startiing to clean up c api

Should map directly to the zig struct instead of mallocing

build.zig

@@ -1,121 +1,88 @@
 const std = @import("std");
+const Step = std.Build.Step;
 
-// Although this function looks imperative, it does not perform the build
-// directly and instead it mutates the build graph (`b`) that will be then
-// 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).
+// 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 allow the person running `zig build` to choose
+    // 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(.{});
-    // It's also possible to define more custom flags to toggle optional features
-    // of this build script using `b.option()`. All defined flags (including
-    // target and optimize options) will be listed when running `zig build --help`
-    // in this directory.
 
-    // This creates a module, which represents a collection of source files alongside
-    // some compilation options, such as optimization mode and linked system libraries.
-    // Zig modules are the preferred way of making Zig code available to consumers.
-    // addModule defines a module that we intend to make available for importing
-    // 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("zaprus", .{
-        // 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.
+    const lib_mod = b.createModule(.{
         .root_source_file = b.path("src/root.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,
-    });
-
-    mod.addImport("network", b.dependency("network", .{}).module("network"));
-    mod.addImport("gatorcat", b.dependency("gatorcat", .{}).module("gatorcat"));
-
-    // Here we define an executable. An executable needs to have a root module
-    // which needs to expose a `main` function. While we could add a main function
-    // to the module defined above, it's sometimes preferable to split business
-    // business logic and the CLI into two separate modules.
-    //
-    // If your goal is to create a Zig library for others to use, consider if
-    // it might benefit from also exposing a CLI tool. A parser library for a
-    // data serialization format could also bundle a CLI syntax checker, for example.
-    //
-    // If instead your goal is to create an executable, consider if users might
-    // be interested in also being able to embed the core functionality of your
-    // program in their own executable in order to avoid the overhead involved in
-    // subprocessing your CLI tool.
-    //
-    // If neither case applies to you, feel free to delete the declaration you
-    // don't need and to put everything under a single module.
-    const exe = b.addExecutable(.{
-        .name = "zaprus",
-        .root_module = b.createModule(.{
-            // b.createModule defines a new module just like b.addModule but,
-            // unlike b.addModule, it does not expose the module to consumers of
-            // this package, which is why in this case we don't have to give it a name.
-            .root_source_file = b.path("src/main.zig"),
-            // Target and optimization levels must be explicitly wired in when
-            // defining an executable or library (in the root module), and you
-            // can also hardcode a specific target for an executable or library
-            // definition if desireable (e.g. firmware for embedded devices).
         .target = target,
         .optimize = optimize,
-            // List of modules available for import in source files part of the
-            // root module.
-            .imports = &.{
-                // Here "zaprus" is the name you will use in your source code to
-                // import this module (e.g. `@import("zaprus")`). The name is
-                // repeated because you are allowed to rename your imports, which
-                // can be extremely useful in case of collisions (which can happen
-                // importing modules from different packages).
-                .{ .name = "zaprus", .module = mod },
-                .{ .name = "clap", .module = b.dependency("clap", .{}).module("clap") },
-            },
-        }),
+    });
+
+    // 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
+        // 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/main.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+
+    lib_mod.addImport("network", b.dependency("network", .{}).module("network"));
+
+    exe_mod.addImport("zaprus", lib_mod);
+    exe_mod.addImport("clap", b.dependency("clap", .{}).module("clap"));
+
+    const static_lib = b.addLibrary(.{
+        .linkage = .static,
+        .name = "zaprus",
+        .root_module = lib_mod,
+    });
+    static_lib.addIncludePath(.{ .cwd_relative = "include" });
+    static_lib.linkLibC();
+
+    b.installArtifact(static_lib);
+
+    const dynamic_lib = b.addLibrary(.{
+        .linkage = .dynamic,
+        .name = "zaprus",
+        .root_module = lib_mod,
+    });
+    dynamic_lib.addIncludePath(.{ .cwd_relative = "include" });
+    dynamic_lib.linkLibC();
+
+    b.installArtifact(dynamic_lib);
+
+    // C Headers
+    const c_header = b.addInstallHeaderFile(b.path("include/zaprus.h"), "zaprus.h");
+    b.getInstallStep().dependOn(&c_header.step);
+
+    // This creates another `std.Build.Step.Compile`, but this one builds an executable
+    // rather than a static library.
+    const exe = b.addExecutable(.{
+        .name = "zaprus",
+        .root_module = exe_mod,
     });
 
     // This declares intent for the executable to be installed into the
-    // install prefix when running `zig build` (i.e. when executing the default
-    // step). By default the install prefix is `zig-out/` but can be overridden
-    // by passing `--prefix` or `-p`.
+    // standard location when the user invokes the "install" step (the default
+    // step when running `zig build`).
     b.installArtifact(exe);
-    b.installArtifact(b.addLibrary(.{
-        .linkage = .static,
-        .name = "zaprus",
-        .root_module = mod,
-    }));
 
-    // This creates a top level step. Top level steps have a name and can be
-    // invoked by name when running `zig build` (e.g. `zig build run`).
-    // This will evaluate the `run` step rather than the default step.
-    // For a top level step to actually do something, it must depend on other
-    // steps (e.g. a Run step, as we will see in a moment).
-    const run_step = b.step("run", "Run the app");
-
-    // This creates a RunArtifact step in the build graph. A RunArtifact step
-    // invokes an executable compiled by Zig. Steps will only be executed by the
-    // runner if invoked directly by the user (in the case of top level steps)
-    // or if another step depends on it, so it's up to you to define when and
-    // how this Run step will be executed. In our case we want to run it when
-    // the user runs `zig build run`, so we create a dependency link.
+    // This *creates* a Run step in the build graph, to be executed when another
+    // step is evaluated that depends on it. The next line below will establish
+    // such a dependency.
     const run_cmd = b.addRunArtifact(exe);
-    run_step.dependOn(&run_cmd.step);
 
-    // By making the run step depend on the default step, it will be run from the
+    // By making the run step depend on the install step, it will be run from the
     // installation directory rather than directly from within the cache directory.
+    // This is not necessary, however, if the application depends on other installed
+    // files, this ensures they will be present and in the expected location.
     run_cmd.step.dependOn(b.getInstallStep());
 
     // This allows the user to pass arguments to the application in the build
@@ -124,42 +91,21 @@ pub fn build(b: *std.Build) void {
         run_cmd.addArgs(args);
     }
 
-    // Creates an executable that will run `test` blocks from the provided module.
-    // Here `mod` needs to define a target, which is why earlier we made sure to
-    // set the releative field.
-    const mod_tests = b.addTest(.{
-        .root_module = mod,
+    // This creates a build step. It will be visible in the `zig build --help` menu,
+    // and can be selected like this: `zig build run`
+    // This will evaluate the `run` step rather than the default, which is "install".
+    const run_step = b.step("run", "Run the app");
+    run_step.dependOn(&run_cmd.step);
+
+    const exe_unit_tests = b.addTest(.{
+        .root_module = exe_mod,
     });
 
-    // A run step that will run the test executable.
-    const run_mod_tests = b.addRunArtifact(mod_tests);
+    const run_exe_unit_tests = b.addRunArtifact(exe_unit_tests);
 
-    // Creates an executable that will run `test` blocks from the executable's
-    // root module. Note that test executables only test one module at a time,
-    // hence why we have to create two separate ones.
-    const exe_tests = b.addTest(.{
-        .root_module = exe.root_module,
-    });
-
-    // A run step that will run the second test executable.
-    const run_exe_tests = b.addRunArtifact(exe_tests);
-
-    // A top level step for running all tests. dependOn can be called multiple
-    // times and since the two run steps do not depend on one another, this will
-    // make the two of them run in parallel.
-    const test_step = b.step("test", "Run tests");
-    test_step.dependOn(&run_mod_tests.step);
-    test_step.dependOn(&run_exe_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.
+    // Similar to creating the run step earlier, this exposes a `test` step to
+    // 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_exe_unit_tests.step);
 }

build.zig.zon

@@ -37,16 +37,12 @@
     // internet connectivity.
     .dependencies = .{
         .network = .{
-            .url = "git+https://github.com/ikskuh/zig-network#7947237eec317d9458897f82089f343a05450c2b",
-            .hash = "network-0.1.0-Pm-Agl8xAQBmkwohveGOfTk4zQnuqDs0Ptfbms4KP5Ce",
+            .url = "https://github.com/ikskuh/zig-network/archive/c76240d2240711a3dcbf1c0fb461d5d1f18be79a.zip",
+            .hash = "network-0.1.0-AAAAAOwlAQAQ6zKPUrsibdpGisxld9ftUKGdMvcCSpaj",
         },
         .clap = .{
-            .url = "git+https://github.com/Hejsil/zig-clap#9cfa61596cd44ef7be35f8d2e108d2025e09868e",
-            .hash = "clap-0.10.0-oBajB_TnAQB0l5UdW9WYhhJDEswbedvwFOzzZwGknYeR",
-        },
-        .gatorcat = .{
-            .url = "git+https://github.com/jeffective/gatorcat#db73d0f7780331d82e785e85773d1afaf154c2e6",
-            .hash = "gatorcat-0.3.11-WcrpTQn0BwArrCFVHy9FPBIPDJQqPrFdJlhiyH7Ng5x4",
+            .url = "git+https://github.com/Hejsil/zig-clap?ref=0.10.0#e47028deaefc2fb396d3d9e9f7bd776ae0b2a43a",
+            .hash = "clap-0.10.0-oBajB434AQBDh-Ei3YtoKIRxZacVPF1iSwp3IX_ZB8f0",
         },
     },
     .paths = .{

include/zaprus.h

@@ -0,0 +1,15 @@
+// client
+
+#include<stdint.h>
+#include<stdlib.h>
+
+int zaprus_init(void);
+
+int zaprus_deinit(void);
+
+int zaprus_send_relay(const char* payload, size_t len, char dest[4]);
+
+int zaprus_send_initial_connection(const char* payload, size_t len, uint16_t initial_port);
+
+void* zaprus_connect(const char* payload, size_t len);
+

src/Client.zig

@@ -1,84 +1,22 @@
-const base64Enc = std.base64.Base64Encoder.init(std.base64.standard_alphabet_chars, '=');
-const base64Dec = std.base64.Base64Decoder.init(std.base64.standard_alphabet_chars, '=');
+var rand: ?Random = null;
 
-rand: Random,
-writer: *std.Io.Writer,
-
-const Self = @This();
-
-const max_message_size = 2048;
-
-pub fn init(writer: *std.Io.Writer) !Self {
+pub fn init() !void {
     var prng = Random.DefaultPrng.init(blk: {
         var seed: u64 = undefined;
         try posix.getrandom(mem.asBytes(&seed));
         break :blk seed;
     });
-    const rand = prng.random();
-
-    return .{
-        .rand = rand,
-        .writer = writer,
-    };
+    rand = prng.random();
+    try network.init();
 }
 
-pub fn deinit(self: *Self) void {
-    self.writer.flush() catch {};
+pub fn deinit() void {
+    network.deinit();
 }
 
-/// Used for relay messages and connection handshake.
-/// Assumes Client .init has been called.
-fn broadcastInitialInterestMessage(self: *Self, msg_bytes: []align(@alignOf(SaprusMessage)) u8) !void {
-    var packet_bytes: [max_message_size]u8 = comptime blk: {
-        var b: [max_message_size]u8 = @splat(0);
-
-        // Destination MAC addr to FF:FF:FF:FF:FF:FF
-        for (0..6) |i| {
-            b[i] = 0xff;
-        }
-
-        // Set Ethernet type to IPv4
-        b[0x0c] = 0x08;
-        b[0x0d] = 0x00;
-
-        // Set IPv4 version to 4
-        b[0x0e] = 0x45;
-
-        // Destination broadcast
-        for (0x1e..0x22) |i| {
-            b[i] = 0xff;
-        }
-
-        // Set TTL
-        b[0x16] = 0x40;
-
-        // Set IPv4 protocol to UDP
-        b[0x17] = 0x11;
-
-        // Set interest filter value to 8888.
-        b[0x24] = 0x22;
-        b[0x25] = 0xb8;
-        break :blk b;
-    };
-    var msg: *SaprusMessage = try .bytesAsValue(msg_bytes);
-    try msg.networkFromNativeEndian();
-    defer msg.nativeFromNetworkEndian() catch unreachable;
-
-    // The byte position within the packet that the saprus message starts at.
-    const saprus_start_byte = 42;
-    @memcpy(packet_bytes[saprus_start_byte .. saprus_start_byte + msg_bytes.len], msg_bytes);
-
-    const writer = self.writer;
-    _ = try writer.write(packet_bytes[0 .. saprus_start_byte + msg_bytes.len]);
-    try writer.flush();
-}
-
-// fn broadcastSaprusMessage(msg_bytes: []align(@alignOf(SaprusMessage)) u8) !void {}
-
-fn broadcastSaprusMessage(msg_bytes: []align(@alignOf(SaprusMessage)) u8, udp_port: u16) !void {
-    const msg: *SaprusMessage = try .bytesAsValue(msg_bytes);
-    try msg.networkFromNativeEndian();
-    defer msg.nativeFromNetworkEndian() catch unreachable;
+fn broadcastSaprusMessage(msg: SaprusMessage, udp_port: u16, allocator: Allocator) !void {
+    const msg_bytes = try msg.toBytes(allocator);
+    defer allocator.free(msg_bytes);
 
     var sock = try network.Socket.create(.ipv4, .udp);
     defer sock.close();
@@ -98,57 +36,54 @@ fn broadcastSaprusMessage(msg_bytes: []align(@alignOf(SaprusMessage)) u8, udp_po
 
     try sock.bind(bind_addr);
 
-    std.debug.print("{x}\n", .{msg_bytes});
-
     _ = try sock.sendTo(dest_addr, msg_bytes);
 }
 
-pub fn sendRelay(self: *Self, payload: []const u8, dest: [4]u8) !void {
-    var buf: [max_message_size]u8 align(@alignOf(SaprusMessage)) = undefined;
-    const msg_bytes = buf[0..try SaprusMessage.calcSize(
-        .relay,
-        base64Enc.calcSize(payload.len),
-    )];
-    const msg: *SaprusMessage = .init(.relay, msg_bytes);
+pub fn sendRelay(payload: []const u8, dest: [4]u8, allocator: Allocator) !void {
+    const msg = SaprusMessage{
+        .relay = .{
+            .header = .{ .dest = dest },
+            .payload = payload,
+        },
+    };
 
-    const relay = (try msg.getSaprusTypePayload()).relay;
-    relay.dest = dest;
-    _ = base64Enc.encode(relay.getPayload(), payload);
-
-    try self.broadcastInitialInterestMessage(msg_bytes);
+    try broadcastSaprusMessage(msg, 8888, allocator);
 }
 
-fn randomPort(self: Self) u16 {
-    return self.rand.intRangeAtMost(u16, 1024, 65000);
+fn randomPort() u16 {
+    var p: u16 = 0;
+    if (rand) |r| {
+        p = r.intRangeAtMost(u16, 1024, 65000);
+    } else unreachable;
+
+    return p;
 }
 
-pub fn sendInitialConnection(
-    self: Self,
-    payload: []const u8,
-    output_bytes: []align(@alignOf(SaprusMessage)) u8,
-    initial_port: u16,
-) !*SaprusMessage {
-    const dest_port = self.randomPort();
-    const msg_bytes = output_bytes[0..try SaprusMessage.calcSize(
-        .connection,
-        base64Enc.calcSize(payload.len),
-    )];
-    const msg: *SaprusMessage = .init(.connection, msg_bytes);
+pub fn sendInitialConnection(payload: []const u8, initial_port: u16, allocator: Allocator) !SaprusMessage {
+    const dest_port = randomPort();
+    const msg = SaprusMessage{
+        .connection = .{
+            .header = .{
+                .src_port = initial_port,
+                .dest_port = dest_port,
+            },
+            .payload = payload,
+        },
+    };
 
-    const connection = (try msg.getSaprusTypePayload()).connection;
-    connection.src_port = initial_port;
-    connection.dest_port = dest_port;
-    _ = base64Enc.encode(connection.getPayload(), payload);
-
-    try broadcastSaprusMessage(msg_bytes, 8888);
+    try broadcastSaprusMessage(msg, 8888, allocator);
 
     return msg;
 }
 
-pub fn connect(self: Self, payload: []const u8) !?SaprusConnection {
-    const initial_port = self.randomPort();
+pub fn connect(payload: []const u8, allocator: Allocator) !SaprusMessage {
+    var initial_port: u16 = 0;
+    if (rand) |r| {
+        initial_port = r.intRangeAtMost(u16, 1024, 65000);
+    } else unreachable;
 
-    var initial_conn_res: ?*SaprusMessage = null;
+    var initial_conn_res: ?SaprusMessage = null;
+    errdefer if (initial_conn_res) |c| c.deinit(allocator);
 
     var sock = try network.Socket.create(.ipv4, .udp);
     defer sock.close();
@@ -163,26 +98,21 @@ pub fn connect(self: Self, payload: []const u8) !?SaprusConnection {
     try sock.setReadTimeout(1 * std.time.us_per_s);
     try sock.bind(bind_addr);
 
-    var sent_msg_bytes: [max_message_size]u8 align(@alignOf(SaprusMessage)) = undefined;
-    const msg = try self.sendInitialConnection(payload, &sent_msg_bytes, initial_port);
+    const msg = try sendInitialConnection(payload, initial_port, allocator);
 
-    var response_buf: [max_message_size]u8 align(@alignOf(SaprusMessage)) = undefined;
+    var response_buf: [4096]u8 = undefined;
     _ = try sock.receive(&response_buf); // Ignore message that I sent.
     const len = try sock.receive(&response_buf);
 
-    initial_conn_res = try .networkBytesAsValue(response_buf[0..len]);
+    initial_conn_res = try SaprusMessage.fromBytes(response_buf[0..len], allocator);
 
     // Complete handshake after awaiting response
-    try broadcastSaprusMessage(msg.asBytes(), self.randomPort());
+    try broadcastSaprusMessage(msg, randomPort(), allocator);
 
-    if (false) {
     return initial_conn_res.?;
 }
-    return null;
-}
 
 const SaprusMessage = @import("message.zig").Message;
-const SaprusConnection = @import("Connection.zig");
 
 const std = @import("std");
 const Random = std.Random;
@@ -190,3 +120,5 @@ const posix = std.posix;
 const mem = std.mem;
 
 const network = @import("network");
+
+const Allocator = mem.Allocator;

src/RawSocketWriter.zig

@@ -1,45 +0,0 @@
-const std = @import("std");
-const gcat = @import("gatorcat");
-const Writer = @This();
-const assert = std.debug.assert;
-
-interface: std.Io.Writer,
-socket: gcat.nic.RawSocket,
-alloc: std.mem.Allocator,
-
-fn drain(io_w: *std.Io.Writer, data: []const []const u8, splat: usize) std.Io.Writer.Error!usize {
-    const w: *Writer = @alignCast(@fieldParentPtr("interface", io_w));
-    const buffered = io_w.buffered();
-    var res: usize = 0;
-    if (buffered.len > 0) {
-        w.socket.linkLayer().send(buffered) catch return error.WriteFailed;
-        _ = io_w.consumeAll();
-    }
-
-    for (data[0 .. data.len - 1]) |d| {
-        w.socket.linkLayer().send(d) catch return error.WriteFailed;
-        res += d.len;
-    }
-
-    if (splat > 0 and data[data.len - 1].len > 0) {
-        var splatBuffer: std.ArrayList(u8) = .empty;
-        defer splatBuffer.deinit(w.alloc);
-        for (0..splat) |_| {
-            splatBuffer.appendSlice(w.alloc, data[data.len - 1]) catch return error.WriteFailed;
-        }
-        w.socket.linkLayer().send(splatBuffer.items) catch return error.WriteFailed;
-    }
-
-    return res;
-}
-
-pub fn init(interface_name: [:0]const u8, buffer: []u8, alloc: std.mem.Allocator) !Writer {
-    return .{
-        .interface = .{
-            .vtable = &.{ .drain = drain },
-            .buffer = buffer,
-        },
-        .socket = try .init(interface_name),
-        .alloc = alloc,
-    };
-}

src/c_api.zig

@@ -0,0 +1,32 @@
+// client
+export fn zaprus_init() c_int {
+    SaprusClient.init() catch return 1;
+    return 0;
+}
+
+export fn zaprus_deinit() c_int {
+    SaprusClient.deinit();
+    return 0;
+}
+
+export fn zaprus_send_relay(payload: [*]const u8, len: usize, dest: [*]u8) c_int {
+    SaprusClient.sendRelay(payload[0..len], dest[0..4].*, allocator) catch return 1;
+    return 0;
+}
+
+export fn zaprus_connect(payload: [*]const u8, len: usize, output: *SaprusConnection) c_int {
+    output.* = (SaprusClient.connect(payload[0..len], allocator) catch return 1).?;
+    return 0;
+}
+
+const std = @import("std");
+
+const zaprus = @import("./root.zig");
+const SaprusClient = zaprus.Client;
+const SaprusConnection = zaprus.Connection;
+
+const allocator = std.heap.c_allocator;
+
+test {
+    std.testing.refAllDeclsRecursively(@This());
+}

src/main.zig

@@ -37,37 +37,42 @@ pub fn main() !void {
         .allocator = gpa,
     }) catch |err| {
         // Report useful error and exit.
-        try diag.reportToFile(.stderr(), err);
+        diag.report(std.io.getStdErr().writer(), err) catch {};
         return err;
     };
     defer res.deinit();
 
+    try SaprusClient.init();
+    defer SaprusClient.deinit();
+
     if (res.args.help != 0) {
-        return clap.helpToFile(.stderr(), clap.Help, &params, .{});
+        return clap.help(std.io.getStdErr().writer(), clap.Help, &params, .{});
     }
 
-    var sock_buffer: [2048]u8 = undefined;
-    var rawSocketWriter: RawSocketWriter = try .init("enp7s0", &sock_buffer, gpa); // /proc/net/dev
-    var client = try SaprusClient.init(&rawSocketWriter.interface);
-    defer client.deinit();
-
     if (res.args.relay) |r| {
-        const dest = parseDest(res.args.dest);
-        try client.sendRelay(
+        const dest = parseDest(res.args.dest) catch .{ 70, 70, 70, 70 };
+        try SaprusClient.sendRelay(
             if (r.len > 0) r else "Hello darkness my old friend",
             dest,
+            gpa,
         );
         // std.debug.print("Sent: {s}\n", .{r});
         return;
     } else if (res.args.connect) |c| {
-        _ = client.connect(if (c.len > 0) c else "Hello darkness my old friend") catch |err| switch (err) {
+        const conn_res: ?SaprusMessage = SaprusClient.connect(if (c.len > 0) c else "Hello darkness my old friend", gpa) catch |err| switch (err) {
             error.WouldBlock => null,
             else => return err,
         };
+        defer if (conn_res) |r| r.deinit(gpa);
+        if (conn_res) |r| {
+            std.debug.print("{s}\n", .{r.connection.payload});
+        } else {
+            std.debug.print("No response from connection request\n", .{});
+        }
         return;
     }
 
-    return clap.helpToFile(.stderr(), clap.Help, &params, .{});
+    return clap.help(std.io.getStdErr().writer(), clap.Help, &params, .{});
 }
 
 fn parseDest(in: ?[]const u8) [4]u8 {
@@ -81,7 +86,7 @@ fn parseDest(in: ?[]const u8) [4]u8 {
         const addr = std.net.Ip4Address.parse(dest, 0) catch return "FAIL".*;
         return @bitCast(addr.sa.addr);
     }
-    return "zap\x00".*;
+    return "zap".*;
 }
 
 const builtin = @import("builtin");
@@ -92,6 +97,5 @@ const ArrayList = std.ArrayList;
 const zaprus = @import("zaprus");
 const SaprusClient = zaprus.Client;
 const SaprusMessage = zaprus.Message;
-const RawSocketWriter = zaprus.RawSocketWriter;
 
 const clap = @import("clap");

src/message.zig

@@ -1,3 +1,6 @@
+const base64Enc = std.base64.Base64Encoder.init(std.base64.standard_alphabet_chars, '=');
+const base64Dec = std.base64.Base64Decoder.init(std.base64.standard_alphabet_chars, '=');
+
 /// Type tag for Message union.
 /// This is the first value in the actual packet sent over the network.
 pub const PacketType = enum(u16) {
@@ -20,255 +23,155 @@ pub const ConnectionOptions = packed struct(u8) {
     opt8: bool = false,
 };
 
-pub const MessageTypeError = error{
+pub const Error = error{
     NotImplementedSaprusType,
     UnknownSaprusType,
 };
-pub const MessageParseError = MessageTypeError || error{
-    InvalidMessage,
-};
 
-// ZERO COPY STUFF
-// &payload could be a void value that is treated as a pointer to a [*]u8
 /// All Saprus messages
-pub const Message = packed struct {
-    const Relay = packed struct {
+pub const Message = union(PacketType) {
+    pub const Relay = struct {
+        pub const Header = packed struct {
             dest: @Vector(4, u8),
-        payload: void,
-
-        pub fn getPayload(self: *align(1) Relay) []u8 {
-            const len: *u16 = @ptrFromInt(@intFromPtr(self) - @sizeOf(u16));
-            return @as([*]u8, @ptrCast(&self.payload))[0 .. len.* - @bitSizeOf(Relay) / 8];
-        }
         };
-    const Connection = packed struct {
+        header: Header,
+        payload: []const u8,
+    };
+    pub const Connection = struct {
+        pub const Header = packed struct {
             src_port: u16, // random number > 1024
             dest_port: u16, // random number > 1024
             seq_num: u32 = 0,
             msg_id: u32 = 0,
             reserved: u8 = 0,
             options: ConnectionOptions = .{},
-        payload: void,
-
-        pub fn getPayload(self: *align(1) Connection) []u8 {
-            const len: *u16 = @ptrFromInt(@intFromPtr(self) - @sizeOf(u16));
-            return @as([*]u8, @ptrCast(&self.payload))[0 .. len.* - @bitSizeOf(Connection) / 8];
-        }
-
-        fn nativeFromNetworkEndian(self: *align(1) Connection) void {
-            self.src_port = bigToNative(@TypeOf(self.src_port), self.src_port);
-            self.dest_port = bigToNative(@TypeOf(self.dest_port), self.dest_port);
-            self.seq_num = bigToNative(@TypeOf(self.seq_num), self.seq_num);
-            self.msg_id = bigToNative(@TypeOf(self.msg_id), self.msg_id);
-        }
-
-        fn networkFromNativeEndian(self: *align(1) Connection) void {
-            self.src_port = nativeToBig(@TypeOf(self.src_port), self.src_port);
-            self.dest_port = nativeToBig(@TypeOf(self.dest_port), self.dest_port);
-            self.seq_num = nativeToBig(@TypeOf(self.seq_num), self.seq_num);
-            self.msg_id = nativeToBig(@TypeOf(self.msg_id), self.msg_id);
-        }
         };
-
-    const Self = @This();
-    const SelfBytes = []align(@alignOf(Self)) u8;
-
-    type: PacketType,
-    length: u16,
-    bytes: void = {},
-
-    /// Takes a byte slice, and returns a Message struct backed by the slice.
-    /// This properly initializes the top level headers within the slice.
-    /// This is used for creating new messages. For reading messages from the network,
-    /// see: networkBytesAsValue.
-    pub fn init(@"type": PacketType, bytes: []align(@alignOf(Self)) u8) *Self {
-        std.debug.assert(bytes.len >= @sizeOf(Self));
-        const res: *Self = @ptrCast(bytes.ptr);
-        res.type = @"type";
-        res.length = @intCast(bytes.len - @sizeOf(Self));
-        return res;
-    }
-
-    /// Compute the number of bytes required to store a given payload size for a given message type.
-    pub fn calcSize(comptime @"type": PacketType, payload_len: usize) MessageTypeError!u16 {
-        const header_size = @bitSizeOf(switch (@"type") {
-            .relay => Relay,
-            .connection => Connection,
-            .file_transfer => return MessageTypeError.NotImplementedSaprusType,
-            else => return MessageTypeError.UnknownSaprusType,
-        }) / 8;
-        return @intCast(payload_len + @sizeOf(Self) + header_size);
-    }
-
-    fn getRelay(self: *Self) *align(1) Relay {
-        return std.mem.bytesAsValue(Relay, &self.bytes);
-    }
-    fn getConnection(self: *Self) *align(1) Connection {
-        return std.mem.bytesAsValue(Connection, &self.bytes);
-    }
-
-    /// Access the message Saprus payload.
-    pub fn getSaprusTypePayload(self: *Self) MessageTypeError!(union(PacketType) {
-        relay: *align(1) Relay,
-        file_transfer: void,
-        connection: *align(1) Connection,
-    }) {
-        return switch (self.type) {
-            .relay => .{ .relay = self.getRelay() },
-            .connection => .{ .connection = self.getConnection() },
-            .file_transfer => MessageTypeError.NotImplementedSaprusType,
-            else => MessageTypeError.UnknownSaprusType,
+        header: Header,
+        payload: []const u8,
     };
-    }
+    relay: Relay,
+    file_transfer: void, // unimplemented
+    connection: Connection,
 
-    /// Convert the message to native endianness from network endianness in-place.
-    pub fn nativeFromNetworkEndian(self: *Self) MessageTypeError!void {
-        self.type = @enumFromInt(bigToNative(
-            @typeInfo(@TypeOf(self.type)).@"enum".tag_type,
-            @intFromEnum(self.type),
-        ));
-        self.length = bigToNative(@TypeOf(self.length), self.length);
-        errdefer {
-            // If the payload specific headers fail, revert the top level header values
-            self.type = @enumFromInt(nativeToBig(
-                @typeInfo(@TypeOf(self.type)).@"enum".tag_type,
-                @intFromEnum(self.type),
-            ));
-            self.length = nativeToBig(@TypeOf(self.length), self.length);
-        }
-        switch (try self.getSaprusTypePayload()) {
-            .relay => {},
-            .connection => |*con| con.*.nativeFromNetworkEndian(),
-            // We know other values are unreachable,
-            // because they would have returned an error from the switch condition.
+    /// Should be called for any Message that was declared using a function that you pass an allocator to.
+    pub fn deinit(self: Message, allocator: Allocator) void {
+        switch (self) {
+            .relay => |r| allocator.free(r.payload),
+            .connection => |c| allocator.free(c.payload),
             else => unreachable,
         }
     }
 
-    /// Convert the message to network endianness from native endianness in-place.
-    pub fn networkFromNativeEndian(self: *Self) MessageTypeError!void {
-        try switch (try self.getSaprusTypePayload()) {
-            .relay => {},
-            .connection => |*con| con.*.networkFromNativeEndian(),
-            .file_transfer => MessageTypeError.NotImplementedSaprusType,
-            else => MessageTypeError.UnknownSaprusType,
-        };
-        self.type = @enumFromInt(nativeToBig(
-            @typeInfo(@TypeOf(self.type)).@"enum".tag_type,
-            @intFromEnum(self.type),
-        ));
-        self.length = nativeToBig(@TypeOf(self.length), self.length);
+    fn toBytesAux(
+        header: anytype,
+        payload: []const u8,
+        buf: *std.ArrayList(u8),
+        allocator: Allocator,
+    ) !void {
+        const Header = @TypeOf(header);
+        // Create a growable string to store the base64 bytes in.
+        // Doing this first so I can use the length of the encoded bytes for the length field.
+        var payload_list = std.ArrayList(u8).init(allocator);
+        defer payload_list.deinit();
+        const buf_w = payload_list.writer();
+
+        // Write the payload bytes as base64 to the growable string.
+        try base64Enc.encodeWriter(buf_w, payload);
+
+        // At this point, payload_list contains the base64 encoded payload.
+
+        // Add the payload length to the output buf.
+        try buf.*.appendSlice(
+            asBytes(&nativeToBig(u16, @intCast(payload_list.items.len + @bitSizeOf(Header) / 8))),
+        );
+
+        // Add the header bytes to the output buf.
+        var header_buf: [@sizeOf(Header)]u8 = undefined;
+        var header_buf_stream = std.io.fixedBufferStream(&header_buf);
+        try header_buf_stream.writer().writeStructEndian(header, .big);
+        // Add the exact number of bits in the header without padding.
+        try buf.*.appendSlice(header_buf[0 .. @bitSizeOf(Header) / 8]);
+
+        try buf.*.appendSlice(payload_list.items);
     }
 
-    /// Convert network endian bytes to a native endian value in-place.
-    pub fn networkBytesAsValue(bytes: SelfBytes) MessageParseError!*Self {
-        const res = std.mem.bytesAsValue(Self, bytes);
-        try res.nativeFromNetworkEndian();
-        return .bytesAsValue(bytes);
+    /// Caller is responsible for freeing the returned bytes.
+    pub fn toBytes(self: Message, allocator: Allocator) ![]u8 {
+        // Create a growable list of bytes to store the output in.
+        var buf = std.ArrayList(u8).init(allocator);
+        errdefer buf.deinit();
+
+        // Start with writing the message type, which is the first 16 bits of every Saprus message.
+        try buf.appendSlice(asBytes(&nativeToBig(u16, @intFromEnum(self))));
+
+        // Write the proper header and payload for the given packet type.
+        switch (self) {
+            .relay => |r| try toBytesAux(r.header, r.payload, &buf, allocator),
+            .connection => |c| try toBytesAux(c.header, c.payload, &buf, allocator),
+            .file_transfer => return Error.NotImplementedSaprusType,
         }
 
-    /// Create a structured view of the bytes without initializing the length or type,
-    /// and without converting the endianness.
-    pub fn bytesAsValue(bytes: SelfBytes) MessageParseError!*Self {
-        const res = std.mem.bytesAsValue(Self, bytes);
-        return switch (res.type) {
-            .relay, .connection => if (bytes.len == res.length + @sizeOf(Self))
-                res
-            else
-                MessageParseError.InvalidMessage,
-            .file_transfer => MessageParseError.NotImplementedSaprusType,
-            else => MessageParseError.UnknownSaprusType,
-        };
+        // Collect the growable list as a slice and return it.
+        return buf.toOwnedSlice();
     }
 
-    /// Deprecated.
-    /// If I need the bytes, I should just pass around the slice that is backing this to begin with.
-    pub fn asBytes(self: *Self) SelfBytes {
-        const size = @sizeOf(Self) + self.length;
-        return @as([*]align(@alignOf(Self)) u8, @ptrCast(self))[0..size];
+    fn fromBytesAux(
+        comptime packet: PacketType,
+        len: u16,
+        r: std.io.FixedBufferStream([]const u8).Reader,
+        allocator: Allocator,
+    ) !Message {
+        const Header = @field(@FieldType(Message, @tagName(packet)), "Header");
+
+        // Read the header for the current message type.
+        var header_bytes: [@sizeOf(Header)]u8 = undefined;
+        _ = try r.read(header_bytes[0 .. @bitSizeOf(Header) / 8]);
+        var header_stream = std.io.fixedBufferStream(&header_bytes);
+        const header = try header_stream.reader().readStructEndian(Header, .big);
+
+        // Read the base64 bytes into a list to be able to call the decoder on it.
+        const payload_buf = try allocator.alloc(u8, len - @bitSizeOf(Header) / 8);
+        defer allocator.free(payload_buf);
+        _ = try r.readAll(payload_buf);
+
+        // Create a buffer to store the payload in, and decode the base64 bytes into the payload field.
+        const payload = try allocator.alloc(u8, try base64Dec.calcSizeForSlice(payload_buf));
+        try base64Dec.decode(payload, payload_buf);
+
+        // Return the type of Message specified by the `packet` argument.
+        return @unionInit(Message, @tagName(packet), .{
+            .header = header,
+            .payload = payload,
+        });
+    }
+
+    /// Caller is responsible for calling .deinit on the returned value.
+    pub fn fromBytes(bytes: []const u8, allocator: Allocator) !Message {
+        var s = std.io.fixedBufferStream(bytes);
+        const r = s.reader();
+
+        // Read packet type
+        const packet_type = @as(PacketType, @enumFromInt(try r.readInt(u16, .big)));
+
+        // Read the length of the header + base64 encoded payload.
+        const len = try r.readInt(u16, .big);
+
+        switch (packet_type) {
+            .relay => return fromBytesAux(.relay, len, r, allocator),
+            .connection => return fromBytesAux(.connection, len, r, allocator),
+            .file_transfer => return Error.NotImplementedSaprusType,
+            else => return Error.UnknownSaprusType,
+        }
     }
 };
 
-test "testing variable length zero copy struct" {
-    {
-        // Relay test
-        const payload = "Hello darkness my old friend";
-        var msg_bytes: [try Message.calcSize(.relay, payload.len)]u8 align(@alignOf(Message)) = undefined;
-
-        // Create a view of the byte slice as a Message
-        const msg: *Message = .init(.relay, &msg_bytes);
-
-        {
-            // Set the message values
-            {
-                // These are both set by the init call.
-                // msg.type = .relay;
-                // msg.length = payload_len;
-            }
-            const relay = (try msg.getSaprusTypePayload()).relay;
-            relay.dest = .{ 1, 2, 3, 4 };
-            @memcpy(relay.getPayload(), payload);
-        }
-
-        {
-            // Print the message as hex using the network byte order
-            try msg.networkFromNativeEndian();
-            // We know the error from nativeFromNetworkEndian is unreachable because
-            // it would have returned an error from networkFromNativeEndian.
-            defer msg.nativeFromNetworkEndian() catch unreachable;
-            std.debug.print("relay network bytes: {x}\n", .{msg_bytes});
-            std.debug.print("bytes len: {d}\n", .{msg_bytes.len});
-        }
-
-        if (false) {
-            // Illegal behavior
-            std.debug.print("{any}\n", .{(try msg.getSaprusTypePayload()).connection});
-        }
-
-        try std.testing.expectEqualDeep(msg, try Message.bytesAsValue(msg.asBytes()));
-    }
-
-    {
-        // Connection test
-        const payload = "Hello darkness my old friend";
-        var msg_bytes: [try Message.calcSize(.connection, payload.len)]u8 align(@alignOf(Message)) = undefined;
-
-        // Create a view of the byte slice as a Message
-        const msg: *Message = .init(.connection, &msg_bytes);
-
-        {
-            // Initializing connection header values
-            const connection = (try msg.getSaprusTypePayload()).connection;
-            connection.src_port = 1;
-            connection.dest_port = 2;
-            connection.seq_num = 3;
-            connection.msg_id = 4;
-            connection.reserved = 5;
-            connection.options = @bitCast(@as(u8, 6));
-            @memcpy(connection.getPayload(), payload);
-        }
-
-        {
-            // Print the message as hex using the network byte order
-            try msg.networkFromNativeEndian();
-            // We know the error from nativeFromNetworkEndian is unreachable because
-            // it would have returned an error from networkFromNativeEndian.
-            defer msg.nativeFromNetworkEndian() catch unreachable;
-            std.debug.print("connection network bytes: {x}\n", .{msg_bytes});
-            std.debug.print("bytes len: {d}\n", .{msg_bytes.len});
-        }
-    }
-}
-
 const std = @import("std");
 const Allocator = std.mem.Allocator;
 
 const asBytes = std.mem.asBytes;
 const nativeToBig = std.mem.nativeToBig;
-const bigToNative = std.mem.bigToNative;
 
 test "Round trip Relay toBytes and fromBytes" {
-    if (false) {
     const gpa = std.testing.allocator;
     const msg = Message{
         .relay = .{
@@ -285,11 +188,8 @@ test "Round trip Relay toBytes and fromBytes" {
 
     try std.testing.expectEqualDeep(msg, from_bytes);
 }
-    return error.SkipZigTest;
-}
 
 test "Round trip Connection toBytes and fromBytes" {
-    if (false) {
     const gpa = std.testing.allocator;
     const msg = Message{
         .connection = .{
@@ -309,9 +209,3 @@ test "Round trip Connection toBytes and fromBytes" {
 
     try std.testing.expectEqualDeep(msg, from_bytes);
 }
-    return error.SkipZigTest;
-}
-
-test {
-    std.testing.refAllDeclsRecursive(@This());
-}

src/root.zig

@@ -1,12 +1,4 @@
 pub const Client = @import("Client.zig");
-pub const Connection = @import("Connection.zig");
-pub const RawSocketWriter = @import("RawSocketWriter.zig");
+pub usingnamespace @import("message.zig");
 
-const msg = @import("message.zig");
-
-pub const PacketType = msg.PacketType;
-pub const foo = msg.foo;
-pub const ConnectionOptions = msg.ConnectionOptions;
-pub const MessageTypeError = msg.MessageTypeError;
-pub const MessageParseError = msg.MessageParseError;
-pub const Message = msg.Message;
+pub usingnamespace @import("c_api.zig");