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/*
* Copyright 2010 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkBitmapCache.h"
struct SkBitmapCache::Entry {
Entry* fPrev;
Entry* fNext;
void* fBuffer;
size_t fSize;
SkBitmap fBitmap;
Entry(const void* buffer, size_t size, const SkBitmap& bm)
: fPrev(NULL),
fNext(NULL),
fBitmap(bm) {
fBuffer = sk_malloc_throw(size);
fSize = size;
memcpy(fBuffer, buffer, size);
}
~Entry() { sk_free(fBuffer); }
bool equals(const void* buffer, size_t size) const {
return (fSize == size) && !memcmp(fBuffer, buffer, size);
}
};
SkBitmapCache::SkBitmapCache(int max) : fMaxEntries(max) {
fEntryCount = 0;
fHead = fTail = NULL;
this->validate();
}
SkBitmapCache::~SkBitmapCache() {
this->validate();
Entry* entry = fHead;
while (entry) {
Entry* next = entry->fNext;
delete entry;
entry = next;
}
}
SkBitmapCache::Entry* SkBitmapCache::detach(Entry* entry) const {
if (entry->fPrev) {
SkASSERT(fHead != entry);
entry->fPrev->fNext = entry->fNext;
} else {
SkASSERT(fHead == entry);
fHead = entry->fNext;
}
if (entry->fNext) {
SkASSERT(fTail != entry);
entry->fNext->fPrev = entry->fPrev;
} else {
SkASSERT(fTail == entry);
fTail = entry->fPrev;
}
return entry;
}
void SkBitmapCache::attachToHead(Entry* entry) const {
entry->fPrev = NULL;
entry->fNext = fHead;
if (fHead) {
fHead->fPrev = entry;
} else {
fTail = entry;
}
fHead = entry;
}
bool SkBitmapCache::find(const void* buffer, size_t size, SkBitmap* bm) const {
AutoValidate av(this);
Entry* entry = fHead;
while (entry) {
if (entry->equals(buffer, size)) {
if (bm) {
*bm = entry->fBitmap;
}
// move to the head of our list, so we purge it last
this->detach(entry);
this->attachToHead(entry);
return true;
}
entry = entry->fNext;
}
return false;
}
void SkBitmapCache::add(const void* buffer, size_t len, const SkBitmap& bm) {
AutoValidate av(this);
if (fEntryCount == fMaxEntries) {
SkASSERT(fTail);
delete this->detach(fTail);
fEntryCount -= 1;
}
Entry* entry = new Entry(buffer, len, bm);
this->attachToHead(entry);
fEntryCount += 1;
}
///////////////////////////////////////////////////////////////////////////////
#ifdef SK_DEBUG
void SkBitmapCache::validate() const {
SkASSERT(fEntryCount >= 0 && fEntryCount <= fMaxEntries);
if (fEntryCount > 0) {
SkASSERT(NULL == fHead->fPrev);
SkASSERT(NULL == fTail->fNext);
if (fEntryCount == 1) {
SkASSERT(fHead == fTail);
} else {
SkASSERT(fHead != fTail);
}
Entry* entry = fHead;
int count = 0;
while (entry) {
count += 1;
entry = entry->fNext;
}
SkASSERT(count == fEntryCount);
entry = fTail;
while (entry) {
count -= 1;
entry = entry->fPrev;
}
SkASSERT(0 == count);
} else {
SkASSERT(NULL == fHead);
SkASSERT(NULL == fTail);
}
}
#endif