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Diffstat (limited to 'intl/icu/source/common/cmemory.h')
| -rw-r--r-- | intl/icu/source/common/cmemory.h | 900 |
1 files changed, 900 insertions, 0 deletions
diff --git a/intl/icu/source/common/cmemory.h b/intl/icu/source/common/cmemory.h new file mode 100644 index 0000000000..3705c2dfd0 --- /dev/null +++ b/intl/icu/source/common/cmemory.h @@ -0,0 +1,900 @@ +// © 2016 and later: Unicode, Inc. and others. +// License & terms of use: http://www.unicode.org/copyright.html +/* +****************************************************************************** +* +* Copyright (C) 1997-2016, International Business Machines +* Corporation and others. All Rights Reserved. +* +****************************************************************************** +* +* File CMEMORY.H +* +* Contains stdlib.h/string.h memory functions +* +* @author Bertrand A. Damiba +* +* Modification History: +* +* Date Name Description +* 6/20/98 Bertrand Created. +* 05/03/99 stephen Changed from functions to macros. +* +****************************************************************************** +*/ + +#ifndef CMEMORY_H +#define CMEMORY_H + +#include "unicode/utypes.h" + +#include <stddef.h> +#include <string.h> +#include "unicode/localpointer.h" +#include "uassert.h" + +#if U_DEBUG && defined(UPRV_MALLOC_COUNT) +#include <stdio.h> +#endif + +// uprv_memcpy and uprv_memmove +#if defined(__clang__) +#define uprv_memcpy(dst, src, size) UPRV_BLOCK_MACRO_BEGIN { \ + /* Suppress warnings about addresses that will never be NULL */ \ + _Pragma("clang diagnostic push") \ + _Pragma("clang diagnostic ignored \"-Waddress\"") \ + U_ASSERT(dst != NULL); \ + U_ASSERT(src != NULL); \ + _Pragma("clang diagnostic pop") \ + U_STANDARD_CPP_NAMESPACE memcpy(dst, src, size); \ +} UPRV_BLOCK_MACRO_END +#define uprv_memmove(dst, src, size) UPRV_BLOCK_MACRO_BEGIN { \ + /* Suppress warnings about addresses that will never be NULL */ \ + _Pragma("clang diagnostic push") \ + _Pragma("clang diagnostic ignored \"-Waddress\"") \ + U_ASSERT(dst != NULL); \ + U_ASSERT(src != NULL); \ + _Pragma("clang diagnostic pop") \ + U_STANDARD_CPP_NAMESPACE memmove(dst, src, size); \ +} UPRV_BLOCK_MACRO_END +#elif defined(__GNUC__) +#define uprv_memcpy(dst, src, size) UPRV_BLOCK_MACRO_BEGIN { \ + /* Suppress warnings about addresses that will never be NULL */ \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Waddress\"") \ + U_ASSERT(dst != NULL); \ + U_ASSERT(src != NULL); \ + _Pragma("GCC diagnostic pop") \ + U_STANDARD_CPP_NAMESPACE memcpy(dst, src, size); \ +} UPRV_BLOCK_MACRO_END +#define uprv_memmove(dst, src, size) UPRV_BLOCK_MACRO_BEGIN { \ + /* Suppress warnings about addresses that will never be NULL */ \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Waddress\"") \ + U_ASSERT(dst != NULL); \ + U_ASSERT(src != NULL); \ + _Pragma("GCC diagnostic pop") \ + U_STANDARD_CPP_NAMESPACE memmove(dst, src, size); \ +} UPRV_BLOCK_MACRO_END +#else +#define uprv_memcpy(dst, src, size) UPRV_BLOCK_MACRO_BEGIN { \ + U_ASSERT(dst != NULL); \ + U_ASSERT(src != NULL); \ + U_STANDARD_CPP_NAMESPACE memcpy(dst, src, size); \ +} UPRV_BLOCK_MACRO_END +#define uprv_memmove(dst, src, size) UPRV_BLOCK_MACRO_BEGIN { \ + U_ASSERT(dst != NULL); \ + U_ASSERT(src != NULL); \ + U_STANDARD_CPP_NAMESPACE memmove(dst, src, size); \ +} UPRV_BLOCK_MACRO_END +#endif + +/** + * \def UPRV_LENGTHOF + * Convenience macro to determine the length of a fixed array at compile-time. + * @param array A fixed length array + * @return The length of the array, in elements + * @internal + */ +#define UPRV_LENGTHOF(array) (int32_t)(sizeof(array)/sizeof((array)[0])) +#define uprv_memset(buffer, mark, size) U_STANDARD_CPP_NAMESPACE memset(buffer, mark, size) +#define uprv_memcmp(buffer1, buffer2, size) U_STANDARD_CPP_NAMESPACE memcmp(buffer1, buffer2,size) +#define uprv_memchr(ptr, value, num) U_STANDARD_CPP_NAMESPACE memchr(ptr, value, num) + +U_CAPI void * U_EXPORT2 +uprv_malloc(size_t s) U_MALLOC_ATTR U_ALLOC_SIZE_ATTR(1); + +U_CAPI void * U_EXPORT2 +uprv_realloc(void *mem, size_t size) U_ALLOC_SIZE_ATTR(2); + +U_CAPI void U_EXPORT2 +uprv_free(void *mem); + +U_CAPI void * U_EXPORT2 +uprv_calloc(size_t num, size_t size) U_MALLOC_ATTR U_ALLOC_SIZE_ATTR2(1,2); + +/** + * Get the least significant bits of a pointer (a memory address). + * For example, with a mask of 3, the macro gets the 2 least significant bits, + * which will be 0 if the pointer is 32-bit (4-byte) aligned. + * + * uintptr_t is the most appropriate integer type to cast to. + */ +#define U_POINTER_MASK_LSB(ptr, mask) ((uintptr_t)(ptr) & (mask)) + +/** + * Create & return an instance of "type" in statically allocated storage. + * e.g. + * static std::mutex *myMutex = STATIC_NEW(std::mutex); + * To destroy an object created in this way, invoke the destructor explicitly, e.g. + * myMutex->~mutex(); + * DO NOT use delete. + * DO NOT use with class UMutex, which has specific support for static instances. + * + * STATIC_NEW is intended for use when + * - We want a static (or global) object. + * - We don't want it to ever be destructed, or to explicitly control destruction, + * to avoid use-after-destruction problems. + * - We want to avoid an ordinary heap allocated object, + * to avoid the possibility of memory allocation failures, and + * to avoid memory leak reports, from valgrind, for example. + * This is defined as a macro rather than a template function because each invocation + * must define distinct static storage for the object being returned. + */ +#define STATIC_NEW(type) [] () { \ + alignas(type) static char storage[sizeof(type)]; \ + return new(storage) type();} () + +/** + * Heap clean up function, called from u_cleanup() + * Clears any user heap functions from u_setMemoryFunctions() + * Does NOT deallocate any remaining allocated memory. + */ +U_CFUNC UBool +cmemory_cleanup(void); + +/** + * A function called by <TT>uhash_remove</TT>, + * <TT>uhash_close</TT>, or <TT>uhash_put</TT> to delete + * an existing key or value. + * @param obj A key or value stored in a hashtable + * @see uprv_deleteUObject + */ +typedef void U_CALLCONV UObjectDeleter(void* obj); + +/** + * Deleter for UObject instances. + * Works for all subclasses of UObject because it has a virtual destructor. + */ +U_CAPI void U_EXPORT2 +uprv_deleteUObject(void *obj); + +#ifdef __cplusplus + +#include <utility> +#include "unicode/uobject.h" + +U_NAMESPACE_BEGIN + +/** + * "Smart pointer" class, deletes memory via uprv_free(). + * For most methods see the LocalPointerBase base class. + * Adds operator[] for array item access. + * + * @see LocalPointerBase + */ +template<typename T> +class LocalMemory : public LocalPointerBase<T> { +public: + using LocalPointerBase<T>::operator*; + using LocalPointerBase<T>::operator->; + /** + * Constructor takes ownership. + * @param p simple pointer to an array of T items that is adopted + */ + explicit LocalMemory(T *p=nullptr) : LocalPointerBase<T>(p) {} + /** + * Move constructor, leaves src with isNull(). + * @param src source smart pointer + */ + LocalMemory(LocalMemory<T> &&src) noexcept : LocalPointerBase<T>(src.ptr) { + src.ptr=nullptr; + } + /** + * Destructor deletes the memory it owns. + */ + ~LocalMemory() { + uprv_free(LocalPointerBase<T>::ptr); + } + /** + * Move assignment operator, leaves src with isNull(). + * The behavior is undefined if *this and src are the same object. + * @param src source smart pointer + * @return *this + */ + LocalMemory<T> &operator=(LocalMemory<T> &&src) noexcept { + uprv_free(LocalPointerBase<T>::ptr); + LocalPointerBase<T>::ptr=src.ptr; + src.ptr=nullptr; + return *this; + } + /** + * Swap pointers. + * @param other other smart pointer + */ + void swap(LocalMemory<T> &other) noexcept { + T *temp=LocalPointerBase<T>::ptr; + LocalPointerBase<T>::ptr=other.ptr; + other.ptr=temp; + } + /** + * Non-member LocalMemory swap function. + * @param p1 will get p2's pointer + * @param p2 will get p1's pointer + */ + friend inline void swap(LocalMemory<T> &p1, LocalMemory<T> &p2) noexcept { + p1.swap(p2); + } + /** + * Deletes the array it owns, + * and adopts (takes ownership of) the one passed in. + * @param p simple pointer to an array of T items that is adopted + */ + void adoptInstead(T *p) { + uprv_free(LocalPointerBase<T>::ptr); + LocalPointerBase<T>::ptr=p; + } + /** + * Deletes the array it owns, allocates a new one and reset its bytes to 0. + * Returns the new array pointer. + * If the allocation fails, then the current array is unchanged and + * this method returns nullptr. + * @param newCapacity must be >0 + * @return the allocated array pointer, or nullptr if the allocation failed + */ + inline T *allocateInsteadAndReset(int32_t newCapacity=1); + /** + * Deletes the array it owns and allocates a new one, copying length T items. + * Returns the new array pointer. + * If the allocation fails, then the current array is unchanged and + * this method returns nullptr. + * @param newCapacity must be >0 + * @param length number of T items to be copied from the old array to the new one; + * must be no more than the capacity of the old array, + * which the caller must track because the LocalMemory does not track it + * @return the allocated array pointer, or nullptr if the allocation failed + */ + inline T *allocateInsteadAndCopy(int32_t newCapacity=1, int32_t length=0); + /** + * Array item access (writable). + * No index bounds check. + * @param i array index + * @return reference to the array item + */ + T &operator[](ptrdiff_t i) const { return LocalPointerBase<T>::ptr[i]; } +}; + +template<typename T> +inline T *LocalMemory<T>::allocateInsteadAndReset(int32_t newCapacity) { + if(newCapacity>0) { + T *p=(T *)uprv_malloc(newCapacity*sizeof(T)); + if(p!=nullptr) { + uprv_memset(p, 0, newCapacity*sizeof(T)); + uprv_free(LocalPointerBase<T>::ptr); + LocalPointerBase<T>::ptr=p; + } + return p; + } else { + return nullptr; + } +} + + +template<typename T> +inline T *LocalMemory<T>::allocateInsteadAndCopy(int32_t newCapacity, int32_t length) { + if(newCapacity>0) { + T *p=(T *)uprv_malloc(newCapacity*sizeof(T)); + if(p!=nullptr) { + if(length>0) { + if(length>newCapacity) { + length=newCapacity; + } + uprv_memcpy(p, LocalPointerBase<T>::ptr, (size_t)length*sizeof(T)); + } + uprv_free(LocalPointerBase<T>::ptr); + LocalPointerBase<T>::ptr=p; + } + return p; + } else { + return nullptr; + } +} + +/** + * Simple array/buffer management class using uprv_malloc() and uprv_free(). + * Provides an internal array with fixed capacity. Can alias another array + * or allocate one. + * + * The array address is properly aligned for type T. It might not be properly + * aligned for types larger than T (or larger than the largest subtype of T). + * + * Unlike LocalMemory and LocalArray, this class never adopts + * (takes ownership of) another array. + * + * WARNING: MaybeStackArray only works with primitive (plain-old data) types. + * It does NOT know how to call a destructor! If you work with classes with + * destructors, consider: + * + * - LocalArray in localpointer.h if you know the length ahead of time + * - MaybeStackVector if you know the length at runtime + */ +template<typename T, int32_t stackCapacity> +class MaybeStackArray { +public: + // No heap allocation. Use only on the stack. + static void* U_EXPORT2 operator new(size_t) noexcept = delete; + static void* U_EXPORT2 operator new[](size_t) noexcept = delete; +#if U_HAVE_PLACEMENT_NEW + static void* U_EXPORT2 operator new(size_t, void*) noexcept = delete; +#endif + + /** + * Default constructor initializes with internal T[stackCapacity] buffer. + */ + MaybeStackArray() : ptr(stackArray), capacity(stackCapacity), needToRelease(false) {} + /** + * Automatically allocates the heap array if the argument is larger than the stack capacity. + * Intended for use when an approximate capacity is known at compile time but the true + * capacity is not known until runtime. + */ + MaybeStackArray(int32_t newCapacity, UErrorCode status) : MaybeStackArray() { + if (U_FAILURE(status)) { + return; + } + if (capacity < newCapacity) { + if (resize(newCapacity) == nullptr) { + status = U_MEMORY_ALLOCATION_ERROR; + } + } + } + /** + * Destructor deletes the array (if owned). + */ + ~MaybeStackArray() { releaseArray(); } + /** + * Move constructor: transfers ownership or copies the stack array. + */ + MaybeStackArray(MaybeStackArray<T, stackCapacity> &&src) noexcept; + /** + * Move assignment: transfers ownership or copies the stack array. + */ + MaybeStackArray<T, stackCapacity> &operator=(MaybeStackArray<T, stackCapacity> &&src) noexcept; + /** + * Returns the array capacity (number of T items). + * @return array capacity + */ + int32_t getCapacity() const { return capacity; } + /** + * Access without ownership change. + * @return the array pointer + */ + T *getAlias() const { return ptr; } + /** + * Returns the array limit. Simple convenience method. + * @return getAlias()+getCapacity() + */ + T *getArrayLimit() const { return getAlias()+capacity; } + // No "operator T *() const" because that can make + // expressions like mbs[index] ambiguous for some compilers. + /** + * Array item access (const). + * No index bounds check. + * @param i array index + * @return reference to the array item + */ + const T &operator[](ptrdiff_t i) const { return ptr[i]; } + /** + * Array item access (writable). + * No index bounds check. + * @param i array index + * @return reference to the array item + */ + T &operator[](ptrdiff_t i) { return ptr[i]; } + /** + * Deletes the array (if owned) and aliases another one, no transfer of ownership. + * If the arguments are illegal, then the current array is unchanged. + * @param otherArray must not be nullptr + * @param otherCapacity must be >0 + */ + void aliasInstead(T *otherArray, int32_t otherCapacity) { + if(otherArray!=nullptr && otherCapacity>0) { + releaseArray(); + ptr=otherArray; + capacity=otherCapacity; + needToRelease=false; + } + } + /** + * Deletes the array (if owned) and allocates a new one, copying length T items. + * Returns the new array pointer. + * If the allocation fails, then the current array is unchanged and + * this method returns nullptr. + * @param newCapacity can be less than or greater than the current capacity; + * must be >0 + * @param length number of T items to be copied from the old array to the new one + * @return the allocated array pointer, or nullptr if the allocation failed + */ + inline T *resize(int32_t newCapacity, int32_t length=0); + /** + * Gives up ownership of the array if owned, or else clones it, + * copying length T items; resets itself to the internal stack array. + * Returns nullptr if the allocation failed. + * @param length number of T items to copy when cloning, + * and capacity of the clone when cloning + * @param resultCapacity will be set to the returned array's capacity (output-only) + * @return the array pointer; + * caller becomes responsible for deleting the array + */ + inline T *orphanOrClone(int32_t length, int32_t &resultCapacity); + +protected: + // Resizes the array to the size of src, then copies the contents of src. + void copyFrom(const MaybeStackArray &src, UErrorCode &status) { + if (U_FAILURE(status)) { + return; + } + if (this->resize(src.capacity, 0) == nullptr) { + status = U_MEMORY_ALLOCATION_ERROR; + return; + } + uprv_memcpy(this->ptr, src.ptr, (size_t)capacity * sizeof(T)); + } + +private: + T *ptr; + int32_t capacity; + UBool needToRelease; + T stackArray[stackCapacity]; + void releaseArray() { + if(needToRelease) { + uprv_free(ptr); + } + } + void resetToStackArray() { + ptr=stackArray; + capacity=stackCapacity; + needToRelease=false; + } + /* No comparison operators with other MaybeStackArray's. */ + bool operator==(const MaybeStackArray & /*other*/) = delete; + bool operator!=(const MaybeStackArray & /*other*/) = delete; + /* No ownership transfer: No copy constructor, no assignment operator. */ + MaybeStackArray(const MaybeStackArray & /*other*/) = delete; + void operator=(const MaybeStackArray & /*other*/) = delete; +}; + +template<typename T, int32_t stackCapacity> +icu::MaybeStackArray<T, stackCapacity>::MaybeStackArray( + MaybeStackArray <T, stackCapacity>&& src) noexcept + : ptr(src.ptr), capacity(src.capacity), needToRelease(src.needToRelease) { + if (src.ptr == src.stackArray) { + ptr = stackArray; + uprv_memcpy(stackArray, src.stackArray, sizeof(T) * src.capacity); + } else { + src.resetToStackArray(); // take ownership away from src + } +} + +template<typename T, int32_t stackCapacity> +inline MaybeStackArray <T, stackCapacity>& +MaybeStackArray<T, stackCapacity>::operator=(MaybeStackArray <T, stackCapacity>&& src) noexcept { + releaseArray(); // in case this instance had its own memory allocated + capacity = src.capacity; + needToRelease = src.needToRelease; + if (src.ptr == src.stackArray) { + ptr = stackArray; + uprv_memcpy(stackArray, src.stackArray, sizeof(T) * src.capacity); + } else { + ptr = src.ptr; + src.resetToStackArray(); // take ownership away from src + } + return *this; +} + +template<typename T, int32_t stackCapacity> +inline T *MaybeStackArray<T, stackCapacity>::resize(int32_t newCapacity, int32_t length) { + if(newCapacity>0) { +#if U_DEBUG && defined(UPRV_MALLOC_COUNT) + ::fprintf(::stderr, "MaybeStackArray (resize) alloc %d * %lu\n", newCapacity, sizeof(T)); +#endif + T *p=(T *)uprv_malloc(newCapacity*sizeof(T)); + if(p!=nullptr) { + if(length>0) { + if(length>capacity) { + length=capacity; + } + if(length>newCapacity) { + length=newCapacity; + } + uprv_memcpy(p, ptr, (size_t)length*sizeof(T)); + } + releaseArray(); + ptr=p; + capacity=newCapacity; + needToRelease=true; + } + return p; + } else { + return nullptr; + } +} + +template<typename T, int32_t stackCapacity> +inline T *MaybeStackArray<T, stackCapacity>::orphanOrClone(int32_t length, int32_t &resultCapacity) { + T *p; + if(needToRelease) { + p=ptr; + } else if(length<=0) { + return nullptr; + } else { + if(length>capacity) { + length=capacity; + } + p=(T *)uprv_malloc(length*sizeof(T)); +#if U_DEBUG && defined(UPRV_MALLOC_COUNT) + ::fprintf(::stderr,"MaybeStacArray (orphan) alloc %d * %lu\n", length,sizeof(T)); +#endif + if(p==nullptr) { + return nullptr; + } + uprv_memcpy(p, ptr, (size_t)length*sizeof(T)); + } + resultCapacity=length; + resetToStackArray(); + return p; +} + +/** + * Variant of MaybeStackArray that allocates a header struct and an array + * in one contiguous memory block, using uprv_malloc() and uprv_free(). + * Provides internal memory with fixed array capacity. Can alias another memory + * block or allocate one. + * The stackCapacity is the number of T items in the internal memory, + * not counting the H header. + * Unlike LocalMemory and LocalArray, this class never adopts + * (takes ownership of) another memory block. + */ +template<typename H, typename T, int32_t stackCapacity> +class MaybeStackHeaderAndArray { +public: + // No heap allocation. Use only on the stack. + static void* U_EXPORT2 operator new(size_t) noexcept = delete; + static void* U_EXPORT2 operator new[](size_t) noexcept = delete; +#if U_HAVE_PLACEMENT_NEW + static void* U_EXPORT2 operator new(size_t, void*) noexcept = delete; +#endif + + /** + * Default constructor initializes with internal H+T[stackCapacity] buffer. + */ + MaybeStackHeaderAndArray() : ptr(&stackHeader), capacity(stackCapacity), needToRelease(false) {} + /** + * Destructor deletes the memory (if owned). + */ + ~MaybeStackHeaderAndArray() { releaseMemory(); } + /** + * Returns the array capacity (number of T items). + * @return array capacity + */ + int32_t getCapacity() const { return capacity; } + /** + * Access without ownership change. + * @return the header pointer + */ + H *getAlias() const { return ptr; } + /** + * Returns the array start. + * @return array start, same address as getAlias()+1 + */ + T *getArrayStart() const { return reinterpret_cast<T *>(getAlias()+1); } + /** + * Returns the array limit. + * @return array limit + */ + T *getArrayLimit() const { return getArrayStart()+capacity; } + /** + * Access without ownership change. Same as getAlias(). + * A class instance can be used directly in expressions that take a T *. + * @return the header pointer + */ + operator H *() const { return ptr; } + /** + * Array item access (writable). + * No index bounds check. + * @param i array index + * @return reference to the array item + */ + T &operator[](ptrdiff_t i) { return getArrayStart()[i]; } + /** + * Deletes the memory block (if owned) and aliases another one, no transfer of ownership. + * If the arguments are illegal, then the current memory is unchanged. + * @param otherArray must not be nullptr + * @param otherCapacity must be >0 + */ + void aliasInstead(H *otherMemory, int32_t otherCapacity) { + if(otherMemory!=nullptr && otherCapacity>0) { + releaseMemory(); + ptr=otherMemory; + capacity=otherCapacity; + needToRelease=false; + } + } + /** + * Deletes the memory block (if owned) and allocates a new one, + * copying the header and length T array items. + * Returns the new header pointer. + * If the allocation fails, then the current memory is unchanged and + * this method returns nullptr. + * @param newCapacity can be less than or greater than the current capacity; + * must be >0 + * @param length number of T items to be copied from the old array to the new one + * @return the allocated pointer, or nullptr if the allocation failed + */ + inline H *resize(int32_t newCapacity, int32_t length=0); + /** + * Gives up ownership of the memory if owned, or else clones it, + * copying the header and length T array items; resets itself to the internal memory. + * Returns nullptr if the allocation failed. + * @param length number of T items to copy when cloning, + * and array capacity of the clone when cloning + * @param resultCapacity will be set to the returned array's capacity (output-only) + * @return the header pointer; + * caller becomes responsible for deleting the array + */ + inline H *orphanOrClone(int32_t length, int32_t &resultCapacity); +private: + H *ptr; + int32_t capacity; + UBool needToRelease; + // stackHeader must precede stackArray immediately. + H stackHeader; + T stackArray[stackCapacity]; + void releaseMemory() { + if(needToRelease) { + uprv_free(ptr); + } + } + /* No comparison operators with other MaybeStackHeaderAndArray's. */ + bool operator==(const MaybeStackHeaderAndArray & /*other*/) {return false;} + bool operator!=(const MaybeStackHeaderAndArray & /*other*/) {return true;} + /* No ownership transfer: No copy constructor, no assignment operator. */ + MaybeStackHeaderAndArray(const MaybeStackHeaderAndArray & /*other*/) {} + void operator=(const MaybeStackHeaderAndArray & /*other*/) {} +}; + +template<typename H, typename T, int32_t stackCapacity> +inline H *MaybeStackHeaderAndArray<H, T, stackCapacity>::resize(int32_t newCapacity, + int32_t length) { + if(newCapacity>=0) { +#if U_DEBUG && defined(UPRV_MALLOC_COUNT) + ::fprintf(::stderr,"MaybeStackHeaderAndArray alloc %d + %d * %ul\n", sizeof(H),newCapacity,sizeof(T)); +#endif + H *p=(H *)uprv_malloc(sizeof(H)+newCapacity*sizeof(T)); + if(p!=nullptr) { + if(length<0) { + length=0; + } else if(length>0) { + if(length>capacity) { + length=capacity; + } + if(length>newCapacity) { + length=newCapacity; + } + } + uprv_memcpy(p, ptr, sizeof(H)+(size_t)length*sizeof(T)); + releaseMemory(); + ptr=p; + capacity=newCapacity; + needToRelease=true; + } + return p; + } else { + return nullptr; + } +} + +template<typename H, typename T, int32_t stackCapacity> +inline H *MaybeStackHeaderAndArray<H, T, stackCapacity>::orphanOrClone(int32_t length, + int32_t &resultCapacity) { + H *p; + if(needToRelease) { + p=ptr; + } else { + if(length<0) { + length=0; + } else if(length>capacity) { + length=capacity; + } +#if U_DEBUG && defined(UPRV_MALLOC_COUNT) + ::fprintf(::stderr,"MaybeStackHeaderAndArray (orphan) alloc %ul + %d * %lu\n", sizeof(H),length,sizeof(T)); +#endif + p=(H *)uprv_malloc(sizeof(H)+length*sizeof(T)); + if(p==nullptr) { + return nullptr; + } + uprv_memcpy(p, ptr, sizeof(H)+(size_t)length*sizeof(T)); + } + resultCapacity=length; + ptr=&stackHeader; + capacity=stackCapacity; + needToRelease=false; + return p; +} + +/** + * A simple memory management class that creates new heap allocated objects (of + * any class that has a public constructor), keeps track of them and eventually + * deletes them all in its own destructor. + * + * A typical use-case would be code like this: + * + * MemoryPool<MyType> pool; + * + * MyType* o1 = pool.create(); + * if (o1 != nullptr) { + * foo(o1); + * } + * + * MyType* o2 = pool.create(1, 2, 3); + * if (o2 != nullptr) { + * bar(o2); + * } + * + * // MemoryPool will take care of deleting the MyType objects. + * + * It doesn't do anything more than that, and is intentionally kept minimalist. + */ +template<typename T, int32_t stackCapacity = 8> +class MemoryPool : public UMemory { +public: + MemoryPool() : fCount(0), fPool() {} + + ~MemoryPool() { + for (int32_t i = 0; i < fCount; ++i) { + delete fPool[i]; + } + } + + MemoryPool(const MemoryPool&) = delete; + MemoryPool& operator=(const MemoryPool&) = delete; + + MemoryPool(MemoryPool&& other) noexcept : fCount(other.fCount), + fPool(std::move(other.fPool)) { + other.fCount = 0; + } + + MemoryPool& operator=(MemoryPool&& other) noexcept { + // Since `this` may contain instances that need to be deleted, we can't + // just throw them away and replace them with `other`. The normal way of + // dealing with this in C++ is to swap `this` and `other`, rather than + // simply overwrite: the destruction of `other` can then take care of + // running MemoryPool::~MemoryPool() over the still-to-be-deallocated + // instances. + std::swap(fCount, other.fCount); + std::swap(fPool, other.fPool); + return *this; + } + + /** + * Creates a new object of typename T, by forwarding any and all arguments + * to the typename T constructor. + * + * @param args Arguments to be forwarded to the typename T constructor. + * @return A pointer to the newly created object, or nullptr on error. + */ + template<typename... Args> + T* create(Args&&... args) { + int32_t capacity = fPool.getCapacity(); + if (fCount == capacity && + fPool.resize(capacity == stackCapacity ? 4 * capacity : 2 * capacity, + capacity) == nullptr) { + return nullptr; + } + return fPool[fCount++] = new T(std::forward<Args>(args)...); + } + + template <typename... Args> + T* createAndCheckErrorCode(UErrorCode &status, Args &&... args) { + if (U_FAILURE(status)) { + return nullptr; + } + T *pointer = this->create(args...); + if (U_SUCCESS(status) && pointer == nullptr) { + status = U_MEMORY_ALLOCATION_ERROR; + } + return pointer; + } + + /** + * @return Number of elements that have been allocated. + */ + int32_t count() const { + return fCount; + } + +protected: + int32_t fCount; + MaybeStackArray<T*, stackCapacity> fPool; +}; + +/** + * An internal Vector-like implementation based on MemoryPool. + * + * Heap-allocates each element and stores pointers. + * + * To append an item to the vector, use emplaceBack. + * + * MaybeStackVector<MyType> vector; + * MyType* element = vector.emplaceBack(); + * if (!element) { + * status = U_MEMORY_ALLOCATION_ERROR; + * } + * // do stuff with element + * + * To loop over the vector, use a for loop with indices: + * + * for (int32_t i = 0; i < vector.length(); i++) { + * MyType* element = vector[i]; + * } + */ +template<typename T, int32_t stackCapacity = 8> +class MaybeStackVector : protected MemoryPool<T, stackCapacity> { +public: + template<typename... Args> + T* emplaceBack(Args&&... args) { + return this->create(args...); + } + + template <typename... Args> + T *emplaceBackAndCheckErrorCode(UErrorCode &status, Args &&... args) { + return this->createAndCheckErrorCode(status, args...); + } + + int32_t length() const { + return this->fCount; + } + + T** getAlias() { + return this->fPool.getAlias(); + } + + const T *const *getAlias() const { + return this->fPool.getAlias(); + } + + /** + * Array item access (read-only). + * No index bounds check. + * @param i array index + * @return reference to the array item + */ + const T* operator[](ptrdiff_t i) const { + return this->fPool[i]; + } + + /** + * Array item access (writable). + * No index bounds check. + * @param i array index + * @return reference to the array item + */ + T* operator[](ptrdiff_t i) { + return this->fPool[i]; + } +}; + + +U_NAMESPACE_END + +#endif /* __cplusplus */ +#endif /* CMEMORY_H */ |