Add a 1-char fastpath to implode() (php#19276)

alexandre-daubois · web-flow · commit 29c7ee4cd462 · 2025-09-10T16:52:31.000+02:00
diff --git a/ext/standard/string.c b/ext/standard/string.c
@@ -1026,7 +1026,11 @@ PHPAPI void php_implode(const zend_string *glue, HashTable *pieces, zval *return
 		}
 
 		cptr -= ZSTR_LEN(glue);
-		memcpy(cptr, ZSTR_VAL(glue), ZSTR_LEN(glue));
+		if (ZSTR_LEN(glue) == 1) {
+			*cptr = ZSTR_VAL(glue)[0];
+		} else {
+			memcpy(cptr, ZSTR_VAL(glue), ZSTR_LEN(glue));
+		}
 	}
 
 	free_alloca(strings, use_heap);

Original file line number	Diff line number	Diff line change
`@@ -1026,7 +1026,11 @@ PHPAPI void php_implode(const zend_string glue, HashTable pieces, zval *return`
`1026`	`1026`	`}`
`1027`	`1027`
`1028`	`1028`	`cptr -= ZSTR_LEN(glue);`
`1029`		`- memcpy(cptr, ZSTR_VAL(glue), ZSTR_LEN(glue));`
	`1029`	`+ if (ZSTR_LEN(glue) == 1) {`
	`1030`	`+ *cptr = ZSTR_VAL(glue)[0];`
	`1031`	`+ } else {`
	`1032`	`+ memcpy(cptr, ZSTR_VAL(glue), ZSTR_LEN(glue));`
	`1033`	`+ }`
`1030`	`1034`	`}`
`1031`	`1035`
`1032`	`1036`	`free_alloca(strings, use_heap);`