1/* 2 tre-mem.c - TRE memory allocator 3 4 Copyright (c) 2001-2009 Ville Laurikari <vl@iki.fi> 5 All rights reserved. 6 7 Redistribution and use in source and binary forms, with or without 8 modification, are permitted provided that the following conditions 9 are met: 10 11 1. Redistributions of source code must retain the above copyright 12 notice, this list of conditions and the following disclaimer. 13 14 2. Redistributions in binary form must reproduce the above copyright 15 notice, this list of conditions and the following disclaimer in the 16 documentation and/or other materials provided with the distribution. 17 18 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS 19 ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30*/ 31 32/* 33 This memory allocator is for allocating small memory blocks efficiently 34 in terms of memory overhead and execution speed. The allocated blocks 35 cannot be freed individually, only all at once. There can be multiple 36 allocators, though. 37*/ 38 39#include <stdlib.h> 40#include <string.h> 41 42#include "tre.h" 43 44/* 45 This memory allocator is for allocating small memory blocks efficiently 46 in terms of memory overhead and execution speed. The allocated blocks 47 cannot be freed individually, only all at once. There can be multiple 48 allocators, though. 49*/ 50 51/* Returns a new memory allocator or NULL if out of memory. */ 52tre_mem_t tre_mem_new_impl(int provided, void* provided_block) { 53 tre_mem_t mem; 54 if (provided) { 55 mem = provided_block; 56 memset(mem, 0, sizeof(*mem)); 57 } else 58 mem = xcalloc(1, sizeof(*mem)); 59 if (mem == NULL) 60 return NULL; 61 return mem; 62} 63 64/* Frees the memory allocator and all memory allocated with it. */ 65void tre_mem_destroy(tre_mem_t mem) { 66 tre_list_t *tmp, *l = mem->blocks; 67 68 while (l != NULL) { 69 xfree(l->data); 70 tmp = l->next; 71 xfree(l); 72 l = tmp; 73 } 74 xfree(mem); 75} 76 77/* Allocates a block of `size' bytes from `mem'. Returns a pointer to the 78 allocated block or NULL if an underlying malloc() failed. */ 79void* tre_mem_alloc_impl(tre_mem_t mem, int provided, void* provided_block, int zero, size_t size) { 80 void* ptr; 81 82 if (mem->failed) { 83 return NULL; 84 } 85 86 if (mem->n < size) { 87 /* We need more memory than is available in the current block. 88 Allocate a new block. */ 89 tre_list_t* l; 90 if (provided) { 91 if (provided_block == NULL) { 92 mem->failed = 1; 93 return NULL; 94 } 95 mem->ptr = provided_block; 96 mem->n = TRE_MEM_BLOCK_SIZE; 97 } else { 98 int block_size; 99 if (size * 8 > TRE_MEM_BLOCK_SIZE) 100 block_size = size * 8; 101 else 102 block_size = TRE_MEM_BLOCK_SIZE; 103 l = xmalloc(sizeof(*l)); 104 if (l == NULL) { 105 mem->failed = 1; 106 return NULL; 107 } 108 l->data = xmalloc(block_size); 109 if (l->data == NULL) { 110 xfree(l); 111 mem->failed = 1; 112 return NULL; 113 } 114 l->next = NULL; 115 if (mem->current != NULL) 116 mem->current->next = l; 117 if (mem->blocks == NULL) 118 mem->blocks = l; 119 mem->current = l; 120 mem->ptr = l->data; 121 mem->n = block_size; 122 } 123 } 124 125 /* Make sure the next pointer will be aligned. */ 126 size += ALIGN(mem->ptr + size, long); 127 128 /* Allocate from current block. */ 129 ptr = mem->ptr; 130 mem->ptr += size; 131 mem->n -= size; 132 133 /* Set to zero if needed. */ 134 if (zero) 135 memset(ptr, 0, size); 136 137 return ptr; 138} 139