Gzip Ruby Reference Documentation

CkGzip

Current Version: 11.4.0

This class provides functionality for working with GZIP compression in both file-based and in-memory scenarios. It supports compressing and decompressing:

  • Files (.gz, .tar.gz)
  • Strings (with charset conversion)
  • Binary data (byte[], BinData)
  • Encoded data (Base64, Hex, etc.)

It also allows embedding metadata such as filenames, timestamps, and comments within the GZIP format.

For an extended overview, see Gzip Class Overview.

Object Creation

obj = Chilkat::CkGzip.new()

Properties

AbortCurrent
# boolVal is a boolean
boolVal = gzip.get_AbortCurrent();
gzip.put_AbortCurrent(boolVal);
Introduced in version 9.5.0.58

Set this property to true to request that the currently running operation be aborted. This is useful for long-running operations such as large file compression or decompression. Methods that complete quickly are generally not affected.

If no method is currently running, the property is automatically reset to false when the next method begins. After an abort occurs, it is also reset to false. Both synchronous and asynchronous operations can be aborted. For synchronous calls, another thread must set this property.

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Comment
# strVal is a string
# ckStr is a CkString
gzip.get_Comment(ckStr);
strVal = gzip.comment();
gzip.put_Comment(strVal);

An optional comment to embed in the Gzip file when a Compress* method is called.

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CompressionLevel
# intVal is an integer
intVal = gzip.get_CompressionLevel();
gzip.put_CompressionLevel(intVal);
Introduced in version 9.5.0.50

Controls the compression level used when creating Gzip data. The value can range from 0 to 9.

  • 0 = no compression
  • 9 = maximum compression

The default value is 6, which is a typical balance between compression size and speed. Higher levels may take significantly more CPU time while producing only slightly smaller output, depending on the data.

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DebugLogFilePath
# strVal is a string
# ckStr is a CkString
gzip.get_DebugLogFilePath(ckStr);
strVal = gzip.debugLogFilePath();
gzip.put_DebugLogFilePath(strVal);

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.

More Information and Examples
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Filename
# strVal is a string
# ckStr is a CkString
gzip.get_Filename(ckStr);
strVal = gzip.filename();
gzip.put_Filename(strVal);

The filename to embed in the Gzip file when a Compress* method is called. Some Gzip extraction tools use this embedded filename as the default output filename.

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LastErrorHtml
# strVal is a string
# ckStr is a CkString
gzip.get_LastErrorHtml(ckStr);
strVal = gzip.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
# strVal is a string
# ckStr is a CkString
gzip.get_LastErrorText(ckStr);
strVal = gzip.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
# strVal is a string
# ckStr is a CkString
gzip.get_LastErrorXml(ckStr);
strVal = gzip.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
# boolVal is a boolean
boolVal = gzip.get_LastMethodSuccess();
gzip.put_LastMethodSuccess(boolVal);

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. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.

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LastModStr
# strVal is a string
# ckStr is a CkString
gzip.get_LastModStr(ckStr);
strVal = gzip.lastModStr();
gzip.put_LastModStr(strVal);

Specifies the last-modified date/time to embed in the Gzip file when a Compress* method is called.

The value must be provided as an RFC 822 formatted date/time string.

Example:

Tue, 15 Nov 1994 12:45:26 GMT

If this property is not set, the current system date/time is used automatically.

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UseCurrentDate
# boolVal is a boolean
boolVal = gzip.get_UseCurrentDate();
gzip.put_UseCurrentDate(boolVal);

Controls the last-modified date/time assigned to files created by Uncompress* methods.

When set to true, the extracted file uses the current date/time instead of the date/time stored in the Gzip data.

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Utf8
# boolVal is a boolean
boolVal = gzip.get_Utf8();
gzip.put_Utf8(boolVal);

When set to true, all string 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.

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VerboseLogging
# boolVal is a boolean
boolVal = gzip.get_VerboseLogging();
gzip.put_VerboseLogging(boolVal);

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.

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Version
# strVal is a string
# ckStr is a CkString
gzip.get_Version(ckStr);
strVal = gzip.version();

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

More Information and Examples
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Methods

CompressBd
# binDat is a CkBinData
status = gzip.CompressBd(binDat);
Introduced in version 9.5.0.67

Compresses the contents of a BinData object in place, replacing the original data with Gzip-compressed data.

Returns true for success, false for failure.

More Information and Examples
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CompressBdAsync (1)
# returns a CkTask
# binDat is a CkBinData
ret_task = gzip.CompressBdAsync(binDat);
Introduced in version 9.5.0.67

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

Returns nil on failure

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CompressFile
# srcPath is a string
# destPath is a string
status = gzip.CompressFile(srcPath, destPath);

Compresses a file and writes the result as a Gzip file, typically with a .gz extension.

Returns true for success, false for failure.

More Information and Examples
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CompressFileAsync (1)
# returns a CkTask
# srcPath is a string
# destPath is a string
ret_task = gzip.CompressFileAsync(srcPath, destPath);

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

Returns nil on failure

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CompressFile2
# srcPath is a string
# embeddedFilename is a string
# destPath is a string
status = gzip.CompressFile2(srcPath, embeddedFilename, destPath);

Compresses a file and writes the result as a Gzip file, while allowing a different filename to be embedded inside the Gzip data.

The inFilename parameter is the actual file on disk. The srcPath parameter is the filename stored in the Gzip header and may be used by extraction tools as the output filename.

Returns true for success, false for failure.

More Information and Examples
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CompressFile2Async (1)
# returns a CkTask
# srcPath is a string
# embeddedFilename is a string
# destPath is a string
ret_task = gzip.CompressFile2Async(srcPath, embeddedFilename, destPath);

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

Returns nil on failure

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CompressFileBd
# filePath is a string
# bd is a CkBinData
status = gzip.CompressFileBd(filePath, bd);
Introduced in version 11.0.0

Compresses a file and stores the resulting Gzip data in a BinData object.

The compressed output is held in memory. The maximum compressed size is 4 GB.

Returns true for success, false for failure.

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CompressFileBdAsync (1)
# returns a CkTask
# filePath is a string
# bd is a CkBinData
ret_task = gzip.CompressFileBdAsync(filePath, bd);
Introduced in version 11.0.0

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

Returns nil on failure

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CompressSb
# sb is a CkStringBuilder
# charset is a string
# bd is a CkBinData
status = gzip.CompressSb(sb, charset, bd);
Introduced in version 11.0.0

Compresses the text contained in a StringBuilder and writes the Gzip-compressed result to a BinData object.

Before compression, the string is converted to bytes using the specified character set, such as utf-8, iso-8859-1, or shift_JIS.

Returns true for success, false for failure.

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CompressSbAsync (1)
# returns a CkTask
# sb is a CkStringBuilder
# charset is a string
# bd is a CkBinData
ret_task = gzip.CompressSbAsync(sb, charset, bd);
Introduced in version 11.0.0

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

Returns nil on failure

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CompressStringENC
# inStr is a string
# charset is a string
# encoding is a string
# outStr is a CkString (output)
status = gzip.CompressStringENC(inStr, charset, encoding, outStr);
retStr = gzip.compressStringENC(inStr, charset, encoding);

Compresses a string and returns the Gzip-compressed data as an encoded string.

The input string is first converted to bytes using the specified character set. The compressed binary data is then encoded using the requested encoding, such as base64, hex, url, base32, or quoted-printable.

Returns true for success, false for failure.

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CompressStringToFile
# inStr is a string
# destCharset is a string
# destPath is a string
status = gzip.CompressStringToFile(inStr, destCharset, destPath);

Compresses a string and writes the resulting Gzip data to a file.

The string is first converted to bytes using the character set specified by destCharset.

Returns true for success, false for failure.

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CompressStringToFileAsync (1)
# returns a CkTask
# inStr is a string
# destCharset is a string
# destPath is a string
ret_task = gzip.CompressStringToFileAsync(inStr, destCharset, destPath);

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

Returns nil on failure

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ExamineFile
# filePath is a string
retBool = gzip.ExamineFile(filePath);

Checks whether the specified file contains Gzip-formatted data.

Returns true if the file is in Gzip format, or false otherwise.

More Information and Examples
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IsGzip
# bd is a CkBinData
retBool = gzip.IsGzip(bd);
Introduced in version 11.0.0

Checks whether the data contained in a BinData object is in Gzip format.

Returns true if the data is Gzip-formatted, or false otherwise.

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LoadTaskCaller
# task is a CkTask
status = gzip.LoadTaskCaller(task);
Introduced in version 9.5.0.80

Loads the caller of the task's async method.

Returns true for success, false for failure.

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SetDt
# dt is a CkDateTime
status = gzip.SetDt(dt);

Sets the last-modified date/time to embed in the Gzip file when a Compress* method is called.

If no date/time is explicitly set, the current system date/time is used.

Returns true for success, false for failure.

More Information and Examples
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SetExtraData
# encodedData is a string
# encoding is a string
status = gzip.SetExtraData(encodedData, encoding);
Introduced in version 11.0.0

Sets optional extra binary data to include in the Gzip header when a Compress* method is called.

The data is passed as an encoded string. Supported encodings include base64, hex, ascii, and many others.

Returns true for success, false for failure.

More Information and Examples
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UncompressBd
# binDat is a CkBinData
status = gzip.UncompressBd(binDat);
Introduced in version 9.5.0.67

Decompresses Gzip data contained in a BinData object in place, replacing the compressed data with the uncompressed data.

Returns true for success, false for failure.

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UncompressBdAsync (1)
# returns a CkTask
# binDat is a CkBinData
ret_task = gzip.UncompressBdAsync(binDat);
Introduced in version 9.5.0.67

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

Returns nil on failure

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UncompressBdToFile
# bd is a CkBinData
# filePath is a string
status = gzip.UncompressBdToFile(bd, filePath);
Introduced in version 11.0.0

Decompresses Gzip data stored in a BinData object and writes the result to a file.

Returns true for success, false for failure.

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UncompressBdToFileAsync (1)
# returns a CkTask
# bd is a CkBinData
# filePath is a string
ret_task = gzip.UncompressBdToFileAsync(bd, filePath);
Introduced in version 11.0.0

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

Returns nil on failure

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UncompressFile
# srcPath is a string
# destPath is a string
status = gzip.UncompressFile(srcPath, destPath);

Decompresses a Gzip file and writes the result to the specified output path.

The output filename is provided by the caller. The filename embedded in the Gzip data is not used.

Returns true for success, false for failure.

More Information and Examples
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UncompressFileAsync (1)
# returns a CkTask
# srcPath is a string
# destPath is a string
ret_task = gzip.UncompressFileAsync(srcPath, destPath);

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

Returns nil on failure

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UncompressFileToString
# srcPath is a string
# charset is a string
# outStr is a CkString (output)
status = gzip.UncompressFileToString(srcPath, charset, outStr);
retStr = gzip.uncompressFileToString(srcPath, charset);

Decompresses a Gzip file that contains text and returns the uncompressed text as a string.

The charset parameter specifies the character encoding of the uncompressed text, such as utf-8, iso-8859-1, windows-1252, shift_JIS, big5, etc.

Returns true for success, false for failure.

More Information and Examples
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UncompressFileToStringAsync (1)
# returns a CkTask
# srcPath is a string
# charset is a string
ret_task = gzip.UncompressFileToStringAsync(srcPath, charset);

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

Returns nil on failure

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UncompressStringENC
# inStr is a string
# charset is a string
# encoding is a string
# outStr is a CkString (output)
status = gzip.UncompressStringENC(inStr, charset, encoding, outStr);
retStr = gzip.uncompressStringENC(inStr, charset, encoding);

Decompresses Gzip data provided as an encoded string and returns the uncompressed result as text.

The input string is first decoded using the specified encoding, such as base64, hex, url, base32, quoted-printable, etc. The decoded Gzip data is then decompressed and converted to text using the specified character set.

Returns true for success, false for failure.

More Information and Examples
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UnTarGz
# gzPath is a string
# destDir is a string
# bNoAbsolute is a boolean
status = gzip.UnTarGz(gzPath, destDir, bNoAbsolute);

Extracts a .tar.gz archive to a directory.

The Gzip decompression and TAR extraction are performed in streaming mode. No temporary files are created, and memory usage remains small and constant.

If bNoAbsolute is true, absolute paths in the TAR archive are not allowed. This helps protect against extracting files to unsafe locations, such as system directories.

Returns true for success, false for failure.

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UnTarGzAsync (1)
# returns a CkTask
# gzPath is a string
# destDir is a string
# bNoAbsolute is a boolean
ret_task = gzip.UnTarGzAsync(gzPath, destDir, bNoAbsolute);

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

Returns nil on failure

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XfdlToXml
# xfldData is a string
# outStr is a CkString (output)
status = gzip.XfdlToXml(xfldData, outStr);
retStr = gzip.xfdlToXml(xfldData);

Converts base64-encoded, Gzip-compressed XFDL data to XML text.

The input contains base64 data. The method decodes it, decompresses the Gzip data, and returns the resulting XML string.

XFDL (Extensible Forms Description Language) is an XML-based format used to define secure, interactive electronic forms—often including digital signatures and integrity protections—commonly used in government and enterprise applications.

Returns true for success, false for failure.

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Deprecated

CompressFileToMem Deprecated
# inFilename is a string
# outData is a CkByteData (output)
status = gzip.CompressFileToMem(inFilename, outData);

Compresses a file and returns the resulting Gzip data as a byte array.

The compressed output is held in memory and has a maximum size limit of 4 GB.

Returns true for success, false for failure.

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CompressFileToMemAsync Deprecated (1)
# returns a CkTask
# inFilename is a string
ret_task = gzip.CompressFileToMemAsync(inFilename);

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

Returns nil on failure

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CompressMemory Deprecated
# inData is a CkByteData
# outData is a CkByteData (output)
status = gzip.CompressMemory(inData, outData);

Compresses a byte array and returns the result as an in-memory Gzip image.

The uncompressed input data must not exceed 4 GB.

Returns true for success, false for failure.

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CompressMemoryAsync Deprecated (1)
# returns a CkTask
# inData is a CkByteData
ret_task = gzip.CompressMemoryAsync(inData);

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

Returns nil on failure

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CompressMemToFile Deprecated
# inData is a CkByteData
# destPath is a string
status = gzip.CompressMemToFile(inData, destPath);

Compresses a byte array and writes the resulting Gzip data to a file.

Returns true for success, false for failure.

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CompressMemToFileAsync Deprecated (1)
# returns a CkTask
# inData is a CkByteData
# destPath is a string
ret_task = gzip.CompressMemToFileAsync(inData, destPath);

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

Returns nil on failure

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CompressString Deprecated
# inStr is a string
# destCharset is a string
# outBytes is a CkByteData (output)
status = gzip.CompressString(inStr, destCharset, outData);

Compresses a string and returns the Gzip-compressed data as a byte array.

The string is first converted to bytes using the character set specified by destCharset. Common values include utf-8, iso-8859-1, and shift_JIS.

Returns true for success, false for failure.

More Information and Examples
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CompressStringAsync Deprecated (1)
# returns a CkTask
# inStr is a string
# destCharset is a string
ret_task = gzip.CompressStringAsync(inStr, destCharset);

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

Returns nil on failure

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Decode Deprecated
# encodedStr is a string
# encoding is a string
# outBytes is a CkByteData (output)
status = gzip.Decode(encodedStr, encoding, outData);
This method is 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.

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DeflateStringENC
# inString is a string
# charsetName is a string
# outputEncoding is a string
# outStr is a CkString (output)
status = gzip.DeflateStringENC(inString, charsetName, outputEncoding, outStr);
retStr = gzip.deflateStringENC(inString, charsetName, outputEncoding);
This method is deprecated.

Compresses a string using the raw deflate algorithm and returns the compressed data as an encoded string.

The input string is first converted to bytes using the specified character set. The compressed binary data is then encoded using the requested output encoding, such as hex, base64, url, or quoted-printable.

Important: This method produces raw deflate-compressed data, not Gzip-format data. Use the Compress* methods when Gzip format output is required.

Returns true for success, false for failure.

More Information and Examples
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Encode Deprecated
# byteData is a CkByteData
# encoding is a string
# outStr is a CkString (output)
status = gzip.Encode(byteData, encoding, outStr);
retStr = gzip.encode(byteData, encoding);
This method is deprecated.

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.

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ExamineMemory Deprecated
# inGzData is a CkByteData
retBool = gzip.ExamineMemory(inGzData);

Checks whether the provided byte array contains Gzip-formatted data.

Returns true if the data is in Gzip format, or false otherwise.

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GetDt
# returns a CkDateTime
ret_ckDateTime = gzip.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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InflateStringENC
# inString is a string
# convertFromCharset is a string
# inputEncoding is a string
# outStr is a CkString (output)
status = gzip.InflateStringENC(inString, convertFromCharset, inputEncoding, outStr);
retStr = gzip.inflateStringENC(inString, convertFromCharset, inputEncoding);
This method is deprecated.

Decompresses data previously compressed with DeflateStringENC.

The input string is first decoded using the specified input encoding, such as hex, base64, url, or quoted-printable. The resulting compressed bytes are then inflated, and the final bytes are converted to a string using the specified character set.

Returns true for success, false for failure.

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ReadFile Deprecated
# path is a string
# outBytes is a CkByteData (output)
status = gzip.ReadFile(path, outData);
This method is 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.

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UncompressFileToMem Deprecated
# srcPath is a string
# outData is a CkByteData (output)
status = gzip.UncompressFileToMem(srcPath, outData);

Decompresses a Gzip file and returns the uncompressed data as a byte array.

The uncompressed output is held in memory and must not exceed 4 GB.

Returns true for success, false for failure.

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UncompressFileToMemAsync Deprecated (1)
# returns a CkTask
# srcPath is a string
ret_task = gzip.UncompressFileToMemAsync(srcPath);

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

Returns nil on failure

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UncompressMemory Deprecated
# inData is a CkByteData
# outData is a CkByteData (output)
status = gzip.UncompressMemory(inData, outData);

Decompresses an in-memory Gzip image and returns the uncompressed data as a byte array.

The uncompressed output is held in memory and must not exceed 4 GB.

Returns true for success, false for failure.

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UncompressMemoryAsync Deprecated (1)
# returns a CkTask
# inData is a CkByteData
ret_task = gzip.UncompressMemoryAsync(inData);

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

Returns nil on failure

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UncompressMemToFile Deprecated
# inData is a CkByteData
# destPath is a string
status = gzip.UncompressMemToFile(inData, destPath);

Decompresses an in-memory Gzip image and writes the uncompressed data to a file.

Returns true for success, false for failure.

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UncompressMemToFileAsync Deprecated (1)
# returns a CkTask
# inData is a CkByteData
# destPath is a string
ret_task = gzip.UncompressMemToFileAsync(inData, destPath);

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

Returns nil on failure

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UncompressString Deprecated
# inData is a CkByteData
# inCharset is a string
# outStr is a CkString (output)
status = gzip.UncompressString(inData, inCharset, outStr);
retStr = gzip.uncompressString(inData, inCharset);

Decompresses Gzip-compressed data and returns the result as a string.

After decompression, the result is raw binary data (a sequence of bytes). These bytes are then interpreted as text using the specified character set (such as utf-8, iso-8859-1, etc.) to produce the final string.

Internally, Chilkat converts the byte sequence to a string by interpreting the bytes according to the specified character set. For example, if utf-8 is specified, the bytes are treated as the UTF-8 byte representation of text and decoded into the internal string format used by the programming language.

It is important that the character set matches the one originally used when the data was compressed. If the wrong character set is used, the byte-to-text conversion may produce incorrect or unreadable characters.

Returns true for success, false for failure.

More Information and Examples
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UncompressStringAsync Deprecated (1)
# returns a CkTask
# inData is a CkByteData
# inCharset is a string
ret_task = gzip.UncompressStringAsync(inData, inCharset);

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

Returns nil on failure

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WriteFile Deprecated
# path is a string
# binaryData is a CkByteData
status = gzip.WriteFile(path, binaryData);
This method is deprecated.

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

Returns true for success, false for failure.

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