add buffering Randomizer::getBytes

Author: zeriyoshi

ext/random/php_random.h

@@ -176,6 +176,8 @@ typedef struct _php_random_randomizer {
 	const php_random_engine_algo *algo;
 	void *state;
 	bool self_allocate;
+	uint64_t buffer;
+	size_t buffer_size;
 	zend_object std;
 } php_random_randomizer;
 

ext/random/random.c

@@ -801,6 +801,8 @@ static zend_object *php_random_randomizer_new(zend_class_entry *ce) {
 	zend_object_std_init(&randomizer->std, ce);
 	object_properties_init(&randomizer->std, ce);
 
+	randomizer->buffer = 0;
+	randomizer->buffer_size = 0;
 	randomizer->std.handlers = &random_randomizer_object_handlers;
 
 	return &randomizer->std;
@@ -1544,9 +1546,9 @@ PHP_METHOD(Random_Randomizer, getBytes)
 	php_random_randomizer *randomizer = Z_RANDOM_RANDOMIZER_P(ZEND_THIS);
 	zend_string *retval;
 	zend_long length;
-	size_t total_size = 0;
-	size_t required_size;
-	int i;
+	uint64_t result;
+	size_t generated_size;
+	int i = 0;
 
 	ZEND_PARSE_PARAMETERS_START(1, 1)
 		Z_PARAM_LONG(length)
@@ -1558,20 +1560,18 @@ PHP_METHOD(Random_Randomizer, getBytes)
 	}
 
 	retval = zend_string_alloc(length, 0);
-	required_size = length;
-
-	while (total_size < required_size) {
-		uint64_t result;
-		size_t generated_size;
-
-		RANDOM_ENGINE_GENERATE_SIZE(randomizer->algo, randomizer->state, result, generated_size);
 
-		for (i = 0; i < generated_size; i++) {
-			ZSTR_VAL(retval)[total_size++] = (result >> (i * 8) & 0xff);
-			if (total_size >= required_size) {
-				break;
-			}
+	while (i < length) {
+		if (randomizer->buffer_size == 0) {
+			RANDOM_ENGINE_GENERATE_SIZE(randomizer->algo, randomizer->state, result, generated_size);
+			randomizer->buffer = result;
+			randomizer->buffer_size = generated_size;
 		}
+
+		ZSTR_VAL(retval)[i] = randomizer->buffer & 0xff;
+		randomizer->buffer >>= 8;
+		--randomizer->buffer_size;
+		++i;
 	}
 
 	ZSTR_VAL(retval)[length] = '\0';

ext/random/tests/randomizer/get_bytes.phpt

@@ -3,33 +3,46 @@ Random: Randomizer: getBytes
 --FILE--
 <?php
 
-$randomizer = new \Random\Randomizer (
-    new class () implements \Random\Engine
-    {
-        private int $count = 0;
+$engine = new class () implements \Random\Engine {
+    private int $count = 0;
 
-        public function generate(): string
-        {
-            return match ($this->count++) {
-                0 => 'H',
-                1 => 'e',
-                2 => 'l',
-                3 => 'l',
-                4 => 'o',
-                5 => \random_bytes(32), // 128-bit
-                default => \random_bytes(16),
-            };
-        }
+    public function generate(): string
+    {
+        return match ($this->count++) {
+            0 => 'H',
+            1 => 'e',
+            2 => 'l',
+            3 => 'l',
+            4 => 'o',
+            5 => 'Hello',
+            6 => 'Hello',
+            6 => \random_bytes(32), // 128-bit
+            default => \random_bytes(16),
+        };
     }
-);
-
-if ($randomizer->getBytes(5) !== 'Hello') {
-    die('failure');
-}
 
-$randomizer->getBytes(6);
+    public function getCount(): int
+    {
+        return $this->count;
+    }
+};
+$randomizer = new \Random\Randomizer ($engine);
 
-die('success');
+echo $randomizer->getBytes(5). PHP_EOL;
+echo $engine->getCount() . PHP_EOL;
+echo $randomizer->getBytes(5). PHP_EOL;
+echo $engine->getCount() . PHP_EOL;
+echo $randomizer->getBytes(4). PHP_EOL;
+echo $engine->getCount() . PHP_EOL;
+echo $randomizer->getBytes(1). PHP_EOL;
+echo $engine->getCount() . PHP_EOL;
 ?>
 --EXPECTF--
-success
+Hello
+5
+Hello
+6
+Hell
+7
+o
+7