[PATCH] optimization for apr_array_copy

[Brian Pane]

apr_array_copy() makes a new array, fills it with null bytes,
and then overwrites it with a copy of the source array.

This patch optimizes away the zero-fill of the part of the
array that's about to be overwritten.

--Brian

Index: srclib/apr/tables/apr_tables.c
===================================================================
RCS file: /home/cvspublic/apr/tables/apr_tables.c,v
retrieving revision 1.19
diff -u -r1.19 apr_tables.c
--- srclib/apr/tables/apr_tables.c      2001/11/26 23:17:09     1.19
+++ srclib/apr/tables/apr_tables.c      2001/12/02 03:56:52
@@ -167,10 +167,14 @@
 APR_DECLARE(apr_array_header_t *) apr_array_copy(apr_pool_t *p,
                                                const apr_array_header_t *arr)
 {
-    apr_array_header_t *res = apr_array_make(p, arr->nalloc, arr->elt_size);
+    apr_array_header_t *res =
+        (apr_array_header_t *) apr_palloc(p, sizeof(apr_array_header_t));
+    make_array_core(res, p, arr->nalloc, arr->elt_size, 0);
 
     memcpy(res->elts, arr->elts, arr->elt_size * arr->nelts);
     res->nelts = arr->nelts;
+    memset(res->elts + res->elt_size * res->nelts, 0,
+           res->elt_size * (res->nalloc - res->nelts));
     return res;
 }