Merge pull request #5 from AJenbo/patch-1

src/AssertionsTrait.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace byrokrat\checkdigit;
+
+trait AssertionsTrait
+{
+    /**
+     * Validate number sructure, returns number if structure is valid
+     *
+     * @throws InvalidStructureException If $number is not numerical
+     * @return void
+     */
+    protected function assertNumber(string $number)
+    {
+        if (!ctype_digit($number)) {
+            throw new InvalidStructureException(
+                "Number can only contain numerical characters, found <$number>"
+            );
+        }
+    }
+}

src/Modulo10.php

@@ -9,6 +9,8 @@
  */
 class Modulo10 implements Calculator
 {
+    use AssertionsTrait;
+
     /**
      * Check if the last digit of number is a valid modulo 10 check digit
      */
@@ -24,12 +26,21 @@ public function isValid(string $number): bool
      */
     public function calculateCheckDigit(string $number): string
     {
-        if (!ctype_digit($number)) {
-            throw new InvalidStructureException(
-                "Number can only contain numerical characters, found <$number>"
-            );
+        $this->assertNumber($number);
+
+        $sum = $this->calculateSum($number);
+
+        $ceil = $sum;
+
+        while ($ceil % 10 != 0) {
+            $ceil++;
         }
 
+        return (string)($ceil-$sum);
+    }
+
+    protected function calculateSum(string $number): int
+    {
         $weight = 2;
         $sum = 0;
 
@@ -39,12 +50,6 @@ public function calculateCheckDigit(string $number): string
             $weight = ($weight == 2) ? 1 : 2;
         }
 
-        $ceil = $sum;
-
-        while ($ceil % 10 != 0) {
-            $ceil++;
-        }
-
-        return (string)($ceil-$sum);
+        return $sum;
     }
 }

src/Modulo10Gtin.php

@@ -7,42 +7,16 @@
 /**
  * Modulo10 calculator, variant used for GTIN (EAN, UPC, ISBN-13, JAN and ITF) barcodes
  */
-class Modulo10Gtin implements Calculator
+class Modulo10Gtin extends Modulo10
 {
-    /**
-     * Check if the last digit of number is a valid modulo 10 check digit
-     */
-    public function isValid(string $number): bool
+    protected function calculateSum(string $number): int
     {
-        return substr($number, -1) === $this->calculateCheckDigit(substr($number, 0, -1) ?: '');
-    }
-
-    /**
-     * Calculate the modulo 10 check digit for number
-     *
-     * @throws InvalidStructureException If $number is not numerical
-     */
-    public function calculateCheckDigit(string $number): string
-    {
-        if (!ctype_digit($number)) {
-            throw new InvalidStructureException(
-                "Number can only contain numerical characters, found <$number>"
-            );
-        }
-
-        $weight = 3;
         $sum = 0;
 
         foreach (array_reverse(str_split($number)) as $pos => $digit) {
-            $sum += $digit * ($pos % 2 ? 1 : $weight);
-        }
-
-        $ceil = $sum;
-
-        while ($ceil % 10 != 0) {
-            $ceil++;
+            $sum += $digit * ($pos % 2 ? 1 : 3);
         }
 
-        return (string)($ceil-$sum);
+        return $sum;
     }
 }

src/Modulo11.php

@@ -9,6 +9,8 @@
  */
 class Modulo11 implements Calculator
 {
+    use AssertionsTrait;
+
     /**
      * @var array Map modulo 11 remainder to check digit
      */
@@ -58,9 +60,7 @@ public function isValid(string $number): bool
      */
     public function calculateCheckDigit(string $number): string
     {
-        if (!ctype_digit($number)) {
-            throw new InvalidStructureException("Number must consist of characters 0-9");
-        }
+        $this->assertNumber($number);
 
         $sum = 0;
 

src/Modulo97.php

@@ -9,14 +9,17 @@
  */
 class Modulo97 implements Calculator
 {
+    use AssertionsTrait;
+
     /**
      * Check if the last two digits of number are valid modulo 97 check digits
      *
      * @throws InvalidStructureException If $number is not numerical
      */
     public function isValid(string $number): bool
     {
-        return bcmod($this->readNumber($number), '97') === '1';
+        $this->assertNumber($number);
+        return bcmod($number, '97') === '1';
     }
 
     /**
@@ -26,22 +29,7 @@ public function isValid(string $number): bool
      */
     public function calculateCheckDigit(string $number): string
     {
-        return (string)(98 - bcmod($this->readNumber($number).'00', '97'));
-    }
-
-    /**
-     * Validate number sructure, returns number if structure is valid
-     *
-     * @throws InvalidStructureException If $number is not numerical
-     */
-    private function readNumber(string $number): string
-    {
-        if (!ctype_digit($number)) {
-            throw new InvalidStructureException(
-                "Number can only contain numerical characters, found <$number>"
-            );
-        }
-
-        return $number;
+        $this->assertNumber($number);
+        return (string)(98 - bcmod($number.'00', '97'));
     }
 }