WebCore/GlyphWidthMap.h

   1 /*
   2  * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   8  * 1.  Redistributions of source code must retain the above copyright
   9  *     notice, this list of conditions and the following disclaimer.
  10  * 2.  Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  14  *     its contributors may be used to endorse or promote products derived
  15  *     from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #ifndef GlyphWidthMap_h
  30 #define GlyphWidthMap_h
  31
  32 #include <wtf/unicode/Unicode.h>
  33 #include <wtf/Noncopyable.h>
  34 #include <wtf/HashMap.h>
  35
  36 namespace WebCore {
  37
  38 typedef unsigned short Glyph;
  39
  40 const float cGlyphWidthUnknown = -1;
  41
  42 class GlyphWidthMap : Noncopyable {
  43 public:
  44     GlyphWidthMap() : m_filledPrimaryPage(false), m_pages(0) {}
  45     ~GlyphWidthMap() { if (m_pages) { deleteAllValues(*m_pages); delete m_pages; } }
  46
  47     float widthForGlyph(Glyph);
  48     void setWidthForGlyph(Glyph, float);
  49
  50 private:
  51     struct GlyphWidthPage {
  52         static const size_t size = 256; // Usually covers Latin-1 in a single page.
  53         float m_widths[size];
  54
  55         float widthForGlyph(Glyph g) const { return m_widths[g % size]; }
  56         void setWidthForGlyph(Glyph g, float w)
  57         {
  58             setWidthForIndex(g % size, w);
  59         }
  60         void setWidthForIndex(unsigned index, float w)
  61         {
  62             m_widths[index] = w;
  63         }
  64     };
  65
  66     GlyphWidthPage* locatePage(unsigned page);
  67
  68     bool m_filledPrimaryPage;
  69     GlyphWidthPage m_primaryPage; // We optimize for the page that contains glyph indices 0-255.
  70     HashMap<int, GlyphWidthPage*>* m_pages;
  71 };
  72
  73 }
  74 #endif