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+/*
+ * Copyright 2006 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkTemplates_DEFINED
+#define SkTemplates_DEFINED
+
+#include "include/core/SkTypes.h"
+#include "include/private/SkMalloc.h"
+#include "include/private/SkTLogic.h"
+
+#include <string.h>
+#include <array>
+#include <cstddef>
+#include <memory>
+#include <new>
+#include <utility>
+
+/** \file SkTemplates.h
+
+ This file contains light-weight template classes for type-safe and exception-safe
+ resource management.
+*/
+
+/**
+ * Marks a local variable as known to be unused (to avoid warnings).
+ * Note that this does *not* prevent the local variable from being optimized away.
+ */
+template<typename T> inline void sk_ignore_unused_variable(const T&) { }
+
+/**
+ * Returns a pointer to a D which comes immediately after S[count].
+ */
+template <typename D, typename S> static D* SkTAfter(S* ptr, size_t count = 1) {
+ return reinterpret_cast<D*>(ptr + count);
+}
+
+/**
+ * Returns a pointer to a D which comes byteOffset bytes after S.
+ */
+template <typename D, typename S> static D* SkTAddOffset(S* ptr, size_t byteOffset) {
+ // The intermediate char* has the same cv-ness as D as this produces better error messages.
+ // This relies on the fact that reinterpret_cast can add constness, but cannot remove it.
+ return reinterpret_cast<D*>(reinterpret_cast<sknonstd::same_cv_t<char, D>*>(ptr) + byteOffset);
+}
+
+// TODO: when C++17 the language is available, use template <auto P>
+template <typename T, T* P> struct SkFunctionWrapper {
+ template <typename... Args>
+ auto operator()(Args&&... args) const -> decltype(P(std::forward<Args>(args)...)) {
+ return P(std::forward<Args>(args)...);
+ }
+};
+
+/** \class SkAutoTCallVProc
+
+ Call a function when this goes out of scope. The template uses two
+ parameters, the object, and a function that is to be called in the destructor.
+ If release() is called, the object reference is set to null. If the object
+ reference is null when the destructor is called, we do not call the
+ function.
+*/
+template <typename T, void (*P)(T*)> class SkAutoTCallVProc
+ : public std::unique_ptr<T, SkFunctionWrapper<skstd::remove_pointer_t<decltype(P)>, P>> {
+public:
+ SkAutoTCallVProc(T* obj)
+ : std::unique_ptr<T, SkFunctionWrapper<skstd::remove_pointer_t<decltype(P)>, P>>(obj) {}
+
+ operator T*() const { return this->get(); }
+};
+
+/** Allocate an array of T elements, and free the array in the destructor
+ */
+template <typename T> class SkAutoTArray {
+public:
+ SkAutoTArray() {}
+ /** Allocate count number of T elements
+ */
+ explicit SkAutoTArray(int count) {
+ SkASSERT(count >= 0);
+ if (count) {
+ fArray.reset(new T[count]);
+ }
+ SkDEBUGCODE(fCount = count;)
+ }
+
+ SkAutoTArray(SkAutoTArray&& other) : fArray(std::move(other.fArray)) {
+ SkDEBUGCODE(fCount = other.fCount; other.fCount = 0;)
+ }
+ SkAutoTArray& operator=(SkAutoTArray&& other) {
+ if (this != &other) {
+ fArray = std::move(other.fArray);
+ SkDEBUGCODE(fCount = other.fCount; other.fCount = 0;)
+ }
+ return *this;
+ }
+
+ /** Reallocates given a new count. Reallocation occurs even if new count equals old count.
+ */
+ void reset(int count) { *this = SkAutoTArray(count); }
+
+ /** Return the array of T elements. Will be NULL if count == 0
+ */
+ T* get() const { return fArray.get(); }
+
+ /** Return the nth element in the array
+ */
+ T& operator[](int index) const {
+ SkASSERT((unsigned)index < (unsigned)fCount);
+ return fArray[index];
+ }
+
+private:
+ std::unique_ptr<T[]> fArray;
+ SkDEBUGCODE(int fCount = 0;)
+};
+
+/** Wraps SkAutoTArray, with room for kCountRequested elements preallocated.
+ */
+template <int kCountRequested, typename T> class SkAutoSTArray {
+public:
+ SkAutoSTArray(SkAutoSTArray&&) = delete;
+ SkAutoSTArray(const SkAutoSTArray&) = delete;
+ SkAutoSTArray& operator=(SkAutoSTArray&&) = delete;
+ SkAutoSTArray& operator=(const SkAutoSTArray&) = delete;
+
+ /** Initialize with no objects */
+ SkAutoSTArray() {
+ fArray = nullptr;
+ fCount = 0;
+ }
+
+ /** Allocate count number of T elements
+ */
+ SkAutoSTArray(int count) {
+ fArray = nullptr;
+ fCount = 0;
+ this->reset(count);
+ }
+
+ ~SkAutoSTArray() {
+ this->reset(0);
+ }
+
+ /** Destroys previous objects in the array and default constructs count number of objects */
+ void reset(int count) {
+ T* start = fArray;
+ T* iter = start + fCount;
+ while (iter > start) {
+ (--iter)->~T();
+ }
+
+ SkASSERT(count >= 0);
+ if (fCount != count) {
+ if (fCount > kCount) {
+ // 'fArray' was allocated last time so free it now
+ SkASSERT((T*) fStorage != fArray);
+ sk_free(fArray);
+ }
+
+ if (count > kCount) {
+ fArray = (T*) sk_malloc_throw(count, sizeof(T));
+ } else if (count > 0) {
+ fArray = (T*) fStorage;
+ } else {
+ fArray = nullptr;
+ }
+
+ fCount = count;
+ }
+
+ iter = fArray;
+ T* stop = fArray + count;
+ while (iter < stop) {
+ new (iter++) T;
+ }
+ }
+
+ /** Return the number of T elements in the array
+ */
+ int count() const { return fCount; }
+
+ /** Return the array of T elements. Will be NULL if count == 0
+ */
+ T* get() const { return fArray; }
+
+ T* begin() { return fArray; }
+
+ const T* begin() const { return fArray; }
+
+ T* end() { return fArray + fCount; }
+
+ const T* end() const { return fArray + fCount; }
+
+ /** Return the nth element in the array
+ */
+ T& operator[](int index) const {
+ SkASSERT(index < fCount);
+ return fArray[index];
+ }
+
+private:
+#if defined(SK_BUILD_FOR_GOOGLE3)
+ // Stack frame size is limited for SK_BUILD_FOR_GOOGLE3. 4k is less than the actual max, but some functions
+ // have multiple large stack allocations.
+ static const int kMaxBytes = 4 * 1024;
+ static const int kCount = kCountRequested * sizeof(T) > kMaxBytes
+ ? kMaxBytes / sizeof(T)
+ : kCountRequested;
+#else
+ static const int kCount = kCountRequested;
+#endif
+
+ int fCount;
+ T* fArray;
+ // since we come right after fArray, fStorage should be properly aligned
+ char fStorage[kCount * sizeof(T)];
+};
+
+/** Manages an array of T elements, freeing the array in the destructor.
+ * Does NOT call any constructors/destructors on T (T must be POD).
+ */
+template <typename T> class SkAutoTMalloc {
+public:
+ /** Takes ownership of the ptr. The ptr must be a value which can be passed to sk_free. */
+ explicit SkAutoTMalloc(T* ptr = nullptr) : fPtr(ptr) {}
+
+ /** Allocates space for 'count' Ts. */
+ explicit SkAutoTMalloc(size_t count)
+ : fPtr(count ? (T*)sk_malloc_throw(count, sizeof(T)) : nullptr) {}
+
+ SkAutoTMalloc(SkAutoTMalloc&&) = default;
+ SkAutoTMalloc& operator=(SkAutoTMalloc&&) = default;
+
+ /** Resize the memory area pointed to by the current ptr preserving contents. */
+ void realloc(size_t count) {
+ fPtr.reset(count ? (T*)sk_realloc_throw(fPtr.release(), count * sizeof(T)) : nullptr);
+ }
+
+ /** Resize the memory area pointed to by the current ptr without preserving contents. */
+ T* reset(size_t count = 0) {
+ fPtr.reset(count ? (T*)sk_malloc_throw(count, sizeof(T)) : nullptr);
+ return this->get();
+ }
+
+ T* get() const { return fPtr.get(); }
+
+ operator T*() { return fPtr.get(); }
+
+ operator const T*() const { return fPtr.get(); }
+
+ T& operator[](int index) { return fPtr.get()[index]; }
+
+ const T& operator[](int index) const { return fPtr.get()[index]; }
+
+ /**
+ * Transfer ownership of the ptr to the caller, setting the internal
+ * pointer to NULL. Note that this differs from get(), which also returns
+ * the pointer, but it does not transfer ownership.
+ */
+ T* release() { return fPtr.release(); }
+
+private:
+ std::unique_ptr<T, SkFunctionWrapper<void(void*), sk_free>> fPtr;
+};
+
+template <size_t kCountRequested, typename T> class SkAutoSTMalloc {
+public:
+ SkAutoSTMalloc() : fPtr(fTStorage) {}
+
+ SkAutoSTMalloc(size_t count) {
+ if (count > kCount) {
+ fPtr = (T*)sk_malloc_throw(count, sizeof(T));
+ } else if (count) {
+ fPtr = fTStorage;
+ } else {
+ fPtr = nullptr;
+ }
+ }
+
+ SkAutoSTMalloc(SkAutoSTMalloc&&) = delete;
+ SkAutoSTMalloc(const SkAutoSTMalloc&) = delete;
+ SkAutoSTMalloc& operator=(SkAutoSTMalloc&&) = delete;
+ SkAutoSTMalloc& operator=(const SkAutoSTMalloc&) = delete;
+
+ ~SkAutoSTMalloc() {
+ if (fPtr != fTStorage) {
+ sk_free(fPtr);
+ }
+ }
+
+ // doesn't preserve contents
+ T* reset(size_t count) {
+ if (fPtr != fTStorage) {
+ sk_free(fPtr);
+ }
+ if (count > kCount) {
+ fPtr = (T*)sk_malloc_throw(count, sizeof(T));
+ } else if (count) {
+ fPtr = fTStorage;
+ } else {
+ fPtr = nullptr;
+ }
+ return fPtr;
+ }
+
+ T* get() const { return fPtr; }
+
+ operator T*() {
+ return fPtr;
+ }
+
+ operator const T*() const {
+ return fPtr;
+ }
+
+ T& operator[](int index) {
+ return fPtr[index];
+ }
+
+ const T& operator[](int index) const {
+ return fPtr[index];
+ }
+
+ // Reallocs the array, can be used to shrink the allocation. Makes no attempt to be intelligent
+ void realloc(size_t count) {
+ if (count > kCount) {
+ if (fPtr == fTStorage) {
+ fPtr = (T*)sk_malloc_throw(count, sizeof(T));
+ memcpy(fPtr, fTStorage, kCount * sizeof(T));
+ } else {
+ fPtr = (T*)sk_realloc_throw(fPtr, count, sizeof(T));
+ }
+ } else if (count) {
+ if (fPtr != fTStorage) {
+ fPtr = (T*)sk_realloc_throw(fPtr, count, sizeof(T));
+ }
+ } else {
+ this->reset(0);
+ }
+ }
+
+private:
+ // Since we use uint32_t storage, we might be able to get more elements for free.
+ static const size_t kCountWithPadding = SkAlign4(kCountRequested*sizeof(T)) / sizeof(T);
+#if defined(SK_BUILD_FOR_GOOGLE3)
+ // Stack frame size is limited for SK_BUILD_FOR_GOOGLE3. 4k is less than the actual max, but some functions
+ // have multiple large stack allocations.
+ static const size_t kMaxBytes = 4 * 1024;
+ static const size_t kCount = kCountRequested * sizeof(T) > kMaxBytes
+ ? kMaxBytes / sizeof(T)
+ : kCountWithPadding;
+#else
+ static const size_t kCount = kCountWithPadding;
+#endif
+
+ T* fPtr;
+ union {
+ uint32_t fStorage32[SkAlign4(kCount*sizeof(T)) >> 2];
+ T fTStorage[1]; // do NOT want to invoke T::T()
+ };
+};
+
+//////////////////////////////////////////////////////////////////////////////////////////////////
+
+/**
+ * Pass the object and the storage that was offered during SkInPlaceNewCheck, and this will
+ * safely destroy (and free if it was dynamically allocated) the object.
+ */
+template <typename T> void SkInPlaceDeleteCheck(T* obj, void* storage) {
+ if (storage == obj) {
+ obj->~T();
+ } else {
+ delete obj;
+ }
+}
+
+/**
+ * Allocates T, using storage if it is large enough, and allocating on the heap (via new) if
+ * storage is not large enough.
+ *
+ * obj = SkInPlaceNewCheck<Type>(storage, size);
+ * ...
+ * SkInPlaceDeleteCheck(obj, storage);
+ */
+template<typename T, typename... Args>
+T* SkInPlaceNewCheck(void* storage, size_t size, Args&&... args) {
+ return (sizeof(T) <= size) ? new (storage) T(std::forward<Args>(args)...)
+ : new T(std::forward<Args>(args)...);
+}
+/**
+ * Reserves memory that is aligned on double and pointer boundaries.
+ * Hopefully this is sufficient for all practical purposes.
+ */
+template <size_t N> class SkAlignedSStorage {
+public:
+ SkAlignedSStorage() {}
+ SkAlignedSStorage(SkAlignedSStorage&&) = delete;
+ SkAlignedSStorage(const SkAlignedSStorage&) = delete;
+ SkAlignedSStorage& operator=(SkAlignedSStorage&&) = delete;
+ SkAlignedSStorage& operator=(const SkAlignedSStorage&) = delete;
+
+ size_t size() const { return N; }
+ void* get() { return fData; }
+ const void* get() const { return fData; }
+
+private:
+ union {
+ void* fPtr;
+ double fDouble;
+ char fData[N];
+ };
+};
+
+/**
+ * Reserves memory that is aligned on double and pointer boundaries.
+ * Hopefully this is sufficient for all practical purposes. Otherwise,
+ * we have to do some arcane trickery to determine alignment of non-POD
+ * types. Lifetime of the memory is the lifetime of the object.
+ */
+template <int N, typename T> class SkAlignedSTStorage {
+public:
+ SkAlignedSTStorage() {}
+ SkAlignedSTStorage(SkAlignedSTStorage&&) = delete;
+ SkAlignedSTStorage(const SkAlignedSTStorage&) = delete;
+ SkAlignedSTStorage& operator=(SkAlignedSTStorage&&) = delete;
+ SkAlignedSTStorage& operator=(const SkAlignedSTStorage&) = delete;
+
+ /**
+ * Returns void* because this object does not initialize the
+ * memory. Use placement new for types that require a cons.
+ */
+ void* get() { return fStorage.get(); }
+ const void* get() const { return fStorage.get(); }
+private:
+ SkAlignedSStorage<sizeof(T)*N> fStorage;
+};
+
+using SkAutoFree = std::unique_ptr<void, SkFunctionWrapper<void(void*), sk_free>>;
+
+template<typename C, std::size_t... Is>
+constexpr auto SkMakeArrayFromIndexSequence(C c, skstd::index_sequence<Is...>)
+-> std::array<skstd::result_of_t<C(std::size_t)>, sizeof...(Is)> {
+ return {{ c(Is)... }};
+}
+
+template<size_t N, typename C> constexpr auto SkMakeArray(C c)
+-> std::array<skstd::result_of_t<C(std::size_t)>, N> {
+ return SkMakeArrayFromIndexSequence(c, skstd::make_index_sequence<N>{});
+}
+
+#endif