a geicko-2 based round robin ranking system designed to test c++ battleship submissions
battleship.dunkirk.sh
dunkirk.sh
1// Copyright 2012 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package ssh
6
7import (
8 "io"
9 "sync"
10)
11
12// buffer provides a linked list buffer for data exchange
13// between producer and consumer. Theoretically the buffer is
14// of unlimited capacity as it does no allocation of its own.
15type buffer struct {
16 // protects concurrent access to head, tail and closed
17 *sync.Cond
18
19 head *element // the buffer that will be read first
20 tail *element // the buffer that will be read last
21
22 closed bool
23}
24
25// An element represents a single link in a linked list.
26type element struct {
27 buf []byte
28 next *element
29}
30
31// newBuffer returns an empty buffer that is not closed.
32func newBuffer() *buffer {
33 e := new(element)
34 b := &buffer{
35 Cond: newCond(),
36 head: e,
37 tail: e,
38 }
39 return b
40}
41
42// write makes buf available for Read to receive.
43// buf must not be modified after the call to write.
44func (b *buffer) write(buf []byte) {
45 b.Cond.L.Lock()
46 e := &element{buf: buf}
47 b.tail.next = e
48 b.tail = e
49 b.Cond.Signal()
50 b.Cond.L.Unlock()
51}
52
53// eof closes the buffer. Reads from the buffer once all
54// the data has been consumed will receive io.EOF.
55func (b *buffer) eof() {
56 b.Cond.L.Lock()
57 b.closed = true
58 b.Cond.Signal()
59 b.Cond.L.Unlock()
60}
61
62// Read reads data from the internal buffer in buf. Reads will block
63// if no data is available, or until the buffer is closed.
64func (b *buffer) Read(buf []byte) (n int, err error) {
65 b.Cond.L.Lock()
66 defer b.Cond.L.Unlock()
67
68 for len(buf) > 0 {
69 // if there is data in b.head, copy it
70 if len(b.head.buf) > 0 {
71 r := copy(buf, b.head.buf)
72 buf, b.head.buf = buf[r:], b.head.buf[r:]
73 n += r
74 continue
75 }
76 // if there is a next buffer, make it the head
77 if len(b.head.buf) == 0 && b.head != b.tail {
78 b.head = b.head.next
79 continue
80 }
81
82 // if at least one byte has been copied, return
83 if n > 0 {
84 break
85 }
86
87 // if nothing was read, and there is nothing outstanding
88 // check to see if the buffer is closed.
89 if b.closed {
90 err = io.EOF
91 break
92 }
93 // out of buffers, wait for producer
94 b.Cond.Wait()
95 }
96 return
97}