src/PelConvert.php
public static function bytesToSByte($bytes, $offset)
    {
        $n = self::bytesToByte($bytes, $offset);
        if ($n > 127) {
            return $n - 256;
        } else {
            return $n;
        }
    }
public static function bytesToSByte($bytes, $offset)
    {
        $n = self::bytesToByte($bytes, $offset);
        if ($n > 127) {
            return $n - 256;
        } else {
            return $n;
        }
    }
public static function bytesToSByte ( $ bytes , $ offset ) { $ n = self :: bytesToByte ( $ bytes , $ offset ) ; if ( $ n > 127 ) { return $ n - 256 ; } else { return $ n ; } }
Extract a signed byte from bytes.

@param string $bytes
the bytes.

@param integer $offset
the offset. The byte found at the offset will be
returned as an integer. The must be at least one byte available
at offset.

@return integer the signed byte found at offset, e.g., an integer in
the range -128 to 127.
Extract a signed byte from bytes .