src/ports/SkFontHost_android.cpp - platform/external/skia - Git at Google

 /* libs/graphics/ports/SkFontHost_android.cpp
 **
 ** Copyright 2006, The Android Open Source Project
 **
 ** Licensed under the Apache License, Version 2.0 (the "License");
 ** you may not use this file except in compliance with the License.
 ** You may obtain a copy of the License at
 **
 **     http://www.apache.org/licenses/LICENSE-2.0
 **
 ** Unless required by applicable law or agreed to in writing, software
 ** distributed under the License is distributed on an "AS IS" BASIS,
 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 ** See the License for the specific language governing permissions and
 ** limitations under the License.
 */

 #include "SkFontHost.h"
 #include "SkDescriptor.h"
 #include "SkMMapStream.h"
 #include "SkPaint.h"
 #include "SkString.h"
 #include "SkStream.h"
 #include "SkThread.h"
 #include "SkTSearch.h"
 #include <stdio.h>

 #define FONT_CACHE_MEMORY_BUDGET    (768 * 1024)

 #ifndef SK_FONT_FILE_PREFIX
     #define SK_FONT_FILE_PREFIX          "/fonts/"
 #endif

 SkTypeface::Style find_name_and_attributes(SkStream* stream, SkString* name,
                                            bool* isFixedWidth);

 static void GetFullPathForSysFonts(SkString* full, const char name[]) {
     full->set(getenv("ANDROID_ROOT"));
     full->append(SK_FONT_FILE_PREFIX);
     full->append(name);
 }

 ///////////////////////////////////////////////////////////////////////////////

 struct FamilyRec;

 /*  This guy holds a mapping of a name -> family, used for looking up fonts.
     Since it is stored in a stretchy array that doesn't preserve object
     semantics, we don't use constructor/destructors, but just have explicit
     helpers to manage our internal bookkeeping.
 */
 struct NameFamilyPair {
     const char* fName;      // we own this
     FamilyRec*  fFamily;    // we don't own this, we just reference it

     void construct(const char name[], FamilyRec* family) {
         fName = strdup(name);
         fFamily = family;   // we don't own this, so just record the referene
     }

     void destruct() {
         free((char*)fName);
         // we don't own family, so just ignore our reference
     }
 };

 // we use atomic_inc to grow this for each typeface we create
 static int32_t gUniqueFontID;

 // this is the mutex that protects these globals
 static SkMutex gFamilyMutex;
 static FamilyRec* gFamilyHead;
 static SkTDArray<NameFamilyPair> gNameList;

 struct FamilyRec {
     FamilyRec*  fPrev;
     FamilyRec*  fNext;
     SkTypeface* fFaces[4];

     FamilyRec()
     {
         static FamilyRec* tail = 0;
         if (!gFamilyHead) {
             gFamilyHead = this;
         }
         fPrev = tail;
         fNext = 0;
         memset(fFaces, 0, sizeof(fFaces));
         if (tail) {
             tail->fNext = this;
         }
         tail = this;
 //        SkDebugf("FamilyRec::FamilyRec(%p) fPrev=%p fNext=%p fFaces=[%p,%p,%p,%p]",
 //                 this, fPrev, fNext, fFaces[0], fFaces[1], fFaces[2], fFaces[3]);
     }
 };

 // Styles are spread across a family. Fallback fonts, as a whole, are treated as one family
 static SkTypeface* find_best_face(const FamilyRec* family,
                                   SkTypeface::Style style) {
     SkTypeface* const* faces = family->fFaces;

     if (faces[style] != NULL) { // exact match
         return faces[style];
     }
     // look for a matching bold
     style = (SkTypeface::Style)(style ^ SkTypeface::kItalic);
     if (faces[style] != NULL) {
         return faces[style];
     }
     // look for the plain
     if (faces[SkTypeface::kNormal] != NULL) {
         return faces[SkTypeface::kNormal];
     }
     // look for anything
     for (int i = 0; i < 4; i++) {
         if (faces[i] != NULL) {
             return faces[i];
         }
     }
     // should never get here, since the faces list should not be empty
     SkASSERT(!"faces list is empty");
     return NULL;
 }

 static FamilyRec* find_family(const SkTypeface* member) {
     FamilyRec* curr = gFamilyHead;
     while (curr != NULL) {
         for (int i = 0; i < 4; i++) {
             if (curr->fFaces[i] == member) {
                 return curr;
             }
         }
         curr = curr->fNext;
     }
     return NULL;
 }

 /*  Returns the matching typeface, or NULL. If a typeface is found, its refcnt
     is not modified.
  */
 static SkTypeface* find_from_uniqueID(uint32_t uniqueID) {
     FamilyRec* curr = gFamilyHead;
     while (curr != NULL) {
         for (int i = 0; i < 4; i++) {
             SkTypeface* face = curr->fFaces[i];
             if (face != NULL && face->uniqueID() == uniqueID) {
                 return face;
             }
         }
         curr = curr->fNext;
     }
     return NULL;
 }

 /*  Remove reference to this face from its family. If the resulting family
     is empty (has no faces), return that family, otherwise return NULL
 */
 static FamilyRec* remove_from_family(const SkTypeface* face) {
     FamilyRec* family = find_family(face);
     if (family) {
         SkASSERT(family->fFaces[face->style()] == face);
         family->fFaces[face->style()] = NULL;

         for (int i = 0; i < 4; i++) {
             if (family->fFaces[i] != NULL) {    // family is non-empty
                 return NULL;
             }
         }
     } else {
 //        SkDebugf("remove_from_family(%p) face not found", face);
     }
     return family;  // return the empty family
 }

 static void detach_and_delete_family(FamilyRec* family) {
     FamilyRec* prev = family->fPrev;
     FamilyRec* next = family->fNext;

     if (family == gFamilyHead) {
         gFamilyHead = next;
     }
     if (prev) {
         prev->fNext = next;
     }
     if (next) {
         next->fPrev = prev;
     }
     SkDELETE(family);
 }

 static SkTypeface* find_typeface(const char name[], SkTypeface::Style style) {
     NameFamilyPair* list = gNameList.begin();
     int             count = gNameList.count();

     int index = SkStrLCSearch(&list[0].fName, count, name, sizeof(list[0]));

     if (index >= 0) {
         return find_best_face(list[index].fFamily, style);
     }
     return NULL;
 }

 static SkTypeface* find_typeface(const SkTypeface* familyMember,
                                  SkTypeface::Style style) {
     const FamilyRec* family = find_family(familyMember);
     return family ? find_best_face(family, style) : NULL;
 }

 static void add_name(const char name[], FamilyRec* family) {
     SkAutoAsciiToLC tolc(name);
     name = tolc.lc();

     NameFamilyPair* list = gNameList.begin();
     int             count = gNameList.count();

     int index = SkStrLCSearch(&list[0].fName, count, name, sizeof(list[0]));

     if (index < 0) {
         list = gNameList.insert(~index);
         list->construct(name, family);
     }
 }

 static void remove_from_names(FamilyRec* emptyFamily)
 {
 #ifdef SK_DEBUG
     for (int i = 0; i < 4; i++) {
         SkASSERT(emptyFamily->fFaces[i] == NULL);
     }
 #endif

     SkTDArray<NameFamilyPair>& list = gNameList;

     // must go backwards when removing
     for (int i = list.count() - 1; i >= 0; --i) {
         NameFamilyPair* pair = &list[i];
         if (pair->fFamily == emptyFamily) {
             pair->destruct();
             list.remove(i);
         }
     }
 }

 ///////////////////////////////////////////////////////////////////////////////

 class FamilyTypeface : public SkTypeface {
 public:
     FamilyTypeface(Style style, bool sysFont, SkTypeface* familyMember,
                    bool isFixedWidth)
     : SkTypeface(style, sk_atomic_inc(&gUniqueFontID) + 1, isFixedWidth) {
         fIsSysFont = sysFont;

         SkAutoMutexAcquire  ac(gFamilyMutex);

         FamilyRec* rec = NULL;
         if (familyMember) {
             rec = find_family(familyMember);
             SkASSERT(rec);
         } else {
             rec = SkNEW(FamilyRec);
         }
         rec->fFaces[style] = this;
     }

     virtual ~FamilyTypeface() {
         SkAutoMutexAcquire  ac(gFamilyMutex);

         // remove us from our family. If the family is now empty, we return
         // that and then remove that family from the name list
         FamilyRec* family = remove_from_family(this);
         if (NULL != family) {
             remove_from_names(family);
             detach_and_delete_family(family);
         }
     }

     bool isSysFont() const { return fIsSysFont; }

     virtual SkStream* openStream() = 0;
     virtual const char* getUniqueString() const = 0;
     virtual const char* getFilePath() const = 0;

 private:
     bool    fIsSysFont;

     typedef SkTypeface INHERITED;
 };

 ///////////////////////////////////////////////////////////////////////////////

 class StreamTypeface : public FamilyTypeface {
 public:
     StreamTypeface(Style style, bool sysFont, SkTypeface* familyMember,
                    SkStream* stream, bool isFixedWidth)
     : INHERITED(style, sysFont, familyMember, isFixedWidth) {
         SkASSERT(stream);
         stream->ref();
         fStream = stream;
     }
     virtual ~StreamTypeface() {
         fStream->unref();
     }

     // overrides
     virtual SkStream* openStream() {
         // we just ref our existing stream, since the caller will call unref()
         // when they are through
         fStream->ref();
         // must rewind each time, since the caller assumes a "new" stream
         fStream->rewind();
         return fStream;
     }
     virtual const char* getUniqueString() const { return NULL; }
     virtual const char* getFilePath() const { return NULL; }

 private:
     SkStream* fStream;

     typedef FamilyTypeface INHERITED;
 };

 class FileTypeface : public FamilyTypeface {
 public:
     FileTypeface(Style style, bool sysFont, SkTypeface* familyMember,
                  const char path[], bool isFixedWidth)
     : INHERITED(style, sysFont, familyMember, isFixedWidth) {
         SkString fullpath;

         if (sysFont) {
             GetFullPathForSysFonts(&fullpath, path);
             path = fullpath.c_str();
         }
         fPath.set(path);
     }

     // overrides
     virtual SkStream* openStream() {
         SkStream* stream = SkNEW_ARGS(SkMMAPStream, (fPath.c_str()));

         // check for failure
         if (stream->getLength() <= 0) {
             SkDELETE(stream);
             // maybe MMAP isn't supported. try FILE
             stream = SkNEW_ARGS(SkFILEStream, (fPath.c_str()));
             if (stream->getLength() <= 0) {
                 SkDELETE(stream);
                 stream = NULL;
             }
         }
         return stream;
     }
     virtual const char* getUniqueString() const {
         const char* str = strrchr(fPath.c_str(), '/');
         if (str) {
             str += 1;   // skip the '/'
         }
         return str;
     }
     virtual const char* getFilePath() const {
         return fPath.c_str();
     }

 private:
     SkString fPath;

     typedef FamilyTypeface INHERITED;
 };

 ///////////////////////////////////////////////////////////////////////////////
 ///////////////////////////////////////////////////////////////////////////////

 static bool get_name_and_style(const char path[], SkString* name,
                                SkTypeface::Style* style, bool* isFixedWidth) {
     SkString        fullpath;
     GetFullPathForSysFonts(&fullpath, path);

     SkMMAPStream stream(fullpath.c_str());
     if (stream.getLength() > 0) {
         *style = find_name_and_attributes(&stream, name, isFixedWidth);
         return true;
     }
     else {
         SkFILEStream stream(fullpath.c_str());
         if (stream.getLength() > 0) {
             *style = find_name_and_attributes(&stream, name, isFixedWidth);
             return true;
         }
     }
     SkDebugf("get_name_and_style() failed to open <%s> as a font\n", fullpath.c_str());
     return false;
 }

 // used to record our notion of the pre-existing fonts
 struct FontInitRec {
     const char*         fFileName;
     const char* const*  fNames;     // null-terminated list
 };

 static const char* gSansNames[] = {
     "sans-serif", "arial", "helvetica", "tahoma", "verdana", NULL
 };

 static const char* gSerifNames[] = {
     "serif", "times", "times new roman", "palatino", "georgia", "baskerville",
     "goudy", "fantasy", "cursive", "ITC Stone Serif", NULL
 };

 static const char* gMonoNames[] = {
     "monospace", "courier", "courier new", "monaco", NULL
 };

 // deliberately empty, but we use the address to identify fallback fonts
 static const char* gFBNames[] = { NULL };

 /*  Fonts must be grouped by family, with the first font in a family having the
     list of names (even if that list is empty), and the following members having
     null for the list. The names list must be NULL-terminated
 */
 static const FontInitRec gSystemFonts[] = {
     { "DroidSans.ttf",              gSansNames  },
     { "DroidSans-Bold.ttf",         NULL        },
     { "DroidSerif-Regular.ttf",     gSerifNames },
     { "DroidSerif-Bold.ttf",        NULL        },
     { "DroidSerif-Italic.ttf",      NULL        },
     { "DroidSerif-BoldItalic.ttf",  NULL        },
     { "DroidSansMono.ttf",          gMonoNames  },
     /*  These are optional, and can be ignored if not found in the file system.
         These are appended to gFallbackFonts[] as they are seen, so we list
         them in the order we want them to be accessed by NextLogicalFont().
      */
     { "DroidSansArabic.ttf",        gFBNames    },
     { "DroidSansHebrew-Regular.ttf",gFBNames    },
     { "DroidSansHebrew-Bold.ttf",   NULL        },
     { "DroidSansThai.ttf",          gFBNames    },
     { "MTLmr3m.ttf",                gFBNames    }, // Motoya Japanese Font
     { "MTLc3m.ttf",                 gFBNames    }, // Motoya Japanese Font
     { "DroidSansJapanese.ttf",      gFBNames    },
     { "DroidSansEthiopic-Regular.ttf",gFBNames  },
     { "DroidSansEthiopic-Bold.ttf", NULL        },
     { "DroidSansFallback.ttf",      gFBNames    }
 };

 #define DEFAULT_NAMES   gSansNames

 // these globals are assigned (once) by load_system_fonts()
 static FamilyRec* gDefaultFamily;
 static SkTypeface* gDefaultNormal;

 /*  Fallback fonts are a segment of the linked list that starts at gFamilyHead,
     configured by load_system_fonts().
  */
 static FamilyRec* gFallbackHead;

 /*  Called once (ensured by the sentinel check at the beginning of our body).
     Initializes all the globals, and register the system fonts.
  */
 static void load_system_fonts() {
     // check if we've already be called
     if (NULL != gDefaultNormal) {
         return;
     }

     const FontInitRec* rec = gSystemFonts;
     SkTypeface* firstInFamily = NULL;

     for (size_t i = 0; i < SK_ARRAY_COUNT(gSystemFonts); i++) {
         // if we're the first in a new family, clear firstInFamily
         if (rec[i].fNames != NULL) {
             firstInFamily = NULL;
         }

         bool isFixedWidth;
         SkString name;
         SkTypeface::Style style;

         // we expect all the fonts, except the "fallback" fonts
         // after one fallback is received, all the rest are fallbacks, too
         if (!get_name_and_style(rec[i].fFileName, &name, &style, &isFixedWidth)) {
             continue;
         }

         SkTypeface* tf = SkNEW_ARGS(FileTypeface,
                                     (style,
                                      true,  // system-font (cannot delete)
                                      firstInFamily, // what family to join
                                      rec[i].fFileName,
                                      isFixedWidth) // filename
                                     );

 //        SkDebugf("load_system_fonts() %s, %d, %d, %d\n",
 //                                 rec[i].fFileName, style, firstInFamily, tf->uniqueID());

         if (rec[i].fNames != NULL) {
             firstInFamily = tf;
             FamilyRec* family = find_family(tf);
             const char* const* names = rec[i].fNames;

             // record the default family if this is it
             if (names == DEFAULT_NAMES) {
                 gDefaultFamily = family;
             }
             // add the names to map to this family
             while (*names) {
                 add_name(*names, family);
                 names += 1;
             }
             // see if this is one of our fallback fonts
             if (rec[i].fNames == gFBNames) {
                 if (!gFallbackHead) {
                     // record the first of the fallback families
                     gFallbackHead = family;
                 }
             }

         }
     }

     // do this after all fonts are loaded. This is our default font, and it
     // acts as a sentinel so we only execute load_system_fonts() once
     gDefaultNormal = find_best_face(gDefaultFamily, SkTypeface::kNormal);
 }

 ///////////////////////////////////////////////////////////////////////////////

 void SkFontHost::Serialize(const SkTypeface* face, SkWStream* stream) {
     const char* name = ((FamilyTypeface*)face)->getUniqueString();

     stream->write8((uint8_t)face->style());

     if (NULL == name || 0 == *name) {
         stream->writePackedUInt(0);
 //        SkDebugf("--- fonthost serialize null\n");
     } else {
         uint32_t len = strlen(name);
         stream->writePackedUInt(len);
         stream->write(name, len);
 //      SkDebugf("--- fonthost serialize <%s> %d\n", name, face->style());
     }
 }

 SkTypeface* SkFontHost::Deserialize(SkStream* stream) {
     load_system_fonts();

     int style = stream->readU8();

     int len = stream->readPackedUInt();
     if (len > 0) {
         SkString str;
         str.resize(len);
         stream->read(str.writable_str(), len);

         const FontInitRec* rec = gSystemFonts;
         for (size_t i = 0; i < SK_ARRAY_COUNT(gSystemFonts); i++) {
             if (strcmp(rec[i].fFileName, str.c_str()) == 0) {
                 // backup until we hit the fNames
                 for (int j = i; j >= 0; --j) {
                     if (rec[j].fNames != NULL) {
                         return SkFontHost::CreateTypeface(NULL,
                                     rec[j].fNames[0], NULL, 0, (SkTypeface::Style)style);
                     }
                 }
             }
         }
     }
     return NULL;
 }

 ///////////////////////////////////////////////////////////////////////////////

 SkTypeface* SkFontHost::CreateTypeface(const SkTypeface* familyFace,
                                        const char familyName[],
                                        const void* data, size_t bytelength,
                                        SkTypeface::Style style) {
     load_system_fonts();

     SkAutoMutexAcquire  ac(gFamilyMutex);

     // clip to legal style bits
     style = (SkTypeface::Style)(style & SkTypeface::kBoldItalic);

     SkTypeface* tf = NULL;

     if (NULL != familyFace) {
         tf = find_typeface(familyFace, style);
 //        SkDebugf("SkFontHost::CreateTypeface find_typeface for familyFace returns %p", tf);
     } else if (NULL != familyName) {
         tf = find_typeface(familyName, style);
 //        SkDebugf("SkFontHost::CreateTypeface find_typeface for familyName returns %p", tf);
     }

     if (NULL == tf) {
         tf = find_best_face(gDefaultFamily, style);
 //        SkDebugf("SkFontHost::CreateTypeface find_best_face for gDefaultFamily returns %p", tf);
     }

     // we ref(), since the symantic is to return a new instance
     tf->ref();
     return tf;
 }

 bool SkFontHost::ValidFontID(uint32_t fontID) {
     SkAutoMutexAcquire  ac(gFamilyMutex);

     return find_from_uniqueID(fontID) != NULL;
 }

 SkStream* SkFontHost::OpenStream(uint32_t fontID) {
     SkAutoMutexAcquire  ac(gFamilyMutex);

     FamilyTypeface* tf = (FamilyTypeface*)find_from_uniqueID(fontID);
     SkStream* stream = tf ? tf->openStream() : NULL;

     if (stream && stream->getLength() == 0) {
         stream->unref();
         stream = NULL;
     }
     return stream;
 }

 size_t SkFontHost::GetFileName(SkFontID fontID, char path[], size_t length,
                                int32_t* index) {
     SkAutoMutexAcquire  ac(gFamilyMutex);

     FamilyTypeface* tf = (FamilyTypeface*)find_from_uniqueID(fontID);
     const char* src = tf ? tf->getFilePath() : NULL;

     if (src) {
         size_t size = strlen(src);
         if (path) {
             memcpy(path, src, SkMin32(size, length));
         }
         if (index) {
             *index = 0; // we don't have collections (yet)
         }
         return size;
     } else {
         return 0;
     }
 }

 SkFontID SkFontHost::NextLogicalFont(SkFontID currFontID, SkFontID origFontID) {
     load_system_fonts();

     /*  First see if fontID is already one of our fallbacks. If so, return
         its successor. If fontID is not in our list, then return the first one
         in our list. Note: list is zero-terminated, and returning zero means
         we have no more fonts to use for fallbacks.
      */

     SkTypeface* origTypeface = find_from_uniqueID(origFontID);
     SkTypeface::Style origStyle = origTypeface ? origTypeface->style() : SkTypeface::kNormal;

     FamilyRec* family = gFallbackHead;
     while (family) {
         SkTypeface* typeface = find_best_face(family, origStyle);
         family = family->fNext;
         if (typeface && typeface->uniqueID() == currFontID) {
             if (family) {
                 return find_best_face(family, origStyle)->uniqueID();
             } else {
                 return 0;
             }
         }
     }

     if (gFallbackHead) {
         return find_best_face(gFallbackHead, origStyle)->uniqueID();
     }
     return 0;
 }

 ///////////////////////////////////////////////////////////////////////////////

 SkTypeface* SkFontHost::CreateTypefaceFromStream(SkStream* stream) {
     if (NULL == stream || stream->getLength() <= 0) {
         return NULL;
     }

     bool isFixedWidth;
     SkString name;
     SkTypeface::Style style = find_name_and_attributes(stream, &name, &isFixedWidth);

     if (!name.isEmpty()) {
         return SkNEW_ARGS(StreamTypeface, (style, false, NULL, stream, isFixedWidth));
     } else {
         return NULL;
     }
 }

 SkTypeface* SkFontHost::CreateTypefaceFromFile(const char path[]) {
     SkStream* stream = SkNEW_ARGS(SkMMAPStream, (path));
     SkTypeface* face = SkFontHost::CreateTypefaceFromStream(stream);
     // since we created the stream, we let go of our ref() here
     stream->unref();
     return face;
 }

 ///////////////////////////////////////////////////////////////////////////////

 size_t SkFontHost::ShouldPurgeFontCache(size_t sizeAllocatedSoFar) {
     if (sizeAllocatedSoFar > FONT_CACHE_MEMORY_BUDGET)
         return sizeAllocatedSoFar - FONT_CACHE_MEMORY_BUDGET;
     else
         return 0;   // nothing to do
 }
	/* libs/graphics/ports/SkFontHost_android.cpp
	**
	** Copyright 2006, The Android Open Source Project
	**
	** Licensed under the Apache License, Version 2.0 (the "License");
	** you may not use this file except in compliance with the License.
	** You may obtain a copy of the License at
	**
	** http://www.apache.org/licenses/LICENSE-2.0
	**
	** Unless required by applicable law or agreed to in writing, software
	** distributed under the License is distributed on an "AS IS" BASIS,
	** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	** See the License for the specific language governing permissions and
	** limitations under the License.
	*/

	#include "SkFontHost.h"
	#include "SkDescriptor.h"
	#include "SkMMapStream.h"
	#include "SkPaint.h"
	#include "SkString.h"
	#include "SkStream.h"
	#include "SkThread.h"
	#include "SkTSearch.h"
	#include <stdio.h>

	#define FONT_CACHE_MEMORY_BUDGET (768 * 1024)

	#ifndef SK_FONT_FILE_PREFIX
	#define SK_FONT_FILE_PREFIX "/fonts/"
	#endif

	SkTypeface::Style find_name_and_attributes(SkStream* stream, SkString* name,
	bool* isFixedWidth);

	static void GetFullPathForSysFonts(SkString* full, const char name[]) {
	full->set(getenv("ANDROID_ROOT"));
	full->append(SK_FONT_FILE_PREFIX);
	full->append(name);
	}

	///////////////////////////////////////////////////////////////////////////////

	struct FamilyRec;

	/* This guy holds a mapping of a name -> family, used for looking up fonts.
	Since it is stored in a stretchy array that doesn't preserve object
	semantics, we don't use constructor/destructors, but just have explicit
	helpers to manage our internal bookkeeping.
	*/
	struct NameFamilyPair {
	const char* fName; // we own this
	FamilyRec* fFamily; // we don't own this, we just reference it

	void construct(const char name[], FamilyRec* family) {
	fName = strdup(name);
	fFamily = family; // we don't own this, so just record the referene
	}

	void destruct() {
	free((char*)fName);
	// we don't own family, so just ignore our reference
	}
	};

	// we use atomic_inc to grow this for each typeface we create
	static int32_t gUniqueFontID;

	// this is the mutex that protects these globals
	static SkMutex gFamilyMutex;
	static FamilyRec* gFamilyHead;
	static SkTDArray<NameFamilyPair> gNameList;

	struct FamilyRec {
	FamilyRec* fPrev;
	FamilyRec* fNext;
	SkTypeface* fFaces[4];

	FamilyRec()
	{
	static FamilyRec* tail = 0;
	if (!gFamilyHead) {
	gFamilyHead = this;
	}
	fPrev = tail;
	fNext = 0;
	memset(fFaces, 0, sizeof(fFaces));
	if (tail) {
	tail->fNext = this;
	}
	tail = this;
	// SkDebugf("FamilyRec::FamilyRec(%p) fPrev=%p fNext=%p fFaces=[%p,%p,%p,%p]",
	// this, fPrev, fNext, fFaces[0], fFaces[1], fFaces[2], fFaces[3]);
	}
	};

	// Styles are spread across a family. Fallback fonts, as a whole, are treated as one family
	static SkTypeface* find_best_face(const FamilyRec* family,
	SkTypeface::Style style) {
	SkTypeface* const* faces = family->fFaces;

	if (faces[style] != NULL) { // exact match
	return faces[style];
	}
	// look for a matching bold
	style = (SkTypeface::Style)(style ^ SkTypeface::kItalic);
	if (faces[style] != NULL) {
	return faces[style];
	}
	// look for the plain
	if (faces[SkTypeface::kNormal] != NULL) {
	return faces[SkTypeface::kNormal];
	}
	// look for anything
	for (int i = 0; i < 4; i++) {
	if (faces[i] != NULL) {
	return faces[i];
	}
	}
	// should never get here, since the faces list should not be empty
	SkASSERT(!"faces list is empty");
	return NULL;
	}

	static FamilyRec* find_family(const SkTypeface* member) {
	FamilyRec* curr = gFamilyHead;
	while (curr != NULL) {
	for (int i = 0; i < 4; i++) {
	if (curr->fFaces[i] == member) {
	return curr;
	}
	}
	curr = curr->fNext;
	}
	return NULL;
	}

	/* Returns the matching typeface, or NULL. If a typeface is found, its refcnt
	is not modified.
	*/
	static SkTypeface* find_from_uniqueID(uint32_t uniqueID) {
	FamilyRec* curr = gFamilyHead;
	while (curr != NULL) {
	for (int i = 0; i < 4; i++) {
	SkTypeface* face = curr->fFaces[i];
	if (face != NULL && face->uniqueID() == uniqueID) {
	return face;
	}
	}
	curr = curr->fNext;
	}
	return NULL;
	}

	/* Remove reference to this face from its family. If the resulting family
	is empty (has no faces), return that family, otherwise return NULL
	*/
	static FamilyRec* remove_from_family(const SkTypeface* face) {
	FamilyRec* family = find_family(face);
	if (family) {
	SkASSERT(family->fFaces[face->style()] == face);
	family->fFaces[face->style()] = NULL;

	for (int i = 0; i < 4; i++) {
	if (family->fFaces[i] != NULL) { // family is non-empty
	return NULL;
	}
	}
	} else {
	// SkDebugf("remove_from_family(%p) face not found", face);
	}
	return family; // return the empty family
	}

	static void detach_and_delete_family(FamilyRec* family) {
	FamilyRec* prev = family->fPrev;
	FamilyRec* next = family->fNext;

	if (family == gFamilyHead) {
	gFamilyHead = next;
	}
	if (prev) {
	prev->fNext = next;
	}
	if (next) {
	next->fPrev = prev;
	}
	SkDELETE(family);
	}

	static SkTypeface* find_typeface(const char name[], SkTypeface::Style style) {
	NameFamilyPair* list = gNameList.begin();
	int count = gNameList.count();

	int index = SkStrLCSearch(&list[0].fName, count, name, sizeof(list[0]));

	if (index >= 0) {
	return find_best_face(list[index].fFamily, style);
	}
	return NULL;
	}

	static SkTypeface* find_typeface(const SkTypeface* familyMember,
	SkTypeface::Style style) {
	const FamilyRec* family = find_family(familyMember);
	return family ? find_best_face(family, style) : NULL;
	}

	static void add_name(const char name[], FamilyRec* family) {
	SkAutoAsciiToLC tolc(name);
	name = tolc.lc();

	NameFamilyPair* list = gNameList.begin();
	int count = gNameList.count();

	int index = SkStrLCSearch(&list[0].fName, count, name, sizeof(list[0]));

	if (index < 0) {
	list = gNameList.insert(~index);
	list->construct(name, family);
	}
	}

	static void remove_from_names(FamilyRec* emptyFamily)
	{
	#ifdef SK_DEBUG
	for (int i = 0; i < 4; i++) {
	SkASSERT(emptyFamily->fFaces[i] == NULL);
	}
	#endif

	SkTDArray<NameFamilyPair>& list = gNameList;

	// must go backwards when removing
	for (int i = list.count() - 1; i >= 0; --i) {
	NameFamilyPair* pair = &list[i];
	if (pair->fFamily == emptyFamily) {
	pair->destruct();
	list.remove(i);
	}
	}
	}

	///////////////////////////////////////////////////////////////////////////////

	class FamilyTypeface : public SkTypeface {
	public:
	FamilyTypeface(Style style, bool sysFont, SkTypeface* familyMember,
	bool isFixedWidth)
	: SkTypeface(style, sk_atomic_inc(&gUniqueFontID) + 1, isFixedWidth) {
	fIsSysFont = sysFont;

	SkAutoMutexAcquire ac(gFamilyMutex);

	FamilyRec* rec = NULL;
	if (familyMember) {
	rec = find_family(familyMember);
	SkASSERT(rec);
	} else {
	rec = SkNEW(FamilyRec);
	}
	rec->fFaces[style] = this;
	}

	virtual ~FamilyTypeface() {
	SkAutoMutexAcquire ac(gFamilyMutex);

	// remove us from our family. If the family is now empty, we return
	// that and then remove that family from the name list
	FamilyRec* family = remove_from_family(this);
	if (NULL != family) {
	remove_from_names(family);
	detach_and_delete_family(family);
	}
	}

	bool isSysFont() const { return fIsSysFont; }

	virtual SkStream* openStream() = 0;
	virtual const char* getUniqueString() const = 0;
	virtual const char* getFilePath() const = 0;

	private:
	bool fIsSysFont;

	typedef SkTypeface INHERITED;
	};

	///////////////////////////////////////////////////////////////////////////////

	class StreamTypeface : public FamilyTypeface {
	public:
	StreamTypeface(Style style, bool sysFont, SkTypeface* familyMember,
	SkStream* stream, bool isFixedWidth)
	: INHERITED(style, sysFont, familyMember, isFixedWidth) {
	SkASSERT(stream);
	stream->ref();
	fStream = stream;
	}
	virtual ~StreamTypeface() {
	fStream->unref();
	}

	// overrides
	virtual SkStream* openStream() {
	// we just ref our existing stream, since the caller will call unref()
	// when they are through
	fStream->ref();
	// must rewind each time, since the caller assumes a "new" stream
	fStream->rewind();
	return fStream;
	}
	virtual const char* getUniqueString() const { return NULL; }
	virtual const char* getFilePath() const { return NULL; }

	private:
	SkStream* fStream;

	typedef FamilyTypeface INHERITED;
	};

	class FileTypeface : public FamilyTypeface {
	public:
	FileTypeface(Style style, bool sysFont, SkTypeface* familyMember,
	const char path[], bool isFixedWidth)
	: INHERITED(style, sysFont, familyMember, isFixedWidth) {
	SkString fullpath;

	if (sysFont) {
	GetFullPathForSysFonts(&fullpath, path);
	path = fullpath.c_str();
	}
	fPath.set(path);
	}

	// overrides
	virtual SkStream* openStream() {
	SkStream* stream = SkNEW_ARGS(SkMMAPStream, (fPath.c_str()));

	// check for failure
	if (stream->getLength() <= 0) {
	SkDELETE(stream);
	// maybe MMAP isn't supported. try FILE
	stream = SkNEW_ARGS(SkFILEStream, (fPath.c_str()));
	if (stream->getLength() <= 0) {
	SkDELETE(stream);
	stream = NULL;
	}
	}
	return stream;
	}
	virtual const char* getUniqueString() const {
	const char* str = strrchr(fPath.c_str(), '/');
	if (str) {
	str += 1; // skip the '/'
	}
	return str;
	}
	virtual const char* getFilePath() const {
	return fPath.c_str();
	}

	private:
	SkString fPath;

	typedef FamilyTypeface INHERITED;
	};

	///////////////////////////////////////////////////////////////////////////////
	///////////////////////////////////////////////////////////////////////////////

	static bool get_name_and_style(const char path[], SkString* name,
	SkTypeface::Style* style, bool* isFixedWidth) {
	SkString fullpath;
	GetFullPathForSysFonts(&fullpath, path);

	SkMMAPStream stream(fullpath.c_str());
	if (stream.getLength() > 0) {
	*style = find_name_and_attributes(&stream, name, isFixedWidth);
	return true;
	}
	else {
	SkFILEStream stream(fullpath.c_str());
	if (stream.getLength() > 0) {
	*style = find_name_and_attributes(&stream, name, isFixedWidth);
	return true;
	}
	}
	SkDebugf("get_name_and_style() failed to open <%s> as a font\n", fullpath.c_str());
	return false;
	}

	// used to record our notion of the pre-existing fonts
	struct FontInitRec {
	const char* fFileName;
	const char* const* fNames; // null-terminated list
	};

	static const char* gSansNames[] = {
	"sans-serif", "arial", "helvetica", "tahoma", "verdana", NULL
	};

	static const char* gSerifNames[] = {
	"serif", "times", "times new roman", "palatino", "georgia", "baskerville",
	"goudy", "fantasy", "cursive", "ITC Stone Serif", NULL
	};

	static const char* gMonoNames[] = {
	"monospace", "courier", "courier new", "monaco", NULL
	};

	// deliberately empty, but we use the address to identify fallback fonts
	static const char* gFBNames[] = { NULL };

	/* Fonts must be grouped by family, with the first font in a family having the
	list of names (even if that list is empty), and the following members having
	null for the list. The names list must be NULL-terminated
	*/
	static const FontInitRec gSystemFonts[] = {
	{ "DroidSans.ttf", gSansNames },
	{ "DroidSans-Bold.ttf", NULL },
	{ "DroidSerif-Regular.ttf", gSerifNames },
	{ "DroidSerif-Bold.ttf", NULL },
	{ "DroidSerif-Italic.ttf", NULL },
	{ "DroidSerif-BoldItalic.ttf", NULL },
	{ "DroidSansMono.ttf", gMonoNames },
	/* These are optional, and can be ignored if not found in the file system.
	These are appended to gFallbackFonts[] as they are seen, so we list
	them in the order we want them to be accessed by NextLogicalFont().
	*/
	{ "DroidSansArabic.ttf", gFBNames },
	{ "DroidSansHebrew-Regular.ttf",gFBNames },
	{ "DroidSansHebrew-Bold.ttf", NULL },
	{ "DroidSansThai.ttf", gFBNames },
	{ "MTLmr3m.ttf", gFBNames }, // Motoya Japanese Font
	{ "MTLc3m.ttf", gFBNames }, // Motoya Japanese Font
	{ "DroidSansJapanese.ttf", gFBNames },
	{ "DroidSansEthiopic-Regular.ttf",gFBNames },
	{ "DroidSansEthiopic-Bold.ttf", NULL },
	{ "DroidSansFallback.ttf", gFBNames }
	};

	#define DEFAULT_NAMES gSansNames

	// these globals are assigned (once) by load_system_fonts()
	static FamilyRec* gDefaultFamily;
	static SkTypeface* gDefaultNormal;

	/* Fallback fonts are a segment of the linked list that starts at gFamilyHead,
	configured by load_system_fonts().
	*/
	static FamilyRec* gFallbackHead;

	/* Called once (ensured by the sentinel check at the beginning of our body).
	Initializes all the globals, and register the system fonts.
	*/
	static void load_system_fonts() {
	// check if we've already be called
	if (NULL != gDefaultNormal) {
	return;
	}

	const FontInitRec* rec = gSystemFonts;
	SkTypeface* firstInFamily = NULL;

	for (size_t i = 0; i < SK_ARRAY_COUNT(gSystemFonts); i++) {
	// if we're the first in a new family, clear firstInFamily
	if (rec[i].fNames != NULL) {
	firstInFamily = NULL;
	}

	bool isFixedWidth;
	SkString name;
	SkTypeface::Style style;

	// we expect all the fonts, except the "fallback" fonts
	// after one fallback is received, all the rest are fallbacks, too
	if (!get_name_and_style(rec[i].fFileName, &name, &style, &isFixedWidth)) {
	continue;
	}

	SkTypeface* tf = SkNEW_ARGS(FileTypeface,
	(style,
	true, // system-font (cannot delete)
	firstInFamily, // what family to join
	rec[i].fFileName,
	isFixedWidth) // filename
	);

	// SkDebugf("load_system_fonts() %s, %d, %d, %d\n",
	// rec[i].fFileName, style, firstInFamily, tf->uniqueID());

	if (rec[i].fNames != NULL) {
	firstInFamily = tf;
	FamilyRec* family = find_family(tf);
	const char* const* names = rec[i].fNames;

	// record the default family if this is it
	if (names == DEFAULT_NAMES) {
	gDefaultFamily = family;
	}
	// add the names to map to this family
	while (*names) {
	add_name(*names, family);
	names += 1;
	}
	// see if this is one of our fallback fonts
	if (rec[i].fNames == gFBNames) {
	if (!gFallbackHead) {
	// record the first of the fallback families
	gFallbackHead = family;
	}
	}

	}
	}

	// do this after all fonts are loaded. This is our default font, and it
	// acts as a sentinel so we only execute load_system_fonts() once
	gDefaultNormal = find_best_face(gDefaultFamily, SkTypeface::kNormal);
	}

	///////////////////////////////////////////////////////////////////////////////

	void SkFontHost::Serialize(const SkTypeface* face, SkWStream* stream) {
	const char* name = ((FamilyTypeface*)face)->getUniqueString();

	stream->write8((uint8_t)face->style());

	if (NULL == name \|\| 0 == *name) {
	stream->writePackedUInt(0);
	// SkDebugf("--- fonthost serialize null\n");
	} else {
	uint32_t len = strlen(name);
	stream->writePackedUInt(len);
	stream->write(name, len);
	// SkDebugf("--- fonthost serialize <%s> %d\n", name, face->style());
	}
	}

	SkTypeface* SkFontHost::Deserialize(SkStream* stream) {
	load_system_fonts();

	int style = stream->readU8();

	int len = stream->readPackedUInt();
	if (len > 0) {
	SkString str;
	str.resize(len);
	stream->read(str.writable_str(), len);

	const FontInitRec* rec = gSystemFonts;
	for (size_t i = 0; i < SK_ARRAY_COUNT(gSystemFonts); i++) {
	if (strcmp(rec[i].fFileName, str.c_str()) == 0) {
	// backup until we hit the fNames
	for (int j = i; j >= 0; --j) {
	if (rec[j].fNames != NULL) {
	return SkFontHost::CreateTypeface(NULL,
	rec[j].fNames[0], NULL, 0, (SkTypeface::Style)style);
	}
	}
	}
	}
	}
	return NULL;
	}

	///////////////////////////////////////////////////////////////////////////////

	SkTypeface* SkFontHost::CreateTypeface(const SkTypeface* familyFace,
	const char familyName[],
	const void* data, size_t bytelength,
	SkTypeface::Style style) {
	load_system_fonts();

	SkAutoMutexAcquire ac(gFamilyMutex);

	// clip to legal style bits
	style = (SkTypeface::Style)(style & SkTypeface::kBoldItalic);

	SkTypeface* tf = NULL;

	if (NULL != familyFace) {
	tf = find_typeface(familyFace, style);
	// SkDebugf("SkFontHost::CreateTypeface find_typeface for familyFace returns %p", tf);
	} else if (NULL != familyName) {
	tf = find_typeface(familyName, style);
	// SkDebugf("SkFontHost::CreateTypeface find_typeface for familyName returns %p", tf);
	}

	if (NULL == tf) {
	tf = find_best_face(gDefaultFamily, style);
	// SkDebugf("SkFontHost::CreateTypeface find_best_face for gDefaultFamily returns %p", tf);
	}

	// we ref(), since the symantic is to return a new instance
	tf->ref();
	return tf;
	}

	bool SkFontHost::ValidFontID(uint32_t fontID) {
	SkAutoMutexAcquire ac(gFamilyMutex);

	return find_from_uniqueID(fontID) != NULL;
	}

	SkStream* SkFontHost::OpenStream(uint32_t fontID) {
	SkAutoMutexAcquire ac(gFamilyMutex);

	FamilyTypeface* tf = (FamilyTypeface*)find_from_uniqueID(fontID);
	SkStream* stream = tf ? tf->openStream() : NULL;

	if (stream && stream->getLength() == 0) {
	stream->unref();
	stream = NULL;
	}
	return stream;
	}

	size_t SkFontHost::GetFileName(SkFontID fontID, char path[], size_t length,
	int32_t* index) {
	SkAutoMutexAcquire ac(gFamilyMutex);

	FamilyTypeface* tf = (FamilyTypeface*)find_from_uniqueID(fontID);
	const char* src = tf ? tf->getFilePath() : NULL;

	if (src) {
	size_t size = strlen(src);
	if (path) {
	memcpy(path, src, SkMin32(size, length));
	}
	if (index) {
	*index = 0; // we don't have collections (yet)
	}
	return size;
	} else {
	return 0;
	}
	}

	SkFontID SkFontHost::NextLogicalFont(SkFontID currFontID, SkFontID origFontID) {
	load_system_fonts();

	/* First see if fontID is already one of our fallbacks. If so, return
	its successor. If fontID is not in our list, then return the first one
	in our list. Note: list is zero-terminated, and returning zero means
	we have no more fonts to use for fallbacks.
	*/

	SkTypeface* origTypeface = find_from_uniqueID(origFontID);
	SkTypeface::Style origStyle = origTypeface ? origTypeface->style() : SkTypeface::kNormal;

	FamilyRec* family = gFallbackHead;
	while (family) {
	SkTypeface* typeface = find_best_face(family, origStyle);
	family = family->fNext;
	if (typeface && typeface->uniqueID() == currFontID) {
	if (family) {
	return find_best_face(family, origStyle)->uniqueID();
	} else {
	return 0;
	}
	}
	}

	if (gFallbackHead) {
	return find_best_face(gFallbackHead, origStyle)->uniqueID();
	}
	return 0;
	}

	///////////////////////////////////////////////////////////////////////////////

	SkTypeface* SkFontHost::CreateTypefaceFromStream(SkStream* stream) {
	if (NULL == stream \|\| stream->getLength() <= 0) {
	return NULL;
	}

	bool isFixedWidth;
	SkString name;
	SkTypeface::Style style = find_name_and_attributes(stream, &name, &isFixedWidth);

	if (!name.isEmpty()) {
	return SkNEW_ARGS(StreamTypeface, (style, false, NULL, stream, isFixedWidth));
	} else {
	return NULL;
	}
	}

	SkTypeface* SkFontHost::CreateTypefaceFromFile(const char path[]) {
	SkStream* stream = SkNEW_ARGS(SkMMAPStream, (path));
	SkTypeface* face = SkFontHost::CreateTypefaceFromStream(stream);
	// since we created the stream, we let go of our ref() here
	stream->unref();
	return face;
	}

	///////////////////////////////////////////////////////////////////////////////

	size_t SkFontHost::ShouldPurgeFontCache(size_t sizeAllocatedSoFar) {
	if (sizeAllocatedSoFar > FONT_CACHE_MEMORY_BUDGET)
	return sizeAllocatedSoFar - FONT_CACHE_MEMORY_BUDGET;
	else
	return 0; // nothing to do
	}