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gecko-dev/xpcom/ds/nsValueArray.cpp

300 строки
9.4 KiB
C++
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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* 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 nsValueArray.h/nsValueArray.cpp code, released
* Dec 28, 2001.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 2001 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
* Garrett Arch Blythe, 20-December-2001
*
* Alternatively, the contents of this file may be used under the
* terms of the GNU Public License (the "GPL"), in which case the
* provisions of the GPL are applicable instead of those above.
* If you wish to allow use of your version of this file only
* under the terms of the GPL and not to allow others to use your
* version of this file under the MPL, indicate your decision by
* deleting the provisions above and replace them with the notice
* and other provisions required by the GPL. If you do not delete
* the provisions above, a recipient may use your version of this
* file under either the MPL or the GPL.
*/
//
// nsValueArray.cpp
//
// Implement an array class to store unsigned integer values.
// The maximum value must be known up front. Once known, the
// smallest memory representation will be attempted; i.e. if the
// maximum value was 1275, then 2 bytes (uint16) would represent each value
// in the array instead of 4 bytes (uint32).
//
#include "nsValueArray.h"
#include "nsCRT.h"
#include "prmem.h"
#include "prbit.h"
#define NSVALUEARRAY_LINEAR_GROWBY 8
#define NSVALUEARRAY_LINEAR_THRESHOLD 128
nsValueArray::nsValueArray(nsValueArrayValue aMaxValue, nsValueArrayCount aInitialCapacity) {
mCount = 0;
mCapacity = 0;
mValueArray = nsnull;
PRUint8 test8 = (PRUint8)aMaxValue;
PRUint16 test16 = (PRUint16)aMaxValue;
PRUint32 test32 = (PRUint32)aMaxValue;
if ((nsValueArrayValue)test8 == aMaxValue) {
mBytesPerValue = sizeof(test8);
}
else if ((nsValueArrayValue)test16 == aMaxValue) {
mBytesPerValue = sizeof(test16);
}
else if ((nsValueArrayValue)test32 == aMaxValue) {
mBytesPerValue = sizeof(test32);
}
else {
NS_ASSERTION(0, "not supported yet, add it yourself...");
mBytesPerValue = 0;
}
if (aInitialCapacity) {
mValueArray = (PRUint8*)PR_Malloc(aInitialCapacity * mBytesPerValue);
if (nsnull != mValueArray) {
mCapacity = aInitialCapacity;
}
}
}
nsValueArray::~nsValueArray() {
if (nsnull != mValueArray) {
PR_Free(mValueArray);
mValueArray = nsnull;
}
}
//
// Copy it.
//
nsValueArray& nsValueArray::operator=(const nsValueArray& aOther) {
//
// Free off what you know if not enough space, or units differ.
//
if ((mBytesPerValue != aOther.mBytesPerValue || mCapacity < aOther.mCount) && nsnull != mValueArray) {
PR_Free(mValueArray);
mValueArray = nsnull;
mCount = mCapacity = 0;
}
//
// Copy some attribs.
//
mBytesPerValue = aOther.mBytesPerValue;
mCount = aOther.mCount;
//
// Anything to do?
//
if (0 != mCount) {
//
// May need to allocate our buffer.
//
if (0 == mCapacity) {
mValueArray = (PRUint8*)PR_Malloc(mCount * mBytesPerValue);
mCapacity = mCount;
}
NS_ASSERTION(nsnull != mValueArray, "loss of value array assignment and original data.");
if (nsnull != mValueArray) {
memcpy(mValueArray, aOther.mValueArray, mCount * mBytesPerValue);
}
else {
mCount = mCapacity = 0;
}
}
return *this;
}
//
// Insert a value into the array.
// No validity checking other than index is done.
//
PRBool nsValueArray::InsertValueAt(nsValueArrayValue aValue, nsValueArrayIndex aIndex) {
PRBool retval = PR_FALSE;
nsValueArrayCount count = Count();
if (aIndex <= count) {
//
// If we're at capacity, then we'll need to grow a little.
//
if (Capacity() == count) {
PRUint8* reallocRes = nsnull;
nsValueArrayCount growBy = NSVALUEARRAY_LINEAR_GROWBY;
//
// Up to a particular limit we grow in small increments.
// Otherwise, grow exponentially.
//
if (count >= NSVALUEARRAY_LINEAR_THRESHOLD) {
growBy = PR_BIT(PR_CeilingLog2(count + 1)) - count;
}
if (nsnull == mValueArray) {
reallocRes = (PRUint8*)PR_Malloc((count + growBy) * mBytesPerValue);
}
else {
reallocRes = (PRUint8*)PR_Realloc(mValueArray, (count + growBy) * mBytesPerValue);
}
if (nsnull != reallocRes) {
mValueArray = reallocRes;
mCapacity += growBy;
}
}
//
// Only if we are below capacity do we continue.
//
if (Capacity() > count) {
//
// All those at and beyond the insertion point need to move.
//
if (aIndex < count) {
memmove(&mValueArray[(aIndex + 1) * mBytesPerValue], &mValueArray[aIndex * mBytesPerValue], (count - aIndex) * mBytesPerValue);
}
//
// Do the assignment.
//
switch (mBytesPerValue) {
case sizeof(PRUint8):
*((PRUint8*)&mValueArray[aIndex * mBytesPerValue]) = (PRUint8)aValue;
NS_ASSERTION(*((PRUint8*)&mValueArray[aIndex * mBytesPerValue]) == aValue, "Lossy value array detected. Report a higher maximum upon construction!");
break;
case sizeof(PRUint16):
*((PRUint16*)&mValueArray[aIndex * mBytesPerValue]) = (PRUint16)aValue;
NS_ASSERTION(*((PRUint16*)&mValueArray[aIndex * mBytesPerValue]) == aValue, "Lossy value array detected. Report a higher maximum upon construction!");
break;
case sizeof(PRUint32):
*((PRUint32*)&mValueArray[aIndex * mBytesPerValue]) = (PRUint32)aValue;
NS_ASSERTION(*((PRUint32*)&mValueArray[aIndex * mBytesPerValue]) == aValue, "Lossy value array detected. Report a higher maximum upon construction!");
break;
default:
NS_ASSERTION(0, "surely you've been warned prior to this!");
break;
}
//
// Up the count by 1.
//
mCount++;
}
}
return retval;
}
//
// Remove the index from the value array.
// The array does not shrink until Compact() is invoked.
//
PRBool nsValueArray::RemoveValueAt(nsValueArrayIndex aIndex) {
PRBool retval = PR_FALSE;
nsValueArrayCount count = Count();
if (aIndex < count) {
//
// Move memory around if appropriate.
//
if (aIndex != (count - 1)) {
memmove(&mValueArray[aIndex * mBytesPerValue], &mValueArray[(aIndex + 1) * mBytesPerValue], (count - aIndex - 1) * mBytesPerValue);
}
//
// Update our count.
//
mCount--;
}
return retval;
}
//
// Shrink as much as possible.
//
void nsValueArray::Compact() {
nsValueArrayCount count = Count();
if (Capacity() != count)
{
if (0 == count) {
PR_Free(mValueArray);
mValueArray = nsnull;
mCapacity = 0;
}
else {
PRUint8* reallocRes = (PRUint8*)PR_Realloc(mValueArray, count * mBytesPerValue);
if (nsnull != reallocRes) {
mValueArray = reallocRes;
mCapacity = count;
}
}
}
}
//
// Return the value at the index.
//
nsValueArrayValue nsValueArray::ValueAt(nsValueArrayIndex aIndex) const {
nsValueArrayValue retval = NSVALUEARRAY_INVALID;
if (aIndex < Count()) {
switch (mBytesPerValue) {
case sizeof(PRUint8):
retval = (nsValueArrayIndex)*((PRUint8*)&mValueArray[aIndex * mBytesPerValue]);
break;
case sizeof(PRUint16):
retval = (nsValueArrayIndex)*((PRUint16*)&mValueArray[aIndex * mBytesPerValue]);
break;
case sizeof(PRUint32):
retval = (nsValueArrayIndex)*((PRUint32*)&mValueArray[aIndex * mBytesPerValue]);
break;
default:
NS_ASSERTION(0, "unexpected for sure.");
break;
}
}
return retval;
}
//
// Return the first encountered index of the value.
//
nsValueArrayIndex nsValueArray::IndexOf(nsValueArrayValue aPossibleValue) const {
nsValueArrayIndex retval = NSVALUEARRAY_INVALID;
nsValueArrayIndex traverse;
for (traverse = 0; traverse < Count(); traverse++) {
if (aPossibleValue == ValueAt(traverse)) {
retval = traverse;
break;
}
}
return retval;
}
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