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-rw-r--r--src/regex/tre-mem.c163
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diff --git a/src/regex/tre-mem.c b/src/regex/tre-mem.c
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+/*
+ 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 */