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authorEric Andersen <andersen@codepoet.org>2003-12-30 10:40:49 +0000
committerEric Andersen <andersen@codepoet.org>2003-12-30 10:40:49 +0000
commit8d532c51318bad2436880ecac972c9dfa3996c9b (patch)
tree821863358734242feb99643e9d66ee9b175ad464 /libc/stdlib/malloc-standard/calloc.c
parent4c9086ee4afde4257a4b4a8f55e05932d1b6acfd (diff)
Rework malloc. The new default implementation is based on dlmalloc from Doug
Lea. It is about 2x faster than the old malloc-930716, and behave itself much better -- it will properly release memory back to the system, and it uses a combination of brk() for small allocations and mmap() for larger allocations. -Erik
Diffstat (limited to 'libc/stdlib/malloc-standard/calloc.c')
-rw-r--r--libc/stdlib/malloc-standard/calloc.c93
1 files changed, 93 insertions, 0 deletions
diff --git a/libc/stdlib/malloc-standard/calloc.c b/libc/stdlib/malloc-standard/calloc.c
new file mode 100644
index 000000000..cff0adab8
--- /dev/null
+++ b/libc/stdlib/malloc-standard/calloc.c
@@ -0,0 +1,93 @@
+/*
+ This is a version (aka dlmalloc) of malloc/free/realloc written by
+ Doug Lea and released to the public domain. Use, modify, and
+ redistribute this code without permission or acknowledgement in any
+ way you wish. Send questions, comments, complaints, performance
+ data, etc to dl@cs.oswego.edu
+
+ VERSION 2.7.2 Sat Aug 17 09:07:30 2002 Doug Lea (dl at gee)
+
+ Note: There may be an updated version of this malloc obtainable at
+ ftp://gee.cs.oswego.edu/pub/misc/malloc.c
+ Check before installing!
+
+ Hacked up for uClibc by Erik Andersen <andersen@codepoet.org>
+*/
+
+#include "malloc.h"
+
+
+/* ------------------------------ calloc ------------------------------ */
+void* calloc(size_t n_elements, size_t elem_size)
+{
+ mchunkptr p;
+ unsigned long clearsize;
+ unsigned long nclears;
+ size_t size, *d;
+ void* mem;
+
+
+ /* guard vs integer overflow, but allow nmemb
+ * to fall through and call malloc(0) */
+ size=lsize * nmemb;
+ if (n_elements && elem_size != (size / n_elements)) {
+ __set_errno(ENOMEM);
+ return NULL;
+ }
+
+ LOCK;
+ mem = malloc(size);
+ if (mem != 0) {
+ p = mem2chunk(mem);
+
+ if (!chunk_is_mmapped(p))
+ {
+ /*
+ Unroll clear of <= 36 bytes (72 if 8byte sizes)
+ We know that contents have an odd number of
+ size_t-sized words; minimally 3.
+ */
+
+ d = (size_t*)mem;
+ clearsize = chunksize(p) - (sizeof(size_t));
+ nclears = clearsize / sizeof(size_t);
+ assert(nclears >= 3);
+
+ if (nclears > 9)
+ memset(d, 0, clearsize);
+
+ else {
+ *(d+0) = 0;
+ *(d+1) = 0;
+ *(d+2) = 0;
+ if (nclears > 4) {
+ *(d+3) = 0;
+ *(d+4) = 0;
+ if (nclears > 6) {
+ *(d+5) = 0;
+ *(d+6) = 0;
+ if (nclears > 8) {
+ *(d+7) = 0;
+ *(d+8) = 0;
+ }
+ }
+ }
+ }
+ }
+#if 0
+ else
+ {
+ /* Standard unix mmap using /dev/zero clears memory so calloc
+ * doesn't need to actually zero anything....
+ */
+ d = (size_t*)mem;
+ /* Note the additional (sizeof(size_t)) */
+ clearsize = chunksize(p) - 2*(sizeof(size_t));
+ memset(d, 0, clearsize);
+ }
+#endif
+ }
+ UNLOCK;
+ return mem;
+}
+