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utf: fix string length calculation for combining characters

This commit is contained in:
Uwe Krüger 2020-05-04 13:21:11 +02:00 committed by GitHub
parent a72f3ed0c7
commit f831910c5c
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3 changed files with 43 additions and 3 deletions

View File

@ -174,7 +174,7 @@ fn utf8_len(c byte) int {
return b
}
// Calculate string length for formatting, i.e. number of "characters"
// Calculate string length for in number of codepoints
fn utf8_str_len(s string) int {
mut l := 0
for i := 0; i < s.len; i++ {
@ -189,6 +189,41 @@ fn utf8_str_len(s string) int {
return l
}
// Calculate string length for formatting, i.e. number of "characters"
fn utf8_str_visible_length(s string) int {
mut l := 0
mut ul := 1
for i := 0; i < s.len; i+=ul {
ul = 1
c := s.str[i]
if (c & (1 << 7)) != 0 {
for t := byte(1 << 6); (c & t) != 0; t >>= 1 {
ul++
}
}
if i + ul > s.len { // incomplete UTF-8 sequence
return l
}
l++
// recognize combining characters
if c == 0xcc || c == 0xcd {
r := (u16(c) << 8) | s.str[i+1]
if r >= 0xcc80 && r < 0xcdb0 { // diacritical marks
l--
}
} else if c == 0xe1 || c == 0xe2 || c == 0xef {
r := (u32(c) << 16) | (u32(s.str[i+1]) << 8) | s.str[i+2]
if r >= 0xe1aab0 && r < 0xe1ac80 // diacritical marks extended
|| r >= 0xe1b780 && r < 0xe1b880 // diacritical marks supplement
|| r >= 0xe28390 && r < 0xe28480 // diacritical marks for symbols
|| r >= 0xefb8a0 && r < 0xefb8b0 { // half marks
l--
}
}
}
return l
}
// Reads an utf8 character from standard input
pub fn utf8_getchar() int {
c := C.getchar()

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@ -57,9 +57,9 @@ string _STR(const char *fmt, int nfmts, ...) {
if (fmt[k-4] == '*') { // %*.*s
int fwidth = va_arg(argptr, int);
if (fwidth < 0)
fwidth -= (s.len - utf8_str_len(s));
fwidth -= (s.len - utf8_str_visible_length(s));
else
fwidth += (s.len - utf8_str_len(s));
fwidth += (s.len - utf8_str_visible_length(s));
_STR_PRINT_ARG(fmt, &buf, &nbytes, &memsize, k+fwidth-4, fwidth, s.len, s.str);
} else { // %.*s
_STR_PRINT_ARG(fmt, &buf, &nbytes, &memsize, k+s.len-4, s.len, s.str);

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@ -102,6 +102,11 @@ fn test_utf8_string_interpolation() {
e := '\u20AC' // Eurosign
// TODO: this fails with MSVC and tcc
// assert '100.00 $e' == '100.00 €'
m2 := 'Москва́' // cyrillic а́: combination of U+0430 and U+0301, UTF-8: d0 b0 cc 81
d := 'Antonín Dvořák' // latin á: U+00E1, UTF-8: c3 a1
assert ':${m2:7}:${d:-15}:' == ': Москва́:Antonín Dvořák :'
g := 'Πελοπόννησος'
assert '>${g:-13}<' == '>Πελοπόννησος <'
}
struct S {