hash.h

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

#ifndef DEFI_HASH_H
#define DEFI_HASH_H

#include <attributes.h>
#include <crypto/common.h>
#include <crypto/ripemd160.h>
#include <crypto/sha256.h>
#include <crypto/sha3.h>
#include <prevector.h>
#include <serialize.h>
#include <uint256.h>
#include <version.h>

#include <string>
#include <vector>

typedef uint256 ChainCode;

/** A hasher class for Defi's 256-bit hash (double SHA-256). */
class CHash256 {
private:
    CSHA256 sha;
public:
    static const size_t OUTPUT_SIZE = CSHA256::OUTPUT_SIZE;

    void Finalize(unsigned char hash[OUTPUT_SIZE]) {
        unsigned char buf[CSHA256::OUTPUT_SIZE];
        sha.Finalize(buf);
        sha.Reset().Write(buf, CSHA256::OUTPUT_SIZE).Finalize(hash);
    }

    CHash256& Write(const unsigned char *data, size_t len) {
        sha.Write(data, len);
        return *this;
    }

    CHash256& Reset() {
        sha.Reset();
        return *this;
    }
};

/** A hasher class for Defi's 160-bit hash (SHA-256 + RIPEMD-160). */
class CHash160 {
private:
    CSHA256 sha;
public:
    static const size_t OUTPUT_SIZE = CRIPEMD160::OUTPUT_SIZE;

    void Finalize(unsigned char hash[OUTPUT_SIZE]) {
        unsigned char buf[CSHA256::OUTPUT_SIZE];
        sha.Finalize(buf);
        CRIPEMD160().Write(buf, CSHA256::OUTPUT_SIZE).Finalize(hash);
    }

    CHash160& Write(const unsigned char *data, size_t len) {
        sha.Write(data, len);
        return *this;
    }

    CHash160& Reset() {
        sha.Reset();
        return *this;
    }
};

/** Compute the 256-bit hash of an object. */
template<typename T1>
inline uint256 Hash(const T1 pbegin, const T1 pend)
{
    static const unsigned char pblank[1] = {};
    uint256 result;
    CHash256().Write(pbegin == pend ? pblank : (const unsigned char*)&pbegin[0], (pend - pbegin) * sizeof(pbegin[0]))
              .Finalize((unsigned char*)&result);
    return result;
}

/** Compute the 256-bit hash of the concatenation of two objects. */
template<typename T1, typename T2>
inline uint256 Hash(const T1 p1begin, const T1 p1end,
                    const T2 p2begin, const T2 p2end) {
    static const unsigned char pblank[1] = {};
    uint256 result;
    CHash256().Write(p1begin == p1end ? pblank : (const unsigned char*)&p1begin[0], (p1end - p1begin) * sizeof(p1begin[0]))
              .Write(p2begin == p2end ? pblank : (const unsigned char*)&p2begin[0], (p2end - p2begin) * sizeof(p2begin[0]))
              .Finalize((unsigned char*)&result);
    return result;
}

/** Compute the 256-bit hash of a container. */
template<typename T>
inline uint256 Hash(const T& c)
{
    return Hash(c.begin(), c.end());
}

/** Compute the 256-bit hash of two containers. */
template<typename T>
inline uint256 Hash2(const T& c1, const T& c2)
{
    return Hash(c1.begin(), c1.end(), c2.begin(), c2.end());
}

/** Compute the 160-bit hash an object. */
template<typename T1>
inline uint160 Hash160(const T1 pbegin, const T1 pend)
{
    static unsigned char pblank[1] = {};
    uint160 result;
    CHash160().Write(pbegin == pend ? pblank : (const unsigned char*)&pbegin[0], (pend - pbegin) * sizeof(pbegin[0]))
              .Finalize((unsigned char*)&result);
    return result;
}

/** Compute the 160-bit hash of a vector. */
inline uint160 Hash160(const std::vector<unsigned char>& vch)
{
    return Hash160(vch.begin(), vch.end());
}

/** Compute the 160-bit hash of a vector. */
template<unsigned int N>
inline uint160 Hash160(const prevector<N, unsigned char>& vch)
{
    return Hash160(vch.begin(), vch.end());
}

inline uint160 EthHash160(const std::vector<unsigned char>& vch) {
    std::vector<unsigned char> result;
    sha3_256_safe(vch, result);
    const size_t ADDRESS_OFFSET{12};
    std::vector<unsigned char> output(result.begin() + ADDRESS_OFFSET, result.end());
    std::reverse(output.begin(), output.end());
    return uint160(output);
}

/** A writer stream (for serialization) that computes a 256-bit hash. */
class CHashWriter
{
private:
    CSHA256 ctx;

    const int nType;
    const int nVersion;
public:

    CHashWriter(int nTypeIn, int nVersionIn) : nType(nTypeIn), nVersion(nVersionIn) {}

    int GetType() const { return nType; }
    int GetVersion() const { return nVersion; }

    void write(const char *pch, size_t size) {
        ctx.Write((const unsigned char*)pch, size);
    }

    /** Compute the double-SHA256 hash of all data written to this object.
     *
     * Invalidates this object.
     */
    uint256 GetHash() {
        uint256 result;
        ctx.Finalize(result.begin());
        ctx.Reset().Write(result.begin(), CSHA256::OUTPUT_SIZE).Finalize(result.begin());
        return result;
    }

    /** Compute the SHA256 hash of all data written to this object.
    *
    * Invalidates this object.
    */
    uint256 GetSHA256() {
        uint256 result;
        ctx.Finalize(result.begin());
        return result;
    }

    /**
     * Returns the first 64 bits from the resulting hash.
     */
    inline uint64_t GetCheapHash() {
        uint256 result = GetHash();
        return ReadLE64(result.begin());
    }

    template<typename T>
    CHashWriter& operator<<(const T& obj) {
        // Serialize to this stream
        ::Serialize(*this, obj);
        return (*this);
    }
};

/** Reads data from an underlying stream, while hashing the read data. */
template<typename Source>
class CHashVerifier : public CHashWriter
{
private:
    Source* source;

public:
    explicit CHashVerifier(Source* source_) : CHashWriter(source_->GetType(), source_->GetVersion()), source(source_) {}

    void read(char* pch, size_t nSize)
    {
        source->read(pch, nSize);
        this->write(pch, nSize);
    }

    void ignore(size_t nSize)
    {
        char data[1024];
        while (nSize > 0) {
            size_t now = std::min<size_t>(nSize, 1024);
            read(data, now);
            nSize -= now;
        }
    }

    template<typename T>
    CHashVerifier<Source>& operator>>(T&& obj)
    {
        // Unserialize from this stream
        ::Unserialize(*this, obj);
        return (*this);
    }
};

/** Compute the 256-bit hash of an object's serialization. */
template<typename T>
uint256 SerializeHash(const T& obj, int nType=SER_GETHASH, int nVersion=PROTOCOL_VERSION)
{
    CHashWriter ss(nType, nVersion);
    ss << obj;
    return ss.GetHash();
}

/** Single-SHA256 a 32-byte input (represented as uint256). */
NODISCARD uint256 SHA256Uint256(const uint256& input);

unsigned int MurmurHash3(unsigned int nHashSeed, const uint8_t *vDataToHash, uint32_t vDataSize);

void BIP32Hash(const ChainCode &chainCode, unsigned int nChild, unsigned char header, const unsigned char data[32], unsigned char output[64]);

/** Return a CHashWriter primed for tagged hashes (as specified in BIP 340).
 *
 * The returned object will have SHA256(tag) written to it twice (= 64 bytes).
 * A tagged hash can be computed by feeding the message into this object, and
 * then calling CHashWriter::GetSHA256().
 */
CHashWriter TaggedHash(const std::string& tag);

#endif // DEFI_HASH_H