Minor optimizations to array_keys()/array_values()

array_values():
When the input is an empty array or a packed array with no gaps,
return the original array.

array_keys():
When the input is an empty array, return the original array.
When the input is a packed array with no holes
(and no search key specified), populate the return with
a simple range(0, count($input) - 1)

Author: sgolemon

NEWS

@@ -22,6 +22,7 @@ PHP                                                                        NEWS
     bugs #53838, #61655, #66173, #70925, #72254, etc. (Andrea)
   . Raised minimum supported Windows versions to Windows 7/Server 2008 R2.
     (Anatol)
+  . Implemented minor optimization in array_keys/array_values(). (Sara)
   . Fixed bug #73969 (segfault in debug_print_backtrace). (andrewnester)
   . Added PHP_OS_FAMILY constant to determine on which OS we are. (Jan Altensen)
   . Fixed bug #73994 (arginfo incorrect for unpack). (krakjoe)

ext/standard/array.c

@@ -3938,20 +3938,29 @@ PHP_FUNCTION(array_keys)
 	zend_bool strict = 0;		/* do strict comparison */
 	zend_ulong num_idx;
 	zend_string *str_idx;
+	zend_array *arrval;
+	zend_ulong elem_count;
 
 	ZEND_PARSE_PARAMETERS_START(1, 3)
 		Z_PARAM_ARRAY(input)
 		Z_PARAM_OPTIONAL
 		Z_PARAM_ZVAL(search_value)
 		Z_PARAM_BOOL(strict)
 	ZEND_PARSE_PARAMETERS_END();
+	arrval = Z_ARRVAL_P(input);
+	elem_count = zend_hash_num_elements(arrval);
+
+	/* Base case: empty input */
+	if (!elem_count) {
+		RETURN_ZVAL(input, 1, 0)
+	}
 
 	/* Initialize return array */
 	if (search_value != NULL) {
 		array_init(return_value);
 
 		if (strict) {
-			ZEND_HASH_FOREACH_KEY_VAL_IND(Z_ARRVAL_P(input), num_idx, str_idx, entry) {
+			ZEND_HASH_FOREACH_KEY_VAL_IND(arrval, num_idx, str_idx, entry) {
 				ZVAL_DEREF(entry);
 				if (fast_is_identical_function(search_value, entry)) {
 					if (str_idx) {
@@ -3963,7 +3972,7 @@ PHP_FUNCTION(array_keys)
 				}
 			} ZEND_HASH_FOREACH_END();
 		} else {
-			ZEND_HASH_FOREACH_KEY_VAL_IND(Z_ARRVAL_P(input), num_idx, str_idx, entry) {
+			ZEND_HASH_FOREACH_KEY_VAL_IND(arrval, num_idx, str_idx, entry) {
 				if (fast_equal_check_function(search_value, entry)) {
 					if (str_idx) {
 						ZVAL_STR_COPY(&new_val, str_idx);
@@ -3975,21 +3984,27 @@ PHP_FUNCTION(array_keys)
 			} ZEND_HASH_FOREACH_END();
 		}
 	} else {
-		array_init_size(return_value, zend_hash_num_elements(Z_ARRVAL_P(input)));
-		if (!zend_hash_num_elements(Z_ARRVAL_P(input))) {
-			return;
-		}
+		array_init_size(return_value, elem_count);
 		zend_hash_real_init(Z_ARRVAL_P(return_value), 1);
 		ZEND_HASH_FILL_PACKED(Z_ARRVAL_P(return_value)) {
-			/* Go through input array and add keys to the return array */
-			ZEND_HASH_FOREACH_KEY_VAL_IND(Z_ARRVAL_P(input), num_idx, str_idx, entry) {
-				if (str_idx) {
-					ZVAL_STR_COPY(&new_val, str_idx);
-				} else {
-					ZVAL_LONG(&new_val, num_idx);
+			if (HT_IS_PACKED(arrval) && HT_IS_WITHOUT_HOLES(arrval)) {
+				/* Optimistic case: range(0..n-1) for vector-like packed array */
+				zval new_val;
+				ZVAL_LONG(&new_val, 0);
+				for (; Z_LVAL(new_val) < elem_count; ++Z_LVAL(new_val)) {
+					ZEND_HASH_FILL_ADD(&new_val);
 				}
-				ZEND_HASH_FILL_ADD(&new_val);
-			} ZEND_HASH_FOREACH_END();
+			} else {
+				/* Go through input array and add keys to the return array */
+				ZEND_HASH_FOREACH_KEY_VAL_IND(Z_ARRVAL_P(input), num_idx, str_idx, entry) {
+					if (str_idx) {
+						ZVAL_STR_COPY(&new_val, str_idx);
+					} else {
+						ZVAL_LONG(&new_val, num_idx);
+					}
+					ZEND_HASH_FILL_ADD(&new_val);
+				} ZEND_HASH_FOREACH_END();
+			}
 		} ZEND_HASH_FILL_END();
 	}
 }
@@ -4001,23 +4016,31 @@ PHP_FUNCTION(array_values)
 {
 	zval	 *input,		/* Input array */
 			 *entry;		/* An entry in the input array */
+	zend_array *arrval;
 
 	ZEND_PARSE_PARAMETERS_START(1, 1)
 		Z_PARAM_ARRAY(input)
 	ZEND_PARSE_PARAMETERS_END();
 
-	/* Initialize return array */
-	array_init_size(return_value, zend_hash_num_elements(Z_ARRVAL_P(input)));
+	arrval = Z_ARRVAL_P(input);
 
-	if (!zend_hash_num_elements(Z_ARRVAL_P(input))) {
-		return;
+	/* Return empty input as is */
+	if (!zend_hash_num_elements(arrval)) {
+		RETURN_ZVAL(input, 1, 0);
 	}
 
+	/* Return vector-like packed arrays as-is */
+	if (HT_IS_PACKED(arrval) && HT_IS_WITHOUT_HOLES(arrval)) {
+		RETURN_ZVAL(input, 1, 0);
+	}
+
+	/* Initialize return array */
+	array_init_size(return_value, zend_hash_num_elements(arrval));
 	zend_hash_real_init(Z_ARRVAL_P(return_value), 1);
 
 	/* Go through input array and add values to the return array */
 	ZEND_HASH_FILL_PACKED(Z_ARRVAL_P(return_value)) {
-		ZEND_HASH_FOREACH_VAL(Z_ARRVAL_P(input), entry) {
+		ZEND_HASH_FOREACH_VAL(arrval, entry) {
 			if (UNEXPECTED(Z_ISREF_P(entry) && Z_REFCOUNT_P(entry) == 1)) {
 				entry = Z_REFVAL_P(entry);
 			}

ext/standard/tests/array/packed_001.phpt

@@ -0,0 +1,84 @@
+--TEST--
+array_keys() and array_values() w/ packed optimization
+--FILE--
+<?php
+
+$x = [1,2,3];
+unset($x[1]);
+
+$inputs = [
+  [],
+  [1,2,3],
+  [0=>1, 1=>2, 2=>3],
+  [1=>1, 2=>2, 3=>3],
+  [0=>1, 2=>3],
+  $x,
+];
+
+foreach ($inputs as $input) {
+  print_r(array_keys($input));
+  print_r(array_values($input));
+}
+--EXPECT--
+Array
+(
+)
+Array
+(
+)
+Array
+(
+    [0] => 0
+    [1] => 1
+    [2] => 2
+)
+Array
+(
+    [0] => 1
+    [1] => 2
+    [2] => 3
+)
+Array
+(
+    [0] => 0
+    [1] => 1
+    [2] => 2
+)
+Array
+(
+    [0] => 1
+    [1] => 2
+    [2] => 3
+)
+Array
+(
+    [0] => 1
+    [1] => 2
+    [2] => 3
+)
+Array
+(
+    [0] => 1
+    [1] => 2
+    [2] => 3
+)
+Array
+(
+    [0] => 0
+    [1] => 2
+)
+Array
+(
+    [0] => 1
+    [1] => 3
+)
+Array
+(
+    [0] => 0
+    [1] => 2
+)
+Array
+(
+    [0] => 1
+    [1] => 3
+)