parse a string to bytearray to struct

[cbpetro]

I'm trying to parse a string into individual variables defined by a struct into a byte array. I want to pass the byte array to a com server object and not the string because it's smaller size, correct?

I wrote a function "GetByteArray" to parse the string into the byte array. The problem I have is the byte array does not cast back the floats into my TD struct. I also noticed the size of the byte array written is different than the structure. Why is that?


If there is better approach, please suggest one.

#include "stdafx.h"
#include <stdio.h>
#include <string>

struct TD
{
	short sYear;
	short sMonth;
	short sDay;

        float fVal1;
	float fVal2;
};

void GetByteArray(const std::string& str, unsigned char* bytes)
{
	// get chars 0-3 from str to get string for year 
	std::string strYear = str.substr(0,4);
	short sYear = (short)atoi(strYear.c_str());
	// get chars 5-6 from str to get string for month 
	std::string strMonth = str.substr(5,2);
	short sMonth = (short)atoi(strMonth.c_str());
	// get chars 8-9 from str to get string for day 
	std::string strDay = str.substr(8,2);
	short sDay = (short)atoi(strDay.c_str());
	// get chars 11-17 from str to get string for Val1 
	std::string strVal1 = str.substr(11,7);
	float fVal1 = (float)atof(strVal1.c_str());
	// get chars 19-25 from str to get string for Val2 
	std::string strVal2 = str.substr(19,7);
	float fVal2 = (float)atof(strVal2.c_str());

	size_t i = 0;
	// cast strYear to short and append to byte array
	memcpy(&bytes[i], &sYear, sizeof(short));
	i += sizeof(short);

	// cast strMonth to short and append to byte array
	memcpy(&bytes[i], &sMonth, sizeof(short));
	i += sizeof(short);

	// cast strDay to short and append to byte array
	memcpy(&bytes[i], &sDay, sizeof(short));
	i += sizeof(short);

	// cast strAsk to float and append to byte array
	memcpy(&bytes[i], &fVal1, sizeof(float));
	i += sizeof(float);

	// cast strBid to float and append to byte array
	memcpy(&bytes[i], &fVal2, sizeof(float));
	i += sizeof(float);
}

int main(int argc, char* argv[])
{
	// string to parse
	std::string strData = "2011.06.30,1.40562,1.40559";

	unsigned char MyBytes[sizeof(TD)];
	GetByteArray(strData, MyBytes);

	// i = 14 from GetByteArray
	int i = sizeof(TD); // i = 16 from structure size

	// error here! my floats in td are undefined
	TD* td = (TD*)MyBytes;

	return 0;
}