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#pragma once
#include "string_view.hpp"
#include <array>
#include <cstring>
namespace sol {
// Everything here was lifted pretty much straight out of
// ogonek, because fuck figuring it out=
namespace unicode {
enum class error_code {
ok = 0,
invalid_code_point,
invalid_code_unit,
invalid_leading_surrogate,
invalid_trailing_surrogate,
sequence_too_short,
overlong_sequence,
};
inline const string_view& to_string(error_code ec) {
static const string_view storage[7] = {
"ok",
"invalid code points",
"invalid code unit",
"invalid leading surrogate",
"invalid trailing surrogate",
"sequence too short",
"overlong sequence"
};
return storage[static_cast<std::size_t>(ec)];
}
template <typename It>
struct decoded_result {
error_code error;
char32_t codepoint;
It next;
};
template <typename C>
struct encoded_result {
error_code error;
std::size_t code_units_size;
std::array<C, 4> code_units;
};
struct unicode_detail {
// codepoint related
static constexpr char32_t last_code_point = 0x10FFFF;
static constexpr char32_t first_lead_surrogate = 0xD800;
static constexpr char32_t last_lead_surrogate = 0xDBFF;
static constexpr char32_t first_trail_surrogate = 0xDC00;
static constexpr char32_t last_trail_surrogate = 0xDFFF;
static constexpr char32_t first_surrogate = first_lead_surrogate;
static constexpr char32_t last_surrogate = last_trail_surrogate;
static constexpr bool is_lead_surrogate(char32_t u) {
return u >= first_lead_surrogate && u <= last_lead_surrogate;
}
static constexpr bool is_trail_surrogate(char32_t u) {
return u >= first_trail_surrogate && u <= last_trail_surrogate;
}
static constexpr bool is_surrogate(char32_t u) {
return u >= first_surrogate && u <= last_surrogate;
}
// utf8 related
static constexpr auto last_1byte_value = 0x7Fu;
static constexpr auto last_2byte_value = 0x7FFu;
static constexpr auto last_3byte_value = 0xFFFFu;
static constexpr auto start_2byte_mask = 0x80u;
static constexpr auto start_3byte_mask = 0xE0u;
static constexpr auto start_4byte_mask = 0xF0u;
static constexpr auto continuation_mask = 0xC0u;
static constexpr auto continuation_signature = 0x80u;
static constexpr bool is_invalid(unsigned char b) {
return b == 0xC0 || b == 0xC1 || b > 0xF4;
}
static constexpr bool is_continuation(unsigned char b) {
return (b & unicode_detail::continuation_mask) == unicode_detail::continuation_signature;
}
static constexpr bool is_overlong(char32_t u, std::size_t bytes) {
return u <= unicode_detail::last_1byte_value || (u <= unicode_detail::last_2byte_value && bytes > 2)
|| (u <= unicode_detail::last_3byte_value && bytes > 3);
}
static constexpr int sequence_length(unsigned char b) {
return (b & start_2byte_mask) == 0 ? 1
: (b & start_3byte_mask) != start_3byte_mask ? 2
: (b & start_4byte_mask) != start_4byte_mask ? 3
: 4;
}
static constexpr char32_t decode(unsigned char b0, unsigned char b1) {
return ((b0 & 0x1F) << 6) | (b1 & 0x3F);
}
static constexpr char32_t decode(unsigned char b0, unsigned char b1, unsigned char b2) {
return ((b0 & 0x0F) << 12) | ((b1 & 0x3F) << 6) | (b2 & 0x3F);
}
static constexpr char32_t decode(unsigned char b0, unsigned char b1, unsigned char b2, unsigned char b3) {
return ((b0 & 0x07) << 18) | ((b1 & 0x3F) << 12) | ((b2 & 0x3F) << 6) | (b3 & 0x3F);
}
// utf16 related
static constexpr char32_t last_bmp_value = 0xFFFF;
static constexpr char32_t normalizing_value = 0x10000;
static constexpr int lead_surrogate_bitmask = 0xFFC00;
static constexpr int trail_surrogate_bitmask = 0x3FF;
static constexpr int lead_shifted_bits = 10;
static constexpr char32_t replacement = 0xFFFD;
static char32_t combine_surrogates(char16_t lead, char16_t trail) {
auto hi = lead - first_lead_surrogate;
auto lo = trail - first_trail_surrogate;
return normalizing_value + ((hi << lead_shifted_bits) | lo);
}
};
inline encoded_result<char> code_point_to_utf8(char32_t codepoint) {
encoded_result<char> er;
er.error = error_code::ok;
if (codepoint <= unicode_detail::last_1byte_value) {
er.code_units_size = 1;
er.code_units = std::array<char, 4>{ { static_cast<char>(codepoint) } };
}
else if (codepoint <= unicode_detail::last_2byte_value) {
er.code_units_size = 2;
er.code_units = std::array<char, 4>{{
static_cast<char>(0xC0 | ((codepoint & 0x7C0) >> 6)),
static_cast<char>(0x80 | (codepoint & 0x3F)),
}};
}
else if (codepoint <= unicode_detail::last_3byte_value) {
er.code_units_size = 3;
er.code_units = std::array<char, 4>{{
static_cast<char>(0xE0 | ((codepoint & 0xF000) >> 12)),
static_cast<char>(0x80 | ((codepoint & 0xFC0) >> 6)),
static_cast<char>(0x80 | (codepoint & 0x3F)),
}};
}
else {
er.code_units_size = 4;
er.code_units = std::array<char, 4>{ {
static_cast<char>(0xF0 | ((codepoint & 0x1C0000) >> 18)),
static_cast<char>(0x80 | ((codepoint & 0x3F000) >> 12)),
static_cast<char>(0x80 | ((codepoint & 0xFC0) >> 6)),
static_cast<char>(0x80 | (codepoint & 0x3F)),
} };
}
return er;
}
inline encoded_result<char16_t> code_point_to_utf16(char32_t codepoint) {
encoded_result<char16_t> er;
if (codepoint <= unicode_detail::last_bmp_value) {
er.code_units_size = 1;
er.code_units = std::array<char16_t, 4>{ { static_cast<char16_t>(codepoint) } };
er.error = error_code::ok;
}
else {
auto normal = codepoint - unicode_detail::normalizing_value;
auto lead = unicode_detail::first_lead_surrogate + ((normal & unicode_detail::lead_surrogate_bitmask) >> unicode_detail::lead_shifted_bits);
auto trail = unicode_detail::first_trail_surrogate + (normal & unicode_detail::trail_surrogate_bitmask);
er.code_units = std::array<char16_t, 4>{ {
static_cast<char16_t>(lead),
static_cast<char16_t>(trail)
} };
er.code_units_size = 2;
er.error = error_code::ok;
}
return er;
}
inline encoded_result<char32_t> code_point_to_utf32(char32_t codepoint) {
encoded_result<char32_t> er;
er.code_units_size = 1;
er.code_units[0] = codepoint;
er.error = error_code::ok;
return er;
}
template <typename It>
inline decoded_result<It> utf8_to_code_point(It it, It last) {
decoded_result<It> dr;
if (it == last) {
dr.next = it;
dr.error = error_code::sequence_too_short;
return dr;
}
unsigned char b0 = *it;
std::size_t length = unicode_detail::sequence_length(b0);
if (length == 1) {
dr.codepoint = static_cast<char32_t>(b0);
dr.error = error_code::ok;
++it;
dr.next = it;
return dr;
}
if (unicode_detail::is_invalid(b0) || unicode_detail::is_continuation(b0)) {
dr.error = error_code::invalid_code_unit;
dr.next = it;
return dr;
}
++it;
std::array<unsigned char, 4> b;
b[0] = b0;
for (std::size_t i = 1; i < length; ++i) {
b[i] = *it;
if (!unicode_detail::is_continuation(b[i])) {
dr.error = error_code::invalid_code_unit;
dr.next = it;
return dr;
}
++it;
}
char32_t decoded;
switch (length) {
case 2:
decoded = unicode_detail::decode(b[0], b[1]);
break;
case 3:
decoded = unicode_detail::decode(b[0], b[1], b[2]);
break;
default:
decoded = unicode_detail::decode(b[0], b[1], b[2], b[3]);
break;
}
if (unicode_detail::is_overlong(decoded, length)) {
dr.error = error_code::overlong_sequence;
return dr;
}
if (unicode_detail::is_surrogate(decoded) || decoded > unicode_detail::last_code_point) {
dr.error = error_code::invalid_code_point;
return dr;
}
// then everything is fine
dr.codepoint = decoded;
dr.error = error_code::ok;
dr.next = it;
return dr;
}
template <typename It>
inline decoded_result<It> utf16_to_code_point(It it, It last) {
decoded_result<It> dr;
if (it == last) {
dr.next = it;
dr.error = error_code::sequence_too_short;
return dr;
}
char16_t lead = static_cast<char16_t>(*it);
if (!unicode_detail::is_surrogate(lead)) {
++it;
dr.codepoint = static_cast<char32_t>(lead);
dr.next = it;
dr.error = error_code::ok;
return dr;
}
if (!unicode_detail::is_lead_surrogate(lead)) {
dr.error = error_code::invalid_leading_surrogate;
dr.next = it;
return dr;
}
++it;
auto trail = *it;
if (!unicode_detail::is_trail_surrogate(trail)) {
dr.error = error_code::invalid_trailing_surrogate;
dr.next = it;
return dr;
}
dr.codepoint = unicode_detail::combine_surrogates(lead, trail);
dr.next = ++it;
dr.error = error_code::ok;
return dr;
}
template <typename It>
inline decoded_result<It> utf32_to_code_point(It it, It last) {
decoded_result<It> dr;
if (it == last) {
dr.next = it;
dr.error = error_code::sequence_too_short;
return dr;
}
dr.codepoint = static_cast<char32_t>(*it);
dr.next = ++it;
dr.error = error_code::ok;
return dr;
}
}
}
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