Gzip C Reference Documentation
Gzip
Current Version: 11.0.0
GZip compression component.
Create/Dispose
HCkGzip instance = CkGzip_Create(); // ... CkGzip_Dispose(instance);
Creates an instance of the HCkGzip object and returns a handle ("void *" pointer). The handle is passed in the 1st argument for the functions listed on this page.
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
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.
See Also:C Example using Callback Functions
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.
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.
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
AbortCurrent
void CkGzip_putAbortCurrent(HCkGzip cHandle, BOOL newVal);
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.)
Comment
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.
topCompressionLevel
void CkGzip_putCompressionLevel(HCkGzip cHandle, int newVal);
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.
topDebugLogFilePath
void CkGzip_putDebugLogFilePath(HCkGzip cHandle, const char *newVal);
const char *CkGzip_debugLogFilePath(HCkGzip cHandle);
If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.
Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.
Possible causes of hangs include:
- A timeout property set to 0, indicating an infinite timeout.
- A hang occurring within an event callback in the application code.
- An internal bug in the Chilkat code causing the hang.
Filename
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.
topHeartbeatMs
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.
topLastErrorHtml
const char *CkGzip_lastErrorHtml(HCkGzip cHandle);
Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastErrorText
const char *CkGzip_lastErrorText(HCkGzip cHandle);
Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
LastErrorXml
const char *CkGzip_lastErrorXml(HCkGzip cHandle);
Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastMethodSuccess
void CkGzip_putLastMethodSuccess(HCkGzip cHandle, BOOL newVal);
Indicates the success or failure of the most recent method call: TRUE means success, FALSE means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages.
LastModStr
void CkGzip_putLastModStr(HCkGzip cHandle, const char *newVal);
const char *CkGzip_lastModStr(HCkGzip cHandle);
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. Uses the RFC822 string format.
topUseCurrentDate
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.
Utf8
void CkGzip_putUtf8(HCkGzip cHandle, BOOL newVal);
When set to TRUE, all const char * arguments and return values are interpreted as UTF-8 strings. When set to FALSE, they are interpreted as ANSI strings.
In Chilkat v11.0.0 and later, the default value is TRUE. Before v11.0.0, it was FALSE.
VerboseLogging
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.
Version
const char *CkGzip_version(HCkGzip cHandle);
Methods
CompressBd
In-place gzip the contents of binDat.
Returns TRUE for success, FALSE for failure.
CompressBdAsync (1)
Creates an asynchronous task to call the CompressBd method with the arguments provided.
Returns NULL on failure
CompressFile
Compresses a file to create a GZip compressed file (.gz).
Returns TRUE for success, FALSE for failure.
CompressFileAsync (1)
Creates an asynchronous task to call the CompressFile method with the arguments provided.
Returns NULL on failure
CompressFile2
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.
CompressFile2Async (1)
Creates an asynchronous task to call the CompressFile2 method with the arguments provided.
Returns NULL on failure
CompressFileBd
Gzip compresses a file into an in-memory .gz file stored in bd, with a maximum compressed size of 4GB.
Returns TRUE for success, FALSE for failure.
topCompressFileBdAsync (1)
Creates an asynchronous task to call the CompressFileBd method with the arguments provided.
Returns NULL on failure
CompressFileToMem Deprecated
Gzip compresses a file into an in-memory .gz image with a maximum size limit of 4GB.
Returns TRUE for success, FALSE for failure.
topCompressFileToMemAsync Deprecated (1)
Creates an asynchronous task to call the CompressFileToMem method with the arguments provided.
Returns NULL on failure
CompressMemory Deprecated
Compresses in-memory data to an in-memory image of a .gz file.
Note: There is a 4GB uncompressed size limitation. The uncompressed size of the file cannot be more than 4GB. Chilkat will be working to alleviate this limitation in the future.
Returns TRUE for success, FALSE for failure.
topCompressMemoryAsync Deprecated (1)
Creates an asynchronous task to call the CompressMemory method with the arguments provided.
Returns NULL on failure
CompressMemToFile Deprecated
Gzip compresses and creates a .gz file from in-memory data.
Returns TRUE for success, FALSE for failure.
topCompressMemToFileAsync Deprecated (1)
Creates an asynchronous task to call the CompressMemToFile method with the arguments provided.
Returns NULL on failure
CompressSb
Gzip compresses the byte representation of the string using the specified charset from charset (e.g., utf-8, iso-8859-1, or shift_JIS) and writes the compressed output to charset.
Returns TRUE for success, FALSE for failure.
topCompressSbAsync (1)
Creates an asynchronous task to call the CompressSb method with the arguments provided.
Returns NULL on failure
CompressString Deprecated
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.
CompressStringAsync Deprecated (1)
Creates an asynchronous task to call the CompressString method with the arguments provided.
Returns NULL on failure
CompressStringENC
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.
topCompressStringToFile
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.
CompressStringToFileAsync (1)
Creates an asynchronous task to call the CompressStringToFile method with the arguments provided.
Returns NULL on failure
Decode Deprecated
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.
topDeflateStringENC
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.
Encode Deprecated
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.
topExamineFile
Determines if the inGzFilename is a Gzip formatted file. Returns TRUE if it is a Gzip formatted file, otherwise returns FALSE.
ExamineMemory Deprecated
Determines if the in-memory bytes (inGzData) contain a Gzip formatted file. Returns TRUE if it is Gzip format, otherwise returns FALSE.
InflateStringENC
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.
topIsGzip
Checks if the data in bd is in Gzip format. Returns TRUE if it is, otherwise returns FALSE.
LoadTaskCaller
ReadFile Deprecated
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.
topSetDt
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.
topSetExtraData
Sets the optional extra data that can be included within a .gz when a Compress* method is called. The extra binary data is passed in encoded form, where the encoding can be base64, hex, or ascii if simple text.
Returns TRUE for success, FALSE for failure.
topUncompressBd
UncompressBdAsync (1)
Creates an asynchronous task to call the UncompressBd method with the arguments provided.
Returns NULL on failure
UncompressBdToFile
UncompressBdToFileAsync (1)
Creates an asynchronous task to call the UncompressBdToFile method with the arguments provided.
Returns NULL on failure
UncompressFile
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.
UncompressFileAsync (1)
Creates an asynchronous task to call the UncompressFile method with the arguments provided.
Returns NULL on failure
UncompressFileToMem Deprecated
Un-Gzips a .gz file directly to memory.
Note: There is a 4GB uncompressed size limitation. The uncompressed size of the file cannot be more than 4GB. Chilkat will be working to alleviate this limitation in the future.
Returns TRUE for success, FALSE for failure.
topUncompressFileToMemAsync Deprecated (1)
Creates an asynchronous task to call the UncompressFileToMem method with the arguments provided.
Returns NULL on failure
UncompressFileToString
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.
UncompressFileToStringAsync (1)
Creates an asynchronous task to call the UncompressFileToString method with the arguments provided.
Returns NULL on failure
UncompressMemory Deprecated
Un-Gzips from an in-memory image of a .gz file directly into memory.
Note: There is a 4GB uncompressed size limitation. The uncompressed size of the file cannot be more than 4GB. Chilkat will be working to alleviate this limitation in the future.
Returns TRUE for success, FALSE for failure.
topUncompressMemoryAsync Deprecated (1)
Creates an asynchronous task to call the UncompressMemory method with the arguments provided.
Returns NULL on failure
UncompressMemToFile Deprecated
Un-Gzips from an in-memory image of a .gz file to a file.
Returns TRUE for success, FALSE for failure.
topUncompressMemToFileAsync Deprecated (1)
Creates an asynchronous task to call the UncompressMemToFile method with the arguments provided.
Returns NULL on failure
UncompressString Deprecated
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.
UncompressStringAsync Deprecated (1)
Creates an asynchronous task to call the UncompressString method with the arguments provided.
Returns NULL on failure
UncompressStringENC
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.
topUnTarGz
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.
topUnTarGzAsync (1)
Creates an asynchronous task to call the UnTarGz method with the arguments provided.
Returns NULL on failure
WriteFile Deprecated
A convenience method for writing a binary byte array to a file.
Returns TRUE for success, FALSE for failure.
topXfdlToXml
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.
topDeprecated
GetDt
Applications should instead access the LastModStr property.
Gets the last-modification date/time to be embedded within the .gz.
Returns NULL on failure