UnixCompress Zig Reference Documentation

UnixCompress

Current Version: 11.6.1

Chilkat.UnixCompress

Compress, uncompress, and unpack legacy UNIX .Z files.

Chilkat.UnixCompress provides UNIX compress and uncompress functionality for legacy .Z files. It supports file-based, memory-based, and string-based workflows, uses LZW compression, can unpack .tar.Z archives, and includes abort and progress-related support for longer-running operations.

Compress to .Z

Compress files, memory data, or strings into UNIX .Z format using LZW compression.

Uncompress .Z data

Expand UNIX-compressed data back to files, memory, byte arrays, or text depending on the application workflow.

File workflows

Compress and uncompress directly between input and output files when working with existing filesystem data.

Memory workflows

Work with compressed or uncompressed byte data in memory when temporary files are not desired.

String workflows

Compress and uncompress text using an explicit character set so string data round-trips correctly.

Unpack tar.Z archives

Use UnTarZ to decompress and extract legacy .tar.Z archives in a single workflow.

Common pattern: Use UnixCompress when the data is in classic UNIX .Z format or when a .tar.Z archive must be unpacked. Use Chilkat.Gzip for .gz and .tar.gz files, Chilkat.Bz2 for .bz2 files, and Chilkat.Compression for raw compression algorithms and general-purpose compression workflows.

Object Creation

// Add the package once:
//     zig fetch --save https://chilkatdownload.com/11.6.1/chilkat-zig-11.6.1.tar.gz
// and in build.zig:
//     const chilkat = b.dependency("chilkat", .{ .target = target, .optimize = optimize });
//     exe.root_module.addImport("chilkat", chilkat.module("chilkat"));
const chilkat = @import("chilkat");

// Once per process, before any other Chilkat call:
try chilkat.unlockBundle("Anything for 30-day trial");

const unix_compress = try chilkat.UnixCompress.init();
defer unix_compress.deinit();
pub fn init() Allocator.Error!UnixCompress

Creates the underlying native Chilkat object. UnixCompress is a one-pointer struct passed by value; copying it copies the handle (two names for one object). Returns error.OutOfMemory if the library could not allocate the object. Use an object from one thread at a time; it may be handed from one thread to another.

pub fn deinit(self: UnixCompress) void

Releases the native object. Call it exactly once per object (usually with defer); the handle is invalid afterwards. Objects returned by methods are owned by the caller too and are released the same way.

pub fn fromHandle(h: *chilkat.c.CkUnixCompress.HCkUnixCompress) UnixCompress

Wraps a handle obtained from the C API (chilkat.c.CkUnixCompress), taking ownership of it. The struct's handle field goes the other way, for anything the Zig API does not cover.

Errors and memory

Methods that can fail return an error union: a method whose only outcome is success or failure returns Error!void; a method producing a string returns (Error || Allocator.Error)![:0]u8; a method producing an object returns Error!T. chilkat.Error is error{ChilkatFailed}; the reason for a failure is in getLastErrorText, and the object remains usable. Properties never fail, and methods that answer a question (hasMember, isUnlocked, ...) return a plain bool.

String arguments are [:0]const u8 (UTF-8; string literals can be passed as is). String results are copies allocated with the allocator argument and owned by the caller, so they stay valid across later calls on the same object.

const text = unix_compress.someMethod(allocator, ...) catch |err| {
    const why = try unix_compress.getLastErrorText(allocator);
    defer allocator.free(why);
    std.debug.print("{s}\n", .{why});
    return err;
};
defer allocator.free(text);

Properties

AbortCurrent
// read/write
pub fn getAbortCurrent(self: UnixCompress) bool
pub fn setAbortCurrent(self: UnixCompress, value: bool) void
Introduced in version 9.5.0.58

When set to true, causes the currently running method to abort. Methods that always finish quickly (i.e.have no length file operations or network communications) are not affected. If no method is running, then this property is automatically reset to false when the next method is called. When the abort occurs, this property is reset to false. Both synchronous and asynchronous method calls can be aborted. (A synchronous method call could be aborted by setting this property from a separate thread.)

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DebugLogFilePath
// read/write
pub fn getDebugLogFilePath(self: UnixCompress, allocator: Allocator) Allocator.Error![:0]u8
pub fn setDebugLogFilePath(self: UnixCompress, value: [:0]const u8) void

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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HeartbeatMs
// read/write
pub fn getHeartbeatMs(self: UnixCompress) i32
pub fn setHeartbeatMs(self: UnixCompress, value: i32) void

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

More Information and Examples
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LastErrorHtml
// read-only
pub fn getLastErrorHtml(self: UnixCompress, allocator: Allocator) Allocator.Error![:0]u8

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
// read-only
pub fn getLastErrorText(self: UnixCompress, allocator: Allocator) Allocator.Error![:0]u8

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
// read-only
pub fn getLastErrorXml(self: UnixCompress, allocator: Allocator) Allocator.Error![:0]u8

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
// read/write
pub fn getLastMethodSuccess(self: UnixCompress) bool
pub fn setLastMethodSuccess(self: UnixCompress, value: bool) void

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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VerboseLogging
// read/write
pub fn getVerboseLogging(self: UnixCompress) bool
pub fn setVerboseLogging(self: UnixCompress, value: bool) void

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
// read-only
pub fn getVersion(self: UnixCompress, allocator: Allocator) Allocator.Error![:0]u8

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

More Information and Examples
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Methods

CompressFile
pub fn compressFile(self: UnixCompress, in_filename: [:0]const u8, dest_path: [:0]const u8) Error!void

Compresses a file to create a UNIX compressed file (.Z). This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.

Returns error.ChilkatFailed on failure; getLastErrorText explains why.

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CompressStringToFile
pub fn compressStringToFile(self: UnixCompress, in_str: [:0]const u8, charset: [:0]const u8, dest_path: [:0]const u8) Error!void

Unix compresses and creates a .Z file from string data. The charset specifies the character encoding used for the byte representation of the characters when compressed. The charset can be any one of a large number of character encodings, such as utf-8, iso-8859-1, Windows-1252, ucs-2, etc.

Returns error.ChilkatFailed on failure; getLastErrorText explains why.

More Information and Examples
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UncompressFile
pub fn uncompressFile(self: UnixCompress, in_filename: [:0]const u8, dest_path: [:0]const u8) Error!void

Uncompresses a .Z file. (This compression uses the LZW (Lempel-Ziv-Welch) compression algorithm.)

Returns error.ChilkatFailed on failure; getLastErrorText explains why.

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UncompressFileToString
pub fn uncompressFileToString(self: UnixCompress, allocator: Allocator, z_filename: [:0]const u8, charset: [:0]const u8) (Error || Allocator.Error)![:0]u8

Uncompresses a .Z file that contains a text file. The contents of the text file are returned as a string. The character encoding of the text file is specified by charset. Typical charsets are iso-8859-1, utf-8, windows-1252, shift_JIS, big5, etc.

Returns error.ChilkatFailed on failure; getLastErrorText explains why. The string is allocated with allocator and owned by the caller (defer allocator.free(s)).

More Information and Examples
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UnTarZ
pub fn unTarZ(self: UnixCompress, z_filename: [:0]const u8, dest_dir: [:0]const u8, b_no_absolute: bool) Error!void

Unpacks a .tar.Z file. The decompress and untar occur in streaming mode. There are no temporary files and the memory footprint is constant (and small) while untarring.

Returns error.ChilkatFailed on failure; getLastErrorText explains why.

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Events

All Chilkat methods are synchronous: the call returns when the work is done. During a call, UnixCompress raises three events so your program can show progress and offer a way out. Declare any subset of abortCheck, percentDone and progressInfo in a struct of your own and install a pointer to it with setEventHandler:

const Progress = struct {
    pub fn percentDone(_: *Progress, pct: i32) bool {
        std.debug.print("{d}%\n", .{pct});
        return false; // return true to abort the method in progress
    }
    pub fn progressInfo(_: *Progress, name: [:0]const u8, value: [:0]const u8) void {
        std.debug.print("{s}: {s}\n", .{ name, value });
    }
};

var progress = Progress{};
unix_compress.setEventHandler(&progress); // progress must outlive the installation
defer unix_compress.clearEventHandler();
unix_compress.setHeartbeatMs(250); // abortCheck 4 times per second during Chilkat calls
pub fn setEventHandler(self: UnixCompress, handler: anytype) void

Installs handler, a pointer to any struct, as the receiver of this object's events, replacing any handler installed earlier. The dispatch is resolved at compile time: only the methods the struct declares are called, and a struct declaring none of the three is a compile error. The struct must stay alive, at the same address, until clearEventHandler or deinit.

pub fn clearEventHandler(self: UnixCompress) void

Removes the handler; events are no longer delivered.

AbortCheck fires at regular intervals controlled by the HeartbeatMs property (0, the default, disables it); PercentDone fires when an operation's completion percentage is known; ProgressInfo delivers named progress values. Returning true from abortCheck or percentDone aborts the running method, which then returns error.ChilkatFailed.

Events fire on the thread that called the method, before that method returns. To abort a long operation from another thread, have abortCheck read a std.atomic.Value(bool), or set the object's AbortCurrent property.

AbortCheck
// handler struct method (optional); install with setEventHandler
pub fn abortCheck(self: *T) bool

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.

More Information and Examples

Example

const Abort = struct {
    stop: std.atomic.Value(bool) = .init(false),
    pub fn abortCheck(self: *Abort) bool {
        return self.stop.load(.acquire); // another thread may call abort.stop.store(true, .release)
    }
};

var abort = Abort{};
unix_compress.setHeartbeatMs(250); // call abortCheck 4 times per second
unix_compress.setEventHandler(&abort);
defer unix_compress.clearEventHandler();
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PercentDone
// handler struct method (optional); install with setEventHandler
pub fn percentDone(self: *T, pct: i32) bool

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.

More Information and Examples

Example

const Progress = struct {
    pub fn percentDone(_: *Progress, pct: i32) bool {
        // pct ranges from 1 to 100.
        std.debug.print("Percent done: {d}\n", .{pct});
        return false; // return true to abort the method in progress
    }
};

var progress = Progress{};
unix_compress.setEventHandler(&progress);
defer unix_compress.clearEventHandler();
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ProgressInfo
// handler struct method (optional); install with setEventHandler
pub fn progressInfo(self: *T, name: [:0]const u8, value: [:0]const u8) void

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.

More Information and Examples

Example

const Info = struct {
    pub fn progressInfo(_: *Info, name: [:0]const u8, value: [:0]const u8) void {
        std.debug.print("{s}: {s}\n", .{ name, value });
    }
};

var info = Info{};
unix_compress.setEventHandler(&info);
defer unix_compress.clearEventHandler();
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