Hashing.h

// Copyright (c) Stefano Cristiano
// SPDX-License-Identifier: MIT
#pragma once
#include "../Common/CompilerMacrosExport.h"
#include "../Common/CompilerMacrosLifetimeBound.h"
#ifndef SC_EXPORT_LIBRARY_HASHING
#define SC_EXPORT_LIBRARY_HASHING 0
#endif
#define SC_HASHING_EXPORT SC_COMPILER_LIBRARY_EXPORT(SC_EXPORT_LIBRARY_HASHING)
 
#include "../Common/PlatformMacrosType.h"
#include "../Common/Span.h"
 
namespace SC
{
 
 
struct Hashing
{
    struct Result
    {
        static constexpr auto MD5_DIGEST_LENGTH    = 16;
        static constexpr auto SHA1_DIGEST_LENGTH   = 20;
        static constexpr auto SHA256_DIGEST_LENGTH = 32;
 
        uint8_t hash[32] = {0};
        size_t  size     = 0;
 
        Span<const uint8_t> toBytesSpan() const SC_LANGUAGE_LIFETIME_BOUND { return {hash, size}; }
    };
    enum Type
    {
        TypeMD5,   
        TypeSHA1,  
        TypeSHA256 
    };
 
    Hashing();
 
    ~Hashing();
 
    Hashing(const Hashing&)            = delete;
    Hashing(Hashing&&)                 = delete;
    Hashing& operator=(const Hashing&) = delete;
    Hashing& operator=(Hashing&&)      = delete;
 
    [[nodiscard]] bool add(Span<const uint8_t> data);
 
    [[nodiscard]] bool getHash(Result& res);
 
    [[nodiscard]] bool setType(Type newType);
 
  private:
#if SC_PLATFORM_APPLE
    alignas(uint64_t) char buffer[104];
#elif SC_PLATFORM_WINDOWS
    alignas(uint64_t) char buffer[16];
    struct CryptoPrivate;
    bool destroyHash();
#elif SC_PLATFORM_LINUX
    int mainSocket = -1; // Not using FileDescriptor just to avoid dependency...
    int hashSocket = -1;
#endif
    bool inited = false;
    Type type   = TypeMD5;
};
} // namespace SC