Gzip Class

Properties   Methods   Events   Config Settings   Errors  

The Gzip class implements a gzip compressor and decompressor. It is compliant with RFC 1952 and compatible with the UNIX gzip and gunzip utilities.

Syntax

Gzip

Remarks

The gzip file format is typically used only to archive a single file. Accordingly, the operation of the class is simpler than that of the other classs.

To compress with the class, set ArchiveFile to the name of the gzip file to be created, and FileDecompressedName to the name of the file to be compressed. Finally, invoke Compress. To extract the file, first set ArchiveFile. FileDecompressedName may then be set; if not, it will automatically be set from the gzip file headers. Finally, invoke the Extract or Compress method.

.tar.gz files may be created or extracted in one step by using the Tar class. See the documentation for Tar for more details.

Example (Creating a Gzip File)

ZipControl.ArchiveFile = "c:\test.gz" ZipControl.FileDecompressedName = "c:\test.txt" ZipControl.Compress() Example (Extracting from a Gzip File)

ZipControl.ArchiveFile = "c:\test.gz" ZipControl.Scan() ZipControl.FileDecompressedName = "c:\test.txt" ZipControl.Extract()

Property List


The following is the full list of the properties of the class with short descriptions. Click on the links for further details.

ArchiveFileThe name of the zip, gzip, tar, or jar archive.
CompressionLevelThe compression level to use.
CompressionMethodThe compression method for the class to use.
ExtractToPathA base path to decompress to.
FileCompressedDateThe date and time of the compressed file, as stored within the gzip archive.
FileCompressedNameFilename, as stored inside of the archive.
FileDecompressedNameFile name to decompress to, or compress from.
FileDecompressedSizeGets the size of the file, as decompressed outside the archive.
FileInputDataThe data of the file to be compressed.
GzipData(Decompression only) The gzip file contents as a byte array.
HasMoreDataShows whether or not there is more data in the gzip archive.

Method List


The following is the full list of the methods of the class with short descriptions. Click on the links for further details.

AbortAborts the current operation.
AppendAdds specified file to an existing archive.
CompressCreates the compressed gzip archive.
ConfigSets or retrieves a configuration setting.
ExtractExtracts the compressed file from the gzip archive.
ExtractAllExtracts all files from the compressed archive.
ResetResets the class.
ScanScans the compressed archive.
SetArchiveInputStreamThe stream to read the zip, tar, jar, or gzip archive from.
SetArchiveOutputStreamThe stream to write the zip, tar, jar, or gzip archive to.
SetFileInputStreamThe input stream to read the decompressed data from.

Event List


The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.

BeginFileFired before a file is processed.
EndFileFired after a file is processed.
ErrorInformation about non-fatal errors.
OverwriteFired whenever a file exists and may be overwritten.
ProgressFired as progress is made.

Config Settings


The following is a list of config settings for the class with short descriptions. Click on the links for further details.

FileCommentHolds the comment associated with the archive.
PreserveModifiedTimeWhether or not to preserve the original modified time on extracted files.
WriteToProgressEventWhether or not to write data to the Progress Event.
BuildInfoInformation about the product's build.
CodePageThe system code page used for Unicode to Multibyte translations.
LicenseInfoInformation about the current license.
MaskSensitiveWhether sensitive data is masked in log messages.
ProcessIdleEventsWhether the class uses its internal event loop to process events when the main thread is idle.
SelectWaitMillisThe length of time in milliseconds the class will wait when DoEvents is called if there are no events to process.
UseInternalSecurityAPITells the class whether or not to use the system security libraries or an internal implementation.

ArchiveFile Property (Gzip Class)

The name of the zip, gzip, tar, or jar archive.

Syntax

ANSI (Cross Platform)
char* GetArchiveFile();
int SetArchiveFile(const char* lpszArchiveFile); Unicode (Windows) LPWSTR GetArchiveFile();
INT SetArchiveFile(LPCWSTR lpszArchiveFile);
char* ipworkszip_gzip_getarchivefile(void* lpObj);
int ipworkszip_gzip_setarchivefile(void* lpObj, const char* lpszArchiveFile);
QString GetArchiveFile();
int SetArchiveFile(QString qsArchiveFile);

Default Value

""

Remarks

This property specifies the name of the archive to be read or written. This property is required when extracting files.

When Scan, Extract, or ExtractAll is invoked, the file specified by ArchiveFile will be opened for read. If the file does not exist, a trappable error will be generated.

When Compress is called, the file named by ArchiveFile will be written; if a file of this name already exists the Overwrite event will be fired. If ArchiveFile is set to the empty string (""), the archive will not be written to disk, and will be provided only through the Progress event.

The filename may be specified with or without a path. Paths may be relative or absolute, and should be specified in the format native to the host operating system. The filename should be specified with the appropriate extension (such as "zip"); an extension will not automatically be appended by the class.

If the file cannot be read, or written, as appropriate, a trappable error will be generated.

Example (Creating an Archive)

ZipControl.ArchiveFile = "c:\test.zip" ZipControl.RecurseSubdirectories = true ZipControl.IncludeFiles("c:\foo\*") ZipControl.Compress()

Note: an archive already open for read may be closed by setting ArchiveFile to the empty string ("").

Data Type

String

CompressionLevel Property (Gzip Class)

The compression level to use.

Syntax

ANSI (Cross Platform)
int GetCompressionLevel();
int SetCompressionLevel(int iCompressionLevel); Unicode (Windows) INT GetCompressionLevel();
INT SetCompressionLevel(INT iCompressionLevel);
int ipworkszip_gzip_getcompressionlevel(void* lpObj);
int ipworkszip_gzip_setcompressionlevel(void* lpObj, int iCompressionLevel);
int GetCompressionLevel();
int SetCompressionLevel(int iCompressionLevel);

Default Value

4

Remarks

This property specifies the level of compression to be used, between 1 and 6. Higher values will cause the class to compress better; lower values will cause the class to compress faster.

Storing without compression is not supported for Gzip.

Data Type

Integer

CompressionMethod Property (Gzip Class)

The compression method for the class to use.

Syntax

ANSI (Cross Platform)
int GetCompressionMethod();
int SetCompressionMethod(int iCompressionMethod); Unicode (Windows) INT GetCompressionMethod();
INT SetCompressionMethod(INT iCompressionMethod);

Possible Values

CMG_DEFLATE(0), 
CMG_LZCCOMPRESS(1)
int ipworkszip_gzip_getcompressionmethod(void* lpObj);
int ipworkszip_gzip_setcompressionmethod(void* lpObj, int iCompressionMethod);
int GetCompressionMethod();
int SetCompressionMethod(int iCompressionMethod);

Default Value

0

Remarks

By default, the component uses the Deflate compression method described in rfc 1952. When set to LZC compress method, the component will use a variation of the method described by the LZW (Lempel-Ziv-Welch) algorithm that is compatible with Unix's compress utility.

Data Type

Integer

ExtractToPath Property (Gzip Class)

A base path to decompress to.

Syntax

ANSI (Cross Platform)
char* GetExtractToPath();
int SetExtractToPath(const char* lpszExtractToPath); Unicode (Windows) LPWSTR GetExtractToPath();
INT SetExtractToPath(LPCWSTR lpszExtractToPath);
char* ipworkszip_gzip_getextracttopath(void* lpObj);
int ipworkszip_gzip_setextracttopath(void* lpObj, const char* lpszExtractToPath);
QString GetExtractToPath();
int SetExtractToPath(QString qsExtractToPath);

Default Value

""

Remarks

Setting the ExtractToPath property affects the operation of the Extract and ExtractAll methods. Setting this property to a nonempty string will cause all decompressed files to be written to the specified path. If pathnames are given in the values of FileDecompressedName they will be regarded as relative to ExtractToPath.

If the specified directory does not exist, it will be created when extraction is done.

ExtractToPath should always be specified in the format native to the host operating system, and with a trailing slash or backslash. If the path is specified otherwise, it will be immediately converted and stored in the converted format. For example, "/temp" would be immediately converted to "\temp\" on a Windows system.

Example (Extracting from an Archive)

ZipControl.ArchiveFile = "c:\temp.zip" ZipControl.ExtractToPath = "c:\extracted\" ZipControl.ExtractAll()

Data Type

String

FileCompressedDate Property (Gzip Class)

The date and time of the compressed file, as stored within the gzip archive.

Syntax

ANSI (Cross Platform)
int64 GetFileCompressedDate();

Unicode (Windows)
LONG64 GetFileCompressedDate();
int64 ipworkszip_gzip_getfilecompresseddate(void* lpObj);
qint64 GetFileCompressedDate();

Default Value

0

Remarks

FileCompressedDate contains the last modified date of the file, as stored within the archive (it does not generally correspond to when the file was compressed).

FileCompressedDate is returned in a platform-specific format. The Java and other editions will return the number of milliseconds since January 1, 1970, 00:00:00. This value may be passed directly to the java.util.Date constructor to create a java.util.Date object representing this date.

The .NET Edition will return the number of ticks, or 100-nanosecond intervals, since January 1, 0001, 00:00:00. This value may be passed directly to the System.DateTime constructor to create a System.DateTime object representing this date.

Reading the value of this property will return a meaningful value only after a call to Scan or Extract. If a meaningful value is not available this property will return a value of 0.

This property is read-only and not available at design time.

Data Type

Long64

FileCompressedName Property (Gzip Class)

Filename, as stored inside of the archive.

Syntax

ANSI (Cross Platform)
char* GetFileCompressedName();
int SetFileCompressedName(const char* lpszFileCompressedName); Unicode (Windows) LPWSTR GetFileCompressedName();
INT SetFileCompressedName(LPCWSTR lpszFileCompressedName);
char* ipworkszip_gzip_getfilecompressedname(void* lpObj);
int ipworkszip_gzip_setfilecompressedname(void* lpObj, const char* lpszFileCompressedName);
QString GetFileCompressedName();
int SetFileCompressedName(QString qsFileCompressedName);

Default Value

""

Remarks

FileCompressedName contains the name of the compressed file, as stored within the gzip header.

This field should generally be set with a relative path or with no path at all. The exact interpretation of the path is left to the decompression software; generally, pathnames will be interpreted as relative to a base directory, and these subdirectories will be created as needed. Absolute pathnames (paths beginning with a / character) will not be interpreted correctly by the class, and may or may not be interpreted correctly by other decompression software.

Paths should be specified in standard (UNIX) format. They may also be specified in the format native to the host operating system, in which case they will be immediately converted.

It is not usually necessary to manually set the value of this property; it will be assigned by Compress if it is not specified, and it will always be written by a call to Scan or Extract.

Data Type

String

FileDecompressedName Property (Gzip Class)

File name to decompress to, or compress from.

Syntax

ANSI (Cross Platform)
char* GetFileDecompressedName();
int SetFileDecompressedName(const char* lpszFileDecompressedName); Unicode (Windows) LPWSTR GetFileDecompressedName();
INT SetFileDecompressedName(LPCWSTR lpszFileDecompressedName);
char* ipworkszip_gzip_getfiledecompressedname(void* lpObj);
int ipworkszip_gzip_setfiledecompressedname(void* lpObj, const char* lpszFileDecompressedName);
QString GetFileDecompressedName();
int SetFileDecompressedName(QString qsFileDecompressedName);

Default Value

""

Remarks

FileDecompressedName contains the name of the file in the archive, as stored on the file system, outside the archive.

When compressing a file, this property should be specified with a path, if necessary, to allow the file to be found by the class. If the file cannot be found when Compress is called, a trappable error will be generated, and the archive will not be correctly written.

When decompressing files, this property may be set after calling Scan and prior to calling Extract. If this property is set to the empty string when Extract is called, Extract will automatically set this property to an appropriate value.

Note: If Scan is not called before Extract, the component will internally call the method and any value in FileDecompressedName will be overwritten.

Paths on the local file system should be specified in the format native to the host operating system. They may also be specified in standard (UNIX) format, in which case they will be immediately converted.

Data Type

String

FileDecompressedSize Property (Gzip Class)

Gets the size of the file, as decompressed outside the archive.

Syntax

ANSI (Cross Platform)
int64 GetFileDecompressedSize();

Unicode (Windows)
LONG64 GetFileDecompressedSize();
int64 ipworkszip_gzip_getfiledecompressedsize(void* lpObj);
qint64 GetFileDecompressedSize();

Default Value

-1

Remarks

This property holds the decompressed size of the file. If an archive is open for read (i.e. has been scanned or decompressed), this information will be read from the archive headers. If an archive is not open for read, the component will retrieve the information for the corresponding value of DecompressedName from the local file system.

A value of -1 will be returned in case of an I/O error.

This property is read-only and not available at design time.

Data Type

Long64

FileInputData Property (Gzip Class)

The data of the file to be compressed.

Syntax

ANSI (Cross Platform)
int GetFileInputData(char* &lpFileInputData, int &lenFileInputData);
int SetFileInputData(const char* lpFileInputData, int lenFileInputData); Unicode (Windows) INT GetFileInputData(LPSTR &lpFileInputData, INT &lenFileInputData);
INT SetFileInputData(LPCSTR lpFileInputData, INT lenFileInputData);
int ipworkszip_gzip_getfileinputdata(void* lpObj, char** lpFileInputData, int* lenFileInputData);
int ipworkszip_gzip_setfileinputdata(void* lpObj, const char* lpFileInputData, int lenFileInputData);
QByteArray GetFileInputData();
int SetFileInputData(QByteArray qbaFileInputData);

Default Value

""

Remarks

When this property is set, the class will read in the data from this property instead of reading from the file contained in the FileDecompressedName property.

This property is not available at design time.

Data Type

Binary String

GzipData Property (Gzip Class)

(Decompression only) The gzip file contents as a byte array.

Syntax

ANSI (Cross Platform)
int SetGzipData(const char* lpGzipData, int lenGzipData);

Unicode (Windows)
INT SetGzipData(LPCSTR lpGzipData, INT lenGzipData);
int ipworkszip_gzip_setgzipdata(void* lpObj, const char* lpGzipData, int lenGzipData);
int SetGzipData(QByteArray qbaGzipData);

Default Value

""

Remarks

Normally you should set ArchiveFile before invoking Scan or Extract. If you prefer to read the gzip file from memory you may set GzipData instead. GzipData should be set to the entire contents of the gzip file; this will allow you to read from the archive without writing any temporary files to disk.

If you would like to extract data from the archive without ever writing to disk you should also set WriteToProgressEvent to true, and after invoking Scan, you should set the value of FileDecompressedName to an empty string. Then, when you invoke Extract (or ExtractAll) the data will be provided in the Progress event.

This property is write-only. Note that modifying a gzip file stored in GzipData is not supported, so Append will throw exceptions.

This property is write-only and not available at design time.

Data Type

Binary String

HasMoreData Property (Gzip Class)

Shows whether or not there is more data in the gzip archive.

Syntax

ANSI (Cross Platform)
int GetHasMoreData();

Unicode (Windows)
BOOL GetHasMoreData();
int ipworkszip_gzip_gethasmoredata(void* lpObj);
bool GetHasMoreData();

Default Value

FALSE

Remarks

The Gzip format described in RFC 1952 allows multiple gzipped data members to be concatenated into a single file. However, due to the nature of the algorithm it is impossible to determine the number of data members until after the entire archive has been decompressed. The HasMoreData property can be used to cycle through the archive and extract each file.

Simply set the ArchiveFile and ExtractToPath properties, then call Extract as long as the class has available data.

Note: the class will not update FileDecompressedName unless you call Scan or manually set FileDecompressedName on each loop before calling Extract.

Example (Extracting Multiple Files)

ZipControl.ArchiveFile = "c:\temp.zip" ZipControl.ExtractToPath = "c:\extracted\" Do ZipControl.Scan() //here you may inspect the file name in FileDecompressedName prior to extraction ZipControl.Extract() While ZipControl.HasMoreData

This property is read-only.

Data Type

Boolean

Abort Method (Gzip Class)

Aborts the current operation.

Syntax

ANSI (Cross Platform)
int Abort();

Unicode (Windows)
INT Abort();
int ipworkszip_gzip_abort(void* lpObj);
int Abort();

Remarks

Abort may be used to immediately interrupt compression or decompression. Any files partially written by the class will be deleted.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

Append Method (Gzip Class)

Adds specified file to an existing archive.

Syntax

ANSI (Cross Platform)
int Append();

Unicode (Windows)
INT Append();
int ipworkszip_gzip_append(void* lpObj);
int Append();

Remarks

The file contained in the FileDecompressedName property will be appended to the archive specified by ArchiveFile.

This method may only be used to add files to an existing archive. To add files to a new archive, Compress method should be used.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

Compress Method (Gzip Class)

Creates the compressed gzip archive.

Syntax

ANSI (Cross Platform)
int Compress();

Unicode (Windows)
INT Compress();
int ipworkszip_gzip_compress(void* lpObj);
int Compress();

Remarks

Invoking Compress creates the archive specified by ArchiveFile. When the method is called, the file specified by FileDecompressedName will be opened, and the file specified by ArchiveFile will contain the compressed output.

The filename to be stored within the archive is given by FileCompressedName. If this property is set to the empty string, it will be set to an appropriate value automatically; the class always writes a filename in the gzip headers.

As the data is compressed the Progress event will be fired at regular intervals. This event may be used to stream out the gzip file, or to display a progress bar to the user.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

Config Method (Gzip Class)

Sets or retrieves a configuration setting.

Syntax

ANSI (Cross Platform)
char* Config(const char* lpszConfigurationString);

Unicode (Windows)
LPWSTR Config(LPCWSTR lpszConfigurationString);
char* ipworkszip_gzip_config(void* lpObj, const char* lpszConfigurationString);
QString Config(const QString& qsConfigurationString);

Remarks

Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Error Handling (C++)

This method returns a String value; after it returns, call the GetLastErrorCode() method to obtain its result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message.

Extract Method (Gzip Class)

Extracts the compressed file from the gzip archive.

Syntax

ANSI (Cross Platform)
int Extract();

Unicode (Windows)
INT Extract();
int ipworkszip_gzip_extract(void* lpObj);
int Extract();

Remarks

Invoking Extract decompresses the archive specified by ArchiveFile. The compressed file will be extracted, and written to disk. Also, FileCompressedName will be set to the filename found in the archive.

If FileDecompressedName is set to a nonempty string the file will be written there. Otherwise the class will automatically set FileDecompressedName to an appropriate value:

If a filename (i.e., FileCompressedName) is stored in the gzip headers, this filename will be used.

Otherwise, if ArchiveFile ends in ".gz", this filename, less the ".gz" extension will be used. If there are multiple files in the archive, the current 0-based file index will be appended to all files after the first file to differentiate between multiple files. For instance "test.gz" would become "test" for the first file and "test.gz" would become "test.1" for the second file in the archive.

If neither of these two conditions holds, ".unzipped" will be appended to ArchiveFile.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

ExtractAll Method (Gzip Class)

Extracts all files from the compressed archive.

Syntax

ANSI (Cross Platform)
int ExtractAll();

Unicode (Windows)
INT ExtractAll();
int ipworkszip_gzip_extractall(void* lpObj);
int ExtractAll();

Remarks

ExtractAll extracts all files from the archive. The file(s) will be extracted to the directory specified by ExtractToPath, and given the names found in the archive or specified by FileDecompressedName.

If Scan has not been invoked when ExtractAll is called, Scan will automatically be invoked, and the FileCompressedName and FileDecompressedName properties will be set to the values found in the archive. To manually set the decompressed filenames, Scan should be invoked before setting FileDecompressedName.

The BeginFile and EndFile events will be fired before and after each file is extracted, and the Progress event will be fired as the data is extracted. If WriteToProgressEvent is set to true, the decompressed data will be streamed out through the Progress event.

Example (Extracting from an Archive)

ZipControl.ArchiveFile = "c:\temp.zip" ZipControl.ExtractToPath = "c:\extracted\" ZipControl.ExtractAll()

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

Reset Method (Gzip Class)

Resets the class.

Syntax

ANSI (Cross Platform)
int Reset();

Unicode (Windows)
INT Reset();
int ipworkszip_gzip_reset(void* lpObj);
int Reset();

Remarks

Reset resets the state of the class. All properties will be set to their default values, and any files open will be closed.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

Scan Method (Gzip Class)

Scans the compressed archive.

Syntax

ANSI (Cross Platform)
int Scan();

Unicode (Windows)
INT Scan();
int ipworkszip_gzip_scan(void* lpObj);
int Scan();

Remarks

This method will scan the gzip archive specified by ArchiveFile. The archive will be read, the header will be checked, and the stored filename will be written to FileCompressedName.

Unlike in the Zip, Tar, and Jar classs, it is never necessary to invoke this method, and it will not be automatically invoked by Extract. Suggested uses for this method would be to check that the file is a gzip file, or to determine an appropriate value for FileDecompressedName.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

SetArchiveInputStream Method (Gzip Class)

The stream to read the zip, tar, jar, or gzip archive from.

Syntax

ANSI (Cross Platform)
int SetArchiveInputStream(IPWorksZipStream* sArchiveStream);

Unicode (Windows)
INT SetArchiveInputStream(IPWorksZipStream* sArchiveStream);
int ipworkszip_gzip_setarchiveinputstream(void* lpObj, IPWorksZipStream* sArchiveStream);
int SetArchiveInputStream(IPWorksZipStream* sArchiveStream);

Remarks

This method should be set when the archive is to be read from a stream when Extract is called.

By default, and when this is set to null, the class will read from the file specified by ArchiveFile. However, when this is a valid stream, the data will be read from the stream.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

SetArchiveOutputStream Method (Gzip Class)

The stream to write the zip, tar, jar, or gzip archive to.

Syntax

ANSI (Cross Platform)
int SetArchiveOutputStream(IPWorksZipStream* sArchiveStream);

Unicode (Windows)
INT SetArchiveOutputStream(IPWorksZipStream* sArchiveStream);
int ipworkszip_gzip_setarchiveoutputstream(void* lpObj, IPWorksZipStream* sArchiveStream);
int SetArchiveOutputStream(IPWorksZipStream* sArchiveStream);

Remarks

This method should be set when the archive is to be written to a stream when Compress is called.

By default, and when this is set to null, the class will write to the file specified by ArchiveFile. However, when this is a valid stream, the data will be written to the stream.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

SetFileInputStream Method (Gzip Class)

The input stream to read the decompressed data from.

Syntax

ANSI (Cross Platform)
int SetFileInputStream(IPWorksZipStream* sArchiveStream);

Unicode (Windows)
INT SetFileInputStream(IPWorksZipStream* sArchiveStream);
int ipworkszip_gzip_setfileinputstream(void* lpObj, IPWorksZipStream* sArchiveStream);
int SetFileInputStream(IPWorksZipStream* sArchiveStream);

Remarks

When this method is set to a valid stream, the class will read in the data from the stream as the current file instead of reading from the file contained in the FileDecompressedName property.

Error Handling (C++)

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)

BeginFile Event (Gzip Class)

Fired before a file is processed.

Syntax

ANSI (Cross Platform)
virtual int FireBeginFile(GzipBeginFileEventParams *e);
typedef struct {
int Index;
int Skip; int reserved; } GzipBeginFileEventParams;
Unicode (Windows) virtual INT FireBeginFile(GzipBeginFileEventParams *e);
typedef struct {
INT Index;
BOOL Skip; INT reserved; } GzipBeginFileEventParams;
#define EID_GZIP_BEGINFILE 1

virtual INT IPWORKSZIP_CALL FireBeginFile(INT &iIndex, BOOL &bSkip);
class GzipBeginFileEventParams {
public:
  int Index();

  bool Skip();
  void SetSkip(bool bSkip);

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};
// To handle, connect one or more slots to this signal. void BeginFile(GzipBeginFileEventParams *e);
// Or, subclass Gzip and override this emitter function. virtual int FireBeginFile(GzipBeginFileEventParams *e) {...}

Remarks

BeginFile is fired before compression or decompression begins. Index will contain 0.

You may use the Skip parameter to tell the class to skip the file when appending or decompressing.

EndFile Event (Gzip Class)

Fired after a file is processed.

Syntax

ANSI (Cross Platform)
virtual int FireEndFile(GzipEndFileEventParams *e);
typedef struct {
int Index; int reserved; } GzipEndFileEventParams;
Unicode (Windows) virtual INT FireEndFile(GzipEndFileEventParams *e);
typedef struct {
INT Index; INT reserved; } GzipEndFileEventParams;
#define EID_GZIP_ENDFILE 2

virtual INT IPWORKSZIP_CALL FireEndFile(INT &iIndex);
class GzipEndFileEventParams {
public:
  int Index();

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};
// To handle, connect one or more slots to this signal. void EndFile(GzipEndFileEventParams *e);
// Or, subclass Gzip and override this emitter function. virtual int FireEndFile(GzipEndFileEventParams *e) {...}

Remarks

EndFile is fired when compression or decompression finishes. Index will contain 0.

Error Event (Gzip Class)

Information about non-fatal errors.

Syntax

ANSI (Cross Platform)
virtual int FireError(GzipErrorEventParams *e);
typedef struct {
const char *Description;
int ErrorCode;
int Index;
const char *Filename;
int Ignore; int reserved; } GzipErrorEventParams;
Unicode (Windows) virtual INT FireError(GzipErrorEventParams *e);
typedef struct {
LPCWSTR Description;
INT ErrorCode;
INT Index;
LPCWSTR Filename;
BOOL Ignore; INT reserved; } GzipErrorEventParams;
#define EID_GZIP_ERROR 3

virtual INT IPWORKSZIP_CALL FireError(LPSTR &lpszDescription, INT &iErrorCode, INT &iIndex, LPSTR &lpszFilename, BOOL &bIgnore);
class GzipErrorEventParams {
public:
  const QString &Description();

  int ErrorCode();

  int Index();

  const QString &Filename();

  bool Ignore();
  void SetIgnore(bool bIgnore);

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};
// To handle, connect one or more slots to this signal. void Error(GzipErrorEventParams *e);
// Or, subclass Gzip and override this emitter function. virtual int FireError(GzipErrorEventParams *e) {...}

Remarks

The Error event is fired when non-fatal errors occur during compression or decompression. Note that if this event is fired during decompression this may indicate that the archive is corrupt.

By default these errors will cause the component to fail with an exception. The exception may be overridden by setting Ignore to true. This will cause the error to be ignored, the file will be skipped if necessary, and the class will continue operation.

ErrorCode will correspond to one of the following errors:

1Bad or missing CRC-32 checksum.
2Failed to set creation date of a file.
111Can't open file for read (skipping).

Description contains a textual description of the error. Index and Filename contain the array index (where appropriate) and filename of the file being processed at the time of the error.

Overwrite Event (Gzip Class)

Fired whenever a file exists and may be overwritten.

Syntax

ANSI (Cross Platform)
virtual int FireOverwrite(GzipOverwriteEventParams *e);
typedef struct {
char *Filename;
int Overwrite; int reserved; } GzipOverwriteEventParams;
Unicode (Windows) virtual INT FireOverwrite(GzipOverwriteEventParams *e);
typedef struct {
LPWSTR Filename;
BOOL Overwrite; INT reserved; } GzipOverwriteEventParams;
#define EID_GZIP_OVERWRITE 4

virtual INT IPWORKSZIP_CALL FireOverwrite(LPSTR &lpszFilename, BOOL &bOverwrite);
class GzipOverwriteEventParams {
public:
  const QString &Filename();
  void SetFilename(const QString &qsFilename);

  bool Overwrite();
  void SetOverwrite(bool bOverwrite);

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};
// To handle, connect one or more slots to this signal. void Overwrite(GzipOverwriteEventParams *e);
// Or, subclass Gzip and override this emitter function. virtual int FireOverwrite(GzipOverwriteEventParams *e) {...}

Remarks

Overwrite is fired when a file is about to be overwritten, and would overwrite an existing file. The event is fired during decompression.

Filename contains the full name of the file, specified with its pathname.

Overwrite specifies whether or not the file will be overwritten. For Zip, Jar, and Tar, this is equal by default to the value of the OverwriteFiles property. For Gzip, this value defaults to true.

Either of the parameters may be changed when the event is fired. Changing the value of Overwrite will override the default behavior of the class, and cause the file to be overwritten or not overwritten, depending on the value set. If Filename is changed, the value of Overwrite will be ignored, and the file will be written with the specified name. If a file of the new name also exists this file will be silently overwritten.

Progress Event (Gzip Class)

Fired as progress is made.

Syntax

ANSI (Cross Platform)
virtual int FireProgress(GzipProgressEventParams *e);
typedef struct {
const char *Data; int lenData;
const char *Filename;
int64 BytesProcessed;
int PercentProcessed; int reserved; } GzipProgressEventParams;
Unicode (Windows) virtual INT FireProgress(GzipProgressEventParams *e);
typedef struct {
LPCSTR Data; INT lenData;
LPCWSTR Filename;
LONG64 BytesProcessed;
INT PercentProcessed; INT reserved; } GzipProgressEventParams;
#define EID_GZIP_PROGRESS 5

virtual INT IPWORKSZIP_CALL FireProgress(LPSTR &lpData, INT &lenData, LPSTR &lpszFilename, LONG64 &lBytesProcessed, INT &iPercentProcessed);
class GzipProgressEventParams {
public:
  const QByteArray &Data();

  const QString &Filename();

  qint64 BytesProcessed();

  int PercentProcessed();

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};
// To handle, connect one or more slots to this signal. void Progress(GzipProgressEventParams *e);
// Or, subclass Gzip and override this emitter function. virtual int FireProgress(GzipProgressEventParams *e) {...}

Remarks

The Progress event is automatically fired as compression or decompression is performed. When WriteToProgressEvent is true, the output data is provided through the Data parameter, allowing for it to be streamed out.

Filename contains the name of the file being written. If no file is being written, Filename will contain an empty string, and the output data will be provided exclusively through this event.

BytesProcessed contains the total number of uncompressed bytes processed. PercentProcessed contains the percent of uncompressed bytes processed, corresponding roughly to the running time of the operation.

For Gzip extraction only, BytesProcessed and PercentProcessed will reflect the number of compressed bytes extracted, as it is generally impossible to predetermine the total uncompressed size.

If WriteToProgressEvent is false, Data will contain null.

IPWorksZipStream Type

Syntax

IPWorksZipStream (declared in ipworkszip.h)

Remarks

The Gzip class includes one or more API members that take a stream object as a parameter. To use such API members, create a concrete class that implements the IPWorksZipStream interface and pass the Gzip class an instance of that concrete class.

When implementing the IPWorksZipStream interface's properties and methods, they must behave as described below. If the concrete class's implementation does not behave as expected, undefined behavior may occur.

Properties

CanRead Whether the stream supports reading.

bool CanRead() { return true; }
CanSeek Whether the stream supports seeking.

bool CanSeek() { return true; }
CanWrite Whether the stream supports writing.

bool CanWrite() { return true; }
Length Gets the length of the stream, in bytes.

int64 GetLength() = 0;

Methods

Close Closes the stream, releasing all resources currently allocated for it.

void Close() {}

This method is called automatically when an IPWorksZipStream object is deleted.

Flush Forces all data held by the stream's buffers to be written out to storage.

int Flush() { return 0; }

Must return 0 if flushing is successful; or -1 if an error occurs or the stream is closed. If the stream does not support writing, this method must do nothing and return 0.

Read Reads a sequence of bytes from the stream and advances the current position within the stream by the number of bytes read.

int Read(void* buffer, int count) = 0;

Buffer specifies the buffer to populate with data from the stream. Count specifies the number of bytes that should be read from the stream.

Must return the total number of bytes read into Buffer; this may be less than Count if that many bytes are not currently available, or 0 if the end of the stream has been reached. Must return -1 if an error occurs, if reading is not supported, or if the stream is closed.

Seek Sets the current position within the stream based on a particular point of origin.

int64 Seek(int64 offset, int seekOrigin) = 0;

Offset specifies the offset in the stream to seek to, relative to SeekOrigin. Valid values for SeekOrigin are:

  • 0: Seek from beginning.
  • 1: Seek from current position.
  • 2: Seek from end.

Must return the new position within the stream; or -1 if an error occurs, if seeking is not supported, or if the stream is closed (however, see note below). If -1 is returned, the current position within the stream must remain unchanged.

Note: If the stream is not closed, it must always be possible to call this method with an Offset of 0 and a SeekOrigin of 1 to obtain the current position within the stream, even if seeking is not otherwise supported.

Write Writes a sequence of bytes to the stream and advances the current position within the stream by the number of bytes written.

int Write(const void* buffer, int count) = 0;

Buffer specifies the buffer with data to write to the stream. Count specifies the number of bytes that should be written to the stream.

Must return the total number of bytes written to the stream; this may be less than Count if that many bytes could not be written. Must return -1 if an error occurs, if writing is not supported, or if the stream is closed.

Config Settings (Gzip Class)

The class accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

Gzip Config Settings

FileComment:   Holds the comment associated with the archive.

When compressing this may be set to include a comment in the archive. This will also hold the comment associated with an archive after calling Scan.

PreserveModifiedTime:   Whether or not to preserve the original modified time on extracted files.

Specifies whether or not the modified time of the extracted files use the current time or the original time of the file in the archive.

When set to True (default) the extracted files will have the same modified time as the original file.

When set to False the modified time on the extracted files will be set to the current time.

WriteToProgressEvent:   Whether or not to write data to the Progress Event.

If WriteToProgressEvent is set to true, then all data produced through invocations of Extract, ExtractAll, and Compress will be written to the Progress event as well as to disk. Applications may stream out the compressed or decompressed data by trapping this event and copying the data.

If WriteToProgressEvent is set to false, the data will not be streamed out, and the Data parameter of the Progress event will contain null.

By default, this config is set to false.

Base Config Settings

BuildInfo:   Information about the product's build.

When queried, this setting will return a string containing information about the product's build.

CodePage:   The system code page used for Unicode to Multibyte translations.

The default code page is Unicode UTF-8 (65001).

The following is a list of valid code page identifiers:

IdentifierName
037IBM EBCDIC - U.S./Canada
437OEM - United States
500IBM EBCDIC - International
708Arabic - ASMO 708
709Arabic - ASMO 449+, BCON V4
710Arabic - Transparent Arabic
720Arabic - Transparent ASMO
737OEM - Greek (formerly 437G)
775OEM - Baltic
850OEM - Multilingual Latin I
852OEM - Latin II
855OEM - Cyrillic (primarily Russian)
857OEM - Turkish
858OEM - Multilingual Latin I + Euro symbol
860OEM - Portuguese
861OEM - Icelandic
862OEM - Hebrew
863OEM - Canadian-French
864OEM - Arabic
865OEM - Nordic
866OEM - Russian
869OEM - Modern Greek
870IBM EBCDIC - Multilingual/ROECE (Latin-2)
874ANSI/OEM - Thai (same as 28605, ISO 8859-15)
875IBM EBCDIC - Modern Greek
932ANSI/OEM - Japanese, Shift-JIS
936ANSI/OEM - Simplified Chinese (PRC, Singapore)
949ANSI/OEM - Korean (Unified Hangul Code)
950ANSI/OEM - Traditional Chinese (Taiwan; Hong Kong SAR, PRC)
1026IBM EBCDIC - Turkish (Latin-5)
1047IBM EBCDIC - Latin 1/Open System
1140IBM EBCDIC - U.S./Canada (037 + Euro symbol)
1141IBM EBCDIC - Germany (20273 + Euro symbol)
1142IBM EBCDIC - Denmark/Norway (20277 + Euro symbol)
1143IBM EBCDIC - Finland/Sweden (20278 + Euro symbol)
1144IBM EBCDIC - Italy (20280 + Euro symbol)
1145IBM EBCDIC - Latin America/Spain (20284 + Euro symbol)
1146IBM EBCDIC - United Kingdom (20285 + Euro symbol)
1147IBM EBCDIC - France (20297 + Euro symbol)
1148IBM EBCDIC - International (500 + Euro symbol)
1149IBM EBCDIC - Icelandic (20871 + Euro symbol)
1200Unicode UCS-2 Little-Endian (BMP of ISO 10646)
1201Unicode UCS-2 Big-Endian
1250ANSI - Central European
1251ANSI - Cyrillic
1252ANSI - Latin I
1253ANSI - Greek
1254ANSI - Turkish
1255ANSI - Hebrew
1256ANSI - Arabic
1257ANSI - Baltic
1258ANSI/OEM - Vietnamese
1361Korean (Johab)
10000MAC - Roman
10001MAC - Japanese
10002MAC - Traditional Chinese (Big5)
10003MAC - Korean
10004MAC - Arabic
10005MAC - Hebrew
10006MAC - Greek I
10007MAC - Cyrillic
10008MAC - Simplified Chinese (GB 2312)
10010MAC - Romania
10017MAC - Ukraine
10021MAC - Thai
10029MAC - Latin II
10079MAC - Icelandic
10081MAC - Turkish
10082MAC - Croatia
12000Unicode UCS-4 Little-Endian
12001Unicode UCS-4 Big-Endian
20000CNS - Taiwan
20001TCA - Taiwan
20002Eten - Taiwan
20003IBM5550 - Taiwan
20004TeleText - Taiwan
20005Wang - Taiwan
20105IA5 IRV International Alphabet No. 5 (7-bit)
20106IA5 German (7-bit)
20107IA5 Swedish (7-bit)
20108IA5 Norwegian (7-bit)
20127US-ASCII (7-bit)
20261T.61
20269ISO 6937 Non-Spacing Accent
20273IBM EBCDIC - Germany
20277IBM EBCDIC - Denmark/Norway
20278IBM EBCDIC - Finland/Sweden
20280IBM EBCDIC - Italy
20284IBM EBCDIC - Latin America/Spain
20285IBM EBCDIC - United Kingdom
20290IBM EBCDIC - Japanese Katakana Extended
20297IBM EBCDIC - France
20420IBM EBCDIC - Arabic
20423IBM EBCDIC - Greek
20424IBM EBCDIC - Hebrew
20833IBM EBCDIC - Korean Extended
20838IBM EBCDIC - Thai
20866Russian - KOI8-R
20871IBM EBCDIC - Icelandic
20880IBM EBCDIC - Cyrillic (Russian)
20905IBM EBCDIC - Turkish
20924IBM EBCDIC - Latin-1/Open System (1047 + Euro symbol)
20932JIS X 0208-1990 & 0121-1990
20936Simplified Chinese (GB2312)
21025IBM EBCDIC - Cyrillic (Serbian, Bulgarian)
21027Extended Alpha Lowercase
21866Ukrainian (KOI8-U)
28591ISO 8859-1 Latin I
28592ISO 8859-2 Central Europe
28593ISO 8859-3 Latin 3
28594ISO 8859-4 Baltic
28595ISO 8859-5 Cyrillic
28596ISO 8859-6 Arabic
28597ISO 8859-7 Greek
28598ISO 8859-8 Hebrew
28599ISO 8859-9 Latin 5
28605ISO 8859-15 Latin 9
29001Europa 3
38598ISO 8859-8 Hebrew
50220ISO 2022 Japanese with no halfwidth Katakana
50221ISO 2022 Japanese with halfwidth Katakana
50222ISO 2022 Japanese JIS X 0201-1989
50225ISO 2022 Korean
50227ISO 2022 Simplified Chinese
50229ISO 2022 Traditional Chinese
50930Japanese (Katakana) Extended
50931US/Canada and Japanese
50933Korean Extended and Korean
50935Simplified Chinese Extended and Simplified Chinese
50936Simplified Chinese
50937US/Canada and Traditional Chinese
50939Japanese (Latin) Extended and Japanese
51932EUC - Japanese
51936EUC - Simplified Chinese
51949EUC - Korean
51950EUC - Traditional Chinese
52936HZ-GB2312 Simplified Chinese
54936Windows XP: GB18030 Simplified Chinese (4 Byte)
57002ISCII Devanagari
57003ISCII Bengali
57004ISCII Tamil
57005ISCII Telugu
57006ISCII Assamese
57007ISCII Oriya
57008ISCII Kannada
57009ISCII Malayalam
57010ISCII Gujarati
57011ISCII Punjabi
65000Unicode UTF-7
65001Unicode UTF-8
The following is a list of valid code page identifiers for Mac OS only:
IdentifierName
1ASCII
2NEXTSTEP
3JapaneseEUC
4UTF8
5ISOLatin1
6Symbol
7NonLossyASCII
8ShiftJIS
9ISOLatin2
10Unicode
11WindowsCP1251
12WindowsCP1252
13WindowsCP1253
14WindowsCP1254
15WindowsCP1250
21ISO2022JP
30MacOSRoman
10UTF16String
0x90000100UTF16BigEndian
0x94000100UTF16LittleEndian
0x8c000100UTF32String
0x98000100UTF32BigEndian
0x9c000100UTF32LittleEndian
65536Proprietary

LicenseInfo:   Information about the current license.

When queried, this setting will return a string containing information about the license this instance of a class is using. It will return the following information:

  • Product: The product the license is for.
  • Product Key: The key the license was generated from.
  • License Source: Where the license was found (e.g., RuntimeLicense, License File).
  • License Type: The type of license installed (e.g., Royalty Free, Single Server).
  • Last Valid Build: The last valid build number for which the license will work.
MaskSensitive:   Whether sensitive data is masked in log messages.

In certain circumstances it may be beneficial to mask sensitive data, like passwords, in log messages. Set this to true to mask sensitive data. The default is true.

This setting only works on these classes: AS3Receiver, AS3Sender, Atom, Client(3DS), FTP, FTPServer, IMAP, OFTPClient, SSHClient, SCP, Server(3DS), Sexec, SFTP, SFTPServer, SSHServer, TCPClient, TCPServer.

ProcessIdleEvents:   Whether the class uses its internal event loop to process events when the main thread is idle.

If set to False, the class will not fire internal idle events. Set this to False to use the class in a background thread on Mac OS. By default, this setting is True.

SelectWaitMillis:   The length of time in milliseconds the class will wait when DoEvents is called if there are no events to process.

If there are no events to process when DoEvents is called, the class will wait for the amount of time specified here before returning. The default value is 20.

UseInternalSecurityAPI:   Whether or not to use the system security libraries or an internal implementation.

When set to false, the class will use the system security libraries by default to perform cryptographic functions where applicable.

Setting this configuration setting to true tells the class to use the internal implementation instead of using the system security libraries.

On Windows, this setting is set to false by default. On Linux/macOS, this setting is set to true by default.

To use the system security libraries for Linux, OpenSSL support must be enabled. For more information on how to enable OpenSSL, please refer to the OpenSSL Notes section.

Trappable Errors (Gzip Class)

Error Handling (C++)

Call the GetLastErrorCode() method to obtain the last called method's result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. Known error codes are listed below. If an error occurs, the GetLastError() method can be called to retrieve the associated error message.

Errors

The following errors may be generated by the class. Note that frequently the error message will contain more specific information than what is listed here.

Note that some non-fatal errors may be trapped and explicitly ignored in the Error event. This will allow the class to continue operation even in case of error.

Gzip Errors

102   The gzip archive is of an invalid or unsupported format.
111   Can't open file for read.
112   Can't open file for write.
113   Can't create directory.
114   The file is too large.
115   Can't create empty archive.
116   The archive must be scanned prior to attempting this operation.
117   The array index is out of range.
118   The maximum size of the archive has been exceeded.
119   The archive must be specified, or streaming must be enabled.
120   The component is busy.
124   Must specify the compressed name.
127   Bad CRC-32 checksum.
128   Unable to set file date.
133   File already exists in the archive.
150   An I/O error has occurred (details follow).