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
|
# re2py $INPUT -o $OUTPUT
class State:
def __init__(self, str):
self.yyinput = str
self.yycursor = 0
self.yymarker = 0
# Common re2c definitions shared between all functions.
%{
re2c:api = record;
re2c:yyrecord = st;
re2c:yyfill:enable = 0;
re2c:indent:top = 2;
%}
def parse_u32(str):
st = State(str)
%{local
re2c:indent:top = 1;
'0b' / [01] { return parse_bin(st) }
"0" { return parse_oct(st) }
"" / [1-9] { return parse_dec(st) }
'0x' / [0-9a-fA-F] { return parse_hex(st) }
* { return None }
%}
def parse_bin(st):
n = 0
while True: %{
[01] {
n = n * 2 + (st.yyinput[st.yycursor - 1] - 48)
break
}
* { return n }
%}
def parse_oct(st):
n = 0
while True: %{
[0-7] {
n = n * 8 + (st.yyinput[st.yycursor - 1] - 48)
break
}
* { return n }
%}
def parse_dec(st):
n = 0
while True: %{
[0-9] {
n = n * 10 + (st.yyinput[st.yycursor - 1] - 48)
break
}
* { return n }
%}
def parse_hex(st):
n = 0
while True: %{
[0-9] {
n = n * 16 + (st.yyinput[st.yycursor - 1] - 48)
break
}
[a-f] {
n = n * 16 + (st.yyinput[st.yycursor - 1] - 87)
break
}
[A-F] {
n = n * 16 + (st.yyinput[st.yycursor - 1] - 55)
break
}
* { return n }
%}
assert parse_u32(b"\0") == None
assert parse_u32(b"1234567890\0") == 1234567890
assert parse_u32(b"0b1101\0") == 13
assert parse_u32(b"0x7Fe\0") == 2046
assert parse_u32(b"0644\0") == 420
assert parse_u32(b"9999999999\0") == 9999999999
|
