// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2018 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

/**
 * Why base-58 instead of standard base-64 encoding?
 * - Don't want 0OIl characters that look the same in some fonts and
 *      could be used to create visually identical looking data.
 * - A string with non-alphanumeric characters is not as easily accepted as input.
 * - E-mail usually won't line-break if there's no punctuation to break at.
 * - Double-clicking selects the whole string as one word if it's all alphanumeric.
 */
#ifndef BITCOIN_BASE58_H
#define BITCOIN_BASE58_H

#include <string>
#include <vector>
#include <support/allocators/zeroafterfree.h>

/**
 * Encode a byte sequence as a base58-encoded string.
 * pbegin and pend cannot be nullptr, unless both are.
 */
std::string EncodeBase58(const unsigned char* pbegin, const unsigned char* pend);

/**
 * Encode a byte vector as a base58-encoded string
 */
std::string EncodeBase58(const std::vector<unsigned char>& vch);

/**
 * Decode a base58-encoded string (psz) into a byte vector (vchRet).
 * return true if decoding is successful.
 * psz cannot be nullptr.
 */
bool DecodeBase58(const char* psz, std::vector<unsigned char>& vchRet);

/**
 * Decode a base58-encoded string (str) into a byte vector (vchRet).
 * return true if decoding is successful.
 */
bool DecodeBase58(const std::string& str, std::vector<unsigned char>& vchRet);

/**
 * Encode a byte vector into a base58-encoded string, including checksum
 */
std::string EncodeBase58Check(const std::vector<unsigned char>& vchIn);

/**
 * Decode a base58-encoded string (psz) that includes a checksum into a byte
 * vector (vchRet), return true if decoding is successful
 */
bool DecodeBase58Check(const char* psz, std::vector<unsigned char>& vchRet);

/**
 * Decode a base58-encoded string (str) that includes a checksum into a byte
 * vector (vchRet), return true if decoding is successful
 */
bool DecodeBase58Check(const std::string& str, std::vector<unsigned char>& vchRet);

/**
 * Base class for all base58-encoded data
 */
class CBase58Data
{
protected:
    //! the version byte(s)
    std::vector<unsigned char> vchVersion;

    //! the actually encoded data
    typedef std::vector<unsigned char, zero_after_free_allocator<unsigned char> > vector_uchar;
    vector_uchar vchData;

    CBase58Data();
    void SetData(const std::vector<unsigned char> &vchVersionIn, const void* pdata, size_t nSize);
    void SetData(const std::vector<unsigned char> &vchVersionIn, const unsigned char *pbegin, const unsigned char *pend);

public:
    bool SetString(const char* psz, unsigned int nVersionBytes);
    bool SetString(const std::string& str, unsigned int nVersionBytes);
    std::string ToString() const;
    int CompareTo(const CBase58Data& b58) const;

    bool operator==(const CBase58Data& b58) const { return CompareTo(b58) == 0; }
    bool operator<=(const CBase58Data& b58) const { return CompareTo(b58) <= 0; }
    bool operator>=(const CBase58Data& b58) const { return CompareTo(b58) >= 0; }
    bool operator< (const CBase58Data& b58) const { return CompareTo(b58) <  0; }
    bool operator> (const CBase58Data& b58) const { return CompareTo(b58) >  0; }
};

#endif // BITCOIN_BASE58_H