274 lines
8.6 KiB
C++
274 lines
8.6 KiB
C++
// © 2016 and later: Unicode, Inc. and others.
|
|
// License & terms of use: http://www.unicode.org/copyright.html
|
|
/*
|
|
*******************************************************************************
|
|
*
|
|
* Copyright (C) 2003-2013, International Business Machines
|
|
* Corporation and others. All Rights Reserved.
|
|
*
|
|
*******************************************************************************
|
|
* file name: uarrsort.c
|
|
* encoding: UTF-8
|
|
* tab size: 8 (not used)
|
|
* indentation:4
|
|
*
|
|
* created on: 2003aug04
|
|
* created by: Markus W. Scherer
|
|
*
|
|
* Internal function for sorting arrays.
|
|
*/
|
|
|
|
#include <cstddef>
|
|
|
|
#include "unicode/utypes.h"
|
|
#include "cmemory.h"
|
|
#include "uarrsort.h"
|
|
|
|
enum {
|
|
/**
|
|
* "from Knuth"
|
|
*
|
|
* A binary search over 8 items performs 4 comparisons:
|
|
* log2(8)=3 to subdivide, +1 to check for equality.
|
|
* A linear search over 8 items on average also performs 4 comparisons.
|
|
*/
|
|
MIN_QSORT=9,
|
|
STACK_ITEM_SIZE=200
|
|
};
|
|
|
|
static constexpr int32_t sizeInMaxAlignTs(int32_t sizeInBytes) {
|
|
return (sizeInBytes + sizeof(std::max_align_t) - 1) / sizeof(std::max_align_t);
|
|
}
|
|
|
|
/* UComparator convenience implementations ---------------------------------- */
|
|
|
|
U_CAPI int32_t U_EXPORT2
|
|
uprv_uint16Comparator(const void *context, const void *left, const void *right) {
|
|
(void)context;
|
|
return (int32_t)*(const uint16_t *)left - (int32_t)*(const uint16_t *)right;
|
|
}
|
|
|
|
U_CAPI int32_t U_EXPORT2
|
|
uprv_int32Comparator(const void *context, const void *left, const void *right) {
|
|
(void)context;
|
|
return *(const int32_t *)left - *(const int32_t *)right;
|
|
}
|
|
|
|
U_CAPI int32_t U_EXPORT2
|
|
uprv_uint32Comparator(const void *context, const void *left, const void *right) {
|
|
(void)context;
|
|
uint32_t l=*(const uint32_t *)left, r=*(const uint32_t *)right;
|
|
|
|
/* compare directly because (l-r) would overflow the int32_t result */
|
|
if(l<r) {
|
|
return -1;
|
|
} else if(l==r) {
|
|
return 0;
|
|
} else /* l>r */ {
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
/* Insertion sort using binary search --------------------------------------- */
|
|
|
|
U_CAPI int32_t U_EXPORT2
|
|
uprv_stableBinarySearch(char *array, int32_t limit, void *item, int32_t itemSize,
|
|
UComparator *cmp, const void *context) {
|
|
int32_t start=0;
|
|
UBool found=FALSE;
|
|
|
|
/* Binary search until we get down to a tiny sub-array. */
|
|
while((limit-start)>=MIN_QSORT) {
|
|
int32_t i=(start+limit)/2;
|
|
int32_t diff=cmp(context, item, array+i*itemSize);
|
|
if(diff==0) {
|
|
/*
|
|
* Found the item. We look for the *last* occurrence of such
|
|
* an item, for stable sorting.
|
|
* If we knew that there will be only few equal items,
|
|
* we could break now and enter the linear search.
|
|
* However, if there are many equal items, then it should be
|
|
* faster to continue with the binary search.
|
|
* It seems likely that we either have all unique items
|
|
* (where found will never become TRUE in the insertion sort)
|
|
* or potentially many duplicates.
|
|
*/
|
|
found=TRUE;
|
|
start=i+1;
|
|
} else if(diff<0) {
|
|
limit=i;
|
|
} else {
|
|
start=i;
|
|
}
|
|
}
|
|
|
|
/* Linear search over the remaining tiny sub-array. */
|
|
while(start<limit) {
|
|
int32_t diff=cmp(context, item, array+start*itemSize);
|
|
if(diff==0) {
|
|
found=TRUE;
|
|
} else if(diff<0) {
|
|
break;
|
|
}
|
|
++start;
|
|
}
|
|
return found ? (start-1) : ~start;
|
|
}
|
|
|
|
static void
|
|
doInsertionSort(char *array, int32_t length, int32_t itemSize,
|
|
UComparator *cmp, const void *context, void *pv) {
|
|
int32_t j;
|
|
|
|
for(j=1; j<length; ++j) {
|
|
char *item=array+j*itemSize;
|
|
int32_t insertionPoint=uprv_stableBinarySearch(array, j, item, itemSize, cmp, context);
|
|
if(insertionPoint<0) {
|
|
insertionPoint=~insertionPoint;
|
|
} else {
|
|
++insertionPoint; /* one past the last equal item */
|
|
}
|
|
if(insertionPoint<j) {
|
|
char *dest=array+insertionPoint*itemSize;
|
|
uprv_memcpy(pv, item, itemSize); /* v=array[j] */
|
|
uprv_memmove(dest+itemSize, dest, (j-insertionPoint)*(size_t)itemSize);
|
|
uprv_memcpy(dest, pv, itemSize); /* array[insertionPoint]=v */
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
insertionSort(char *array, int32_t length, int32_t itemSize,
|
|
UComparator *cmp, const void *context, UErrorCode *pErrorCode) {
|
|
|
|
icu::MaybeStackArray<std::max_align_t, sizeInMaxAlignTs(STACK_ITEM_SIZE)> v;
|
|
if (sizeInMaxAlignTs(itemSize) > v.getCapacity() &&
|
|
v.resize(sizeInMaxAlignTs(itemSize)) == nullptr) {
|
|
*pErrorCode = U_MEMORY_ALLOCATION_ERROR;
|
|
return;
|
|
}
|
|
|
|
doInsertionSort(array, length, itemSize, cmp, context, v.getAlias());
|
|
}
|
|
|
|
/* QuickSort ---------------------------------------------------------------- */
|
|
|
|
/*
|
|
* This implementation is semi-recursive:
|
|
* It recurses for the smaller sub-array to shorten the recursion depth,
|
|
* and loops for the larger sub-array.
|
|
*
|
|
* Loosely after QuickSort algorithms in
|
|
* Niklaus Wirth
|
|
* Algorithmen und Datenstrukturen mit Modula-2
|
|
* B.G. Teubner Stuttgart
|
|
* 4. Auflage 1986
|
|
* ISBN 3-519-02260-5
|
|
*/
|
|
static void
|
|
subQuickSort(char *array, int32_t start, int32_t limit, int32_t itemSize,
|
|
UComparator *cmp, const void *context,
|
|
void *px, void *pw) {
|
|
int32_t left, right;
|
|
|
|
/* start and left are inclusive, limit and right are exclusive */
|
|
do {
|
|
if((start+MIN_QSORT)>=limit) {
|
|
doInsertionSort(array+start*itemSize, limit-start, itemSize, cmp, context, px);
|
|
break;
|
|
}
|
|
|
|
left=start;
|
|
right=limit;
|
|
|
|
/* x=array[middle] */
|
|
uprv_memcpy(px, array+(size_t)((start+limit)/2)*itemSize, itemSize);
|
|
|
|
do {
|
|
while(/* array[left]<x */
|
|
cmp(context, array+left*itemSize, px)<0
|
|
) {
|
|
++left;
|
|
}
|
|
while(/* x<array[right-1] */
|
|
cmp(context, px, array+(right-1)*itemSize)<0
|
|
) {
|
|
--right;
|
|
}
|
|
|
|
/* swap array[left] and array[right-1] via w; ++left; --right */
|
|
if(left<right) {
|
|
--right;
|
|
|
|
if(left<right) {
|
|
uprv_memcpy(pw, array+(size_t)left*itemSize, itemSize);
|
|
uprv_memcpy(array+(size_t)left*itemSize, array+(size_t)right*itemSize, itemSize);
|
|
uprv_memcpy(array+(size_t)right*itemSize, pw, itemSize);
|
|
}
|
|
|
|
++left;
|
|
}
|
|
} while(left<right);
|
|
|
|
/* sort sub-arrays */
|
|
if((right-start)<(limit-left)) {
|
|
/* sort [start..right[ */
|
|
if(start<(right-1)) {
|
|
subQuickSort(array, start, right, itemSize, cmp, context, px, pw);
|
|
}
|
|
|
|
/* sort [left..limit[ */
|
|
start=left;
|
|
} else {
|
|
/* sort [left..limit[ */
|
|
if(left<(limit-1)) {
|
|
subQuickSort(array, left, limit, itemSize, cmp, context, px, pw);
|
|
}
|
|
|
|
/* sort [start..right[ */
|
|
limit=right;
|
|
}
|
|
} while(start<(limit-1));
|
|
}
|
|
|
|
static void
|
|
quickSort(char *array, int32_t length, int32_t itemSize,
|
|
UComparator *cmp, const void *context, UErrorCode *pErrorCode) {
|
|
/* allocate two intermediate item variables (x and w) */
|
|
icu::MaybeStackArray<std::max_align_t, sizeInMaxAlignTs(STACK_ITEM_SIZE) * 2> xw;
|
|
if(sizeInMaxAlignTs(itemSize)*2 > xw.getCapacity() &&
|
|
xw.resize(sizeInMaxAlignTs(itemSize) * 2) == nullptr) {
|
|
*pErrorCode=U_MEMORY_ALLOCATION_ERROR;
|
|
return;
|
|
}
|
|
|
|
subQuickSort(array, 0, length, itemSize, cmp, context,
|
|
xw.getAlias(), xw.getAlias() + sizeInMaxAlignTs(itemSize));
|
|
}
|
|
|
|
/* uprv_sortArray() API ----------------------------------------------------- */
|
|
|
|
/*
|
|
* Check arguments, select an appropriate implementation,
|
|
* cast the array to char * so that array+i*itemSize works.
|
|
*/
|
|
U_CAPI void U_EXPORT2
|
|
uprv_sortArray(void *array, int32_t length, int32_t itemSize,
|
|
UComparator *cmp, const void *context,
|
|
UBool sortStable, UErrorCode *pErrorCode) {
|
|
if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
|
|
return;
|
|
}
|
|
if((length>0 && array==NULL) || length<0 || itemSize<=0 || cmp==NULL) {
|
|
*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
|
|
return;
|
|
}
|
|
|
|
if(length<=1) {
|
|
return;
|
|
} else if(length<MIN_QSORT || sortStable) {
|
|
insertionSort((char *)array, length, itemSize, cmp, context, pErrorCode);
|
|
} else {
|
|
quickSort((char *)array, length, itemSize, cmp, context, pErrorCode);
|
|
}
|
|
}
|