147 lines
3.2 KiB
C++
147 lines
3.2 KiB
C++
/*
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*
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* Copyright (c) 1998-2002
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* John Maddock
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*
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* Use, modification and distribution are subject to the
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* Boost Software License, Version 1.0. (See accompanying file
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* LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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*
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*/
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/*
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* LOCATION: see http://www.boost.org for most recent version.
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* FILE: primary_transform.hpp
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* VERSION: see <boost/version.hpp>
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* DESCRIPTION: Heuristically determines the sort string format in use
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* by the current locale.
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*/
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#ifndef BOOST_REGEX_PRIMARY_TRANSFORM
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#define BOOST_REGEX_PRIMARY_TRANSFORM
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#ifdef BOOST_MSVC
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#pragma warning(push)
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#pragma warning(disable: 4103)
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#endif
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#ifdef BOOST_HAS_ABI_HEADERS
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# include BOOST_ABI_PREFIX
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#endif
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#ifdef BOOST_MSVC
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#pragma warning(pop)
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#endif
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namespace boost{
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namespace re_detail{
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enum{
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sort_C,
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sort_fixed,
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sort_delim,
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sort_unknown
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};
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template <class S, class charT>
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unsigned count_chars(const S& s, charT c)
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{
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//
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// Count how many occurances of character c occur
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// in string s: if c is a delimeter between collation
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// fields, then this should be the same value for all
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// sort keys:
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//
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unsigned int count = 0;
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for(unsigned pos = 0; pos < s.size(); ++pos)
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{
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if(s[pos] == c) ++count;
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}
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return count;
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}
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template <class traits, class charT>
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unsigned find_sort_syntax(const traits* pt, charT* delim)
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{
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//
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// compare 'a' with 'A' to see how similar they are,
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// should really use a-accute but we can't portably do that,
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//
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typedef typename traits::string_type string_type;
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typedef typename traits::char_type char_type;
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// Suppress incorrect warning for MSVC
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(void)pt;
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char_type a[2] = {'a', '\0', };
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string_type sa(pt->transform(a, a+1));
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if(sa == a)
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{
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*delim = 0;
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return sort_C;
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}
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char_type A[2] = { 'A', '\0', };
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string_type sA(pt->transform(A, A+1));
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char_type c[2] = { ';', '\0', };
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string_type sc(pt->transform(c, c+1));
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int pos = 0;
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while((pos <= static_cast<int>(sa.size())) && (pos <= static_cast<int>(sA.size())) && (sa[pos] == sA[pos])) ++pos;
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--pos;
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if(pos < 0)
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{
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*delim = 0;
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return sort_unknown;
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}
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//
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// at this point sa[pos] is either the end of a fixed width field
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// or the character that acts as a delimiter:
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//
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charT maybe_delim = sa[pos];
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if((pos != 0) && (count_chars(sa, maybe_delim) == count_chars(sA, maybe_delim)) && (count_chars(sa, maybe_delim) == count_chars(sc, maybe_delim)))
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{
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*delim = maybe_delim;
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return sort_delim;
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}
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//
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// OK doen't look like a delimiter, try for fixed width field:
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//
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if((sa.size() == sA.size()) && (sa.size() == sc.size()))
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{
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// note assumes that the fixed width field is less than
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// (numeric_limits<charT>::max)(), should be true for all types
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// I can't imagine 127 character fields...
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*delim = static_cast<charT>(++pos);
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return sort_fixed;
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}
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//
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// don't know what it is:
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//
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*delim = 0;
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return sort_unknown;
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}
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} // namespace re_detail
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} // namespace boost
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#ifdef BOOST_MSVC
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#pragma warning(push)
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#pragma warning(disable: 4103)
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#endif
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#ifdef BOOST_HAS_ABI_HEADERS
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# include BOOST_ABI_SUFFIX
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#endif
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#ifdef BOOST_MSVC
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#pragma warning(pop)
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#endif
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#endif
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