ParagonIE_Sodium_Core_BLAKE2b::contextToString

    public static function contextToString(SplFixedArray $ctx)
    {
        $str = '';
        /** @var array<int, array<int, int>> $ctxA */
        $ctxA = $ctx[0]->toArray();

        # uint64_t h[8];
        for ($i = 0; $i < 8; ++$i) {
            $str .= self::store32_le($ctxA[$i][1]);
            $str .= self::store32_le($ctxA[$i][0]);
        }

        # uint64_t t[2];
        # uint64_t f[2];
        for ($i = 1; $i < 3; ++$i) {
            $ctxA = $ctx[$i]->toArray();
            $str .= self::store32_le($ctxA[0][1]);
            $str .= self::store32_le($ctxA[0][0]);
            $str .= self::store32_le($ctxA[1][1]);
            $str .= self::store32_le($ctxA[1][0]);
        }

        # uint8_t buf[2 * 128];
        $str .= self::SplFixedArrayToString($ctx[3]);

        /** @var int $ctx4 */
        $ctx4 = (int) $ctx[4];

        # size_t buflen;
        $str .= implode('', array(
            self::intToChr($ctx4 & 0xff),
            self::intToChr(($ctx4 >> 8) & 0xff),
            self::intToChr(($ctx4 >> 16) & 0xff),
            self::intToChr(($ctx4 >> 24) & 0xff),
            self::intToChr(($ctx4 >> 32) & 0xff),
            self::intToChr(($ctx4 >> 40) & 0xff),
            self::intToChr(($ctx4 >> 48) & 0xff),
            self::intToChr(($ctx4 >> 56) & 0xff)
        ));
        # uint8_t last_node;
        return $str . self::intToChr($ctx[5]) . str_repeat("\x00", 23);
    }