Move the GlyphCache to use a hash table instead of doing its own ad-hoc

src/core/SkGlyphCache.cpp

Index: src/core/SkGlyphCache.cpp
diff --git a/src/core/SkGlyphCache.cpp b/src/core/SkGlyphCache.cpp
index ec342275cc6f3c6354eb60d0c16eeebcb8d0767b..26e1a4bddc7b41ced6b42d7f962f8bf91bde6f61 100755
--- a/src/core/SkGlyphCache.cpp
+++ b/src/core/SkGlyphCache.cpp
@@ -40,17 +40,6 @@ static SkGlyphCache_Globals& getGlobals() {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-#ifdef SK_GLYPHCACHE_TRACK_HASH_STATS
-    #define RecordHashSuccess()             fHashHitCount += 1
-    #define RecordHashCollisionIf(pred)     do { if (pred) fHashMissCount += 1; } while (0)
-#else
-    #define RecordHashSuccess()             (void)0
-    #define RecordHashCollisionIf(pred)     (void)0
-#endif
-#define RecordHashCollision() RecordHashCollisionIf(true)
-
-///////////////////////////////////////////////////////////////////////////////
-
 // so we don't grow our arrays a lot
 #define kMinGlyphCount      16
 #define kMinGlyphImageSize  (16*2)
@@ -67,58 +56,13 @@ SkGlyphCache::SkGlyphCache(SkTypeface* typeface, const SkDescriptor* desc, SkSca
     fDesc = desc->copy();
     fScalerContext->getFontMetrics(&fFontMetrics);
 
-    // Create the sentinel SkGlyph.
-    SkGlyph* sentinel = fGlyphArray.insert(0);
-    sentinel->initGlyphFromCombinedID(SkGlyph::kImpossibleID);
-
-    // Initialize all index to zero which points to the sentinel SkGlyph.
-    memset(fGlyphHash, 0x00, sizeof(fGlyphHash));
-
     fMemoryUsed = sizeof(*this);
 
-    fGlyphArray.setReserve(kMinGlyphCount);
-
     fAuxProcList = NULL;
-
-#ifdef SK_GLYPHCACHE_TRACK_HASH_STATS
-    fHashHitCount = fHashMissCount = 0;
-#endif
 }
 
 SkGlyphCache::~SkGlyphCache() {
-#if 0
-    {
-        size_t ptrMem = fGlyphArray.count() * sizeof(SkGlyph*);
-        size_t glyphAlloc = fGlyphAlloc.totalCapacity();
-        size_t glyphHashUsed = 0;
-        size_t uniHashUsed = 0;
-        for (int i = 0; i < kHashCount; ++i) {
-            glyphHashUsed += fGlyphHash[i] ? sizeof(fGlyphHash[0]) : 0;
-            uniHashUsed += fCharToGlyphHash[i].fID != 0xFFFFFFFF ? sizeof(fCharToGlyphHash[0]) : 0;
-        }
-        size_t glyphUsed = fGlyphArray.count() * sizeof(SkGlyph);
-        size_t imageUsed = 0;
-        for (int i = 0; i < fGlyphArray.count(); ++i) {
-            const SkGlyph& g = *fGlyphArray[i];
-            if (g.fImage) {
-                imageUsed += g.fHeight * g.rowBytes();
-            }
-        }
-
-        SkDebugf("glyphPtrArray,%zu, Alloc,%zu, imageUsed,%zu, glyphUsed,%zu, glyphHashAlloc,%zu, glyphHashUsed,%zu, unicharHashAlloc,%zu, unicharHashUsed,%zu\n",
-                 ptrMem, glyphAlloc, imageUsed, glyphUsed, sizeof(fGlyphHash), glyphHashUsed, sizeof(CharGlyphRec) * kHashCount, uniHashUsed);
-
-    }
-#endif
-    SkGlyph*   gptr = fGlyphArray.begin();
-    SkGlyph*   stop = fGlyphArray.end();
-    while (gptr < stop) {
-        SkPath* path = gptr->fPath;
-        if (path) {
-            SkDELETE(path);
-        }
-        gptr += 1;
-    }
+    fGlyphMap.foreach([](SkGlyph* g) { if (g->fPath != NULL) { SkDELETE(g->fPath); } } );
     SkDescriptor::Free(fDesc);
     SkDELETE(fScalerContext);
     this->invokeAndRemoveAuxProcs();
@@ -132,28 +76,13 @@ SkGlyphCache::CharGlyphRec* SkGlyphCache::getCharGlyphRec(uint32_t id) {
         // an fID value that will not match any id.
         for (int i = 0; i <kHashCount; ++i) {
             fCharToGlyphHash[i].fID = SkGlyph::kImpossibleID;
-            fCharToGlyphHash[i].fGlyphIndex = 0;
+            fCharToGlyphHash[i].fCombinedID = 0;
         }
     }
 
     return &fCharToGlyphHash[ID2HashIndex(id)];
 }
 
-void SkGlyphCache::adjustCaches(int insertion_index) {
-    for (int i = 0; i < kHashCount; ++i) {
-        if (fGlyphHash[i] >= SkToU16(insertion_index)) {
-            fGlyphHash[i] += 1;
-        }
-    }
-    if (fCharToGlyphHash.get() != NULL) {
-        for (int i = 0; i < kHashCount; ++i) {
-            if (fCharToGlyphHash[i].fGlyphIndex >= SkToU16(insertion_index)) {
-                fCharToGlyphHash[i].fGlyphIndex += 1;
-            }
-        }
-    }
-}
-
 ///////////////////////////////////////////////////////////////////////////////
 
 #ifdef SK_DEBUG
@@ -168,7 +97,7 @@ uint16_t SkGlyphCache::unicharToGlyph(SkUnichar charCode) {
     const CharGlyphRec& rec = *this->getCharGlyphRec(id);
 
     if (rec.fID == id) {
-        return fGlyphArray[rec.fGlyphIndex].getGlyphID();
+        return SkGlyph::ID2Code(rec.fCombinedID);
     } else {
         return fScalerContext->charToGlyphID(charCode);
     }
@@ -223,37 +152,24 @@ const SkGlyph& SkGlyphCache::getGlyphIDMetrics(uint16_t glyphID, SkFixed x, SkFi
 SkGlyph* SkGlyphCache::lookupByChar(SkUnichar charCode, MetricsType type, SkFixed x, SkFixed y) {
     uint32_t id = SkGlyph::MakeID(charCode, x, y);
     CharGlyphRec* rec = this->getCharGlyphRec(id);
-    SkGlyph* glyph;
     if (rec->fID != id) {
-        RecordHashCollisionIf(glyph_index != SkGlyph::kImpossibleID);
         // this ID is based on the UniChar
         rec->fID = id;
         // this ID is based on the glyph index
-        id = SkGlyph::MakeID(fScalerContext->charToGlyphID(charCode), x, y);
-        rec->fGlyphIndex = this->lookupMetrics(id, type);
-        glyph = &fGlyphArray[rec->fGlyphIndex];
+        int32_t combinedID = SkGlyph::MakeID(fScalerContext->charToGlyphID(charCode), x, y);
+        rec->fCombinedID = combinedID;
+        return this->lookupByCombinedID(combinedID, type);
     } else {
-        RecordHashSuccess();
-        glyph = &fGlyphArray[rec->fGlyphIndex];
-        if (type == kFull_MetricsType && glyph->isJustAdvance()) {
-            fScalerContext->getMetrics(glyph);
-        }
+        return this->lookupByCombinedID(rec->fCombinedID, type);
     }
-    return glyph;
 }
 
 SkGlyph* SkGlyphCache::lookupByCombinedID(uint32_t id, MetricsType type) {
-    uint32_t hash_index = ID2HashIndex(id);
-    uint16_t glyph_index = fGlyphHash[hash_index];
-    SkGlyph* glyph = &fGlyphArray[glyph_index];
-
-    if (glyph->fID != id) {
-        RecordHashCollisionIf(glyph_index != SkGlyph::kImpossibleID);
-        glyph_index = this->lookupMetrics(id, type);
-        fGlyphHash[hash_index] = glyph_index;
-        glyph = &fGlyphArray[glyph_index];
+    SkGlyph* glyph = fGlyphMap.find(id);
+
+    if (NULL == glyph) {
+        glyph = this->lookupMetrics(id, type);
     } else {
-        RecordHashSuccess();
         if (type == kFull_MetricsType && glyph->isJustAdvance()) {
            fScalerContext->getMetrics(glyph);
         }
@@ -261,55 +177,25 @@ SkGlyph* SkGlyphCache::lookupByCombinedID(uint32_t id, MetricsType type) {
     return glyph;
 }
 
-uint16_t SkGlyphCache::lookupMetrics(uint32_t id, MetricsType mtype) {
-    SkASSERT(id != SkGlyph::kImpossibleID);
-    // Count is always greater than 0 because of the sentinel.
-    // The fGlyphArray cache is in descending order, so that the sentinel with a value of ~0 is
-    // always at index 0.
-    SkGlyph* gptr = fGlyphArray.begin();
-    int lo = 0;
-    int hi = fGlyphArray.count() - 1;
-    while (lo < hi) {
-        int mid = (hi + lo) >> 1;
-        if (gptr[mid].fID > id) {
-            lo = mid + 1;
-        } else {
-            hi = mid;
-        }
-    }
-
-    uint16_t glyph_index = hi;
-    SkGlyph* glyph = &gptr[glyph_index];
-    if (glyph->fID == id) {
-        if (kFull_MetricsType == mtype && glyph->isJustAdvance()) {
-            fScalerContext->getMetrics(glyph);
-        }
-        SkASSERT(glyph->fID != SkGlyph::kImpossibleID);
-        return glyph_index;
-    }
-
-    // check if we need to bump hi before falling though to the allocator
-    if (glyph->fID > id) {
-        glyph_index += 1;
-    }
-
-    // Not found, but hi contains the index of the insertion point of the new glyph.
+SkGlyph* SkGlyphCache::lookupMetrics(uint32_t id, MetricsType mtype) {
     fMemoryUsed += sizeof(SkGlyph);
 
-    this->adjustCaches(glyph_index);
-
-    glyph = fGlyphArray.insert(glyph_index);
-    glyph->initGlyphFromCombinedID(id);
+    SkGlyph* glyphPtr;
+    {
+        SkGlyph glyph;
+        glyph.initGlyphFromCombinedID(id);
+        glyphPtr = fGlyphMap.set(glyph);
+    }
 
     if (kJustAdvance_MetricsType == mtype) {
-        fScalerContext->getAdvance(glyph);
+        fScalerContext->getAdvance(glyphPtr);
     } else {
         SkASSERT(kFull_MetricsType == mtype);
-        fScalerContext->getMetrics(glyph);
+        fScalerContext->getMetrics(glyphPtr);
     }
 
-    SkASSERT(glyph->fID != SkGlyph::kImpossibleID);
-    return glyph_index;
+    SkASSERT(glyphPtr->fID != SkGlyph::kImpossibleID);
+    return glyphPtr;
 }
 
 const void* SkGlyphCache::findImage(const SkGlyph& glyph) {
@@ -359,11 +245,7 @@ void SkGlyphCache::dump() const {
                matrix[SkMatrix::kMScaleX], matrix[SkMatrix::kMSkewX],
                matrix[SkMatrix::kMSkewY], matrix[SkMatrix::kMScaleY],
                rec.fLumBits & 0xFF, rec.fDeviceGamma, rec.fPaintGamma, rec.fContrast,
-               fGlyphArray.count());
-#ifdef SK_GLYPHCACHE_TRACK_HASH_STATS
-    const int sum = SkTMax(fHashHitCount + fHashMissCount, 1);   // avoid divide-by-zero
-    msg.appendf(" hash:%2d\n", 100 * fHashHitCount / sum);
-#endif
+               fGlyphMap.count());
     SkDebugf("%s\n", msg.c_str());
 }
 
@@ -533,21 +415,9 @@ void SkGlyphCache::Dump() {
     SkDebugf("SkGlyphCache strikes:%d memory:%d\n",
              globals.getCacheCountUsed(), (int)globals.getTotalMemoryUsed());
 
-#ifdef SK_GLYPHCACHE_TRACK_HASH_STATS
-    int hitCount = 0;
-    int missCount = 0;
-#endif
-
     for (cache = globals.internalGetHead(); cache != NULL; cache = cache->fNext) {
-#ifdef SK_GLYPHCACHE_TRACK_HASH_STATS
-        hitCount += cache->fHashHitCount;
-        missCount += cache->fHashMissCount;
-#endif
         cache->dump();
     }
-#ifdef SK_GLYPHCACHE_TRACK_HASH_STATS
-    SkDebugf("Hash hit percent:%2d\n", 100 * hitCount / (hitCount + missCount));
-#endif
 }
 
 ///////////////////////////////////////////////////////////////////////////////