428 lines
16 KiB
C++
428 lines
16 KiB
C++
//
|
|
// Copyright (c) 2015 Artyom Beilis (Tonkikh)
|
|
// Copyright (c) 2020 Alexander Grund
|
|
//
|
|
// Distributed under the Boost Software License, Version 1.0. (See
|
|
// accompanying file LICENSE or copy at
|
|
// http://www.boost.org/LICENSE_1_0.txt)
|
|
//
|
|
#ifndef BOOST_NOWIDE_UTF8_CODECVT_HPP_INCLUDED
|
|
#define BOOST_NOWIDE_UTF8_CODECVT_HPP_INCLUDED
|
|
|
|
#include <boost/nowide/replacement.hpp>
|
|
#include <boost/nowide/utf/utf.hpp>
|
|
#include <cstdint>
|
|
#include <locale>
|
|
|
|
namespace boost {
|
|
namespace nowide {
|
|
|
|
static_assert(sizeof(std::mbstate_t) >= 2, "mbstate_t is to small to store an UTF-16 codepoint");
|
|
namespace detail {
|
|
// Avoid including cstring for std::memcpy
|
|
inline void copy_uint16_t(void* dst, const void* src)
|
|
{
|
|
unsigned char* cdst = static_cast<unsigned char*>(dst);
|
|
const unsigned char* csrc = static_cast<const unsigned char*>(src);
|
|
cdst[0] = csrc[0];
|
|
cdst[1] = csrc[1];
|
|
}
|
|
inline std::uint16_t read_state(const std::mbstate_t& src)
|
|
{
|
|
std::uint16_t dst;
|
|
copy_uint16_t(&dst, &src);
|
|
return dst;
|
|
}
|
|
inline void write_state(std::mbstate_t& dst, const std::uint16_t src)
|
|
{
|
|
copy_uint16_t(&dst, &src);
|
|
}
|
|
} // namespace detail
|
|
|
|
#if defined _MSC_VER && _MSC_VER < 1700
|
|
// MSVC do_length is non-standard it counts wide characters instead of narrow and does not change mbstate
|
|
#define BOOST_NOWIDE_DO_LENGTH_MBSTATE_CONST
|
|
#endif
|
|
|
|
/// std::codecvt implementation that converts between UTF-8 and UTF-16 or UTF-32
|
|
///
|
|
/// @tparam CharSize Determines the encoding: 2 for UTF-16, 4 for UTF-32
|
|
///
|
|
/// Invalid sequences are replaced by #BOOST_NOWIDE_REPLACEMENT_CHARACTER
|
|
/// A trailing incomplete sequence will result in a return value of std::codecvt::partial
|
|
template<typename CharType, int CharSize = sizeof(CharType)>
|
|
class utf8_codecvt;
|
|
|
|
/// Specialization for the UTF-8 <-> UTF-16 variant of the std::codecvt implementation
|
|
template<typename CharType>
|
|
class BOOST_SYMBOL_VISIBLE utf8_codecvt<CharType, 2> : public std::codecvt<CharType, char, std::mbstate_t>
|
|
{
|
|
public:
|
|
static_assert(sizeof(CharType) >= 2, "CharType must be able to store UTF16 code point");
|
|
|
|
utf8_codecvt(size_t refs = 0) : std::codecvt<CharType, char, std::mbstate_t>(refs)
|
|
{}
|
|
|
|
protected:
|
|
using uchar = CharType;
|
|
|
|
std::codecvt_base::result do_unshift(std::mbstate_t& s, char* from, char* /*to*/, char*& next) const override
|
|
{
|
|
if(detail::read_state(s) != 0)
|
|
return std::codecvt_base::error;
|
|
next = from;
|
|
return std::codecvt_base::ok;
|
|
}
|
|
int do_encoding() const noexcept override
|
|
{
|
|
return 0;
|
|
}
|
|
int do_max_length() const noexcept override
|
|
{
|
|
return 4;
|
|
}
|
|
bool do_always_noconv() const noexcept override
|
|
{
|
|
return false;
|
|
}
|
|
|
|
int do_length(std::mbstate_t
|
|
#ifdef BOOST_NOWIDE_DO_LENGTH_MBSTATE_CONST
|
|
const
|
|
#endif
|
|
& std_state,
|
|
const char* from,
|
|
const char* from_end,
|
|
size_t max) const override
|
|
{
|
|
std::uint16_t state = detail::read_state(std_state);
|
|
#ifndef BOOST_NOWIDE_DO_LENGTH_MBSTATE_CONST
|
|
const char* save_from = from;
|
|
#else
|
|
size_t save_max = max;
|
|
#endif
|
|
while(max > 0 && from < from_end)
|
|
{
|
|
const char* prev_from = from;
|
|
std::uint32_t ch = utf::utf_traits<char>::decode(from, from_end);
|
|
if(ch == utf::illegal)
|
|
{
|
|
ch = BOOST_NOWIDE_REPLACEMENT_CHARACTER;
|
|
} else if(ch == utf::incomplete)
|
|
{
|
|
from = prev_from;
|
|
break;
|
|
}
|
|
max--;
|
|
if(ch > 0xFFFF)
|
|
{
|
|
if(state == 0)
|
|
{
|
|
from = prev_from;
|
|
state = 1;
|
|
} else
|
|
{
|
|
state = 0;
|
|
}
|
|
}
|
|
}
|
|
#ifndef BOOST_NOWIDE_DO_LENGTH_MBSTATE_CONST
|
|
detail::write_state(std_state, state);
|
|
return static_cast<int>(from - save_from);
|
|
#else
|
|
return static_cast<int>(save_max - max);
|
|
#endif
|
|
}
|
|
|
|
std::codecvt_base::result do_in(std::mbstate_t& std_state,
|
|
const char* from,
|
|
const char* from_end,
|
|
const char*& from_next,
|
|
uchar* to,
|
|
uchar* to_end,
|
|
uchar*& to_next) const override
|
|
{
|
|
std::codecvt_base::result r = std::codecvt_base::ok;
|
|
|
|
// mbstate_t is POD type and should be initialized to 0 (i.a. state = stateT())
|
|
// according to standard. We use it to keep a flag 0/1 for surrogate pair writing
|
|
//
|
|
// if 0 no code above >0xFFFF observed, of 1 a code above 0xFFFF observed
|
|
// and first pair is written, but no input consumed
|
|
std::uint16_t state = detail::read_state(std_state);
|
|
while(to < to_end && from < from_end)
|
|
{
|
|
const char* from_saved = from;
|
|
|
|
uint32_t ch = utf::utf_traits<char>::decode(from, from_end);
|
|
|
|
if(ch == utf::illegal)
|
|
{
|
|
ch = BOOST_NOWIDE_REPLACEMENT_CHARACTER;
|
|
} else if(ch == utf::incomplete)
|
|
{
|
|
from = from_saved;
|
|
r = std::codecvt_base::partial;
|
|
break;
|
|
}
|
|
// Normal codepoints go directly to stream
|
|
if(ch <= 0xFFFF)
|
|
{
|
|
*to++ = static_cast<CharType>(ch);
|
|
} else
|
|
{
|
|
// for other codepoints we do following
|
|
//
|
|
// 1. We can't consume our input as we may find ourself
|
|
// in state where all input consumed but not all output written,i.e. only
|
|
// 1st pair is written
|
|
// 2. We only write first pair and mark this in the state, we also revert back
|
|
// the from pointer in order to make sure this codepoint would be read
|
|
// once again and then we would consume our input together with writing
|
|
// second surrogate pair
|
|
ch -= 0x10000;
|
|
std::uint16_t vh = static_cast<std::uint16_t>(ch >> 10);
|
|
std::uint16_t vl = ch & 0x3FF;
|
|
std::uint16_t w1 = vh + 0xD800;
|
|
std::uint16_t w2 = vl + 0xDC00;
|
|
if(state == 0)
|
|
{
|
|
from = from_saved;
|
|
*to++ = static_cast<CharType>(w1);
|
|
state = 1;
|
|
} else
|
|
{
|
|
*to++ = static_cast<CharType>(w2);
|
|
state = 0;
|
|
}
|
|
}
|
|
}
|
|
from_next = from;
|
|
to_next = to;
|
|
if(r == std::codecvt_base::ok && (from != from_end || state != 0))
|
|
r = std::codecvt_base::partial;
|
|
detail::write_state(std_state, state);
|
|
return r;
|
|
}
|
|
|
|
std::codecvt_base::result do_out(std::mbstate_t& std_state,
|
|
const uchar* from,
|
|
const uchar* from_end,
|
|
const uchar*& from_next,
|
|
char* to,
|
|
char* to_end,
|
|
char*& to_next) const override
|
|
{
|
|
std::codecvt_base::result r = std::codecvt_base::ok;
|
|
// mbstate_t is POD type and should be initialized to 0 (i.a. state = stateT())
|
|
// according to standard. We assume that sizeof(mbstate_t) >=2 in order
|
|
// to be able to store first observed surrogate pair
|
|
//
|
|
// State: state!=0 - a first surrogate pair was observed (state = first pair),
|
|
// we expect the second one to come and then zero the state
|
|
///
|
|
std::uint16_t state = detail::read_state(std_state);
|
|
while(to < to_end && from < from_end)
|
|
{
|
|
std::uint32_t ch = 0;
|
|
if(state != 0)
|
|
{
|
|
// if the state indicates that 1st surrogate pair was written
|
|
// we should make sure that the second one that comes is actually
|
|
// second surrogate
|
|
std::uint16_t w1 = state;
|
|
std::uint16_t w2 = *from;
|
|
// we don't forward from as writing may fail to incomplete or
|
|
// partial conversion
|
|
if(0xDC00 <= w2 && w2 <= 0xDFFF)
|
|
{
|
|
std::uint16_t vh = w1 - 0xD800;
|
|
std::uint16_t vl = w2 - 0xDC00;
|
|
ch = ((uint32_t(vh) << 10) | vl) + 0x10000;
|
|
} else
|
|
{
|
|
ch = BOOST_NOWIDE_REPLACEMENT_CHARACTER;
|
|
}
|
|
} else
|
|
{
|
|
ch = *from;
|
|
if(0xD800 <= ch && ch <= 0xDBFF)
|
|
{
|
|
// if this is a first surrogate pair we put
|
|
// it into the state and consume it, note we don't
|
|
// go forward as it should be illegal so we increase
|
|
// the from pointer manually
|
|
state = static_cast<std::uint16_t>(ch);
|
|
from++;
|
|
continue;
|
|
} else if(0xDC00 <= ch && ch <= 0xDFFF)
|
|
{
|
|
// if we observe second surrogate pair and
|
|
// first only may be expected we should break from the loop with error
|
|
// as it is illegal input
|
|
ch = BOOST_NOWIDE_REPLACEMENT_CHARACTER;
|
|
}
|
|
}
|
|
if(!utf::is_valid_codepoint(ch))
|
|
{
|
|
r = std::codecvt_base::error;
|
|
break;
|
|
}
|
|
int len = utf::utf_traits<char>::width(ch);
|
|
if(to_end - to < len)
|
|
{
|
|
r = std::codecvt_base::partial;
|
|
break;
|
|
}
|
|
to = utf::utf_traits<char>::encode(ch, to);
|
|
state = 0;
|
|
from++;
|
|
}
|
|
from_next = from;
|
|
to_next = to;
|
|
if(r == std::codecvt_base::ok && (from != from_end || state != 0))
|
|
r = std::codecvt_base::partial;
|
|
detail::write_state(std_state, state);
|
|
return r;
|
|
}
|
|
};
|
|
|
|
/// Specialization for the UTF-8 <-> UTF-32 variant of the std::codecvt implementation
|
|
template<typename CharType>
|
|
class BOOST_SYMBOL_VISIBLE utf8_codecvt<CharType, 4> : public std::codecvt<CharType, char, std::mbstate_t>
|
|
{
|
|
public:
|
|
utf8_codecvt(size_t refs = 0) : std::codecvt<CharType, char, std::mbstate_t>(refs)
|
|
{}
|
|
|
|
protected:
|
|
using uchar = CharType;
|
|
|
|
std::codecvt_base::result
|
|
do_unshift(std::mbstate_t& /*s*/, char* from, char* /*to*/, char*& next) const override
|
|
{
|
|
next = from;
|
|
return std::codecvt_base::ok;
|
|
}
|
|
int do_encoding() const noexcept override
|
|
{
|
|
return 0;
|
|
}
|
|
int do_max_length() const noexcept override
|
|
{
|
|
return 4;
|
|
}
|
|
bool do_always_noconv() const noexcept override
|
|
{
|
|
return false;
|
|
}
|
|
|
|
int do_length(std::mbstate_t
|
|
#ifdef BOOST_NOWIDE_DO_LENGTH_MBSTATE_CONST
|
|
const
|
|
#endif
|
|
& /*state*/,
|
|
const char* from,
|
|
const char* from_end,
|
|
size_t max) const override
|
|
{
|
|
#ifndef BOOST_NOWIDE_DO_LENGTH_MBSTATE_CONST
|
|
const char* start_from = from;
|
|
#else
|
|
size_t save_max = max;
|
|
#endif
|
|
|
|
while(max > 0 && from < from_end)
|
|
{
|
|
const char* save_from = from;
|
|
std::uint32_t ch = utf::utf_traits<char>::decode(from, from_end);
|
|
if(ch == utf::incomplete)
|
|
{
|
|
from = save_from;
|
|
break;
|
|
} else if(ch == utf::illegal)
|
|
{
|
|
ch = BOOST_NOWIDE_REPLACEMENT_CHARACTER;
|
|
}
|
|
max--;
|
|
}
|
|
#ifndef BOOST_NOWIDE_DO_LENGTH_MBSTATE_CONST
|
|
return from - start_from;
|
|
#else
|
|
return save_max - max;
|
|
#endif
|
|
}
|
|
|
|
std::codecvt_base::result do_in(std::mbstate_t& /*state*/,
|
|
const char* from,
|
|
const char* from_end,
|
|
const char*& from_next,
|
|
uchar* to,
|
|
uchar* to_end,
|
|
uchar*& to_next) const override
|
|
{
|
|
std::codecvt_base::result r = std::codecvt_base::ok;
|
|
|
|
while(to < to_end && from < from_end)
|
|
{
|
|
const char* from_saved = from;
|
|
|
|
uint32_t ch = utf::utf_traits<char>::decode(from, from_end);
|
|
|
|
if(ch == utf::illegal)
|
|
{
|
|
ch = BOOST_NOWIDE_REPLACEMENT_CHARACTER;
|
|
} else if(ch == utf::incomplete)
|
|
{
|
|
r = std::codecvt_base::partial;
|
|
from = from_saved;
|
|
break;
|
|
}
|
|
*to++ = ch;
|
|
}
|
|
from_next = from;
|
|
to_next = to;
|
|
if(r == std::codecvt_base::ok && from != from_end)
|
|
r = std::codecvt_base::partial;
|
|
return r;
|
|
}
|
|
|
|
std::codecvt_base::result do_out(std::mbstate_t& /*std_state*/,
|
|
const uchar* from,
|
|
const uchar* from_end,
|
|
const uchar*& from_next,
|
|
char* to,
|
|
char* to_end,
|
|
char*& to_next) const override
|
|
{
|
|
std::codecvt_base::result r = std::codecvt_base::ok;
|
|
while(to < to_end && from < from_end)
|
|
{
|
|
std::uint32_t ch = 0;
|
|
ch = *from;
|
|
if(!utf::is_valid_codepoint(ch))
|
|
{
|
|
ch = BOOST_NOWIDE_REPLACEMENT_CHARACTER;
|
|
}
|
|
int len = utf::utf_traits<char>::width(ch);
|
|
if(to_end - to < len)
|
|
{
|
|
r = std::codecvt_base::partial;
|
|
break;
|
|
}
|
|
to = utf::utf_traits<char>::encode(ch, to);
|
|
from++;
|
|
}
|
|
from_next = from;
|
|
to_next = to;
|
|
if(r == std::codecvt_base::ok && from != from_end)
|
|
r = std::codecvt_base::partial;
|
|
return r;
|
|
}
|
|
};
|
|
|
|
} // namespace nowide
|
|
} // namespace boost
|
|
|
|
#endif
|