1
0
mirror of https://github.com/vlang/v.git synced 2023-08-10 21:13:21 +03:00
v/vlib/builtin/utf8.c.v

95 lines
3.0 KiB
V
Raw Normal View History

module builtin
import strings
const cp_utf8 = 65001
2020-12-15 12:01:51 +03:00
// to_wide returns a pointer to an UTF-16 version of the string receiver.
// In V, strings are encoded using UTF-8 internally, but on windows most APIs,
// that accept strings, need them to be in UTF-16 encoding.
// The returned pointer of .to_wide(), has a type of &u16, and is suitable
// for passing to Windows APIs that expect LPWSTR or wchar_t* parameters.
// See also MultiByteToWideChar ( https://learn.microsoft.com/en-us/windows/win32/api/stringapiset/nf-stringapiset-multibytetowidechar )
// See also builtin.wchar.from_string/1, for a version, that produces a
// platform dependant L"" C style wchar_t* wide string.
pub fn (_str string) to_wide() &u16 {
$if windows {
unsafe {
num_chars := (C.MultiByteToWideChar(cp_utf8, 0, &char(_str.str), _str.len,
0, 0))
mut wstr := &u16(malloc_noscan((num_chars + 1) * 2)) // sizeof(wchar_t)
if wstr != 0 {
C.MultiByteToWideChar(cp_utf8, 0, &char(_str.str), _str.len, wstr, num_chars)
2022-04-15 14:58:56 +03:00
C.memset(&u8(wstr) + num_chars * 2, 0, 2)
}
return wstr
}
} $else {
srunes := _str.runes()
unsafe {
mut result := &u16(vcalloc_noscan((srunes.len + 1) * 2))
for i, r in srunes {
result[i] = u16(r)
}
result[srunes.len] = 0
return result
}
}
}
// string_from_wide creates a V string, encoded in UTF-8, given a windows
// style string encoded in UTF-16. Note that this function first searches
// for the string terminator 0 character, and is thus slower, while more
// convenient compared to string_from_wide2/2 (you have to know the length
// in advance to use string_from_wide2/2).
// See also builtin.wchar.to_string/1, for a version that eases working with
// the platform dependent &wchar_t L"" strings.
[manualfree; unsafe]
pub fn string_from_wide(_wstr &u16) string {
$if windows {
unsafe {
wstr_len := C.wcslen(_wstr)
return string_from_wide2(_wstr, int(wstr_len))
}
} $else {
mut i := 0
for unsafe { _wstr[i] } != 0 {
i++
}
return unsafe { string_from_wide2(_wstr, i) }
}
}
// string_from_wide2 creates a V string, encoded in UTF-8, given a windows
// style string, encoded in UTF-16. It is more efficient, compared to
// string_from_wide, but it requires you to know the input string length,
// and to pass it as the second argument.
// See also builtin.wchar.to_string2/2, for a version that eases working
// with the platform dependent &wchar_t L"" strings.
[manualfree; unsafe]
pub fn string_from_wide2(_wstr &u16, len int) string {
$if windows {
unsafe {
num_chars := C.WideCharToMultiByte(cp_utf8, 0, _wstr, len, 0, 0, 0, 0)
mut str_to := malloc_noscan(num_chars + 1)
if str_to != 0 {
C.WideCharToMultiByte(cp_utf8, 0, _wstr, len, &char(str_to), num_chars,
0, 0)
C.memset(str_to + num_chars, 0, 1)
}
return tos2(str_to)
}
} $else {
mut sb := strings.new_builder(len)
defer {
unsafe { sb.free() }
}
for i := 0; i < len; i++ {
u := unsafe { rune(_wstr[i]) }
sb.write_rune(u)
}
res := sb.str()
return res
}
}