intl/lwbrk/src/nsPangoBreaker.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
   7  * the License. You may obtain a copy of the License at
   8  * http://www.mozilla.org/MPL/
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  10  * Software distributed under the License is distributed on an "AS IS" basis,
  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12  * for the specific language governing rights and limitations under the
  13  * License.
  14  *
  15  * The Original Code is mozilla.org code.
  16  *
  17  * The Initial Developer of the Original Code is
  18  * Theppitak Karoonboonyanan <thep@linux.thai.net>.
  19  * Portions created by the Initial Developer are Copyright (C) 2007
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  * - Theppitak Karoonboonyanan <thep@linux.thai.net>
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either of the GNU General Public License Version 2 or later (the "GPL"),
  27  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  28  * in which case the provisions of the GPL or the LGPL are applicable instead
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  36  *
  37  * ***** END LICENSE BLOCK ***** */
  38
  39 #include "nsComplexBreaker.h"
  40
  41 #include <pango/pango-break.h>
  42 #include "nsUTF8Utils.h"
  43 #include "nsString.h"
  44 #include "nsTArray.h"
  45
  46 void
  47 NS_GetComplexLineBreaks(const PRUnichar* aText, PRUint32 aLength,
  48                         PRPackedBool* aBreakBefore)
  49 {
  50   NS_ASSERTION(aText, "aText shouldn't be null");
  51
  52   memset(aBreakBefore, PR_FALSE, aLength * sizeof(PRPackedBool));
  53
  54   nsAutoTArray<PangoLogAttr, 2000> attrBuffer;
  55   if (!attrBuffer.AppendElements(aLength + 1))
  56     return;
  57
  58   NS_ConvertUTF16toUTF8 aUTF8(aText, aLength);
  59
  60   const gchar* p = aUTF8.Data();
  61   const gchar* end = p + aUTF8.Length();
  62   PRUint32     u16Offset = 0;
  63
  64   static PangoLanguage* language = pango_language_from_string("en");
  65
  66   while (p < end)
  67   {
  68     PangoLogAttr* attr = attrBuffer.Elements();
  69     pango_get_log_attrs(p, end - p, -1, language, attr, attrBuffer.Length());
  70
  71     while (p < end)
  72     {
  73       aBreakBefore[u16Offset] = attr->is_line_break;
  74       if (NS_IS_LOW_SURROGATE(aText[u16Offset]))
  75         aBreakBefore[++u16Offset] = PR_FALSE; // Skip high surrogate
  76       ++u16Offset;
  77
  78       PRUint32 ch = UTF8CharEnumerator::NextChar(&p, end);
  79       ++attr;
  80
  81       if (ch == 0) {
  82         // pango_break (pango 1.16.2) only analyses text before the
  83         // first NUL (but sets one extra attr). Workaround loop to call
  84         // pango_break again to analyse after the NUL is done somewhere else
  85         // (gfx/thebes/src/gfxPangoFonts.cpp: SetupClusterBoundaries()).
  86         // So, we do the same here for pango_get_log_attrs.
  87         break;
  88       }
  89     }
  90   }
  91 }
  92