зеркало из https://github.com/mozilla/gecko-dev.git
594 строки
15 KiB
C++
594 строки
15 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "nsDeque.h"
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#include "nsTraceRefcnt.h"
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#include <string.h>
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#ifdef DEBUG_rickg
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#include <stdio.h>
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#endif
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/**
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* 07/02/2001 09:17p 509,104 clangref.pdf from openwatcom's site
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* Watcom C Language Reference Edition 11.0c
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* page 118 of 297
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*
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* The % symbol yields the remainder from the division of the first operand
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* by the second operand. The operands of % must have integral type.
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*
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* When both operands of % are positive, the result is a positive value
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* smaller than the second operand. When one or both operands is negative,
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* whether the result is positive or negative is implementation-defined.
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*
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*/
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/* Ok, so first of all, C is underspecified. joy.
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* The following functions do not provide a correct implementation of modulus
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* They provide functionality for x>-y.
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* There are risks of 2*y being greater than max int, which is part of the
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* reason no multiplication is used and other operations are avoided.
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*
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* modasgn
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* @param x variable
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* @param y expression
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* approximately equivalent to x %= y
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*
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* modulus
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* @param x expression
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* @param y expression
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* approximately equivalent to x % y
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*/
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#define modasgn(x,y) if (x<0) x+=y; x%=y
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#define modulus(x,y) ((x<0)?(x+y)%(y):(x)%(y))
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/**
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* Standard constructor
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* @param deallocator, called by Erase and ~nsDeque
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*/
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nsDeque::nsDeque(nsDequeFunctor* aDeallocator) {
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MOZ_COUNT_CTOR(nsDeque);
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mDeallocator=aDeallocator;
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mOrigin=mSize=0;
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mData=mBuffer; // don't allocate space until you must
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mCapacity=sizeof(mBuffer)/sizeof(mBuffer[0]);
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memset(mData, 0, mCapacity*sizeof(mBuffer[0]));
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}
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/**
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* Destructor
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*/
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nsDeque::~nsDeque() {
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MOZ_COUNT_DTOR(nsDeque);
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#ifdef DEBUG_rickg
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char buffer[30];
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printf("Capacity: %i\n", mCapacity);
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static int mCaps[15] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
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switch(mCapacity) {
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case 4: mCaps[0]++; break;
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case 8: mCaps[1]++; break;
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case 16: mCaps[2]++; break;
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case 32: mCaps[3]++; break;
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case 64: mCaps[4]++; break;
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case 128: mCaps[5]++; break;
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case 256: mCaps[6]++; break;
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case 512: mCaps[7]++; break;
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case 1024: mCaps[8]++; break;
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case 2048: mCaps[9]++; break;
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case 4096: mCaps[10]++; break;
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default:
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break;
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}
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#endif
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Erase();
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if (mData && (mData!=mBuffer)) {
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free(mData);
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}
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mData=0;
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SetDeallocator(0);
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}
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/**
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* Set the functor to be called by Erase()
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* The deque owns the functor.
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*
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* @param aDeallocator functor object for use by Erase()
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*/
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void nsDeque::SetDeallocator(nsDequeFunctor* aDeallocator){
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delete mDeallocator;
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mDeallocator=aDeallocator;
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}
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/**
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* Remove all items from container without destroying them.
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*/
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void nsDeque::Empty() {
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if (mSize && mData) {
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memset(mData, 0, mCapacity*sizeof(mData));
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}
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mSize=0;
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mOrigin=0;
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}
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/**
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* Remove and delete all items from container
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*/
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void nsDeque::Erase() {
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if (mDeallocator && mSize) {
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ForEach(*mDeallocator);
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}
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Empty();
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}
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/**
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* This method quadruples the size of the deque
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* Elements in the deque are resequenced so that elements
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* in the deque are stored sequentially
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*
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* @return whether growing succeeded
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*/
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bool nsDeque::GrowCapacity() {
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int32_t theNewSize=mCapacity<<2;
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NS_ASSERTION(theNewSize>mCapacity, "Overflow");
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if (theNewSize<=mCapacity)
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return false;
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void** temp=(void**)malloc(theNewSize * sizeof(void*));
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if (!temp)
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return false;
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//Here's the interesting part: You can't just move the elements
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//directly (in situ) from the old buffer to the new one.
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//Since capacity has changed, the old origin doesn't make
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//sense anymore. It's better to resequence the elements now.
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memcpy(temp, mData + mOrigin, sizeof(void*) * (mCapacity - mOrigin));
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memcpy(temp + (mCapacity - mOrigin), mData, sizeof(void*) * mOrigin);
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if (mData != mBuffer) {
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free(mData);
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}
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mCapacity=theNewSize;
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mOrigin=0; //now realign the origin...
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mData=temp;
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return true;
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}
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/**
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* This method adds an item to the end of the deque.
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* This operation has the potential to cause the
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* underlying buffer to resize.
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*
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* @param aItem: new item to be added to deque
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*/
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bool nsDeque::Push(void* aItem, const fallible_t&) {
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if (mSize==mCapacity && !GrowCapacity()) {
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return false;
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}
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mData[modulus(mOrigin + mSize, mCapacity)]=aItem;
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mSize++;
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return true;
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}
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/**
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* This method adds an item to the front of the deque.
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* This operation has the potential to cause the
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* underlying buffer to resize.
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*
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* --Commments for GrowCapacity() case
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* We've grown and shifted which means that the old
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* final element in the deque is now the first element
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* in the deque. This is temporary.
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* We haven't inserted the new element at the front.
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*
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* To continue with the idea of having the front at zero
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* after a grow, we move the old final item (which through
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* the voodoo of mOrigin-- is now the first) to its final
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* position which is conveniently the old length.
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*
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* Note that this case only happens when the deque is full.
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* [And that pieces of this magic only work if the deque is full.]
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* picture:
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* [ABCDEFGH] @[mOrigin:3]:D.
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* Task: PushFront("Z")
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* shift mOrigin so, @[mOrigin:2]:C
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* stretch and rearrange: (mOrigin:0)
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* [CDEFGHAB ________ ________ ________]
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* copy: (The second C is currently out of bounds)
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* [CDEFGHAB C_______ ________ ________]
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* later we will insert Z:
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* [ZDEFGHAB C_______ ________ ________]
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* and increment size: 9. (C is no longer out of bounds)
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* --
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* @param aItem: new item to be added to deque
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*/
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bool nsDeque::PushFront(void* aItem, const fallible_t&) {
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mOrigin--;
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modasgn(mOrigin,mCapacity);
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if (mSize==mCapacity) {
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if (!GrowCapacity()) {
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return false;
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}
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/* Comments explaining this are above*/
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mData[mSize]=mData[mOrigin];
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}
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mData[mOrigin]=aItem;
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mSize++;
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return true;
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}
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/**
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* Remove and return the last item in the container.
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*
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* @return ptr to last item in container
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*/
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void* nsDeque::Pop() {
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void* result=0;
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if (mSize>0) {
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--mSize;
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int32_t offset=modulus(mSize + mOrigin, mCapacity);
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result=mData[offset];
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mData[offset]=0;
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if (!mSize) {
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mOrigin=0;
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}
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}
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return result;
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}
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/**
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* This method gets called you want to remove and return
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* the first member in the container.
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*
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* @return last item in container
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*/
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void* nsDeque::PopFront() {
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void* result=0;
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if (mSize>0) {
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NS_ASSERTION(mOrigin < mCapacity, "Error: Bad origin");
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result=mData[mOrigin];
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mData[mOrigin++]=0; //zero it out for debugging purposes.
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mSize--;
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// Cycle around if we pop off the end
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// and reset origin if when we pop the last element
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if (mCapacity==mOrigin || !mSize) {
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mOrigin=0;
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}
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}
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return result;
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}
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/**
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* This method gets called you want to peek at the bottom
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* member without removing it.
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*
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* @return last item in container
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*/
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void* nsDeque::Peek() {
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void* result=0;
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if (mSize>0) {
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result = mData[modulus(mSize - 1 + mOrigin, mCapacity)];
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}
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return result;
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}
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/**
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* This method gets called you want to peek at the topmost
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* member without removing it.
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*
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* @return last item in container
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*/
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void* nsDeque::PeekFront() {
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void* result=0;
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if (mSize>0) {
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result=mData[mOrigin];
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}
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return result;
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}
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/**
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* Call this to retrieve the ith element from this container.
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* Keep in mind that accessing the underlying elements is
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* done in a relative fashion. Object 0 is not necessarily
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* the first element (the first element is at mOrigin).
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*
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* @param aIndex : 0 relative offset of item you want
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* @return void* or null
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*/
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void* nsDeque::ObjectAt(int32_t aIndex) const {
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void* result=0;
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if ((aIndex>=0) && (aIndex<mSize)) {
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result=mData[modulus(mOrigin + aIndex, mCapacity)];
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}
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return result;
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}
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void* nsDeque::RemoveObjectAt(int32_t aIndex) {
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if ((aIndex<0) || (aIndex>=mSize)) {
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return 0;
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}
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void* result=mData[modulus(mOrigin + aIndex, mCapacity)];
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// "Shuffle down" all elements in the array by 1, overwritting the element
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// being removed.
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for (int32_t i=aIndex; i<mSize; i++) {
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mData[modulus(mOrigin + i, mCapacity)] = mData[modulus(mOrigin + i + 1, mCapacity)];
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}
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mSize--;
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return result;
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}
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/**
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* Create and return an iterator pointing to
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* the beginning of the queue. Note that this
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* takes the circular buffer semantics into account.
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*
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* @return new deque iterator, init'ed to 1st item
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*/
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nsDequeIterator nsDeque::Begin() const{
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return nsDequeIterator(*this, 0);
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}
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/**
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* Create and return an iterator pointing to
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* the last item in the deque.
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* Note that this takes the circular buffer semantics
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* into account.
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*
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* @return new deque iterator, init'ed to the last item
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*/
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nsDequeIterator nsDeque::End() const{
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return nsDequeIterator(*this, mSize - 1);
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}
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void* nsDeque::Last() const {
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return End().GetCurrent();
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}
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/**
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* Call this method when you want to iterate all the
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* members of the container, passing a functor along
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* to call your code.
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*
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* @param aFunctor object to call for each member
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* @return *this
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*/
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void nsDeque::ForEach(nsDequeFunctor& aFunctor) const{
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for (int32_t i=0; i<mSize; i++) {
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aFunctor(ObjectAt(i));
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}
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}
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/**
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* Call this method when you want to iterate all the
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* members of the container, calling the functor you
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* passed with each member. This process will interrupt
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* if your function returns non 0 to this method.
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*
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* @param aFunctor object to call for each member
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* @return first nonzero result of aFunctor or 0.
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*/
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const void* nsDeque::FirstThat(nsDequeFunctor& aFunctor) const{
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for (int32_t i=0; i<mSize; i++) {
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void* obj=aFunctor(ObjectAt(i));
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if (obj) {
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return obj;
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}
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}
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return 0;
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}
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/******************************************************
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* Here comes the nsDequeIterator class...
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******************************************************/
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/**
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* DequeIterator is an object that knows how to iterate (forward and backward)
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* through a Deque. Normally, you don't need to do this, but there are some special
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* cases where it is pretty handy, so here you go.
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*
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* This is a standard dequeiterator constructor
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*
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* @param aQueue is the deque object to be iterated
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* @param aIndex is the starting position for your iteration
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*/
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nsDequeIterator::nsDequeIterator(const nsDeque& aQueue, int aIndex)
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: mIndex(aIndex),
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mDeque(aQueue)
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{
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}
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/**
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* Create a copy of a DequeIterator
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*
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* @param aCopy is another iterator to copy from
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*/
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nsDequeIterator::nsDequeIterator(const nsDequeIterator& aCopy)
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: mIndex(aCopy.mIndex),
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mDeque(aCopy.mDeque)
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{
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}
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/**
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* Moves iterator to first element in deque
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* @return *this
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*/
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nsDequeIterator& nsDequeIterator::First(){
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mIndex=0;
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return *this;
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}
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/**
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* Standard assignment operator for dequeiterator
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*
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* @param aCopy is an iterator to be copied from
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* @return *this
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*/
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nsDequeIterator& nsDequeIterator::operator=(const nsDequeIterator& aCopy) {
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NS_ASSERTION(&mDeque==&aCopy.mDeque,"you can't change the deque that an interator is iterating over, sorry.");
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mIndex=aCopy.mIndex;
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return *this;
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}
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/**
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* preform ! operation against to iterators to test for equivalence
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* (or lack thereof)!
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*
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* @param aIter is the object to be compared to
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* @return TRUE if NOT equal.
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*/
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bool nsDequeIterator::operator!=(nsDequeIterator& aIter) {
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return bool(!this->operator==(aIter));
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}
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/**
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* Compare two iterators for increasing order.
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*
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* @param aIter is the other iterator to be compared to
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* @return TRUE if this object points to an element before
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* the element pointed to by aIter.
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* FALSE if this and aIter are not iterating over the same deque.
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*/
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bool nsDequeIterator::operator<(nsDequeIterator& aIter) {
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return bool(((mIndex<aIter.mIndex) && (&mDeque==&aIter.mDeque)));
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}
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/**
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* Compare two iterators for equivalence.
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*
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* @param aIter is the other iterator to be compared to
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* @return TRUE if EQUAL
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*/
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bool nsDequeIterator::operator==(nsDequeIterator& aIter) {
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return bool(((mIndex==aIter.mIndex) && (&mDeque==&aIter.mDeque)));
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}
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/**
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* Compare two iterators for non strict decreasing order.
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*
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* @param aIter is the other iterator to be compared to
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* @return TRUE if this object points to the same element, or
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* an element after the element pointed to by aIter.
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* FALSE if this and aIter are not iterating over the same deque.
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*/
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bool nsDequeIterator::operator>=(nsDequeIterator& aIter) {
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return bool(((mIndex>=aIter.mIndex) && (&mDeque==&aIter.mDeque)));
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}
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/**
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* Pre-increment operator
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*
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* @return object at post-incremented index
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*/
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void* nsDequeIterator::operator++() {
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NS_ASSERTION(mIndex<mDeque.mSize,
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"You have reached the end of the Internet."\
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"You have seen everything there is to see. Please go back. Now."
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);
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#ifndef TIMELESS_LIGHTWEIGHT
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if (mIndex>=mDeque.mSize) return 0;
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#endif
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return mDeque.ObjectAt(++mIndex);
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}
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/**
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* Post-increment operator
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*
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* @param param is ignored
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* @return object at pre-incremented index
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*/
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void* nsDequeIterator::operator++(int) {
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NS_ASSERTION(mIndex<=mDeque.mSize,
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"You have already reached the end of the Internet."\
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"You have seen everything there is to see. Please go back. Now."
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);
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#ifndef TIMELESS_LIGHTWEIGHT
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if (mIndex>mDeque.mSize) return 0;
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#endif
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return mDeque.ObjectAt(mIndex++);
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}
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/**
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* Pre-decrement operator
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*
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* @return object at pre-decremented index
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*/
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void* nsDequeIterator::operator--() {
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NS_ASSERTION(mIndex>=0,
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"You have reached the beginning of the Internet."\
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"You have seen everything there is to see. Please go forward. Now."
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);
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#ifndef TIMELESS_LIGHTWEIGHT
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if (mIndex<0) return 0;
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#endif
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return mDeque.ObjectAt(--mIndex);
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}
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/**
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* Post-decrement operator
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*
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* @param param is ignored
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* @return object at post-decremented index
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*/
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void* nsDequeIterator::operator--(int) {
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NS_ASSERTION(mIndex>=0,
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"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);
|
|
}
|