Gzip C Reference Documentation

Gzip

GZip compression component.

Create/Dispose

HCkGzip CkGzip_Create(void);

Creates an instance of the HCkGzip object and returns a handle (i.e. a "void *" pointer). The handle is passed in the 1st argument for the functions listed on this page.

void CkGzip_Dispose(HCkGzip handle);

Objects created by calling CkGzip_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function. Also, any handle returned by a Chilkat "C" function must also be freed by the application by calling the appropriate Dispose method, such as CkGzip_Dispose.

Callback Functions

Callback Functions are Introduced in Chilkat v9.5.0.56

void CkGzip_setAbortCheck(HCkHttp cHandle, BOOL (*fnAbortCheck)());

Provides the opportunity for a method call to be aborted. If TRUE is returned, the operation in progress is aborted. Return FALSE to allow the current method call to continue. This callback function is called periodically based on the value of the HeartbeatMs property. (If HeartbeatMs is 0, then no callbacks are made.) As an example, to make 5 AbortCheck callbacks per second, set the HeartbeatMs property equal to 200.

C Example using Callback Functions

void CkGzip_setPercentDone(HCkHttp cHandle, BOOL (*fnPercentDone)(int pctDone));

Provides the percentage completed for any method that involves network communications or time-consuming processing (assuming it is a method where a percentage completion can be measured). This callback is only called when it is possible to know a percentage completion, and when it makes sense to express the operation as a percentage completed. The pctDone argument will have a value from 1 to 100. For methods that complete very quickly, the number of PercentDone callbacks will vary, but the final callback should have a value of 100. For long running operations, no more than one callback per percentage point will occur (for example: 1, 2, 3, ... 98, 99, 100).

This callback counts as an AbortCheck callback, and takes the place of the AbortCheck event when it fires.

The return value indicates whether the method call should be aborted, or whether it should proceed. Return TRUE to abort, and FALSE to proceed.

void CkGzip_setProgressInfo(HCkHttp cHandle, void (*fnProgressInfo)(const char *name, const char *value));

This is a general callback that provides name/value information about what is happening at certain points during a method call. To see the information provided in ProgressInfo callbacks, if any, write code to handle this event and log the name/value pairs. Most are self-explanatory.

void CkGzip_setTaskCompleted(HCkHttp cHandle, void (*fnTaskCompleted)(HCkTask hTask));

Called in the background thread when an asynchronous task completes. (Note: When an async method is running, all callbacks are in the background thread.)

Properties

BOOL CkGzip_getAbortCurrent(HCkGzip cHandle);

void CkGzip_putAbortCurrent(HCkGzip cHandle, BOOL newVal);

Introduced in version 9.5.0.58

When set to TRUE, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to FALSE when the next method is called. When the abort occurs, this property is reset to FALSE. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

void CkGzip_getComment(HCkGzip cHandle, HCkString retval);

void CkGzip_putComment(HCkGzip cHandle, const char *newVal);

const char *CkGzip_comment(HCkGzip cHandle);

Specifies an optional comment string that can be embedded within the .gz when any Compress* method is called.

int CkGzip_getCompressionLevel(HCkGzip cHandle);

void CkGzip_putCompressionLevel(HCkGzip cHandle, int newVal);

Introduced in version 9.5.0.50

The compression level to be used when compressing. The default is 6, which is the typical value used for zip utility programs when compressing data. The compression level may range from 0 (no compression) to 9 (the most compression). The benefits of trying to increase compression may not be worth the added expense in compression time. In many cases (which is data dependent), the improvement in compression is minimal while the increase in computation time is significant.

void CkGzip_getDebugLogFilePath(HCkGzip cHandle, HCkString retval);

void CkGzip_putDebugLogFilePath(HCkGzip cHandle, const char *newVal);

const char *CkGzip_debugLogFilePath(HCkGzip cHandle);

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

void CkGzip_getExtraData(HCkGzip cHandle, HCkByteData retval);

void CkGzip_putExtraData(HCkGzip cHandle, HCkByteData newVal);

Optional extra-data that can be included within a .gz when a Compress* method is called.

void CkGzip_getFilename(HCkGzip cHandle, HCkString retval);

void CkGzip_putFilename(HCkGzip cHandle, const char *newVal);

const char *CkGzip_filename(HCkGzip cHandle);

The filename that is embedded within the .gz during any Compress* method call. When extracting from a .gz using applications such as WinZip, this will be the filename that is created.

int CkGzip_getHeartbeatMs(HCkGzip cHandle);

void CkGzip_putHeartbeatMs(HCkGzip cHandle, int newVal);

The number of milliseconds between each AbortCheck event callback. The AbortCheck callback allows an application to abort any method call prior to completion. If HeartbeatMs is 0 (the default), no AbortCheck event callbacks will fire.

void CkGzip_getLastErrorHtml(HCkGzip cHandle, HCkString retval);

const char *CkGzip_lastErrorHtml(HCkGzip cHandle);

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

void CkGzip_getLastErrorText(HCkGzip cHandle, HCkString retval);

const char *CkGzip_lastErrorText(HCkGzip cHandle);

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

Concept of LastErrorText

LastErrorText Standard Information

void CkGzip_getLastErrorXml(HCkGzip cHandle, HCkString retval);

const char *CkGzip_lastErrorXml(HCkGzip cHandle);

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

BOOL CkGzip_getLastMethodSuccess(HCkGzip cHandle);

void CkGzip_putLastMethodSuccess(HCkGzip cHandle, BOOL newVal);

Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of TRUE indicates success, a value of FALSE indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = TRUE and failure = FALSE.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to TRUE. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

void CkGzip_getLastMod(HCkGzip cHandle, SYSTEMTIME * retval);

void CkGzip_putLastMod(HCkGzip cHandle, SYSTEMTIME *newVal);

This property is deprecated. It will be removed in a future version.

The last-modification date/time to be embedded within the .gz when a Compress* method is called. By default, the current system date/time is used.

void CkGzip_getLastModStr(HCkGzip cHandle, HCkString retval);

void CkGzip_putLastModStr(HCkGzip cHandle, const char *newVal);

const char *CkGzip_lastModStr(HCkGzip cHandle);

The same as the LastMod property, but allows the date/time to be get/set in RFC822 string format.

BOOL CkGzip_getUseCurrentDate(HCkGzip cHandle);

void CkGzip_putUseCurrentDate(HCkGzip cHandle, BOOL newVal);

If set to TRUE, the file produced by an Uncompress* method will use the current date/time for the last-modification date instead of the date/time found within the Gzip format.

BOOL CkGzip_getUtf8(HCkGzip cHandle);

void CkGzip_putUtf8(HCkGzip cHandle, BOOL newVal);

When set to TRUE, all "const char *" arguments are interpreted as utf-8 strings. If set to FALSE (the default), then "const char *" arguments are interpreted as ANSI strings. Also, when set to TRUE, and Chilkat method returning a "const char *" is returning the utf-8 representation. If set to FALSE, all "const char *" return values are ANSI strings.

BOOL CkGzip_getVerboseLogging(HCkGzip cHandle);

void CkGzip_putVerboseLogging(HCkGzip cHandle, BOOL newVal);

If set to TRUE, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is FALSE. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

void CkGzip_getVersion(HCkGzip cHandle, HCkString retval);

const char *CkGzip_version(HCkGzip cHandle);

Version of the component/library, such as "9.5.0.63"

Methods

BOOL CkGzip_CompressBd(HCkGzip cHandle, HCkBinData binDat);

Introduced in version 9.5.0.67

In-place gzip the contents of binDat.

Returns TRUE for success, FALSE for failure.

Gzip Compress In Memory and Base64 Encode

HCkTask CkGzip_CompressBdAsync(HCkGzip cHandle, HCkBinData binDat);

Introduced in version 9.5.0.67

Creates an asynchronous task to call the CompressBd method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_CompressFile(HCkGzip cHandle, const char *inFilename, const char *destPath);

Compresses a file to create a GZip compressed file (.gz).

Returns TRUE for success, FALSE for failure.

HCkTask CkGzip_CompressFileAsync(HCkGzip cHandle, const char *inFilename, const char *destPath);

Creates an asynchronous task to call the CompressFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_CompressFile2(HCkGzip cHandle, const char *inFilename, const char *embeddedFilename, const char *destPath);

Compresses a file to create a GZip compressed file (.gz). inFilename is the actual filename on disk. embeddedFilename is the filename to be embedded in the .gz such that when it is un-gzipped, this is the name of the file that will be created.

Returns TRUE for success, FALSE for failure.

HCkTask CkGzip_CompressFile2Async(HCkGzip cHandle, const char *inFilename, const char *embeddedFilename, const char *destPath);

Creates an asynchronous task to call the CompressFile2 method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_CompressFileToMem(HCkGzip cHandle, const char *inFilename, HCkByteData outData);

Gzip compresses a file to an in-memory image of a .gz file.

Returns TRUE for success, FALSE for failure.

HCkTask CkGzip_CompressFileToMemAsync(HCkGzip cHandle, const char *inFilename);

Creates an asynchronous task to call the CompressFileToMem method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_CompressMemory(HCkGzip cHandle, HCkByteData inData, HCkByteData outData);

Compresses in-memory data to an in-memory image of a .gz file.

Returns TRUE for success, FALSE for failure.

HCkTask CkGzip_CompressMemoryAsync(HCkGzip cHandle, HCkByteData inData);

Creates an asynchronous task to call the CompressMemory method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_CompressMemToFile(HCkGzip cHandle, HCkByteData inData, const char *destPath);

Gzip compresses and creates a .gz file from in-memory data.

Returns TRUE for success, FALSE for failure.

HCkTask CkGzip_CompressMemToFileAsync(HCkGzip cHandle, HCkByteData inData, const char *destPath);

Creates an asynchronous task to call the CompressMemToFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_CompressString(HCkGzip cHandle, const char *inStr, const char *destCharset, HCkByteData outBytes);

Gzip compresses a string and writes the output to a byte array. The string is first converted to the charset specified by destCharset. Typical charsets are "utf-8", "iso-8859-1", "shift_JIS", etc.

Returns TRUE for success, FALSE for failure.

Full List of Charset Names

HCkTask CkGzip_CompressStringAsync(HCkGzip cHandle, const char *inStr, const char *destCharset);

Creates an asynchronous task to call the CompressString method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_CompressStringENC(HCkGzip cHandle, const char *inStr, const char *charset, const char *encoding, HCkString outStr);

const char *CkGzip_compressStringENC(HCkGzip cHandle, const char *inStr, const char *charset, const char *encoding);

The same as CompressString, except the binary output is returned in encoded string form according to the encoding. The encoding can be any of the following: "Base64", "modBase64", "Base32", "UU", "QP" (for quoted-printable), "URL" (for url-encoding), "Hex", "Q", "B", "url_oath", "url_rfc1738", "url_rfc2396", and "url_rfc3986".

Returns TRUE for success, FALSE for failure.

BOOL CkGzip_CompressStringToFile(HCkGzip cHandle, const char *inStr, const char *destCharset, const char *destPath);

Gzip compresses a string and writes the output to a .gz compressed file. The string is first converted to the charset specified by destCharset. Typical charsets are "utf-8", "iso-8859-1", "shift_JIS", etc.

Returns TRUE for success, FALSE for failure.

Full List of Charset Names

HCkTask CkGzip_CompressStringToFileAsync(HCkGzip cHandle, const char *inStr, const char *destCharset, const char *destPath);

Creates an asynchronous task to call the CompressStringToFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_Decode(HCkGzip cHandle, const char *encodedStr, const char *encoding, HCkByteData outBytes);

Decodes an encoded string and returns the original data. The encoding mode is determined by encoding. It may be "base64", "hex", "quoted-printable", or "url".

Returns TRUE for success, FALSE for failure.

BOOL CkGzip_DeflateStringENC(HCkGzip cHandle, const char *inString, const char *charsetName, const char *outputEncoding, HCkString outStr);

const char *CkGzip_deflateStringENC(HCkGzip cHandle, const char *inString, const char *charsetName, const char *outputEncoding);

Provides the ability to use the zip/gzip's deflate algorithm directly to compress a string. Internal to this method, inString is first converted to the charset specified by charsetName. The data is then compressed using the deflate compression algorithm. The binary output is then encoded according to outputEncoding. Possible values for outputEncoding are "hex", "base64", "url", and "quoted-printable".

Note: The output of this method is compressed data with no Gzip file format. Use the Compress* methods to produce Gzip file format output.

Returns TRUE for success, FALSE for failure.

Full List of Charset Names

BOOL CkGzip_Encode(HCkGzip cHandle, HCkByteData byteData, const char *encoding, HCkString outStr);

const char *CkGzip_encode(HCkGzip cHandle, HCkByteData byteData, const char *encoding);

Encodes binary data to a printable string. The encoding mode is determined by encoding. It may be "base64", "hex", "quoted-printable", or "url".

Returns TRUE for success, FALSE for failure.

BOOL CkGzip_ExamineFile(HCkGzip cHandle, const char *inGzFilename);

Determines if the inGzFilename is a Gzip formatted file. Returns TRUE if it is a Gzip formatted file, otherwise returns FALSE.

BOOL CkGzip_ExamineMemory(HCkGzip cHandle, HCkByteData inGzData);

Determines if the in-memory bytes (inGzData) contain a Gzip formatted file. Returns TRUE if it is Gzip format, otherwise returns FALSE.

HCkDateTime CkGzip_GetDt(HCkGzip cHandle);

Gets the last-modification date/time to be embedded within the .gz.

Returns NULL on failure

BOOL CkGzip_InflateStringENC(HCkGzip cHandle, const char *inString, const char *convertFromCharset, const char *inputEncoding, HCkString outStr);

const char *CkGzip_inflateStringENC(HCkGzip cHandle, const char *inString, const char *convertFromCharset, const char *inputEncoding);

This the reverse of DeflateStringENC.

The input string is first decoded according to inputEncoding. (Possible values for inputEncoding are "hex", "base64", "url", and "quoted-printable".) The compressed data is then inflated, and the result is then converted from convertFromCharset (if necessary) to return a string.

Returns TRUE for success, FALSE for failure.

BOOL CkGzip_IsUnlocked(HCkGzip cHandle);

Returns TRUE if the component has been unlocked.

BOOL CkGzip_ReadFile(HCkGzip cHandle, const char *path, HCkByteData outBytes);

Reads a binary file into memory and returns the byte array. Note: This method does not parse a Gzip, it is only a convenience method for reading a binary file into memory.

Returns TRUE for success, FALSE for failure.

BOOL CkGzip_SaveLastError(HCkGzip cHandle, const char *path);

Saves the last-error information (the contents of LastErrorXml) to an XML formatted file.

Returns TRUE for success, FALSE for failure.

BOOL CkGzip_SetDt(HCkGzip cHandle, HCkDateTime dt);

Sets the last-modification date/time to be embedded within the .gz when a Compress* method is called. If not explicitly set, the current system date/time is used.

Returns TRUE for success, FALSE for failure.

BOOL CkGzip_UncompressBd(HCkGzip cHandle, HCkBinData binDat);

Introduced in version 9.5.0.67

In-place ungzip the contents of binDat.

Returns TRUE for success, FALSE for failure.

HCkTask CkGzip_UncompressBdAsync(HCkGzip cHandle, HCkBinData binDat);

Introduced in version 9.5.0.67

Creates an asynchronous task to call the UncompressBd method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_UncompressFile(HCkGzip cHandle, const char *srcPath, const char *destPath);

Un-Gzips a .gz file. The output filename is specified by the 2nd argument and not by the filename embedded within the .gz.

Returns TRUE for success, FALSE for failure.

GZip Decompress File

HCkTask CkGzip_UncompressFileAsync(HCkGzip cHandle, const char *srcPath, const char *destPath);

Creates an asynchronous task to call the UncompressFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_UncompressFileToMem(HCkGzip cHandle, const char *inFilename, HCkByteData outData);

Un-Gzips a .gz file directly to memory.

Returns TRUE for success, FALSE for failure.

HCkTask CkGzip_UncompressFileToMemAsync(HCkGzip cHandle, const char *inFilename);

Creates an asynchronous task to call the UncompressFileToMem method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_UncompressFileToString(HCkGzip cHandle, const char *gzFilename, const char *charset, HCkString outStr);

const char *CkGzip_uncompressFileToString(HCkGzip cHandle, const char *gzFilename, const char *charset);

Uncompresses a .gz file that contains a text file. The contents of the text file are returned as a string. The character encoding of the text file is specified by charset. Typical charsets are "iso-8859-1", "utf-8", "windows-1252", "shift_JIS", "big5", etc.

Returns TRUE for success, FALSE for failure.

List of Valid Charsets

HCkTask CkGzip_UncompressFileToStringAsync(HCkGzip cHandle, const char *gzFilename, const char *charset);

Creates an asynchronous task to call the UncompressFileToString method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_UncompressMemory(HCkGzip cHandle, HCkByteData inData, HCkByteData outData);

Un-Gzips from an in-memory image of a .gz file directly into memory.

Returns TRUE for success, FALSE for failure.

HCkTask CkGzip_UncompressMemoryAsync(HCkGzip cHandle, HCkByteData inData);

Creates an asynchronous task to call the UncompressMemory method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_UncompressMemToFile(HCkGzip cHandle, HCkByteData inData, const char *destPath);

Un-Gzips from an in-memory image of a .gz file to a file.

Returns TRUE for success, FALSE for failure.

HCkTask CkGzip_UncompressMemToFileAsync(HCkGzip cHandle, HCkByteData inData, const char *destPath);

Creates an asynchronous task to call the UncompressMemToFile method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_UncompressString(HCkGzip cHandle, HCkByteData inData, const char *inCharset, HCkString outStr);

const char *CkGzip_uncompressString(HCkGzip cHandle, HCkByteData inData, const char *inCharset);

The reverse of CompressString.

The bytes in inData are uncompressed, then converted from inCharset (if necessary) to return a string.

Returns TRUE for success, FALSE for failure.

Full List of Charset Names

HCkTask CkGzip_UncompressStringAsync(HCkGzip cHandle, HCkByteData inData, const char *inCharset);

Creates an asynchronous task to call the UncompressString method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_UncompressStringENC(HCkGzip cHandle, const char *inStr, const char *charset, const char *encoding, HCkString outStr);

const char *CkGzip_uncompressStringENC(HCkGzip cHandle, const char *inStr, const char *charset, const char *encoding);

The same as UncompressString, except the compressed data is provided in encoded string form based on the value of encoding. The encoding can be "Base64", "modBase64", "Base32", "UU", "QP" (for quoted-printable), "URL" (for url-encoding), "Hex", "Q", "B", "url_oath", "url_rfc1738", "url_rfc2396", and "url_rfc3986".

Returns TRUE for success, FALSE for failure.

BOOL CkGzip_UnlockComponent(HCkGzip cHandle, const char *unlockCode);

Unlocks the component allowing for the full functionality to be used.

Returns TRUE for success, FALSE for failure.

Diagnosing UnlockComponent Problems

UnlockComponent LastErrorText shows exact string passed to it.

Verify UnlockComponent Success w/ Purchased Unlock Code

LastErrorText Standard Information

BOOL CkGzip_UnTarGz(HCkGzip cHandle, const char *tgzFilename, const char *destDir, BOOL bNoAbsolute);

Unpacks a .tar.gz file. The ungzip and untar occur in streaming mode. There are no temporary files and the memory footprint is constant (and small) while untarring. bNoAbsolute may be TRUE or FALSE. A value of TRUE protects from untarring to absolute paths. (For example, imagine the trouble if the tar contains files with absolute paths beginning with /Windows/system32)

Returns TRUE for success, FALSE for failure.

HCkTask CkGzip_UnTarGzAsync(HCkGzip cHandle, const char *tgzFilename, const char *destDir, BOOL bNoAbsolute);

Creates an asynchronous task to call the UnTarGz method with the arguments provided. (Async methods are available starting in Chilkat v9.5.0.52.)

Returns NULL on failure

How to Run an Asynchronous Task

BOOL CkGzip_WriteFile(HCkGzip cHandle, const char *path, HCkByteData binaryData);

A convenience method for writing a binary byte array to a file.

Returns TRUE for success, FALSE for failure.

BOOL CkGzip_XfdlToXml(HCkGzip cHandle, const char *xfldData, HCkString outStr);

const char *CkGzip_xfdlToXml(HCkGzip cHandle, const char *xfldData);

Converts base64-gzip .xfdl data to a decompressed XML string. The xfldData contains the base64 data. This method returns the decoded/decompressed XML string.

Returns TRUE for success, FALSE for failure.