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