experimental dynamic-hash (disabled)
git-svn-id: http://skia.googlecode.com/svn/trunk@10353 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkScaledImageCache.cpp b/src/core/SkScaledImageCache.cpp
index b8590f5..147697a 100644
--- a/src/core/SkScaledImageCache.cpp
+++ b/src/core/SkScaledImageCache.cpp
@@ -14,7 +14,7 @@
#define SK_DEFAULT_IMAGE_CACHE_LIMIT (2 * 1024 * 1024)
#endif
-#if 1
+
// Implemented from en.wikipedia.org/wiki/MurmurHash.
static uint32_t compute_hash(const uint32_t data[], int count) {
uint32_t hash = 0;
@@ -40,20 +40,6 @@
return hash;
}
-#else
-static uint32_t mix(uint32_t a, uint32_t b) {
- return ((a >> 1) | (a << 31)) ^ b;
-}
-
-static uint32_t compute_hash(const uint32_t data[], int count) {
- uint32_t hash = 0;
-
- for (int i = 0; i < count; ++i) {
- hash = mix(hash, data[i]);
- }
- return hash;
-}
-#endif
struct Key {
bool init(const SkBitmap& bm, SkScalar scaleX, SkScalar scaleY) {
@@ -76,7 +62,7 @@
return true;
}
- bool operator<(const Key& other) {
+ bool operator<(const Key& other) const {
const uint32_t* a = &fGenID;
const uint32_t* b = &other.fGenID;
for (int i = 0; i < 7; ++i) {
@@ -90,7 +76,7 @@
return false;
}
- bool operator==(const Key& other) {
+ bool operator==(const Key& other) const {
const uint32_t* a = &fHash;
const uint32_t* b = &other.fHash;
for (int i = 0; i < 8; ++i) {
@@ -141,9 +127,36 @@
const SkMipMap* fMip;
};
+#include "SkTDynamicHash.h"
+
+static const Key& key_from_rec(const SkScaledImageCache::Rec& rec) {
+ return rec.fKey;
+}
+
+static uint32_t hash_from_key(const Key& key) {
+ return key.fHash;
+}
+
+static bool eq_rec_key(const SkScaledImageCache::Rec& rec, const Key& key) {
+ return rec.fKey == key;
+}
+
+class SkScaledImageCache::Hash : public SkTDynamicHash<SkScaledImageCache::Rec,
+ Key, key_from_rec, hash_from_key,
+ eq_rec_key> {};
+
+///////////////////////////////////////////////////////////////////////////////
+
+//#define USE_HASH
+
SkScaledImageCache::SkScaledImageCache(size_t byteLimit) {
fHead = NULL;
fTail = NULL;
+#ifdef USE_HASH
+ fHash = new Hash;
+#else
+ fHash = NULL;
+#endif
fBytesUsed = 0;
fByteLimit = byteLimit;
fCount = 0;
@@ -156,6 +169,7 @@
SkDELETE(rec);
rec = next;
}
+ delete fHash;
}
SkScaledImageCache::Rec* SkScaledImageCache::findAndLock(const SkBitmap& orig,
@@ -166,16 +180,23 @@
return NULL;
}
+#ifdef USE_HASH
+ Rec* rec = fHash->find(key);
+#else
Rec* rec = fHead;
while (rec != NULL) {
if (rec->fKey == key) {
- this->moveToHead(rec); // for our LRU
- rec->fLockCount += 1;
- return rec;
+ break;
}
rec = rec->fNext;
}
- return NULL;
+#endif
+
+ if (rec) {
+ this->moveToHead(rec); // for our LRU
+ rec->fLockCount += 1;
+ }
+ return rec;
}
SkScaledImageCache::ID* SkScaledImageCache::findAndLock(const SkBitmap& orig,
@@ -225,6 +246,10 @@
this->addToHead(rec);
SkASSERT(1 == rec->fLockCount);
+#ifdef USE_HASH
+ fHash->add(key, rec);
+#endif
+
// We may (now) be overbudget, so see if we need to purge something.
this->purgeAsNeeded();
return (ID*)rec;
@@ -241,6 +266,10 @@
this->addToHead(rec);
SkASSERT(1 == rec->fLockCount);
+#ifdef USE_HASH
+ fHash->add(key, rec);
+#endif
+
// We may (now) be overbudget, so see if we need to purge something.
this->purgeAsNeeded();
return (ID*)rec;
@@ -292,6 +321,10 @@
SkASSERT(used <= bytesUsed);
bytesUsed -= used;
this->detach(rec);
+#ifdef USE_HASH
+ fHash->remove(rec->fKey);
+#endif
+
SkDELETE(rec);
fCount -= 1;
}