wsutil/wmem/wmem_allocator_simple.c

   1 /* wmem_allocator_simple.c
   2  * Wireshark Memory Manager Simple Allocator
   3  * Copyright 2012, Evan Huus <eapache@gmail.com>
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11
  12 #include "config.h"
  13
  14 #include <string.h>
  15
  16 #include <glib.h>
  17
  18 #include "wmem_core.h"
  19 #include "wmem_allocator.h"
  20 #include "wmem_allocator_simple.h"
  21
  22 #define DEFAULT_ALLOCS 8192
  23
  24 typedef struct _wmem_simple_allocator_t {
  25     int size;
  26     int count;
  27     void **ptrs;
  28 } wmem_simple_allocator_t;
  29
  30 static void *
  31 wmem_simple_alloc(void *private_data, const size_t size)
  32 {
  33     wmem_simple_allocator_t *allocator;
  34
  35     allocator = (wmem_simple_allocator_t*) private_data;
  36
  37     if (G_UNLIKELY(allocator->count == allocator->size)) {
  38         allocator->size *= 2;
  39         allocator->ptrs = (void**)wmem_realloc(NULL, allocator->ptrs,
  40                 sizeof(void*) * allocator->size);
  41     }
  42
  43     return allocator->ptrs[allocator->count++] = wmem_alloc(NULL, size);
  44 }
  45
  46 static void
  47 wmem_simple_free(void *private_data, void *ptr)
  48 {
  49     int                      i;
  50     wmem_simple_allocator_t *allocator;
  51
  52     allocator = (wmem_simple_allocator_t*) private_data;
  53
  54     wmem_free(NULL, ptr);
  55     allocator->count--;
  56
  57     for (i=allocator->count; i>=0; i--) {
  58         if (ptr == allocator->ptrs[i]) {
  59             if (i < allocator->count) {
  60                 allocator->ptrs[i] = allocator->ptrs[allocator->count];
  61             }
  62             return;
  63         }
  64     }
  65
  66     g_assert_not_reached();
  67 }
  68
  69 static void *
  70 wmem_simple_realloc(void *private_data, void *ptr, const size_t size)
  71 {
  72     int                      i;
  73     wmem_simple_allocator_t *allocator;
  74
  75     allocator = (wmem_simple_allocator_t*) private_data;
  76
  77     for (i=allocator->count-1; i>=0; i--) {
  78         if (ptr == allocator->ptrs[i]) {
  79             return allocator->ptrs[i] = wmem_realloc(NULL, allocator->ptrs[i], size);
  80         }
  81     }
  82
  83     g_assert_not_reached();
  84     /* not reached */
  85     return NULL;
  86 }
  87
  88 static void
  89 wmem_simple_free_all(void *private_data)
  90 {
  91     wmem_simple_allocator_t *allocator;
  92     int i;
  93
  94     allocator = (wmem_simple_allocator_t*) private_data;
  95
  96     for (i = 0; i<allocator->count; i++) {
  97         wmem_free(NULL, allocator->ptrs[i]);
  98     }
  99     allocator->count = 0;
 100 }
 101
 102 static void
 103 wmem_simple_gc(void *private_data _U_)
 104 {
 105     /* In this simple allocator, there is nothing to garbage-collect */
 106 }
 107
 108 static void
 109 wmem_simple_allocator_cleanup(void *private_data)
 110 {
 111     wmem_simple_allocator_t *allocator;
 112
 113     allocator = (wmem_simple_allocator_t*) private_data;
 114
 115     wmem_free(NULL, allocator->ptrs);
 116     wmem_free(NULL, allocator);
 117 }
 118
 119 void
 120 wmem_simple_allocator_init(wmem_allocator_t *allocator)
 121 {
 122     wmem_simple_allocator_t *simple_allocator;
 123
 124     simple_allocator = wmem_new(NULL, wmem_simple_allocator_t);
 125
 126     allocator->walloc   = &wmem_simple_alloc;
 127     allocator->wrealloc = &wmem_simple_realloc;
 128     allocator->wfree    = &wmem_simple_free;
 129
 130     allocator->free_all = &wmem_simple_free_all;
 131     allocator->gc       = &wmem_simple_gc;
 132     allocator->cleanup  = &wmem_simple_allocator_cleanup;
 133
 134     allocator->private_data = (void*) simple_allocator;
 135
 136     simple_allocator->count = 0;
 137     simple_allocator->size = DEFAULT_ALLOCS;
 138     simple_allocator->ptrs = wmem_alloc_array(NULL, void*, DEFAULT_ALLOCS);
 139 }
 140
 141 /*
 142  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 143  *
 144  * Local variables:
 145  * c-basic-offset: 4
 146  * tab-width: 8
 147  * indent-tabs-mode: nil
 148  * End:
 149  *
 150  * vi: set shiftwidth=4 tabstop=8 expandtab:
 151  * :indentSize=4:tabSize=8:noTabs=true:
 152  */