JuniorHighClient/EvaluationUtil/Base64.cpp

/************************************************
*                        *
* CBase64.cpp                    *
* Base 64 de- and encoding class        *
*                        *
* ============================================  *
*                        *
* This class was written on 28.05.2003        *
* by Jan Raddatz [jan-raddatz@web.de]        *
*                        *
* ============================================  *
*                        *
* Copyright (c) by Jan Raddatz            *
* This class was published @ codeguru.com    *
* 28.05.2003                    *
*                        *
************************************************/
#include "stdafx.h"
#include "Base64.h"


CBase64::CBase64 ()
{
}

unsigned int CBase64::CalculateRecquiredEncodeOutputBufferSize (unsigned int p_InputByteCount)
{
	div_t result = div (p_InputByteCount, 3);

	unsigned int RecquiredBytes = 0;
	if (result.rem == 0)
	{
		// Number of encoded characters
		RecquiredBytes = result.quot * 4;

		// CRLF -> "\r\n" each 76 characters
		result = div (RecquiredBytes, 76);
		RecquiredBytes += result.quot * 2;

		// Terminating null for the Encoded String
		RecquiredBytes += 1;

		return RecquiredBytes;
	}
	else
	{
		// Number of encoded characters
		RecquiredBytes = result.quot * 4 + 4;

		// CRLF -> "\r\n" each 76 characters
		result = div (RecquiredBytes, 76);
		RecquiredBytes += result.quot * 2;

		// Terminating null for the Encoded String
		RecquiredBytes += 1;

		return RecquiredBytes;
	}
}

unsigned int CBase64::CalculateRecquiredDecodeOutputBufferSize (char* p_pInputBufferString)
{
	unsigned int BufferLength = strlen (p_pInputBufferString);

	div_t result = div (BufferLength, 4);

	if (p_pInputBufferString [BufferLength - 1] != '=')
	{
		return result.quot * 3;
	}
	else
	{
		if (p_pInputBufferString [BufferLength - 2] == '=')
		{
			return result.quot * 3 - 2;
		}
		else
		{
			return result.quot * 3 - 1;
		}
	}
}

void CBase64::EncodeByteTriple (char* p_pInputBuffer, unsigned int InputCharacters, char* p_pOutputBuffer)
{
	unsigned int mask = 0xfc000000;
	unsigned int buffer = 0;


	char* temp = (char*) &buffer;
	temp [3] = p_pInputBuffer [0];
	if (InputCharacters > 1)
		temp [2] = p_pInputBuffer [1];
	if (InputCharacters > 2)
		temp [1] = p_pInputBuffer [2];

	switch (InputCharacters)
	{
	case 3:
		{
			p_pOutputBuffer [0] = BASE64_ALPHABET [(buffer & mask) >> 26];
			buffer = buffer << 6;
			p_pOutputBuffer [1] = BASE64_ALPHABET [(buffer & mask) >> 26];
			buffer = buffer << 6;
			p_pOutputBuffer [2] = BASE64_ALPHABET [(buffer & mask) >> 26];
			buffer = buffer << 6;
			p_pOutputBuffer [3] = BASE64_ALPHABET [(buffer & mask) >> 26];
			break;
		}
	case 2:
		{
			p_pOutputBuffer [0] = BASE64_ALPHABET [(buffer & mask) >> 26];
			buffer = buffer << 6;
			p_pOutputBuffer [1] = BASE64_ALPHABET [(buffer & mask) >> 26];
			buffer = buffer << 6;
			p_pOutputBuffer [2] = BASE64_ALPHABET [(buffer & mask) >> 26];
			p_pOutputBuffer [3] = '=';
			break;
		}
	case 1:
		{
			p_pOutputBuffer [0] = BASE64_ALPHABET [(buffer & mask) >> 26];
			buffer = buffer << 6;
			p_pOutputBuffer [1] = BASE64_ALPHABET [(buffer & mask) >> 26];
			p_pOutputBuffer [2] = '=';
			p_pOutputBuffer [3] = '=';
			break;
		}
	}
}

unsigned int CBase64::DecodeByteQuartet (char* p_pInputBuffer, char* p_pOutputBuffer)
{
	unsigned int buffer = 0;

	if (p_pInputBuffer[3] == '=')
	{
		if (p_pInputBuffer[2] == '=')
		{
			buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[0]]) << 6;
			buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[1]]) << 6;
			buffer = buffer << 14;

			char* temp = (char*) &buffer;
			p_pOutputBuffer [0] = temp [3];

			return 1;
		}
		else
		{
			buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[0]]) << 6;
			buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[1]]) << 6;
			buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[2]]) << 6;
			buffer = buffer << 8;

			char* temp = (char*) &buffer;
			p_pOutputBuffer [0] = temp [3];
			p_pOutputBuffer [1] = temp [2];

			return 2;
		}
	}
	else
	{
		buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[0]]) << 6;
		buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[1]]) << 6;
		buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[2]]) << 6;
		buffer = (buffer | BASE64_DEALPHABET [p_pInputBuffer[3]]) << 6; 
		buffer = buffer << 2;

		char* temp = (char*) &buffer;
		p_pOutputBuffer [0] = temp [3];
		p_pOutputBuffer [1] = temp [2];
		p_pOutputBuffer [2] = temp [1];

		return 3;
	}

	return -1;
}

void CBase64::EncodeBuffer(char* p_pInputBuffer, unsigned int p_InputBufferLength, char* p_pOutputBufferString)
{
	unsigned int FinishedByteQuartetsPerLine = 0;
	unsigned int InputBufferIndex  = 0;
	unsigned int OutputBufferIndex = 0;

	memset (p_pOutputBufferString, 0, CalculateRecquiredEncodeOutputBufferSize (p_InputBufferLength));

	while (InputBufferIndex < p_InputBufferLength)
	{
		if (p_InputBufferLength - InputBufferIndex <= 2)
		{
			FinishedByteQuartetsPerLine ++;
			EncodeByteTriple (p_pInputBuffer + InputBufferIndex, p_InputBufferLength - InputBufferIndex, p_pOutputBufferString + OutputBufferIndex);
			break;
		}
		else
		{
			FinishedByteQuartetsPerLine++;
			EncodeByteTriple (p_pInputBuffer + InputBufferIndex, 3, p_pOutputBufferString + OutputBufferIndex);
			InputBufferIndex  += 3;
			OutputBufferIndex += 4;
		}

		if (FinishedByteQuartetsPerLine == 19)
		{
			p_pOutputBufferString [OutputBufferIndex  ] = '\r';
			p_pOutputBufferString [OutputBufferIndex+1] = '\n';
			p_pOutputBufferString += 2;
			FinishedByteQuartetsPerLine = 0;
		}
	}
}

unsigned int CBase64::DecodeBuffer (char* p_pInputBufferString, char* p_pOutputBuffer)
{
	unsigned int InputBufferIndex  = 0;
	unsigned int OutputBufferIndex = 0;
	unsigned int InputBufferLength = strlen (p_pInputBufferString);

	char ByteQuartet [4];

	while (InputBufferIndex < InputBufferLength)
	{
		for (int i = 0; i < 4; i++)
		{
			ByteQuartet [i] = p_pInputBufferString [InputBufferIndex];

			// Ignore all characters except the ones in BASE64_ALPHABET
			if ((ByteQuartet [i] >= 48 && ByteQuartet [i] <=  57) ||
				(ByteQuartet [i] >= 65 && ByteQuartet [i] <=  90) ||
				(ByteQuartet [i] >= 97 && ByteQuartet [i] <= 122) ||
				ByteQuartet [i] == '+' || ByteQuartet [i] == '/' || ByteQuartet [i] == '=')
			{
			}
			else
			{
				// Invalid character
				i--;
			}

			InputBufferIndex++;
		}

		OutputBufferIndex += DecodeByteQuartet (ByteQuartet, p_pOutputBuffer + OutputBufferIndex);
	}

	// OutputBufferIndex gives us the next position of the next decoded character
	// inside our output buffer and thus represents the number of decoded characters
	// in our buffer.
	return OutputBufferIndex;
}

unsigned int CBase64::CreateMatchingEncodingBuffer (unsigned int p_InputByteCount, char** p_ppEncodingBuffer)
{
	unsigned int Size = CalculateRecquiredEncodeOutputBufferSize (p_InputByteCount);
	(*p_ppEncodingBuffer) = (char*) malloc (Size);
	memset (*p_ppEncodingBuffer, 0, Size);
	return Size;
}

unsigned int CBase64::CreateMatchingDecodingBuffer (char* p_pInputBufferString, char** p_ppDecodingBuffer)
{
	unsigned int Size = CalculateRecquiredDecodeOutputBufferSize (p_pInputBufferString);
	(*p_ppDecodingBuffer) = (char*) malloc (Size+1);
	memset (*p_ppDecodingBuffer, 0, Size+1);
	return Size+1;
}

unsigned int CBase64::EncodeFile( CString p_pSourceFileName, CString p_pEncodedFileName )
{
	CFile InputFile;
	CFile OutputFile;

	if (!InputFile.Open (p_pSourceFileName, CFile::modeRead))
		return UNABLE_TO_OPEN_INPUT_FILE;

	if (!OutputFile.Open (p_pEncodedFileName, CFile::modeCreate|CFile::modeWrite))
		return UNABLE_TO_OPEN_OUTPUT_FILE;

	char InputBuffer [19 * 3];
	char* pOutputBuffer;
	CreateMatchingEncodingBuffer (sizeof (InputBuffer), &pOutputBuffer);

	if (pOutputBuffer == 0)
		return UNABLE_TO_CREATE_OUTPUTBUFFER;

	unsigned int ReadBytes = 0;
	while ((ReadBytes = InputFile.Read (InputBuffer, sizeof (InputBuffer))) != 0)
	{
		EncodeBuffer (InputBuffer, ReadBytes, pOutputBuffer);
		OutputFile.Write (pOutputBuffer, strlen (pOutputBuffer));
	}

	OutputFile.Flush ();
	OutputFile.Close ();
	InputFile.Close  ();

	return 0;
}

unsigned int CBase64::DecodeFile( CString p_pSourceFileName, CString p_pDecodedFileName )
{
	CStdioFile    InputFile;
	CFile        OutputFile;

	if (!InputFile.Open (p_pSourceFileName, CFile::modeRead))
		return UNABLE_TO_OPEN_INPUT_FILE;

	if (!OutputFile.Open (p_pDecodedFileName, CFile::modeCreate|CFile::modeWrite))
		return UNABLE_TO_OPEN_OUTPUT_FILE;

	CString InputBuffer;
	char    OutputBuffer[64];

	unsigned int ReadBytes = 0;
	while ((ReadBytes = InputFile.ReadString (InputBuffer)) != 0)
	{
		InputBuffer.Remove ('\r');
		InputBuffer.Remove ('\n');
		throw std::exception();
		//unsigned int DecodedBytes = DecodeBuffer ((LPTSTR) (LPCTSTR) InputBuffer, OutputBuffer);
		//OutputFile.Write (&OutputBuffer [0], DecodedBytes);
	}

	OutputFile.Flush ();
	OutputFile.Close ();
	InputFile.Close  ();

	return 0;
}