Make SkDeque::back faster & inline
http://codereview.appspot.com/6462073/ git-svn-id: http://skia.googlecode.com/svn/trunk@5149 2bbb7eff-a529-9590-31e7-b0007b416f81
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robertphillips@google.com
parent
1b3ce47c7b
commit
63ae1cfb10
@ -12,6 +12,17 @@
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#include "SkTypes.h"
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/*
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* The deque class works by blindly creating memory space of a specified element
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* size. It manages the memory as a doubly linked list of blocks each of which
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* can contain multiple elements. Pushes and pops add/remove blocks from the
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* beginning/end of the list as necessary while each block tracks the used
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* portion of its memory.
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* One behavior to be aware of is that the pops do not immediately remove an
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* empty block from the beginning/end of the list (Presumably so push/pop pairs
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* on the block boundaries don't cause thrashing). This can result in the first/
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* last element not residing in the first/last block.
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*/
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class SK_API SkDeque : SkNoncopyable {
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public:
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/**
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@ -26,8 +37,8 @@ public:
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int count() const { return fCount; }
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size_t elemSize() const { return fElemSize; }
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const void* front() const;
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const void* back() const;
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const void* front() const { return fFront; }
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const void* back() const { return fBack; }
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void* front() {
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return (void*)((const SkDeque*)this)->front();
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@ -37,6 +48,10 @@ public:
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return (void*)((const SkDeque*)this)->back();
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}
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/**
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* push_front and push_back return a pointer to the memory space
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* for the new element
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*/
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void* push_front();
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void* push_back();
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@ -100,8 +115,11 @@ private:
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// allow unit test to call numBlocksAllocated
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friend class DequeUnitTestHelper;
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Block* fFront;
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Block* fBack;
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void* fFront;
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void* fBack;
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Block* fFrontBlock;
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Block* fBackBlock;
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size_t fElemSize;
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void* fInitialStorage;
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int fCount; // number of elements in the deque
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@ -565,6 +565,7 @@ void SkClipStack::clipDevRect(const SkRect& rect, SkRegion::Op op, bool doAA) {
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int32_t genID = GetNextGenID();
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// Use reverse iterator instead of back because Rect path may need previous
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SkDeque::Iter iter(fDeque, SkDeque::Iter::kBack_IterStart);
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Rec* rec = (Rec*) iter.prev();
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@ -648,8 +649,7 @@ void SkClipStack::clipDevPath(const SkPath& path, SkRegion::Op op, bool doAA) {
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void SkClipStack::clipEmpty() {
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SkDeque::Iter iter(fDeque, SkDeque::Iter::kBack_IterStart);
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Rec* rec = (Rec*) iter.prev();
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Rec* rec = (Rec*) fDeque.back();
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if (rec && rec->canBeIntersectedInPlace(fSaveCount, SkRegion::kIntersect_Op)) {
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switch (rec->fState) {
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@ -32,6 +32,7 @@ SkDeque::SkDeque(size_t elemSize, int allocCount)
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, fCount(0)
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, fAllocCount(allocCount) {
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SkASSERT(allocCount >= 1);
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fFrontBlock = fBackBlock = NULL;
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fFront = fBack = NULL;
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}
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@ -44,16 +45,17 @@ SkDeque::SkDeque(size_t elemSize, void* storage, size_t storageSize, int allocCo
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SkASSERT(allocCount >= 1);
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if (storageSize >= sizeof(Block) + elemSize) {
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fFront = (Block*)storage;
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fFront->init(storageSize);
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fFrontBlock = (Block*)storage;
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fFrontBlock->init(storageSize);
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} else {
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fFront = NULL;
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fFrontBlock = NULL;
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}
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fBack = fFront;
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fBackBlock = fFrontBlock;
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fFront = fBack = NULL;
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}
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SkDeque::~SkDeque() {
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Block* head = fFront;
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Block* head = fFrontBlock;
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Block* initialHead = (Block*)fInitialStorage;
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while (head) {
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@ -65,47 +67,15 @@ SkDeque::~SkDeque() {
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}
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}
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const void* SkDeque::front() const {
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Block* front = fFront;
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if (NULL == front) {
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return NULL;
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}
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if (NULL == front->fBegin) {
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front = front->fNext;
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if (NULL == front) {
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return NULL;
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}
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}
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SkASSERT(front->fBegin);
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return front->fBegin;
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}
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const void* SkDeque::back() const {
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Block* back = fBack;
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if (NULL == back) {
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return NULL;
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}
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if (NULL == back->fEnd) { // marked as deleted
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back = back->fPrev;
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if (NULL == back) {
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return NULL;
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}
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}
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SkASSERT(back->fEnd);
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return back->fEnd - fElemSize;
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}
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void* SkDeque::push_front() {
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fCount += 1;
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if (NULL == fFront) {
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fFront = this->allocateBlock(fAllocCount);
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fBack = fFront; // update our linklist
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if (NULL == fFrontBlock) {
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fFrontBlock = this->allocateBlock(fAllocCount);
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fBackBlock = fFrontBlock; // update our linklist
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}
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Block* first = fFront;
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Block* first = fFrontBlock;
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char* begin;
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if (NULL == first->fBegin) {
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@ -117,26 +87,35 @@ void* SkDeque::push_front() {
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if (begin < first->start()) { // no more room in this chunk
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// should we alloc more as we accumulate more elements?
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first = this->allocateBlock(fAllocCount);
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first->fNext = fFront;
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fFront->fPrev = first;
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fFront = first;
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first->fNext = fFrontBlock;
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fFrontBlock->fPrev = first;
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fFrontBlock = first;
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goto INIT_CHUNK;
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}
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}
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first->fBegin = begin;
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if (NULL == fFront) {
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SkASSERT(NULL == fBack);
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fFront = fBack = begin;
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} else {
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SkASSERT(NULL != fBack);
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fFront = begin;
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}
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return begin;
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}
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void* SkDeque::push_back() {
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fCount += 1;
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if (NULL == fBack) {
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fBack = this->allocateBlock(fAllocCount);
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fFront = fBack; // update our linklist
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if (NULL == fBackBlock) {
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fBackBlock = this->allocateBlock(fAllocCount);
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fFrontBlock = fBackBlock; // update our linklist
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}
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Block* last = fBack;
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Block* last = fBackBlock;
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char* end;
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if (NULL == last->fBegin) {
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@ -148,40 +127,58 @@ void* SkDeque::push_back() {
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if (end > last->fStop) { // no more room in this chunk
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// should we alloc more as we accumulate more elements?
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last = this->allocateBlock(fAllocCount);
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last->fPrev = fBack;
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fBack->fNext = last;
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fBack = last;
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last->fPrev = fBackBlock;
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fBackBlock->fNext = last;
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fBackBlock = last;
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goto INIT_CHUNK;
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}
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}
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last->fEnd = end;
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return end - fElemSize;
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end -= fElemSize;
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if (NULL == fBack) {
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SkASSERT(NULL == fFront);
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fFront = fBack = end;
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} else {
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SkASSERT(NULL != fFront);
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fBack = end;
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}
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return end;
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}
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void SkDeque::pop_front() {
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SkASSERT(fCount > 0);
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fCount -= 1;
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Block* first = fFront;
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Block* first = fFrontBlock;
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SkASSERT(first != NULL);
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if (first->fBegin == NULL) { // we were marked empty from before
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first = first->fNext;
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first->fPrev = NULL;
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this->freeBlock(fFront);
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fFront = first;
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this->freeBlock(fFrontBlock);
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fFrontBlock = first;
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SkASSERT(first != NULL); // else we popped too far
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}
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char* begin = first->fBegin + fElemSize;
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SkASSERT(begin <= first->fEnd);
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if (begin < fFront->fEnd) {
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if (begin < fFrontBlock->fEnd) {
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first->fBegin = begin;
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SkASSERT(NULL != first->fBegin);
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fFront = first->fBegin;
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} else {
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first->fBegin = first->fEnd = NULL; // mark as empty
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if (NULL == first->fNext) {
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fFront = fBack = NULL;
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} else {
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SkASSERT(NULL != first->fNext->fBegin);
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fFront = first->fNext->fBegin;
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}
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}
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}
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@ -189,15 +186,15 @@ void SkDeque::pop_back() {
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SkASSERT(fCount > 0);
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fCount -= 1;
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Block* last = fBack;
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Block* last = fBackBlock;
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SkASSERT(last != NULL);
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if (last->fEnd == NULL) { // we were marked empty from before
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last = last->fPrev;
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last->fNext = NULL;
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this->freeBlock(fBack);
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fBack = last;
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this->freeBlock(fBackBlock);
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fBackBlock = last;
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SkASSERT(last != NULL); // else we popped too far
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}
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@ -206,15 +203,23 @@ void SkDeque::pop_back() {
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if (end > last->fBegin) {
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last->fEnd = end;
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SkASSERT(NULL != last->fEnd);
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fBack = last->fEnd - fElemSize;
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} else {
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last->fBegin = last->fEnd = NULL; // mark as empty
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if (NULL == last->fPrev) {
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fFront = fBack = NULL;
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} else {
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SkASSERT(NULL != last->fPrev->fEnd);
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fBack = last->fPrev->fEnd - fElemSize;
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}
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}
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}
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int SkDeque::numBlocksAllocated() const {
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int numBlocks = 0;
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for (const Block* temp = fFront; temp; temp = temp->fNext) {
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for (const Block* temp = fFrontBlock; temp; temp = temp->fNext) {
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++numBlocks;
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}
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@ -287,14 +292,14 @@ void SkDeque::Iter::reset(const SkDeque& d, IterStart startLoc) {
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if (kFront_IterStart == startLoc) {
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// initialize the iterator to start at the front
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fCurBlock = d.fFront;
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fCurBlock = d.fFrontBlock;
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while (NULL != fCurBlock && NULL == fCurBlock->fBegin) {
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fCurBlock = fCurBlock->fNext;
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}
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fPos = fCurBlock ? fCurBlock->fBegin : NULL;
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} else {
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// initialize the iterator to start at the back
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fCurBlock = d.fBack;
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fCurBlock = d.fBackBlock;
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while (NULL != fCurBlock && NULL == fCurBlock->fEnd) {
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fCurBlock = fCurBlock->fPrev;
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}
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