feat: initial commit

This commit is contained in:
Rekai Nyangadzayi Musuka 2023-03-09 23:41:46 -06:00
commit 78f58a8fc7
3 changed files with 115 additions and 0 deletions

2
.gitignore vendored Normal file
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zig-cache/
zig-out/

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build.zig Normal file
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const std = @import("std");
// Although this function looks imperative, note that its job is to
// declaratively construct a build graph that will be executed by an external
// runner.
pub fn build(b: *std.Build) void {
// Standard target options allows 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
// between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
// set a preferred release mode, allowing the user to decide how to optimize.
const optimize = b.standardOptimizeOption(.{});
const lib = b.addStaticLibrary(.{
.name = "zba-util",
// In this case the main source file is merely a path, however, in more
// complicated build scripts, this could be a generated file.
.root_source_file = .{ .path = "src/lib.zig" },
.target = target,
.optimize = optimize,
});
// This declares intent for the library to be installed into the standard
// location when the user invokes the "install" step (the default step when
// running `zig build`).
lib.install();
// Creates a step for unit testing.
const main_tests = b.addTest(.{
.root_source_file = .{ .path = "src/main.zig" },
.target = target,
.optimize = optimize,
});
// This creates a build step. It will be visible in the `zig build --help` menu,
// and can be selected like this: `zig build test`
// This will evaluate the `test` step rather than the default, which is "install".
const test_step = b.step("test", "Run library tests");
test_step.dependOn(&main_tests.step);
}

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src/lib.zig Normal file
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const std = @import("std");
pub fn RingBuffer(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(.RingBuffer);
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) Error!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) return Error.buffer_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(self.read)];
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);
}
};
}