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Minecraft.World/FileInputStream.cpp

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+#include "stdafx.h"
+
+#include "File.h"
+#include "FileInputStream.h"
+
+//Creates a FileInputStream by opening a connection to an actual file, the file named by the File object file in the file system.
+//A new FileDescriptor object is created to represent this file connection.
+//First, if there is a security manager, its checkRead method is called with the path represented by the file argument as its argument.
+//
+//If the named file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading
+//then a FileNotFoundException is thrown.
+//
+//Parameters:
+//file - the file to be opened for reading.
+//Throws:
+//FileNotFoundException - if the file does not exist, is a directory rather than a regular file, or for some other reason cannot be
+//opened for reading.
+//SecurityException - if a security manager exists and its checkRead method denies read access to the file.
+FileInputStream::FileInputStream(const File &file)
+{
+	const char *pchFilename=wstringtofilename(file.getPath());
+#ifdef _UNICODE
+	m_fileHandle = CreateFile(
+		file.getPath().c_str(), // file name
+		GENERIC_READ, // access mode
+		0, // share mode // TODO 4J Stu - Will we need to share file? Probably not but...
+		NULL, // Unused
+		OPEN_EXISTING , // how to create // TODO 4J Stu - Assuming that the file already exists if we are opening to read from it
+		FILE_FLAG_SEQUENTIAL_SCAN, // file attributes
+		NULL // Unsupported
+		);
+#else
+	m_fileHandle = CreateFile(
+		pchFilename, // file name
+		GENERIC_READ, // access mode
+		0, // share mode // TODO 4J Stu - Will we need to share file? Probably not but...
+		NULL, // Unused
+		OPEN_EXISTING , // how to create // TODO 4J Stu - Assuming that the file already exists if we are opening to read from it
+		FILE_FLAG_SEQUENTIAL_SCAN, // file attributes
+		NULL // Unsupported
+		);
+#endif
+
+	if( m_fileHandle == INVALID_HANDLE_VALUE )
+	{
+		// TODO 4J Stu - Any form of error/exception handling
+		//__debugbreak();
+		app.FatalLoadError();
+	}
+}
+
+FileInputStream::~FileInputStream()
+{
+	if( m_fileHandle != INVALID_HANDLE_VALUE )
+		CloseHandle( m_fileHandle );
+}
+
+//Reads a byte of data from this input stream. This method blocks if no input is yet available.
+//Returns:
+//the next byte of data, or -1 if the end of the file is reached.
+int FileInputStream::read()
+{
+	byte byteRead = 0;
+	DWORD numberOfBytesRead;
+
+	BOOL bSuccess = ReadFile(
+		m_fileHandle, // handle to file
+		&byteRead, // data buffer
+		1, // number of bytes to read
+		&numberOfBytesRead, // number of bytes read
+		NULL // overlapped buffer
+		);
+
+	if( bSuccess==FALSE )
+	{
+		// TODO 4J Stu - Some kind of error handling
+		app.FatalLoadError();
+		//return -1;
+	}
+	else if( numberOfBytesRead == 0 )
+	{
+		// File pointer is past the end of the file
+		return -1;
+	}
+
+	return byteRead;
+}
+
+//Reads up to b.length bytes of data from this input stream into an array of bytes. This method blocks until some input is available.
+//Parameters:
+//b - the buffer into which the data is read.
+//Returns:
+//the total number of bytes read into the buffer, or -1 if there is no more data because the end of the file has been reached.
+int FileInputStream::read(byteArray b)
+{
+	DWORD numberOfBytesRead;
+
+	BOOL bSuccess = ReadFile(
+		m_fileHandle, // handle to file
+		b.data, // data buffer
+		b.length, // number of bytes to read
+		&numberOfBytesRead, // number of bytes read
+		NULL // overlapped buffer
+		);
+
+	if( bSuccess==FALSE )
+	{
+		// TODO 4J Stu - Some kind of error handling
+		app.FatalLoadError();
+		//return -1;
+	}
+	else if( numberOfBytesRead == 0 )
+	{
+		// File pointer is past the end of the file
+		return -1;
+	}
+
+	return numberOfBytesRead;
+}
+
+//Reads up to len bytes of data from this input stream into an array of bytes. If len is not zero, the method blocks until some input
+//is available; otherwise, no bytes are read and 0 is returned.
+//Parameters:
+//b - the buffer into which the data is read.
+//off - the start offset in the destination array b
+//len - the maximum number of bytes read.
+//Returns:
+//the total number of bytes read into the buffer, or -1 if there is no more data because the end of the file has been reached.
+int FileInputStream::read(byteArray b, unsigned int offset, unsigned int length)
+{
+	// 4J Stu - We don't want to read any more than the array buffer can hold
+	assert( length <= ( b.length - offset ) );
+
+	DWORD numberOfBytesRead;
+
+	BOOL bSuccess = ReadFile(
+		m_fileHandle, // handle to file
+		&b[offset], // data buffer
+		length, // number of bytes to read
+		&numberOfBytesRead, // number of bytes read
+		NULL // overlapped buffer
+		);
+
+	if( bSuccess==FALSE )
+	{
+		// TODO 4J Stu - Some kind of error handling
+		app.FatalLoadError();
+		//return -1;
+	}
+	else if( numberOfBytesRead == 0 )
+	{
+		// File pointer is past the end of the file
+		return -1;
+	}
+
+	return numberOfBytesRead;
+}
+
+//Closes this file input stream and releases any system resources associated with the stream.
+//If this stream has an associated channel then the channel is closed as well.
+void FileInputStream::close()
+{
+	if(m_fileHandle==INVALID_HANDLE_VALUE)
+	{
+		//printf("\n\nFileInputStream::close - TRYING TO CLOSE AN INVALID FILE HANDLE\n\n");
+		return;
+	}	
+	
+	BOOL result = CloseHandle( m_fileHandle );
+
+	if( result == 0 )
+	{
+		// TODO 4J Stu - Some kind of error handling
+	}
+
+	// Stop the dtor from trying to close it again
+	m_fileHandle = INVALID_HANDLE_VALUE;
+}
+
+
+//Skips n bytes of input from this input stream. Fewer bytes might be skipped if the end of the input stream is reached. The actual number k of bytes to be skipped is equal to the smaller of n and count-pos. The value k is added into pos and k is returned.
+//Overrides:
+//skip in class InputStream
+//Parameters:
+//n - the number of bytes to be skipped.
+//Returns:
+//the actual number of bytes skipped.
+__int64 FileInputStream::skip(__int64 n)
+{
+#ifdef _XBOX
+	LARGE_INTEGER li;
+	li.QuadPart = n;
+	li.LowPart = SetFilePointer(m_fileHandle, li.LowPart, &li.HighPart, FILE_CURRENT);
+
+	if (li.LowPart == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR)
+	{
+		li.QuadPart = 0;
+	}
+
+	return li.QuadPart;
+#else
+	return 0;
+#endif
+}