Class CHashWriter

src/hash.h:100–154

A writer stream (for serialization) that computes a 256-bit hash. */

/** 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(Span<const std::byte> src)
    {
        ctx.Write(UCharCast(src.data()), src.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>