Optimized str_repeat() function, it is now 10x faster on 1 byte multipliers

and 5-6x faster on multi-byte multipliers.

diff --git a/ext/standard/string.c b/ext/standard/string.c
index 6d83ee91cdeeed22048036700d07d51b6ae34946..676d3dbcfd0f0e779b37bbeef138274505bf423e 100644 (file)
--- a/ext/standard/string.c
+++ b/ext/standard/string.c
@@ -3537,10 +3537,9 @@ PHPAPI void php_strip_tags(char *rbuf, int len, int *stateptr, char *allow, int
 PHP_FUNCTION(str_repeat)
 {
        zval            **input_str;            /* Input string */
-       zval            **mult;                         /* Multiplier */
-       char             *result;                       /* Resulting string */
-       int                       result_len;           /* Length of the resulting string */
-       int                       i;
+       zval            **mult;                 /* Multiplier */
+       char            *result;                /* Resulting string */
+       int             result_len;             /* Length of the resulting string */
        
        if (ZEND_NUM_ARGS() != 2 || zend_get_parameters_ex(2, &input_str, &mult) == FAILURE) {
                WRONG_PARAM_COUNT;
@@ -3567,12 +3566,24 @@ PHP_FUNCTION(str_repeat)
        result_len = Z_STRLEN_PP(input_str) * Z_LVAL_PP(mult);
        result = (char *)emalloc(result_len + 1);
        
-       /* Copy the input string into the result as many times as necessary */
-       for (i = 0; i < Z_LVAL_PP(mult); i++) {
-               memcpy(result + Z_STRLEN_PP(input_str) * i,
-                          Z_STRVAL_PP(input_str),
-                          Z_STRLEN_PP(input_str));
+       /* Heavy optimization for situations where multiplier is 1 byte long */
+       if (Z_LVAL_PP(mult) == 1) {
+               memset(result, *(Z_STRVAL_PP(input_str)), Z_LVAL_PP(mult)); 
+       } else {
+               char *s, *e, *ee;
+               int l=0;
+               memcpy(result, Z_STRVAL_PP(input_str), Z_STRLEN_PP(input_str));
+               s = result;
+               e = result + Z_STRLEN_PP(input_str);
+               ee = result + result_len;
+               
+               while (e<ee) {
+                       l = (e-s) < (ee-e) ? (e-s) : (ee-e);
+                       memmove(e, s, l);
+                       e += l;
+               }
        }
+
        result[result_len] = '\0';
        
        RETURN_STRINGL(result, result_len, 0);