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#pragma once
namespace nall {
//note: this function assumes the string contains valid UTF-8 characters
//invalid characters will result in an incorrect result from this function
//invalid case 1: byte 1 == 0b'01xxxxxx
//invalid case 2: bytes 2-4 != 0b'10xxxxxx
//invalid case 3: end of string without bytes 2-4 present
inline auto characters(string_view self, s32 offset, s32 length) -> u32 {
u32 characters = 0;
if(offset < 0) offset = self.size() - abs(offset);
if(offset >= 0 && offset < self.size()) {
if(length < 0) length = self.size() - offset;
if(length >= 0) {
for(s32 index = offset; index < offset + length;) {
auto byte = self.data()[index++];
if((byte & 0b111'00000) == 0b110'00000) index += 1;
if((byte & 0b1111'0000) == 0b1110'0000) index += 2;
if((byte & 0b11111'000) == 0b11110'000) index += 3;
characters++;
}
}
}
return characters;
}
inline auto string::characters(s32 offset, s32 length) const -> u32 {
return nall::characters(*this, offset, length);
}
}
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