| /* |
| * stringtok.h -- 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... |
| */ |
| namespace { |
| inline bool |
| isws (char c, char const * const wstr) |
| { |
| return (strchr(wstr,c) != NULL); |
| } |
| } |
| |
| |
| /***************************************************************** |
| * 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, string const &s, char const * const ws = " \t\n") |
| { |
| const string::size_type S = s.size(); |
| string::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 |
| string::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; |
| } |
| } |
| |
| |