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| -rw-r--r-- | src/libs/xpcom18a4/xpcom/ds/nsDeque.cpp | 627 |
1 files changed, 627 insertions, 0 deletions
diff --git a/src/libs/xpcom18a4/xpcom/ds/nsDeque.cpp b/src/libs/xpcom18a4/xpcom/ds/nsDeque.cpp new file mode 100644 index 00000000..d94568bc --- /dev/null +++ b/src/libs/xpcom18a4/xpcom/ds/nsDeque.cpp @@ -0,0 +1,627 @@ +/* -*- 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); +} |