[RFC] Add is_representable_as_float() and is_representable_as_int

ext/standard/basic_functions.stub.php

@@ -3700,6 +3700,16 @@ function is_iterable(mixed $value): bool {}
  */
 function is_countable(mixed $value): bool {}
 
+/**
+ * @compile-time-eval
+ */
+function is_representable_as_float(mixed $value): bool {}
+
+/**
+ * @compile-time-eval
+ */
+function is_representable_as_int(mixed $value): bool {}
+
 /* uniqid.c */
 
 #ifdef HAVE_GETTIMEOFDAY

ext/standard/tests/general_functions/is_representable_as_float.phpt

@@ -0,0 +1,245 @@
+--TEST--
+Test is_representable_as_float() function
+--SKIPIF--
+<?php if (PHP_INT_SIZE != 8) die("skip this test is for 64-bit systems only"); ?>
+--FILE--
+<?php
+$representable_as_float = array(
+    0,
+    1,
+    -1,
+    42,
+    -42,
+
+    9007199254740992,  // 2^53
+    -9007199254740992, // -2^53
+    9007199254740991,  // 2^53 - 1
+    -9007199254740991, // -(2^53 - 1)
+
+    // from 2^53 to 2^54, only even numbers are exactly representable
+    9007199254740994,  // 2^53 + 2
+    9007199254740996,  // 2^53 + 4
+    18014398509481984, // 2^54
+    -9007199254740994, // -(2^53 + 2)
+
+    // from 2^54 to 2^55, only multiples of 4 are exactly representable
+    18014398509481988, // 2^54 + 4
+    18014398509481992, // 2^54 + 8
+    36028797018963968, // 2^55
+
+    // from 2^55 to 2^56, only multiples of 8 are exactly representable
+    36028797018963976, // 2^55 + 8
+    36028797018963984, // 2^55 + 16
+    72057594037927936, // 2^56
+
+    // pure powers of two
+    1152921504606846976, // 2^60
+    2305843009213693952, // 2^61
+
+    PHP_INT_MIN,
+
+    0.0,
+    -0.0,
+    1.0,
+    -1.0,
+    3.14,
+    -3.14,
+
+    INF,
+    -INF,
+    NAN,
+
+    2,
+    4,
+    8,
+    16,
+    1024,
+
+    "0",
+    "1",
+    "-1",
+    "42",
+    "0.0",
+    "1.0",
+    "-1.0",
+    "3.14",
+    "-3.14",
+    "1e10",
+    "-1e10",
+    "1.5e-10",
+    "9007199254740992",  // 2^53
+    "-9007199254740992", // -2^53
+
+
+    "9007199254740994",  // 2^53 + 2
+    "18014398509481988", // 2^54 + 4
+    "36028797018963976", // 2^55 + 8
+
+    " 42 ",
+    "\t1.5\n",
+    "\r-3.14\v",
+);
+
+foreach ($representable_as_float as $value) {
+    var_dump(is_representable_as_float($value));
+}
+
+$not_representable_as_float = array(
+    9007199254740993,  // 2^53 + 1
+    -9007199254740993, // -(2^53 + 1)
+    9007199254740995,  // 2^53 + 3
+
+    // odd numbers in 2^53 to 2^54 range
+    9007199254740995,  // 2^53 + 3
+    9007199254740997,  // 2^53 + 5
+    18014398509481985, // 2^54 + 1
+
+    // not multiples of 4 in 2^54 to 2^55 range
+    18014398509481986, // 2^54 + 2
+    18014398509481990, // 2^54 + 6
+    36028797018963970, // 2^55 + 2
+
+    // not multiples of 8 in 2^55 to 2^56 range
+    36028797018963972, // 2^55 + 4
+    36028797018963978, // 2^55 + 10
+    72057594037927940, // 2^56 + 4
+    null,
+    true,
+    false,
+    "",
+    "hello",
+    "123.456.789",
+    "1e400",
+    "-1e400",
+
+    [],
+    [1, 2, 3],
+    new stdClass(),
+
+
+    "9007199254740993",  // 2^53 + 1
+    "18014398509481986", // 2^54 + 2 (not multiple of 4)
+    "36028797018963972", // 2^55 + 4 (not multiple of 8)
+
+    "0x42",
+    "0xFF",
+
+    "0b1010",
+);
+
+$fp = fopen(__FILE__, "r");
+$not_representable_as_float[] = $fp;
+
+foreach ($not_representable_as_float as $value) {
+    var_dump(is_representable_as_float($value));
+}
+
+class TestClass {
+    public function __toString() {
+        return "42";
+    }
+}
+
+$obj = new TestClass();
+var_dump(is_representable_as_float($obj));
+
+class TestClass2 {
+    public function __toString() {
+        return "not_numeric";
+    }
+}
+
+$obj2 = new TestClass2();
+var_dump(is_representable_as_float($obj2));
+
+fclose($fp);
+?>
+--EXPECT--
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(false)
+bool(true)
+bool(false)