split.h

Go to the documentation of this file.

#ifndef cetlib_split_h
#define cetlib_split_h

// ======================================================================
//
// split: Obtain substrings at a string's specified boundaries.
//
// Examples of splitting with ':' as the separator:
//    input     result
//     ""       [ ]                # Different behavior than split_by_regex.h
//     "a"      ["a"]
//     "a:"     ["a"]
//     ":boo"   ["boo"]            # Different behavior than split_by_regex.h
//     "a:b"    ["a","b"]
//     "a::b"   ["a","b"] // N.B.! # Different behavior than split_by_regex.h
//
// ======================================================================

#include <algorithm>
#include <functional>
#include <string>

namespace cet {
  template <class OutIter>
  void split(std::string const& s, char c, OutIter dest);

  template <class Pred, class OutIter>
  void split_if(std::string const& s, Pred is_sep, OutIter dest);
}

// ======================================================================

template <class OutIter>
void
cet::split(std::string const& s, char c, OutIter dest)
{
  split_if(s, [c](char x) { return x == c; }, dest);
}

// ======================================================================

template <class Pred, class OutIter>
void
cet::split_if(std::string const& s, Pred is_sep, OutIter dest)
{
  auto const e = s.cend();
  auto const is_not_sep = [is_sep](auto const c) { return !is_sep(c); };
  auto const new_boi = [is_not_sep, &e](auto const si) {
    return std::find_if(si, e, is_not_sep);
  };
  // invariant:  we've found all items in [b..boi)
  // e is an arbitrary value to use as the initializer
  for (typename std::remove_const<decltype(e)>::type boi = new_boi(s.cbegin()),
                                                     eoi = e;
       boi != e;
       boi = new_boi(eoi)) // advance to next non-separator
  {
    // find end of current item:
    eoi = std::find_if(boi, e, is_sep);

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

} // split_if<>()

// ======================================================================

#endif /* cetlib_split_h */

// Local variables:
// mode:c++
// End: