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'thread_rewrite'.

[SVN r30953]
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nobody
2005-09-13 14:20:32 +00:00
parent 33ff8d33be
commit 2be78fa25d
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utf8_codecvt_facet.cpp
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@ -1,269 +0,0 @@
/////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
// utf8_codecvt_facet.cpp
// Copyright <20> 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++ = 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++ = 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(
BOOST_CODECVT_DO_LENGTH_CONST std::mbstate_t &,
const char * from,
const char * from_end,
std::size_t max_limit
#if BOOST_WORKAROUND(__IBMCPP__, BOOST_TESTED_AT(600))
) const throw()
#else
) const
#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 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;
}
// note the following code will generate on some platforms where
// wchar_t is defined as UCS2. The warnings are superfluous as
// the specialization is never instantitiated with such compilers.
template<>
int get_cont_octet_out_count_impl<4>(wchar_t word){
if (word < 0x80) {
return 0;
}
if (word < 0x800) {
return 1;
}
if (word < 0x10000) {
return 2;
}
if (word < 0x200000) {
return 3;
}
if (word < 0x4000000) {
return 4;
}
return 5;
}
} // 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