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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 16:49:04 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 16:49:04 +0000
commit16f504a9dca3fe3b70568f67b7d41241ae485288 (patch)
treec60f36ada0496ba928b7161059ba5ab1ab224f9d /src/libs/xpcom18a4/xpcom/ds/nsDeque.cpp
parentInitial commit. (diff)
downloadvirtualbox-upstream.tar.xz
virtualbox-upstream.zip
Adding upstream version 7.0.6-dfsg.upstream/7.0.6-dfsgupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/libs/xpcom18a4/xpcom/ds/nsDeque.cpp')
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diff --git a/src/libs/xpcom18a4/xpcom/ds/nsDeque.cpp b/src/libs/xpcom18a4/xpcom/ds/nsDeque.cpp
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** 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 mozilla.org code.
+ *
+ * The Initial Developer of the Original Code is
+ * Netscape Communications Corporation.
+ * Portions created by the Initial Developer are Copyright (C) 1998
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of 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 ***** */
+
+#include "nsDeque.h"
+#include "nsCRT.h"
+#ifdef DEBUG_rickg
+#include <stdio.h>
+#endif
+
+/**
+ * 07/02/2001 09:17p 509,104 clangref.pdf from openwatcom's site
+ * Watcom C Language Reference Edition 11.0c
+ * page 118 of 297
+ *
+ * The % symbol yields the remainder from the division of the first operand
+ * by the second operand. The operands of % must have integral type.
+ *
+ * When both operands of % are positive, the result is a positive value
+ * smaller than the second operand. When one or both operands is negative,
+ * whether the result is positive or negative is implementation-defined.
+ *
+ */
+/* Ok, so first of all, C is underspecified. joy.
+ * The following functions do not provide a correct implementation of modulus
+ * They provide functionality for x>-y.
+ * There are risks of 2*y being greater than max int, which is part of the
+ * reason no multiplication is used and other operations are avoided.
+ *
+ * modasgn
+ * @param x variable
+ * @param y expression
+ * approximately equivalent to x %= y
+ *
+ * modulus
+ * @param x expression
+ * @param y expression
+ * approximately equivalent to x % y
+ */
+#define modasgn(x,y) if (x<0) x+=y; x%=y
+#define modulus(x,y) ((x<0)?(x+y)%(y):(x)%(y))
+
+MOZ_DECL_CTOR_COUNTER(nsDeque)
+
+/**
+ * Standard constructor
+ * @param deallocator, called by Erase and ~nsDeque
+ */
+nsDeque::nsDeque(nsDequeFunctor* aDeallocator) {
+ MOZ_COUNT_CTOR(nsDeque);
+ mDeallocator=aDeallocator;
+ mOrigin=mSize=0;
+ mData=mBuffer; // don't allocate space until you must
+ mCapacity=sizeof(mBuffer)/sizeof(mBuffer[0]);
+ memset(mData, 0, mCapacity*sizeof(mBuffer[0]));
+}
+
+/**
+ * Destructor
+ */
+nsDeque::~nsDeque() {
+ MOZ_COUNT_DTOR(nsDeque);
+
+#ifdef DEBUG_rickg
+ char buffer[30];
+ printf("Capacity: %i\n", mCapacity);
+
+ static int mCaps[15] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+ switch(mCapacity) {
+ case 4: mCaps[0]++; break;
+ case 8: mCaps[1]++; break;
+ case 16: mCaps[2]++; break;
+ case 32: mCaps[3]++; break;
+ case 64: mCaps[4]++; break;
+ case 128: mCaps[5]++; break;
+ case 256: mCaps[6]++; break;
+ case 512: mCaps[7]++; break;
+ case 1024: mCaps[8]++; break;
+ case 2048: mCaps[9]++; break;
+ case 4096: mCaps[10]++; break;
+ default:
+ break;
+ }
+#endif
+
+ Erase();
+ if (mData && (mData!=mBuffer)) {
+ delete [] mData;
+ }
+ mData=0;
+ SetDeallocator(0);
+}
+
+/**
+ * Set the functor to be called by Erase()
+ * The deque owns the functor.
+ *
+ * @param aDeallocator functor object for use by Erase()
+ */
+void nsDeque::SetDeallocator(nsDequeFunctor* aDeallocator){
+ if (mDeallocator) {
+ delete mDeallocator;
+ }
+ mDeallocator=aDeallocator;
+}
+
+/**
+ * Remove all items from container without destroying them.
+ *
+ * @return *this
+ */
+nsDeque& nsDeque::Empty() {
+ if (mSize && mData) {
+ memset(mData, 0, mCapacity*sizeof(*mData));
+ }
+ mSize=0;
+ mOrigin=0;
+ return *this;
+}
+
+/**
+ * Remove and delete all items from container
+ *
+ * @return *this
+ */
+nsDeque& nsDeque::Erase() {
+ if (mDeallocator && mSize) {
+ ForEach(*mDeallocator);
+ }
+ return Empty();
+}
+
+/**
+ * This method quadruples the size of the deque
+ * Elements in the deque are resequenced so that elements
+ * in the deque are stored sequentially
+ *
+ * If the deque actually overflows, there's very little we can do.
+ * Perhaps this function should return PRBool/nsresult indicating success/failure.
+ *
+ * @return capacity of the deque
+ * If the deque did not grow,
+ * and you knew its capacity beforehand,
+ * then this would be a way to indicate the failure.
+ */
+PRInt32 nsDeque::GrowCapacity() {
+ PRInt32 theNewSize=mCapacity<<2;
+ NS_ASSERTION(theNewSize>mCapacity, "Overflow");
+ if (theNewSize<=mCapacity)
+ return mCapacity;
+ void** temp=new void*[theNewSize];
+
+ //Here's the interesting part: You can't just move the elements
+ //directly (in situ) from the old buffer to the new one.
+ //Since capacity has changed, the old origin doesn't make
+ //sense anymore. It's better to resequence the elements now.
+
+ if (temp) {
+ PRInt32 tempi=0;
+ PRInt32 i=0;
+ PRInt32 j=0;
+ for (i=mOrigin; i<mCapacity; i++) {
+ temp[tempi++]=mData[i]; //copy the leading elements...
+ }
+ for (j=0;j<mOrigin;j++) {
+ temp[tempi++]=mData[j]; //copy the trailing elements...
+ }
+ if (mData != mBuffer) {
+ delete [] mData;
+ }
+ mCapacity=theNewSize;
+ mOrigin=0; //now realign the origin...
+ mData=temp;
+ }
+ return mCapacity;
+}
+
+/**
+ * This method adds an item to the end of the deque.
+ * This operation has the potential to cause the
+ * underlying buffer to resize.
+ *
+ * @param aItem: new item to be added to deque
+ * @return *this
+ */
+nsDeque& nsDeque::Push(void* aItem) {
+ if (mSize==mCapacity) {
+ GrowCapacity();
+ }
+ mData[modulus(mOrigin + mSize, mCapacity)]=aItem;
+ mSize++;
+ return *this;
+}
+
+/**
+ * This method adds an item to the front of the deque.
+ * This operation has the potential to cause the
+ * underlying buffer to resize.
+ *
+ * --Commments for GrowCapacity() case
+ * We've grown and shifted which means that the old
+ * final element in the deque is now the first element
+ * in the deque. This is temporary.
+ * We haven't inserted the new element at the front.
+ *
+ * To continue with the idea of having the front at zero
+ * after a grow, we move the old final item (which through
+ * the voodoo of mOrigin-- is now the first) to its final
+ * position which is conveniently the old length.
+ *
+ * Note that this case only happens when the deque is full.
+ * [And that pieces of this magic only work if the deque is full.]
+ * picture:
+ * [ABCDEFGH] @[mOrigin:3]:D.
+ * Task: PushFront("Z")
+ * shift mOrigin so, @[mOrigin:2]:C
+ * stretch and rearrange: (mOrigin:0)
+ * [CDEFGHAB ________ ________ ________]
+ * copy: (The second C is currently out of bounds)
+ * [CDEFGHAB C_______ ________ ________]
+ * later we will insert Z:
+ * [ZDEFGHAB C_______ ________ ________]
+ * and increment size: 9. (C is no longer out of bounds)
+ * --
+ * @param aItem: new item to be added to deque
+ * @return *this
+ */
+nsDeque& nsDeque::PushFront(void* aItem) {
+ mOrigin--;
+ modasgn(mOrigin,mCapacity);
+ if (mSize==mCapacity) {
+ GrowCapacity();
+ /* Comments explaining this are above*/
+ mData[mSize]=mData[mOrigin];
+ }
+ mData[mOrigin]=aItem;
+ mSize++;
+ return *this;
+}
+
+/**
+ * Remove and return the last item in the container.
+ *
+ * @return ptr to last item in container
+ */
+void* nsDeque::Pop() {
+ void* result=0;
+ if (mSize>0) {
+ --mSize;
+ PRInt32 offset=modulus(mSize + mOrigin, mCapacity);
+ result=mData[offset];
+ mData[offset]=0;
+ if (!mSize) {
+ mOrigin=0;
+ }
+ }
+ return result;
+}
+
+/**
+ * This method gets called you want to remove and return
+ * the first member in the container.
+ *
+ * @return last item in container
+ */
+void* nsDeque::PopFront() {
+ void* result=0;
+ if (mSize>0) {
+ NS_ASSERTION(mOrigin < mCapacity, "Error: Bad origin");
+ result=mData[mOrigin];
+ mData[mOrigin++]=0; //zero it out for debugging purposes.
+ mSize--;
+ // Cycle around if we pop off the end
+ // and reset origin if when we pop the last element
+ if (mCapacity==mOrigin || !mSize) {
+ mOrigin=0;
+ }
+ }
+ return result;
+}
+
+/**
+ * This method gets called you want to peek at the bottom
+ * member without removing it.
+ *
+ * @return last item in container
+ */
+void* nsDeque::Peek() {
+ void* result=0;
+ if (mSize>0) {
+ result = mData[modulus(mSize - 1 + mOrigin, mCapacity)];
+ }
+ return result;
+}
+
+/**
+ * This method gets called you want to peek at the topmost
+ * member without removing it.
+ *
+ * @return last item in container
+ */
+void* nsDeque::PeekFront() {
+ void* result=0;
+ if (mSize>0) {
+ result=mData[mOrigin];
+ }
+ return result;
+}
+
+/**
+ * Call this to retrieve the ith element from this container.
+ * Keep in mind that accessing the underlying elements is
+ * done in a relative fashion. Object 0 is not necessarily
+ * the first element (the first element is at mOrigin).
+ *
+ * @param aIndex : 0 relative offset of item you want
+ * @return void* or null
+ */
+void* nsDeque::ObjectAt(PRInt32 aIndex) const {
+ void* result=0;
+ if ((aIndex>=0) && (aIndex<mSize)) {
+ result=mData[modulus(mOrigin + aIndex, mCapacity)];
+ }
+ return result;
+}
+
+/**
+ * Create and return an iterator pointing to
+ * the beginning of the queue. Note that this
+ * takes the circular buffer semantics into account.
+ *
+ * @return new deque iterator, init'ed to 1st item
+ */
+nsDequeIterator nsDeque::Begin() const{
+ return nsDequeIterator(*this, 0);
+}
+
+/**
+ * Create and return an iterator pointing to
+ * the last item in the deque.
+ * Note that this takes the circular buffer semantics
+ * into account.
+ *
+ * @return new deque iterator, init'ed to the last item
+ */
+nsDequeIterator nsDeque::End() const{
+ return nsDequeIterator(*this, mSize - 1);
+}
+
+void* nsDeque::Last() const {
+ return End().GetCurrent();
+}
+
+/**
+ * Call this method when you want to iterate all the
+ * members of the container, passing a functor along
+ * to call your code.
+ *
+ * @param aFunctor object to call for each member
+ * @return *this
+ */
+void nsDeque::ForEach(nsDequeFunctor& aFunctor) const{
+ for (PRInt32 i=0; i<mSize; i++) {
+ aFunctor(ObjectAt(i));
+ }
+}
+
+/**
+ * Call this method when you want to iterate all the
+ * members of the container, calling the functor you
+ * passed with each member. This process will interrupt
+ * if your function returns non 0 to this method.
+ *
+ * @param aFunctor object to call for each member
+ * @return first nonzero result of aFunctor or 0.
+ */
+const void* nsDeque::FirstThat(nsDequeFunctor& aFunctor) const{
+ for (PRInt32 i=0; i<mSize; i++) {
+ void* obj=aFunctor(ObjectAt(i));
+ if (obj) {
+ return obj;
+ }
+ }
+ return 0;
+}
+
+/******************************************************
+ * Here comes the nsDequeIterator class...
+ ******************************************************/
+
+/**
+ * DequeIterator is an object that knows how to iterate (forward and backward)
+ * through a Deque. Normally, you don't need to do this, but there are some special
+ * cases where it is pretty handy, so here you go.
+ *
+ * This is a standard dequeiterator constructor
+ *
+ * @param aQueue is the deque object to be iterated
+ * @param aIndex is the starting position for your iteration
+ */
+nsDequeIterator::nsDequeIterator(const nsDeque& aQueue, int aIndex)
+: mIndex(aIndex),
+ mDeque(aQueue)
+{
+}
+
+/**
+ * Create a copy of a DequeIterator
+ *
+ * @param aCopy is another iterator to copy from
+ */
+nsDequeIterator::nsDequeIterator(const nsDequeIterator& aCopy)
+: mIndex(aCopy.mIndex),
+ mDeque(aCopy.mDeque)
+{
+}
+
+/**
+ * Moves iterator to first element in deque
+ * @return *this
+ */
+nsDequeIterator& nsDequeIterator::First(){
+ mIndex=0;
+ return *this;
+}
+
+/**
+ * Standard assignment operator for dequeiterator
+ *
+ * @param aCopy is an iterator to be copied from
+ * @return *this
+ */
+nsDequeIterator& nsDequeIterator::operator=(const nsDequeIterator& aCopy) {
+ NS_ASSERTION(&mDeque==&aCopy.mDeque,"you can't change the deque that an interator is iterating over, sorry.");
+ mIndex=aCopy.mIndex;
+ return *this;
+}
+
+/**
+ * preform ! operation against to iterators to test for equivalence
+ * (or lack thereof)!
+ *
+ * @param aIter is the object to be compared to
+ * @return TRUE if NOT equal.
+ */
+PRBool nsDequeIterator::operator!=(nsDequeIterator& aIter) {
+ return PRBool(!this->operator==(aIter));
+}
+
+/**
+ * Compare two iterators for increasing order.
+ *
+ * @param aIter is the other iterator to be compared to
+ * @return TRUE if this object points to an element before
+ * the element pointed to by aIter.
+ * FALSE if this and aIter are not iterating over the same deque.
+ */
+PRBool nsDequeIterator::operator<(nsDequeIterator& aIter) {
+ return PRBool(((mIndex<aIter.mIndex) && (&mDeque==&aIter.mDeque)));
+}
+
+/**
+ * Compare two iterators for equivalence.
+ *
+ * @param aIter is the other iterator to be compared to
+ * @return TRUE if EQUAL
+ */
+PRBool nsDequeIterator::operator==(nsDequeIterator& aIter) {
+ return PRBool(((mIndex==aIter.mIndex) && (&mDeque==&aIter.mDeque)));
+}
+
+/**
+ * Compare two iterators for non strict decreasing order.
+ *
+ * @param aIter is the other iterator to be compared to
+ * @return TRUE if this object points to the same element, or
+ * an element after the element pointed to by aIter.
+ * FALSE if this and aIter are not iterating over the same deque.
+ */
+PRBool nsDequeIterator::operator>=(nsDequeIterator& aIter) {
+ return PRBool(((mIndex>=aIter.mIndex) && (&mDeque==&aIter.mDeque)));
+}
+
+/**
+ * Pre-increment operator
+ *
+ * @return object at post-incremented index
+ */
+void* nsDequeIterator::operator++() {
+ NS_ASSERTION(mIndex<mDeque.mSize,
+ "You have reached the end of the Internet."\
+ "You have seen everything there is to see. Please go back. Now."
+ );
+#ifndef TIMELESS_LIGHTWEIGHT
+ if (mIndex>=mDeque.mSize) return 0;
+#endif
+ return mDeque.ObjectAt(++mIndex);
+}
+
+/**
+ * Post-increment operator
+ *
+ * @param param is ignored
+ * @return object at pre-incremented index
+ */
+void* nsDequeIterator::operator++(int) {
+ NS_ASSERTION(mIndex<=mDeque.mSize,
+ "You have already reached the end of the Internet."\
+ "You have seen everything there is to see. Please go back. Now."
+ );
+#ifndef TIMELESS_LIGHTWEIGHT
+ if (mIndex>mDeque.mSize) return 0;
+#endif
+ return mDeque.ObjectAt(mIndex++);
+}
+
+/**
+ * Pre-decrement operator
+ *
+ * @return object at pre-decremented index
+ */
+void* nsDequeIterator::operator--() {
+ NS_ASSERTION(mIndex>=0,
+ "You have reached the beginning of the Internet."\
+ "You have seen everything there is to see. Please go forward. Now."
+ );
+#ifndef TIMELESS_LIGHTWEIGHT
+ if (mIndex<0) return 0;
+#endif
+ return mDeque.ObjectAt(--mIndex);
+}
+
+/**
+ * Post-decrement operator
+ *
+ * @param param is ignored
+ * @return object at post-decremented index
+ */
+void* nsDequeIterator::operator--(int) {
+ NS_ASSERTION(mIndex>=0,
+ "You have already reached the beginning of the Internet."\
+ "You have seen everything there is to see. Please go forward. Now."
+ );
+#ifndef TIMELESS_LIGHTWEIGHT
+ if (mIndex<0) return 0;
+#endif
+ return mDeque.ObjectAt(mIndex--);
+}
+
+/**
+ * Dereference operator
+ * Note that the iterator floats, so you don't need to do:
+ * <code>++iter; aDeque.PopFront();</code>
+ * Unless you actually want your iterator to jump 2 spaces.
+ *
+ * Picture: [1 2I 3 4]
+ * PopFront()
+ * Picture: [2 3I 4]
+ * Note that I still happily points to object at the second index
+ *
+ * @return object at ith index
+ */
+void* nsDequeIterator::GetCurrent() {
+ NS_ASSERTION(mIndex<mDeque.mSize&&mIndex>=0,"Current is out of bounds");
+#ifndef TIMELESS_LIGHTWEIGHT
+ if (mIndex>=mDeque.mSize||mIndex<0) return 0;
+#endif
+ return mDeque.ObjectAt(mIndex);
+}
+
+/**
+ * Call this method when you want to iterate all the
+ * members of the container, passing a functor along
+ * to call your code.
+ *
+ * @param aFunctor object to call for each member
+ * @return *this
+ */
+void nsDequeIterator::ForEach(nsDequeFunctor& aFunctor) const{
+ mDeque.ForEach(aFunctor);
+}
+
+/**
+ * Call this method when you want to iterate all the
+ * members of the container, calling the functor you
+ * passed with each member. This process will interrupt
+ * if your function returns non 0 to this method.
+ *
+ * @param aFunctor object to call for each member
+ * @return first nonzero result of aFunctor or 0.
+ */
+const void* nsDequeIterator::FirstThat(nsDequeFunctor& aFunctor) const{
+ return mDeque.FirstThat(aFunctor);
+}