// //////////////////////////////////////////////////////////
// md5.h
// Copyright (c) 2014 Stephan Brumme. All rights reserved.
// see http://create.stephan-brumme.com/disclaimer.html
//

#pragma once

//#include "hash.h"
#include <string>

// define fixed size integer types
#ifdef _MSC_VER
// Windows
typedef unsigned __int8 uint8_t;
typedef unsigned __int32 uint32_t;
typedef unsigned __int64 uint64_t;
#else
// GCC
#include <stdint.h>
#endif

/// compute MD5 hash
/** Usage:
	MD5 md5;
	std::string myHash  = md5("Hello World");     // std::string
	std::string myHash2 = md5("How are you", 11); // arbitrary data, 11 bytes

	// or in a streaming fashion:

	MD5 md5;
	while (more data available)
	  md5.add(pointer to fresh data, number of new bytes);
	std::string myHash3 = md5.getHash();
  */
class MD5  //: public Hash
{
public:
	/// split into 64 byte blocks (=> 512 bits), hash is 16 bytes long
	enum { BlockSize = 512 / 8, HashBytes = 16 };

	/// same as reset()
	MD5();

	/// compute MD5 of a memory block
	std::string operator()(const void* data, size_t numBytes);
	/// compute MD5 of a string, excluding final zero
	std::string operator()(const std::string& text);

	/// add arbitrary number of bytes
	void add(const void* data, size_t numBytes);

	/// return latest hash as 32 hex characters
	std::string getHash();
	/// return latest hash as bytes
	void getHash(unsigned char buffer[HashBytes]);

	/// restart
	void reset();

private:
	/// process 64 bytes
	void processBlock(const void* data);
	/// process everything left in the internal buffer
	void processBuffer();

	/// size of processed data in bytes
	uint64_t m_numBytes;
	/// valid bytes in m_buffer
	size_t m_bufferSize;
	/// bytes not processed yet
	uint8_t m_buffer[BlockSize];

	enum { HashValues = HashBytes / 4 };
	/// hash, stored as integers
	uint32_t m_hash[HashValues];
};
