---
product: Chilkat
product_version: 11.7.0
language: csharp
language_label: C#
class: Gzip
license: bundle
deprecated: false
reference_html: https://www.chilkatsoft.com/refdoc/csGzipRef.html
---
# Chilkat Gzip — C# — v11.7.0

> Chilkat 11.7.0 · language=csharp · class=Gzip
> Other versions: replace `11.7.0` in this URL. Other languages: `https://www.chilkatsoft.com/ai-docs/v/11.7.0/<lang>/classes/Gzip.md`.
> Language-wide rules (install, unlock, error model, strings/bytes): `https://www.chilkatsoft.com/ai-docs/v/11.7.0/csharp/guide.md`.

## Purpose

**Compress, decompress, inspect, and convert GZIP data in files or memory.**

`Chilkat.Gzip` provides GZIP compression and decompression for file-based and in-memory workflows. It can compress and uncompress files, strings, byte arrays, `BinData`, and encoded data such as Base64 or hex. It also supports `.tar.gz` extraction, gzip metadata such as original filename, timestamp, and comments, and inspection of GZIP header information without fully expanding the compressed data.

**File compression**

Compress files to `.gz`, uncompress `.gz` files, and write decompressed output directly to disk.

**Memory-based data**

Work with byte arrays and `Chilkat.BinData` for applications that need compression or decompression without temporary files.

**String workflows**

Compress and uncompress strings with explicit charset handling for text data that must round-trip correctly.

**Encoded GZIP data**

Handle GZIP data represented as Base64, hex, or other supported encoded forms when binary data must be carried as text.

**GZIP metadata**

Set or inspect metadata such as original filename, modified time, comments, and extra data stored in the GZIP header.

**Tar-gzip and XFDL**

Extract `.tar.gz` archives and decode XFDL content that uses gzip-related encodings.

**Common pattern:** Use `Gzip` when the data is a single GZIP stream, a `.gz` file, or a `.tar.gz` archive. For ZIP archives, use `Chilkat.Zip`; for raw deflate or zlib-style compression, use `Chilkat.Compression`.

For an extended overview, see [Gzip Class Overview](https://www.chilkatsoft.com/gzip_overview.asp).

## Object creation, unlocking and error handling

**Object Creation**

```csharp
Chilkat.Gzip obj = new Chilkat.Gzip();
```

Call `Global.UnlockBundle` once at the start of the program, before using this or any other Chilkat class. Any string unlocks a fully functional 30-day trial; a purchased unlock code is used in production. See `guide.md` for the exact code in C#.

Minimal complete program:

```csharp
// Required once per process. Any string unlocks a 30-day trial; use your purchased code in production.
Chilkat.Global glob = new Chilkat.Global();
if (!glob.UnlockBundle("Anything for 30-day trial"))
{
    Console.WriteLine(glob.LastErrorText);
    return;
}

Chilkat.Gzip gzip = new Chilkat.Gzip();

bool success = gzip.CompressFile("<srcPath>", "<destPath>");
if (!success)
{
    Console.WriteLine(gzip.LastErrorText);   // full diagnostic of what went wrong
    return;
}
```

How failure is reported depends on the method's return type and is stated in the note under each method below. In every case the diagnostic text is in the `LastErrorText` property of the object whose method was called.

## Members common to every Chilkat class

Documented once per language in `common-members.md`; listed here so this page is self-contained.

| Property | Signature | Access | Meaning |
|---|---|---|---|
| `DebugLogFilePath` | `public string DebugLogFilePath {get; set; }` | read/write | If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. |
| `LastErrorHtml` | `public string LastErrorHtml {get; }` | read-only | Provides HTML-formatted information about the last called method or property. |
| `LastErrorText` | `public string LastErrorText {get; }` | read-only | Provides plain text information about the last called method or property. |
| `LastErrorXml` | `public string LastErrorXml {get; }` | read-only | Provides XML-formatted information about the last called method or property. |
| `LastMethodSuccess` | `public bool LastMethodSuccess {get; set; }` | read/write | Indicates the success or failure of the most recent method call: `true` means success, `false` means failure. |
| `VerboseLogging` | `public bool VerboseLogging {get; set; }` | read/write | If set to `true`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. |
| `Version` | `public string Version {get; }` | read-only | Version of the component/library, such as "10.1.0" |

## Member index

| Member | Kind | Signature |
|---|---|---|
| `AbortCurrent` | property, read/write | `public bool AbortCurrent {get; set; }` |
| `Comment` | property, read/write | `public string Comment {get; set; }` |
| `CompressionLevel` | property, read/write | `public int CompressionLevel {get; set; }` |
| `ExtraData` | property, read/write | `public byte[] ExtraData {get; set; }` |
| `Filename` | property, read/write | `public string Filename {get; set; }` |
| `HeartbeatMs` | property, read/write | `public int HeartbeatMs {get; set; }` |
| `LastModStr` | property, read/write | `public string LastModStr {get; set; }` |
| `UseCurrentDate` | property, read/write | `public bool UseCurrentDate {get; set; }` |
| `CompressBd` | method | `public bool CompressBd(BinData binDat);` |
| `CompressFile` | method | `public bool CompressFile(string srcPath, string destPath);` |
| `CompressFile2` | method | `public bool CompressFile2(string srcPath, string embeddedFilename, string destPath);` |
| `CompressFileBd` | method | `public bool CompressFileBd(string filePath, BinData bd);` |
| `CompressFileToMem` | method | `public byte[] CompressFileToMem(string inFilename);` |
| `CompressMemory` | method | `public byte[] CompressMemory(byte[] inData);` |
| `CompressMemToFile` | method | `public bool CompressMemToFile(byte[] inData, string destPath);` |
| `CompressSb` | method | `public bool CompressSb(StringBuilder sb, string charset, BinData bd);` |
| `CompressString` | method | `public byte[] CompressString(string inStr, string destCharset);` |
| `CompressStringENC` | method | `public string CompressStringENC(string inStr, string charset, string encoding);` |
| `CompressStringToFile` | method | `public bool CompressStringToFile(string inStr, string destCharset, string destPath);` |
| `GetGzipInfo` | method | `public bool GetGzipInfo(string filePath, JsonObject json);` |
| `GetGzipInfoBd` | method | `public bool GetGzipInfoBd(BinData bd, JsonObject json);` |
| `IsGzip` | method | `public bool IsGzip(BinData bd);` |
| `LoadTaskCaller` | method | `public bool LoadTaskCaller(Task task);` |
| `SetDt` | method | `public bool SetDt(CkDateTime dt);` |
| `SetExtraData` | method | `public bool SetExtraData(string encodedData, string encoding);` |
| `UncompressBd` | method | `public bool UncompressBd(BinData binDat);` |
| `UncompressBdToFile` | method | `public bool UncompressBdToFile(BinData bd, string filePath);` |
| `UncompressFile` | method | `public bool UncompressFile(string srcPath, string destPath);` |
| `UncompressFileToMem` | method | `public byte[] UncompressFileToMem(string srcPath);` |
| `UncompressFileToString` | method | `public string UncompressFileToString(string srcPath, string charset);` |
| `UncompressMemory` | method | `public byte[] UncompressMemory(byte[] inData);` |
| `UncompressMemToFile` | method | `public bool UncompressMemToFile(byte[] inData, string destPath);` |
| `UncompressString` | method | `public string UncompressString(byte[] inData, string inCharset);` |
| `UncompressStringENC` | method | `public string UncompressStringENC(string inStr, string charset, string encoding);` |
| `UnTarGz` | method | `public bool UnTarGz(string gzPath, string destDir, bool bNoAbsolute);` |
| `XfdlToXml` | method | `public string XfdlToXml(string xfldData);` |

Deprecated members are listed at the end of this file with their replacements; do not use them in new code.

## Properties

### Gzip.AbortCurrent

`Chilkat 11.7.0 · csharp · Gzip · AbortCurrent · property · read/write · since 9.5.0.58`

```csharp
public bool AbortCurrent {get; set; }
```

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.

### Gzip.Comment

`Chilkat 11.7.0 · csharp · Gzip · Comment · property · read/write`

```csharp
public string Comment {get; set; }
```

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

### Gzip.CompressionLevel

`Chilkat 11.7.0 · csharp · Gzip · CompressionLevel · property · read/write · since 9.5.0.50`

```csharp
public int CompressionLevel {get; set; }
```

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.

### Gzip.ExtraData

`Chilkat 11.7.0 · csharp · Gzip · ExtraData · property · read/write`

```csharp
public byte[] ExtraData {get; set; }
```

Optional binary data to include in the Gzip header when a `Compress*` method is called.

### Gzip.Filename

`Chilkat 11.7.0 · csharp · Gzip · Filename · property · read/write`

```csharp
public string Filename {get; set; }
```

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.

### Gzip.HeartbeatMs

`Chilkat 11.7.0 · csharp · Gzip · HeartbeatMs · property · read/write`

```csharp
public int HeartbeatMs {get; set; }
```

**Full documentation for this property (same in every language):** [Event Callback Examples](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/event_callback_examples.md)

Specifies the interval, in milliseconds, between `AbortCheck` event callbacks. These callbacks allow an application to cancel certain long-running operations before they finish.

The default value is `0`, which means no `AbortCheck` callbacks are triggered.

### Gzip.LastModStr

`Chilkat 11.7.0 · csharp · Gzip · LastModStr · property · read/write`

```csharp
public string LastModStr {get; set; }
```

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:**

```
Sun, 12 Apr 2026 12:45:26 GMT
```

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

### Gzip.UseCurrentDate

`Chilkat 11.7.0 · csharp · Gzip · UseCurrentDate · property · read/write`

```csharp
public bool UseCurrentDate {get; set; }
```

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.

## Methods

### Gzip.CompressBd

`Chilkat 11.7.0 · csharp · Gzip · CompressBd · method · since 9.5.0.67`

```csharp
public bool CompressBd(BinData binDat);
```

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

Returns true for success, false for failure.

Async variant: `CompressBdAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.CompressFile

`Chilkat 11.7.0 · csharp · Gzip · CompressFile · method`

```csharp
public bool CompressFile(string srcPath, string destPath);
```

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

Returns true for success, false for failure.

Async variant: `CompressFileAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.CompressFile2

`Chilkat 11.7.0 · csharp · Gzip · CompressFile2 · method`

```csharp
public bool CompressFile2(string srcPath, string embeddedFilename, string 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.

Async variant: `CompressFile2Async` — same arguments, returns a `Task` (see Async variants below).

### Gzip.CompressFileBd

`Chilkat 11.7.0 · csharp · Gzip · CompressFileBd · method · since 11.0.0`

```csharp
public bool CompressFileBd(string filePath, BinData bd);
```

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.

Async variant: `CompressFileBdAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.CompressFileToMem

`Chilkat 11.7.0 · csharp · Gzip · CompressFileToMem · method`

```csharp
public byte[] CompressFileToMem(string inFilename);
```

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 an empty byte array on failure

Async variant: `CompressFileToMemAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.CompressMemory

`Chilkat 11.7.0 · csharp · Gzip · CompressMemory · method`

```csharp
public byte[] CompressMemory(byte[] inData);
```

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

The uncompressed input data must not exceed 4 GB.

Returns an empty byte array on failure

Async variant: `CompressMemoryAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.CompressMemToFile

`Chilkat 11.7.0 · csharp · Gzip · CompressMemToFile · method`

```csharp
public bool CompressMemToFile(byte[] inData, string destPath);
```

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

Returns true for success, false for failure.

Async variant: `CompressMemToFileAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.CompressSb

`Chilkat 11.7.0 · csharp · Gzip · CompressSb · method · since 11.0.0`

```csharp
public bool CompressSb(StringBuilder sb, string charset, BinData bd);
```

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.

Async variant: `CompressSbAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.CompressString

`Chilkat 11.7.0 · csharp · Gzip · CompressString · method`

```csharp
public byte[] CompressString(string inStr, string destCharset);
```

**Full documentation for this method (same in every language):** [Full List of Charset Names](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/charsets_supported_by_chilkat.md)

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 an empty byte array on failure

Async variant: `CompressStringAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.CompressStringENC

`Chilkat 11.7.0 · csharp · Gzip · CompressStringENC · method`

```csharp
public string CompressStringENC(string inStr, string charset, string encoding);
```

**Full documentation for this method (same in every language):** [Binary Encodings Supported by Chilkat](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/binary_encodings.md)

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 `null` on failure

### Gzip.CompressStringToFile

`Chilkat 11.7.0 · csharp · Gzip · CompressStringToFile · method`

```csharp
public bool CompressStringToFile(string inStr, string destCharset, string destPath);
```

**Full documentation for this method (same in every language):** [Full List of Charset Names](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/charsets_supported_by_chilkat.md)

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.

Async variant: `CompressStringToFileAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.GetGzipInfo

`Chilkat 11.7.0 · csharp · Gzip · GetGzipInfo · method · since 11.5.0`

```csharp
public bool GetGzipInfo(string filePath, JsonObject json);
```

Retrieves metadata stored in a Gzip file and returns the information in a `JsonObject`.

The metadata is returned using the following JSON structure:

```
{
  "extraData": "AAECAw==",
  "filename": "example.txt",
  "comment": "This is the comment"
}
```

- **filename** – the original filename embedded in the Gzip file (if present)
- **comment** – an optional descriptive comment (if present)
- **extraData** – optional additional binary data, returned as a Base64-encoded string

Any of these fields may be omitted if they were not included when the Gzip file was created.

Returns true for success, false for failure.

### Gzip.GetGzipInfoBd

`Chilkat 11.7.0 · csharp · Gzip · GetGzipInfoBd · method · since 11.5.0`

```csharp
public bool GetGzipInfoBd(BinData bd, JsonObject json);
```

Retrieves metadata stored in Gzip data contained within a `BinData` object and returns the information in a `JsonObject`.

The metadata is returned using the same JSON structure:

```
{
  "extraData": "AAECAw==",
  "filename": "example.txt",
  "comment": "This is the comment"
}
```

- **filename** – the original filename embedded in the Gzip data (if present)
- **comment** – an optional descriptive comment (if present)
- **extraData** – optional additional binary data, returned as a Base64-encoded string

Any of these fields may be omitted if they were not included when the Gzip data was created.

Returns true for success, false for failure.

### Gzip.IsGzip

`Chilkat 11.7.0 · csharp · Gzip · IsGzip · method · since 11.0.0`

```csharp
public bool IsGzip(BinData bd);
```

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

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

### Gzip.LoadTaskCaller

`Chilkat 11.7.0 · csharp · Gzip · LoadTaskCaller · method · since 9.5.0.80`

```csharp
public bool LoadTaskCaller(Task task);
```

Loads the caller of the task's async method.

Returns true for success, false for failure.

### Gzip.SetDt

`Chilkat 11.7.0 · csharp · Gzip · SetDt · method`

```csharp
public bool SetDt(CkDateTime 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.

### Gzip.SetExtraData

`Chilkat 11.7.0 · csharp · Gzip · SetExtraData · method · since 11.0.0`

```csharp
public bool SetExtraData(string encodedData, string encoding);
```

**Full documentation for this method (same in every language):** [Binary Encodings Supported by Chilkat](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/binary_encodings.md)

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.

### Gzip.UncompressBd

`Chilkat 11.7.0 · csharp · Gzip · UncompressBd · method · since 9.5.0.67`

```csharp
public bool UncompressBd(BinData binDat);
```

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.

Async variant: `UncompressBdAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.UncompressBdToFile

`Chilkat 11.7.0 · csharp · Gzip · UncompressBdToFile · method · since 11.0.0`

```csharp
public bool UncompressBdToFile(BinData bd, string filePath);
```

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

Returns true for success, false for failure.

Async variant: `UncompressBdToFileAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.UncompressFile

`Chilkat 11.7.0 · csharp · Gzip · UncompressFile · method`

```csharp
public bool UncompressFile(string srcPath, string 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.

Async variant: `UncompressFileAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.UncompressFileToMem

`Chilkat 11.7.0 · csharp · Gzip · UncompressFileToMem · method`

```csharp
public byte[] UncompressFileToMem(string srcPath);
```

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 an empty byte array on failure

Async variant: `UncompressFileToMemAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.UncompressFileToString

`Chilkat 11.7.0 · csharp · Gzip · UncompressFileToString · method`

```csharp
public string UncompressFileToString(string srcPath, string charset);
```

**Full documentation for this method (same in every language):** [List of Valid Charsets](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/charsets_supported_by_chilkat.md)

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 `null` on failure

Async variant: `UncompressFileToStringAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.UncompressMemory

`Chilkat 11.7.0 · csharp · Gzip · UncompressMemory · method`

```csharp
public byte[] UncompressMemory(byte[] inData);
```

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 an empty byte array on failure

Async variant: `UncompressMemoryAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.UncompressMemToFile

`Chilkat 11.7.0 · csharp · Gzip · UncompressMemToFile · method`

```csharp
public bool UncompressMemToFile(byte[] inData, string destPath);
```

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

Returns true for success, false for failure.

Async variant: `UncompressMemToFileAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.UncompressString

`Chilkat 11.7.0 · csharp · Gzip · UncompressString · method`

```csharp
public string UncompressString(byte[] inData, string inCharset);
```

**Full documentation for this method (same in every language):** [Full List of Charset Names](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/charsets_supported_by_chilkat.md)

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 `null` on failure

Async variant: `UncompressStringAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.UncompressStringENC

`Chilkat 11.7.0 · csharp · Gzip · UncompressStringENC · method`

```csharp
public string UncompressStringENC(string inStr, string charset, string encoding);
```

**Full documentation for this method (same in every language):** [Binary Encodings Supported by Chilkat](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/binary_encodings.md)

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 `null` on failure

### Gzip.UnTarGz

`Chilkat 11.7.0 · csharp · Gzip · UnTarGz · method`

```csharp
public bool UnTarGz(string gzPath, string destDir, bool 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.

Async variant: `UnTarGzAsync` — same arguments, returns a `Task` (see Async variants below).

### Gzip.XfdlToXml

`Chilkat 11.7.0 · csharp · Gzip · XfdlToXml · method`

```csharp
public string XfdlToXml(string xfldData);
```

**Full documentation for this method (same in every language):** [More about XFDL](https://www.chilkatsoft.com/ai-docs/v/11.7.0/articles/xfdl.md)

Converts encoded and compressed XFDL data to a decompressed XML string.

XFDL data is often stored in an ASCII-safe compressed form, such as `asci-gzip` or `asc-gzip`. Despite the name, this does not always mean the data is a standard `.gz` file. In some XFDL files, the compressed payload uses the raw deflate format rather than the full Gzip file format.

Chilkat automatically detects the actual encoding and compression format used by the XFDL data. It decodes the ASCII/Base64 representation, determines whether the compressed data is Gzip or deflate, decompresses it correctly, and returns the resulting XML string.

This allows applications to call `XfdlToXml` without needing to manually distinguish between XFDL variants such as Base64+Gzip and Base64+Deflate.

Returns the decoded and decompressed 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 `null` on failure

## Events and callbacks

### Gzip.AbortCheck (event)

`Chilkat 11.7.0 · csharp · Gzip · AbortCheck · event`

```csharp
public event AbortCheckEventHandler OnAbortCheck;
```

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.

### Chilkat .NET Framework Event Implementation

Args are passed using Chilkat.AbortCheckEventArgs

**Event callback implementation:**

```csharp
private void gzip_OnAbortCheck(object sender, Chilkat.AbortCheckEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Gzip gzip = new Chilkat.Gzip();
gzip.OnAbortCheck += gzip_OnAbortCheck;
```

### Chilkat .NET Core Event Implementation

**Event callback implementation:**

```csharp
public void handleAbortCheck(out bool abort)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Gzip gzip = new Chilkat.Gzip();
// ...
Chilkat.Gzip.AbortCheck abortCheck = new Chilkat.Gzip.AbortCheck(handleAbortCheck);
gzip.setAbortCheckCb(abortCheck);
```

### Gzip.PercentDone (event)

`Chilkat 11.7.0 · csharp · Gzip · PercentDone · event`

```csharp
public event PercentDoneEventHandler OnPercentDone;
```

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 `true`. This will cause the method to terminate and return a failure status or corresponding failure value.

### Chilkat .NET Framework Event Implementation

Args are passed using Chilkat.PercentDoneEventArgs

**Event callback implementation:**

```csharp
private void gzip_OnPercentDone(object sender, Chilkat.PercentDoneEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Gzip gzip = new Chilkat.Gzip();
gzip.OnPercentDone += gzip_OnPercentDone;
```

### Chilkat .NET Core Event Implementation

**Event callback implementation:**

```csharp
public void handlePercentDone(int pctDone, out bool abort)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Gzip gzip = new Chilkat.Gzip();
// ...
Chilkat.Gzip.PercentDone percentDone = new Chilkat.Gzip.PercentDone(handlePercentDone);
gzip.setPercentDoneCb(percentDone);
```

### Gzip.ProgressInfo (event)

`Chilkat 11.7.0 · csharp · Gzip · ProgressInfo · event`

```csharp
public event ProgressInfoEventHandler OnProgressInfo;
```

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.

Note: Some Chilkat methods don't fire any ProgressInfo events.

### Chilkat .NET Framework Event Implementation

Args are passed using Chilkat.ProgressInfoEventArgs

**Event callback implementation:**

```csharp
private void gzip_OnProgressInfo(object sender, Chilkat.ProgressInfoEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Gzip gzip = new Chilkat.Gzip();
gzip.OnProgressInfo += gzip_OnProgressInfo;
```

### Chilkat .NET Core Event Implementation

**Event callback implementation:**

```csharp
public void handleProgressInfo(string name, string value)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Gzip gzip = new Chilkat.Gzip();
// ...
Chilkat.Gzip.ProgressInfo progressInfo = new Chilkat.Gzip.ProgressInfo(handleProgressInfo);
gzip.setProgressInfoCb(progressInfo);
```

### Gzip.TaskCompleted (event)

`Chilkat 11.7.0 · csharp · Gzip · TaskCompleted · event`

```csharp
public event TaskCompletedEventHandler OnTaskCompleted;
```

Called from the background thread when an asynchronous task completes.

### Chilkat .NET Framework Event Implementation

Args are passed using Chilkat.TaskCompletedEventArgs

**Event callback implementation:**

```csharp
private void gzip_OnTaskCompleted(object sender, Chilkat.TaskCompletedEventArgs args)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Gzip gzip = new Chilkat.Gzip();
gzip.OnTaskCompleted += gzip_OnTaskCompleted;
```

### Chilkat .NET Core Event Implementation

**Event callback implementation:**

```csharp
public void handleTaskIdCompleted(int taskId)
	{
	    // application code goes here.
	}
```

**To add an event handler:**

```csharp
Chilkat.Gzip gzip = new Chilkat.Gzip();
// ...
Chilkat.Gzip.TaskIdCompleted taskIdCompleted = new Chilkat.Gzip.TaskIdCompleted(handleTaskIdCompleted);
gzip.setTaskIdCompletedCb(taskIdCompleted);
```

## Async variants

Each returns a `Task` instead of the result and takes the same arguments as the synchronous method; run the task, wait for `Finished`, then read the result from the task. No new Async methods are added from 11.7.0 on.

```csharp
public Task CompressBdAsync(BinData binDat);
public Task CompressFileAsync(string srcPath, string destPath);
public Task CompressFile2Async(string srcPath, string embeddedFilename, string destPath);
public Task CompressFileBdAsync(string filePath, BinData bd);
public Task CompressFileToMemAsync(string inFilename);
public Task CompressMemoryAsync(byte[] inData);
public Task CompressMemToFileAsync(byte[] inData, string destPath);
public Task CompressSbAsync(StringBuilder sb, string charset, BinData bd);
public Task CompressStringAsync(string inStr, string destCharset);
public Task CompressStringToFileAsync(string inStr, string destCharset, string destPath);
public Task UncompressBdAsync(BinData binDat);
public Task UncompressBdToFileAsync(BinData bd, string filePath);
public Task UncompressFileAsync(string srcPath, string destPath);
public Task UncompressFileToMemAsync(string srcPath);
public Task UncompressFileToStringAsync(string srcPath, string charset);
public Task UncompressMemoryAsync(byte[] inData);
public Task UncompressMemToFileAsync(byte[] inData, string destPath);
public Task UncompressStringAsync(byte[] inData, string inCharset);
public Task UnTarGzAsync(string gzPath, string destDir, bool bNoAbsolute);
```

## Deprecated members — do not use in new code

| Member | Kind | Deprecated in | Use instead |
|---|---|---|---|
| `Decode` | method | before 11.6.1 | — |
| `DeflateStringENC` | method | before 11.6.1 | — |
| `Encode` | method | before 11.6.1 | — |
| `ExamineFile` | method | before 11.6.1 | — |
| `ExamineMemory` | method | before 11.6.1 | — |
| `GetDt` | method | before 11.6.1 | — |
| `InflateStringENC` | method | before 11.6.1 | — |
| `ReadFile` | method | before 11.6.1 | — |
| `WriteFile` | method | before 11.6.1 | — |

## Related classes

[`BinData`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/csharp/classes/BinData.md), [`CkDateTime`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/csharp/classes/CkDateTime.md), [`JsonObject`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/csharp/classes/JsonObject.md), [`StringBuilder`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/csharp/classes/StringBuilder.md), [`Task`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/csharp/classes/Task.md)