mirror of
https://github.com/yuzu-emu/ext-boost.git
synced 2024-12-23 04:55:27 +00:00
285 lines
9.2 KiB
C++
285 lines
9.2 KiB
C++
/////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
|
|
// utf8_codecvt_facet.ipp
|
|
|
|
// Copyright (c) 2001 Ronald Garcia, Indiana University (garcia@osl.iu.edu)
|
|
// Andrew Lumsdaine, Indiana University (lums@osl.iu.edu).
|
|
// Use, modification and distribution is subject to 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)
|
|
|
|
// Please see the comments in <boost/detail/utf8_codecvt_facet.hpp> to
|
|
// learn how this file should be used.
|
|
|
|
#include <boost/detail/utf8_codecvt_facet.hpp>
|
|
|
|
#include <cstdlib> // for multi-byte converson routines
|
|
#include <cassert>
|
|
|
|
#include <boost/limits.hpp>
|
|
#include <boost/config.hpp>
|
|
|
|
// If we don't have wstring, then Unicode support
|
|
// is not available anyway, so we don't need to even
|
|
// compiler this file. This also fixes the problem
|
|
// with mingw, which can compile this file, but will
|
|
// generate link error when building DLL.
|
|
#ifndef BOOST_NO_STD_WSTRING
|
|
|
|
BOOST_UTF8_BEGIN_NAMESPACE
|
|
|
|
/////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
|
|
// implementation for wchar_t
|
|
|
|
// Translate incoming UTF-8 into UCS-4
|
|
std::codecvt_base::result utf8_codecvt_facet::do_in(
|
|
std::mbstate_t& /*state*/,
|
|
const char * from,
|
|
const char * from_end,
|
|
const char * & from_next,
|
|
wchar_t * to,
|
|
wchar_t * to_end,
|
|
wchar_t * & to_next
|
|
) const {
|
|
// Basic algorithm: The first octet determines how many
|
|
// octets total make up the UCS-4 character. The remaining
|
|
// "continuing octets" all begin with "10". To convert, subtract
|
|
// the amount that specifies the number of octets from the first
|
|
// octet. Subtract 0x80 (1000 0000) from each continuing octet,
|
|
// then mash the whole lot together. Note that each continuing
|
|
// octet only uses 6 bits as unique values, so only shift by
|
|
// multiples of 6 to combine.
|
|
while (from != from_end && to != to_end) {
|
|
|
|
// Error checking on the first octet
|
|
if (invalid_leading_octet(*from)){
|
|
from_next = from;
|
|
to_next = to;
|
|
return std::codecvt_base::error;
|
|
}
|
|
|
|
// The first octet is adjusted by a value dependent upon
|
|
// the number of "continuing octets" encoding the character
|
|
const int cont_octet_count = get_cont_octet_count(*from);
|
|
const wchar_t octet1_modifier_table[] = {
|
|
0x00, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc
|
|
};
|
|
|
|
// The unsigned char conversion is necessary in case char is
|
|
// signed (I learned this the hard way)
|
|
wchar_t ucs_result =
|
|
(unsigned char)(*from++) - octet1_modifier_table[cont_octet_count];
|
|
|
|
// Invariants :
|
|
// 1) At the start of the loop, 'i' continuing characters have been
|
|
// processed
|
|
// 2) *from points to the next continuing character to be processed.
|
|
int i = 0;
|
|
while(i != cont_octet_count && from != from_end) {
|
|
|
|
// Error checking on continuing characters
|
|
if (invalid_continuing_octet(*from)) {
|
|
from_next = from;
|
|
to_next = to;
|
|
return std::codecvt_base::error;
|
|
}
|
|
|
|
ucs_result *= (1 << 6);
|
|
|
|
// each continuing character has an extra (10xxxxxx)b attached to
|
|
// it that must be removed.
|
|
ucs_result += (unsigned char)(*from++) - 0x80;
|
|
++i;
|
|
}
|
|
|
|
// If the buffer ends with an incomplete unicode character...
|
|
if (from == from_end && i != cont_octet_count) {
|
|
// rewind "from" to before the current character translation
|
|
from_next = from - (i+1);
|
|
to_next = to;
|
|
return std::codecvt_base::partial;
|
|
}
|
|
*to++ = ucs_result;
|
|
}
|
|
from_next = from;
|
|
to_next = to;
|
|
|
|
// Were we done converting or did we run out of destination space?
|
|
if(from == from_end) return std::codecvt_base::ok;
|
|
else return std::codecvt_base::partial;
|
|
}
|
|
|
|
std::codecvt_base::result utf8_codecvt_facet::do_out(
|
|
std::mbstate_t& /*state*/,
|
|
const wchar_t * from,
|
|
const wchar_t * from_end,
|
|
const wchar_t * & from_next,
|
|
char * to,
|
|
char * to_end,
|
|
char * & to_next
|
|
) const
|
|
{
|
|
// RG - consider merging this table with the other one
|
|
const wchar_t octet1_modifier_table[] = {
|
|
0x00, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc
|
|
};
|
|
|
|
wchar_t max_wchar = (std::numeric_limits<wchar_t>::max)();
|
|
while (from != from_end && to != to_end) {
|
|
|
|
// Check for invalid UCS-4 character
|
|
if (*from > max_wchar) {
|
|
from_next = from;
|
|
to_next = to;
|
|
return std::codecvt_base::error;
|
|
}
|
|
|
|
int cont_octet_count = get_cont_octet_out_count(*from);
|
|
|
|
// RG - comment this formula better
|
|
int shift_exponent = (cont_octet_count) * 6;
|
|
|
|
// Process the first character
|
|
*to++ = static_cast<char>(octet1_modifier_table[cont_octet_count] +
|
|
(unsigned char)(*from / (1 << shift_exponent)));
|
|
|
|
// Process the continuation characters
|
|
// Invariants: At the start of the loop:
|
|
// 1) 'i' continuing octets have been generated
|
|
// 2) '*to' points to the next location to place an octet
|
|
// 3) shift_exponent is 6 more than needed for the next octet
|
|
int i = 0;
|
|
while (i != cont_octet_count && to != to_end) {
|
|
shift_exponent -= 6;
|
|
*to++ = static_cast<char>(0x80 + ((*from / (1 << shift_exponent)) % (1 << 6)));
|
|
++i;
|
|
}
|
|
// If we filled up the out buffer before encoding the character
|
|
if(to == to_end && i != cont_octet_count) {
|
|
from_next = from;
|
|
to_next = to - (i+1);
|
|
return std::codecvt_base::partial;
|
|
}
|
|
++from;
|
|
}
|
|
from_next = from;
|
|
to_next = to;
|
|
// Were we done or did we run out of destination space
|
|
if(from == from_end) return std::codecvt_base::ok;
|
|
else return std::codecvt_base::partial;
|
|
}
|
|
|
|
// How many char objects can I process to get <= max_limit
|
|
// wchar_t objects?
|
|
int utf8_codecvt_facet::do_length(
|
|
const std::mbstate_t &,
|
|
const char * from,
|
|
const char * from_end,
|
|
std::size_t max_limit
|
|
) const
|
|
#if BOOST_WORKAROUND(__IBMCPP__, BOOST_TESTED_AT(600))
|
|
throw()
|
|
#endif
|
|
{
|
|
// RG - this code is confusing! I need a better way to express it.
|
|
// and test cases.
|
|
|
|
// Invariants:
|
|
// 1) last_octet_count has the size of the last measured character
|
|
// 2) char_count holds the number of characters shown to fit
|
|
// within the bounds so far (no greater than max_limit)
|
|
// 3) from_next points to the octet 'last_octet_count' before the
|
|
// last measured character.
|
|
int last_octet_count=0;
|
|
std::size_t char_count = 0;
|
|
const char* from_next = from;
|
|
// Use "<" because the buffer may represent incomplete characters
|
|
while (from_next+last_octet_count <= from_end && char_count <= max_limit) {
|
|
from_next += last_octet_count;
|
|
last_octet_count = (get_octet_count(*from_next));
|
|
++char_count;
|
|
}
|
|
return static_cast<int>(from_next-from_end);
|
|
}
|
|
|
|
unsigned int utf8_codecvt_facet::get_octet_count(
|
|
unsigned char lead_octet
|
|
){
|
|
// if the 0-bit (MSB) is 0, then 1 character
|
|
if (lead_octet <= 0x7f) return 1;
|
|
|
|
// Otherwise the count number of consecutive 1 bits starting at MSB
|
|
// assert(0xc0 <= lead_octet && lead_octet <= 0xfd);
|
|
|
|
if (0xc0 <= lead_octet && lead_octet <= 0xdf) return 2;
|
|
else if (0xe0 <= lead_octet && lead_octet <= 0xef) return 3;
|
|
else if (0xf0 <= lead_octet && lead_octet <= 0xf7) return 4;
|
|
else if (0xf8 <= lead_octet && lead_octet <= 0xfb) return 5;
|
|
else return 6;
|
|
}
|
|
BOOST_UTF8_END_NAMESPACE
|
|
|
|
namespace {
|
|
template<std::size_t s>
|
|
int get_cont_octet_out_count_impl(wchar_t word){
|
|
if (word < 0x80) {
|
|
return 0;
|
|
}
|
|
if (word < 0x800) {
|
|
return 1;
|
|
}
|
|
return 2;
|
|
}
|
|
|
|
template<>
|
|
int get_cont_octet_out_count_impl<4>(wchar_t word){
|
|
if (word < 0x80) {
|
|
return 0;
|
|
}
|
|
if (word < 0x800) {
|
|
return 1;
|
|
}
|
|
|
|
// Note that the following code will generate warnings on some platforms
|
|
// where wchar_t is defined as UCS2. The warnings are superfluous as the
|
|
// specialization is never instantitiated with such compilers, but this
|
|
// can cause problems if warnings are being treated as errors, so we guard
|
|
// against that. Including <boost/detail/utf8_codecvt_facet.hpp> as we do
|
|
// should be enough to get WCHAR_MAX defined.
|
|
#if !defined(WCHAR_MAX)
|
|
# error WCHAR_MAX not defined!
|
|
#endif
|
|
// cope with VC++ 7.1 or earlier having invalid WCHAR_MAX
|
|
#if defined(_MSC_VER) && _MSC_VER <= 1310 // 7.1 or earlier
|
|
return 2;
|
|
#elif WCHAR_MAX > 0x10000
|
|
|
|
if (word < 0x10000) {
|
|
return 2;
|
|
}
|
|
if (word < 0x200000) {
|
|
return 3;
|
|
}
|
|
if (word < 0x4000000) {
|
|
return 4;
|
|
}
|
|
return 5;
|
|
|
|
#else
|
|
return 2;
|
|
#endif
|
|
}
|
|
|
|
} // namespace anonymous
|
|
|
|
BOOST_UTF8_BEGIN_NAMESPACE
|
|
// How many "continuing octets" will be needed for this word
|
|
// == total octets - 1.
|
|
int utf8_codecvt_facet::get_cont_octet_out_count(
|
|
wchar_t word
|
|
) const {
|
|
return get_cont_octet_out_count_impl<sizeof(wchar_t)>(word);
|
|
}
|
|
BOOST_UTF8_END_NAMESPACE
|
|
|
|
#endif
|