12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576 |
- /*
- * libc/stdlib/malloc-zarg/realloc.c -- realloc function
- *
- * Copyright (C) 2002 NEC Corporation
- * Copyright (C) 2002 Miles Bader <miles@gnu.org>
- *
- * This file is subject to the terms and conditions of the GNU Lesser
- * General Public License. See the file COPYING.LIB in the main
- * directory of this archive for more details.
- *
- * Written by Miles Bader <miles@gnu.org>
- */
- #include <stdlib.h>
- #include <string.h>
- #include <sys/mman.h>
- #include "malloc.h"
- #include "heap.h"
- void *realloc (void *mem, size_t new_size)
- {
- if (! mem)
- return malloc (new_size);
- else
- {
- void *base_mem = (size_t *)mem - 1;
- size_t size = *(size_t *)base_mem;
- MALLOC_DEBUG ("realloc: 0x%lx, %d (base = 0x%lx, total_size = %d)\n",
- (long)mem, new_size, (long)base_mem, size);
- if (new_size <= size)
- return mem;
- else
- {
- void *new_mem = 0;
- size_t ext_size = new_size - size;
- void *ext_addr = (char *)base_mem + ext_size;
- if (size >= MALLOC_MMAP_THRESHOLD)
- /* Try to extend this block in place using mmap. */
- {
- ext_size += MALLOC_ROUND_UP_TO_PAGE_SIZE (ext_size);
- new_mem = mmap (ext_addr, ext_size, PROT_READ | PROT_WRITE,
- MAP_FIXED | MAP_SHARED | MAP_ANONYMOUS, 0, 0);
- if (new_mem == MAP_FAILED)
- /* Can't do it. */
- ext_size = 0;
- }
- else
- ext_size = __heap_alloc_at (&__malloc_heap, ext_addr, ext_size);
- if (! ext_size)
- /* Our attempts to extend MEM in place failed, just
- allocate-and-copy. */
- {
- new_mem = malloc (new_size);
- if (new_mem)
- {
- memcpy (new_mem, mem, size);
- free (mem);
- }
- }
- if (new_mem)
- MALLOC_DEBUG (" realloc: returning 0x%lx"
- " (base:0x%lx, total_size:%d)\n",
- (long)new_mem, (long)new_mem - sizeof(size_t), size);
- return new_mem;
- }
- }
- }
|