unzip.cpp

不需要额外的库

				err=UNZ_ERRNO;
		lSeek -= uSizeRead;
	}


	if ((err==UNZ_OK) && (extraField!=NULL))
	{
		uLong uSizeRead ;
		if (file_info.size_file_extra<extraFieldBufferSize)
			uSizeRead = file_info.size_file_extra;
		else
			uSizeRead = extraFieldBufferSize;

		if (lSeek!=0) {
			if (fseek(s->file,lSeek,SEEK_CUR)==0)
				lSeek=0;
			else
				err=UNZ_ERRNO;
		}
		if ((file_info.size_file_extra>0) && (extraFieldBufferSize>0)) {
			if (fread(extraField,(uInt)uSizeRead,1,s->file)!=1)
				err=UNZ_ERRNO;
		}
		lSeek += file_info.size_file_extra - uSizeRead;
	}
	else
		lSeek+=file_info.size_file_extra; 


	if ((err==UNZ_OK) && (szComment!=NULL))
	{
		uLong uSizeRead ;
		if (file_info.size_file_comment<commentBufferSize)
		{
			*(szComment+file_info.size_file_comment)='\0';
			uSizeRead = file_info.size_file_comment;
		}
		else
			uSizeRead = commentBufferSize;

		if (lSeek!=0) {
			if (fseek(s->file,lSeek,SEEK_CUR)==0)
				lSeek=0;
			else
				err=UNZ_ERRNO;
		}
		if ((file_info.size_file_comment>0) && (commentBufferSize>0)) {
			if (fread(szComment,(uInt)uSizeRead,1,s->file)!=1)
				err=UNZ_ERRNO;
		}
		lSeek+=file_info.size_file_comment - uSizeRead;
	}
	else
		lSeek+=file_info.size_file_comment;

	if ((err==UNZ_OK) && (pfile_info!=NULL))
		*pfile_info=file_info;

	if ((err==UNZ_OK) && (pfile_info_internal!=NULL))
		*pfile_info_internal=file_info_internal;

	return err;
}



/*
Write info about the ZipFile in the *pglobal_info structure.
No preparation of the structure is needed
return UNZ_OK if there is no problem.
*/
extern int unzGetCurrentFileInfo (	unzFile file, unz_file_info *pfile_info,
								  char *szFileName, uLong fileNameBufferSize,
								  void *extraField, uLong extraFieldBufferSize,
								  char *szComment, uLong commentBufferSize)
{
	return unzlocal_GetCurrentFileInfoInternal(file,pfile_info,NULL,
		szFileName,fileNameBufferSize,
		extraField,extraFieldBufferSize,
		szComment,commentBufferSize);
}

/*
Set the current file of the zipfile to the first file.
return UNZ_OK if there is no problem
*/
extern int unzGoToFirstFile (unzFile file)
{
	int err=UNZ_OK;
	unz_s* s;
	if (file==NULL)
		return UNZ_PARAMERROR;
	s=(unz_s*)file;
	s->pos_in_central_dir=s->offset_central_dir;
	s->num_file=0;
	err=unzlocal_GetCurrentFileInfoInternal(file,&s->cur_file_info,
		&s->cur_file_info_internal,
		NULL,0,NULL,0,NULL,0);
	s->current_file_ok = (err == UNZ_OK);
	return err;
}


/*
Set the current file of the zipfile to the next file.
return UNZ_OK if there is no problem
return UNZ_END_OF_LIST_OF_FILE if the actual file was the latest.
*/
extern int unzGoToNextFile (unzFile file)
{
	unz_s* s;	
	int err;

	if (file==NULL)
		return UNZ_PARAMERROR;
	s=(unz_s*)file;
	if (!s->current_file_ok)
		return UNZ_END_OF_LIST_OF_FILE;
	if (s->num_file+1==s->gi.number_entry)
		return UNZ_END_OF_LIST_OF_FILE;

	s->pos_in_central_dir += SIZECENTRALDIRITEM + s->cur_file_info.size_filename +
		s->cur_file_info.size_file_extra + s->cur_file_info.size_file_comment ;
	s->num_file++;
	err = unzlocal_GetCurrentFileInfoInternal(file,&s->cur_file_info,
		&s->cur_file_info_internal,
		NULL,0,NULL,0,NULL,0);
	s->current_file_ok = (err == UNZ_OK);
	return err;
}

/*
Get the position of the info of the current file in the zip.
return UNZ_OK if there is no problem
*/
extern int unzGetCurrentFileInfoPosition (unzFile file, unsigned long *pos )
{
	unz_s* s;	

	if (file==NULL)
		return UNZ_PARAMERROR;
	s=(unz_s*)file;

	*pos = s->pos_in_central_dir;
	return UNZ_OK;
}

/*
Set the position of the info of the current file in the zip.
return UNZ_OK if there is no problem
*/
extern int unzSetCurrentFileInfoPosition (unzFile file, unsigned long pos )
{
	unz_s* s;	
	int err;

	if (file==NULL)
		return UNZ_PARAMERROR;
	s=(unz_s*)file;

	s->pos_in_central_dir = pos;
	err = unzlocal_GetCurrentFileInfoInternal(file,&s->cur_file_info,
		&s->cur_file_info_internal,
		NULL,0,NULL,0,NULL,0);
	s->current_file_ok = (err == UNZ_OK);
	return UNZ_OK;
}

/*
Try locate the file szFileName in the zipfile.
For the iCaseSensitivity signification, see unzipStringFileNameCompare

return value :
UNZ_OK if the file is found. It becomes the current file.
UNZ_END_OF_LIST_OF_FILE if the file is not found
*/
extern int unzLocateFile (unzFile file, const char *szFileName, int iCaseSensitivity)
{
	unz_s* s;	
	int err;


	uLong num_fileSaved;
	uLong pos_in_central_dirSaved;


	if (file==NULL)
		return UNZ_PARAMERROR;

	if (strlen(szFileName)>=UNZ_MAXFILENAMEINZIP)
		return UNZ_PARAMERROR;

	s=(unz_s*)file;
	if (!s->current_file_ok)
		return UNZ_END_OF_LIST_OF_FILE;

	num_fileSaved = s->num_file;
	pos_in_central_dirSaved = s->pos_in_central_dir;

	err = unzGoToFirstFile(file);

	while (err == UNZ_OK)
	{
		char szCurrentFileName[UNZ_MAXFILENAMEINZIP+1];
		unzGetCurrentFileInfo(file,NULL,
			szCurrentFileName,sizeof(szCurrentFileName)-1,
			NULL,0,NULL,0);
		if (unzStringFileNameCompare(szCurrentFileName,
			szFileName,iCaseSensitivity)==0)
			return UNZ_OK;
		err = unzGoToNextFile(file);
	}

	s->num_file = num_fileSaved ;
	s->pos_in_central_dir = pos_in_central_dirSaved ;
	return err;
}


/*
Read the static header of the current zipfile
Check the coherency of the static header and info in the end of central
directory about this file
store in *piSizeVar the size of extra info in static header
(filename and size of extra field data)
*/
static int unzlocal_CheckCurrentFileCoherencyHeader (unz_s* s, uInt* piSizeVar,
													 uLong *poffset_local_extrafield,
													 uInt *psize_local_extrafield)
{
	uLong uMagic,uData,uFlags;
	uLong size_filename;
	uLong size_extra_field;
	int err=UNZ_OK;

	*piSizeVar = 0;
	*poffset_local_extrafield = 0;
	*psize_local_extrafield = 0;

	if (fseek(s->file,s->cur_file_info_internal.offset_curfile +
		s->byte_before_the_zipfile,SEEK_SET)!=0)
		return UNZ_ERRNO;


	if (err==UNZ_OK) {
		if (unzlocal_getLong(s->file,&uMagic) != UNZ_OK)
			err=UNZ_ERRNO;
		else if (uMagic!=0x04034b50)
			err=UNZ_BADZIPFILE;
	}
	if (unzlocal_getShort(s->file,&uData) != UNZ_OK)
		err=UNZ_ERRNO;
	/*
	else if ((err==UNZ_OK) && (uData!=s->cur_file_info.wVersion))
	err=UNZ_BADZIPFILE;
	*/
	if (unzlocal_getShort(s->file,&uFlags) != UNZ_OK)
		err=UNZ_ERRNO;

	if (unzlocal_getShort(s->file,&uData) != UNZ_OK)
		err=UNZ_ERRNO;
	else if ((err==UNZ_OK) && (uData!=s->cur_file_info.compression_method))
		err=UNZ_BADZIPFILE;

	if ((err==UNZ_OK) && (s->cur_file_info.compression_method!=0) &&
		(s->cur_file_info.compression_method!=Z_DEFLATED))
		err=UNZ_BADZIPFILE;

	if (unzlocal_getLong(s->file,&uData) != UNZ_OK) /* date/time */
		err=UNZ_ERRNO;

	if (unzlocal_getLong(s->file,&uData) != UNZ_OK) /* crc */
		err=UNZ_ERRNO;
	else if ((err==UNZ_OK) && (uData!=s->cur_file_info.crc) &&
		((uFlags & 8)==0))
		err=UNZ_BADZIPFILE;

	if (unzlocal_getLong(s->file,&uData) != UNZ_OK) /* size compr */
		err=UNZ_ERRNO;
	else if ((err==UNZ_OK) && (uData!=s->cur_file_info.compressed_size) &&
		((uFlags & 8)==0))
		err=UNZ_BADZIPFILE;

	if (unzlocal_getLong(s->file,&uData) != UNZ_OK) /* size uncompr */
		err=UNZ_ERRNO;
	else if ((err==UNZ_OK) && (uData!=s->cur_file_info.uncompressed_size) && 
		((uFlags & 8)==0))
		err=UNZ_BADZIPFILE;


	if (unzlocal_getShort(s->file,&size_filename) != UNZ_OK)
		err=UNZ_ERRNO;
	else if ((err==UNZ_OK) && (size_filename!=s->cur_file_info.size_filename))
		err=UNZ_BADZIPFILE;

	*piSizeVar += (uInt)size_filename;

	if (unzlocal_getShort(s->file,&size_extra_field) != UNZ_OK)
		err=UNZ_ERRNO;
	*poffset_local_extrafield= s->cur_file_info_internal.offset_curfile +
		SIZEZIPLOCALHEADER + size_filename;
	*psize_local_extrafield = (uInt)size_extra_field;

	*piSizeVar += (uInt)size_extra_field;

	return err;
}

/*
Open for reading data the current file in the zipfile.
If there is no error and the file is opened, the return value is UNZ_OK.
*/
extern int unzOpenCurrentFile (unzFile file)
{
	int err=UNZ_OK;
	int Store;
	uInt iSizeVar;
	unz_s* s;
	file_in_zip_read_info_s* pfile_in_zip_read_info;
	uLong offset_local_extrafield;  /* offset of the static extra field */
	uInt  size_local_extrafield;    /* size of the static extra field */

	if (file==NULL)
		return UNZ_PARAMERROR;
	s=(unz_s*)file;
	if (!s->current_file_ok)
		return UNZ_PARAMERROR;

	if (s->pfile_in_zip_read != NULL)
		unzCloseCurrentFile(file);

	if (unzlocal_CheckCurrentFileCoherencyHeader(s,&iSizeVar,
		&offset_local_extrafield,&size_local_extrafield)!=UNZ_OK)
		return UNZ_BADZIPFILE;

	pfile_in_zip_read_info = (file_in_zip_read_info_s*)
		ALLOC(sizeof(file_in_zip_read_info_s));
	if (pfile_in_zip_read_info==NULL)
		return UNZ_INTERNALERROR;

	pfile_in_zip_read_info->read_buffer=(char*)ALLOC(UNZ_BUFSIZE);
	pfile_in_zip_read_info->offset_local_extrafield = offset_local_extrafield;
	pfile_in_zip_read_info->size_local_extrafield = size_local_extrafield;
	pfile_in_zip_read_info->pos_local_extrafield=0;

	if (pfile_in_zip_read_info->read_buffer==NULL)
	{
		TRYFREE(pfile_in_zip_read_info);
		return UNZ_INTERNALERROR;
	}

	pfile_in_zip_read_info->stream_initialised=0;

	if ((s->cur_file_info.compression_method!=0) &&
		(s->cur_file_info.compression_method!=Z_DEFLATED))
		err=UNZ_BADZIPFILE;
	Store = s->cur_file_info.compression_method==0;

	pfile_in_zip_read_info->crc32_wait=s->cur_file_info.crc;
	pfile_in_zip_read_info->crc32=0;
	pfile_in_zip_read_info->compression_method =
		s->cur_file_info.compression_method;
	pfile_in_zip_read_info->file=s->file;
	pfile_in_zip_read_info->byte_before_the_zipfile=s->byte_before_the_zipfile;

	pfile_in_zip_read_info->stream.total_out = 0;

	if (!Store)
	{
		pfile_in_zip_read_info->stream.zalloc = (alloc_func)0;
		pfile_in_zip_read_info->stream.zfree = (free_func)0;
		pfile_in_zip_read_info->stream.opaque = (voidp)0; 

		err=inflateInit2(&pfile_in_zip_read_info->stream, -MAX_WBITS);
		if (err == Z_OK)
			pfile_in_zip_read_info->stream_initialised=1;
		/* 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
		*/
	}
	pfile_in_zip_read_info->rest_read_compressed = 
		s->cur_file_info.compressed_size ;
	pfile_in_zip_read_info->rest_read_uncompressed = 
		s->cur_file_info.u