text: /*
   * Copyright (C) 2006, 2009 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1.  Redistributions of source code must retain the above copyright
   *     notice, this list of conditions and the following disclaimer. 
   * 2.  Redistributions in binary form must reproduce the above copyright
   *     notice, this list of conditions and the following disclaimer in the
   *     documentation and/or other materials provided with the distribution. 
   * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
   *     its contributors may be used to endorse or promote products derived
   *     from this software without specific prior written permission. 
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
   * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #ifndef GlyphWidthMap_h
  #define GlyphWidthMap_h
  
  #include <wtf/HashMap.h>
  #include <wtf/OwnPtr.h>
  #include <wtf/unicode/Unicode.h>
  
  namespace WebCore {
  
  typedef unsigned short Glyph;
  
  const float cGlyphWidthUnknown = -1;
  
  class GlyphWidthMap : public Noncopyable {
  public:
      GlyphWidthMap() : m_filledPrimaryPage(false) { }
      ~GlyphWidthMap() { if (m_pages) { deleteAllValues(*m_pages); } }
  
      float widthForGlyph(Glyph glyph)
      {
          return locatePage(glyph / GlyphWidthPage::size)->widthForGlyph(glyph);
      }
  
      void setWidthForGlyph(Glyph glyph, float width)
      {
          locatePage(glyph / GlyphWidthPage::size)->setWidthForGlyph(glyph, width);
      }
  
  private:
      struct GlyphWidthPage {
          static const size_t size = 256; // Usually covers Latin-1 in a single page.
          float m_widths[size];
  
          float widthForGlyph(Glyph glyph) const { return m_widths[glyph % size]; }
          void setWidthForGlyph(Glyph glyph, float width)
          {
              setWidthForIndex(glyph % size, width);
          }
          void setWidthForIndex(unsigned index, float width)
          {
              m_widths[index] = width;
          }
      };
      
      GlyphWidthPage* locatePage(unsigned pageNumber)
      {
          if (!pageNumber && m_filledPrimaryPage)
              return &m_primaryPage;
          return locatePageSlowCase(pageNumber);
      }
  
      GlyphWidthPage* locatePageSlowCase(unsigned pageNumber);
      
      bool m_filledPrimaryPage;
      GlyphWidthPage m_primaryPage; // We optimize for the page that contains glyph indices 0-255.
      OwnPtr<HashMap<int, GlyphWidthPage*> > m_pages;
  };
  
  }
  
  #endif
  