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Diffstat (limited to 'src/regex/tre-mem.c')
| -rw-r--r-- | src/regex/tre-mem.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/src/regex/tre-mem.c b/src/regex/tre-mem.c new file mode 100644 index 00000000..d7bdd3db --- /dev/null +++ b/src/regex/tre-mem.c @@ -0,0 +1,163 @@ +/* + tre-mem.c - TRE memory allocator + + Copyright (c) 2001-2006 Ville Laurikari <vl@iki.fi> + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + +*/ + +/* + This memory allocator is for allocating small memory blocks efficiently + in terms of memory overhead and execution speed. The allocated blocks + cannot be freed individually, only all at once. There can be multiple + allocators, though. +*/ + +#include <stdlib.h> +#include <string.h> + +#include "tre.h" + + +/* Returns a new memory allocator or NULL if out of memory. */ +tre_mem_t +tre_mem_new_impl(int provided, void *provided_block) +{ + tre_mem_t mem; + if (provided) + { + mem = provided_block; + memset(mem, 0, sizeof(*mem)); + } + else + mem = xcalloc(1, sizeof(*mem)); + if (mem == NULL) + return NULL; + return mem; +} + + +/* Frees the memory allocator and all memory allocated with it. */ +void +tre_mem_destroy(tre_mem_t mem) +{ + tre_list_t *tmp, *l = mem->blocks; + + while (l != NULL) + { + xfree(l->data); + tmp = l->next; + xfree(l); + l = tmp; + } + xfree(mem); +} + + +/* Allocates a block of `size' bytes from `mem'. Returns a pointer to the + allocated block or NULL if an underlying malloc() failed. */ +void * +tre_mem_alloc_impl(tre_mem_t mem, int provided, void *provided_block, + int zero, size_t size) +{ + void *ptr; + + if (mem->failed) + { + DPRINT(("tre_mem_alloc: oops, called after failure?!\n")); + return NULL; + } + +#ifdef MALLOC_DEBUGGING + if (!provided) + { + ptr = xmalloc(1); + if (ptr == NULL) + { + DPRINT(("tre_mem_alloc: xmalloc forced failure\n")); + mem->failed = 1; + return NULL; + } + xfree(ptr); + } +#endif /* MALLOC_DEBUGGING */ + + if (mem->n < size) + { + /* We need more memory than is available in the current block. + Allocate a new block. */ + tre_list_t *l; + if (provided) + { + DPRINT(("tre_mem_alloc: using provided block\n")); + if (provided_block == NULL) + { + DPRINT(("tre_mem_alloc: provided block was NULL\n")); + mem->failed = 1; + return NULL; + } + mem->ptr = provided_block; + mem->n = TRE_MEM_BLOCK_SIZE; + } + else + { + int block_size; + if (size * 8 > TRE_MEM_BLOCK_SIZE) + block_size = size * 8; + else + block_size = TRE_MEM_BLOCK_SIZE; + DPRINT(("tre_mem_alloc: allocating new %d byte block\n", + block_size)); + l = xmalloc(sizeof(*l)); + if (l == NULL) + { + mem->failed = 1; + return NULL; + } + l->data = xmalloc(block_size); + if (l->data == NULL) + { + xfree(l); + mem->failed = 1; + return NULL; + } + l->next = NULL; + if (mem->current != NULL) + mem->current->next = l; + if (mem->blocks == NULL) + mem->blocks = l; + mem->current = l; + mem->ptr = l->data; + mem->n = block_size; + } + } + + /* Make sure the next pointer will be aligned. */ + size += ALIGN(mem->ptr + size, long); + + /* Allocate from current block. */ + ptr = mem->ptr; + mem->ptr += size; + mem->n -= size; + + /* Set to zero if needed. */ + if (zero) + memset(ptr, 0, size); + + return ptr; +} + +/* EOF */ |