ZCompress Class

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The ZCompress class implements an LZC compressor and decompressor. It is compatible with the UNIX compress utility.

Syntax

ZCompress

Remarks

The LZC file format is 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 LZC compressed 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 based on the ArchiveFile name. Finally, invoke the Extract method.

Example (Creating an LZC File)

ZipControl.ArchiveFile = "c:\test.Z" ZipControl.FileDecompressedName = "c:\test.txt" ZipControl.Compress() Example (Extracting from an LZC File)

ZipControl.ArchiveFile = "c:\test.Z" 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.

Method List

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

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.

Config Settings

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

ArchiveFile Property (ZCompress Class)

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

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
char* GetArchiveFile();
int SetArchiveFile(const char* lpszArchiveFile);

Unicode (Windows)
LPWSTR GetArchiveFile();
INT SetArchiveFile(LPCWSTR lpszArchiveFile);

char* ipworkszip_zcompress_getarchivefile(void* lpObj);
int ipworkszip_zcompress_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

FileDecompressedName Property (ZCompress Class)

File name to decompress to, or compress from.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
char* GetFileDecompressedName();
int SetFileDecompressedName(const char* lpszFileDecompressedName);

Unicode (Windows)
LPWSTR GetFileDecompressedName();
INT SetFileDecompressedName(LPCWSTR lpszFileDecompressedName);

char* ipworkszip_zcompress_getfiledecompressedname(void* lpObj);
int ipworkszip_zcompress_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 and SetFileInputStream has not been called with a valid input stream, 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 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.

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

FileInputData Property (ZCompress Class)

The data of the file to be compressed.

Syntax

• C++
• C
• Qt

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_zcompress_getfileinputdata(void* lpObj, char** lpFileInputData, int* lenFileInputData);
int ipworkszip_zcompress_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

ZCompressData Property (ZCompress Class)

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

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int SetZCompressData(const char* lpZCompressData, int lenZCompressData);

Unicode (Windows)
INT SetZCompressData(LPCSTR lpZCompressData, INT lenZCompressData);

int ipworkszip_zcompress_setzcompressdata(void* lpObj, const char* lpZCompressData, int lenZCompressData);

int SetZCompressData(QByteArray qbaZCompressData);

Default Value

""

Remarks

Normally you should set ArchiveFile before invoking Extract. If you prefer to read the LZC compressed file from memory you may set ZCompressData instead. ZCompressData should be set to the entire contents of the LZC compressed 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 you should set the value of FileDecompressedName to an empty string. Then, when you invoke Extract the data will be provided in the Progress event.

This property is write-only. Note that modifying a LZC compressed file stored in ZCompressData is not supported.

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

Data Type

Binary String

Abort Method (ZCompress Class)

Aborts the current operation.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int Abort();

Unicode (Windows)
INT Abort();

int ipworkszip_zcompress_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.)

Compress Method (ZCompress Class)

Creates the compressed archive.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int Compress();

Unicode (Windows)
INT Compress();

int ipworkszip_zcompress_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.

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 (ZCompress Class)

Sets or retrieves a configuration setting.

Syntax

• C++
• C
• Qt

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

Unicode (Windows)
LPWSTR Config(LPCWSTR lpszConfigurationString);

char* ipworkszip_zcompress_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 (ZCompress Class)

Extracts the compressed file from the archive.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int Extract();

Unicode (Windows)
INT Extract();

int ipworkszip_zcompress_extract(void* lpObj);

int Extract();

Remarks

Invoking Extract decompresses the archive specified by ArchiveFile. The compressed file will be extracted, and written to disk.

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 FileDecompressedName is empty and ArchiveFile ends in ".Z", this filename, less the ".Z" extension will be used. Otherwise the extension ".uncompressed" will be appended to the file name.

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 (ZCompress Class)

Resets the class.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
int Reset();

Unicode (Windows)
INT Reset();

int ipworkszip_zcompress_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.)

SetArchiveInputStream Method (ZCompress Class)

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

Syntax

• C++
• C
• Qt

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

Unicode (Windows)
INT SetArchiveInputStream(IPWorksZipStream* sArchiveStream);

int ipworkszip_zcompress_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 (ZCompress Class)

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

Syntax

• C++
• C
• Qt

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

Unicode (Windows)
INT SetArchiveOutputStream(IPWorksZipStream* sArchiveStream);

int ipworkszip_zcompress_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.)

BeginFile Event (ZCompress Class)

Fired before a file is processed.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
virtual int FireBeginFile(ZCompressBeginFileEventParams *e);

typedef struct {
  int Index;
  int Skip;
  int reserved;
} ZCompressBeginFileEventParams;


Unicode (Windows)
virtual INT FireBeginFile(ZCompressBeginFileEventParams *e);

typedef struct {
  INT Index;
  BOOL Skip;
  INT reserved;
} ZCompressBeginFileEventParams;

#define EID_ZCOMPRESS_BEGINFILE 1

virtual INT IPWORKSZIP_CALL FireBeginFile(INT &iIndex, BOOL &bSkip);

class ZCompressBeginFileEventParams {
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(ZCompressBeginFileEventParams *e);

// Or, subclass ZCompress and override this emitter function.
virtual int FireBeginFile(ZCompressBeginFileEventParams *e) {...}

Remarks

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

You may use the Skip parameter to tell the component to skip the file when compressing or decompressing.

EndFile Event (ZCompress Class)

Fired after a file is processed.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
virtual int FireEndFile(ZCompressEndFileEventParams *e);

typedef struct {
  int Index;
  int reserved;
} ZCompressEndFileEventParams;


Unicode (Windows)
virtual INT FireEndFile(ZCompressEndFileEventParams *e);

typedef struct {
  INT Index;
  INT reserved;
} ZCompressEndFileEventParams;

#define EID_ZCOMPRESS_ENDFILE 2

virtual INT IPWORKSZIP_CALL FireEndFile(INT &iIndex);

class ZCompressEndFileEventParams {
public:
  int Index();

  int EventRetVal();
  void SetEventRetVal(int iRetVal);
};

// To handle, connect one or more slots to this signal.
void EndFile(ZCompressEndFileEventParams *e);

// Or, subclass ZCompress and override this emitter function.
virtual int FireEndFile(ZCompressEndFileEventParams *e) {...}

Remarks

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

Error Event (ZCompress Class)

Information about non-fatal errors.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
virtual int FireError(ZCompressErrorEventParams *e);

typedef struct {
  const char *Description;
  int ErrorCode;
  int Index;
  const char *Filename;
  int Ignore;
  int reserved;
} ZCompressErrorEventParams;


Unicode (Windows)
virtual INT FireError(ZCompressErrorEventParams *e);

typedef struct {
  LPCWSTR Description;
  INT ErrorCode;
  INT Index;
  LPCWSTR Filename;
  BOOL Ignore;
  INT reserved;
} ZCompressErrorEventParams;

#define EID_ZCOMPRESS_ERROR 3

virtual INT IPWORKSZIP_CALL FireError(LPSTR &lpszDescription, INT &iErrorCode, INT &iIndex, LPSTR &lpszFilename, BOOL &bIgnore);

class ZCompressErrorEventParams {
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(ZCompressErrorEventParams *e);

// Or, subclass ZCompress and override this emitter function.
virtual int FireError(ZCompressErrorEventParams *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:

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 (ZCompress Class)

Fired whenever a file exists and may be overwritten.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
virtual int FireOverwrite(ZCompressOverwriteEventParams *e);

typedef struct {
  char *Filename;
  int Overwrite;
  int reserved;
} ZCompressOverwriteEventParams;


Unicode (Windows)
virtual INT FireOverwrite(ZCompressOverwriteEventParams *e);

typedef struct {
  LPWSTR Filename;
  BOOL Overwrite;
  INT reserved;
} ZCompressOverwriteEventParams;

#define EID_ZCOMPRESS_OVERWRITE 4

virtual INT IPWORKSZIP_CALL FireOverwrite(LPSTR &lpszFilename, BOOL &bOverwrite);

class ZCompressOverwriteEventParams {
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(ZCompressOverwriteEventParams *e);

// Or, subclass ZCompress and override this emitter function.
virtual int FireOverwrite(ZCompressOverwriteEventParams *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 (ZCompress Class)

Fired as progress is made.

Syntax

• C++
• C
• Qt

ANSI (Cross Platform)
virtual int FireProgress(ZCompressProgressEventParams *e);

typedef struct {
  const char *Data;
  int lenData;
  const char *Filename;
  int64 BytesProcessed;
  int PercentProcessed;
  int reserved;
} ZCompressProgressEventParams;


Unicode (Windows)
virtual INT FireProgress(ZCompressProgressEventParams *e);

typedef struct {
  LPCSTR Data;
  INT lenData;
  LPCWSTR Filename;
  LONG64 BytesProcessed;
  INT PercentProcessed;
  INT reserved;
} ZCompressProgressEventParams;

#define EID_ZCOMPRESS_PROGRESS 5

virtual INT IPWORKSZIP_CALL FireProgress(LPSTR &lpData, INT &lenData, LPSTR &lpszFilename, LONG64 &lBytesProcessed, INT &iPercentProcessed);

class ZCompressProgressEventParams {
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(ZCompressProgressEventParams *e);

// Or, subclass ZCompress and override this emitter function.
virtual int FireProgress(ZCompressProgressEventParams *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 ZCompress 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 ZCompress 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.

bool CanRead() { return true; }

bool CanSeek() { return true; }

bool CanWrite() { return true; }

int64 GetLength() = 0;

void Close() {}

int Flush() { return 0; }

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

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

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

Config Settings (ZCompress Class)

ZCompress Config Settings

Base Config Settings

Trappable Errors (ZCompress 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.

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.

ZCompress Errors