/*
* 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 "../private/SkTLogic.h"
#include "../private/SkTemplates.h"
#include "SkTypes.h"
#include <new>
#include <utility>
/** 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 will be default-initialized on allocation,
and its destructor will be called from this object's destructor.
*/
template <typename T, bool MEM_COPY = false> 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;
this->checkRealloc((int)array.count());
fCount = array.count();
this->copy(static_cast<const T*>(array.fMemArray));
return *this;
}
~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); }
/**
* Resets to count() = n newly constructed T objects.
*/
void reset(int n) {
SkASSERT(n >= 0);
for (int i = 0; i < fCount; ++i) {
fItemArray[i].~T();
}
// set fCount to 0 before calling checkRealloc so that no copy cons. are called.
fCount = 0;
this->checkRealloc(n);
fCount = n;
for (int i = 0; i < fCount; ++i) {
new (fItemArray + i) T;
}
}
/**
* Resets to a copy of a C array.
*/
void reset(const T* array, int count) {
for (int i = 0; i < fCount; ++i) {
fItemArray[i].~T();
}
int delta = count - fCount;
this->checkRealloc(delta);
fCount = count;
this->copy(array);
}
void removeShuffle(int n) {
SkASSERT(n < fCount);
int newCount = fCount - 1;
fCount = newCount;
fItemArray[n].~T();
if (n != newCount) {
this->move(n, newCount);
}
}
/**
* Number of elements in the array.
*/
int count() const { return fCount; }
/**
* Is the array empty.
*/
bool empty() const { return !fCount; }
/**
* Adds 1 new default-initialized T value and returns it by reference. Note
* the reference only remains valid until the next call that adds or removes
* elements.
*/
T& push_back() {
T* newT = reinterpret_cast<T*>(this->push_back_raw(1));
new (newT) T;
return *newT;
}
/**
* Version of above that uses a copy constructor to initialize the new item
*/
T& push_back(const T& t) {
T* newT = reinterpret_cast<T*>(this->push_back_raw(1));
new (newT) T(t);
return *newT;
}
/**
* Construct a new T at the back of this array.
*/
template<class... Args> T& emplace_back(Args&&... args) {
T* newT = reinterpret_cast<T*>(this->push_back_raw(1));
return *new (newT) T(std::forward<Args>(args)...);
}
/**
* Allocates n more default-initialized 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);
T* newTs = reinterpret_cast<T*>(this->push_back_raw(n));
for (int i = 0; i < n; ++i) {
new (newTs + i) T;
}
return newTs;
}
/**
* 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);
T* newTs = reinterpret_cast<T*>(this->push_back_raw(n));
for (int i = 0; i < n; ++i) {
new (newTs[i]) T(t);
}
return newTs;
}
/**
* 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);
this->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();
this->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[fCount + i].~T();
}
this->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) {
this->push_back_n(newCount - fCount);
} else if (newCount < fCount) {
this->pop_back_n(fCount - newCount);
}
}
/** Swaps the contents of this array with that array. Does a pointer swap if possible,
otherwise copies the T values. */
void swap(SkTArray* that) {
if (this == that) {
return;
}
if (this->fPreAllocMemArray != this->fItemArray &&
that->fPreAllocMemArray != that->fItemArray) {
// If neither is using a preallocated array then just swap.
SkTSwap(fItemArray, that->fItemArray);
SkTSwap(fCount, that->fCount);
SkTSwap(fAllocCount, that->fAllocCount);
} else {
// This could be more optimal...
SkTArray copy(*that);
*that = *this;
*this = copy;
}
}
T* begin() {
return fItemArray;
}
const T* begin() const {
return fItemArray;
}
T* end() {
return fItemArray ? fItemArray + fCount : NULL;
}
const T* end() const {
return fItemArray ? fItemArray + fCount : NULL;
}
/**
* 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];
}
bool operator==(const SkTArray<T, MEM_COPY>& right) const {
int leftCount = this->count();
if (leftCount != right.count()) {
return false;
}
for (int index = 0; index < leftCount; ++index) {
if (fItemArray[index] != right.fItemArray[index]) {
return false;
}
}
return true;
}
bool operator!=(const SkTArray<T, MEM_COPY>& right) const {
return !(*this == right);
}
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 &&
preAllocStorage) {
fAllocCount = fReserveCount;
fMemArray = preAllocStorage;
} else {
fAllocCount = SkMax32(fCount, fReserveCount);
fMemArray = sk_malloc_throw(fAllocCount * sizeof(T));
}
this->copy(array);
}
private:
/** In the following move and copy methods, 'dst' is assumed to be uninitialized raw storage.
* In the following move methods, 'src' is destroyed leaving behind uninitialized raw storage.
*/
template <bool E = MEM_COPY> SK_WHEN(E, void) copy(const T* src) {
sk_careful_memcpy(fMemArray, src, fCount * sizeof(T));
}
template <bool E = MEM_COPY> SK_WHEN(E, void) move(int dst, int src) {
memcpy(&fItemArray[dst], &fItemArray[src], sizeof(T));
}
template <bool E = MEM_COPY> SK_WHEN(E, void) move(char* dst) {
sk_careful_memcpy(dst, fMemArray, fCount * sizeof(T));
}
template <bool E = MEM_COPY> SK_WHEN(!E, void) copy(const T* src) {
for (int i = 0; i < fCount; ++i) {
new (fItemArray + i) T(src[i]);
}
}
template <bool E = MEM_COPY> SK_WHEN(!E, void) move(int dst, int src) {
new (&fItemArray[dst]) T(std::move(fItemArray[src]));
fItemArray[src].~T();
}
template <bool E = MEM_COPY> SK_WHEN(!E, void) move(char* dst) {
for (int i = 0; i < fCount; ++i) {
new (dst + sizeof(T) * i) T(std::move(fItemArray[i]));
fItemArray[i].~T();
}
}
static const int gMIN_ALLOC_COUNT = 8;
// Helper function that makes space for n objects, adjusts the count, but does not initialize
// the new objects.
void* push_back_raw(int n) {
this->checkRealloc(n);
void* ptr = fItemArray + fCount;
fCount += n;
return ptr;
}
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 && fPreAllocMemArray) {
newMemArray = (char*) fPreAllocMemArray;
} else {
newMemArray = (char*) sk_malloc_throw(fAllocCount*sizeof(T));
}
this->move(newMemArray);
if (fMemArray != fPreAllocMemArray) {
sk_free(fMemArray);
}
fMemArray = newMemArray;
}
}
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 MEM_COPY = false>
class SkSTArray : public SkTArray<T, MEM_COPY> {
private:
typedef SkTArray<T, MEM_COPY> INHERITED;
public:
SkSTArray() : INHERITED(&fStorage) {
}
SkSTArray(const SkSTArray& array)
: INHERITED(array, &fStorage) {
}
explicit SkSTArray(const INHERITED& array)
: INHERITED(array, &fStorage) {
}
explicit SkSTArray(int reserveCount)
: INHERITED(reserveCount) {
}
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