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MPWIntArray.m
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MPWIntArray.m
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//
// MPWIntArray.m
// MPWFoundation
//
// Created by Marcel Weiher on Sat Dec 27 2003.
/*
Copyright (c) 2003-2017 by Marcel Weiher. All rights reserved.
*/
//
#import "MPWIntArray.h"
#import <Foundation/Foundation.h>
#import "DebugMacros.h"
@implementation MPWIntArray
+(instancetype)array
{
return [[[self alloc] init] autorelease];
}
-(instancetype)initWithCapacity:(unsigned long)newCapacity
{
if ( self = [super init] ) {
capacity=newCapacity;
count=0;
data=malloc( (capacity+3) * sizeof(int) );
}
return self;
}
-(instancetype)init
{
return [self initWithCapacity:10];
}
-(instancetype)initFromInt:(long)start toInt:(long)stop step:(long)step
{
long theCount=(stop-start)/step + 2;
self=[self initWithCapacity:theCount];
for (int i=0;i<theCount;i++) {
data[i]=(int)(start+i*step);
}
count=theCount;
return self;
}
-(int)integerAtIndex:(unsigned)index
{
if ( index < count ) {
return data[index];
} else {
[NSException raise:@"MPWRangeException" format:@"%@ range exception: %d beyond count: %ld (capacity: %ld)",[self class],index,count,capacity];
return 0;
}
}
-(void)_growTo:(unsigned long)newCapacity
{
capacity=capacity*2+2;
capacity=MAX( capacity, newCapacity );
if ( data ) {
data=realloc( data, (capacity+3)*sizeof(int) );
} else {
data=calloc( (capacity+3), sizeof(int) );
}
}
-(void)addIntegers:(int*)intArray count:(unsigned long)numIntsToAdd
{
unsigned long newCount=count+numIntsToAdd;
if ( newCount >= capacity ) {
[self _growTo:newCount];
}
memcpy( data+count, intArray, numIntsToAdd * sizeof(int));
count=newCount;
}
-(instancetype)copy
{
MPWIntArray *copy=[[[self class] alloc] initWithCapacity:capacity];
[copy addIntegers:data count:count];
return copy;
}
-(void)addInteger:(int)anInt
{
unsigned long newCount=count+1;
if ( newCount >= capacity ) {
[self _growTo:newCount];
}
data[count]=anInt;
count=newCount;
}
-(void)writeInteger:(long)anInt
{
unsigned long newCount=count+1;
if ( newCount >= capacity ) {
[self _growTo:newCount];
}
data[count]=(int)anInt;
count=newCount;
}
-(void)addObject:anObject
{
[self addInteger:[anObject intValue]];
}
-(void)writeObject:anObject
{
[self addInteger:[anObject intValue]];
}
-(void)removeLastObject
{
if ( count) {
count--;
}
}
-(void)replaceIntegerAtIndex:(unsigned long)anIndex withInteger:(int)anInt
{
if ( anIndex < count ) {
data[anIndex]=anInt;
} else {
[NSException raise:@"MPWRangeException" format:@"%@ range exception: %ld beyond count: %ld (capacity: %ld)",[self class],anIndex,count,capacity];
}
}
-(void)replaceObjectAtIndex:(unsigned)anIndex withObject:anObject
{
[self replaceIntegerAtIndex:anIndex withInteger:[anObject intValue]];
}
-(void)dealloc
{
if ( data ) {
free(data);
}
[super dealloc];
}
-(NSUInteger)count
{
return count;
}
-(void)reset
{
count=0;
}
-(int*)integers
{
return data;
}
-(int)lastInteger
{
return data[count-1];
}
-description
{
if ( [self count] ) {
NSMutableString *description=[NSMutableString stringWithFormat:@"( %d",[self integerAtIndex:0]];
for (int i=1;i<[self count];i++) {
[description appendFormat:@", %d",[self integerAtIndex:i]];
}
[description appendString:@")"];
return description;
} else {
return @"( )";
}
}
static void doSort(int a[], int left, int right);
static void dualPivotQuicksort(int a[], int left, int right) {
// Compute indices of five evenly spaced elements
int sixth = (right - left + 1) / 6;
int e1 = left + sixth;
int e5 = right - sixth;
int e3 = (left + right) / 2; // The midpoint
int e4 = e3 + sixth;
int e2 = e3 - sixth;
// Sort these elements using a 5-element sorting network
int ae1 = a[e1], ae2 = a[e2], ae3 = a[e3], ae4 = a[e4], ae5 = a[e5];
if (ae1 > ae2) { int t = ae1; ae1 = ae2; ae2 = t; }
if (ae4 > ae5) { int t = ae4; ae4 = ae5; ae5 = t; }
if (ae1 > ae3) { int t = ae1; ae1 = ae3; ae3 = t; }
if (ae2 > ae3) { int t = ae2; ae2 = ae3; ae3 = t; }
if (ae1 > ae4) { int t = ae1; ae1 = ae4; ae4 = t; }
if (ae3 > ae4) { int t = ae3; ae3 = ae4; ae4 = t; }
if (ae2 > ae5) { int t = ae2; ae2 = ae5; ae5 = t; }
if (ae2 > ae3) { int t = ae2; ae2 = ae3; ae3 = t; }
if (ae4 > ae5) { int t = ae4; ae4 = ae5; ae5 = t; }
a[e1] = ae1; a[e3] = ae3; a[e5] = ae5;
/*
* Use the second and fourth of the five sorted elements as pivots.
* These values are inexpensive approximations of the first and
* second terciles of the array. Note that pivot1 <= pivot2.
*
* The pivots are stored in local variables, and the first and
* the last of the elements to be sorted are moved to the locations
* formerly occupied by the pivots. When partitioning is complete,
* the pivots are swapped back into their final positions, and
* excluded from subsequent sorting.
*/
int pivot1 = ae2; a[e2] = a[left];
int pivot2 = ae4; a[e4] = a[right];
// Pointers
int less = left + 1; // The index of first element of center part
int great = right - 1; // The index before first element of right part
BOOL pivotsDiffer = (pivot1 != pivot2);
if (pivotsDiffer) {
/*
* Partitioning:
*
* left part center part right part
* +------------------------------------------------------------+
* | < pivot1 | pivot1 <= && <= pivot2 | ? | > pivot2 |
* +------------------------------------------------------------+
* ^ ^ ^
* | | |
* less k great
*
* Invariants:
*
* all in (left, less) < pivot1
* pivot1 <= all in [less, k) <= pivot2
* all in (great, right) > pivot2
*
* Pointer k is the first index of ?-part
*/
outer:
for (int k = less; k <= great; k++) {
int ak = a[k];
if (ak < pivot1) { // Move a[k] to left part
if (k != less) {
a[k] = a[less];
a[less] = ak;
}
less++;
} else if (ak > pivot2) { // Move a[k] to right part
while (a[great] > pivot2) {
if (great-- == k) {
goto outer;
}
}
if (a[great] < pivot1) {
a[k] = a[less];
a[less++] = a[great];
a[great--] = ak;
} else { // pivot1 <= a[great] <= pivot2
a[k] = a[great];
a[great--] = ak;
}
}
}
} else { // Pivots are equal
/*
* Partition degenerates to the traditional 3-way,
* or "Dutch National Flag", partition:
*
* left part center part right part
* +----------------------------------------------+
* | < pivot | == pivot | ? | > pivot |
* +----------------------------------------------+
* ^ ^ ^
* | | |
* less k great
*
* Invariants:
*
* all in (left, less) < pivot
* all in [less, k) == pivot
* all in (great, right) > pivot
*
* Pointer k is the first index of ?-part
*/
for (int k = less; k <= great; k++) {
int ak = a[k];
if (ak == pivot1) {
continue;
}
if (ak < pivot1) { // Move a[k] to left part
if (k != less) {
a[k] = a[less];
a[less] = ak;
}
less++;
} else { // (a[k] > pivot1) - Move a[k] to right part
/*
* We know that pivot1 == a[e3] == pivot2. Thus, we know
* that great will still be >= k when the following loop
* terminates, even though we don't test for it explicitly.
* In other words, a[e3] acts as a sentinel for great.
*/
while (a[great] > pivot1) {
great--;
}
if (a[great] < pivot1) {
a[k] = a[less];
a[less++] = a[great];
a[great--] = ak;
} else { // a[great] == pivot1
a[k] = pivot1;
a[great--] = ak;
}
}
}
}
// Swap pivots into their final positions
a[left] = a[less - 1]; a[less - 1] = pivot1;
a[right] = a[great + 1]; a[great + 1] = pivot2;
// Sort left and right parts recursively, excluding known pivot values
doSort(a, left, less - 2);
doSort(a, great + 2, right);
/*
* If pivot1 == pivot2, all elements from center
* part are equal and, therefore, already sorted
*/
if (!pivotsDiffer) {
return;
}
/*
* If center part is too large (comprises > 2/3 of the array),
* swap internal pivot values to ends
*/
if (less < e1 && great > e5) {
while (a[less] == pivot1) {
less++;
}
while (a[great] == pivot2) {
great--;
}
/*
* Partitioning:
*
* left part center part right part
* +----------------------------------------------------------+
* | == pivot1 | pivot1 < && < pivot2 | ? | == pivot2 |
* +----------------------------------------------------------+
* ^ ^ ^
* | | |
* less k great
*
* Invariants:
*
* all in (*, less) == pivot1
* pivot1 < all in [less, k) < pivot2
* all in (great, *) == pivot2
*
* Pointer k is the first index of ?-part
*/
outer1:
for (int k = less; k <= great; k++) {
int ak = a[k];
if (ak == pivot2) { // Move a[k] to right part
while (a[great] == pivot2) {
if (great-- == k) {
goto outer1;
}
}
if (a[great] == pivot1) {
a[k] = a[less];
a[less++] = pivot1;
} else { // pivot1 < a[great] < pivot2
a[k] = a[great];
}
a[great--] = pivot2;
} else if (ak == pivot1) { // Move a[k] to left part
a[k] = a[less];
a[less++] = pivot1;
}
}
}
// Sort center part recursively, excluding known pivot values
doSort(a, less, great);
}
#define INSERTION_SORT_THRESHOLD 10
static void doSort(int a[], int left, int right) {
// Use insertion sort on tiny arrays
if (right - left + 1 < INSERTION_SORT_THRESHOLD) {
for (int i = left + 1; i <= right; i++) {
int ai = a[i];
int j;
for (j = i - 1; j >= left && ai < a[j]; j--) {
a[j + 1] = a[j];
}
a[j + 1] = ai;
}
} else { // Use Dual-Pivot Quicksort on large arrays
dualPivotQuicksort(a, left, right);
}
}
-(void)dualPivotQuicksort
{
doSort(data, 0, (int)(count -1));
}
static int compareIntegerPointers(const void *va , const void *vb )
{
const int *a=va,*b=vb;
return *a - *b;
}
-(void)systemQuicksortFunction
{
qsort(data, count, sizeof(int), compareIntegerPointers);
}
-(void)sort
{
[self systemQuicksortFunction];
}
-(MPWIntArray *)sorted
{
MPWIntArray *sorted=[[self copy] autorelease];
[sorted sort];
return sorted;
}
-(void)do:(void(^)(int))block
{
for (int i=0;i<count;i++) {
block(data[i]);
}
}
-(instancetype)select:(BOOL(^)(int))block
{
MPWIntArray *result=[MPWIntArray array];
for (int i=0;i<count;i++) {
if ( block(data[i]) ) {
[result addInteger:data[i]];
}
}
return result;
}
@end
@implementation MPWIntArray(testing)
+(void)testArrayAccess
{
id array=[self array];
INTEXPECT( [array count], 0 ,@"count of empty array");
[array addInteger:42];
INTEXPECT( [array count],1 ,@"count after adding 1 element");
INTEXPECT( [array integerAtIndex:0],42 ,@"value of element I put");
[array addObject:@"50"];
INTEXPECT( [array count],2 ,@"count after adding 2nd element");
INTEXPECT( [array integerAtIndex:1],50 ,@"value of 2nd element I put");
}
+testSelectors
{
return [NSArray arrayWithObjects:
@"testArrayAccess",
nil];
}
@end