zaprus/src/c_api.zig

const c = @cImport({
    @cInclude("zaprus.h");
});

fn zigToCMessage(msg: ?*zaprus.Message) !?*c.SaprusMessage {
    if (msg) |m| {
        var res = c.SaprusMessage{
            .packet_type = @intFromEnum(m.*),
        };
        switch (m.*) {
            .relay => |r| {
                res.headers.relay = .{
                    .dest = r.header.dest,
                };
                res.payload_len = @intCast(r.payload.len);
                res.payload = (try allocator.alloc(u8, r.payload.len)).ptr;
            },
            .connection => |con| {
                res.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),
                };

                res.payload_len = @intCast(con.payload.len);
                res.payload = (try allocator.alloc(u8, con.payload.len)).ptr;
            },
            .file_transfer => return zaprus.Error.NotImplementedSaprusType,
            else => return zaprus.Error.UnknownSaprusType,
        }
        return &res;
    } else return null;
}

fn cToZigMessage(msg: ?*c.SaprusMessage) !?*zaprus.Message {
    if (msg) |m| {
        const msg_type: zaprus.PacketType = @enumFromInt(m.*.packet_type);
        var res: zaprus.Message = switch (msg_type) {
            .relay => .{
                .relay = .{
                    .header = .{
                        .dest = m.*.headers.relay.dest[0..4].*,
                    },
                    .payload = blk: {
                        const p = try allocator.alloc(u8, m.payload_len);
                        @memcpy(p, m.payload[0..m.payload_len]);
                        break :blk p;
                    },
                },
            },
            .connection => .{
                .connection = .{
                    .header = .{
                        .src_port = m.*.headers.connection.src_port,
                        .dest_port = m.*.headers.connection.dest_port,
                        .seq_num = m.*.headers.connection.seq_num,
                        .msg_id = m.*.headers.connection.msg_id,
                        .reserved = m.*.headers.connection._reserved,
                        .options = @bitCast(m.*.headers.connection.options),
                    },
                    .payload = blk: {
                        const p = try allocator.alloc(u8, m.payload_len);
                        @memcpy(p, m.payload[0..m.payload_len]);
                        break :blk p;
                    },
                },
            },
            .file_transfer => return zaprus.Error.NotImplementedSaprusType,
            else => return zaprus.Error.UnknownSaprusType,
        };

        return &res;
    } else return null;
}

// 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| {
        return zigToCMessage(@constCast(&(msg.?))) catch null;
    } 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 {
    if (cToZigMessage(@constCast(&msg)) catch return 1) |m| {
        const bytes = m.toBytes(allocator) catch return 1;
        ptr.* = bytes.ptr;
        len.* = bytes.len;
        return 0;
    } else return 1;
}

/// 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| {
        return zigToCMessage(@constCast(&msg)) catch null;
    } else |_| return null;
}

export fn zaprus_message_deinit(msg: *c.SaprusMessage) void {
    // noop
    _ = msg;
    // msg.*.deinit(allocator);
}

const std = @import("std");

const zaprus = @import("./root.zig");
const SaprusClient = zaprus.Client;

const allocator = std.heap.c_allocator;

test {
    std.testing.refAllDeclsRecursively(@This());
}