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
183
184
185
186
187
188
189
190
|
.TH RUNE 3
.SH NAME
runetochar, chartorune, runelen, runenlen, fullrune, utfecpy, utflen, utfnlen, utfrune, utfrrune, utfutf \- rune/UTF conversion
.SH SYNOPSIS
.ta \w'\fLchar*xx'u
.B #include <u.h>
.br
.B #include <libc.h>
.PP
.B
int runetochar(char *s, Rune *r)
.PP
.B
int chartorune(Rune *r, char *s)
.PP
.B
int runelen(long r)
.PP
.B
int runenlen(Rune *r, int n)
.PP
.B
int fullrune(char *s, int n)
.PP
.B
char* utfecpy(char *s1, char *es1, char *s2)
.PP
.B
int utflen(char *s)
.PP
.B
int utfnlen(char *s, long n)
.PP
.B
char* utfrune(char *s, long c)
.PP
.B
char* utfrrune(char *s, long c)
.PP
.B
char* utfutf(char *s1, char *s2)
.SH DESCRIPTION
These routines convert to and from a
.SM UTF
byte stream and runes.
.PP
.I Runetochar
copies one rune at
.I r
to at most
.B UTFmax
bytes starting at
.I s
and returns the number of bytes copied.
.BR UTFmax ,
defined as
.B 3
in
.BR <libc.h> ,
is the maximum number of bytes required to represent a rune.
.PP
.I Chartorune
copies at most
.B UTFmax
bytes starting at
.I s
to one rune at
.I r
and returns the number of bytes copied.
If the input is not exactly in
.SM UTF
format,
.I chartorune
will convert to 0x80 and return 1.
.PP
.I Runelen
returns the number of bytes
required to convert
.I r
into
.SM UTF.
.PP
.I Runenlen
returns the number of bytes
required to convert the
.I n
runes pointed to by
.I r
into
.SM UTF.
.PP
.I Fullrune
returns 1 if the string
.I s
of length
.I n
is long enough to be decoded by
.I chartorune
and 0 otherwise.
This does not guarantee that the string
contains a legal
.SM UTF
encoding.
This routine is used by programs that
obtain input a byte at
a time and need to know when a full rune
has arrived.
.PP
The following routines are analogous to the
corresponding string routines with
.B utf
substituted for
.B str
and
.B rune
substituted for
.BR chr .
.PP
.I Utfecpy
copies UTF sequences until a null sequence has been copied, but writes no
sequences beyond
.IR es1 .
If any sequences are copied,
.I s1
is terminated by a null sequence, and a pointer to that sequence is returned.
Otherwise, the original
.I s1
is returned.
.PP
.I Utflen
returns the number of runes that
are represented by the
.SM UTF
string
.IR s .
.PP
.I Utfnlen
returns the number of complete runes that
are represented by the first
.I n
bytes of
.SM UTF
string
.IR s .
If the last few bytes of the string contain an incompletely coded rune,
.I utfnlen
will not count them; in this way, it differs from
.IR utflen ,
which includes every byte of the string.
.PP
.I Utfrune
.RI ( utfrrune )
returns a pointer to the first (last)
occurrence of rune
.I c
in the
.SM UTF
string
.IR s ,
or 0 if
.I c
does not occur in the string.
The NUL byte terminating a string is considered to
be part of the string
.IR s .
.PP
.I Utfutf
returns a pointer to the first occurrence of
the
.SM UTF
string
.I s2
as a
.SM UTF
substring of
.IR s1 ,
or 0 if there is none.
If
.I s2
is the null string,
.I utfutf
returns
.IR s1 .
.SH SOURCE
.B /sys/src/libc/port/rune.c
.br
.B /sys/src/libc/port/utfrune.c
.SH SEE ALSO
.IR utf (6),
.IR tcs (1)
|