split.h

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#ifndef ParameterSet_split_h
#define ParameterSet_split_h

// ----------------------------------------------------------------------
// definition of split() and related templates
// ----------------------------------------------------------------------


// ----------------------------------------------------------------------
// prolog


// ----------------------------------------------------------------------
// prerequisite source files and headers

#include <string>


// ----------------------------------------------------------------------
// contents

namespace edm  {

  template< class FwdIter >
  FwdIter
    contextual_find(FwdIter b, FwdIter e
                   , char first, char sep, char last);

  template< class FwdIter >
  FwdIter
    contextual_find_not(FwdIter b, FwdIter e
                       , char first, char sep, char last);

  template< class OutIter >
  bool
    split(OutIter result
         , std::string const& string_to_split
         , char first, char sep, char last);

}  // namespace edm


// ----------------------------------------------------------------------
// contextual_find

template< class FwdIter >
FwdIter
  edm::contextual_find(FwdIter b, FwdIter e
                      , char first, char sep, char last)
{
  for(int  nested = 0;  b != e;  ++b)  {
    if(*b == first)
      ++nested;
    else if(*b == last)
      --nested;
    else if(*b == sep  &&  nested == 0)
      return b;
  }

  return e;

}  // contextual_find()


// ----------------------------------------------------------------------
// contextual_find_not

template< class FwdIter >
FwdIter
  edm::contextual_find_not(FwdIter b, FwdIter e
                          , char /* first */ , char sep, char /* last */)
{
  for(;  b != e;  ++b)  {
    if(*b != sep)
      return b;
  }

  return e;

}  // contextual_find_not()


// ----------------------------------------------------------------------
// split()

template< class OutIter >
bool
  edm::split(OutIter dest, std::string const& s
            , char first, char sep, char last)
{
  typedef  std::string::const_iterator  str_c_iter;
  str_c_iter  b = s.begin()
           ,  e = s.end();

  if(static_cast<unsigned int>(e - b) < 2u)  return false;

  if(*b == first)  ++b;
  else               return false;

  if(*--e != last)  return false;

  // invariant:  we've found all items in [b..boi)
  for(str_c_iter  //boi = std::find_if(b, e, is_not_a(sep))
                   boi = contextual_find_not(b, e, first, sep, last)
                ,  eoi
     ; boi != e
     //; boi = std::find_if(eoi, e, is_not_a(sep))
     ; boi = contextual_find_not(eoi, e, first, sep, last))
  {
    // find end of current item:
    //eoi = std::find_if(boi, e, is_a(sep));
    eoi = contextual_find(boi, e, first, sep, last);

    // copy the item formed from characters in [boi..eoi):
    *dest++ = std::string(boi, eoi);
  }  // for

  return true;
}  // split< >()


// ----------------------------------------------------------------------
// epilog

#endif