Gzip Objective-C Reference Documentation

CkoGzip

Current Version: 11.1.0

GZip compression component.

Object Creation

CkoGzip *obj = [[CkoGzip alloc] init];

Properties

AbortCurrent
@property (nonatomic) BOOL AbortCurrent;
Introduced in version 9.5.0.58

When set to YES, 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 NO when the next method is called. When the abort occurs, this property is reset to NO. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

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Comment
@property (nonatomic, copy) NSString *Comment;

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

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CompressionLevel
@property (nonatomic, copy) NSNumber *CompressionLevel;
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.

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DebugLogFilePath
@property (nonatomic, copy) NSString *DebugLogFilePath;

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.

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Filename
@property (nonatomic, copy) NSString *Filename;

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.

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HeartbeatMs
@property (nonatomic, copy) NSNumber *HeartbeatMs;

The interval in milliseconds between each AbortCheck event callback, which enables an application to abort certain method calls before they complete. By default, HeartbeatMs is set to 0, meaning no AbortCheck event callbacks will trigger.

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LastErrorHtml
@property (nonatomic, readonly, copy) NSString *LastErrorHtml;

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.

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LastErrorText
@property (nonatomic, readonly, copy) NSString *LastErrorText;

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.

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LastErrorXml
@property (nonatomic, readonly, copy) NSString *LastErrorXml;

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.

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LastMethodSuccess
@property (nonatomic) BOOL LastMethodSuccess;

Indicates the success or failure of the most recent method call: YES means success, NO 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.

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LastModStr
@property (nonatomic, copy) NSString *LastModStr;

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.

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UseCurrentDate
@property (nonatomic) BOOL UseCurrentDate;

If set to YES, 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.

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VerboseLogging
@property (nonatomic) BOOL VerboseLogging;

If set to YES, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is NO. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
@property (nonatomic, readonly, copy) NSString *Version;

Version of the component/library, such as "10.1.0"

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Methods

CompressBd
- (BOOL)CompressBd:(CkoBinData *)binDat;
Introduced in version 9.5.0.67

In-place gzip the contents of binDat.

Returns YES for success, NO for failure.

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CompressBdAsync (1)
- (CkoTask *)CompressBdAsync:(CkoBinData *)binDat;
Introduced in version 9.5.0.67

Creates an asynchronous task to call the CompressBd method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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CompressFile
- (BOOL)CompressFile:(NSString *)srcPath
    destPath:(NSString *)destPath;

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

Returns YES for success, NO for failure.

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CompressFileAsync (1)
- (CkoTask *)CompressFileAsync:(NSString *)srcPath
    destPath:(NSString *)destPath;

Creates an asynchronous task to call the CompressFile method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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CompressFile2
- (BOOL)CompressFile2:(NSString *)srcPath
    embeddedFilename:(NSString *)embeddedFilename
    destPath:(NSString *)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 YES for success, NO for failure.

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CompressFile2Async (1)
- (CkoTask *)CompressFile2Async:(NSString *)srcPath
    embeddedFilename:(NSString *)embeddedFilename
    destPath:(NSString *)destPath;

Creates an asynchronous task to call the CompressFile2 method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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CompressFileBd
- (BOOL)CompressFileBd:(NSString *)filePath
    bd:(CkoBinData *)bd;
Introduced in version 11.0.0

Gzip compresses a file into an in-memory .gz file stored in bd, with a maximum compressed size of 4GB.

Returns YES for success, NO for failure.

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CompressFileBdAsync (1)
- (CkoTask *)CompressFileBdAsync:(NSString *)filePath
    bd:(CkoBinData *)bd;
Introduced in version 11.0.0

Creates an asynchronous task to call the CompressFileBd method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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CompressFileToMem
- (NSData *)CompressFileToMem:(NSString *)srcPath;

Gzip compresses a file into an in-memory .gz image with a maximum size limit of 4GB.

Returns nil on failure

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CompressFileToMemAsync (1)
- (CkoTask *)CompressFileToMemAsync:(NSString *)srcPath;

Creates an asynchronous task to call the CompressFileToMem method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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CompressMemory
- (NSData *)CompressMemory:(NSData *)dbIn;

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 nil on failure

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CompressMemoryAsync (1)
- (CkoTask *)CompressMemoryAsync:(NSData *)dbIn;

Creates an asynchronous task to call the CompressMemory method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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CompressMemToFile
- (BOOL)CompressMemToFile:(NSData *)db
    destPath:(NSString *)destPath;

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

Returns YES for success, NO for failure.

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CompressMemToFileAsync (1)
- (CkoTask *)CompressMemToFileAsync:(NSData *)db
    destPath:(NSString *)destPath;

Creates an asynchronous task to call the CompressMemToFile method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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CompressSb
- (BOOL)CompressSb:(CkoStringBuilder *)sb
    charset:(NSString *)charset
    bd:(CkoBinData *)bd;
Introduced in version 11.0.0

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 YES for success, NO for failure.

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CompressSbAsync (1)
- (CkoTask *)CompressSbAsync:(CkoStringBuilder *)sb
    charset:(NSString *)charset
    bd:(CkoBinData *)bd;
Introduced in version 11.0.0

Creates an asynchronous task to call the CompressSb method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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CompressString
- (NSData *)CompressString:(NSString *)inStr
    destCharset:(NSString *)destCharset;

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 nil on failure

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CompressStringAsync (1)
- (CkoTask *)CompressStringAsync:(NSString *)inStr
    destCharset:(NSString *)destCharset;

Creates an asynchronous task to call the CompressString method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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CompressStringENC
- (NSString *)CompressStringENC:(NSString *)strIn
    charset:(NSString *)charset
    encoding:(NSString *)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 nil on failure

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CompressStringToFile
- (BOOL)CompressStringToFile:(NSString *)inStr
    destCharset:(NSString *)destCharset
    destPath:(NSString *)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 YES for success, NO for failure.

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CompressStringToFileAsync (1)
- (CkoTask *)CompressStringToFileAsync:(NSString *)inStr
    destCharset:(NSString *)destCharset
    destPath:(NSString *)destPath;

Creates an asynchronous task to call the CompressStringToFile method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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Decode
- (NSData *)Decode:(NSString *)str
    encoding:(NSString *)encoding;

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 nil on failure

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DeflateStringENC
- (NSString *)DeflateStringENC:(NSString *)str
    charset:(NSString *)charset
    encoding:(NSString *)encoding;

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 nil on failure

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Encode
- (NSString *)Encode:(NSData *)byteData
    encoding:(NSString *)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 nil on failure

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ExamineFile
- (BOOL)ExamineFile:(NSString *)inGzPath;

Determines if the inGzFilename is a Gzip formatted file. Returns YES if it is a Gzip formatted file, otherwise returns NO.

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ExamineMemory
- (BOOL)ExamineMemory:(NSData *)inGzData;

Determines if the in-memory bytes (inGzData) contain a Gzip formatted file. Returns YES if it is Gzip format, otherwise returns NO.

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InflateStringENC
- (NSString *)InflateStringENC:(NSString *)str
    charset:(NSString *)charset
    encoding:(NSString *)encoding;

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 nil on failure

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IsGzip
- (BOOL)IsGzip:(CkoBinData *)bd;
Introduced in version 11.0.0

Checks if the data in bd is in Gzip format. Returns YES if it is, otherwise returns NO.

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LoadTaskCaller
- (BOOL)LoadTaskCaller:(CkoTask *)task;
Introduced in version 9.5.0.80

Loads the caller of the task's async method.

Returns YES for success, NO for failure.

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ReadFile
- (NSData *)ReadFile:(NSString *)path;

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 nil on failure

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SetDt
- (BOOL)SetDt:(CkoDateTime *)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 YES for success, NO for failure.

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SetExtraData
- (BOOL)SetExtraData:(NSString *)encodedData
    encoding:(NSString *)encoding;
Introduced in version 11.0.0

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 YES for success, NO for failure.

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UncompressBd
- (BOOL)UncompressBd:(CkoBinData *)binDat;
Introduced in version 9.5.0.67

In-place ungzip the contents of binDat.

Returns YES for success, NO for failure.

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UncompressBdAsync (1)
- (CkoTask *)UncompressBdAsync:(CkoBinData *)binDat;
Introduced in version 9.5.0.67

Creates an asynchronous task to call the UncompressBd method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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UncompressBdToFile
- (BOOL)UncompressBdToFile:(CkoBinData *)bd
    filePath:(NSString *)filePath;
Introduced in version 11.0.0

Un-Gzips from a GZip stored in bd to a file.

Returns YES for success, NO for failure.

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UncompressBdToFileAsync (1)
- (CkoTask *)UncompressBdToFileAsync:(CkoBinData *)bd
    filePath:(NSString *)filePath;
Introduced in version 11.0.0

Creates an asynchronous task to call the UncompressBdToFile method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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UncompressFile
- (BOOL)UncompressFile:(NSString *)srcPath
    destPath:(NSString *)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 YES for success, NO for failure.

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UncompressFileAsync (1)
- (CkoTask *)UncompressFileAsync:(NSString *)srcPath
    destPath:(NSString *)destPath;

Creates an asynchronous task to call the UncompressFile method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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UncompressFileToMem
- (NSData *)UncompressFileToMem:(NSString *)srcPath;

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 nil on failure

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UncompressFileToMemAsync (1)
- (CkoTask *)UncompressFileToMemAsync:(NSString *)srcPath;

Creates an asynchronous task to call the UncompressFileToMem method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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UncompressFileToString
- (NSString *)UncompressFileToString:(NSString *)srcPath
    inCharset:(NSString *)inCharset;

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 nil on failure

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UncompressFileToStringAsync (1)
- (CkoTask *)UncompressFileToStringAsync:(NSString *)srcPath
    inCharset:(NSString *)inCharset;

Creates an asynchronous task to call the UncompressFileToString method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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UncompressMemory
- (NSData *)UncompressMemory:(NSData *)dbIn;

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 nil on failure

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UncompressMemoryAsync (1)
- (CkoTask *)UncompressMemoryAsync:(NSData *)dbIn;

Creates an asynchronous task to call the UncompressMemory method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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UncompressMemToFile
- (BOOL)UncompressMemToFile:(NSData *)db
    destPath:(NSString *)destPath;

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

Returns YES for success, NO for failure.

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UncompressMemToFileAsync (1)
- (CkoTask *)UncompressMemToFileAsync:(NSData *)db
    destPath:(NSString *)destPath;

Creates an asynchronous task to call the UncompressMemToFile method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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UncompressString
- (NSString *)UncompressString:(NSData *)inData
    inCharset:(NSString *)inCharset;

The reverse of CompressString.

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

Returns nil on failure

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UncompressStringAsync (1)
- (CkoTask *)UncompressStringAsync:(NSData *)inData
    inCharset:(NSString *)inCharset;

Creates an asynchronous task to call the UncompressString method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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UncompressStringENC
- (NSString *)UncompressStringENC:(NSString *)strIn
    charset:(NSString *)charset
    encoding:(NSString *)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 nil on failure

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UnTarGz
- (BOOL)UnTarGz:(NSString *)gzPath
    destDir:(NSString *)destDir
    bNoAbsolute:(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 YES or NO. A value of YES protects from untarring to absolute paths. (For example, imagine the trouble if the tar contains files with absolute paths beginning with /Windows/system32)

Returns YES for success, NO for failure.

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UnTarGzAsync (1)
- (CkoTask *)UnTarGzAsync:(NSString *)gzPath
    destDir:(NSString *)destDir
    bNoAbsolute:(BOOL)bNoAbsolute;

Creates an asynchronous task to call the UnTarGz method with the arguments provided.

Note: Async method event callbacks happen in the background thread. Accessing and updating UI elements existing in the main thread may require special considerations.

Returns nil on failure

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WriteFile
- (BOOL)WriteFile:(NSString *)path
    binaryData:(NSData *)binaryData;

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

Returns YES for success, NO for failure.

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XfdlToXml
- (NSString *)XfdlToXml:(NSString *)xfdl;

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 nil on failure

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Events

To implement an event callback, your application would define and implement a class that inherits from CkoBaseProgress. Your application can implement methods to override some or all of the default/empty method implementations of the CkoBaseProgress base class.

For example:

  CkoGzip *gzip = [[CkoGzip alloc] init];

  MyGzipProgress *callbackObj = [[MyGzipProgress alloc] init];

  [gzip setEventCallbackObject:callbackObj];

MyGzipProgress interface example:

#import "CkoGzipProgress.h"

@interface MyGzipProgress : CkoBaseProgress {

}

    - (id)init;
    - (void)dealloc;
    - (void)dispose;

    - (void)AbortCheck:(BOOL *)abort;

    - (void)PercentDone:(NSNumber *)pctDone 
        abort:(BOOL *)abort;

    - (void)ProgressInfo:(NSString *)name 
        value:(NSString *)value;

    - (void)TaskCompleted:(CkoTask *)task;

@end
AbortCheck
- (void)AbortCheck:(BOOL *)abort;

Enables a method call to be aborted by triggering the AbortCheck event at intervals defined by the HeartbeatMs property. If HeartbeatMs is set to its default value of 0, no events will occur. For instance, set HeartbeatMs to 200 to trigger 5 AbortCheck events per second.

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PercentDone
- (void)PercentDone:(NSNumber *)pctDone
    abort:(BOOL *)abort;

This provides the percentage completion for any method involving network communications or time-consuming processing, assuming the progress can be measured as a percentage. This event is triggered only when it's possible and logical to express the operation's progress as a percentage. The pctDone argument will range from 1 to 100. For methods that finish quickly, the number of PercentDone callbacks may vary, but the final callback will have pctDone equal to 100. For longer operations, callbacks will not exceed one per percentage point (e.g., 1, 2, 3, ..., 98, 99, 100).

The PercentDone callback also acts as an AbortCheck event. For fast methods where PercentDone fires, an AbortCheck event may not trigger since the PercentDone callback already provides an opportunity to abort. For longer operations, where time between PercentDone callbacks is extended, AbortCheck callbacks enable more responsive operation termination.

To abort the operation, set the abort output argument to YES. This will cause the method to terminate and return a failure status or corresponding failure value.

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ProgressInfo
- (void)ProgressInfo:(NSString *)name
    value:(NSString *)value;

This event callback provides tag name/value pairs that detail what occurs during a method call. To discover existing tag names, create code to handle the event, emit the pairs, and review them. Most tag names are self-explanatory.

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TaskCompleted
- (void)TaskCompleted:(CkoTask *)task;

Called from the background thread when an asynchronous task completes.

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Deprecated

GetDt
- (CkoDateTime *)GetDt;
This method is deprecated.

Applications should instead access the LastModStr property.

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

Returns nil on failure

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