1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
use io;
use fmt;
use endian;
use drawing;
use drawing::{pos,CHUNKSIZE};
export def VERSION: u8 = 1;
export type error = !str;
export type packet_reader = struct {
buf: []u8,
good: []u8,
};
export fn new() packet_reader = {
let pr = packet_reader {
buf = alloc([0...],512*512*4*2), // ehhh
...
};
pr.good = pr.buf[0..0];
return pr;
};
fn cast_u32s_to_u8s(in: []u32) []u8 =
(in: *[*]u32: *[*]u8)[..len(in)*4];
fn cast_u8s_to_u32s(in: []u8) []u32 =
(in: *[*]u8: *[*]u32)[..len(in)/4];
export type packet_type = enum u8 {
DRAW_OP,
SEND_CHUNK,
POSITION,
REQ_CHUNK
};
export type packet_drawop = drawing::op;
export type packet_sendchunk = struct {
world_pos: pos,
chunk_data: []u32,
};
export type packet_position = pos;
export type packet_reqchunk = pos;
export type packet = (
packet_drawop
| packet_sendchunk
| packet_position
| packet_reqchunk);
// call when input is ready. could block otherwise
export fn read(pr: *packet_reader, sock: io::handle) (void | io::error | io::EOF) = {
const remaining_amt = len(pr.good);
const read_pos = if (remaining_amt > 0) {
// still some unconsumed content in the buffer
// move unconsumed stuff to start of buffer
// fmt::printfln("moving {} remaining bytes",remaining_amt)!;
pr.buf[0..remaining_amt] = pr.good;
yield remaining_amt;
} else 0z;
const nread = match(io::read(sock, pr.buf[read_pos..])?) {
case io::EOF => return io::EOF;
case let n: size => yield n;
};
// fmt::printfln("read {} bytes",nread)!;
const total_amt = read_pos + nread;
pr.good = pr.buf[0..total_amt];
// fmt::printfln("now {} bytes in buffer",total_amt)!;
};
// packet format:
// u32 size
// u32 type
// [size-8]u8 data...
// size includes size of header (size and type fields)
export fn next(pr: *packet_reader) (packet | done | error) = {
// either parse a full packet out of the front of good,
// move good along that many bytes,
// and return the packet,
// or, ascertain there is no full packet, and return done
if (len(pr.good) < size(u32)) return done;
const packet_len = endian::legetu32(pr.good[0..4]);
if (packet_len < 8) return "packet size field too small": error;
if (len(pr.good) < packet_len) return done;
const packet_bytes = pr.good[..packet_len];
pr.good = pr.good[packet_len..];
const ty = endian::legetu32(packet_bytes[4..8]): packet_type;
const payload = packet_bytes[8..];
switch (ty) {
case packet_type::DRAW_OP =>
match (drawing::deser_op(payload)) {
case let o: drawing::op => return o;
case drawing::deser_fail => return "deser fail": error;
};
case packet_type::SEND_CHUNK =>
// return value is BORROWED from the BUFFER
const pos_bytes = payload[0..8];
const chunk_data_bytes = payload[8..];
const pos = (
endian::legetu32(pos_bytes[0..4]): i32,
endian::legetu32(pos_bytes[4..8]): i32
): pos;
const d = cast_u8s_to_u32s(chunk_data_bytes);
if (len(d) != CHUNKSIZE*CHUNKSIZE)
return "wrong chunk size??": error;
return packet_sendchunk { world_pos = pos, chunk_data = d };
case packet_type::POSITION =>
if (len(payload) != 8)
return "position packet wrong size": error;
const pos = (
endian::legetu32(payload[0..4]): i32,
endian::legetu32(payload[4..8]): i32
): pos;
return pos: packet_position;
case packet_type::REQ_CHUNK =>
if (len(payload) != 8)
return "reqchunk packet wrong size": error;
const world_pos = (
endian::legetu32(payload[0..4]): i32,
endian::legetu32(payload[4..8]): i32
): pos;
if (world_pos.0 % CHUNKSIZE != 0 || world_pos.1 % CHUNKSIZE != 0) {
return "invalid world_pos": error;
};
return world_pos: packet_reqchunk;
};
};
export fn send_raw(sock: io::file, ty: packet_type, datas: []u8...) (void | io::error) = {
// ehh
const header: [8]u8 = [0...];
let total_len = 8u32;
for (const data .. datas) total_len += len(data): u32;
endian::leputu32(header[0..4], total_len);
endian::leputu32(header[4..8], ty);
io::writeall(sock, header)?;
for (const data .. datas)
io::writeall(sock, data)?;
};
export fn send(sock: io::file, packet: packet) (void | io::error) = {
match (packet) {
case let op: packet_drawop =>
const ser_op = drawing::ser_op(op);
defer free(ser_op);
send_raw(sock, packet_type::DRAW_OP, ser_op)?;
case let packet: packet_sendchunk =>
const pos_buf: [8]u8 = [0...];
endian::leputu32(pos_buf[0..4],packet.world_pos.0: u32);
endian::leputu32(pos_buf[4..8],packet.world_pos.1: u32);
const chunk_data_bytes = cast_u32s_to_u8s(packet.chunk_data);
send_raw(sock, packet_type::SEND_CHUNK, pos_buf, chunk_data_bytes)?;
case let pos: packet_position =>
const pos_buf: [8]u8 = [0...];
endian::leputu32(pos_buf[0..4], pos.0: u32);
endian::leputu32(pos_buf[4..8], pos.1: u32);
send_raw(sock, packet_type::POSITION, pos_buf)?;
case let world_pos: packet_reqchunk =>
const pos_buf: [8]u8 = [0...];
endian::leputu32(pos_buf[0..4], world_pos.0: u32);
endian::leputu32(pos_buf[4..8], world_pos.1: u32);
send_raw(sock, packet_type::REQ_CHUNK, pos_buf)?;
};
};
|
