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/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkTArray_DEFINED
#define SkTArray_DEFINED
#include <new>
#include "SkTypes.h"
#include "SkTemplates.h"
template <typename T, bool MEM_COPY = false> class SkTArray;
namespace SkTArrayExt {
template<typename T>
inline void copy(SkTArray<T, true>* self, const T* array) {
memcpy(self->fMemArray, array, self->fCount * sizeof(T));
}
template<typename T>
inline void copyAndDelete(SkTArray<T, true>* self, char* newMemArray) {
memcpy(newMemArray, self->fMemArray, self->fCount * sizeof(T));
}
template<typename T>
inline void copy(SkTArray<T, false>* self, const T* array) {
for (int i = 0; i < self->fCount; ++i) {
new (self->fItemArray + i) T(array[i]);
}
}
template<typename T>
inline void copyAndDelete(SkTArray<T, false>* self, char* newMemArray) {
for (int i = 0; i < self->fCount; ++i) {
new (newMemArray + sizeof(T) * i) T(self->fItemArray[i]);
self->fItemArray[i].~T();
}
}
}
/** When MEM_COPY is true T will be bit copied when moved.
When MEM_COPY is false, T will be copy constructed / destructed.
In all cases T's constructor will be called on allocation,
and its destructor will be called from this object's destructor.
*/
template <typename T, bool MEM_COPY> class SkTArray {
public:
/**
* Creates an empty array with no initial storage
*/
SkTArray() {
fCount = 0;
fReserveCount = gMIN_ALLOC_COUNT;
fAllocCount = 0;
fMemArray = NULL;
fPreAllocMemArray = NULL;
}
/**
* Creates an empty array that will preallocate space for reserveCount
* elements.
*/
explicit SkTArray(int reserveCount) {
this->init(NULL, 0, NULL, reserveCount);
}
/**
* Copies one array to another. The new array will be heap allocated.
*/
explicit SkTArray(const SkTArray& array) {
this->init(array.fItemArray, array.fCount, NULL, 0);
}
/**
* Creates a SkTArray by copying contents of a standard C array. The new
* array will be heap allocated. Be careful not to use this constructor
* when you really want the (void*, int) version.
*/
SkTArray(const T* array, int count) {
this->init(array, count, NULL, 0);
}
/**
* assign copy of array to this
*/
SkTArray& operator =(const SkTArray& array) {
for (int i = 0; i < fCount; ++i) {
fItemArray[i].~T();
}
fCount = 0;
checkRealloc((int)array.count());
fCount = array.count();
SkTArrayExt::copy(this, static_cast<const T*>(array.fMemArray));
return *this;
}
virtual ~SkTArray() {
for (int i = 0; i < fCount; ++i) {
fItemArray[i].~T();
}
if (fMemArray != fPreAllocMemArray) {
sk_free(fMemArray);
}
}
/**
* Resets to count() == 0
*/
void reset() { this->pop_back_n(fCount); }
/**
* Number of elements in the array.
*/
int count() const { return fCount; }
/**
* Is the array empty.
*/
bool empty() const { return !fCount; }
/**
* Adds 1 new default-constructed T value and returns in by reference. Note
* the reference only remains valid until the next call that adds or removes
* elements.
*/
T& push_back() {
checkRealloc(1);
new ((char*)fMemArray+sizeof(T)*fCount) T;
++fCount;
return fItemArray[fCount-1];
}
/**
* Version of above that uses a copy constructor to initialize the new item
*/
T& push_back(const T& t) {
checkRealloc(1);
new ((char*)fMemArray+sizeof(T)*fCount) T(t);
++fCount;
return fItemArray[fCount-1];
}
/**
* Allocates n more default T values, and returns the address of the start
* of that new range. Note: this address is only valid until the next API
* call made on the array that might add or remove elements.
*/
T* push_back_n(int n) {
SkASSERT(n >= 0);
checkRealloc(n);
for (int i = 0; i < n; ++i) {
new (fItemArray + fCount + i) T;
}
fCount += n;
return fItemArray + fCount - n;
}
/**
* Version of above that uses a copy constructor to initialize all n items
* to the same T.
*/
T* push_back_n(int n, const T& t) {
SkASSERT(n >= 0);
checkRealloc(n);
for (int i = 0; i < n; ++i) {
new (fItemArray + fCount + i) T(t);
}
fCount += n;
return fItemArray + fCount - n;
}
/**
* Version of above that uses a copy constructor to initialize the n items
* to separate T values.
*/
T* push_back_n(int n, const T t[]) {
SkASSERT(n >= 0);
checkRealloc(n);
for (int i = 0; i < n; ++i) {
new (fItemArray + fCount + i) T(t[i]);
}
fCount += n;
return fItemArray + fCount - n;
}
/**
* Removes the last element. Not safe to call when count() == 0.
*/
void pop_back() {
SkASSERT(fCount > 0);
--fCount;
fItemArray[fCount].~T();
checkRealloc(0);
}
/**
* Removes the last n elements. Not safe to call when count() < n.
*/
void pop_back_n(int n) {
SkASSERT(n >= 0);
SkASSERT(fCount >= n);
fCount -= n;
for (int i = 0; i < n; ++i) {
fItemArray[i].~T();
}
checkRealloc(0);
}
/**
* Pushes or pops from the back to resize. Pushes will be default
* initialized.
*/
void resize_back(int newCount) {
SkASSERT(newCount >= 0);
if (newCount > fCount) {
push_back_n(newCount - fCount);
} else if (newCount < fCount) {
pop_back_n(fCount - newCount);
}
}
/**
* Get the i^th element.
*/
T& operator[] (int i) {
SkASSERT(i < fCount);
SkASSERT(i >= 0);
return fItemArray[i];
}
const T& operator[] (int i) const {
SkASSERT(i < fCount);
SkASSERT(i >= 0);
return fItemArray[i];
}
/**
* equivalent to operator[](0)
*/
T& front() { SkASSERT(fCount > 0); return fItemArray[0];}
const T& front() const { SkASSERT(fCount > 0); return fItemArray[0];}
/**
* equivalent to operator[](count() - 1)
*/
T& back() { SkASSERT(fCount); return fItemArray[fCount - 1];}
const T& back() const { SkASSERT(fCount > 0); return fItemArray[fCount - 1];}
/**
* equivalent to operator[](count()-1-i)
*/
T& fromBack(int i) {
SkASSERT(i >= 0);
SkASSERT(i < fCount);
return fItemArray[fCount - i - 1];
}
const T& fromBack(int i) const {
SkASSERT(i >= 0);
SkASSERT(i < fCount);
return fItemArray[fCount - i - 1];
}
protected:
/**
* Creates an empty array that will use the passed storage block until it
* is insufficiently large to hold the entire array.
*/
template <int N>
SkTArray(SkAlignedSTStorage<N,T>* storage) {
this->init(NULL, 0, storage->get(), N);
}
/**
* Copy another array, using preallocated storage if preAllocCount >=
* array.count(). Otherwise storage will only be used when array shrinks
* to fit.
*/
template <int N>
SkTArray(const SkTArray& array, SkAlignedSTStorage<N,T>* storage) {
this->init(array.fItemArray, array.fCount, storage->get(), N);
}
/**
* Copy a C array, using preallocated storage if preAllocCount >=
* count. Otherwise storage will only be used when array shrinks
* to fit.
*/
template <int N>
SkTArray(const T* array, int count, SkAlignedSTStorage<N,T>* storage) {
this->init(array, count, storage->get(), N);
}
void init(const T* array, int count,
void* preAllocStorage, int preAllocOrReserveCount) {
SkASSERT(count >= 0);
SkASSERT(preAllocOrReserveCount >= 0);
fCount = count;
fReserveCount = (preAllocOrReserveCount > 0) ?
preAllocOrReserveCount :
gMIN_ALLOC_COUNT;
fPreAllocMemArray = preAllocStorage;
if (fReserveCount >= fCount &&
NULL != preAllocStorage) {
fAllocCount = fReserveCount;
fMemArray = preAllocStorage;
} else {
fAllocCount = SkMax32(fCount, fReserveCount);
fMemArray = sk_malloc_throw(fAllocCount * sizeof(T));
}
SkTArrayExt::copy(this, array);
}
private:
static const int gMIN_ALLOC_COUNT = 8;
inline void checkRealloc(int delta) {
SkASSERT(fCount >= 0);
SkASSERT(fAllocCount >= 0);
SkASSERT(-delta <= fCount);
int newCount = fCount + delta;
int newAllocCount = fAllocCount;
if (newCount > fAllocCount || newCount < (fAllocCount / 3)) {
// whether we're growing or shrinking, we leave at least 50% extra space for future
// growth (clamped to the reserve count).
newAllocCount = SkMax32(newCount + ((newCount + 1) >> 1), fReserveCount);
}
if (newAllocCount != fAllocCount) {
fAllocCount = newAllocCount;
char* newMemArray;
if (fAllocCount == fReserveCount && NULL != fPreAllocMemArray) {
newMemArray = (char*) fPreAllocMemArray;
} else {
newMemArray = (char*) sk_malloc_throw(fAllocCount*sizeof(T));
}
SkTArrayExt::copyAndDelete<T>(this, newMemArray);
if (fMemArray != fPreAllocMemArray) {
sk_free(fMemArray);
}
fMemArray = newMemArray;
}
}
template<typename X> friend void SkTArrayExt::copy(SkTArray<X, true>* that, const X*);
template<typename X> friend void SkTArrayExt::copyAndDelete(SkTArray<X, true>* that, char*);
template<typename X> friend void SkTArrayExt::copy(SkTArray<X, false>* that, const X*);
template<typename X> friend void SkTArrayExt::copyAndDelete(SkTArray<X, false>* that, char*);
int fReserveCount;
int fCount;
int fAllocCount;
void* fPreAllocMemArray;
union {
T* fItemArray;
void* fMemArray;
};
};
/**
* Subclass of SkTArray that contains a preallocated memory block for the array.
*/
template <int N, typename T, bool DATA_TYPE = false>
class SkSTArray : public SkTArray<T, DATA_TYPE> {
private:
typedef SkTArray<T, DATA_TYPE> INHERITED;
public:
SkSTArray() : INHERITED(&fStorage) {
}
SkSTArray(const SkSTArray& array)
: INHERITED(array, &fStorage) {
}
explicit SkSTArray(const INHERITED& array)
: INHERITED(array, &fStorage) {
}
SkSTArray(const T* array, int count)
: INHERITED(array, count, &fStorage) {
}
SkSTArray& operator= (const SkSTArray& array) {
return *this = *(const INHERITED*)&array;
}
SkSTArray& operator= (const INHERITED& array) {
INHERITED::operator=(array);
return *this;
}
private:
SkAlignedSTStorage<N,T> fStorage;
};
#endif