i2pd/libi2pd/Tag.h

#ifndef TAG_H__
#define TAG_H__

/*
* Copyright (c) 2013-2017, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*/

#include <boost/static_assert.hpp>
#include <string.h>
#include <openssl/rand.h>
#include "Base.h"

namespace i2p {
namespace data {

template<size_t sz>
class Tag
{
	BOOST_STATIC_ASSERT_MSG(sz % 8 == 0, "Tag size must be multiple of 8 bytes");

public:

	Tag () = default;
	Tag (const uint8_t * buf) { memcpy (m_Buf, buf, sz); }

	bool operator== (const Tag& other) const { return !memcmp (m_Buf, other.m_Buf, sz); }
	bool operator!= (const Tag& other) const { return !(*this == other); }
	bool operator< (const Tag& other) const { return memcmp (m_Buf, other.m_Buf, sz) < 0; }

	uint8_t * operator()() { return m_Buf; }
	const uint8_t * operator()() const { return m_Buf; }

	operator uint8_t * () { return m_Buf; }
	operator const uint8_t * () const { return m_Buf; }

	const uint8_t * data() const { return m_Buf; }
	const uint64_t * GetLL () const { return ll; }

	bool IsZero () const
	{
		for (size_t i = 0; i < sz/8; ++i)
			if (ll[i]) return false;
		return true;
	}

	void Fill(uint8_t c)
	{
		memset(m_Buf, c, sz);
	}

	void Randomize()
	{
		RAND_bytes(m_Buf, sz);
	}

	std::string ToBase64 () const
	{
		char str[sz*2];
		size_t l = i2p::data::ByteStreamToBase64 (m_Buf, sz, str, sz*2);
		return std::string (str, str + l);
	}

	std::string ToBase32 () const
	{
		char str[sz*2];
		size_t l = i2p::data::ByteStreamToBase32 (m_Buf, sz, str, sz*2);
		return std::string (str, str + l);
	}

	size_t FromBase32 (const std::string& s)
	{
		return i2p::data::Base32ToByteStream (s.c_str (), s.length (), m_Buf, sz);
	}

	size_t FromBase64 (const std::string& s)
	{
		return i2p::data::Base64ToByteStream (s.c_str (), s.length (), m_Buf, sz);
	}

private:

	union // 8 bytes aligned
	{
		uint8_t m_Buf[sz];
		uint64_t ll[sz/8];
	};
};

} // data
} // i2p

namespace std
{
    // hash for std::unordered_map
    template<size_t sz> struct hash<i2p::data::Tag<sz> >
    {
        size_t operator()(const i2p::data::Tag<sz>& s) const 
        {
            return s.GetLL ()[0];
        }
    };    
}

#endif /* TAG_H__ */