Working with large strings and arrays (few MB) php does large amount of
reallocs. We can reduce them by preallocating memory when output size
can be predicted.
How about applying such patch? It would be even better if smart strings
expose better allocation api than smart_str_alloc.
Regards,
Wojtek Meler
Index: string.c
===================================================================
RCS file: /repository/php-src/ext/standard/string.c,v
retrieving revision 1.333.2.52.2.3
diff -u -r1.333.2.52.2.3 string.c
--- string.c 1 Jan 2006 13:46:58 -0000 1.333.2.52.2.3
+++ string.c 20 Feb 2006 10:37:13 -0000
@@ -829,12 +829,14 @@
HashPosition pos;
smart_str implstr = {0};
int numelems, i = 0;
+ size_t newlen; //used by smart_str_alloc
numelems = zend_hash_num_elements(Z_ARRVAL_P(arr));
if(numelems == 0) {
RETURN_EMPTY_STRING();
}
+ smart_str_alloc((&implstr),numelems*Z_STRLEN_P(delim),0);
zend_hash_internal_pointer_reset_ex(Z_ARRVAL_P(arr), &pos);
while (zend_hash_get_current_data_ex(Z_ARRVAL_P(arr),
@@ -846,6 +848,8 @@
smart_str_appendl(&implstr, Z_STRVAL_PP(tmp), Z_STRLEN_PP(tmp));
if (++i != numelems) {
smart_str_appendl(&implstr, Z_STRVAL_P(delim), Z_STRLEN_P(delim));
+ newlen = numelems*(implstr.len/i)-implstr.len;
+ smart_str_alloc((&implstr),newlen,0);
}
zend_hash_move_forward_ex(Z_ARRVAL_P(arr), &pos);
}
@@ -1924,6 +1928,10 @@
key = emalloc(maxlen+1);
pos = 0;
+ {
+ size_t newlen;
+ smart_str_alloc((&result),slen,0);
+ }
while (pos < slen) {
if ((pos + maxlen) > slen) {
@@ -2556,6 +2564,9 @@
char *r;
char *end = haystack + length;
smart_str result = {0};
+ size_t newlen; //used by smart_str_alloc
+
+ smart_str_alloc(&result,length,0);
for (p = haystack;
(r = php_memnstr(p, needle, needle_len, end));
--
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