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/*
* Copyright (C) 2006, 2007, 2008 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 GlyphPageTreeNode_h
#define GlyphPageTreeNode_h
#include <string.h>
#include <wtf/HashMap.h>
#include <wtf/PassRefPtr.h>
#include <wtf/RefCounted.h>
#include <wtf/unicode/Unicode.h>
#ifndef NDEBUG
void showGlyphPageTrees();
void showGlyphPageTree(unsigned pageNumber);
#endif
namespace WebCore {
class FontData;
class GlyphPageTreeNode;
class SimpleFontData;
typedef unsigned short Glyph;
// Holds the glyph index and the corresponding SimpleFontData information for a given
// character.
struct GlyphData {
GlyphData(Glyph g = 0, const SimpleFontData* f = 0)
: glyph(g)
, fontData(f)
{
}
Glyph glyph;
const SimpleFontData* fontData;
};
// A GlyphPage contains a fixed-size set of GlyphData mappings for a contiguous
// range of characters in the Unicode code space. GlyphPages are indexed
// starting from 0 and incrementing for each 256 glyphs.
//
// One page may actually include glyphs from other fonts if the characters are
// missing in the primary font. It is owned by exactly one GlyphPageTreeNode,
// although multiple nodes may reference it as their "page" if they are supposed
// to be overriding the parent's node, but provide no additional information.
class GlyphPage : public RefCounted<GlyphPage> {
public:
static PassRefPtr<GlyphPage> create(GlyphPageTreeNode* owner)
{
return adoptRef(new GlyphPage(owner));
}
static const size_t size = 256; // Covers Latin-1 in a single page.
unsigned indexForCharacter(UChar32 c) const { return c % size; }
GlyphData glyphDataForCharacter(UChar32 c) const
{
unsigned index = indexForCharacter(c);
return GlyphData(m_glyphs[index], m_glyphFontData[index]);
}
GlyphData glyphDataForIndex(unsigned index) const
{
ASSERT(index < size);
return GlyphData(m_glyphs[index], m_glyphFontData[index]);
}
Glyph glyphAt(unsigned index) const
{
ASSERT(index < size);
return m_glyphs[index];
}
const SimpleFontData* fontDataForCharacter(UChar32 c) const
{
return m_glyphFontData[indexForCharacter(c)];
}
void setGlyphDataForCharacter(UChar32 c, Glyph g, const SimpleFontData* f)
{
setGlyphDataForIndex(indexForCharacter(c), g, f);
}
void setGlyphDataForIndex(unsigned index, Glyph g, const SimpleFontData* f)
{
ASSERT(index < size);
m_glyphs[index] = g;
m_glyphFontData[index] = f;
}
void setGlyphDataForIndex(unsigned index, const GlyphData& glyphData)
{
setGlyphDataForIndex(index, glyphData.glyph, glyphData.fontData);
}
void copyFrom(const GlyphPage& other)
{
memcpy(m_glyphs, other.m_glyphs, sizeof(m_glyphs));
memcpy(m_glyphFontData, other.m_glyphFontData, sizeof(m_glyphFontData));
}
void clear()
{
memset(m_glyphs, 0, sizeof(m_glyphs));
memset(m_glyphFontData, 0, sizeof(m_glyphFontData));
}
GlyphPageTreeNode* owner() const { return m_owner; }
// Implemented by the platform.
bool fill(unsigned offset, unsigned length, UChar* characterBuffer, unsigned bufferLength, const SimpleFontData*);
private:
GlyphPage(GlyphPageTreeNode* owner)
: m_owner(owner)
{
}
// Separate arrays, rather than array of GlyphData, to save space.
Glyph m_glyphs[size];
const SimpleFontData* m_glyphFontData[size];
GlyphPageTreeNode* m_owner;
};
// The glyph page tree is a data structure that maps (FontData, glyph page number)
// to a GlyphPage. Level 0 (the "root") is special. There is one root
// GlyphPageTreeNode for each glyph page number. The roots do not have a
// GlyphPage associated with them, and their initializePage() function is never
// called to fill the glyphs.
//
// Each root node maps a FontData pointer to another GlyphPageTreeNode at
// level 1 (the "root child") that stores the actual glyphs for a specific font data.
// These nodes will only have a GlyphPage if they have glyphs for that range.
//
// Levels greater than one correspond to subsequent levels of the fallback list
// for that font. These levels override their parent's page of glyphs by
// filling in holes with the new font (thus making a more complete page).
//
// A NULL FontData pointer corresponds to the system fallback
// font. It is tracked separately from the regular pages and overrides so that
// the glyph pages do not get polluted with these last-resort glyphs. The
// system fallback page is not populated at construction like the other pages,
// but on demand for each glyph, because the system may need to use different
// fallback fonts for each. This lazy population is done by the Font.
class GlyphPageTreeNode {
public:
GlyphPageTreeNode()
: m_parent(0)
, m_level(0)
, m_isSystemFallback(false)
, m_customFontCount(0)
, m_systemFallbackChild(0)
#ifndef NDEBUG
, m_pageNumber(0)
#endif
{
}
~GlyphPageTreeNode();
static HashMap<int, GlyphPageTreeNode*>* roots;
static GlyphPageTreeNode* pageZeroRoot;
static GlyphPageTreeNode* getRootChild(const FontData* fontData, unsigned pageNumber)
{
return getRoot(pageNumber)->getChild(fontData, pageNumber);
}
static void pruneTreeCustomFontData(const FontData*);
static void pruneTreeFontData(const SimpleFontData*);
void pruneCustomFontData(const FontData*);
void pruneFontData(const SimpleFontData*, unsigned level = 0);
#if PLATFORM(ANDROID)
static void resetRoots();
void resetChildren();
#endif
GlyphPageTreeNode* parent() const { return m_parent; }
GlyphPageTreeNode* getChild(const FontData*, unsigned pageNumber);
// Returns a page of glyphs (or NULL if there are no glyphs in this page's character range).
GlyphPage* page() const { return m_page.get(); }
// Returns the level of this node. See class-level comment.
unsigned level() const { return m_level; }
// The system fallback font has special rules (see above).
bool isSystemFallback() const { return m_isSystemFallback; }
static size_t treeGlyphPageCount();
size_t pageCount() const;
private:
static GlyphPageTreeNode* getRoot(unsigned pageNumber);
void initializePage(const FontData*, unsigned pageNumber);
#ifndef NDEBUG
void showSubtree();
#endif
GlyphPageTreeNode* m_parent;
RefPtr<GlyphPage> m_page;
unsigned m_level : 31;
bool m_isSystemFallback : 1;
unsigned m_customFontCount;
HashMap<const FontData*, GlyphPageTreeNode*> m_children;
GlyphPageTreeNode* m_systemFallbackChild;
#ifndef NDEBUG
unsigned m_pageNumber;
friend void ::showGlyphPageTree(unsigned pageNumber);
#endif
};
} // namespace WebCore
#endif // GlyphPageTreeNode_h
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