// Tif.cpp: implementation of the CTif class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "Tif.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CTif::CTif()
{
	m_nByteOrderFlag=0;	// default order is intel struct 
	m_pTifIFD=NULL;
	m_DibList = NULL;
	m_wIFDNum=0;
}

CTif::~CTif()
{
	FreeMem();
}

BOOL CTif::Load(LPCTSTR szFileName)
{
	register WORD i;

	DWORD dwNextIfd;  // if == 0x0000, ok

	HANDLE hFile;
	CRect r;
	TiffHeader	tiffheader;
	DWORD dwNumOfByteRead;
	WORD wEntryCount;
	WORD wIfdCount;

	hFile=CreateFile(szFileName,GENERIC_READ,FILE_SHARE_READ,NULL,
		OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);
	if(hFile==INVALID_HANDLE_VALUE)
		return FALSE;
	
	if((ReadFile(hFile,&tiffheader,sizeof(TiffHeader),
		&dwNumOfByteRead,NULL))==0) 
	{
		CloseHandle(hFile);
		return FALSE;
	}

	if(tiffheader.nOrderId==0x4D4D) // "MM"
	{
		m_nByteOrderFlag=1;
	}
	else if(tiffheader.nOrderId==0x4949)  // "II"
	{
		m_nByteOrderFlag = 0;
	}
	else 
	{
		CloseHandle(hFile);
		return FALSE;
	}
	
	if(tiffheader.nTiffId!=0x2A)
	{
		reverse(&tiffheader.nTiffId,2);
		if(tiffheader.nTiffId!=0x2A)
		{
			CloseHandle(hFile);
			return FALSE;
		}
	}

	if(m_nByteOrderFlag!=0) // MM
	{
		reverse(&tiffheader.lnFirstIfdOffset,4);
	}
	if(SetFilePointer(hFile,tiffheader.lnFirstIfdOffset,
		NULL,FILE_BEGIN)==0xFFFFFFFF) 
	{
		CloseHandle(hFile);
		return FALSE;
	}
	
	
	// --- 1: compute how many IFDs in this tiff file
	wIfdCount=1;
	
	while(1)
	{
		if((ReadFile(hFile,&wEntryCount,sizeof(WORD),
			&dwNumOfByteRead,NULL))==0) 
		{
			CloseHandle(hFile);
			return FALSE;
		}

		if(m_nByteOrderFlag!=0)
		{
			reverse(&wEntryCount,2);
		}
		long DEL = sizeof(TIFFMARK);
		if(SetFilePointer(hFile,wEntryCount*sizeof(TIFFMARK),
			NULL,FILE_CURRENT)==0xFFFFFFFF)
		{
			CloseHandle(hFile);
			return FALSE;
		}

		if(ReadFile(hFile,&dwNextIfd,sizeof(DWORD),
			&dwNumOfByteRead,NULL)==0)
		{
			CloseHandle(hFile);
			return FALSE;
		}
		if(dwNextIfd != 0)
		{
			wIfdCount++;
			if(m_nByteOrderFlag!=0)
			{
				reverse(&dwNextIfd,4);
			}
			if(SetFilePointer(hFile,dwNextIfd,
				NULL,FILE_BEGIN)==0xFFFFFFFF)
			{
				CloseHandle(hFile);
				return FALSE;
			}
		}
		else
			break;
	}
	
	// --- 2: load every IFDs 
	FreeMem();

	m_wIFDNum=wIfdCount;
	m_pTifIFD=new CTifIFD[m_wIFDNum];

	if(m_pTifIFD==0)
	{
		CloseHandle(hFile);
		return FALSE;
	}

	// begin read IFD
	if(SetFilePointer(hFile,tiffheader.lnFirstIfdOffset,
		NULL,FILE_BEGIN)==0xFFFFFFFF) 
	{
		CloseHandle(hFile);
		return FALSE;
	}

	// create DIB
	if (m_DibList != NULL)
		delete[] m_DibList;

	m_DibList = new CDib[m_wIFDNum];

	//Load all IFDs into memory.
	for(i=0;i<m_wIFDNum;i++)
	{
		if(m_nByteOrderFlag!=0)
		{
			if(!m_pTifIFD[i].LoadIFD(hFile,1))
			{
				CloseHandle(hFile);
				return FALSE;
			}
		}
		else
		{
			if(!m_pTifIFD[i].LoadIFD(hFile,0))
			{
				CloseHandle(hFile);
				return FALSE;
			}
		}

		HDIB hIFDDib = m_pTifIFD[i].UnpackAsDib();
		m_DibList[i].Attach(hIFDDib);
	}	

	CloseHandle(hFile);
		
	return TRUE;
}

void CTif::FreeMem()
{
	WORD i;
	if(m_DibList != NULL)
	{
		delete[] m_DibList;
		m_DibList = NULL;
	}
	if(m_pTifIFD != NULL)
	{
		for(i=0;i<m_wIFDNum;i++)
			m_pTifIFD[i].FreeMem();

		delete[] m_pTifIFD;			
		m_pTifIFD = NULL;
		m_wIFDNum=0;
	}
}