/*

 *

 * Copyright (c) 1998-2002

 * John Maddock

 *

 * Use, modification and distribution are 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)

 *

 */

 /*

  *   LOCATION:    see http://www.boost.org for most recent version.

  *   FILE:        primary_transform.hpp

  *   VERSION:     see <boost/version.hpp>

  *   DESCRIPTION: Heuristically determines the sort string format in use

  *                by the current locale.

  */

#ifndef BOOST_REGEX_PRIMARY_TRANSFORM

#define BOOST_REGEX_PRIMARY_TRANSFORM

#ifdef BOOST_MSVC

#pragma warning(push)

#pragma warning(disable: 4103)

#endif

#ifdef BOOST_HAS_ABI_HEADERS

#  include BOOST_ABI_PREFIX

#endif

#ifdef BOOST_MSVC

#pragma warning(pop)

#endif

namespace boost{

   namespace re_detail{

enum{

   sort_C,

   sort_fixed,

   sort_delim,

   sort_unknown

};

template <class S, class charT>

unsigned count_chars(const S& s, charT c)

{

   //

   // Count how many occurances of character c occur

   // in string s: if c is a delimeter between collation

   // fields, then this should be the same value for all

   // sort keys:

   //

   unsigned int count = 0;

   for(unsigned pos = 0; pos < s.size(); ++pos)

   {

      if(s[pos] == c) ++count;

   }

   return count;

}

template <class traits, class charT>

unsigned find_sort_syntax(const traits* pt, charT* delim)

{

   //

   // compare 'a' with 'A' to see how similar they are,

   // should really use a-accute but we can't portably do that,

   //

   typedef typename traits::string_type string_type;

   typedef typename traits::char_type char_type;

   // Suppress incorrect warning for MSVC

   (void)pt;

   char_type a[2] = {'a', '\0', };

   string_type sa(pt->transform(a, a+1));

   if(sa == a)

   {

      *delim = 0;

      return sort_C;

   }

   char_type A[2] = { 'A', '\0', };

   string_type sA(pt->transform(A, A+1));

   char_type c[2] = { ';', '\0', };

   string_type sc(pt->transform(c, c+1));

   int pos = 0;

   while((pos <= static_cast<int>(sa.size())) && (pos <= static_cast<int>(sA.size())) && (sa[pos] == sA[pos])) ++pos;

   --pos;

   if(pos < 0)

   {

      *delim = 0;

      return sort_unknown;

   }

   //

   // at this point sa[pos] is either the end of a fixed width field

   // or the character that acts as a delimiter:

   //

   charT maybe_delim = sa[pos];

   if((pos != 0) && (count_chars(sa, maybe_delim) == count_chars(sA, maybe_delim)) && (count_chars(sa, maybe_delim) == count_chars(sc, maybe_delim)))

   {

      *delim = maybe_delim;

      return sort_delim;

   }

   //

   // OK doen't look like a delimiter, try for fixed width field:

   //

   if((sa.size() == sA.size()) && (sa.size() == sc.size()))

   {

      // note assumes that the fixed width field is less than

      // (numeric_limits<charT>::max)(), should be true for all types

      // I can't imagine 127 character fields...

      *delim = static_cast<charT>(++pos);

      return sort_fixed;

   }

   //

   // don't know what it is:

   //

   *delim = 0;

   return sort_unknown;

}

   } // namespace re_detail

} // namespace boost

#ifdef BOOST_MSVC

#pragma warning(push)

#pragma warning(disable: 4103)

#endif

#ifdef BOOST_HAS_ABI_HEADERS

#  include BOOST_ABI_SUFFIX

#endif

#ifdef BOOST_MSVC

#pragma warning(pop)

#endif

#endif