view dw/findtext.cc @ 2030:382160be8c2f

cookies comments I was going to say something in the comments about simplicity and not implementing every little bit of the rfc when we don't know of cookies that make it necessary, but then I suppose that's all implied with dillo.
author corvid <corvid@lavabit.com>
date Tue, 17 May 2011 22:48:50 +0000
parents 74925c1746dd
children 420e8aa657ff
line wrap: on
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/*
 * Dillo Widget
 *
 * Copyright 2005-2007 Sebastian Geerken <sgeerken@dillo.org>
 *
 * This program 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; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */



#include "core.hh"
#include "../lout/msg.h"

namespace dw {
namespace core {

FindtextState::FindtextState ()
{
   key = NULL;
   nexttab = NULL;
   widget = NULL;
   iterator = NULL;
   hlIterator = NULL;
}

FindtextState::~FindtextState ()
{
   if (key)
      free(key);
   if (nexttab)
      delete[] nexttab;
   if (iterator)
      delete iterator;
   if (hlIterator)
      delete hlIterator;
}

void FindtextState::setWidget (Widget *widget)
{
   this->widget = widget;

   // A widget change will restart the search.
   if (key)
      free(key);
   key = NULL;
   if (nexttab)
      delete[] nexttab;
   nexttab = NULL;

   if (iterator)
      delete iterator;
   iterator = NULL;
   if (hlIterator)
      delete hlIterator;
   hlIterator = NULL;
}

FindtextState::Result FindtextState::search (const char *key, bool caseSens,
                                             bool backwards)
{
   if (!widget || *key == 0) // empty keys are not found
      return NOT_FOUND;

   bool wasHighlighted = unhighlight ();
   bool newKey;

   // If the key (or the widget) changes (including case sensitivity),
   // the search is started from the beginning.
   if (this->key == NULL || this->caseSens != caseSens ||
       strcmp (this->key, key) != 0) {
      newKey = true;
      if (this->key)
         free(this->key);
      this->key = strdup (key);
      this->caseSens = caseSens;

      if (nexttab)
         delete[] nexttab;
      nexttab = createNexttab (key, caseSens, backwards);

      if (iterator)
         delete iterator;
      iterator = new CharIterator (widget);

      if (backwards) {
         /* Go to end */
         while (iterator->next () ) ;
         iterator->prev (); //We don't want to be at CharIterator::END.
      } else {
         iterator->next ();
      }
   } else
      newKey = false;

   bool firstTrial = !wasHighlighted || newKey;

   if (search0 (backwards, firstTrial)) {
      // Highlighlighting is done with a clone.
      hlIterator = iterator->cloneCharIterator ();
      for (int i = 0; key[i]; i++)
         hlIterator->next ();
      CharIterator::highlight (iterator, hlIterator, HIGHLIGHT_FINDTEXT);
      CharIterator::scrollTo (iterator, hlIterator,
                              HPOS_INTO_VIEW, VPOS_CENTER);

      // The search will continue from the word after the found position.
      iterator->next ();
      return SUCCESS;
   } else {
      if (firstTrial) {
         return NOT_FOUND;
      } else {
         // Nothing found anymore, reset the state for the next trial.
         delete iterator;
         iterator = new CharIterator (widget);
         if (backwards) {
            /* Go to end */
            while (iterator->next ()) ;
            iterator->prev (); //We don't want to be at CharIterator::END.
         } else {
            iterator->next ();
         }
         // We expect a success.
         Result result2 = search (key, caseSens, backwards);
         assert (result2 == SUCCESS);
         return RESTART;
      }
   }
}

/**
 * \brief This method is called when the user closes the "find text" dialog.
 */
void FindtextState::resetSearch ()
{
   unhighlight ();

   if (key)
      free(key);
   key = NULL;
}

/*
 * Return a new string: with the reverse of the original.
 */
const char* FindtextState::rev(const char *str)
{
   if (!str)
      return NULL;

   int len = strlen(str);
   char *nstr = new char[len+1];
   for (int i = 0; i < len; ++i)
      nstr[i] = str[len-1 -i];
   nstr[len] = 0;

   return nstr;
}

int *FindtextState::createNexttab (const char *needle, bool caseSens,
                                   bool backwards)
{
   const char* key;

   key = (backwards) ? rev(needle) : needle;
   int i = 0;
   int j = -1;
   int l = strlen (key);
   int *nexttab = new int[l + 1]; // + 1 is necessary for l == 1 case
   nexttab[0] = -1;

   do {
      if (j == -1 || charsEqual (key[i], key[j], caseSens)) {
         i++;
         j++;
         nexttab[i] = j;
         //_MSG ("nexttab[%d] = %d\n", i, j);
      } else
         j = nexttab[j];
   } while (i < l - 1);

   if (backwards)
      delete [] key;

   return nexttab;
}

/**
 * \brief Unhighlight, and return whether a region was highlighted.
 */
bool FindtextState::unhighlight ()
{
   if (hlIterator) {
      CharIterator *start = hlIterator->cloneCharIterator ();
      for (int i = 0; key[i]; i++)
         start->prev ();

      CharIterator::unhighlight (start, hlIterator, HIGHLIGHT_FINDTEXT);
      delete start;
      delete hlIterator;
      hlIterator = NULL;

      return true;
   } else
      return false;
}

bool FindtextState::search0 (bool backwards,  bool firstTrial)
{
   if (iterator->getChar () == CharIterator::END)
      return false;

   bool ret = false;
   const char* searchKey = (backwards) ? rev(key) : key;
   int j = 0;
   bool nextit = true;
   int l = strlen (key);

   if (backwards && !firstTrial) {
      _MSG("Having to do.");
      /* Position correctly */
      /* In order to achieve good results (i.e: find a word that ends within
       * the previously searched word's limit) we have to position the
       * iterator in the semilast character of the previously searched word.
       *
       * Since we know that if a word was found before it was exactly the
       * same word as the one we are searching for now, we can apply the
       * following expression:
       *
       * Where l=length of the key and n=num of positions to move:
       *
       * n = l - 3
       *
       * If n is negative, we have to move backwards, but if it is
       * positive, we have to move forward. So, when l>=4, we start moving
       * the iterator forward. */

      if (l==1) {
         iterator->prev();
         iterator->prev();
      } else if (l==2) {
         iterator->prev();
      } else if (l>=4) {
         for (int i=0; i<l-3; i++) {
            iterator->next();
         }
      }

   } else if (backwards && l==1) {
      /* Particular case where we can't find the last character */
      iterator->next();
   }

   do {
      if (j == -1 || charsEqual (iterator->getChar(),searchKey[j],caseSens)) {
         j++;
         nextit = backwards ? iterator->prev () : iterator->next ();
      } else
         j = nexttab[j];
   } while (nextit && j < l);

   if (j >= l) {
      if (backwards) {
         //This is the location of the key
         iterator->next();
      } else {
         // Go back to where the key was found.
         for (int i = 0; i < l; i++)
            iterator->prev ();
      }
      ret = true;
   }

   if (backwards)
      delete [] searchKey;

   return ret;
}

} // namespace dw
} // namespace core