lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame^] | 1 | /* |
| 2 | This is a version (aka dlmalloc) of malloc/free/realloc written by |
| 3 | Doug Lea and released to the public domain. Use, modify, and |
| 4 | redistribute this code without permission or acknowledgement in any |
| 5 | way you wish. Send questions, comments, complaints, performance |
| 6 | data, etc to dl@cs.oswego.edu |
| 7 | |
| 8 | VERSION 2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee) |
| 9 | |
| 10 | Note: There may be an updated version of this malloc obtainable at |
| 11 | ftp://gee.cs.oswego.edu/pub/misc/malloc.c |
| 12 | Check before installing! |
| 13 | |
| 14 | Hacked up for uClibc by Erik Andersen <andersen@codepoet.org> |
| 15 | */ |
| 16 | |
| 17 | #include "malloc.h" |
| 18 | |
| 19 | |
| 20 | /* ------------------------------ calloc ------------------------------ */ |
| 21 | void* calloc(size_t n_elements, size_t elem_size) |
| 22 | { |
| 23 | mchunkptr p; |
| 24 | unsigned long clearsize; |
| 25 | unsigned long nclears; |
| 26 | size_t size, *d; |
| 27 | void* mem; |
| 28 | |
| 29 | |
| 30 | /* guard vs integer overflow, but allow nmemb |
| 31 | * to fall through and call malloc(0) */ |
| 32 | size = n_elements * elem_size; |
| 33 | if (n_elements && elem_size != (size / n_elements)) { |
| 34 | __set_errno(ENOMEM); |
| 35 | return NULL; |
| 36 | } |
| 37 | |
| 38 | __MALLOC_LOCK; |
| 39 | mem = malloc(size); |
| 40 | if (mem != 0) { |
| 41 | p = mem2chunk(mem); |
| 42 | |
| 43 | if (!chunk_is_mmapped(p)) |
| 44 | { |
| 45 | /* |
| 46 | Unroll clear of <= 36 bytes (72 if 8byte sizes) |
| 47 | We know that contents have an odd number of |
| 48 | size_t-sized words; minimally 3. |
| 49 | */ |
| 50 | |
| 51 | d = (size_t*)mem; |
| 52 | clearsize = chunksize(p) - (sizeof(size_t)); |
| 53 | nclears = clearsize / sizeof(size_t); |
| 54 | assert(nclears >= 3); |
| 55 | |
| 56 | if (nclears > 9) |
| 57 | memset(d, 0, clearsize); |
| 58 | |
| 59 | else { |
| 60 | *(d+0) = 0; |
| 61 | *(d+1) = 0; |
| 62 | *(d+2) = 0; |
| 63 | if (nclears > 4) { |
| 64 | *(d+3) = 0; |
| 65 | *(d+4) = 0; |
| 66 | if (nclears > 6) { |
| 67 | *(d+5) = 0; |
| 68 | *(d+6) = 0; |
| 69 | if (nclears > 8) { |
| 70 | *(d+7) = 0; |
| 71 | *(d+8) = 0; |
| 72 | } |
| 73 | } |
| 74 | } |
| 75 | } |
| 76 | } |
| 77 | #if 0 |
| 78 | else |
| 79 | { |
| 80 | /* Standard unix mmap using /dev/zero clears memory so calloc |
| 81 | * doesn't need to actually zero anything.... |
| 82 | */ |
| 83 | d = (size_t*)mem; |
| 84 | /* Note the additional (sizeof(size_t)) */ |
| 85 | clearsize = chunksize(p) - 2*(sizeof(size_t)); |
| 86 | memset(d, 0, clearsize); |
| 87 | } |
| 88 | #endif |
| 89 | } |
| 90 | __MALLOC_UNLOCK; |
| 91 | return mem; |
| 92 | } |
| 93 | |