From a26ed4ce2002593e42d474460796c7b454e9acca Mon Sep 17 00:00:00 2001
From: Paul Water <p.r.water@setbased.nl>
Date: Sun, 10 May 2020 13:05:36 +0200
Subject: [PATCH] Convert non finite floats 'INF', '-INF', and 'NAN' strings to
 floats.

---
 src/Cast.php           | 34 +++++++++++++++++++++++++++++++---
 test/CastFloatTest.php |  6 ++++++
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/src/Cast.php b/src/Cast.php
index 8802d62..cadec39 100644
--- a/src/Cast.php
+++ b/src/Cast.php
@@ -33,7 +33,7 @@ public static function isManBool($value): bool
 
   //--------------------------------------------------------------------------------------------------------------------
   /**
-   * Returns true if and only if a value is not null and can be casted to a finite float. Otherwise returns false.
+   * Returns true if and only if a value is not null and can be casted to a float. Otherwise returns false.
    *
    * @param mixed $value The value.
    *
@@ -41,7 +41,31 @@ public static function isManBool($value): bool
    */
   public static function isManFiniteFloat($value): bool
   {
-    return (static::isManFloat($value) && is_finite((float)$value));
+    switch (gettype($value))
+    {
+      case 'boolean':
+      case 'integer':
+        return true;
+
+      case 'double':
+        return is_finite($value);
+
+      case 'string':
+        // Reject empty strings.
+        if ($value==='') return false;
+
+        // Reject leading zeros unless they are followed by a decimal point
+        if (strlen($value)>1 && $value[0]==='0' && $value[1]!=='.') return false;
+
+        $filtered = filter_var($value,
+                               FILTER_SANITIZE_NUMBER_FLOAT,
+                               FILTER_FLAG_ALLOW_FRACTION | FILTER_FLAG_ALLOW_SCIENTIFIC);
+
+        return ($filtered===$value);
+
+      default:
+        return false;
+    }
   }
 
   //--------------------------------------------------------------------------------------------------------------------
@@ -72,7 +96,7 @@ public static function isManFloat($value): bool
                                FILTER_SANITIZE_NUMBER_FLOAT,
                                FILTER_FLAG_ALLOW_FRACTION | FILTER_FLAG_ALLOW_SCIENTIFIC);
 
-        return ($filtered===$value);
+        return ($filtered===$value || in_array($value, ['NAN', 'INF', '-INF'], true));
 
       default:
         return false;
@@ -291,6 +315,10 @@ public static function toManFloat($value, ?float $default = null): float
       throw new InvalidCastException('Value can not be converted to float');
     }
 
+    if ($value==='NAN') return NAN;
+    if ($value==='INF') return INF;
+    if ($value==='-INF') return -INF;
+
     return (float)$value;
   }
 
diff --git a/test/CastFloatTest.php b/test/CastFloatTest.php
index e11a84f..6ea3148 100644
--- a/test/CastFloatTest.php
+++ b/test/CastFloatTest.php
@@ -219,6 +219,12 @@ public function validManFloatCases(): array
             ['value'    => -INF,
              'expected' => -INF],
             ['value'    => NAN,
+             'expected' => NAN],
+            ['value'    => 'INF',
+             'expected' => INF],
+            ['value'    => '-INF',
+             'expected' => -INF],
+            ['value'    => 'NAN',
              'expected' => NAN]];
   }