fix base32 encode/decode

Sources/Uuid.php

@@ -1058,18 +1058,42 @@ protected function adjustTimestamp(): int
 	 * that PHP's base_convert() produces. This is different from basic base32,
 	 * which is specified in RFC 4648, section 6.
 	 *
+	 * This implementation is optimized specifically for UUIDs:
+	 *
 	 * @param string $hex A hexadecimal string.
 	 * @return string A base32hex string.
 	 */
 	protected static function encodeBase32Hex(string $hex): string
 	{
-		$b32 = '';
+		$bin = hex2bin($hex);
+		$alphabet = self::BASE32_HEX;
+		$buffer = 0;
+		$bits = 0;
+		$pos = 0;
+
+		// UUID Base32 is always 26 chars
+		$out = str_repeat('0', 26);
+
+		// UUIDs are always exactly 128 bits (16 bytes).
+		for ($i = 0; $i < 16; $i++) {
+			// Each input byte contributes 8 bits to a buffer.
+			$buffer = ($buffer << 8) | \ord($bin[$i]);
+			$bits += 8;
+
+			// Output characters consume 5 bits at a time.  Remaining bits are carried forward between iterations.
+			while ($bits >= 5) {
+				$bits -= 5;
+
+				$out[$pos++] = $alphabet[($buffer >> $bits) & 31];
+			}
+		}
 
-		foreach (str_split(strrev($hex), 10) as $chunk) {
-			$b32 = str_pad(base_convert(strrev($chunk), 16, 32), 8, '0', STR_PAD_LEFT) . $b32;
+		// UUID Base32 encoding always leaves remaining bits.
+		if ($bits > 0) {
+			$out[$pos] = $alphabet[($buffer << (5 - $bits)) & 31];
 		}
 
-		return ltrim($b32, '0');
+		return $out;
 	}
 
 	/**
@@ -1079,17 +1103,38 @@ protected static function encodeBase32Hex(string $hex): string
 	 * that PHP's base_convert() produces. This is different from basic base32,
 	 * which is specified in RFC 4648, section 6.
 	 *
+	 * This implementation is optimized specifically for UUIDs:
+	 *
 	 * @param string $b32 A base32hex string.
 	 * @return string A hexadecimal string.
 	 */
 	protected static function decodeBase32Hex(string $b32): string
 	{
-		$hex = '';
+		$buffer = 0;
+		$bits = 0;
+		$pos = 0;
+
+		// Decoded UUIDs are always exactly 16 bytes.
+		$out = str_repeat("\0", 16);
 
-		foreach (str_split(strrev($b32), 8) as $chunk) {
-			$hex = str_pad(base_convert(strrev($chunk), 32, 16), 10, '0', STR_PAD_LEFT) . $hex;
+		// UUID Base32 strings are always exactly 26 chars.
+		for ($i = 0; $i < 26; $i++) {
+			$c = \ord($b32[$i]);
+
+			// Convert ASCII to base32 (0-9 => 0-9, a-v => 10-31).
+			$buffer = ($buffer << 5) | ($c <= 57 ? $c - 48 : $c - 87);
+
+			// Each Base32 character contributes 5 bits to a buffer.
+			$bits += 5;
+
+			// Consume output bytes 8 bits at a time.
+			if ($bits >= 8) {
+				$bits -= 8;
+
+				$out[$pos++] = \chr(($buffer >> $bits) & 0xFF);
+			}
 		}
 
-		return ltrim($hex, '0');
+		return bin2hex($out);
 	}
 }