chore: update to zig 0.15.1

.gitignore

@@ -1,2 +1,2 @@
-zig-cache/
+.zig-cache/
 zig-out/

build.zig

@@ -1,47 +1,68 @@
 const std = @import("std");
 
-// Although this function looks imperative, note that its job is to
+// Although this function looks imperative, it does not perform the build
-// declaratively construct a build graph that will be executed by an external
+// directly and instead it mutates the build graph (`b`) that will be then
-// runner.
+// executed by an external runner. The functions in `std.Build` implement a DSL
+// for defining build steps and express dependencies between them, allowing the
+// build runner to parallelize the build automatically (and the cache system to
+// know when a step doesn't need to be re-run).
 pub fn build(b: *std.Build) void {
-    // Standard target options allows the person running `zig build` to choose
+    // Standard target options allow the person running `zig build` to choose
     // what target to build for. Here we do not override the defaults, which
     // means any target is allowed, and the default is native. Other options
     // for restricting supported target set are available.
     const target = b.standardTargetOptions(.{});
 
-    // Standard optimization options allow the person running `zig build` to select
+    // It's also possible to define more custom flags to toggle optional features
-    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
+    // of this build script using `b.option()`. All defined flags (including
-    // set a preferred release mode, allowing the user to decide how to optimize.
+    // target and optimize options) will be listed when running `zig build --help`
-    const optimize = b.standardOptimizeOption(.{});
+    // in this directory.
 
-    const lib = b.addStaticLibrary(.{
+    // This creates a module, which represents a collection of source files alongside
-        .name = "zba-util",
+    // some compilation options, such as optimization mode and linked system libraries.
-        // In this case the main source file is merely a path, however, in more
+    // Zig modules are the preferred way of making Zig code available to consumers.
-        // complicated build scripts, this could be a generated file.
+    // addModule defines a module that we intend to make available for importing
-        .root_source_file = .{ .path = "src/lib.zig" },
+    // to our consumers. We must give it a name because a Zig package can expose
+    // multiple modules and consumers will need to be able to specify which
+    // module they want to access.
+    const mod = b.addModule("zba_util", .{
+        // The root source file is the "entry point" of this module. Users of
+        // this module will only be able to access public declarations contained
+        // in this file, which means that if you have declarations that you
+        // intend to expose to consumers that were defined in other files part
+        // of this module, you will have to make sure to re-export them from
+        // the root file.
+        .root_source_file = b.path("src/lib.zig"),
+        // Later on we'll use this module as the root module of a test executable
+        // which requires us to specify a target.
         .target = target,
-        .optimize = optimize,
     });
 
-    // This declares intent for the library to be installed into the standard
+    // Creates an executable that will run `test` blocks from the provided module.
-    // location when the user invokes the "install" step (the default step when
+    // Here `mod` needs to define a target, which is why earlier we made sure to
-    // running `zig build`).
+    // set the releative field.
-    b.installArtifact(lib);
+    const mod_tests = b.addTest(.{
-
+        .root_module = mod,
-    // Creates a step for unit testing. This only builds the test executable
-    // but does not run it.
-    const main_tests = b.addTest(.{
-        .root_source_file = .{ .path = "src/lib.zig" },
-        .target = target,
-        .optimize = optimize,
     });
 
-    const run_main_tests = b.addRunArtifact(main_tests);
+    // A run step that will run the test executable.
+    const run_mod_tests = b.addRunArtifact(mod_tests);
 
-    // This creates a build step. It will be visible in the `zig build --help` menu,
+    // A top level step for running all tests. dependOn can be called multiple
-    // and can be selected like this: `zig build test`
+    // times and since the two run steps do not depend on one another, this will
-    // This will evaluate the `test` step rather than the default, which is "install".
+    // make the two of them run in parallel.
-    const test_step = b.step("test", "Run library tests");
+    const test_step = b.step("test", "Run tests");
-    test_step.dependOn(&run_main_tests.step);
+    test_step.dependOn(&run_mod_tests.step);
+
+    // Just like flags, top level steps are also listed in the `--help` menu.
+    //
+    // The Zig build system is entirely implemented in userland, which means
+    // that it cannot hook into private compiler APIs. All compilation work
+    // orchestrated by the build system will result in other Zig compiler
+    // subcommands being invoked with the right flags defined. You can observe
+    // these invocations when one fails (or you pass a flag to increase
+    // verbosity) to validate assumptions and diagnose problems.
+    //
+    // Lastly, the Zig build system is relatively simple and self-contained,
+    // and reading its source code will allow you to master it.
 }

build.zig.zon

@@ -0,0 +1,81 @@
+.{
+    // This is the default name used by packages depending on this one. For
+    // example, when a user runs `zig fetch --save <url>`, this field is used
+    // as the key in the `dependencies` table. Although the user can choose a
+    // different name, most users will stick with this provided value.
+    //
+    // It is redundant to include "zig" in this name because it is already
+    // within the Zig package namespace.
+    .name = .zba_util,
+    // This is a [Semantic Version](https://semver.org/).
+    // In a future version of Zig it will be used for package deduplication.
+    .version = "0.0.0",
+    // Together with name, this represents a globally unique package
+    // identifier. This field is generated by the Zig toolchain when the
+    // package is first created, and then *never changes*. This allows
+    // unambiguous detection of one package being an updated version of
+    // another.
+    //
+    // When forking a Zig project, this id should be regenerated (delete the
+    // field and run `zig build`) if the upstream project is still maintained.
+    // Otherwise, the fork is *hostile*, attempting to take control over the
+    // original project's identity. Thus it is recommended to leave the comment
+    // on the following line intact, so that it shows up in code reviews that
+    // modify the field.
+    .fingerprint = 0xc252e6a789d0ad48, // Changing this has security and trust implications.
+    // Tracks the earliest Zig version that the package considers to be a
+    // supported use case.
+    .minimum_zig_version = "0.15.1",
+    // This field is optional.
+    // Each dependency must either provide a `url` and `hash`, or a `path`.
+    // `zig build --fetch` can be used to fetch all dependencies of a package, recursively.
+    // Once all dependencies are fetched, `zig build` no longer requires
+    // internet connectivity.
+    .dependencies = .{
+        // See `zig fetch --save <url>` for a command-line interface for adding dependencies.
+        //.example = .{
+        //    // When updating this field to a new URL, be sure to delete the corresponding
+        //    // `hash`, otherwise you are communicating that you expect to find the old hash at
+        //    // the new URL. If the contents of a URL change this will result in a hash mismatch
+        //    // which will prevent zig from using it.
+        //    .url = "https://example.com/foo.tar.gz",
+        //
+        //    // This is computed from the file contents of the directory of files that is
+        //    // obtained after fetching `url` and applying the inclusion rules given by
+        //    // `paths`.
+        //    //
+        //    // This field is the source of truth; packages do not come from a `url`; they
+        //    // come from a `hash`. `url` is just one of many possible mirrors for how to
+        //    // obtain a package matching this `hash`.
+        //    //
+        //    // Uses the [multihash](https://multiformats.io/multihash/) format.
+        //    .hash = "...",
+        //
+        //    // When this is provided, the package is found in a directory relative to the
+        //    // build root. In this case the package's hash is irrelevant and therefore not
+        //    // computed. This field and `url` are mutually exclusive.
+        //    .path = "foo",
+        //
+        //    // When this is set to `true`, a package is declared to be lazily
+        //    // fetched. This makes the dependency only get fetched if it is
+        //    // actually used.
+        //    .lazy = false,
+        //},
+    },
+    // Specifies the set of files and directories that are included in this package.
+    // Only files and directories listed here are included in the `hash` that
+    // is computed for this package. Only files listed here will remain on disk
+    // when using the zig package manager. As a rule of thumb, one should list
+    // files required for compilation plus any license(s).
+    // Paths are relative to the build root. Use the empty string (`""`) to refer to
+    // the build root itself.
+    // A directory listed here means that all files within, recursively, are included.
+    .paths = .{
+        "build.zig",
+        "build.zig.zon",
+        "src",
+        // For example...
+        //"LICENSE",
+        //"README.md",
+    },
+}

src/lib.zig

@@ -1,101 +1,12 @@
 const std = @import("std");
 const Log2Int = std.math.Log2Int;
-
+const Allocator = std.mem.Allocator;
-const EmuMessage = enum { Pause, Resume, Quit };
-const GuiMessage = enum { Paused, Quit };
-
-pub const TwoWayChannel = struct {
-    const Self = @This();
-
-    emu: Channel(EmuMessage),
-    gui: Channel(GuiMessage),
-
-    pub fn init(items: []u8) Self {
-        comptime std.debug.assert(@sizeOf(EmuMessage) == @sizeOf(GuiMessage));
-        comptime std.debug.assert(@sizeOf(@typeInfo([]u8).Pointer.child) == @sizeOf(EmuMessage));
-
-        std.debug.assert(items.len % 2 == 0);
-
-        const left = @ptrCast([*]EmuMessage, items)[0 .. items.len / 2];
-        const right = @ptrCast([*]GuiMessage, items)[items.len / 2 .. items.len];
-
-        return .{ .emu = Channel(EmuMessage).init(left), .gui = Channel(GuiMessage).init(right) };
-    }
-};
-
-fn Channel(comptime T: type) type {
-    return struct {
-        const Self = @This();
-        const Index = usize;
-
-        const Atomic = std.atomic.Atomic;
-
-        const max_capacity = (@as(Index, 1) << @typeInfo(Index).Int.bits - 1) - 1; // half the range of index type
-        const log = std.log.scoped(.Channel);
-
-        read: Atomic(Index),
-        write: Atomic(Index),
-        buf: []T,
-
-        const Error = error{buffer_full};
-
-        pub fn init(buf: []T) Self {
-            std.debug.assert(std.math.isPowerOfTwo(buf.len)); // capacity must be a power of two
-            std.debug.assert(buf.len <= max_capacity);
-
-            return .{
-                .read = Atomic(Index).init(0),
-                .write = Atomic(Index).init(0),
-                .buf = buf,
-            };
-        }
-
-        pub fn push(self: *Self, value: T) void {
-            const read_idx = self.read.load(.Acquire);
-            const write_idx = self.write.load(.Acquire);
-
-            // Check to see if Queue is full
-            if (write_idx - read_idx == self.buf.len) @panic("Channel: Buffer is full");
-
-            self.buf[self.mask(write_idx)] = value;
-
-            std.atomic.fence(.Release);
-            self.write.store(write_idx + 1, .Release);
-        }
-
-        pub fn pop(self: *Self) ?T {
-            const read_idx = self.read.load(.Acquire);
-            const write_idx = self.write.load(.Acquire);
-
-            if (read_idx == write_idx) return null;
-
-            std.atomic.fence(.Acquire);
-            const value = self.buf[self.mask(read_idx)];
-
-            std.atomic.fence(.Release);
-            self.read.store(read_idx + 1, .Release);
-
-            return value;
-        }
-
-        pub fn len(self: *const Self) Index {
-            const read_idx = self.read.load(.Acquire);
-            const write_idx = self.write.load(.Acquire);
-
-            return write_idx - read_idx;
-        }
-
-        fn mask(self: *const Self, idx: Index) Index {
-            return idx & (self.buf.len - 1);
-        }
-    };
-}
 
 pub fn RingBuffer(comptime T: type) type {
     return struct {
         const Self = @This();
         const Index = usize;
-        const max_capacity = (@as(Index, 1) << @typeInfo(Index).Int.bits - 1) - 1; // half the range of index type
+        const max_capacity = (@as(Index, 1) << @typeInfo(Index).int.bits - 1) - 1; // half the range of index type
 
         const log = std.log.scoped(.RingBuffer);
 
@@ -109,8 +20,6 @@ pub fn RingBuffer(comptime T: type) type {
             std.debug.assert(std.math.isPowerOfTwo(buf.len)); // capacity must be a power of two
             std.debug.assert(buf.len <= max_capacity);
 
-            @memset(buf, 0);
-
             return .{ .read = 0, .write = 0, .buf = buf };
         }
 
@@ -130,7 +39,7 @@ pub fn RingBuffer(comptime T: type) type {
 
         /// Returns the number of entries read
         pub fn copy(self: *const Self, cpy: []T) Index {
-            const count = std.math.min(self.len(), cpy.len);
+            const count = @min(self.len(), cpy.len);
             var start: Index = self.read;
 
             for (cpy, 0..) |*v, i| {
@@ -164,20 +73,20 @@ pub fn RingBuffer(comptime T: type) type {
 // Sign-Extend value of type `T` to type `U`
 pub fn sext(comptime T: type, comptime U: type, value: T) T {
     // U must have less bits than T
-    comptime std.debug.assert(@typeInfo(U).Int.bits <= @typeInfo(T).Int.bits);
+    comptime std.debug.assert(@typeInfo(U).int.bits <= @typeInfo(T).int.bits);
 
-    const iT = std.meta.Int(.signed, @typeInfo(T).Int.bits);
+    const iT = std.meta.Int(.signed, @typeInfo(T).int.bits);
-    const ExtU = if (@typeInfo(U).Int.signedness == .unsigned) T else iT;
+    const ExtU = if (@typeInfo(U).int.signedness == .unsigned) T else iT;
-    const shift_amt = @intCast(Log2Int(T), @typeInfo(T).Int.bits - @typeInfo(U).Int.bits);
+    const shift_amt: Log2Int(T) = @intCast(@typeInfo(T).int.bits - @typeInfo(U).int.bits);
 
-    return @bitCast(T, @bitCast(iT, @as(ExtU, @truncate(U, value)) << shift_amt) >> shift_amt);
+    return @bitCast(@as(iT, @bitCast(@as(ExtU, @as(U, @truncate(value))) << shift_amt)) >> shift_amt);
 }
 
 /// See https://godbolt.org/z/W3en9Eche
 pub inline fn rotr(comptime T: type, x: T, r: anytype) T {
-    if (@typeInfo(T).Int.signedness == .signed)
+    if (@typeInfo(T).int.signedness == .signed)
         @compileError("cannot rotate signed integer");
 
-    const ar = @intCast(Log2Int(T), @mod(r, @typeInfo(T).Int.bits));
+    const ar: Log2Int(T) = @intCast(@mod(r, @typeInfo(T).int.bits));
     return x >> ar | x << (1 +% ~ar);
 }