PHP Base58

<?php
//hex input must be in uppercase, with no leading 0x

define("ADDRESSVERSION","00"); //this is a hex byte

function decodeHex($hex)
{
    $hex=strtoupper($hex);
    $chars="0123456789ABCDEF";
    $return="0";
    for($i=0;$i<strlen($hex);$i++)
    {
        $current=(string)strpos($chars,$hex[$i]);
        $return=(string)bcmul($return,"16",0);
        $return=(string)bcadd($return,$current,0);
    }
    return $return;
}

function encodeHex($dec)
{
    $chars="0123456789ABCDEF";
    $return="";
    while (bccomp($dec,0)==1)
    {
        $dv=(string)bcdiv($dec,"16",0);
        $rem=(integer)bcmod($dec,"16");
        $dec=$dv;
        $return=$return.$chars[$rem];
    }
    return strrev($return);
}

function decodeBase58($base58)
{
    $origbase58=$base58;

    $chars="123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
    $return="0";
    for($i=0;$i<strlen($base58);$i++)
    {
        $current=(string)strpos($chars,$base58[$i]);
        $return=(string)bcmul($return,"58",0);
        $return=(string)bcadd($return,$current,0);
    }

    $return=encodeHex($return);

    //leading zeros
    for($i=0;$i<strlen($origbase58)&&$origbase58[$i]=="1";$i++)
    {
        $return="00".$return;
    }

    if(strlen($return)%2!=0)
    {
        $return="0".$return;
    }

    return $return;
}

function encodeBase58($hex)
{
    if(strlen($hex)%2!=0)
    {
        die("encodeBase58: uneven number of hex characters");
    }
    $orighex=$hex;

    $chars="123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
    $hex=decodeHex($hex);
    $return="";
    while (bccomp($hex,0)==1)
    {
        $dv=(string)bcdiv($hex,"58",0);
        $rem=(integer)bcmod($hex,"58");
        $hex=$dv;
        $return=$return.$chars[$rem];
    }
    $return=strrev($return);

    //leading zeros
    for($i=0;$i<strlen($orighex)&&substr($orighex,$i,2)=="00";$i+=2)
    {
        $return="1".$return;
    }

    return $return;
}

function hash160ToAddress($hash160,$addressversion=ADDRESSVERSION)
{
    $hash160=$addressversion.$hash160;
    $check=pack("H*" , $hash160);
    $check=hash("sha256",hash("sha256",$check,true));
    $check=substr($check,0,8);
    $hash160=strtoupper($hash160.$check);
    return encodeBase58($hash160);
}

function addressToHash160($addr)
{
    $addr=decodeBase58($addr);
    $addr=substr($addr,2,strlen($addr)-10);
    return $addr;
}

function checkAddress($addr,$addressversion=ADDRESSVERSION)
{
    $addr=decodeBase58($addr);
    if(strlen($addr)!=50)
    {
        return false;
    }
    $version=substr($addr,0,2);
    if(hexdec($version)>hexdec($addressversion))
    {
        return false;
    }
    $check=substr($addr,0,strlen($addr)-8);
    $check=pack("H*" , $check);
    $check=strtoupper(hash("sha256",hash("sha256",$check,true)));
    $check=substr($check,0,8);
    return $check==substr($addr,strlen($addr)-8);
}

function hash160($data)
{
    $data=pack("H*" , $data);
    return strtoupper(hash("ripemd160",hash("sha256",$data,true)));
}

function pubKeyToAddress($pubkey)
{
    return hash160ToAddress(hash160($pubkey));
}

function remove0x($string)
{
    if(substr($string,0,2)=="0x"||substr($string,0,2)=="0X")
    {
        $string=substr($string,2);
    }
    return $string;
}

?>