Improve base32 package implementation

bakame-php · Mar 22, 2024 · 5c0bde3 · 5c0bde3
1 parent 4ab2451
commit 5c0bde3
Showing 1 changed file with 21 additions and 19 deletions.
diff --git a/src/Base32/Base32.php b/src/Base32/Base32.php
@@ -22,7 +22,6 @@ final class Base32
     private function __construct(string $alphabet, string $padding)
     {
         $normalizeAlphabet = strtoupper($alphabet);
-
         [$this->alphabet, $this->padding] = match (true) {
             1 !== strlen($padding) => throw new ValueError('The padding character must a single character.'),
             "\r" === $padding => throw new ValueError('The padding character can not be the carriage return character.'),
@@ -31,7 +30,7 @@ private function __construct(string $alphabet, string $padding)
             str_contains($alphabet, "\r") => throw new ValueError('The alphabet can not contain the carriage return character.'),
             str_contains($alphabet, "\n") => throw new ValueError('The alphabet can not contain the newline escape sequence.'),
             str_contains($normalizeAlphabet, strtoupper($padding)) => throw new ValueError('The alphabet can not contain the padding character.'),
-            self::ALPHABET_SIZE !== count(array_unique(str_split($normalizeAlphabet))) => throw new ValueError('The alphabet must contain unique characters.'),
+            self::ALPHABET_SIZE !== strlen(count_chars($normalizeAlphabet, 3)) => throw new ValueError('The alphabet must contain unique characters.'), /* @phpstan-ignore-line */
             default => [$alphabet, $padding],
         };
     }
@@ -52,10 +51,12 @@ public function decode(string $encoded, bool $strict = false): string
         }
 
         $alphabet = $this->alphabet;
+        $padding = $this->padding;
         $encoded = str_replace(["\r", "\n"], [''], $encoded);
         if (!$strict) {
             $alphabet = strtoupper($alphabet);
-            $encoded = str_replace(strtoupper($this->padding), $this->padding, strtoupper($encoded));
+            $padding = strtoupper($padding);
+            $encoded = str_replace($padding, $this->padding, strtoupper($encoded));
         }
 
         $remainder = strlen($encoded) % 8;
@@ -64,10 +65,23 @@ public function decode(string $encoded, bool $strict = false): string
                 throw new RuntimeException('The encoded data length is invalid.');
             }
 
-            $encoded .= str_repeat($this->padding, $remainder);
+            $encoded .= str_repeat($padding, $remainder);
+        }
+
+        $inside = rtrim($encoded, $padding);
+        $end = substr($encoded, strlen($inside));
+        if ($strict && !in_array(strlen($end), [3, 4, 6, 0], true)) {
+            throw new RuntimeException('The encoded data contains an invalid padding character length.');
+        }
+
+        if (str_contains($inside, $padding)) {
+            if ($strict) {
+                throw new RuntimeException('The encoded data contains the padding character.');
+            }
+            $encoded = str_replace($padding, '', $inside).$end;
         }
 
-        $characters = $alphabet.$this->padding;
+        $characters = $alphabet.$padding;
         if (strspn($encoded, $characters) !== strlen($encoded)) {
             if ($strict) {
                 throw new RuntimeException('The encoded data contains characters unknown to the alphabet.');
@@ -78,18 +92,6 @@ public function decode(string $encoded, bool $strict = false): string
             }
         }
 
-        $inside = rtrim($encoded, $this->padding);
-        if (str_contains($inside, $this->padding)) {
-            if ($strict) {
-                throw new RuntimeException('The encoded data contains the padding character.');
-            }
-            $encoded = str_replace($this->padding, '', $inside).substr($encoded, strlen($inside));
-        }
-
-        if ($strict && 1 !== preg_match('/^[^'.$this->padding.']+(('.$this->padding.'){3,4}|('.$this->padding.'){6}|'.$this->padding.')?$/', $encoded)) {
-            throw new RuntimeException('The encoded data contains the padding character.');
-        }
-
         $decoded = '';
         $offset = 0;
         $bitLen = 5;
@@ -101,8 +103,8 @@ public function decode(string $encoded, bool $strict = false): string
             if ($bitLen < 8) {
                 $bitLen += 5;
                 $offset++;
-                $pentet = $encoded[$offset] ?? $this->padding;
-                if ($this->padding === $pentet) {
+                $pentet = $encoded[$offset] ?? $padding;
+                if ($padding === $pentet) {
                     $offset = $length;
                 }
                 $val = ($val << 5) + $chars[$pentet];