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
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
const true = 1;
const false = 0;
// This should really be a constant, but we only allow integers...
let null: void*; // Zero initialized by default.
///////////////////////////////////////////////////////////////////////////////
// Syscalls
fn write(fd: int, s: void*, n: int): int {
return syscall3(SYS_write, fd, s, n);
}
fn exit(status: int): int {
return syscall1(SYS_exit, status);
}
fn read(fd: int, s: void*, n: int): int {
return syscall3(SYS_read, fd, s, n);
}
fn open(path: char*, flags: int, mode: int): int {
return syscall3(SYS_open, path, flags, mode);
}
fn openat(fd: int, path: char*, flags: int, mode: int): int {
return syscall4(SYS_openat, fd, path, flags, mode);
}
fn fork(): int {
return syscall0(SYS_fork);
}
fn wait(status: int*): int {
return syscall4(SYS_wait4, -1, status, 0, 0);
}
///////////////////////////////////////////////////////////////////////////////
// Strings
fn strlen(s: char *): int {
let count: int = 0;
while (*s != 0) {
count = count + 1;
s = s + 1;
}
return count;
}
fn strcpy(dst: char *, src: char *) {
while (*src != 0) {
*dst = *src;
dst = dst + 1;
src = src + 1;
}
*dst = '\0';
}
fn strcat(dst: char *, src: char *) {
while (*dst != 0) {
dst = dst + 1;
}
while (*src != 0) {
*dst = *src;
dst = dst + 1;
src = src + 1;
}
*dst = '\0';
}
fn streq(s1: char *, s2: char *): int {
while (*s1 != 0 && *s2 != 0) {
if (*s1 != *s2)
return 0;
s1 = s1 + 1;
s2 = s2 + 1;
}
return *s1 == *s2;
}
fn strrev(s: char *) {
let len: int = strlen(s);
let i: int = 0;
let j: int = len - 1;
while (i < j) {
let tmp: char = s[i];
s[i] = s[j];
s[j] = tmp;
i = i + 1;
j = j - 1;
}
}
fn atoi_end(s: char *, end: char**): int {
let i: int = 0;
let sign: int = 1;
if (*s == '-') {
sign = -1;
s = s + 1;
}
while (*s >= '0' && *s <= '9') {
i = i * 10 + (*s - '0');
s = s + 1;
}
*end = s;
return i * sign;
}
fn atoi(s: char *): int {
let tmp: char*;
return atoi_end(s, &tmp);
}
///////////////////////////////////////////////////////////////////////////////
// I/O
const stdin = 0;
const stdout = 1;
const stderr = 2;
fn putc(c: char) {
write(0, &c, 1);
}
fn puts(c: char *) {
let len: int = strlen(c);
write(1, c, len);
}
fn putsln(c: char *) {
puts(c);
putc('\n');
}
fn putu(n: int) {
let buf: char[32];
let i: int = 0;
while (n > 0) {
buf[i] = (n % 10) + '0';
n = n / 10;
i = i + 1;
}
if (i == 0)
buf[i] = '0';
else
strrev(buf);
write(0, buf, i);
}
fn die(msg: char *) {
putsln(msg);
exit(1);
}
///////////////////////////////////////////////////////////////////////////////
// Math
fn min(a: int, b: int): int {
return a < b ? a : b;
}
fn max(a: int, b: int): int {
return a > b ? a : b;
}
fn sign(a: int): int {
return a > 0 ? 1 : a == 0 ? 0 : -1;
}
fn abs(a: int): int {
return a * sign(a);
}
fn factorial(n: int): int {
let res: int = 1;
for (;n > 0; n = n - 1)
res = res * n;
return res;
}
|