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81 lines
2.1 KiB
81 lines
2.1 KiB
#include "utils/utf8.hpp" |
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#include <cstddef> |
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#include <cstdint> |
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#include <cstring> |
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#include <hoehrmann_utf8.h> |
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#include "utils/attributes.h" |
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namespace devilution { |
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namespace { |
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/** Truncates `str` to at most `len` at a code point boundary. */ |
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std::string_view TruncateUtf8(std::string_view str, std::size_t len) |
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{ |
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if (str.size() > len) { |
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std::size_t truncIndex = len; |
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while (truncIndex > 0 && IsTrailUtf8CodeUnit(str[truncIndex])) |
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truncIndex--; |
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str.remove_suffix(str.size() - truncIndex); |
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} |
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return str; |
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} |
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} // namespace |
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char32_t DecodeFirstUtf8CodePoint(std::string_view input, std::size_t *len) |
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{ |
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uint32_t codepoint = 0; |
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uint8_t state = UTF8_ACCEPT; |
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for (std::size_t i = 0; i < input.size(); ++i) { |
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state = utf8_decode_step(state, static_cast<uint8_t>(input[i]), &codepoint); |
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if (state == UTF8_ACCEPT) { |
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*len = i + 1; |
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return codepoint; |
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} |
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if (state == UTF8_REJECT) { |
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*len = i + 1; |
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return Utf8DecodeError; |
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} |
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} |
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*len = input.size(); |
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return Utf8DecodeError; |
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} |
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void CopyUtf8(char *dest, std::string_view source, std::size_t bytes) |
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{ |
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source = TruncateUtf8(source, bytes - 1); |
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std::memcpy(dest, source.data(), source.size()); |
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dest[source.size()] = '\0'; |
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} |
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void AppendUtf8(char32_t codepoint, std::string &out) |
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{ |
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if (codepoint <= 0x7F) { |
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out += static_cast<char>(codepoint); |
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return; |
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} |
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char buf[4]; |
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if (codepoint <= 0x7FF) { |
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buf[0] = static_cast<char>(0xC0 | (codepoint >> 6 & 0x3F)); |
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buf[1] = static_cast<char>(0x80 | (codepoint & 0x3F)); |
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out.append(buf, 2); |
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} else if (codepoint <= 0xFFFF) { |
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buf[0] = static_cast<char>(0xE0 | (codepoint >> 12 & 0x3F)); |
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buf[1] = static_cast<char>(0x80 | (codepoint >> 6 & 0x3F)); |
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buf[2] = static_cast<char>(0x80 | (codepoint & 0x3F)); |
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out.append(buf, 3); |
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} else { |
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buf[0] = static_cast<char>(0xF0 | (codepoint >> 18 & 0x3F)); |
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buf[1] = static_cast<char>(0x80 | (codepoint >> 12 & 0x3F)); |
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buf[2] = static_cast<char>(0x80 | (codepoint >> 6 & 0x3F)); |
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buf[3] = static_cast<char>(0x80 | (codepoint & 0x3F)); |
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out.append(buf, 4); |
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} |
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} |
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} // namespace devilution
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