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author | vvvv <vvvv@yandex-team.ru> | 2022-03-03 23:09:11 +0300 |
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committer | vvvv <vvvv@yandex-team.ru> | 2022-03-03 23:09:11 +0300 |
commit | 8dbdbab054b6eb352cfffdad09991052008062fc (patch) | |
tree | 71befed92d327f2cc409bff4986ec510d0530d92 /contrib/libs/icu/common/uarrsort.cpp | |
parent | ed3f4e21f3a3837059607ec2606e1dc910269ac0 (diff) | |
download | ydb-8dbdbab054b6eb352cfffdad09991052008062fc.tar.gz |
YQL-13710 try to switch to new shiny PG
ref:2bed0445c8e8bd6c575883632adf19445f0a72a7
Diffstat (limited to 'contrib/libs/icu/common/uarrsort.cpp')
-rw-r--r-- | contrib/libs/icu/common/uarrsort.cpp | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/contrib/libs/icu/common/uarrsort.cpp b/contrib/libs/icu/common/uarrsort.cpp new file mode 100644 index 0000000000..c17dbb2e2b --- /dev/null +++ b/contrib/libs/icu/common/uarrsort.cpp @@ -0,0 +1,274 @@ +// © 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); + } +} |