data_input.cpp

#define _CRT_SECURE_NO_WARNINGS

#include <iostream>

#include "data_input.h"


dataInput::dataInput()
	:mLabelLen(0),
	mImageLen(0),
	mNumLabel(0),
	mNumImage(0),
	mImageStartPos(16),
	mLableStartPos(8)
{
	//todo something
}

dataInput::~dataInput()
{
	mLabelFile.close();
	mImageFile.close();
}


bool dataInput::openLabelFile(const char* url)
{
	mLabelFile.open(url, ios::binary | ios::in);

	if (mLabelFile.is_open())
	{
		int num = 0;
		char temp[4];

		mLabelFile.read(temp, 4);

		if (mLabelFile.gcount() == 4)
		{	
			num = GRB4(temp);
			if (DATA_INPUT_LABEL_FLAG == num)
			{
				mLabelFile.read(temp, 4);

				if (mLabelFile.gcount() == 4)
				{
					mNumLabel = GRB4(temp);
					mLabelLen = 1;
					return true;
				}
				else
				{
					cout << "read label count failed" << endl;
				}
			}
			else
			{
				cout << "this file isn't label file,the flag is:" << num << endl;
			}
		}
	}

	return false;
}

bool dataInput::openImageFile(const char* url)
{
	mImageFile.open(url, ios::binary | ios::in);

	if (mImageFile.is_open())
	{
		int num = 0;

		char temp[4];

		mImageFile.read(temp, 4);

		if (mImageFile.gcount() == 4)
		{
			int flag = DATA_INPUT_IMAGE_FLAG;
			num = GRB4(temp);
			if (DATA_INPUT_IMAGE_FLAG == num)
			{
				mImageFile.read(temp, 4);

				if (mImageFile.gcount() == 4)
				{
					mNumImage = GRB4(temp);

					int width = 0;
					int height = 0;

					mImageFile.read((char*)&width, 4);

					if (mImageFile.gcount() == 4)
					{
						width = GRB4(&width);
						mImageFile.read((char*)&height, 4);

						if (mImageFile.gcount() == 4)
						{
							height = GRB4(&height);
							mImageWidth = width;
							mImageHeight = height;
							mImageLen = width * height;
						}
					}

					return true;
				}
				else
				{
					cout << "read image count failed" << endl;
				}
	


			}
			else
			{
				cout << "this file isn't image file,the flag is:" << num << endl;
			}
		}
	}

	return false;
}

bool dataInput::readIndex(int* label)
{
	if (mLabelFile.is_open() && !mLabelFile.eof())
	{
		mLabelFile.read((char*)label, mLabelLen);
		return mLabelFile.gcount() == mLabelLen;
	}

	return false;
}

bool dataInput::readImage(char imageBuf[])
{
	if (mImageFile.is_open() && !mImageFile.eof())
	{
		mImageFile.read(imageBuf, mImageLen);

		return mImageFile.gcount() == mImageLen;
	}

	return false;
}

bool dataInput::read(int* label, char imageBuf[])
{
	if (readIndex(label))
	{
		return readImage(imageBuf);
	}

	return false;
}

void dataInput::reset()
{
	if (mImageFile.is_open())
	{
		mImageFile.clear();
		mImageFile.seekg(mImageStartPos);
	}

	if (mLabelFile.is_open())
	{
		mLabelFile.clear();
		mLabelFile.seekg(mLableStartPos);
	}
}