Fixed checksum calculation for ITF14 barcode type

vitkutny · vitkutny · commit acaf80faf87a · 2024-07-17T20:32:27.000+02:00
source: How to calculate a check digit manually https://www.gs1.org/services/how-calculate-check-digit-manually
diff --git a/src/Types/TypeITF14.php b/src/Types/TypeITF14.php
@@ -73,8 +73,8 @@ private function getChecksum(string $code): string
         $total = 0;
 
         for ($charIndex = 0; $charIndex <= (strlen($code) - 1); $charIndex++) {
-            $integerOfChar = intval($code . substr($charIndex, 1));
-            $total += $integerOfChar * (($charIndex === 0 || $charIndex % 2 === 0) ? 3 : 1);
+            $integerOfChar = intval($code[$charIndex]);
+            $total += $integerOfChar * ($charIndex % 2 === 0 ? 3 : 1);
         }
 
         $checksum = 10 - ($total % 10);

Original file line number	Diff line number	Diff line change
`@@ -73,8 +73,8 @@ private function getChecksum(string $code): string`
`73`	`73`	`$total = 0;`
`74`	`74`
`75`	`75`	`for ($charIndex = 0; $charIndex <= (strlen($code) - 1); $charIndex++) {`
`76`		`- $integerOfChar = intval($code . substr($charIndex, 1));`
`77`		`- $total += $integerOfChar * (($charIndex === 0 \|\| $charIndex % 2 === 0) ? 3 : 1);`
	`76`	`+ $integerOfChar = intval($code[$charIndex]);`
	`77`	`+ $total += $integerOfChar * ($charIndex % 2 === 0 ? 3 : 1);`
`78`	`78`	`}`
`79`	`79`
`80`	`80`	`$checksum = 10 - ($total % 10);`