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v/vlib/builtin/rune.v

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// Copyright (c) 2019-2022 Alexander Medvednikov. All rights reserved.
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// Use of this source code is governed by an MIT license that can be found in the LICENSE file.
module builtin
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import strings
// This was never working correctly, the issue is now
// fixed however the type checks in checker need to be
// updated. if you uncomment it you will see the issue
// type rune = int
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pub fn (c rune) str() string {
return utf32_to_str(u32(c))
/*
unsafe {
fst_byte := int(c)>>8 * 3 & 0xff
len := utf8_char_len(byte(fst_byte))
println('len=$len')
mut str := string{
len: len
str: malloc_noscan(len + 1)
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}
for i in 0..len {
str.str[i] = byte(int(c)>>8 * (3 - i) & 0xff)
}
str.str[len] = `\0`
println(str)
return str
}
*/
}
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// string converts a rune array to a string
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[manualfree]
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pub fn (ra []rune) string() string {
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mut sb := strings.new_builder(ra.len)
sb.write_runes(ra)
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res := sb.str()
unsafe { sb.free() }
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return res
}
// repeat returns a new string with `count` number of copies of the rune it was called on.
pub fn (c rune) repeat(count int) string {
if count < 0 {
panic('rune.repeat: count is negative: $count')
} else if count == 0 {
return ''
} else if count == 1 {
return c.str()
}
mut buffer := [5]byte{}
res := unsafe { utf32_to_str_no_malloc(u32(c), &buffer[0]) }
return res.repeat(count)
}
[manualfree]
pub fn (c rune) bytes() []byte {
mut res := []byte{cap: 5}
res.len = unsafe { utf32_decode_to_buffer(u32(c), &byte(res.data)) }
return res
}
// length_in_bytes returns the number of bytes needed to store the code point.
// Returns -1 if the data is not a valid code point.
pub fn (c rune) length_in_bytes() int {
code := u32(c)
if code <= 0x7F {
return 1
} else if code <= 0x7FF {
return 2
} else if 0xD800 <= code && code <= 0xDFFF {
// between min and max for surrogates
return -1
} else if code <= 0xFFFF {
return 3
} else if code <= 0x10FFFF {
// 0x10FFFF is the maximum valid unicode code point
return 4
}
return -1
}