1/*
2 * Copyright 2011 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef SkTArray_DEFINED
9#define SkTArray_DEFINED
10
11#include <new>
12#include "SkTypes.h"
13#include "SkTemplates.h"
14
15template <typename T, bool MEM_COPY = false> class SkTArray;
16
17namespace SkTArrayExt {
18
19template<typename T>
20inline void copy(SkTArray<T, true>* self, int dst, int src) {
21    memcpy(&self->fItemArray[dst], &self->fItemArray[src], sizeof(T));
22}
23template<typename T>
24inline void copy(SkTArray<T, true>* self, const T* array) {
25    memcpy(self->fMemArray, array, self->fCount * sizeof(T));
26}
27template<typename T>
28inline void copyAndDelete(SkTArray<T, true>* self, char* newMemArray) {
29    memcpy(newMemArray, self->fMemArray, self->fCount * sizeof(T));
30}
31
32template<typename T>
33inline void copy(SkTArray<T, false>* self, int dst, int src) {
34    SkNEW_PLACEMENT_ARGS(&self->fItemArray[dst], T, (self->fItemArray[src]));
35}
36template<typename T>
37inline void copy(SkTArray<T, false>* self, const T* array) {
38    for (int i = 0; i < self->fCount; ++i) {
39        SkNEW_PLACEMENT_ARGS(self->fItemArray + i, T, (array[i]));
40    }
41}
42template<typename T>
43inline void copyAndDelete(SkTArray<T, false>* self, char* newMemArray) {
44    for (int i = 0; i < self->fCount; ++i) {
45        SkNEW_PLACEMENT_ARGS(newMemArray + sizeof(T) * i, T, (self->fItemArray[i]));
46        self->fItemArray[i].~T();
47    }
48}
49
50}
51
52template <typename T, bool MEM_COPY> void* operator new(size_t, SkTArray<T, MEM_COPY>*, int);
53
54/** When MEM_COPY is true T will be bit copied when moved.
55    When MEM_COPY is false, T will be copy constructed / destructed.
56    In all cases T will be default-initialized on allocation,
57    and its destructor will be called from this object's destructor.
58*/
59template <typename T, bool MEM_COPY> class SkTArray {
60public:
61    /**
62     * Creates an empty array with no initial storage
63     */
64    SkTArray() {
65        fCount = 0;
66        fReserveCount = gMIN_ALLOC_COUNT;
67        fAllocCount = 0;
68        fMemArray = NULL;
69        fPreAllocMemArray = NULL;
70    }
71
72    /**
73     * Creates an empty array that will preallocate space for reserveCount
74     * elements.
75     */
76    explicit SkTArray(int reserveCount) {
77        this->init(NULL, 0, NULL, reserveCount);
78    }
79
80    /**
81     * Copies one array to another. The new array will be heap allocated.
82     */
83    explicit SkTArray(const SkTArray& array) {
84        this->init(array.fItemArray, array.fCount, NULL, 0);
85    }
86
87    /**
88     * Creates a SkTArray by copying contents of a standard C array. The new
89     * array will be heap allocated. Be careful not to use this constructor
90     * when you really want the (void*, int) version.
91     */
92    SkTArray(const T* array, int count) {
93        this->init(array, count, NULL, 0);
94    }
95
96    /**
97     * assign copy of array to this
98     */
99    SkTArray& operator =(const SkTArray& array) {
100        for (int i = 0; i < fCount; ++i) {
101            fItemArray[i].~T();
102        }
103        fCount = 0;
104        this->checkRealloc((int)array.count());
105        fCount = array.count();
106        SkTArrayExt::copy(this, static_cast<const T*>(array.fMemArray));
107        return *this;
108    }
109
110    virtual ~SkTArray() {
111        for (int i = 0; i < fCount; ++i) {
112            fItemArray[i].~T();
113        }
114        if (fMemArray != fPreAllocMemArray) {
115            sk_free(fMemArray);
116        }
117    }
118
119    /**
120     * Resets to count() == 0
121     */
122    void reset() { this->pop_back_n(fCount); }
123
124    /**
125     * Resets to count() = n newly constructed T objects.
126     */
127    void reset(int n) {
128        SkASSERT(n >= 0);
129        for (int i = 0; i < fCount; ++i) {
130            fItemArray[i].~T();
131        }
132        // set fCount to 0 before calling checkRealloc so that no copy cons. are called.
133        fCount = 0;
134        this->checkRealloc(n);
135        fCount = n;
136        for (int i = 0; i < fCount; ++i) {
137            SkNEW_PLACEMENT(fItemArray + i, T);
138        }
139    }
140
141    /**
142     * Resets to a copy of a C array.
143     */
144    void reset(const T* array, int count) {
145        for (int i = 0; i < fCount; ++i) {
146            fItemArray[i].~T();
147        }
148        int delta = count - fCount;
149        this->checkRealloc(delta);
150        fCount = count;
151        SkTArrayExt::copy(this, array);
152    }
153
154    void removeShuffle(int n) {
155        SkASSERT(n < fCount);
156        int newCount = fCount - 1;
157        fCount = newCount;
158        fItemArray[n].~T();
159        if (n != newCount) {
160            SkTArrayExt::copy(this, n, newCount);
161            fItemArray[newCount].~T();
162        }
163    }
164
165    /**
166     * Number of elements in the array.
167     */
168    int count() const { return fCount; }
169
170    /**
171     * Is the array empty.
172     */
173    bool empty() const { return !fCount; }
174
175    /**
176     * Adds 1 new default-initialized T value and returns it by reference. Note
177     * the reference only remains valid until the next call that adds or removes
178     * elements.
179     */
180    T& push_back() {
181        T* newT = reinterpret_cast<T*>(this->push_back_raw(1));
182        SkNEW_PLACEMENT(newT, T);
183        return *newT;
184    }
185
186    /**
187     * Version of above that uses a copy constructor to initialize the new item
188     */
189    T& push_back(const T& t) {
190        T* newT = reinterpret_cast<T*>(this->push_back_raw(1));
191        SkNEW_PLACEMENT_ARGS(newT, T, (t));
192        return *newT;
193    }
194
195    /**
196     * Allocates n more default-initialized T values, and returns the address of
197     * the start of that new range. Note: this address is only valid until the
198     * next API call made on the array that might add or remove elements.
199     */
200    T* push_back_n(int n) {
201        SkASSERT(n >= 0);
202        T* newTs = reinterpret_cast<T*>(this->push_back_raw(n));
203        for (int i = 0; i < n; ++i) {
204            SkNEW_PLACEMENT(newTs + i, T);
205        }
206        return newTs;
207    }
208
209    /**
210     * Version of above that uses a copy constructor to initialize all n items
211     * to the same T.
212     */
213    T* push_back_n(int n, const T& t) {
214        SkASSERT(n >= 0);
215        T* newTs = reinterpret_cast<T*>(this->push_back_raw(n));
216        for (int i = 0; i < n; ++i) {
217            SkNEW_PLACEMENT_ARGS(newTs[i], T, (t));
218        }
219        return newTs;
220    }
221
222    /**
223     * Version of above that uses a copy constructor to initialize the n items
224     * to separate T values.
225     */
226    T* push_back_n(int n, const T t[]) {
227        SkASSERT(n >= 0);
228        this->checkRealloc(n);
229        for (int i = 0; i < n; ++i) {
230            SkNEW_PLACEMENT_ARGS(fItemArray + fCount + i, T, (t[i]));
231        }
232        fCount += n;
233        return fItemArray + fCount - n;
234    }
235
236    /**
237     * Removes the last element. Not safe to call when count() == 0.
238     */
239    void pop_back() {
240        SkASSERT(fCount > 0);
241        --fCount;
242        fItemArray[fCount].~T();
243        this->checkRealloc(0);
244    }
245
246    /**
247     * Removes the last n elements. Not safe to call when count() < n.
248     */
249    void pop_back_n(int n) {
250        SkASSERT(n >= 0);
251        SkASSERT(fCount >= n);
252        fCount -= n;
253        for (int i = 0; i < n; ++i) {
254            fItemArray[fCount + i].~T();
255        }
256        this->checkRealloc(0);
257    }
258
259    /**
260     * Pushes or pops from the back to resize. Pushes will be default
261     * initialized.
262     */
263    void resize_back(int newCount) {
264        SkASSERT(newCount >= 0);
265
266        if (newCount > fCount) {
267            this->push_back_n(newCount - fCount);
268        } else if (newCount < fCount) {
269            this->pop_back_n(fCount - newCount);
270        }
271    }
272
273    T* begin() {
274        return fItemArray;
275    }
276    const T* begin() const {
277        return fItemArray;
278    }
279    T* end() {
280        return fItemArray ? fItemArray + fCount : NULL;
281    }
282    const T* end() const {
283        return fItemArray ? fItemArray + fCount : NULL;;
284    }
285
286   /**
287     * Get the i^th element.
288     */
289    T& operator[] (int i) {
290        SkASSERT(i < fCount);
291        SkASSERT(i >= 0);
292        return fItemArray[i];
293    }
294
295    const T& operator[] (int i) const {
296        SkASSERT(i < fCount);
297        SkASSERT(i >= 0);
298        return fItemArray[i];
299    }
300
301    /**
302     * equivalent to operator[](0)
303     */
304    T& front() { SkASSERT(fCount > 0); return fItemArray[0];}
305
306    const T& front() const { SkASSERT(fCount > 0); return fItemArray[0];}
307
308    /**
309     * equivalent to operator[](count() - 1)
310     */
311    T& back() { SkASSERT(fCount); return fItemArray[fCount - 1];}
312
313    const T& back() const { SkASSERT(fCount > 0); return fItemArray[fCount - 1];}
314
315    /**
316     * equivalent to operator[](count()-1-i)
317     */
318    T& fromBack(int i) {
319        SkASSERT(i >= 0);
320        SkASSERT(i < fCount);
321        return fItemArray[fCount - i - 1];
322    }
323
324    const T& fromBack(int i) const {
325        SkASSERT(i >= 0);
326        SkASSERT(i < fCount);
327        return fItemArray[fCount - i - 1];
328    }
329
330    bool operator==(const SkTArray<T, MEM_COPY>& right) const {
331        int leftCount = this->count();
332        if (leftCount != right.count()) {
333            return false;
334        }
335        for (int index = 0; index < leftCount; ++index) {
336            if (fItemArray[index] != right.fItemArray[index]) {
337                return false;
338            }
339        }
340        return true;
341    }
342
343    bool operator!=(const SkTArray<T, MEM_COPY>& right) const {
344        return !(*this == right);
345    }
346
347protected:
348    /**
349     * Creates an empty array that will use the passed storage block until it
350     * is insufficiently large to hold the entire array.
351     */
352    template <int N>
353    SkTArray(SkAlignedSTStorage<N,T>* storage) {
354        this->init(NULL, 0, storage->get(), N);
355    }
356
357    /**
358     * Copy another array, using preallocated storage if preAllocCount >=
359     * array.count(). Otherwise storage will only be used when array shrinks
360     * to fit.
361     */
362    template <int N>
363    SkTArray(const SkTArray& array, SkAlignedSTStorage<N,T>* storage) {
364        this->init(array.fItemArray, array.fCount, storage->get(), N);
365    }
366
367    /**
368     * Copy a C array, using preallocated storage if preAllocCount >=
369     * count. Otherwise storage will only be used when array shrinks
370     * to fit.
371     */
372    template <int N>
373    SkTArray(const T* array, int count, SkAlignedSTStorage<N,T>* storage) {
374        this->init(array, count, storage->get(), N);
375    }
376
377    void init(const T* array, int count,
378               void* preAllocStorage, int preAllocOrReserveCount) {
379        SkASSERT(count >= 0);
380        SkASSERT(preAllocOrReserveCount >= 0);
381        fCount              = count;
382        fReserveCount       = (preAllocOrReserveCount > 0) ?
383                                    preAllocOrReserveCount :
384                                    gMIN_ALLOC_COUNT;
385        fPreAllocMemArray   = preAllocStorage;
386        if (fReserveCount >= fCount &&
387            preAllocStorage) {
388            fAllocCount = fReserveCount;
389            fMemArray = preAllocStorage;
390        } else {
391            fAllocCount = SkMax32(fCount, fReserveCount);
392            fMemArray = sk_malloc_throw(fAllocCount * sizeof(T));
393        }
394
395        SkTArrayExt::copy(this, array);
396    }
397
398private:
399
400    static const int gMIN_ALLOC_COUNT = 8;
401
402    // Helper function that makes space for n objects, adjusts the count, but does not initialize
403    // the new objects.
404    void* push_back_raw(int n) {
405        this->checkRealloc(n);
406        void* ptr = fItemArray + fCount;
407        fCount += n;
408        return ptr;
409    }
410
411    inline void checkRealloc(int delta) {
412        SkASSERT(fCount >= 0);
413        SkASSERT(fAllocCount >= 0);
414
415        SkASSERT(-delta <= fCount);
416
417        int newCount = fCount + delta;
418        int newAllocCount = fAllocCount;
419
420        if (newCount > fAllocCount || newCount < (fAllocCount / 3)) {
421            // whether we're growing or shrinking, we leave at least 50% extra space for future
422            // growth (clamped to the reserve count).
423            newAllocCount = SkMax32(newCount + ((newCount + 1) >> 1), fReserveCount);
424        }
425        if (newAllocCount != fAllocCount) {
426
427            fAllocCount = newAllocCount;
428            char* newMemArray;
429
430            if (fAllocCount == fReserveCount && fPreAllocMemArray) {
431                newMemArray = (char*) fPreAllocMemArray;
432            } else {
433                newMemArray = (char*) sk_malloc_throw(fAllocCount*sizeof(T));
434            }
435
436            SkTArrayExt::copyAndDelete<T>(this, newMemArray);
437
438            if (fMemArray != fPreAllocMemArray) {
439                sk_free(fMemArray);
440            }
441            fMemArray = newMemArray;
442        }
443    }
444
445    friend void* operator new<T>(size_t, SkTArray*, int);
446
447    template<typename X> friend void SkTArrayExt::copy(SkTArray<X, true>* that, int dst, int src);
448    template<typename X> friend void SkTArrayExt::copy(SkTArray<X, true>* that, const X*);
449    template<typename X> friend void SkTArrayExt::copyAndDelete(SkTArray<X, true>* that, char*);
450
451    template<typename X> friend void SkTArrayExt::copy(SkTArray<X, false>* that, int dst, int src);
452    template<typename X> friend void SkTArrayExt::copy(SkTArray<X, false>* that, const X*);
453    template<typename X> friend void SkTArrayExt::copyAndDelete(SkTArray<X, false>* that, char*);
454
455    int fReserveCount;
456    int fCount;
457    int fAllocCount;
458    void*    fPreAllocMemArray;
459    union {
460        T*       fItemArray;
461        void*    fMemArray;
462    };
463};
464
465// Use the below macro (SkNEW_APPEND_TO_TARRAY) rather than calling this directly
466template <typename T, bool MEM_COPY>
467void* operator new(size_t, SkTArray<T, MEM_COPY>* array, int atIndex) {
468    // Currently, we only support adding to the end of the array. When the array class itself
469    // supports random insertion then this should be updated.
470    // SkASSERT(atIndex >= 0 && atIndex <= array->count());
471    SkASSERT(atIndex == array->count());
472    return array->push_back_raw(1);
473}
474
475// Skia doesn't use C++ exceptions but it may be compiled with them enabled. Having an op delete
476// to match the op new silences warnings about missing op delete when a constructor throws an
477// exception.
478template <typename T, bool MEM_COPY>
479void operator delete(void*, SkTArray<T, MEM_COPY>* array, int atIndex) {
480    SK_CRASH();
481}
482
483// Constructs a new object as the last element of an SkTArray.
484#define SkNEW_APPEND_TO_TARRAY(array_ptr, type_name, args)  \
485    (new ((array_ptr), (array_ptr)->count()) type_name args)
486
487
488/**
489 * Subclass of SkTArray that contains a preallocated memory block for the array.
490 */
491template <int N, typename T, bool MEM_COPY = false>
492class SkSTArray : public SkTArray<T, MEM_COPY> {
493private:
494    typedef SkTArray<T, MEM_COPY> INHERITED;
495
496public:
497    SkSTArray() : INHERITED(&fStorage) {
498    }
499
500    SkSTArray(const SkSTArray& array)
501        : INHERITED(array, &fStorage) {
502    }
503
504    explicit SkSTArray(const INHERITED& array)
505        : INHERITED(array, &fStorage) {
506    }
507
508    explicit SkSTArray(int reserveCount)
509        : INHERITED(reserveCount) {
510    }
511
512    SkSTArray(const T* array, int count)
513        : INHERITED(array, count, &fStorage) {
514    }
515
516    SkSTArray& operator= (const SkSTArray& array) {
517        return *this = *(const INHERITED*)&array;
518    }
519
520    SkSTArray& operator= (const INHERITED& array) {
521        INHERITED::operator=(array);
522        return *this;
523    }
524
525private:
526    SkAlignedSTStorage<N,T> fStorage;
527};
528
529#endif
530