//
// Copyright (c) 2015 Artyom Beilis (Tonkikh)
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
#ifndef BOOST_LOCALE_GENERIC_CODECVT_HPP
#define BOOST_LOCALE_GENERIC_CODECVT_HPP
#include <boost/locale/utf.hpp>
#include <boost/cstdint.hpp>
#include <boost/static_assert.hpp>
#include <locale>
namespace boost {
namespace locale {
#ifndef BOOST_LOCALE_DOXYGEN
//
// Make sure that mbstate can keep 16 bit of UTF-16 sequence
//
BOOST_STATIC_ASSERT(sizeof(std::mbstate_t)>=2);
#endif
#if defined(_MSC_VER) && _MSC_VER < 1700
// up to MSVC 11 (2012) do_length is non-standard it counts wide characters instead of narrow and does not change mbstate
#define BOOST_LOCALE_DO_LENGTH_MBSTATE_CONST
#endif
///
/// \brief A base class that used to define constants for generic_codecvt
///
class generic_codecvt_base {
public:
///
/// Initail state for converting to or from unicode code points, used by initial_state in derived classes
///
enum initial_convertion_state {
to_unicode_state, ///< The state would be used by to_unicode functions
from_unicode_state ///< The state would be used by from_unicode functions
};
};
///
/// \brief Geneneric generic codecvt facet, various stateless encodings to UTF-16 and UTF-32 using wchar_t, char32_t and char16_t
///
/// Implementations should dervide from this class defining itself as CodecvtImpl and provide following members
///
/// - `state_type` - a type of special object that allows to store intermediate cached data, for example `iconv_t` descriptor
/// - `state_type initial_state(generic_codecvt_base::initial_convertion_state direction) const` - member function that creates initial state
/// - `int max_encoding_length() const` - a maximal length that one Unicode code point is represented, for UTF-8 for example it is 4 from ISO-8859-1 it is 1
/// - `utf::code_point to_unicode(state_type &state,char const *&begin,char const *end)` - extract first code point from the text in range [begin,end), in case of success begin would point to the next character sequence to be encoded to next code point, in case of incomplete sequence - utf::incomplete shell be returned, and in case of invalid input sequence utf::illegal shell be returned and begin would remain unmodified
/// - `utf::code_point from_unicode(state_type &state,utf::code_point u,char *begin,char const *end)` - convert a unicode code point `u` into a character seqnece at [begin,end). Return the length of the sequence in case of success, utf::incomplete in case of not enough room to encode the code point of utf::illegal in case conversion can not be performed
///
///
/// For example implementaion of codecvt for latin1/ISO-8859-1 character set
///
/// \code
///
/// template<typename CharType>
/// class latin1_codecvt :boost::locale::generic_codecvt<CharType,latin1_codecvt<CharType> >
/// {
/// public:
///
/// /* Standard codecvt constructor */
/// latin1_codecvt(size_t refs = 0) : boost::locale::generic_codecvt<CharType,latin1_codecvt<CharType> >(refs)
/// {
/// }
///
/// /* State is unused but required by generic_codecvt */
/// struct state_type {};
///
/// state_type initial_state(generic_codecvt_base::initial_convertion_state /*unused*/) const
/// {
/// return state_type();
/// }
///
/// int max_encoding_length() const
/// {
/// return 1;
/// }
///
/// boost::locale::utf::code_point to_unicode(state_type &,char const *&begin,char const *end) const
/// {
/// if(begin == end)
/// return boost::locale::utf::incomplete;
/// return *begin++;
/// }
///
/// boost::locale::utf::code_point from_unicode(state_type &,boost::locale::utf::code_point u,char *begin,char const *end) const
/// {
/// if(u >= 256)
/// return boost::locale::utf::illegal;
/// if(begin == end)
/// return boost::locale::utf::incomplete;
/// *begin = u;
/// return 1;
/// }
/// };
///
/// \endcode
///
/// When external tools used for encoding conversion, the `state_type` is useful to save objects used for conversions. For example,
/// icu::UConverter can be saved in such a state for an efficient use:
///
/// \code
/// template<typename CharType>
/// class icu_codecvt :boost::locale::generic_codecvt<CharType,icu_codecvt<CharType> >
/// {
/// public:
///
/// /* Standard codecvt constructor */
/// icu_codecvt(std::string const &name,refs = 0) :
/// boost::locale::generic_codecvt<CharType,latin1_codecvt<CharType> >(refs)
/// { ... }
///
/// /* State is unused but required by generic_codecvt */
/// struct std::unique_ptr<UConverter,void (*)(UConverter*)> state_type;
///
/// state_type &&initial_state(generic_codecvt_base::initial_convertion_state /*unused*/) const
/// {
/// UErrorCode err = U_ZERO_ERROR;
/// state_type ptr(ucnv_safeClone(converter_,0,0,&err,ucnv_close);
/// return std::move(ptr);
/// }
///
/// boost::locale::utf::code_point to_unicode(state_type &ptr,char const *&begin,char const *end) const
/// {
/// UErrorCode err = U_ZERO_ERROR;
/// boost::locale::utf::code_point cp = ucnv_getNextUChar(ptr.get(),&begin,end,&err);
/// ...
/// }
/// ...
/// };
/// \endcode
///
///
template<typename CharType,typename CodecvtImpl,int CharSize=sizeof(CharType)>
class generic_codecvt;
///
/// \brief UTF-16 to/from UTF-8 codecvt facet to use with char16_t or wchar_t on Windows
///
/// Note in order to fit the requirements of usability by std::wfstream it uses mbstate_t
/// to handle intermediate states in handling of variable length UTF-16 sequences
///
/// Its member functions implement standard virtual functions of basic codecvt
///
template<typename CharType,typename CodecvtImpl>
class generic_codecvt<CharType,CodecvtImpl,2> : public std::codecvt<CharType,char,std::mbstate_t>, public generic_codecvt_base
{
public:
typedef CharType uchar;
generic_codecvt(size_t refs = 0) :
std::codecvt<CharType,char,std::mbstate_t>(refs)
{
}
CodecvtImpl const &implementation() const
{
return *static_cast<CodecvtImpl const *>(this);
}
protected:
virtual std::codecvt_base::result do_unshift(std::mbstate_t &s,char *from,char * /*to*/,char *&next) const
{
boost::uint16_t &state = *reinterpret_cast<boost::uint16_t *>(&s);
#ifdef DEBUG_CODECVT
std::cout << "Entering unshift " << std::hex << state << std::dec << std::endl;
#endif
if(state != 0)
return std::codecvt_base::error;
next=from;
return std::codecvt_base::ok;
}
virtual int do_encoding() const throw()
{
return 0;
}
virtual int do_max_length() const throw()
{
return implementation().max_encoding_length();
}
virtual bool do_always_noconv() const throw()
{
return false;
}
virtual int
do_length( std::mbstate_t
#ifdef BOOST_LOCALE_DO_LENGTH_MBSTATE_CONST
const
#endif
&std_state,
char const *from,
char const *from_end,
size_t max) const
{
#ifndef BOOST_LOCALE_DO_LENGTH_MBSTATE_CONST
char const *save_from = from;
boost::uint16_t &state = *reinterpret_cast<boost::uint16_t *>(&std_state);
#else
size_t save_max = max;
boost::uint16_t state = *reinterpret_cast<boost::uint16_t const *>(&std_state);
#endif
typedef typename CodecvtImpl::state_type state_type;
state_type cvt_state = implementation().initial_state(generic_codecvt_base::to_unicode_state);
while(max > 0 && from < from_end){
char const *prev_from = from;
boost::uint32_t ch=implementation().to_unicode(cvt_state,from,from_end);
if(ch==boost::locale::utf::incomplete || ch==boost::locale::utf::illegal) {
from = prev_from;
break;
}
max --;
if(ch > 0xFFFF) {
if(state == 0) {
from = prev_from;
state = 1;
}
else {
state = 0;
}
}
}
#ifndef BOOST_LOCALE_DO_LENGTH_MBSTATE_CONST
return from - save_from;
#else
return save_max - max;
#endif
}
virtual std::codecvt_base::result
do_in( std::mbstate_t &std_state,
char const *from,
char const *from_end,
char const *&from_next,
uchar *to,
uchar *to_end,
uchar *&to_next) const
{
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 observerd
// and first pair is written, but no input consumed
boost::uint16_t &state = *reinterpret_cast<boost::uint16_t *>(&std_state);
typedef typename CodecvtImpl::state_type state_type;
state_type cvt_state = implementation().initial_state(generic_codecvt_base::to_unicode_state);
while(to < to_end && from < from_end)
{
#ifdef DEBUG_CODECVT
std::cout << "Entering IN--------------" << std::endl;
std::cout << "State " << std::hex << state <<std::endl;
std::cout << "Left in " << std::dec << from_end - from << " out " << to_end -to << std::endl;
#endif
char const *from_saved = from;
uint32_t ch=implementation().to_unicode(cvt_state,from,from_end);
if(ch==boost::locale::utf::illegal) {
from = from_saved;
r=std::codecvt_base::error;
break;
}
if(ch==boost::locale::utf::incomplete) {
from = from_saved;
r=std::codecvt_base::partial;
break;
}
// Normal codepoints go direcly to stream
if(ch <= 0xFFFF) {
*to++=ch;
}
else {
// for other codepoints we do following
//
// 1. We can't consume our input as we may find ourselfs
// 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;
boost::uint16_t vh = ch >> 10;
boost::uint16_t vl = ch & 0x3FF;
boost::uint16_t w1 = vh + 0xD800;
boost::uint16_t w2 = vl + 0xDC00;
if(state == 0) {
from = from_saved;
*to++ = w1;
state = 1;
}
else {
*to++ = 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;
#ifdef DEBUG_CODECVT
std::cout << "Returning ";
switch(r) {
case std::codecvt_base::ok:
std::cout << "ok" << std::endl;
break;
case std::codecvt_base::partial:
std::cout << "partial" << std::endl;
break;
case std::codecvt_base::error:
std::cout << "error" << std::endl;
break;
default:
std::cout << "other" << std::endl;
break;
}
std::cout << "State " << std::hex << state <<std::endl;
std::cout << "Left in " << std::dec << from_end - from << " out " << to_end -to << std::endl;
#endif
return r;
}
virtual std::codecvt_base::result
do_out( std::mbstate_t &std_state,
uchar const *from,
uchar const *from_end,
uchar const *&from_next,
char *to,
char *to_end,
char *&to_next) const
{
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 observerd surrogate pair
//
// State: state!=0 - a first surrogate pair was observerd (state = first pair),
// we expect the second one to come and then zero the state
///
boost::uint16_t &state = *reinterpret_cast<boost::uint16_t *>(&std_state);
typedef typename CodecvtImpl::state_type state_type;
state_type cvt_state = implementation().initial_state(generic_codecvt_base::from_unicode_state);
while(to < to_end && from < from_end)
{
#ifdef DEBUG_CODECVT
std::cout << "Entering OUT --------------" << std::endl;
std::cout << "State " << std::hex << state <<std::endl;
std::cout << "Left in " << std::dec << from_end - from << " out " << to_end -to << std::endl;
#endif
boost::uint32_t ch=0;
if(state != 0) {
// if the state idecates that 1st surrogate pair was written
// we should make sure that the second one that comes is actually
// second surrogate
boost::uint16_t w1 = state;
boost::uint16_t w2 = *from;
// we don't forward from as writing may fail to incomplete or
// partial conversion
if(0xDC00 <= w2 && w2<=0xDFFF) {
boost::uint16_t vh = w1 - 0xD800;
boost::uint16_t vl = w2 - 0xDC00;
ch=((uint32_t(vh) << 10) | vl) + 0x10000;
}
else {
// Invalid surrogate
r=std::codecvt_base::error;
break;
}
}
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 = 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
r=std::codecvt_base::error;
break;
}
}
if(!boost::locale::utf::is_valid_codepoint(ch)) {
r=std::codecvt_base::error;
break;
}
boost::uint32_t len = implementation().from_unicode(cvt_state,ch,to,to_end);
if(len == boost::locale::utf::incomplete) {
r=std::codecvt_base::partial;
break;
}
else if(len == boost::locale::utf::illegal) {
r=std::codecvt_base::error;
break;
}
else
to+= len;
state = 0;
from++;
}
from_next=from;
to_next=to;
if(r==std::codecvt_base::ok && from!=from_end)
r = std::codecvt_base::partial;
#ifdef DEBUG_CODECVT
std::cout << "Returning ";
switch(r) {
case std::codecvt_base::ok:
std::cout << "ok" << std::endl;
break;
case std::codecvt_base::partial:
std::cout << "partial" << std::endl;
break;
case std::codecvt_base::error:
std::cout << "error" << std::endl;
break;
default:
std::cout << "other" << std::endl;
break;
}
std::cout << "State " << std::hex << state <<std::endl;
std::cout << "Left in " << std::dec << from_end - from << " out " << to_end -to << std::endl;
#endif
return r;
}
};
///
/// \brief UTF-32 to/from UTF-8 codecvt facet to use with char32_t or wchar_t on POSIX platforms
///
/// Its member functions implement standard virtual functions of basic codecvt.
/// mbstate_t is not used for UTF-32 handling due to fixed length encoding
///
template<typename CharType,typename CodecvtImpl>
class generic_codecvt<CharType,CodecvtImpl,4> : public std::codecvt<CharType,char,std::mbstate_t>, public generic_codecvt_base
{
public:
typedef CharType uchar;
generic_codecvt(size_t refs = 0) :
std::codecvt<CharType,char,std::mbstate_t>(refs)
{
}
CodecvtImpl const &implementation() const
{
return *static_cast<CodecvtImpl const *>(this);
}
protected:
virtual std::codecvt_base::result do_unshift(std::mbstate_t &/*s*/,char *from,char * /*to*/,char *&next) const
{
next=from;
return std::codecvt_base::ok;
}
virtual int do_encoding() const throw()
{
return 0;
}
virtual int do_max_length() const throw()
{
return implementation().max_encoding_length();
}
virtual bool do_always_noconv() const throw()
{
return false;
}
virtual int
do_length( std::mbstate_t
#ifdef BOOST_LOCALE_DO_LENGTH_MBSTATE_CONST
const
#endif
&/*state*/,
char const *from,
char const *from_end,
size_t max) const
{
#ifndef BOOST_LOCALE_DO_LENGTH_MBSTATE_CONST
char const *start_from = from;
#else
size_t save_max = max;
#endif
typedef typename CodecvtImpl::state_type state_type;
state_type cvt_state = implementation().initial_state(generic_codecvt_base::to_unicode_state);
while(max > 0 && from < from_end){
char const *save_from = from;
boost::uint32_t ch=implementation().to_unicode(cvt_state,from,from_end);
if(ch==boost::locale::utf::incomplete || ch==boost::locale::utf::illegal) {
from = save_from;
break;
}
max--;
}
#ifndef BOOST_LOCALE_DO_LENGTH_MBSTATE_CONST
return from - start_from;
#else
return save_max - max;
#endif
}
virtual std::codecvt_base::result
do_in( std::mbstate_t &/*state*/,
char const *from,
char const *from_end,
char const *&from_next,
uchar *to,
uchar *to_end,
uchar *&to_next) const
{
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 observerd
// and first pair is written, but no input consumed
typedef typename CodecvtImpl::state_type state_type;
state_type cvt_state = implementation().initial_state(generic_codecvt_base::to_unicode_state);
while(to < to_end && from < from_end)
{
#ifdef DEBUG_CODECVT
std::cout << "Entering IN--------------" << std::endl;
std::cout << "State " << std::hex << state <<std::endl;
std::cout << "Left in " << std::dec << from_end - from << " out " << to_end -to << std::endl;
#endif
char const *from_saved = from;
uint32_t ch=implementation().to_unicode(cvt_state,from,from_end);
if(ch==boost::locale::utf::illegal) {
r=std::codecvt_base::error;
from = from_saved;
break;
}
if(ch==boost::locale::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;
#ifdef DEBUG_CODECVT
std::cout << "Returning ";
switch(r) {
case std::codecvt_base::ok:
std::cout << "ok" << std::endl;
break;
case std::codecvt_base::partial:
std::cout << "partial" << std::endl;
break;
case std::codecvt_base::error:
std::cout << "error" << std::endl;
break;
default:
std::cout << "other" << std::endl;
break;
}
std::cout << "State " << std::hex << state <<std::endl;
std::cout << "Left in " << std::dec << from_end - from << " out " << to_end -to << std::endl;
#endif
return r;
}
virtual std::codecvt_base::result
do_out( std::mbstate_t &/*std_state*/,
uchar const *from,
uchar const *from_end,
uchar const *&from_next,
char *to,
char *to_end,
char *&to_next) const
{
std::codecvt_base::result r=std::codecvt_base::ok;
typedef typename CodecvtImpl::state_type state_type;
state_type cvt_state = implementation().initial_state(generic_codecvt_base::from_unicode_state);
while(to < to_end && from < from_end)
{
#ifdef DEBUG_CODECVT
std::cout << "Entering OUT --------------" << std::endl;
std::cout << "State " << std::hex << state <<std::endl;
std::cout << "Left in " << std::dec << from_end - from << " out " << to_end -to << std::endl;
#endif
boost::uint32_t ch=0;
ch = *from;
if(!boost::locale::utf::is_valid_codepoint(ch)) {
r=std::codecvt_base::error;
break;
}
boost::uint32_t len = implementation().from_unicode(cvt_state,ch,to,to_end);
if(len == boost::locale::utf::incomplete) {
r=std::codecvt_base::partial;
break;
}
else if(len == boost::locale::utf::illegal) {
r=std::codecvt_base::error;
break;
}
to+=len;
from++;
}
from_next=from;
to_next=to;
if(r==std::codecvt_base::ok && from!=from_end)
r = std::codecvt_base::partial;
#ifdef DEBUG_CODECVT
std::cout << "Returning ";
switch(r) {
case std::codecvt_base::ok:
std::cout << "ok" << std::endl;
break;
case std::codecvt_base::partial:
std::cout << "partial" << std::endl;
break;
case std::codecvt_base::error:
std::cout << "error" << std::endl;
break;
default:
std::cout << "other" << std::endl;
break;
}
std::cout << "State " << std::hex << state <<std::endl;
std::cout << "Left in " << std::dec << from_end - from << " out " << to_end -to << std::endl;
#endif
return r;
}
};
template<typename CharType,typename CodecvtImpl>
class generic_codecvt<CharType,CodecvtImpl,1> : public std::codecvt<CharType,char,std::mbstate_t>, public generic_codecvt_base
{
public:
typedef CharType uchar;
CodecvtImpl const &implementation() const
{
return *static_cast<CodecvtImpl const *>(this);
}
generic_codecvt(size_t refs = 0) : std::codecvt<char,char,std::mbstate_t>(refs)
{
}
};
} // locale
} // namespace boost
#endif
///
// vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4