zipcentraldir.cpp

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// ZipCentralDir.cpp: implementation of the CZipCentralDir class.
//
////////////////////////////////////////////////////////////////////////////////
//  Copyright (C) 2000 Tadeusz Dracz.
//  For conditions of distribution and use, see copyright notice in ZipArchive.h
////////////////////////////////////////////////////////////////////////////////


#include "stdafx.h"
#include "ZipCentralDir.h"
#include "ZipArchive.h"

struct CZipAutoHandle
{
	HANDLE m_hFileMap;
	LPVOID m_pFileMap;
	CZipAutoHandle()
	{
		m_hFileMap = NULL;
		m_pFileMap = NULL;
	}
	bool CreateMapping(HANDLE hFile)
	{
		m_hFileMap = CreateFileMapping(hFile, NULL, PAGE_READWRITE,
			0, 0, _T("ZipArchive Mapping File"));
		if (!m_hFileMap)
			return false;
		// Get pointer to memory representing file
		m_pFileMap = MapViewOfFile(m_hFileMap, FILE_MAP_WRITE, 0, 0, 0);
		return (m_pFileMap != NULL);
	}
	void RemoveMapping()
	{
		if (m_pFileMap)
		{
			UnmapViewOfFile(m_pFileMap);
			m_pFileMap = NULL;
		}
		if (m_hFileMap)
		{
			CloseHandle(m_hFileMap);
			m_hFileMap = NULL;
		}
		
	}
	~CZipAutoHandle()
	{
		RemoveMapping();
	}
};

#define ZIPCENTRALDIRSIZE	22

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
char CZipCentralDir::m_gszSignature[] = {0x50, 0x4b, 0x05, 0x06};
CZipCentralDir::CZipCentralDir()
{
	m_bConvertAfterOpen  = true;
	m_bFindFastEnabled = false;
	m_pStorage = NULL;
	m_pOpenedFile = NULL;
	m_iBufferSize = 32768;
	
}

void CZipCentralDir::Init()
{
	m_bOnDisk = false;
	m_uBytesBeforeZip = m_uCentrDirPos = 0;
	m_pOpenedFile = NULL;
	m_pszComment.Release();
}

CZipCentralDir::~CZipCentralDir()
{
	Clear();
}

void CZipCentralDir::Read()
{
	ASSERT(m_pStorage);
	WORD uCommentSize;
	m_uCentrDirPos = Locate();
	m_pStorage->m_pFile->Seek(m_uCentrDirPos, CFile::begin);
	CZipAutoBuffer buf(ZIPCENTRALDIRSIZE);
	DWORD uRead = m_pStorage->m_pFile->Read(buf, ZIPCENTRALDIRSIZE );
	if (uRead != ZIPCENTRALDIRSIZE)
		ThrowError(ZIP_BADZIPFILE);
	memcpy(&m_szSignature,		buf, 4);
	memcpy(&m_uThisDisk,		buf + 4, 2);
	memcpy(&m_uDiskWithCD,		buf + 6, 2);
	memcpy(&m_uDiskEntriesNo,	buf + 8, 2);
	memcpy(&m_uEntriesNumber,	buf + 10, 2);
	memcpy(&m_uSize,			buf + 12, 4);
	memcpy(&m_uOffset,			buf + 16, 4);
	memcpy(&uCommentSize,		buf + 20, 2);
	buf.Release();


	m_pStorage->UpdateSpanMode(m_uThisDisk);
	// if m_uThisDisk is not zero, it is enough to say that it is multi archive
	ASSERT((!m_uThisDisk && (m_uEntriesNumber == m_uDiskEntriesNo) && !m_uDiskWithCD) || m_uThisDisk);

			

	if (!m_pStorage->IsSpanMode() && ((DWORD)m_uCentrDirPos < m_uOffset + m_uSize))
		ThrowError(ZIP_BADZIPFILE);

	if (uCommentSize)
	{
		m_pszComment.Allocate(uCommentSize);
		uRead = m_pStorage->m_pFile->Read(m_pszComment, uCommentSize);
		if (uRead != uCommentSize)
			ThrowError(ZIP_BADZIPFILE);
	}
	
	m_uBytesBeforeZip = m_pStorage->IsSpanMode() ? 0 : m_uCentrDirPos - m_uSize - m_uOffset;

	if ((!m_uSize && m_uEntriesNumber) || (!m_uEntriesNumber && m_uSize))
		ThrowError(ZIP_BADZIPFILE);

	m_bOnDisk = true;
	m_pStorage->ChangeDisk(m_uDiskWithCD);

	if (!m_uSize)
		return;

	ReadHeaders();
}

// return the location of the beginning of the "end" record in the file
DWORD CZipCentralDir::Locate()
{

	// maximum size of end of central dir record
	long uMaxRecordSize = 0xffff + ZIPCENTRALDIRSIZE;
	DWORD uFileSize = m_pStorage->m_pFile->GetLength();

	if ((DWORD)uMaxRecordSize > uFileSize)
		uMaxRecordSize = uFileSize;

	CZipAutoBuffer buf(m_iBufferSize);

	long uPosInFile = 0;
	int uRead = 0;
	// backward reading
	while (uPosInFile < uMaxRecordSize)
	{
		uPosInFile = uRead + m_iBufferSize;
		if (uPosInFile > uMaxRecordSize)
			uPosInFile = uMaxRecordSize;

		int iToRead = uPosInFile - uRead;

		m_pStorage->m_pFile->Seek(-uPosInFile, CFile::end);
		int iActuallyRead = m_pStorage->m_pFile->Read(buf, iToRead);
		if (iActuallyRead != iToRead)
			ThrowError(ZIP_BADZIPFILE);
		// search from the very last bytes to prevent an error if inside archive 
		// there are packed other arhives
		for (int i = iToRead - 4; i >=0 ; i--)
			if (!memcmp((char*)buf + i, m_gszSignature, 4))	
				return uFileSize - (uPosInFile - i);

		uRead += iToRead - 3;

	}
	
	ThrowError(ZIP_CDIR_NOTFOUND);
	return 0;
}

void CZipCentralDir::ThrowError(int err)
{
	AfxThrowZipException(err, m_pStorage->m_pFile->GetFilePath());
}


void CZipCentralDir::ReadHeaders()
{
	m_pStorage->m_pFile->Seek(m_uOffset + m_uBytesBeforeZip, CFile::begin);
	RemoveHeaders();
	for (int i = 0; i < m_uEntriesNumber; i++)
	{
		CZipFileHeader* pHeader = new CZipFileHeader;
		m_headers.Add(pHeader); // bezpo渞ednio nast阷uje w razie wyj箃ku

		if (!pHeader->Read(m_pStorage))
			ThrowError(ZIP_BADZIPFILE);
		ConvertFileName(true, true, pHeader);
	}
	if (m_bFindFastEnabled)
		BuildFindFastArray();

}

// remove all headers from the central dir
void CZipCentralDir::Clear(bool bEverything)
{
	m_pOpenedFile = NULL;
	m_pLocalExtraField.Release();

	if (bEverything)
	{
		RemoveHeaders();
		m_findarray.RemoveAll();
		m_pszComment.Release();
		
	}
}


bool CZipCentralDir::IsValidIndex(WORD uIndex)
{

	bool ret = uIndex < m_headers.GetSize();
#ifdef _DEBUG
	if (!ret)
			TRACE(_T("Not a valid index.\n"));
#endif 
	return ret;
}

// open the file for extracting
void CZipCentralDir::OpenFile(WORD uIndex)
{
	WORD uLocalExtraFieldSize;
	m_pOpenedFile = m_headers[uIndex];
	m_pStorage->ChangeDisk(m_pOpenedFile->m_uDiskStart);
	m_pStorage->m_pFile->Seek(m_pOpenedFile->m_uOffset + m_uBytesBeforeZip, CFile::begin);	
	if (!m_pOpenedFile->ReadLocal(m_pStorage, uLocalExtraFieldSize))
		ThrowError(ZIP_BADZIPFILE);


	m_pLocalExtraField.Release(); // just in case
	if (uLocalExtraFieldSize)
	{
		int iCurrDsk = m_pStorage->GetCurrentDisk();
		m_pLocalExtraField.Allocate(uLocalExtraFieldSize);
		m_pStorage->Read(m_pLocalExtraField, uLocalExtraFieldSize, true);
		if (m_pStorage->GetCurrentDisk() != iCurrDsk)
			ThrowError(ZIP_BADZIPFILE);
	}
	
}

void CZipCentralDir::CloseFile()
{
	if (!m_pOpenedFile)
		return;
	m_pLocalExtraField.Release();
	if (m_pOpenedFile->IsDataDescr())
	{
		CZipAutoBuffer buf(12);
		m_pStorage->Read(buf, 4, false);
		// in span mode, files that are divided between disks have bit 3 of flag set
		// which tell about the presence of the data descriptor after the compressed data
		// This signature may be in the disk spanning archive that is one volume only
		// (it is detected as a non disk spanning archive)
		if (memcmp(buf, CZipStorage::m_gszExtHeaderSignat, 4) != 0) // there is no signature
				m_pStorage->m_pFile->Seek(-4, CFile::current);

		
		m_pStorage->Read(buf, 12, false);
		if (!m_pOpenedFile->CheckCrcAndSizes(buf))
			ThrowError(ZIP_BADZIPFILE);
	}
	m_pOpenedFile = NULL;
}

// add new header using the argument as a template
void CZipCentralDir::AddNewFile(CZipFileHeader & header)
{
	CZipFileHeader* pHeader = new CZipFileHeader(header);
	m_pOpenedFile = pHeader;
	m_headers.Add(pHeader);
	if (m_bFindFastEnabled)
		InsertFindFastElement(pHeader, WORD(m_headers.GetSize() - 1)); // GetSize IS > 0, 'cos we've just added a header
	RemoveFromDisk();
	m_pStorage->m_pFile->SeekToEnd();
}

// called during adding or deleting files; remove the central dir from the disk
void CZipCentralDir::RemoveFromDisk()
{
	if (m_bOnDisk)
	{
		ASSERT(!m_pStorage->IsSpanMode()); // you can't add files to the existing disk span archive or to delete them from it
		m_pStorage->m_pFile->SetLength(m_uBytesBeforeZip + m_uOffset);
		m_bOnDisk = false;
	}
}


void CZipCentralDir::CloseNewFile()
{
	CZipAutoBuffer buf(12 + 4);
	short iToWrite = 0;
	bool bIsSpan = m_pStorage->IsSpanMode() != 0;
	bool bEncrypted = m_pOpenedFile->IsEncrypted();
	if (m_pOpenedFile->IsDataDescr())
	{
		if (bIsSpan || bEncrypted)
		{
			memcpy(buf, m_pStorage->m_gszExtHeaderSignat, 4);
			iToWrite += 4;
		}
	}
	else /*if (!IsSpan)*/
	{
		ASSERT(!bIsSpan && !bEncrypted);
		m_pStorage->Flush();
		m_pStorage->m_pFile->Seek(m_pOpenedFile->m_uOffset + 14, CFile::begin);
		// we don't have to restore the pointer, because before adding a new file, 
		// the pointer is moved to the end
	}

	m_pOpenedFile->GetCrcAndSizes(buf + iToWrite);
	iToWrite += 12;

	// offset set during writting the local header
	m_pOpenedFile->m_uOffset -= m_uBytesBeforeZip;
	
	// write the data descriptor and a disk spanning signature at once
	m_pStorage->Write(buf, iToWrite, true);
	if (!bIsSpan && bEncrypted)
	{
		// write the information to the local header too
		m_pStorage->Flush();
		m_pStorage->m_pFile->Seek(m_pOpenedFile->m_uOffset + 14, CFile::begin);
		m_pStorage->Write(buf + 4, 12, true);
	}

	if (!bIsSpan)
		m_pStorage->Flush();

	m_pOpenedFile = NULL;