skia2/include/core/SkTArray.h

550 lines
16 KiB
C++

/*
* 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, int dst, int src) {
memcpy(&self->fItemArray[dst], &self->fItemArray[src], sizeof(T));
}
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, int dst, int src) {
SkNEW_PLACEMENT_ARGS(&self->fItemArray[dst], T, (self->fItemArray[src]));
}
template<typename T>
inline void copy(SkTArray<T, false>* self, const T* array) {
for (int i = 0; i < self->fCount; ++i) {
SkNEW_PLACEMENT_ARGS(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) {
SkNEW_PLACEMENT_ARGS(newMemArray + sizeof(T) * i, T, (self->fItemArray[i]));
self->fItemArray[i].~T();
}
}
}
template <typename T, bool MEM_COPY> void* operator new(size_t, SkTArray<T, MEM_COPY>*, int);
/** 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> 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();
SkTArrayExt::copy(this, 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) {
SkNEW_PLACEMENT(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;
SkTArrayExt::copy(this, array);
}
void removeShuffle(int n) {
SkASSERT(n < fCount);
int newCount = fCount - 1;
fCount = newCount;
fItemArray[n].~T();
if (n != newCount) {
SkTArrayExt::copy(this, n, newCount);
fItemArray[newCount].~T();
}
}
/**
* 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));
SkNEW_PLACEMENT(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));
SkNEW_PLACEMENT_ARGS(newT, T, (t));
return *newT;
}
/**
* 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) {
SkNEW_PLACEMENT(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) {
SkNEW_PLACEMENT_ARGS(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) {
SkNEW_PLACEMENT_ARGS(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));
}
SkTArrayExt::copy(this, array);
}
private:
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));
}
SkTArrayExt::copyAndDelete<T>(this, newMemArray);
if (fMemArray != fPreAllocMemArray) {
sk_free(fMemArray);
}
fMemArray = newMemArray;
}
}
friend void* operator new<T>(size_t, SkTArray*, int);
template<typename X> friend void SkTArrayExt::copy(SkTArray<X, true>* that, int dst, int src);
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, int dst, int src);
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;
};
};
// Use the below macro (SkNEW_APPEND_TO_TARRAY) rather than calling this directly
template <typename T, bool MEM_COPY>
void* operator new(size_t, SkTArray<T, MEM_COPY>* array, int SkDEBUGCODE(atIndex)) {
// Currently, we only support adding to the end of the array. When the array class itself
// supports random insertion then this should be updated.
// SkASSERT(atIndex >= 0 && atIndex <= array->count());
SkASSERT(atIndex == array->count());
return array->push_back_raw(1);
}
// Skia doesn't use C++ exceptions but it may be compiled with them enabled. Having an op delete
// to match the op new silences warnings about missing op delete when a constructor throws an
// exception.
template <typename T, bool MEM_COPY>
void operator delete(void*, SkTArray<T, MEM_COPY>* /*array*/, int /*atIndex*/) {
SK_CRASH();
}
// Constructs a new object as the last element of an SkTArray.
#define SkNEW_APPEND_TO_TARRAY(array_ptr, type_name, args) \
(new ((array_ptr), (array_ptr)->count()) type_name args)
/**
* 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