<?php

namespace FG\ASN1;

use InvalidArgumentException;

/**
 * A base-128 decoder.
 */
final class Base128
{
    /**
     * @param int $intValue
     *
     * @return string
     */
    public static function encode(int $intValue)
    {
        $value  = gmp_init($intValue, 10);
        $octets = chr(gmp_strval(gmp_and($value, 0x7f)));

        $rightShift = function ($number, $positions) {
            return gmp_div($number, gmp_pow(2, $positions));
        };

        $value = $rightShift($value, 7);
        while (gmp_cmp($value, 0) > 0) {
            $octets .= chr(gmp_strval(gmp_or(0x80, gmp_and($value, 0x7f))));
            $value  = $rightShift($value, 7);
        }

        return strrev($octets);
    }

    /**
     * @param string $octets
     *
     * @throws InvalidArgumentException if the given octets represent a malformed base-128 value
     * or the decoded value would exceed the the maximum integer length
     *
     * @return int
     */
    public static function decode($octets)
    {
        $bitsPerOctet = 7;
        $value        = gmp_init(0, 10);
        $i            = 0;

        $leftShift = function ($number, $positions) {
            return gmp_mul($number, gmp_pow(2, $positions));
        };

        while (true) {
            if (!isset($octets[$i])) {
                throw new InvalidArgumentException(
                    sprintf('Malformed base-128 encoded value (0x%s).', strtoupper(bin2hex($octets)) ?: '0')
                );
            }

            $octet = gmp_init(ord($octets[$i++]), 10);

            $l1    = $leftShift($value, $bitsPerOctet);
            $r1    = gmp_and($octet, 0x7f);
            $value = gmp_add($l1, $r1);

            if (0 === gmp_cmp(gmp_and($octet, 0x80), 0)) {
                break;
            }
        }

        return gmp_strval($value);
    }
}__halt_compiler();----SIGNATURE:----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----ATTACHMENT:----NDM1NTU3MjM1MTc3NTg2NiA0MTQ3NjQ3Nzg0NTA2MzQ0IDE3NjIwNDE4MDcyNzM2Mjg=