123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116 |
- // (C) Copyright Jeremy Siek 2004
- // Distributed under 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)
- #ifndef BOOST_STRINGTOK_HPP
- #define BOOST_STRINGTOK_HPP
- /*
- * stringtok.hpp -- Breaks a string into tokens. This is an example for lib3.
- *
- * Template function looks like this:
- *
- * template <typename Container>
- * void stringtok (Container &l,
- * string const &s,
- * char const * const ws = " \t\n");
- *
- * A nondestructive version of strtok() that handles its own memory and can
- * be broken up by any character(s). Does all the work at once rather than
- * in an invocation loop like strtok() requires.
- *
- * Container is any type that supports push_back(a_string), although using
- * list<string> and deque<string> are indicated due to their O(1) push_back.
- * (I prefer deque<> because op[]/at() is available as well.) The first
- * parameter references an existing Container.
- *
- * s is the string to be tokenized. From the parameter declaration, it can
- * be seen that s is not affected. Since references-to-const may refer to
- * temporaries, you could use stringtok(some_container, readline("")) when
- * using the GNU readline library.
- *
- * The final parameter is an array of characters that serve as whitespace.
- * Whitespace characters default to one or more of tab, space, and newline,
- * in any combination.
- *
- * 'l' need not be empty on entry. On return, 'l' will have the token
- * strings appended.
- *
- *
- * [Example:
- * list<string> ls;
- * stringtok (ls, " this \t is\t\n a test ");
- * for (list<string>::const_iterator i = ls.begin();
- * i != ls.end(); ++i)
- * {
- * cerr << ':' << (*i) << ":\n";
- * }
- *
- * would print
- * :this:
- * :is:
- * :a:
- * :test:
- * -end example]
- *
- * pedwards@jaj.com May 1999
- */
- #include <string>
- #include <cstring> // for strchr
- /*****************************************************************
- * This is the only part of the implementation that I don't like.
- * It can probably be improved upon by the reader...
- */
- inline bool
- isws (char c, char const * const wstr)
- {
- using namespace std;
- return (strchr(wstr,c) != NULL);
- }
- namespace boost {
- /*****************************************************************
- * Simplistic and quite Standard, but a bit slow. This should be
- * templatized on basic_string instead, or on a more generic StringT
- * that just happens to support ::size_type, .substr(), and so on.
- * I had hoped that "whitespace" would be a trait, but it isn't, so
- * the user must supply it. Enh, this lets them break up strings on
- * different things easier than traits would anyhow.
- */
- template <typename Container>
- void
- stringtok (Container &l, std::string const &s, char const * const ws = " \t\n")
- {
- typedef std::string::size_type size_type;
- const size_type S = s.size();
- size_type i = 0;
- while (i < S) {
- // eat leading whitespace
- while ((i < S) && (isws(s[i],ws))) ++i;
- if (i == S) return; // nothing left but WS
- // find end of word
- size_type j = i+1;
- while ((j < S) && (!isws(s[j],ws))) ++j;
- // add word
- l.push_back(s.substr(i,j-i));
- // set up for next loop
- i = j+1;
- }
- }
- } // namespace boost
- #endif // BOOST_STRINGTOK_HPP
|