src/string_base.h

   1 /* $Id$ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   6  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   7  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   8  */
   9
  10 #ifndef STRING_BASE_H
  11 #define STRING_BASE_H
  12
  13 #include "string_type.h"
  14
  15 /** Class for iterating over different kind of parts of a string. */
  16 class StringIterator {
  17 public:
  18         /** Type of the iterator. */
  19         enum IterType {
  20                 ITER_CHARACTER, ///< Iterate over characters (or more exactly grapheme clusters).
  21                 ITER_WORD,      ///< Iterate over words.
  22         };
  23
  24         /** Sentinel to indicate end-of-iteration. */
  25         static const size_t END = SIZE_MAX;
  26
  27         /**
  28          * Create a new iterator instance.
  29          * @return New iterator instance.
  30          */
  31         static StringIterator *Create();
  32
  33         virtual ~StringIterator() {}
  34
  35         /**
  36          * Set a new iteration string. Must also be called if the string contents
  37          * changed. The cursor is reset to the start of the string.
  38          * @param s New string.
  39          */
  40         virtual void SetString(const char *s) = 0;
  41
  42         /**
  43          * Change the current string cursor.
  44          * @param p New cursor position.
  45          * @return Actual new cursor position at the next valid character boundary.
  46          * @pre p has to be inside the current string.
  47          */
  48         virtual size_t SetCurPosition(size_t pos) = 0;
  49
  50         /**
  51          * Advance the cursor by one iteration unit.
  52          * @return New cursor position (in bytes) or #END if the cursor is already at the end of the string.
  53          */
  54         virtual size_t Next(IterType what = ITER_CHARACTER) = 0;
  55
  56         /**
  57          * Move the cursor back by one iteration unit.
  58          * @return New cursor position (in bytes) or #END if the cursor is already at the start of the string.
  59          */
  60         virtual size_t Prev(IterType what = ITER_CHARACTER) = 0;
  61
  62 protected:
  63         StringIterator() {}
  64 };
  65
  66 #endif /* STRING_BASE_H */