Big changes to the C api implementations

Should map directly to the zig struct instead of mallocing

build.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const Step = std.Build.Step;
 
 // Although this function looks imperative, note that its job is to
 // declaratively construct a build graph that will be executed by an external
@@ -37,13 +38,29 @@ pub fn build(b: *std.Build) void {
     exe_mod.addImport("zaprus", lib_mod);
     exe_mod.addImport("clap", b.dependency("clap", .{}).module("clap"));
 
-    const lib = b.addLibrary(.{
+    const static_lib = b.addLibrary(.{
         .linkage = .static,
         .name = "zaprus",
         .root_module = lib_mod,
     });
+    static_lib.addIncludePath(.{ .cwd_relative = "include" });
+    static_lib.linkLibC();
 
-    b.installArtifact(lib);
+    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.

include/zaprus.h

@@ -0,0 +1,46 @@
+// 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);
+
+struct SaprusMessage* zaprus_connect(const char* payload, size_t len);
+
+// message
+#define SAPRUS_RELAY_MESSAGE_TYPE 0x003C
+#define SAPRUS_FILE_TRANSFER_MESSAGE_TYPE 0x8888
+#define SAPRUS_CONNECTION_MESSAGE_TYPE 0x00E9
+
+struct SaprusMessage {
+  uint16_t packet_type;
+  uint16_t payload_len;
+  union {
+    struct {
+      char dest[4];
+    } relay;
+    struct {
+      uint16_t src_port;
+      uint16_t dest_port;
+      uint32_t seq_num;
+      uint32_t msg_id;
+      char _reserved;
+      char options;
+    } connection;
+  } headers;
+  char *payload;
+};
+
+// ptr should be freed by the caller.
+int zaprus_message_to_bytes(struct SaprusMessage msg, char** ptr, size_t* len);
+
+// Return value should be destroyed with zaprus_message_deinit.
+struct SaprusMessage* zaprus_message_from_bytes(const char* bytes, size_t len);
+
+void zaprus_message_deinit(struct SaprusMessage* msg);

src/Client.zig

@@ -76,7 +76,7 @@ pub fn sendInitialConnection(payload: []const u8, initial_port: u16, allocator:
     return msg;
 }
 
-pub fn connect(payload: []const u8, allocator: Allocator) !?SaprusMessage {
+pub fn connect(payload: []const u8, allocator: Allocator) !SaprusMessage {
     var initial_port: u16 = 0;
     if (rand) |r| {
         initial_port = r.intRangeAtMost(u16, 1024, 65000);
@@ -109,7 +109,7 @@ pub fn connect(payload: []const u8, allocator: Allocator) !?SaprusMessage {
     // Complete handshake after awaiting response
     try broadcastSaprusMessage(msg, randomPort(), allocator);
 
-    return initial_conn_res;
+    return initial_conn_res.?;
 }
 
 const SaprusMessage = @import("message.zig").Message;

src/c_api.zig

@@ -0,0 +1,126 @@
+const c = @cImport({
+    @cInclude("zaprus.h");
+});
+
+fn zigToCMessage(msg: zaprus.Message) !c.SaprusMessage {
+    return switch (msg) {
+        .relay => |r| .{
+            .packet_type = @intFromEnum(msg),
+            .payload_len = @intCast(r.payload.len),
+            .headers = .{ .relay = .{
+                .dest = r.header.dest,
+            } },
+            .payload = @constCast(r.payload.ptr),
+        },
+        .connection => |con| .{
+            .packet_type = @intFromEnum(msg),
+            .payload_len = @intCast(con.payload.len),
+            .headers = .{ .connection = .{
+                .src_port = con.header.src_port,
+                .dest_port = con.header.dest_port,
+                .seq_num = con.header.seq_num,
+                .msg_id = con.header.msg_id,
+                ._reserved = con.header.reserved,
+                .options = @bitCast(con.header.options),
+            } },
+            .payload = @constCast(con.payload.ptr),
+        },
+        .file_transfer => return zaprus.Error.NotImplementedSaprusType,
+        else => return zaprus.Error.UnknownSaprusType,
+    };
+}
+
+fn cToZigMessage(msg: c.SaprusMessage) !zaprus.Message {
+    const msg_type: zaprus.PacketType = @enumFromInt(msg.packet_type);
+    return switch (msg_type) {
+        .relay => .{
+            .relay = .{
+                .header = .{
+                    .dest = msg.headers.relay.dest[0..4].*,
+                },
+                .payload = msg.payload[0..msg.payload_len],
+            },
+        },
+        .connection => .{
+            .connection = .{
+                .header = .{
+                    .src_port = msg.headers.connection.src_port,
+                    .dest_port = msg.headers.connection.dest_port,
+                    .seq_num = msg.headers.connection.seq_num,
+                    .msg_id = msg.headers.connection.msg_id,
+                    .reserved = msg.headers.connection._reserved,
+                    .options = @bitCast(msg.headers.connection.options),
+                },
+                .payload = msg.payload[0..msg.payload_len],
+            },
+        },
+        .file_transfer => return zaprus.Error.NotImplementedSaprusType,
+        else => return zaprus.Error.UnknownSaprusType,
+    };
+}
+
+// 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_send_initial_connection(payload: [*]const u8, len: usize, initial_port: u16) c_int {
+    _ = SaprusClient.sendInitialConnection(payload[0..len], initial_port, allocator) catch return 1;
+    return 0;
+}
+
+export fn zaprus_connect(payload: [*]const u8, len: usize) ?*c.SaprusMessage {
+    if (SaprusClient.connect(payload[0..len], allocator)) |msg| {
+        var m = zigToCMessage(msg) catch return null;
+        return &m;
+    } else |_| {
+        return null;
+    }
+}
+
+// message
+
+/// ptr should be freed by the caller.
+export fn zaprus_message_to_bytes(msg: c.SaprusMessage, ptr: *[*]u8, len: *usize) c_int {
+    var m = cToZigMessage(msg) catch return 1;
+    const bytes = m.toBytes(allocator) catch return 1;
+    ptr.* = bytes.ptr;
+    len.* = bytes.len;
+    return 0;
+}
+
+/// Return value should be destroyed with zaprus_message_deinit.
+export fn zaprus_message_from_bytes(bytes: [*]const u8, len: usize) ?*c.SaprusMessage {
+    if (zaprus.Message.fromBytes(bytes[0..len], allocator)) |msg| {
+        var m = zigToCMessage(msg) catch return null;
+        return &m;
+    } else |_| return null;
+}
+
+export fn zaprus_message_deinit(msg: *c.SaprusMessage) void {
+    if (cToZigMessage(msg.*)) |m| {
+        m.deinit(allocator);
+    } else |_| unreachable;
+}
+
+const std = @import("std");
+
+const zaprus = @import("./root.zig");
+const SaprusClient = zaprus.Client;
+
+const allocator = std.heap.c_allocator;
+
+test {
+    std.testing.refAllDeclsRecursively(@This());
+}

src/main.zig

@@ -75,7 +75,7 @@ pub fn main() !void {
     return clap.help(std.io.getStdErr().writer(), clap.Help, &params, .{});
 }
 
-fn parseDest(in: ?[]const u8) [4]u8 {
+fn parseDest(in: ?[]const u8) ![4]u8 {
     if (in) |dest| {
         if (dest.len <= 4) {
             var res: [4]u8 = @splat(0);
@@ -83,10 +83,10 @@ fn parseDest(in: ?[]const u8) [4]u8 {
             return res;
         }
 
-        const addr = std.net.Ip4Address.parse(dest, 0) catch return "FAIL".*;
+        const addr = try std.net.Ip4Address.parse(dest, 0);
         return @bitCast(addr.sa.addr);
     }
-    return "zap".*;
+    return "FAIL".*;
 }
 
 const builtin = @import("builtin");

src/root.zig

@@ -1,2 +1,4 @@
 pub const Client = @import("Client.zig");
 pub usingnamespace @import("message.zig");
+
+pub usingnamespace @import("c_api.zig");