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1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 | /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is C++ array template.
*
* The Initial Developer of the Original Code is Google Inc.
* Portions created by the Initial Developer are Copyright (C) 2005
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Darin Fisher <darin@meer.net>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef nsTArray_h__
#define nsTArray_h__
#include <string.h>
#include "prtypes.h"
#include "nsAlgorithm.h"
#include "nscore.h"
#include "nsQuickSort.h"
#include "nsDebug.h"
#include "nsTraceRefcnt.h"
#include "mozilla/Util.h"
#include NEW_H
//
// NB: nsTArray assumes that your "T" can be memmove()d. This is in
// contrast to STL containers, which follow C++
// construction/destruction rules.
//
// Don't use nsTArray if your "T" can't be memmove()d correctly.
//
//
// nsTArray*Allocators must all use the same |free()|, to allow
// swapping between fallible and infallible variants. (NS_Free() and
// moz_free() end up calling the same underlying free()).
//
#if defined(MOZALLOC_HAVE_XMALLOC)
struct nsTArrayFallibleAllocator
{
static void* Malloc(size_t size) {
return moz_malloc(size);
}
static void* Realloc(void* ptr, size_t size) {
return moz_realloc(ptr, size);
}
static void Free(void* ptr) {
moz_free(ptr);
}
};
struct nsTArrayInfallibleAllocator
{
static void* Malloc(size_t size) {
return moz_xmalloc(size);
}
static void* Realloc(void* ptr, size_t size) {
return moz_xrealloc(ptr, size);
}
static void Free(void* ptr) {
moz_free(ptr);
}
};
#else
#include <stdlib.h>
struct nsTArrayFallibleAllocator
{
static void* Malloc(size_t size) {
return malloc(size);
}
static void* Realloc(void* ptr, size_t size) {
return realloc(ptr, size);
}
static void Free(void* ptr) {
free(ptr);
}
};
#endif
#if defined(MOZALLOC_HAVE_XMALLOC)
struct nsTArrayDefaultAllocator : public nsTArrayInfallibleAllocator { };
#else
struct nsTArrayDefaultAllocator : public nsTArrayFallibleAllocator { };
#endif
// nsTArray_base stores elements into the space allocated beyond
// sizeof(*this). This is done to minimize the size of the nsTArray
// object when it is empty.
struct NS_COM_GLUE nsTArrayHeader
{
static nsTArrayHeader sEmptyHdr;
PRUint32 mLength;
PRUint32 mCapacity : 31;
PRUint32 mIsAutoArray : 1;
};
// This class provides a SafeElementAt method to nsTArray<T*> which does
// not take a second default value parameter.
template <class E, class Derived>
struct nsTArray_SafeElementAtHelper
{
typedef E* elem_type;
typedef PRUint32 index_type;
// No implementation is provided for these two methods, and that is on
// purpose, since we don't support these functions on non-pointer type
// instantiations.
elem_type& SafeElementAt(index_type i);
const elem_type& SafeElementAt(index_type i) const;
};
template <class E, class Derived>
struct nsTArray_SafeElementAtHelper<E*, Derived>
{
typedef E* elem_type;
typedef PRUint32 index_type;
elem_type SafeElementAt(index_type i) {
return static_cast<Derived*> (this)->SafeElementAt(i, nsnull);
}
const elem_type SafeElementAt(index_type i) const {
return static_cast<const Derived*> (this)->SafeElementAt(i, nsnull);
}
};
// E is the base type that the smart pointer is templated over; the
// smart pointer can act as E*.
template <class E, class Derived>
struct nsTArray_SafeElementAtSmartPtrHelper
{
typedef E* elem_type;
typedef PRUint32 index_type;
elem_type SafeElementAt(index_type i) {
return static_cast<Derived*> (this)->SafeElementAt(i, nsnull);
}
const elem_type SafeElementAt(index_type i) const {
return static_cast<const Derived*> (this)->SafeElementAt(i, nsnull);
}
};
template <class T> class nsCOMPtr;
template <class E, class Derived>
struct nsTArray_SafeElementAtHelper<nsCOMPtr<E>, Derived> :
public nsTArray_SafeElementAtSmartPtrHelper<E, Derived>
{
};
template <class T> class nsRefPtr;
template <class E, class Derived>
struct nsTArray_SafeElementAtHelper<nsRefPtr<E>, Derived> :
public nsTArray_SafeElementAtSmartPtrHelper<E, Derived>
{
};
//
// This class serves as a base class for nsTArray. It shouldn't be used
// directly. It holds common implementation code that does not depend on the
// element type of the nsTArray.
//
template<class Alloc>
class nsTArray_base
{
// Allow swapping elements with |nsTArray_base|s created using a
// different allocator. This is kosher because all allocators use
// the same free().
template<class Allocator>
friend class nsTArray_base;
protected:
typedef nsTArrayHeader Header;
public:
typedef PRUint32 size_type;
typedef PRUint32 index_type;
// @return The number of elements in the array.
size_type Length() const {
return mHdr->mLength;
}
// @return True if the array is empty or false otherwise.
bool IsEmpty() const {
return Length() == 0;
}
// @return The number of elements that can fit in the array without forcing
// the array to be re-allocated. The length of an array is always less
// than or equal to its capacity.
size_type Capacity() const {
return mHdr->mCapacity;
}
#ifdef DEBUG
void* DebugGetHeader() const {
return mHdr;
}
#endif
protected:
nsTArray_base();
~nsTArray_base();
// Resize the storage if necessary to achieve the requested capacity.
// @param capacity The requested number of array elements.
// @param elemSize The size of an array element.
// @return False if insufficient memory is available; true otherwise.
bool EnsureCapacity(size_type capacity, size_type elemSize);
// Resize the storage to the minimum required amount.
// @param elemSize The size of an array element.
// @param elemAlign The alignment in bytes of an array element.
void ShrinkCapacity(size_type elemSize, size_t elemAlign);
// This method may be called to resize a "gap" in the array by shifting
// elements around. It updates mLength appropriately. If the resulting
// array has zero elements, then the array's memory is free'd.
// @param start The starting index of the gap.
// @param oldLen The current length of the gap.
// @param newLen The desired length of the gap.
// @param elemSize The size of an array element.
// @param elemAlign The alignment in bytes of an array element.
void ShiftData(index_type start, size_type oldLen, size_type newLen,
size_type elemSize, size_t elemAlign);
// This method increments the length member of the array's header.
// Note that mHdr may actually be sEmptyHdr in the case where a
// zero-length array is inserted into our array. But then n should
// always be 0.
void IncrementLength(PRUint32 n) {
NS_ASSERTION(mHdr != EmptyHdr() || n == 0, "bad data pointer");
mHdr->mLength += n;
}
// This method inserts blank slots into the array.
// @param index the place to insert the new elements. This must be no
// greater than the current length of the array.
// @param count the number of slots to insert
// @param elementSize the size of an array element.
// @param elemAlign the alignment in bytes of an array element.
bool InsertSlotsAt(index_type index, size_type count,
size_type elementSize, size_t elemAlign);
protected:
template<class Allocator>
bool SwapArrayElements(nsTArray_base<Allocator>& other,
size_type elemSize,
size_t elemAlign);
// This is an RAII class used in SwapArrayElements.
class IsAutoArrayRestorer {
public:
IsAutoArrayRestorer(nsTArray_base<Alloc> &array, size_t elemAlign);
~IsAutoArrayRestorer();
private:
nsTArray_base<Alloc> &mArray;
size_t mElemAlign;
bool mIsAuto;
};
// Helper function for SwapArrayElements. Ensures that if the array
// is an nsAutoTArray that it doesn't use the built-in buffer.
bool EnsureNotUsingAutoArrayBuffer(size_type elemSize);
// Returns true if this nsTArray is an nsAutoTArray with a built-in buffer.
bool IsAutoArray() const {
return mHdr->mIsAutoArray;
}
// Returns a Header for the built-in buffer of this nsAutoTArray.
Header* GetAutoArrayBuffer(size_t elemAlign) {
NS_ASSERTION(IsAutoArray(), "Should be an auto array to call this");
return GetAutoArrayBufferUnsafe(elemAlign);
}
const Header* GetAutoArrayBuffer(size_t elemAlign) const {
NS_ASSERTION(IsAutoArray(), "Should be an auto array to call this");
return GetAutoArrayBufferUnsafe(elemAlign);
}
// Returns a Header for the built-in buffer of this nsAutoTArray, but doesn't
// assert that we are an nsAutoTArray.
Header* GetAutoArrayBufferUnsafe(size_t elemAlign) {
return const_cast<Header*>(static_cast<const nsTArray_base<Alloc>*>(this)->
GetAutoArrayBufferUnsafe(elemAlign));
}
const Header* GetAutoArrayBufferUnsafe(size_t elemAlign) const;
// Returns true if this is an nsAutoTArray and it currently uses the
// built-in buffer to store its elements.
bool UsesAutoArrayBuffer() const;
// The array's elements (prefixed with a Header). This pointer is never
// null. If the array is empty, then this will point to sEmptyHdr.
Header *mHdr;
Header* Hdr() const {
return mHdr;
}
Header** PtrToHdr() {
return &mHdr;
}
static Header* EmptyHdr() {
return &Header::sEmptyHdr;
}
};
//
// This class defines convenience functions for element specific operations.
// Specialize this template if necessary.
//
template<class E>
class nsTArrayElementTraits
{
public:
// Invoke the default constructor in place.
static inline void Construct(E *e) {
// Do NOT call "E()"! That triggers C++ "default initialization"
// which zeroes out POD ("plain old data") types such as regular
// ints. We don't want that because it can be a performance issue
// and people don't expect it; nsTArray should work like a regular
// C/C++ array in this respect.
new (static_cast<void *>(e)) E;
}
// Invoke the copy-constructor in place.
template<class A>
static inline void Construct(E *e, const A &arg) {
new (static_cast<void *>(e)) E(arg);
}
// Invoke the destructor in place.
static inline void Destruct(E *e) {
e->~E();
}
};
// This class exists because VC6 cannot handle static template functions.
// Otherwise, the Compare method would be defined directly on nsTArray.
template <class E, class Comparator>
class nsQuickSortComparator
{
public:
typedef E elem_type;
// This function is meant to be used with the NS_QuickSort function. It
// maps the callback API expected by NS_QuickSort to the Comparator API
// used by nsTArray. See nsTArray::Sort.
static int Compare(const void* e1, const void* e2, void *data) {
const Comparator* c = reinterpret_cast<const Comparator*>(data);
const elem_type* a = static_cast<const elem_type*>(e1);
const elem_type* b = static_cast<const elem_type*>(e2);
return c->LessThan(*a, *b) ? -1 : (c->Equals(*a, *b) ? 0 : 1);
}
};
// The default comparator used by nsTArray
template<class A, class B>
class nsDefaultComparator
{
public:
bool Equals(const A& a, const B& b) const {
return a == b;
}
bool LessThan(const A& a, const B& b) const {
return a < b;
}
};
//
// The templatized array class that dynamically resizes its storage as
// elements are added. This class is designed to behave a bit like
// std::vector, though note that unlike std::vector, nsTArray doesn't
// follow C++ construction/destruction rules.
//
// The template parameter specifies the type of the elements (elem_type), and
// has the following requirements:
//
// elem_type MUST define a copy-constructor.
// elem_type MAY define operator< for sorting.
// elem_type MAY define operator== for searching.
//
// For methods taking a Comparator instance, the Comparator must be a class
// defining the following methods:
//
// class Comparator {
// public:
// /** @return True if the elements are equals; false otherwise. */
// bool Equals(const elem_type& a, const Item& b) const;
//
// /** @return True if (a < b); false otherwise. */
// bool LessThan(const elem_type& a, const Item& b) const;
// };
//
// The Equals method is used for searching, and the LessThan method is used
// for sorting. The |Item| type above can be arbitrary, but must match the
// Item type passed to the sort or search function.
//
// The Alloc template parameter can be used to choose between
// "fallible" and "infallible" nsTArray (if available), defaulting to
// fallible. If the *fallible* allocator is used, the return value of
// methods that might allocate needs to be checked; Append() is
// one such method. These return values don't need to be checked if
// the *in*fallible allocator is chosen. When in doubt, choose the
// infallible allocator.
//
template<class E, class Alloc=nsTArrayDefaultAllocator>
class nsTArray : public nsTArray_base<Alloc>,
public nsTArray_SafeElementAtHelper<E, nsTArray<E, Alloc> >
{
public:
typedef nsTArray_base<Alloc> base_type;
typedef typename base_type::size_type size_type;
typedef typename base_type::index_type index_type;
typedef E elem_type;
typedef nsTArray<E, Alloc> self_type;
typedef nsTArrayElementTraits<E> elem_traits;
typedef nsTArray_SafeElementAtHelper<E, self_type> safeelementat_helper_type;
using safeelementat_helper_type::SafeElementAt;
using base_type::EmptyHdr;
// A special value that is used to indicate an invalid or unknown index
// into the array.
enum {
NoIndex = index_type(-1)
};
using base_type::Length;
//
// Finalization method
//
~nsTArray() { Clear(); }
//
// Initialization methods
//
nsTArray() {}
// Initialize this array and pre-allocate some number of elements.
explicit nsTArray(size_type capacity) {
SetCapacity(capacity);
}
// The array's copy-constructor performs a 'deep' copy of the given array.
// @param other The array object to copy.
nsTArray(const self_type& other) {
AppendElements(other);
}
template<typename Allocator>
nsTArray(const nsTArray<E, Allocator>& other) {
AppendElements(other);
}
// The array's assignment operator performs a 'deep' copy of the given
// array. It is optimized to reuse existing storage if possible.
// @param other The array object to copy.
nsTArray& operator=(const self_type& other) {
ReplaceElementsAt(0, Length(), other.Elements(), other.Length());
return *this;
}
// Return true if this array has the same length and the same
// elements as |other|.
bool operator==(const self_type& other) const {
size_type len = Length();
if (len != other.Length())
return false;
// XXX std::equal would be as fast or faster here
for (index_type i = 0; i < len; ++i)
if (!(operator[](i) == other[i]))
return false;
return true;
}
// Return true if this array does not have the same length and the same
// elements as |other|.
bool operator!=(const self_type& other) const {
return !operator==(other);
}
template<typename Allocator>
nsTArray& operator=(const nsTArray<E, Allocator>& other) {
ReplaceElementsAt(0, Length(), other.Elements(), other.Length());
return *this;
}
// @return The amount of memory used by this nsTArray, excluding
// sizeof(*this).
size_t SizeOfExcludingThis(nsMallocSizeOfFun mallocSizeOf) const {
if (this->UsesAutoArrayBuffer() || Hdr() == EmptyHdr())
return 0;
return mallocSizeOf(this->Hdr(),
sizeof(nsTArrayHeader) +
this->Capacity() * sizeof(elem_type));
}
// @return The amount of memory used by this nsTArray, including
// sizeof(*this).
size_t SizeOfIncludingThis(nsMallocSizeOfFun mallocSizeOf) const {
return mallocSizeOf(this, sizeof(nsTArray)) +
SizeOfExcludingThis(mallocSizeOf);
}
//
// Accessor methods
//
// This method provides direct access to the array elements.
// @return A pointer to the first element of the array. If the array is
// empty, then this pointer must not be dereferenced.
elem_type* Elements() {
return reinterpret_cast<elem_type *>(Hdr() + 1);
}
// This method provides direct, readonly access to the array elements.
// @return A pointer to the first element of the array. If the array is
// empty, then this pointer must not be dereferenced.
const elem_type* Elements() const {
return reinterpret_cast<const elem_type *>(Hdr() + 1);
}
// This method provides direct access to the i'th element of the array.
// The given index must be within the array bounds.
// @param i The index of an element in the array.
// @return A reference to the i'th element of the array.
elem_type& ElementAt(index_type i) {
NS_ASSERTION(i < Length(), "invalid array index");
return Elements()[i];
}
// This method provides direct, readonly access to the i'th element of the
// array. The given index must be within the array bounds.
// @param i The index of an element in the array.
// @return A const reference to the i'th element of the array.
const elem_type& ElementAt(index_type i) const {
NS_ASSERTION(i < Length(), "invalid array index");
return Elements()[i];
}
// This method provides direct access to the i'th element of the array in
// a bounds safe manner. If the requested index is out of bounds the
// provided default value is returned.
// @param i The index of an element in the array.
// @param def The value to return if the index is out of bounds.
elem_type& SafeElementAt(index_type i, elem_type& def) {
return i < Length() ? Elements()[i] : def;
}
// This method provides direct access to the i'th element of the array in
// a bounds safe manner. If the requested index is out of bounds the
// provided default value is returned.
// @param i The index of an element in the array.
// @param def The value to return if the index is out of bounds.
const elem_type& SafeElementAt(index_type i, const elem_type& def) const {
return i < Length() ? Elements()[i] : def;
}
// Shorthand for ElementAt(i)
elem_type& operator[](index_type i) {
return ElementAt(i);
}
// Shorthand for ElementAt(i)
const elem_type& operator[](index_type i) const {
return ElementAt(i);
}
//
// Search methods
//
// This method searches for the first element in this array that is equal
// to the given element.
// @param item The item to search for.
// @param comp The Comparator used to determine element equality.
// @return true if the element was found.
template<class Item, class Comparator>
bool Contains(const Item& item, const Comparator& comp) const {
return IndexOf(item, 0, comp) != NoIndex;
}
// This method searches for the first element in this array that is equal
// to the given element. This method assumes that 'operator==' is defined
// for elem_type.
// @param item The item to search for.
// @return true if the element was found.
template<class Item>
bool Contains(const Item& item) const {
return IndexOf(item) != NoIndex;
}
// This method searches for the offset of the first element in this
// array that is equal to the given element.
// @param item The item to search for.
// @param start The index to start from.
// @param comp The Comparator used to determine element equality.
// @return The index of the found element or NoIndex if not found.
template<class Item, class Comparator>
index_type IndexOf(const Item& item, index_type start,
const Comparator& comp) const {
const elem_type* iter = Elements() + start, *end = Elements() + Length();
for (; iter != end; ++iter) {
if (comp.Equals(*iter, item))
return index_type(iter - Elements());
}
return NoIndex;
}
// This method searches for the offset of the first element in this
// array that is equal to the given element. This method assumes
// that 'operator==' is defined for elem_type.
// @param item The item to search for.
// @param start The index to start from.
// @return The index of the found element or NoIndex if not found.
template<class Item>
index_type IndexOf(const Item& item, index_type start = 0) const {
return IndexOf(item, start, nsDefaultComparator<elem_type, Item>());
}
// This method searches for the offset of the last element in this
// array that is equal to the given element.
// @param item The item to search for.
// @param start The index to start from. If greater than or equal to the
// length of the array, then the entire array is searched.
// @param comp The Comparator used to determine element equality.
// @return The index of the found element or NoIndex if not found.
template<class Item, class Comparator>
index_type LastIndexOf(const Item& item, index_type start,
const Comparator& comp) const {
if (start >= Length())
start = Length() - 1;
const elem_type* end = Elements() - 1, *iter = end + start + 1;
for (; iter != end; --iter) {
if (comp.Equals(*iter, item))
return index_type(iter - Elements());
}
return NoIndex;
}
// This method searches for the offset of the last element in this
// array that is equal to the given element. This method assumes
// that 'operator==' is defined for elem_type.
// @param item The item to search for.
// @param start The index to start from. If greater than or equal to the
// length of the array, then the entire array is searched.
// @return The index of the found element or NoIndex if not found.
template<class Item>
index_type LastIndexOf(const Item& item,
index_type start = NoIndex) const {
return LastIndexOf(item, start, nsDefaultComparator<elem_type, Item>());
}
// This method searches for the offset for the element in this array
// that is equal to the given element. The array is assumed to be sorted.
// @param item The item to search for.
// @param comp The Comparator used.
// @return The index of the found element or NoIndex if not found.
template<class Item, class Comparator>
index_type BinaryIndexOf(const Item& item, const Comparator& comp) const {
index_type low = 0, high = Length();
while (high > low) {
index_type mid = (high + low) >> 1;
if (comp.Equals(ElementAt(mid), item))
return mid;
if (comp.LessThan(ElementAt(mid), item))
low = mid + 1;
else
high = mid;
}
return NoIndex;
}
// This method searches for the offset for the element in this array
// that is equal to the given element. The array is assumed to be sorted.
// This method assumes that 'operator==' and 'operator<' are defined.
// @param item The item to search for.
// @return The index of the found element or NoIndex if not found.
template<class Item>
index_type BinaryIndexOf(const Item& item) const {
return BinaryIndexOf(item, nsDefaultComparator<elem_type, Item>());
}
//
// Mutation methods
//
// This method replaces a range of elements in this array.
// @param start The starting index of the elements to replace.
// @param count The number of elements to replace. This may be zero to
// insert elements without removing any existing elements.
// @param array The values to copy into this array. Must be non-null,
// and these elements must not already exist in the array
// being modified.
// @param arrayLen The number of values to copy into this array.
// @return A pointer to the new elements in the array, or null if
// the operation failed due to insufficient memory.
template<class Item>
elem_type *ReplaceElementsAt(index_type start, size_type count,
const Item* array, size_type arrayLen) {
// Adjust memory allocation up-front to catch errors.
if (!this->EnsureCapacity(Length() + arrayLen - count, sizeof(elem_type)))
return nsnull;
DestructRange(start, count);
this->ShiftData(start, count, arrayLen, sizeof(elem_type), MOZ_ALIGNOF(elem_type));
AssignRange(start, arrayLen, array);
return Elements() + start;
}
// A variation on the ReplaceElementsAt method defined above.
template<class Item>
elem_type *ReplaceElementsAt(index_type start, size_type count,
const nsTArray<Item>& array) {
return ReplaceElementsAt(start, count, array.Elements(), array.Length());
}
// A variation on the ReplaceElementsAt method defined above.
template<class Item>
elem_type *ReplaceElementsAt(index_type start, size_type count,
const Item& item) {
return ReplaceElementsAt(start, count, &item, 1);
}
// A variation on the ReplaceElementsAt method defined above.
template<class Item>
elem_type *ReplaceElementAt(index_type index, const Item& item) {
return ReplaceElementsAt(index, 1, item, 1);
}
// A variation on the ReplaceElementsAt method defined above.
template<class Item>
elem_type *InsertElementsAt(index_type index, const Item* array,
size_type arrayLen) {
return ReplaceElementsAt(index, 0, array, arrayLen);
}
// A variation on the ReplaceElementsAt method defined above.
template<class Item>
elem_type *InsertElementsAt(index_type index, const nsTArray<Item>& array) {
return ReplaceElementsAt(index, 0, array.Elements(), array.Length());
}
// A variation on the ReplaceElementsAt method defined above.
template<class Item>
elem_type *InsertElementAt(index_type index, const Item& item) {
return ReplaceElementsAt(index, 0, &item, 1);
}
// Insert a new element without copy-constructing. This is useful to avoid
// temporaries.
// @return A pointer to the newly inserted element, or null on OOM.
elem_type* InsertElementAt(index_type index) {
if (!this->EnsureCapacity(Length() + 1, sizeof(elem_type)))
return nsnull;
this->ShiftData(index, 0, 1, sizeof(elem_type), MOZ_ALIGNOF(elem_type));
elem_type *elem = Elements() + index;
elem_traits::Construct(elem);
return elem;
}
// This method searches for the least index of the greatest
// element less than or equal to |item|. If |item| is inserted at
// this index, the array will remain sorted. True is returned iff
// this index is also equal to |item|. In this case, the returned
// index may point to the start of multiple copies of |item|.
// @param item The item to search for.
// @param comp The Comparator used.
// @outparam idx The index of greatest element <= to |item|
// @return True iff |item == array[*idx]|.
// @precondition The array is sorted
template<class Item, class Comparator>
bool
GreatestIndexLtEq(const Item& item,
const Comparator& comp,
index_type* idx NS_OUTPARAM) const {
// Nb: we could replace all the uses of "BinaryIndexOf" with this
// function, but BinaryIndexOf will be oh-so-slightly faster so
// it's not strictly desired to do.
// invariant: low <= [idx] < high
index_type low = 0, high = Length();
while (high > low) {
index_type mid = (high + low) >> 1;
if (comp.Equals(ElementAt(mid), item)) {
// we might have the array [..., 2, 4, 4, 4, 4, 4, 5, ...]
// and be searching for "4". it's arbitrary where mid ends
// up here, so we back it up to the first instance to maintain
// the "least index ..." we promised above.
do {
--mid;
} while (NoIndex != mid && comp.Equals(ElementAt(mid), item));
*idx = ++mid;
return true;
}
if (comp.LessThan(ElementAt(mid), item))
// invariant: low <= idx < high
low = mid + 1;
else
// invariant: low <= idx < high
high = mid;
}
// low <= idx < high, so insert at high ("shifting" high up by
// 1) to maintain invariant.
// (or insert at low, since low==high; just a matter of taste here.)
*idx = high;
return false;
}
// A variation on the GreatestIndexLtEq method defined above.
template<class Item, class Comparator>
bool
GreatestIndexLtEq(const Item& item,
index_type& idx,
const Comparator& comp) const {
return GreatestIndexLtEq(item, comp, &idx);
}
// A variation on the GreatestIndexLtEq method defined above.
template<class Item>
bool
GreatestIndexLtEq(const Item& item,
index_type& idx) const {
return GreatestIndexLtEq(item, nsDefaultComparator<elem_type, Item>(), &idx);
}
// Inserts |item| at such an index to guarantee that if the array
// was previously sorted, it will remain sorted after this
// insertion.
template<class Item, class Comparator>
elem_type *InsertElementSorted(const Item& item, const Comparator& comp) {
index_type index;
GreatestIndexLtEq(item, comp, &index);
return InsertElementAt(index, item);
}
// A variation on the InsertElementSorted metod defined above.
template<class Item>
elem_type *InsertElementSorted(const Item& item) {
return InsertElementSorted(item, nsDefaultComparator<elem_type, Item>());
}
// This method appends elements to the end of this array.
// @param array The elements to append to this array.
// @param arrayLen The number of elements to append to this array.
// @return A pointer to the new elements in the array, or null if
// the operation failed due to insufficient memory.
template<class Item>
elem_type *AppendElements(const Item* array, size_type arrayLen) {
if (!this->EnsureCapacity(Length() + arrayLen, sizeof(elem_type)))
return nsnull;
index_type len = Length();
AssignRange(len, arrayLen, array);
this->IncrementLength(arrayLen);
return Elements() + len;
}
// A variation on the AppendElements method defined above.
template<class Item, class Allocator>
elem_type *AppendElements(const nsTArray<Item, Allocator>& array) {
return AppendElements(array.Elements(), array.Length());
}
// A variation on the AppendElements method defined above.
template<class Item>
elem_type *AppendElement(const Item& item) {
return AppendElements(&item, 1);
}
// Append new elements without copy-constructing. This is useful to avoid
// temporaries.
// @return A pointer to the newly appended elements, or null on OOM.
elem_type *AppendElements(size_type count) {
if (!this->EnsureCapacity(Length() + count, sizeof(elem_type)))
return nsnull;
elem_type *elems = Elements() + Length();
size_type i;
for (i = 0; i < count; ++i) {
elem_traits::Construct(elems + i);
}
this->IncrementLength(count);
return elems;
}
// Append a new element without copy-constructing. This is useful to avoid
// temporaries.
// @return A pointer to the newly appended element, or null on OOM.
elem_type *AppendElement() {
return AppendElements(1);
}
// Move all elements from another array to the end of this array without
// calling copy constructors or destructors.
// @return A pointer to the newly appended elements, or null on OOM.
template<class Item, class Allocator>
elem_type *MoveElementsFrom(nsTArray<Item, Allocator>& array) {
NS_PRECONDITION(&array != this, "argument must be different array");
index_type len = Length();
index_type otherLen = array.Length();
if (!this->EnsureCapacity(len + otherLen, sizeof(elem_type)))
return nsnull;
memcpy(Elements() + len, array.Elements(), otherLen * sizeof(elem_type));
this->IncrementLength(otherLen);
array.ShiftData(0, otherLen, 0, sizeof(elem_type), MOZ_ALIGNOF(elem_type));
return Elements() + len;
}
// This method removes a range of elements from this array.
// @param start The starting index of the elements to remove.
// @param count The number of elements to remove.
void RemoveElementsAt(index_type start, size_type count) {
NS_ASSERTION(count == 0 || start < Length(), "Invalid start index");
NS_ASSERTION(start + count <= Length(), "Invalid length");
DestructRange(start, count);
this->ShiftData(start, count, 0, sizeof(elem_type), MOZ_ALIGNOF(elem_type));
}
// A variation on the RemoveElementsAt method defined above.
void RemoveElementAt(index_type index) {
RemoveElementsAt(index, 1);
}
// A variation on the RemoveElementsAt method defined above.
void Clear() {
RemoveElementsAt(0, Length());
}
// This helper function combines IndexOf with RemoveElementAt to "search
// and destroy" the first element that is equal to the given element.
// @param item The item to search for.
// @param comp The Comparator used to determine element equality.
// @return true if the element was found
template<class Item, class Comparator>
bool RemoveElement(const Item& item, const Comparator& comp) {
index_type i = IndexOf(item, 0, comp);
if (i == NoIndex)
return false;
RemoveElementAt(i);
return true;
}
// A variation on the RemoveElement method defined above that assumes
// that 'operator==' is defined for elem_type.
template<class Item>
bool RemoveElement(const Item& item) {
return RemoveElement(item, nsDefaultComparator<elem_type, Item>());
}
// This helper function combines GreatestIndexLtEq with
// RemoveElementAt to "search and destroy" the first element that
// is equal to the given element.
// @param item The item to search for.
// @param comp The Comparator used to determine element equality.
// @return true if the element was found
template<class Item, class Comparator>
bool RemoveElementSorted(const Item& item, const Comparator& comp) {
index_type index;
bool found = GreatestIndexLtEq(item, comp, &index);
if (found)
RemoveElementAt(index);
return found;
}
// A variation on the RemoveElementSorted method defined above.
template<class Item>
bool RemoveElementSorted(const Item& item) {
return RemoveElementSorted(item, nsDefaultComparator<elem_type, Item>());
}
// This method causes the elements contained in this array and the given
// array to be swapped.
template<class Allocator>
bool SwapElements(nsTArray<E, Allocator>& other) {
return this->SwapArrayElements(other, sizeof(elem_type), MOZ_ALIGNOF(elem_type));
}
//
// Allocation
//
// This method may increase the capacity of this array object by the
// specified amount. This method may be called in advance of several
// AppendElement operations to minimize heap re-allocations. This method
// will not reduce the number of elements in this array.
// @param capacity The desired capacity of this array.
// @return True if the operation succeeded; false if we ran out of memory
bool SetCapacity(size_type capacity) {
return this->EnsureCapacity(capacity, sizeof(elem_type));
}
// This method modifies the length of the array. If the new length is
// larger than the existing length of the array, then new elements will be
// constructed using elem_type's default constructor. Otherwise, this call
// removes elements from the array (see also RemoveElementsAt).
// @param newLen The desired length of this array.
// @return True if the operation succeeded; false otherwise.
// See also TruncateLength if the new length is guaranteed to be
// smaller than the old.
bool SetLength(size_type newLen) {
size_type oldLen = Length();
if (newLen > oldLen) {
return InsertElementsAt(oldLen, newLen - oldLen) != nsnull;
}
TruncateLength(newLen);
return true;
}
// This method modifies the length of the array, but may only be
// called when the new length is shorter than the old. It can
// therefore be called when elem_type has no default constructor,
// unlike SetLength. It removes elements from the array (see also
// RemoveElementsAt).
// @param newLen The desired length of this array.
void TruncateLength(size_type newLen) {
size_type oldLen = Length();
NS_ABORT_IF_FALSE(newLen <= oldLen,
"caller should use SetLength instead");
RemoveElementsAt(newLen, oldLen - newLen);
}
// This method ensures that the array has length at least the given
// length. If the current length is shorter than the given length,
// then new elements will be constructed using elem_type's default
// constructor.
// @param minLen The desired minimum length of this array.
// @return True if the operation succeeded; false otherwise.
bool EnsureLengthAtLeast(size_type minLen) {
size_type oldLen = Length();
if (minLen > oldLen) {
return InsertElementsAt(oldLen, minLen - oldLen) != nsnull;
}
return true;
}
// This method inserts elements into the array, constructing
// them using elem_type's default constructor.
// @param index the place to insert the new elements. This must be no
// greater than the current length of the array.
// @param count the number of elements to insert
elem_type *InsertElementsAt(index_type index, size_type count) {
if (!base_type::InsertSlotsAt(index, count, sizeof(elem_type), MOZ_ALIGNOF(elem_type))) {
return nsnull;
}
// Initialize the extra array elements
elem_type *iter = Elements() + index, *end = iter + count;
for (; iter != end; ++iter) {
elem_traits::Construct(iter);
}
return Elements() + index;
}
// This method inserts elements into the array, constructing them
// elem_type's copy constructor (or whatever one-arg constructor
// happens to match the Item type).
// @param index the place to insert the new elements. This must be no
// greater than the current length of the array.
// @param count the number of elements to insert.
// @param item the value to use when constructing the new elements.
template<class Item>
elem_type *InsertElementsAt(index_type index, size_type count,
const Item& item) {
if (!base_type::InsertSlotsAt(index, count, sizeof(elem_type), MOZ_ALIGNOF(elem_type))) {
return nsnull;
}
// Initialize the extra array elements
elem_type *iter = Elements() + index, *end = iter + count;
for (; iter != end; ++iter) {
elem_traits::Construct(iter, item);
}
return Elements() + index;
}
// This method may be called to minimize the memory used by this array.
void Compact() {
ShrinkCapacity(sizeof(elem_type), MOZ_ALIGNOF(elem_type));
}
//
// Sorting
//
// This method sorts the elements of the array. It uses the LessThan
// method defined on the given Comparator object to collate elements.
// @param comp The Comparator used to collate elements.
template<class Comparator>
void Sort(const Comparator& comp) {
NS_QuickSort(Elements(), Length(), sizeof(elem_type),
nsQuickSortComparator<elem_type, Comparator>::Compare,
const_cast<Comparator*>(&comp));
}
// A variation on the Sort method defined above that assumes that
// 'operator<' is defined for elem_type.
void Sort() {
Sort(nsDefaultComparator<elem_type, elem_type>());
}
//
// Binary Heap
//
// Sorts the array into a binary heap.
// @param comp The Comparator used to create the heap
template<class Comparator>
void MakeHeap(const Comparator& comp) {
if (!Length()) {
return;
}
index_type index = (Length() - 1) / 2;
do {
SiftDown(index, comp);
} while (index--);
}
// A variation on the MakeHeap method defined above.
void MakeHeap() {
MakeHeap(nsDefaultComparator<elem_type, elem_type>());
}
// Adds an element to the heap
// @param item The item to add
// @param comp The Comparator used to sift-up the item
template<class Item, class Comparator>
elem_type *PushHeap(const Item& item, const Comparator& comp) {
if (!base_type::InsertSlotsAt(Length(), 1, sizeof(elem_type), MOZ_ALIGNOF(elem_type))) {
return nsnull;
}
// Sift up the new node
elem_type *elem = Elements();
index_type index = Length() - 1;
index_type parent_index = (index - 1) / 2;
while (index && comp.LessThan(elem[parent_index], item)) {
elem[index] = elem[parent_index];
index = parent_index;
parent_index = (index - 1) / 2;
}
elem[index] = item;
return &elem[index];
}
// A variation on the PushHeap method defined above.
template<class Item>
elem_type *PushHeap(const Item& item) {
return PushHeap(item, nsDefaultComparator<elem_type, Item>());
}
// Delete the root of the heap and restore the heap
// @param comp The Comparator used to restore the heap
template<class Comparator>
void PopHeap(const Comparator& comp) {
if (!Length()) {
return;
}
index_type last_index = Length() - 1;
elem_type *elem = Elements();
elem[0] = elem[last_index];
TruncateLength(last_index);
if (Length()) {
SiftDown(0, comp);
}
}
// A variation on the PopHeap method defined above.
void PopHeap() {
PopHeap(nsDefaultComparator<elem_type, elem_type>());
}
protected:
using base_type::Hdr;
using base_type::ShrinkCapacity;
// This method invokes elem_type's destructor on a range of elements.
// @param start The index of the first element to destroy.
// @param count The number of elements to destroy.
void DestructRange(index_type start, size_type count) {
elem_type *iter = Elements() + start, *end = iter + count;
for (; iter != end; ++iter) {
elem_traits::Destruct(iter);
}
}
// This method invokes elem_type's copy-constructor on a range of elements.
// @param start The index of the first element to construct.
// @param count The number of elements to construct.
// @param values The array of elements to copy.
template<class Item>
void AssignRange(index_type start, size_type count,
const Item *values) {
elem_type *iter = Elements() + start, *end = iter + count;
for (; iter != end; ++iter, ++values) {
elem_traits::Construct(iter, *values);
}
}
// This method sifts an item down to its proper place in a binary heap
// @param index The index of the node to start sifting down from
// @param comp The Comparator used to sift down
template<class Comparator>
void SiftDown(index_type index, const Comparator& comp) {
elem_type *elem = Elements();
elem_type item = elem[index];
index_type end = Length() - 1;
while ((index * 2) < end) {
const index_type left = (index * 2) + 1;
const index_type right = (index * 2) + 2;
const index_type parent_index = index;
if (comp.LessThan(item, elem[left])) {
if (left < end &&
comp.LessThan(elem[left], elem[right])) {
index = right;
} else {
index = left;
}
} else if (left < end &&
comp.LessThan(item, elem[right])) {
index = right;
} else {
break;
}
elem[parent_index] = elem[index];
}
elem[index] = item;
}
};
//
// Convenience subtypes of nsTArray.
//
template<class E>
class FallibleTArray : public nsTArray<E, nsTArrayFallibleAllocator>
{
public:
typedef nsTArray<E, nsTArrayFallibleAllocator> base_type;
typedef typename base_type::size_type size_type;
FallibleTArray() {}
explicit FallibleTArray(size_type capacity) : base_type(capacity) {}
FallibleTArray(const FallibleTArray& other) : base_type(other) {}
};
#ifdef MOZALLOC_HAVE_XMALLOC
template<class E>
class InfallibleTArray : public nsTArray<E, nsTArrayInfallibleAllocator>
{
public:
typedef nsTArray<E, nsTArrayInfallibleAllocator> base_type;
typedef typename base_type::size_type size_type;
InfallibleTArray() {}
explicit InfallibleTArray(size_type capacity) : base_type(capacity) {}
InfallibleTArray(const InfallibleTArray& other) : base_type(other) {}
};
#endif
template<class TArrayBase, PRUint32 N>
class nsAutoArrayBase : public TArrayBase
{
public:
typedef TArrayBase base_type;
typedef typename base_type::Header Header;
typedef typename base_type::elem_type elem_type;
protected:
nsAutoArrayBase() {
Init();
}
// We need this constructor because nsAutoTArray and friends all have
// implicit copy-constructors. If we don't have this method, those
// copy-constructors will call nsAutoArrayBase's implicit copy-constructor,
// which won't call Init() and set up the auto buffer!
nsAutoArrayBase(const TArrayBase &aOther) {
Init();
AppendElements(aOther);
}
private:
// nsTArray_base casts itself as an nsAutoArrayBase in order to get a pointer
// to mAutoBuf.
template<class Allocator>
friend class nsTArray_base;
void Init() {
// We can't handle alignments greater than 8; see
// nsTArray_base::UsesAutoArrayBuffer().
PR_STATIC_ASSERT(MOZ_ALIGNOF(elem_type) <= 8);
*base_type::PtrToHdr() = reinterpret_cast<Header*>(&mAutoBuf);
base_type::Hdr()->mLength = 0;
base_type::Hdr()->mCapacity = N;
base_type::Hdr()->mIsAutoArray = 1;
NS_ASSERTION(base_type::GetAutoArrayBuffer(MOZ_ALIGNOF(elem_type)) ==
reinterpret_cast<Header*>(&mAutoBuf),
"GetAutoArrayBuffer needs to be fixed");
}
// Declare mAutoBuf aligned to the maximum of the header's alignment and
// elem_type's alignment. We need to use a union rather than
// MOZ_ALIGNED_DECL because GCC is picky about what goes into
// __attribute__((aligned(foo))).
union {
char mAutoBuf[sizeof(nsTArrayHeader) + N * sizeof(elem_type)];
mozilla::AlignedElem<PR_MAX(MOZ_ALIGNOF(Header), MOZ_ALIGNOF(elem_type))> mAlign;
};
};
template<class E, PRUint32 N, class Alloc=nsTArrayDefaultAllocator>
class nsAutoTArray : public nsAutoArrayBase<nsTArray<E, Alloc>, N>
{
typedef nsAutoArrayBase<nsTArray<E, Alloc>, N> Base;
public:
nsAutoTArray() {}
template<typename Allocator>
nsAutoTArray(const nsTArray<E, Allocator>& other) {
Base::AppendElements(other);
}
};
// Assert that nsAutoTArray doesn't have any extra padding inside.
//
// It's important that the data stored in this auto array takes up a multiple of
// 8 bytes; e.g. nsAutoTArray<PRUint32, 1> wouldn't work. Since nsAutoTArray
// contains a pointer, its size must be a multiple of alignof(void*). (This is
// because any type may be placed into an array, and there's no padding between
// elements of an array.) The compiler pads the end of the structure to
// enforce this rule.
//
// If we used nsAutoTArray<PRUint32, 1> below, this assertion would fail on a
// 64-bit system, where the compiler inserts 4 bytes of padding at the end of
// the auto array to make its size a multiple of alignof(void*) == 8 bytes.
PR_STATIC_ASSERT(sizeof(nsAutoTArray<PRUint32, 2>) ==
sizeof(void*) + sizeof(nsTArrayHeader) + sizeof(PRUint32) * 2);
template<class E, PRUint32 N>
class AutoFallibleTArray : public nsAutoArrayBase<FallibleTArray<E>, N>
{
typedef nsAutoArrayBase<FallibleTArray<E>, N> Base;
public:
AutoFallibleTArray() {}
template<typename Allocator>
AutoFallibleTArray(const nsTArray<E, Allocator>& other) {
Base::AppendElements(other);
}
};
#if defined(MOZALLOC_HAVE_XMALLOC)
template<class E, PRUint32 N>
class AutoInfallibleTArray : public nsAutoArrayBase<InfallibleTArray<E>, N>
{
typedef nsAutoArrayBase<InfallibleTArray<E>, N> Base;
public:
AutoInfallibleTArray() {}
template<typename Allocator>
AutoInfallibleTArray(const nsTArray<E, Allocator>& other) {
Base::AppendElements(other);
}
};
#endif
// specializations for N = 0. this makes the inheritance model easier for
// templated users of nsAutoTArray.
template<class E>
class nsAutoTArray<E, 0, nsTArrayDefaultAllocator> :
public nsAutoArrayBase< nsTArray<E, nsTArrayDefaultAllocator>, 0>
{
public:
nsAutoTArray() {}
};
template<class E>
class AutoFallibleTArray<E, 0> :
public nsAutoArrayBase< FallibleTArray<E>, 0>
{
public:
AutoFallibleTArray() {}
};
#if defined(MOZALLOC_HAVE_XMALLOC)
template<class E>
class AutoInfallibleTArray<E, 0> :
public nsAutoArrayBase< InfallibleTArray<E>, 0>
{
public:
AutoInfallibleTArray() {}
};
#endif
// Definitions of nsTArray methods
#include "nsTArray-inl.h"
#endif // nsTArray_h__
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