/* * Copyright (c) 2012, 2013 ARM Ltd * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the company may not be used to endorse or promote * products derived from this software without specific prior written * permission. * * THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "nano-malloc.h" /* * Implement either by merging adjacent free memory * or by calling malloc/memcpy */ void * realloc(void * ptr, size_t size) { void * mem; if (ptr == NULL) return malloc(size); if (size == 0) { free(ptr); return NULL; } if (size > MALLOC_MAXSIZE) { errno = ENOMEM; return NULL; } size_t new_size = chunk_size(size); chunk_t *p_to_realloc = ptr_to_chunk(ptr); #if MALLOC_DEBUG __malloc_validate_block(p_to_realloc); #endif size_t old_size = _size(p_to_realloc); /* See if we can avoid allocating new memory * when increasing the size */ if (new_size > old_size) { void *chunk_e = chunk_end(p_to_realloc); MALLOC_LOCK; if (__malloc_grow_chunk(p_to_realloc, new_size)) { /* clear new memory */ memset(chunk_e, '\0', new_size - old_size); /* adjust chunk_t size */ old_size = new_size; } else { chunk_t **p, *r; /* Check to see if there's a chunk_t of free space just past * the current block, merge it in in case that's useful */ for (p = &__malloc_free_list; (r = *p) != NULL; p = &r->next) { if (r == chunk_e) { size_t r_size = _size(r); /* remove R from the free list */ *p = r->next; /* clear the memory from r */ memset(r, '\0', r_size); /* add it's size to our block */ old_size += r_size; _set_size(p_to_realloc, old_size); break; } if (p_to_realloc < r) break; } } MALLOC_UNLOCK; } if (new_size <= old_size) { size_t extra = old_size - new_size; /* If there's enough space left over, split it out * and free it */ if (extra >= MALLOC_MINSIZE) { _set_size(p_to_realloc, new_size); make_free_chunk(chunk_after(p_to_realloc), extra); } return ptr; } /* No short cuts, allocate new memory and copy */ mem = malloc(size); if (!mem) return NULL; memcpy(mem, ptr, old_size - MALLOC_HEAD); free(ptr); return mem; }