mirror of
https://git.robbyzambito.me/zaprus
synced 2025-12-20 08:14:50 +00:00
add comments!!!!!
This commit is contained in:
24
src/main.zig
24
src/main.zig
@@ -2,6 +2,8 @@ const is_debug = builtin.mode == .Debug;
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const base64Enc = std.base64.Base64Encoder.init(std.base64.standard_alphabet_chars, '=');
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const base64Dec = std.base64.Base64Decoder.init(std.base64.standard_alphabet_chars, '=');
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/// Type tag for SaprusMessage union.
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/// This is the first value in the actual packet sent over the network.
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const SaprusPacketType = enum(u16) {
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relay = 0x003C,
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file_transfer = 0x8888,
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@@ -9,6 +11,8 @@ const SaprusPacketType = enum(u16) {
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_,
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};
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/// Reserved option values.
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/// Currently unused.
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const SaprusConnectionOptions = packed struct(u8) {
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opt1: bool = false,
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opt2: bool = false,
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@@ -25,6 +29,7 @@ const SaprusError = error{
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UnknownSaprusType,
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};
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/// All Saprus messages
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const SaprusMessage = union(SaprusPacketType) {
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const Relay = struct {
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const Header = packed struct {
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@@ -49,6 +54,7 @@ const SaprusMessage = union(SaprusPacketType) {
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file_transfer: void, // unimplemented
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connection: Connection,
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/// Should be called for any SaprusMessage that was declared using a function that you pass an allocator to.
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fn deinit(self: SaprusMessage, allocator: Allocator) void {
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switch (self) {
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.relay => |r| allocator.free(r.payload),
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@@ -64,27 +70,39 @@ const SaprusMessage = union(SaprusPacketType) {
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w: std.ArrayList(u8).Writer,
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allocator: Allocator,
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) !void {
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// Create a growable string to store the base64 bytes in.
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// Doing this first so I can use the length of the encoded bytes for the length field.
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var payload_list = std.ArrayList(u8).init(allocator);
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defer payload_list.deinit();
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const buf_w = payload_list.writer();
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// Write the payload bytes as base64 to the growable string.
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try base64Enc.encodeWriter(buf_w, payload);
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// Write the packet body to the output writer.
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try w.writeStructEndian(header, .big);
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try w.writeInt(u16, @intCast(payload_list.items.len), .big);
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try w.writeAll(payload_list.items);
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}
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/// Caller is responsible for freeing the returned bytes.
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fn toBytes(self: SaprusMessage, allocator: Allocator) ![]u8 {
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// Create a growable list of bytes to store the output in.
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var buf = std.ArrayList(u8).init(allocator);
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// Create a writer for an easy interface to append arbitrary bytes.
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const w = buf.writer();
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// Start with writing the message type, which is the first 16 bits of every Saprus message.
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try w.writeInt(u16, @intFromEnum(self), .big);
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// Write the proper header and payload for the given packet type.
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switch (self) {
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.relay => |r| try toBytesAux(Relay.Header, r.header, r.payload, w, allocator),
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.connection => |c| try toBytesAux(Connection.Header, c.header, c.payload, w, allocator),
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.file_transfer => return SaprusError.NotImplementedSaprusType,
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}
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// Collect the growable list as a slice and return it.
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return buf.toOwnedSlice();
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}
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@@ -94,22 +112,28 @@ const SaprusMessage = union(SaprusPacketType) {
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r: std.io.FixedBufferStream([]const u8).Reader,
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allocator: Allocator,
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) !SaprusMessage {
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// Read the header for the current message type.
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const header = try r.readStructEndian(Header, .big);
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// Read the length of the base64 encoded payload.
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const len = try r.readInt(u16, .big);
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// Read the base64 bytes into a list to be able to call the decoder on it.
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var payload_buf = std.ArrayList(u8).init(allocator);
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defer payload_buf.deinit();
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try r.readAllArrayList(&payload_buf, len);
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// Create a buffer to store the payload in, and decode the base64 bytes into the payload field.
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const payload = try allocator.alloc(u8, try base64Dec.calcSizeForSlice(payload_buf.items));
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try base64Dec.decode(payload, payload_buf.items);
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// Return the type of SaprusMessage specified by the `packet` argument.
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return @unionInit(SaprusMessage, @tagName(packet), .{
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.header = header,
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.payload = payload,
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});
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}
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/// Caller is responsible for calling .deinit on the returned value.
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fn fromBytes(bytes: []const u8, allocator: Allocator) !SaprusMessage {
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var s = std.io.fixedBufferStream(bytes);
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const r = s.reader();
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