commit

build.zig

@@ -15,19 +15,6 @@ pub fn build(b: *std.Build) void {
     // set a preferred release mode, allowing the user to decide how to optimize.
     const optimize = b.standardOptimizeOption(.{});
 
-    // This creates a "module", which represents a collection of source files alongside
-    // some compilation options, such as optimization mode and linked system libraries.
-    // Every executable or library we compile will be based on one or more modules.
-    const lib_mod = b.createModule(.{
-        // `root_source_file` is the Zig "entry point" of the module. If a module
-        // only contains e.g. external object files, you can make this `null`.
-        // 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 = b.path("src/root.zig"),
-        .target = target,
-        .optimize = optimize,
-    });
-
     // We will also create a module for our other entry point, 'main.zig'.
     const exe_mod = b.createModule(.{
         // `root_source_file` is the Zig "entry point" of the module. If a module
@@ -37,31 +24,17 @@ pub fn build(b: *std.Build) void {
         .root_source_file = b.path("src/main.zig"),
         .target = target,
         .optimize = optimize,
+        .link_libc = true,
     });
 
-    // Modules can depend on one another using the `std.Build.Module.addImport` function.
+    exe_mod.linkSystemLibrary("libpipewire-0.3", .{
-    // This is what allows Zig source code to use `@import("foo")` where 'foo' is not a
+        .needed = true,
-    // file path. In this case, we set up `exe_mod` to import `lib_mod`.
-    exe_mod.addImport("zig_lib", lib_mod);
-
-    // Now, we will create a static library based on the module we created above.
-    // This creates a `std.Build.Step.Compile`, which is the build step responsible
-    // for actually invoking the compiler.
-    const lib = b.addLibrary(.{
-        .linkage = .static,
-        .name = "zig",
-        .root_module = lib_mod,
     });
 
-    // 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`).
-    b.installArtifact(lib);
-
     // This creates another `std.Build.Step.Compile`, but this one builds an executable
     // rather than a static library.
     const exe = b.addExecutable(.{
-        .name = "zig",
+        .name = "recorder",
         .root_module = exe_mod,
     });
 
@@ -93,14 +66,6 @@ pub fn build(b: *std.Build) void {
     const run_step = b.step("run", "Run the app");
     run_step.dependOn(&run_cmd.step);
 
-    // Creates a step for unit testing. This only builds the test executable
-    // but does not run it.
-    const lib_unit_tests = b.addTest(.{
-        .root_module = lib_mod,
-    });
-
-    const run_lib_unit_tests = b.addRunArtifact(lib_unit_tests);
-
     const exe_unit_tests = b.addTest(.{
         .root_module = exe_mod,
     });
@@ -111,6 +76,5 @@ pub fn build(b: *std.Build) void {
     // the `zig build --help` menu, providing a way for the user to request
     // running the unit tests.
     const test_step = b.step("test", "Run unit tests");
-    test_step.dependOn(&run_lib_unit_tests.step);
     test_step.dependOn(&run_exe_unit_tests.step);
 }

src/main.zig

@@ -1,46 +1,180 @@
-//! By convention, main.zig is where your main function lives in the case that
+const data_struct = struct {
-//! you are building an executable. If you are making a library, the convention
+    loop: ?*pipewire.pw_main_loop,
-//! is to delete this file and start with root.zig instead.
+    stream: ?*pipewire.pw_stream,
+    format: pipewire.spa_audio_info,
+    move: u1,
+};
+
+/// our data processing function is in general:
+///
+///  struct pw_buffer *b;
+///  b = pw_stream_dequeue_buffer(stream);
+///
+///  .. consume stuff in the buffer ...
+///
+///  pw_stream_queue_buffer(stream, b);
+export fn on_process(userdata: ?*anyopaque) void {
+    const data: *data_struct = @ptrCast(@alignCast(userdata));
+    const b_optional: ?*pipewire.pw_buffer = pipewire.pw_stream_dequeue_buffer(data.stream);
+    var buf: *pipewire.spa_buffer = undefined;
+
+    var samples_optional: ?[*]f32 = undefined;
+    var max: f32 = undefined;
+
+    var c: u32 = 0;
+    var n: u32 = undefined;
+    var n_channels: u32 = undefined;
+    var n_samples: u32 = undefined;
+    var peak: u32 = undefined;
+
+    if (b_optional) |b| {
+        buf = b.buffer;
+        samples_optional = @ptrCast(@alignCast(buf.datas[0].data));
+        if (samples_optional) |samples| {
+            n_channels = data.format.info.raw.channels;
+            n_samples = buf.datas[0].chunk.*.size / @sizeOf(f32);
+
+            if (data.move != @as(u1, 0))
+                _ = pipewire.fprintf(pipewire.stdout, "%c[%dA", @as(u8, 0x1b), n_channels + 1);
+
+            _ = pipewire.fprintf(pipewire.stdout, "captured %d samples\n", n_samples / n_channels);
+            while (c < data.format.info.raw.channels) : (c += 0) {
+                max = 0.0;
+                n = c;
+                while (n < n_samples) : (n += n_channels)
+                    max = @max(max, @abs(samples[n]));
+
+                peak = @bitCast(@min(@max(max * 30.0, 0.0), 39.0));
+
+                _ = pipewire.fprintf(
+                    pipewire.stdout,
+                    "channel %d: |%*s%*s| peak:%f\n",
+                    c,
+                    peak + 1,
+                    "*",
+                    40 - peak,
+                    "",
+                    max,
+                );
+            }
+            data.move = @intFromBool(true);
+            _ = pipewire.fflush(pipewire.stdout);
+
+            _ = pipewire.pw_stream_queue_buffer(data.stream, b);
+        }
+    } else {
+        pw_log_warn("out of buffers: %m");
+    }
+}
+
+/// Be notified when the stream param changes. We're only looking at the format changes.
+export fn on_stream_param_changed(_data: ?*anyopaque, id: u32, param_optional: ?*const pipewire.spa_pod) void {
+    const data: *data_struct = @ptrCast(@alignCast(_data));
+
+    // NULL means to clear the format
+    if (param_optional) |param| {
+        if (id != pipewire.SPA_PARAM_Format) {
+            if (pipewire.spa_format_parse(param, &data.format.media_type, &data.format.media_subtype) >= 0) {
+                if (data.format.media_type == pipewire.SPA_MEDIA_TYPE_audio and data.format.media_subtype == pipewire.SPA_MEDIA_SUBTYPE_raw) {
+                    _ = pipewire.spa_format_audio_raw_parse(param, &data.format.info.raw);
+                    _ = pipewire.fprintf(pipewire.stdout, "capturing rate:%d channels:%d\n", data.format.info.raw.rate, data.format.info.raw.channels);
+                }
+            }
+        }
+    }
+}
+
+const stream_events = pipewire.pw_stream_events{
+    .version = pipewire.PW_VERSION_STREAM_EVENTS,
+    .param_changed = on_stream_param_changed,
+    .process = on_process,
+};
+
+export fn do_quit(userdata: ?*anyopaque, signalnumber: c_int) void {
+    const data: *data_struct = @ptrCast(@alignCast(userdata));
+    _ = pipewire.pw_main_loop_quit(data.loop);
+    _ = signalnumber;
+}
 
 pub fn main() !void {
-    // Prints to stderr (it's a shortcut based on `std.io.getStdErr()`)
+    var data: data_struct = undefined;
-    std.debug.print("All your {s} are belong to us.\n", .{"codebase"});
+    var params: [1][*c]const pipewire.spa_pod = undefined;
-
+    var buffer: [1024]u8 = undefined;
-    // stdout is for the actual output of your application, for example if you
+    var props: *pipewire.pw_properties = undefined;
-    // are implementing gzip, then only the compressed bytes should be sent to
+    var b: pipewire.spa_pod_builder = pipewire.spa_pod_builder{
-    // stdout, not any debugging messages.
+        .data = &buffer,
-    const stdout_file = std.io.getStdOut().writer();
+        .size = @sizeOf([1024]u8),
-    var bw = std.io.bufferedWriter(stdout_file);
+        ._padding = 0,
-    const stdout = bw.writer();
+        .state = .{
-
+            .flags = 0,
-    try stdout.print("Run `zig build test` to run the tests.\n", .{});
+            .offset = 0,
-
+            .frame = null,
-    try bw.flush(); // Don't forget to flush!
+        },
-}
+        .callbacks = .{
-
+            .data = null,
-test "simple test" {
+            .funcs = null,
-    var list = std.ArrayList(i32).init(std.testing.allocator);
+        },
-    defer list.deinit(); // Try commenting this out and see if zig detects the memory leak!
-    try list.append(42);
-    try std.testing.expectEqual(@as(i32, 42), list.pop());
-}
-
-test "use other module" {
-    try std.testing.expectEqual(@as(i32, 150), lib.add(100, 50));
-}
-
-test "fuzz example" {
-    const Context = struct {
-        fn testOne(context: @This(), input: []const u8) anyerror!void {
-            _ = context;
-            // Try passing `--fuzz` to `zig build test` and see if it manages to fail this test case!
-            try std.testing.expect(!std.mem.eql(u8, "canyoufindme", input));
-        }
     };
-    try std.testing.fuzz(Context{}, Context.testOne, .{});
+
+    const argv = std.os.argv;
+    var c_ptr: [*c][*c]u8 = @ptrCast(argv.ptr);
+    var argc: c_int = @intCast(std.os.argv.len);
+
+    pipewire.pw_init(&argc, &c_ptr);
+
+    std.log.info(
+        \\ Compiled with libpipewire {s}
+        \\ Linked with libpipewire {s},
+    , .{
+        pipewire.pw_get_headers_version(),
+        pipewire.pw_get_library_version(),
+    });
+
+    data.loop = pipewire.pw_main_loop_new(null);
+
+    _ = pipewire.pw_loop_add_signal(pipewire.pw_main_loop_get_loop(data.loop), pipewire.SIGINT, do_quit, &data);
+    _ = pipewire.pw_loop_add_signal(pipewire.pw_main_loop_get_loop(data.loop), pipewire.SIGTERM, do_quit, &data);
+
+    props = pipewire.pw_properties_new(
+        pipewire.PW_KEY_MEDIA_TYPE,
+        "Audio",
+        pipewire.PW_KEY_MEDIA_CATEGORY,
+        "Capture",
+        pipewire.PW_KEY_MEDIA_ROLE,
+        "Music",
+        @as(?*anyopaque, @ptrFromInt(0)),
+    );
+
+    if (argc > 1) _ = pipewire.pw_properties_set(props, pipewire.PW_KEY_TARGET_OBJECT, argv[1]);
+
+    data.stream = pipewire.pw_stream_new_simple(
+        pipewire.pw_main_loop_get_loop(data.loop),
+        "audio-capture",
+        props,
+        &stream_events,
+        &data,
+    );
+
+    params[0] = pipewire.spa_format_audio_raw_build(
+        &b,
+        pipewire.SPA_PARAM_EnumFormat,
+        &pipewire.spa_audio_info_raw{ .format = pipewire.SPA_AUDIO_FORMAT_F32 },
+    );
+
+    _ = pipewire.pw_stream_connect(data.stream, pipewire.PW_DIRECTION_INPUT, pipewire.PW_ID_ANY, pipewire.PW_STREAM_FLAG_AUTOCONNECT | pipewire.PW_STREAM_FLAG_MAP_BUFFERS | pipewire.PW_STREAM_FLAG_RT_PROCESS, params[0..].ptr, @as(u32, 1));
+
+    _ = pipewire.pw_main_loop_run(data.loop);
+
+    pipewire.pw_stream_destroy(data.stream);
+    pipewire.pw_main_loop_destroy(data.loop);
+    pipewire.pw_deinit();
 }
 
+extern "c" fn pw_log_warn(...) void;
+
 const std = @import("std");
 
-/// This imports the separate module containing `root.zig`. Take a look in `build.zig` for details.
+const pipewire = @cImport({
-const lib = @import("zig_lib");
+    @cInclude("pipewire/pipewire.h");
+    @cInclude("spa/param/audio/format-utils.h");
+});