---
product: Chilkat
product_version: 11.7.0
language: delphidll
language_label: Delphi DLL
class: Gzip
license: bundle
deprecated: false
reference_html: https://www.chilkatsoft.com/refdoc/dd_CkGzipRef.html
---
# Chilkat Gzip — Delphi DLL — v11.7.0

> Chilkat 11.7.0 · language=delphidll · 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/delphidll/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

**Create/Dispose**

```pascal
var
myObject: HCkGzip;

begin
myObject := CkGzip_Create();

// ...

CkGzip_Dispose(myObject);
end;
```

`function CkGzip_Create: HCkGzip; stdcall;`

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

`procedure CkGzip_Dispose(handle: HCkGzip); stdcall;`

Objects created by calling CkGzip_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function.

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 Delphi DLL.

## 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` | `procedure CkGzip_getDebugLogFilePath(objHandle: HCkGzip; outPropVal: HCkString); stdcall; procedure CkGzip_putDebugLogFilePath(objHandle: HCkGzip; newPropVal: PWideChar); stdcall; function CkGzip__debugLogFilePath(objHandle: HCkGzip): PWideChar; stdcall;` | 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` | `procedure CkGzip_getLastErrorHtml(objHandle: HCkGzip; outPropVal: HCkString); stdcall; function CkGzip__lastErrorHtml(objHandle: HCkGzip): PWideChar; stdcall;` | read-only | Provides HTML-formatted information about the last called method or property. |
| `LastErrorText` | `procedure CkGzip_getLastErrorText(objHandle: HCkGzip; outPropVal: HCkString); stdcall; function CkGzip__lastErrorText(objHandle: HCkGzip): PWideChar; stdcall;` | read-only | Provides plain text information about the last called method or property. |
| `LastErrorXml` | `procedure CkGzip_getLastErrorXml(objHandle: HCkGzip; outPropVal: HCkString); stdcall; function CkGzip__lastErrorXml(objHandle: HCkGzip): PWideChar; stdcall;` | read-only | Provides XML-formatted information about the last called method or property. |
| `LastMethodSuccess` | `function CkGzip_getLastMethodSuccess(objHandle: HCkGzip): wordbool; stdcall; procedure CkGzip_putLastMethodSuccess(objHandle: HCkGzip; newPropVal: wordbool); stdcall;` | read/write | Indicates the success or failure of the most recent method call: `True` means success, `False` means failure. |
| `VerboseLogging` | `function CkGzip_getVerboseLogging(objHandle: HCkGzip): wordbool; stdcall; procedure CkGzip_putVerboseLogging(objHandle: HCkGzip; newPropVal: wordbool); stdcall;` | read/write | If set to `True`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. |
| `Version` | `procedure CkGzip_getVersion(objHandle: HCkGzip; outPropVal: HCkString); stdcall; function CkGzip__version(objHandle: HCkGzip): PWideChar; stdcall;` | read-only | Version of the component/library, such as "10.1.0" |

## Member index

| Member | Kind | Signature |
|---|---|---|
| `AbortCurrent` | property, read/write | `function CkGzip_getAbortCurrent(objHandle: HCkGzip): wordbool; stdcall; procedure CkGzip_putAbortCurrent(objHandle: HCkGzip; newPropVal: wordbool); stdcall;` |
| `Comment` | property, read/write | `procedure CkGzip_getComment(objHandle: HCkGzip; outPropVal: HCkString); stdcall; procedure CkGzip_putComment(objHandle: HCkGzip; newPropVal: PWideChar); stdcall; function CkGzip__comment(objHandle: HCkGzip): PWideChar; stdcall;` |
| `CompressionLevel` | property, read/write | `function CkGzip_getCompressionLevel(objHandle: HCkGzip): Integer; stdcall; procedure CkGzip_putCompressionLevel(objHandle: HCkGzip; newPropVal: Integer); stdcall;` |
| `Filename` | property, read/write | `procedure CkGzip_getFilename(objHandle: HCkGzip; outPropVal: HCkString); stdcall; procedure CkGzip_putFilename(objHandle: HCkGzip; newPropVal: PWideChar); stdcall; function CkGzip__filename(objHandle: HCkGzip): PWideChar; stdcall;` |
| `HeartbeatMs` | property, read/write | `function CkGzip_getHeartbeatMs(objHandle: HCkGzip): Integer; stdcall; procedure CkGzip_putHeartbeatMs(objHandle: HCkGzip; newPropVal: Integer); stdcall;` |
| `LastModStr` | property, read/write | `procedure CkGzip_getLastModStr(objHandle: HCkGzip; outPropVal: HCkString); stdcall; procedure CkGzip_putLastModStr(objHandle: HCkGzip; newPropVal: PWideChar); stdcall; function CkGzip__lastModStr(objHandle: HCkGzip): PWideChar; stdcall;` |
| `UseCurrentDate` | property, read/write | `function CkGzip_getUseCurrentDate(objHandle: HCkGzip): wordbool; stdcall; procedure CkGzip_putUseCurrentDate(objHandle: HCkGzip; newPropVal: wordbool); stdcall;` |
| `CompressBd` | method | `function CkGzip_CompressBd(objHandle: HCkGzip;     binDat: HCkBinData): wordbool; stdcall;` |
| `CompressFile` | method | `function CkGzip_CompressFile(objHandle: HCkGzip;     srcPath: PWideChar;     destPath: PWideChar): wordbool; stdcall;` |
| `CompressFile2` | method | `function CkGzip_CompressFile2(objHandle: HCkGzip;     srcPath: PWideChar;     embeddedFilename: PWideChar;     destPath: PWideChar): wordbool; stdcall;` |
| `CompressFileBd` | method | `function CkGzip_CompressFileBd(objHandle: HCkGzip;     filePath: PWideChar;     bd: HCkBinData): wordbool; stdcall;` |
| `CompressSb` | method | `function CkGzip_CompressSb(objHandle: HCkGzip;     sb: HCkStringBuilder;     charset: PWideChar;     bd: HCkBinData): wordbool; stdcall;` |
| `CompressStringENC` | method | `function CkGzip_CompressStringENC(objHandle: HCkGzip;     inStr: PWideChar;     charset: PWideChar;     encoding: PWideChar;     outStr: HCkString): wordbool; stdcall; function CkGzip__compressStringENC(objHandle: HCkGzip;     inStr: PWideChar;     charset: PWideChar;     encoding: PWideChar): PWideChar; stdcall;` |
| `CompressStringToFile` | method | `function CkGzip_CompressStringToFile(objHandle: HCkGzip;     inStr: PWideChar;     destCharset: PWideChar;     destPath: PWideChar): wordbool; stdcall;` |
| `GetGzipInfo` | method | `function CkGzip_GetGzipInfo(objHandle: HCkGzip;     filePath: PWideChar;     json: HCkJsonObject): wordbool; stdcall;` |
| `GetGzipInfoBd` | method | `function CkGzip_GetGzipInfoBd(objHandle: HCkGzip;     bd: HCkBinData;     json: HCkJsonObject): wordbool; stdcall;` |
| `IsGzip` | method | `function CkGzip_IsGzip(objHandle: HCkGzip;     bd: HCkBinData): wordbool; stdcall;` |
| `LoadTaskCaller` | method | `function CkGzip_LoadTaskCaller(objHandle: HCkGzip;     task: HCkTask): wordbool; stdcall;` |
| `SetDt` | method | `function CkGzip_SetDt(objHandle: HCkGzip;     dt: HCkDateTime): wordbool; stdcall;` |
| `SetExtraData` | method | `function CkGzip_SetExtraData(objHandle: HCkGzip;     encodedData: PWideChar;     encoding: PWideChar): wordbool; stdcall;` |
| `UncompressBd` | method | `function CkGzip_UncompressBd(objHandle: HCkGzip;     binDat: HCkBinData): wordbool; stdcall;` |
| `UncompressBdToFile` | method | `function CkGzip_UncompressBdToFile(objHandle: HCkGzip;     bd: HCkBinData;     filePath: PWideChar): wordbool; stdcall;` |
| `UncompressFile` | method | `function CkGzip_UncompressFile(objHandle: HCkGzip;     srcPath: PWideChar;     destPath: PWideChar): wordbool; stdcall;` |
| `UncompressFileToString` | method | `function CkGzip_UncompressFileToString(objHandle: HCkGzip;     srcPath: PWideChar;     charset: PWideChar;     outStr: HCkString): wordbool; stdcall; function CkGzip__uncompressFileToString(objHandle: HCkGzip;     srcPath: PWideChar;     charset: PWideChar): PWideChar; stdcall;` |
| `UncompressStringENC` | method | `function CkGzip_UncompressStringENC(objHandle: HCkGzip;     inStr: PWideChar;     charset: PWideChar;     encoding: PWideChar;     outStr: HCkString): wordbool; stdcall; function CkGzip__uncompressStringENC(objHandle: HCkGzip;     inStr: PWideChar;     charset: PWideChar;     encoding: PWideChar): PWideChar; stdcall;` |
| `UnTarGz` | method | `function CkGzip_UnTarGz(objHandle: HCkGzip;     gzPath: PWideChar;     destDir: PWideChar;     bNoAbsolute: wordbool): wordbool; stdcall;` |
| `XfdlToXml` | method | `function CkGzip_XfdlToXml(objHandle: HCkGzip;     xfldData: PWideChar;     outStr: HCkString): wordbool; stdcall; function CkGzip__xfdlToXml(objHandle: HCkGzip;     xfldData: PWideChar): PWideChar; stdcall;` |

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 · delphidll · Gzip · AbortCurrent · property · read/write · since 9.5.0.58`

```pascal
function CkGzip_getAbortCurrent(objHandle: HCkGzip): wordbool; stdcall;
procedure CkGzip_putAbortCurrent(objHandle: HCkGzip; newPropVal: wordbool); stdcall;
```

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 · delphidll · Gzip · Comment · property · read/write`

```pascal
procedure CkGzip_getComment(objHandle: HCkGzip; outPropVal: HCkString); stdcall;
procedure CkGzip_putComment(objHandle: HCkGzip; newPropVal: PWideChar); stdcall;
function CkGzip__comment(objHandle: HCkGzip): PWideChar; stdcall;
```

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

### Gzip.CompressionLevel

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

```pascal
function CkGzip_getCompressionLevel(objHandle: HCkGzip): Integer; stdcall;
procedure CkGzip_putCompressionLevel(objHandle: HCkGzip; newPropVal: Integer); stdcall;
```

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.Filename

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

```pascal
procedure CkGzip_getFilename(objHandle: HCkGzip; outPropVal: HCkString); stdcall;
procedure CkGzip_putFilename(objHandle: HCkGzip; newPropVal: PWideChar); stdcall;
function CkGzip__filename(objHandle: HCkGzip): PWideChar; stdcall;
```

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 · delphidll · Gzip · HeartbeatMs · property · read/write`

```pascal
function CkGzip_getHeartbeatMs(objHandle: HCkGzip): Integer; stdcall;
procedure CkGzip_putHeartbeatMs(objHandle: HCkGzip; newPropVal: Integer); stdcall;
```

**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 · delphidll · Gzip · LastModStr · property · read/write`

```pascal
procedure CkGzip_getLastModStr(objHandle: HCkGzip; outPropVal: HCkString); stdcall;
procedure CkGzip_putLastModStr(objHandle: HCkGzip; newPropVal: PWideChar); stdcall;
function CkGzip__lastModStr(objHandle: HCkGzip): PWideChar; stdcall;
```

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 · delphidll · Gzip · UseCurrentDate · property · read/write`

```pascal
function CkGzip_getUseCurrentDate(objHandle: HCkGzip): wordbool; stdcall;
procedure CkGzip_putUseCurrentDate(objHandle: HCkGzip; newPropVal: wordbool); stdcall;
```

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 · delphidll · Gzip · CompressBd · method · since 9.5.0.67`

```pascal
function CkGzip_CompressBd(objHandle: HCkGzip;
    binDat: HCkBinData): wordbool; stdcall;
```

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 · delphidll · Gzip · CompressFile · method`

```pascal
function CkGzip_CompressFile(objHandle: HCkGzip;
    srcPath: PWideChar;
    destPath: PWideChar): wordbool; stdcall;
```

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 · delphidll · Gzip · CompressFile2 · method`

```pascal
function CkGzip_CompressFile2(objHandle: HCkGzip;
    srcPath: PWideChar;
    embeddedFilename: PWideChar;
    destPath: PWideChar): wordbool; stdcall;
```

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 · delphidll · Gzip · CompressFileBd · method · since 11.0.0`

```pascal
function CkGzip_CompressFileBd(objHandle: HCkGzip;
    filePath: PWideChar;
    bd: HCkBinData): wordbool; stdcall;
```

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.CompressSb

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

```pascal
function CkGzip_CompressSb(objHandle: HCkGzip;
    sb: HCkStringBuilder;
    charset: PWideChar;
    bd: HCkBinData): wordbool; stdcall;
```

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.CompressStringENC

`Chilkat 11.7.0 · delphidll · Gzip · CompressStringENC · method`

```pascal
function CkGzip_CompressStringENC(objHandle: HCkGzip;
    inStr: PWideChar;
    charset: PWideChar;
    encoding: PWideChar;
    outStr: HCkString): wordbool; stdcall;
function CkGzip__compressStringENC(objHandle: HCkGzip;
    inStr: PWideChar;
    charset: PWideChar;
    encoding: PWideChar): PWideChar; stdcall;
```

**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 True for success, False for failure.

See the notes about [PWideChar memory ownership and validity](https://www.chilkatsoft.com/delphi_pwidechar.asp).

### Gzip.CompressStringToFile

`Chilkat 11.7.0 · delphidll · Gzip · CompressStringToFile · method`

```pascal
function CkGzip_CompressStringToFile(objHandle: HCkGzip;
    inStr: PWideChar;
    destCharset: PWideChar;
    destPath: PWideChar): wordbool; stdcall;
```

**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 · delphidll · Gzip · GetGzipInfo · method · since 11.5.0`

```pascal
function CkGzip_GetGzipInfo(objHandle: HCkGzip;
    filePath: PWideChar;
    json: HCkJsonObject): wordbool; stdcall;
```

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 · delphidll · Gzip · GetGzipInfoBd · method · since 11.5.0`

```pascal
function CkGzip_GetGzipInfoBd(objHandle: HCkGzip;
    bd: HCkBinData;
    json: HCkJsonObject): wordbool; stdcall;
```

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 · delphidll · Gzip · IsGzip · method · since 11.0.0`

```pascal
function CkGzip_IsGzip(objHandle: HCkGzip;
    bd: HCkBinData): wordbool; stdcall;
```

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 · delphidll · Gzip · LoadTaskCaller · method · since 9.5.0.80`

```pascal
function CkGzip_LoadTaskCaller(objHandle: HCkGzip;
    task: HCkTask): wordbool; stdcall;
```

Loads the caller of the task's async method.

Returns True for success, False for failure.

### Gzip.SetDt

`Chilkat 11.7.0 · delphidll · Gzip · SetDt · method`

```pascal
function CkGzip_SetDt(objHandle: HCkGzip;
    dt: HCkDateTime): wordbool; stdcall;
```

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 · delphidll · Gzip · SetExtraData · method · since 11.0.0`

```pascal
function CkGzip_SetExtraData(objHandle: HCkGzip;
    encodedData: PWideChar;
    encoding: PWideChar): wordbool; stdcall;
```

**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 · delphidll · Gzip · UncompressBd · method · since 9.5.0.67`

```pascal
function CkGzip_UncompressBd(objHandle: HCkGzip;
    binDat: HCkBinData): wordbool; stdcall;
```

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 · delphidll · Gzip · UncompressBdToFile · method · since 11.0.0`

```pascal
function CkGzip_UncompressBdToFile(objHandle: HCkGzip;
    bd: HCkBinData;
    filePath: PWideChar): wordbool; stdcall;
```

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 · delphidll · Gzip · UncompressFile · method`

```pascal
function CkGzip_UncompressFile(objHandle: HCkGzip;
    srcPath: PWideChar;
    destPath: PWideChar): wordbool; stdcall;
```

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.UncompressFileToString

`Chilkat 11.7.0 · delphidll · Gzip · UncompressFileToString · method`

```pascal
function CkGzip_UncompressFileToString(objHandle: HCkGzip;
    srcPath: PWideChar;
    charset: PWideChar;
    outStr: HCkString): wordbool; stdcall;
function CkGzip__uncompressFileToString(objHandle: HCkGzip;
    srcPath: PWideChar;
    charset: PWideChar): PWideChar; stdcall;
```

**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 True for success, False for failure.

See the notes about [PWideChar memory ownership and validity](https://www.chilkatsoft.com/delphi_pwidechar.asp).

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

### Gzip.UncompressStringENC

`Chilkat 11.7.0 · delphidll · Gzip · UncompressStringENC · method`

```pascal
function CkGzip_UncompressStringENC(objHandle: HCkGzip;
    inStr: PWideChar;
    charset: PWideChar;
    encoding: PWideChar;
    outStr: HCkString): wordbool; stdcall;
function CkGzip__uncompressStringENC(objHandle: HCkGzip;
    inStr: PWideChar;
    charset: PWideChar;
    encoding: PWideChar): PWideChar; stdcall;
```

**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 True for success, False for failure.

See the notes about [PWideChar memory ownership and validity](https://www.chilkatsoft.com/delphi_pwidechar.asp).

### Gzip.UnTarGz

`Chilkat 11.7.0 · delphidll · Gzip · UnTarGz · method`

```pascal
function CkGzip_UnTarGz(objHandle: HCkGzip;
    gzPath: PWideChar;
    destDir: PWideChar;
    bNoAbsolute: wordbool): wordbool; stdcall;
```

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 · delphidll · Gzip · XfdlToXml · method`

```pascal
function CkGzip_XfdlToXml(objHandle: HCkGzip;
    xfldData: PWideChar;
    outStr: HCkString): wordbool; stdcall;
function CkGzip__xfdlToXml(objHandle: HCkGzip;
    xfldData: PWideChar): PWideChar; stdcall;
```

**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 True for success, False for failure.

See the notes about [PWideChar memory ownership and validity](https://www.chilkatsoft.com/delphi_pwidechar.asp).

## Events and callbacks

### Gzip.AbortCheck (event)

`Chilkat 11.7.0 · delphidll · Gzip · AbortCheck · event`

```pascal
function MyAbortCheck(): Integer; cdecl;
```

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. Return `True` to abort; return `False` to continue (not abort)

### Gzip.PercentDone (event)

`Chilkat 11.7.0 · delphidll · Gzip · PercentDone · event`

```pascal
function MyPercentDone(pctDone: Integer): Integer; cdecl;
```

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.

Return `True` to abort; return `False` to continue (not abort)

### Gzip.ProgressInfo (event)

`Chilkat 11.7.0 · delphidll · Gzip · ProgressInfo · event`

```pascal
procedure MyProgressInfo(name: PWideChar; value: PWideChar) cdecl;
```

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.

### Gzip.TaskCompleted (event)

`Chilkat 11.7.0 · delphidll · Gzip · TaskCompleted · event`

```pascal
procedure MyTaskCompleted(task: HCkTask) cdecl;
```

Called from the background thread when an asynchronous task completes.

## 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.

```pascal
function CkGzip_CompressBdAsync(objHandle: HCkGzip;
    binDat: HCkBinData): HCkTask; stdcall;
function CkGzip_CompressFileAsync(objHandle: HCkGzip;
    srcPath: PWideChar;
    destPath: PWideChar): HCkTask; stdcall;
function CkGzip_CompressFile2Async(objHandle: HCkGzip;
    srcPath: PWideChar;
    embeddedFilename: PWideChar;
    destPath: PWideChar): HCkTask; stdcall;
function CkGzip_CompressFileBdAsync(objHandle: HCkGzip;
    filePath: PWideChar;
    bd: HCkBinData): HCkTask; stdcall;
function CkGzip_CompressSbAsync(objHandle: HCkGzip;
    sb: HCkStringBuilder;
    charset: PWideChar;
    bd: HCkBinData): HCkTask; stdcall;
function CkGzip_CompressStringToFileAsync(objHandle: HCkGzip;
    inStr: PWideChar;
    destCharset: PWideChar;
    destPath: PWideChar): HCkTask; stdcall;
function CkGzip_UncompressBdAsync(objHandle: HCkGzip;
    binDat: HCkBinData): HCkTask; stdcall;
function CkGzip_UncompressBdToFileAsync(objHandle: HCkGzip;
    bd: HCkBinData;
    filePath: PWideChar): HCkTask; stdcall;
function CkGzip_UncompressFileAsync(objHandle: HCkGzip;
    srcPath: PWideChar;
    destPath: PWideChar): HCkTask; stdcall;
function CkGzip_UncompressFileToStringAsync(objHandle: HCkGzip;
    srcPath: PWideChar;
    charset: PWideChar): HCkTask; stdcall;
function CkGzip_UnTarGzAsync(objHandle: HCkGzip;
    gzPath: PWideChar;
    destDir: PWideChar;
    bNoAbsolute: wordbool): HCkTask; stdcall;
```

## Deprecated members — do not use in new code

| Member | Kind | Deprecated in | Use instead |
|---|---|---|---|
| `CompressFileToMem` | method | before 11.6.1 | — |
| `CompressMemory` | method | before 11.6.1 | — |
| `CompressMemToFile` | method | before 11.6.1 | — |
| `CompressString` | method | before 11.6.1 | — |
| `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 | — |
| `UncompressFileToMem` | method | before 11.6.1 | — |
| `UncompressMemory` | method | before 11.6.1 | — |
| `UncompressMemToFile` | method | before 11.6.1 | — |
| `UncompressString` | method | before 11.6.1 | — |
| `WriteFile` | method | before 11.6.1 | — |

## Related classes

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