Bz2 Zig Reference Documentation
Bz2
Current Version: 11.6.1
Chilkat.Bz2 provides BZip2 compression and decompression for files, memory buffers, and BinData. It can create standard .bz2 file images, decompress .bz2 content back to its original bytes, and support abortable long-running operations.
For an extended overview, see Bz2 Class Overview
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 bz2 = try chilkat.Bz2.init();
defer bz2.deinit();Creates the underlying native Chilkat object. Bz2 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.
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.
Wraps a handle obtained from the C API (chilkat.c.CkBz2), 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 = bz2.someMethod(allocator, ...) catch |err| {
const why = try bz2.getLastErrorText(allocator);
defer allocator.free(why);
std.debug.print("{s}\n", .{why});
return err;
};
defer allocator.free(text);
Properties
AbortCurrent
pub fn getAbortCurrent(self: Bz2) bool
pub fn setAbortCurrent(self: Bz2, value: bool) void
Set this property to to request cancellation of the compression or decompression operation currently executing on this object. Long-running operations check the request periodically; an operation that finishes quickly may complete before the request is observed.true
A synchronous call can be cancelled by setting this property from another thread. After cancellation is processed, Chilkat resets the property to . If no operation is running, a previously set value is cleared when the next method begins.false
LastErrorText to determine the final outcome.DebugLogFilePath
pub fn getDebugLogFilePath(self: Bz2, allocator: Allocator) Allocator.Error![:0]u8
pub fn setDebugLogFilePath(self: Bz2, 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.
HeartbeatMs
pub fn getHeartbeatMs(self: Bz2) i32
pub fn setHeartbeatMs(self: Bz2, value: i32) void
Specifies the interval, in milliseconds, between AbortCheck event callbacks during supported long-running compression and decompression operations. The default is 0, which disables AbortCheck callbacks.
Set a positive value, such as 200, when the application needs periodic opportunities to request cancellation. The interval is approximate; callbacks occur only while an operation is at a point where progress events can be delivered.
AbortCheck handler, set the callback's abort value to request termination. A synchronous method may also be cancelled from another thread by setting AbortCurrent to true.LastErrorHtml
pub fn getLastErrorHtml(self: Bz2, 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.
topLastErrorText
pub fn getLastErrorText(self: Bz2, 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.
LastErrorXml
pub fn getLastErrorXml(self: Bz2, 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.
topLastMethodSuccess
pub fn getLastMethodSuccess(self: Bz2) bool
pub fn setLastMethodSuccess(self: Bz2, 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.
VerboseLogging
pub fn getVerboseLogging(self: Bz2) bool
pub fn setVerboseLogging(self: Bz2, 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.
Version
pub fn getVersion(self: Bz2, allocator: Allocator) Allocator.Error![:0]u8
Methods
CompressBd
Compresses the current contents of bd in place. On success, the BinData no longer contains the original bytes; it contains the complete standard BZip2 stream that may be saved with a .bz2 extension.
Returns error.ChilkatFailed on failure; getLastErrorText explains why.
CompressFile
Reads the file at in_filename and writes its compressed bytes as a standard BZip2 stream to the file at to_path. The output is conventionally given a .bz2 extension.
Both arguments must identify files, not directories. They may be absolute or relative paths, for example data/report.txt and data/report.txt.bz2.
.bz2 file represents one compressed byte stream. It does not store the original filename, directory path, timestamps, permissions, or multiple archive entries. Formats such as .tar.bz2 first combine files in a TAR archive and then compress that TAR stream with BZip2.Returns error.ChilkatFailed on failure; getLastErrorText explains why.
UncompressBd
Decompresses the BZip2 stream currently contained in bd in place. On success, the BinData is replaced with the original uncompressed bytes.
bd must contain a complete, valid BZip2 stream, such as the bytes of a .bz2 file or the output of CompressBd. This method operates on binary data and does not perform character-set conversion.Returns error.ChilkatFailed on failure; getLastErrorText explains why.
UncompressFile
Reads the BZip2 stream from the file at in_filename, decompresses it, and writes the original uncompressed bytes to the file at to_path.
Both arguments must identify files, not directories. Chilkat does not derive the destination name from the .bz2 filename because the BZip2 stream does not contain the original filename.
.bz2 file normally contains a single compressed byte stream rather than a collection of named files.Returns error.ChilkatFailed on failure; getLastErrorText explains why.
Events
All Chilkat methods are synchronous: the call returns when the work is done. During a call, Bz2 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{};
bz2.setEventHandler(&progress); // progress must outlive the installation
defer bz2.clearEventHandler();
bz2.setHeartbeatMs(250); // abortCheck 4 times per second during Chilkat callsInstalls 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.
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
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.
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{};
bz2.setHeartbeatMs(250); // call abortCheck 4 times per second
bz2.setEventHandler(&abort);
defer bz2.clearEventHandler();PercentDone
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.
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{};
bz2.setEventHandler(&progress);
defer bz2.clearEventHandler();ProgressInfo
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.
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{};
bz2.setEventHandler(&info);
defer bz2.clearEventHandler();