ParagonIE_Sodium_File::updateHashWithFile

    public static function updateHashWithFile($hash, $fp, $size = 0)
    {
        /* Type checks: */
        if (PHP_VERSION_ID < 70200) {
            if (!is_resource($hash)) {
                throw new TypeError('Argument 1 must be a resource, ' . gettype($hash) . ' given.');
            }
        } else {
            if (!is_object($hash)) {
                throw new TypeError('Argument 1 must be an object (PHP 7.2+), ' . gettype($hash) . ' given.');
            }
        }

        if (!is_resource($fp)) {
            throw new TypeError('Argument 2 must be a resource, ' . gettype($fp) . ' given.');
        }
        if (!is_int($size)) {
            throw new TypeError('Argument 3 must be an integer, ' . gettype($size) . ' given.');
        }

        /** @var int $originalPosition */
        $originalPosition = self::ftell($fp);

        // Move file pointer to beginning of file
        fseek($fp, 0, SEEK_SET);
        for ($i = 0; $i < $size; $i += self::BUFFER_SIZE) {
            /** @var string|bool $message */
            $message = fread(
                $fp,
                ($size - $i) > self::BUFFER_SIZE
                    ? $size - $i
                    : self::BUFFER_SIZE
            );
            if (!is_string($message)) {
                throw new SodiumException('Unexpected error reading from file.');
            }
            /** @var string $message */
            /** @psalm-suppress InvalidArgument */
            hash_update($hash, $message);
        }
        // Reset file pointer's position
        fseek($fp, $originalPosition, SEEK_SET);
        return $hash;
    }