unzipfile.cpp

一个使用zlib进行压缩和解压的程序

// UnzipFile.cpp: implementation of the CUnzipFile class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "UnzipFile.h"

#define SIZECENTRALDIRITEM (0x2e)
#define SIZEZIPLOCALHEADER (0x1e)


#ifndef UNZ_BUFSIZE
#define UNZ_BUFSIZE (16384)
#endif

#ifndef UNZ_MAXFILENAMEINZIP
#define UNZ_MAXFILENAMEINZIP (256)
#endif

#define BUFREADCOMMENT (0x400)


#define UNZ_PARAMERROR                  (-102)
#define UNZ_BADZIPFILE                  (-103)
#define UNZ_CRCERROR                    (-105)

unz_s::unz_s()
{
	pfile_in_zip_read = NULL;
}

void unz_s::alloc_pfile_in_zip_read()
{
	if (!pfile_in_zip_read)
		pfile_in_zip_read = new file_in_zip_read_info;
}

void unz_s::free_pfile_in_zip_read()
{
	if (pfile_in_zip_read)
	{
		delete pfile_in_zip_read;
		pfile_in_zip_read = NULL;
	}

}

unz_s::~unz_s()
{
	free_pfile_in_zip_read();
}

file_in_zip_read_info::file_in_zip_read_info()
{
	read_buffer = new char[UNZ_BUFSIZE];
	stream_initialised  = 0;
	pos_local_extrafield = 0;
	crc32 = 0;
	stream.total_out = 0;
}


file_in_zip_read_info::~file_in_zip_read_info()
{
	delete[] read_buffer;
}


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

CUnzipFile::CUnzipFile()
{
	m_bZipFile = false;
	m_pFile = &uf.file;
}


CUnzipFile::CUnzipFile(LPCTSTR lpszPath)
{
	m_bZipFile = false;
	m_pFile = &uf.file;
	Open(lpszPath);
}

//   Close a ZipFile
void CUnzipFile::Close()
{
	if (IsClosed())
		return;

    if (uf.pfile_in_zip_read)
        CloseCurrentFile();
	
	uf.file.Close();
}

//   Close the file in zip opened with OpenCurrentFile
void CUnzipFile::CloseCurrentFile()
{

	if (uf.pfile_in_zip_read == NULL)
		return; // already closed - do not throw an exception

	if (uf.pfile_in_zip_read->rest_read_uncompressed == 0)
	{
		if (uf.pfile_in_zip_read->crc32 != uf.pfile_in_zip_read->crc32_wait)
			ThrowError(UNZ_CRCERROR);
	}

	
	if (uf.pfile_in_zip_read->stream_initialised)
		inflateEnd(&uf.pfile_in_zip_read->stream);

	uf.free_pfile_in_zip_read();

}

/*
  Set the current file of the zipfile to the first file.
*/
void CUnzipFile::GoToFirstFile()
{
	uf.pos_in_central_dir = uf.offset_central_dir;
	uf.num_file = 0;
	unzlocal_GetCurrentFileInfoInternal(uf.cur_file_info,
										uf.cur_file_info_internal,
										NULL,0,NULL,0,NULL,0);
	uf.current_file_ok = 1;
}


/*
  Try locate the file szFileName in the zipfile.

  return value :
  true if the file is found. It becomes the current file.
  false if the file is not found
*/
bool CUnzipFile::LocateFile(CString szFileName, bool bCaseSensitive)
{

    if (szFileName.GetLength() >= UNZ_MAXFILENAMEINZIP)
        ThrowError(UNZ_PARAMERROR);

	if (!uf.current_file_ok)
		return false;

	uLong num_fileSaved = uf.num_file;
	uLong pos_in_central_dirSaved = uf.pos_in_central_dir;

	GoToFirstFile();

	bool res = true;
	while (res)
	{
		char szCurrentFileName[UNZ_MAXFILENAMEINZIP+1];
		GetCurrentFileInfo(NULL, szCurrentFileName, sizeof(szCurrentFileName)-1,
								NULL,0,NULL,0);
		if (StringFileNameCompare(szCurrentFileName, szFileName, bCaseSensitive)==0)
			return true;

		res = GoToNextFile();
	}

	uf.num_file = num_fileSaved ;
	uf.pos_in_central_dir = pos_in_central_dirSaved ;

	return false;
}



/*
  Set the current file of the zipfile to the next file.
  return true if there is no problem
  return false if the actual file was the latest.
*/
bool CUnzipFile::GoToNextFile()
{
	if (!uf.current_file_ok)
		return false;

	if (uf.num_file + 1 == uf.gi.number_entry)
		return false;

	uf.pos_in_central_dir += SIZECENTRALDIRITEM + uf.cur_file_info.size_filename +
			uf.cur_file_info.size_file_extra + uf.cur_file_info.size_file_comment ;

	uf.num_file++;
	unzlocal_GetCurrentFileInfoInternal(uf.cur_file_info,
										uf.cur_file_info_internal,
										NULL,0,NULL,0,NULL,0);
	uf.current_file_ok = 1;
	return true;
}

/*
  Read the local header of the current zipfile
  Check the coherency of the local header and info in the end of central
        directory about this file
  store in *piSizeVar the size of extra info in local header
        (filename and size of extra field data)
*/
void CUnzipFile::unzlocal_CheckCurrentFileCoherencyHeader (uInt & iSizeVar,
													uLong & offset_local_extrafield,
													uLong & size_local_extrafield)
{

	iSizeVar = 0;
	offset_local_extrafield = 0;
	size_local_extrafield = 0;

	uf.file.Seek(uf.cur_file_info_internal.offset_curfile + uf.byte_before_the_zipfile, CFile::begin);

	uLong uMagic;
	unzlocal_getLong(uMagic);
	if (uMagic!=0x04034b50)
		ThrowError(UNZ_BADZIPFILE);

	uLong uData;
	unzlocal_getShort(uData);

// 	if (uData != uf.cur_file_info.version)
// 		ThrowError(UNZ_BADZIPFILE);

	uLong uFlags;
	unzlocal_getShort(uFlags);

	unzlocal_getShort(uData);
	if (uData != uf.cur_file_info.compression_method)
		ThrowError(UNZ_BADZIPFILE);

    if ((uf.cur_file_info.compression_method != 0) &&
                         (uf.cur_file_info.compression_method != Z_DEFLATED))
        ThrowError(UNZ_BADZIPFILE);

	unzlocal_getLong(uData); /* date/time */

	unzlocal_getLong(uData); /* crc */
	if ((uData != uf.cur_file_info.crc) &&
		                      ((uFlags & 8)==0))
		ThrowError(UNZ_BADZIPFILE);

	unzlocal_getLong(uData); /* size compr */

	if ((uData != uf.cur_file_info.compressed_size) &&
							  ((uFlags & 8) == 0))
		ThrowError(UNZ_BADZIPFILE);

	unzlocal_getLong(uData); /* size uncompr */

	if ((uData!=uf.cur_file_info.uncompressed_size) && 
							  ((uFlags & 8)==0))
		ThrowError(UNZ_BADZIPFILE);

	uLong size_filename;
	unzlocal_getShort(size_filename);

	if ((size_filename != uf.cur_file_info.size_filename))
		ThrowError(UNZ_BADZIPFILE);

	iSizeVar = (uInt)size_filename;

	uLong size_extra_field;
	unzlocal_getShort(size_extra_field);

	offset_local_extrafield = uf.cur_file_info_internal.offset_curfile +
									SIZEZIPLOCALHEADER + size_filename;
	size_local_extrafield = (uInt)size_extra_field;

	iSizeVar += (uInt)size_extra_field;

}


//   Open for reading data the current file in the zipfile.
void CUnzipFile::OpenCurrentFile()
{

	ASSERT(uf.current_file_ok);

	if (!uf.current_file_ok)
		ThrowError(UNZ_PARAMERROR);

    if (uf.pfile_in_zip_read)
        CloseCurrentFile();

	uInt iSizeVar;
	uLong offset_local_extrafield;  /* offset of the local extra field */
	uLong  size_local_extrafield;    /* size of the local extra field */

	unzlocal_CheckCurrentFileCoherencyHeader(iSizeVar,
				offset_local_extrafield, size_local_extrafield);

	uf.alloc_pfile_in_zip_read();


	uf.pfile_in_zip_read->offset_local_extrafield = offset_local_extrafield;
	uf.pfile_in_zip_read->size_local_extrafield = size_local_extrafield;

	
	if ((uf.cur_file_info.compression_method!=0) &&
        (uf.cur_file_info.compression_method!=Z_DEFLATED))
		ThrowError(UNZ_BADZIPFILE);


	uf.pfile_in_zip_read->crc32_wait = uf.cur_file_info.crc;
	uf.pfile_in_zip_read->compression_method =
            uf.cur_file_info.compression_method;
	
	uf.pfile_in_zip_read->byte_before_the_zipfile=uf.byte_before_the_zipfile;


	if (uf.cur_file_info.compression_method != 0)
	{
	  uf.pfile_in_zip_read->stream.zalloc = (alloc_func)myalloc;
	  uf.pfile_in_zip_read->stream.zfree = (free_func)myfree;
	  uf.pfile_in_zip_read->stream.opaque = m_bDetectZlibMemoryLeaks ? &m_list : 0;
      
	  int err = inflateInit2(&uf.pfile_in_zip_read->stream, -MAX_WBITS);

	  if (err == Z_OK)
	    uf.pfile_in_zip_read->stream_initialised=1;
	  else 
		  CheckForError(err);
        /* windowBits is passed < 0 to tell that there is no zlib header.
         * Note that in this case inflate *requires* an extra "dummy" byte
         * after the compressed stream in order to complete decompression and
         * return Z_STREAM_END. 
         * In unzip, i don't wait absolutely Z_STREAM_END because I known the 
         * size of both compressed and uncompressed data
         */
	}
	uf.pfile_in_zip_read->rest_read_compressed = 
            uf.cur_file_info.compressed_size ;
	uf.pfile_in_zip_read->rest_read_uncompressed = 
            uf.cur_file_info.uncompressed_size ;

	
	uf.pfile_in_zip_read->pos_in_zipfile = 
            uf.cur_file_info_internal.offset_curfile + SIZEZIPLOCALHEADER + 
			  iSizeVar;
	
	uf.pfile_in_zip_read->stream.avail_in = (uInt)0;

}
/*
  Write info about the ZipFile in the *pglobal_info structure.
  No preparation of the structure is needed
*/
void CUnzipFile::GetGlobalInfo(unz_global_info &global_info)
{
	global_info = uf.gi;
}

void CUnzipFile::GetCurrentFileInfo ( unz_file_info* file_info,
                                         LPSTR szFileName,
										 uLong fileNameBufferSize,
										 void *extraField,
										 uLong extraFieldBufferSize,
										 LPSTR szComment,
										 uLong commentBufferSize)
{

	
	unz_file_info temp;
	if (!file_info)
		file_info = &temp;

	unz_file_info_internal temp1;
	unzlocal_GetCurrentFileInfoInternal(*file_info, temp1, szFileName, fileNameBufferSize,
		extraField, extraFieldBufferSize, szComment, commentBufferSize);
}



/*
  Read bytes from the current file.
  buf contain buffer where data must be copied
  len the size of buf.

  return the number of byte copied if somes bytes are copied
  return 0 if the end of file was reached
*/
int CUnzipFile::ReadCurrentFile(void* buf, UINT len)
{

	if (!uf.pfile_in_zip_read)
		ThrowError(UNZ_PARAMERROR);

	if ((len == 0) || !buf)
		return 0;

	uf.pfile_in_zip_read->stream.next_out = (Bytef*)buf;
	uf.pfile_in_zip_read->stream.avail_out = (uInt)len;
	
	if (len > uf.pfile_in_zip_read->rest_read_uncompressed)
		uf.pfile_in_zip_read->stream.avail_out = 
		  (uInt)uf.pfile_in_zip_read->rest_read_uncompressed;


	uInt iRead = 0;

	while (uf.pfile_in_zip_read->stream.avail_out>0)
	{
		if ((uf.pfile_in_zip_read->stream.avail_in==0) &&
            (uf.pfile_in_zip_read->rest_read_compressed>0))
		{
			uInt uReadThis = UNZ_BUFSIZE;
			if (uf.pfile_in_zip_read->rest_read_compressed<uReadThis)
				uReadThis = (uInt)uf.pfile_in_zip_read->rest_read_compressed;
			if (uReadThis == 0)
				return 0;


			uf.file.Seek(uf.pfile_in_zip_read->pos_in_zipfile + 
				uf.pfile_in_zip_read->byte_before_the_zipfile, CFile::begin);

			uf.file.Read(uf.pfile_in_zip_read->read_buffer, uReadThis);
			uf.pfile_in_zip_read->pos_in_zipfile += uReadThis;

			uf.pfile_in_zip_read->rest_read_compressed-=uReadThis;
			
			uf.pfile_in_zip_read->stream.next_in = 
                (Bytef*)uf.pfile_in_zip_read->read_buffer;
			uf.pfile_in_zip_read->stream.avail_in = (uInt)uReadThis;
		}

		if (uf.pfile_in_zip_read->compression_method==0)
		{
			uInt uDoCopy;
			if (uf.pfile_in_zip_read->stream.avail_out < 
                            uf.pfile_in_zip_read->stream.avail_in)
				uDoCopy = uf.pfile_in_zip_read->stream.avail_out ;
			else
				uDoCopy = uf.pfile_in_zip_read->stream.avail_in ;

			memcpy(uf.pfile_in_zip_read->stream.next_out, 
				uf.pfile_in_zip_read->stream.next_in, uDoCopy);
					
			uf.pfile_in_zip_read->crc32 = crc32(uf.pfile_in_zip_read->crc32,
								uf.pfile_in_zip_read->stream.next_out,