2008-06-04 13:58:03 demin Exp $ |
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| 18 | */ |
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| 19 | |
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| 20 | #include "tclInt.h" |
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| 21 | #include "tclPort.h" |
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| 22 | |
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| 23 | #ifdef TCL_DEBUG |
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| 24 | # define DEBUG |
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| 25 | /* #define MSTATS */ |
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| 26 | # define RCHECK |
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| 27 | #endif |
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| 28 | |
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| 29 | //typedef unsigned long caddr_t; |
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| 30 | |
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| 31 | /* |
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| 32 | * The overhead on a block is at least 4 bytes. When free, this space |
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| 33 | * contains a pointer to the next free block, and the bottom two bits must |
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| 34 | * be zero. When in use, the first byte is set to MAGIC, and the second |
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| 35 | * byte is the size index. The remaining bytes are for alignment. |
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| 36 | * If range checking is enabled then a second word holds the size of the |
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| 37 | * requested block, less 1, rounded up to a multiple of sizeof(RMAGIC). |
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| 38 | * The order of elements is critical: ov_magic must overlay the low order |
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| 39 | * bits of ov_next, and ov_magic can not be a valid ov_next bit pattern. |
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| 40 | */ |
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| 41 | |
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| 42 | union overhead { |
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| 43 | union overhead *ov_next; /* when free */ |
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| 44 | struct { |
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| 45 | unsigned char ovu_magic0; /* magic number */ |
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| 46 | unsigned char ovu_index; /* bucket # */ |
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| 47 | unsigned char ovu_unused; /* unused */ |
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| 48 | unsigned char ovu_magic1; /* other magic number */ |
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| 49 | #ifdef RCHECK |
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| 50 | unsigned short ovu_rmagic; /* range magic number */ |
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| 51 | unsigned long ovu_size; /* actual block size */ |
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| 52 | #endif |
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| 53 | } ovu; |
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| 54 | #define ov_magic0 ovu.ovu_magic0 |
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| 55 | #define ov_magic1 ovu.ovu_magic1 |
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| 56 | #define ov_index ovu.ovu_index |
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| 57 | #define ov_rmagic ovu.ovu_rmagic |
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| 58 | #define ov_size ovu.ovu_size |
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| 59 | }; |
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| 60 | |
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| 61 | |
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| 62 | #define MAGIC 0xef /* magic # on accounting info */ |
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| 63 | #define RMAGIC 0x5555 /* magic # on range info */ |
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| 64 | |
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| 65 | #ifdef RCHECK |
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| 66 | #define RSLOP sizeof (unsigned short) |
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| 67 | #else |
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| 68 | #define RSLOP 0 |
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| 69 | #endif |
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| 70 | |
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| 71 | #define OVERHEAD (sizeof(union overhead) + RSLOP) |
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| 72 | |
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| 73 | /* |
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| 74 | * nextf[i] is the pointer to the next free block of size 2^(i+3). The |
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| 75 | * smallest allocatable block is 8 bytes. The overhead information |
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| 76 | * precedes the data area returned to the user. |
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| 77 | */ |
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| 78 | |
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| 79 | #define NBUCKETS 13 |
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| 80 | #define MAXMALLOC (1<<(NBUCKETS+2)) |
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| 81 | |
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| 82 | #ifdef MSTATS |
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| 83 | |
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| 84 | /* |
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| 85 | * nmalloc[i] is the difference between the number of mallocs and frees |
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| 86 | * for a given block size. |
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| 87 | */ |
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| 88 | |
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| 89 | static unsigned int nmalloc[NBUCKETS+1]; |
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| 90 | #include <stdio.h> |
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| 91 | #endif |
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| 92 | |
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| 93 | #if defined(DEBUG) || defined(RCHECK) |
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| 94 | #define ASSERT(p) if (!(p)) panic(# p) |
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| 95 | #define RANGE_ASSERT(p) if (!(p)) panic(# p) |
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| 96 | #else |
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| 97 | #define ASSERT(p) |
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| 98 | #define RANGE_ASSERT(p) |
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| 99 | #endif |
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| 100 | |
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| 101 | /* |
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| 102 | *---------------------------------------------------------------------- |
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| 103 | * |
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| 104 | * TclpAlloc -- |
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| 105 | * |
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| 106 | * Allocate more memory. |
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| 107 | * |
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| 108 | * Results: |
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| 109 | * None. |
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| 110 | * |
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| 111 | * Side effects: |
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| 112 | * None. |
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| 113 | * |
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| 114 | *---------------------------------------------------------------------- |
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| 115 | */ |
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| 116 | |
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| 117 | char * |
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| 118 | TclpAlloc( |
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| 119 | unsigned int nbytes) /* Number of bytes to allocate. */ |
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| 120 | { |
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| 121 | return (char*) malloc(nbytes); |
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| 122 | } |
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| 123 | |
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| 124 | /* |
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| 125 | *---------------------------------------------------------------------- |
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| 126 | * |
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| 127 | * TclpFree -- |
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| 128 | * |
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| 129 | * Free memory. |
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| 130 | * |
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| 131 | * Results: |
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| 132 | * None. |
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| 133 | * |
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| 134 | * Side effects: |
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| 135 | * None. |
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| 136 | * |
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| 137 | *---------------------------------------------------------------------- |
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| 138 | */ |
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| 139 | |
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| 140 | void |
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| 141 | TclpFree( |
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| 142 | char *cp) /* Pointer to memory to free. */ |
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| 143 | { |
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| 144 | free(cp); |
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| 145 | return; |
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| 146 | } |
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| 147 | |
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| 148 | /* |
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| 149 | *---------------------------------------------------------------------- |
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| 150 | * |
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| 151 | * TclpRealloc -- |
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| 152 | * |
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| 153 | * Reallocate memory. |
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| 154 | * |
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| 155 | * Results: |
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| 156 | * None. |
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| 157 | * |
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| 158 | * Side effects: |
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| 159 | * None. |
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| 160 | * |
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| 161 | *---------------------------------------------------------------------- |
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| 162 | */ |
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| 163 | |
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| 164 | char * |
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| 165 | TclpRealloc( |
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| 166 | char *cp, /* Pointer to alloced block. */ |
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| 167 | unsigned int nbytes) /* New size of memory. */ |
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| 168 | { |
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| 169 | return (char*) realloc(cp, nbytes); |
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| 170 | } |
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| 171 | |
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| 172 | /* |
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| 173 | *---------------------------------------------------------------------- |
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| 174 | * |
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| 175 | * mstats -- |
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| 176 | * |
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| 177 | * Prints two lines of numbers, one showing the length of the |
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| 178 | * free list for each size category, the second showing the |
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| 179 | * number of mallocs - frees for each size category. |
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| 180 | * |
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| 181 | * Results: |
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| 182 | * None. |
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| 183 | * |
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| 184 | * Side effects: |
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| 185 | * None. |
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| 186 | * |
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| 187 | *---------------------------------------------------------------------- |
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| 188 | */ |
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| 189 | |
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| 190 | #ifdef MSTATS |
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| 191 | void |
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| 192 | mstats( |
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| 193 | char *s) /* Where to write info. */ |
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| 194 | { |
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| 195 | register int i, j; |
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| 196 | register union overhead *p; |
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| 197 | int totfree = 0, |
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| 198 | totused = 0; |
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| 199 | |
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| 200 | fprintf(stderr, "Memory allocation statistics %s\nTclpFree:\t", s); |
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| 201 | for (i = 0; i < NBUCKETS; i++) { |
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| 202 | for (j = 0, p = nextf[i]; p; p = p->ov_next, j++) |
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| 203 | fprintf(stderr, " %d", j); |
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| 204 | totfree += j * (1 << (i + 3)); |
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| 205 | } |
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| 206 | fprintf(stderr, "\nused:\t"); |
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| 207 | for (i = 0; i < NBUCKETS; i++) { |
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| 208 | fprintf(stderr, " %d", nmalloc[i]); |
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| 209 | totused += nmalloc[i] * (1 << (i + 3)); |
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| 210 | } |
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| 211 | fprintf(stderr, "\n\tTotal small in use: %d, total free: %d\n", |
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| 212 | totused, totfree); |
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| 213 | fprintf(stderr, "\n\tNumber of big (>%d) blocks in use: %d\n", |
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| 214 | MAXMALLOC, nmalloc[NBUCKETS]); |
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| 215 | } |
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| 216 | #endif |
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| 217 | |
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