RUNECOMP(2) RUNECOMP(2)
NAME
runecomp, runedecomp, fullrunenorm, runegbreak, runewbreak,
utfcomp, utfdecomp, fullutfnorm, utfgbreak, utfwbreak -
multi-rune graphemes
SYNOPSIS
#include <u.h>
#include <libc.h>
int runecomp(Rune *dst, Rune *src, int max)
int runedecomp(Rune *dst, Rune *src, int max)
Rune* fullrunenorm(Rune *s, int n)
Rune* runegbreak(Rune *s)
Rune* runewbreak(Rune *s)
int utfcomp(char *dst, char *src, int max)
int utfdecomp(char *dst, char *src, int max)
char* fullutfnorm(char *s, int n)
char* utfgbreak(char *s)
char* utfwbreak(char *s)
DESCRIPTION
These routines help in handling graphemes that may span mul-
tiple runes. These routines are for use in font rendering
and advanced text search; most programs do not need to per-
form normalization.
Runecomp, runedecomp, utfcomp, and utfdecomp perform Uni-
code® normalization on src, storing the result in dst. No
more than max elements will be written, and the resulting
string will always be null terminated. The return value is
always the total number of elements required to store the
transformation. If this value is larger than the supplied
max the caller can assume the result has been truncated.
Runecomp and utfcomp perform NFC normalization while
runedecomp and utfdecomp perform NFD normalization.
Fullrunenorm, and fullutfnorm determine if enough elements
are present in s to perform normalization. If enough are
present, a pointer is returned to the first element that
begins the next context. Otherwise s is returned. No more
then n elements will be read. In order to find the boundary,
RUNECOMP(2) RUNECOMP(2)
the first element of the next context must be peeked.
Runegbreak and utfgbreak search s for the next grapheme
break opportunity. If none is found before the end of the
string, s is returned.
Runewbreak and utfwbreak search s for the next word break
opportunity. If none is found before the end of the string,
s is returned.
SOURCE
/sys/src/libc/port/mkrunetype.c
/sys/src/libc/port/runenorm.c
/sys/src/libc/port/runebreak.c
SEE ALSO
Unicode® Standard Annex #15
Unicode® Standard Annex #29
rune(2), utf(6), tcs(1)
HISTORY
This implementation was written for 9front (March, 2023).