/src/icu/source/common/uarrsort.cpp

Source (jump to first uncovered line)
// © 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 "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
};

/* 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) {
    UAlignedMemory v[STACK_ITEM_SIZE/sizeof(UAlignedMemory)+1];
    void *pv;

    /* allocate an intermediate item variable (v) */
    if(itemSize<=STACK_ITEM_SIZE) {
        pv=v;
    } else {
        pv=uprv_malloc(itemSize);
        if(pv==NULL) {
            *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
            return;
        }
    }

    doInsertionSort(array, length, itemSize, cmp, context, pv);

    if(pv!=v) {
        uprv_free(pv);
    }
}

/* 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) {
    UAlignedMemory xw[(2*STACK_ITEM_SIZE)/sizeof(UAlignedMemory)+1];
    void *p;

    /* allocate two intermediate item variables (x and w) */
    if(itemSize<=STACK_ITEM_SIZE) {
        p=xw;
    } else {
        p=uprv_malloc(2*itemSize);
        if(p==NULL) {
            *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
            return;
        }
    }

    subQuickSort(array, 0, length, itemSize,
                 cmp, context, p, (char *)p+itemSize);

    if(p!=xw) {
        uprv_free(p);
    }
}

/* 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);
    }
}

Coverage Report

Created: 2025-07-11 06:23

Line	Count	Source (jump to first uncovered line)
1		// © 2016 and later: Unicode, Inc. and others.
2		// License & terms of use: http://www.unicode.org/copyright.html
3		/*
4		*******************************************************************************
5		*
6		* Copyright (C) 2003-2013, International Business Machines
7		* Corporation and others. All Rights Reserved.
8		*
9		*******************************************************************************
10		* file name: uarrsort.c
11		* encoding: UTF-8
12		* tab size: 8 (not used)
13		* indentation:4
14		*
15		* created on: 2003aug04
16		* created by: Markus W. Scherer
17		*
18		* Internal function for sorting arrays.
19		*/
20
21		#include "unicode/utypes.h"
22		#include "cmemory.h"
23		#include "uarrsort.h"
24
25		enum {
26		/**
27		* "from Knuth"
28		*
29		* A binary search over 8 items performs 4 comparisons:
30		* log2(8)=3 to subdivide, +1 to check for equality.
31		* A linear search over 8 items on average also performs 4 comparisons.
32		*/
33		MIN_QSORT=9,
34		STACK_ITEM_SIZE=200
35		};
36
37		/* UComparator convenience implementations ---------------------------------- */
38
39		U_CAPI int32_t U_EXPORT2
40	0	uprv_uint16Comparator(const void context, const void left, const void *right) {
41	0	(void)context;
42	0	return (int32_t)(const uint16_t )left - (int32_t)(const uint16_t )right;
43	0	}
44
45		U_CAPI int32_t U_EXPORT2
46	0	uprv_int32Comparator(const void context, const void left, const void *right) {
47	0	(void)context;
48	0	return (const int32_t )left - (const int32_t )right;
49	0	}
50
51		U_CAPI int32_t U_EXPORT2
52	0	uprv_uint32Comparator(const void context, const void left, const void *right) {
53	0	(void)context;
54	0	uint32_t l=(const uint32_t )left, r=(const uint32_t )right;
55
56		/* compare directly because (l-r) would overflow the int32_t result */
57	0	if(l<r) {
58	0	return -1;
59	0	} else if(l==r) {
60	0	return 0;
61	0	} else /* l>r */ {
62	0	return 1;
63	0	}
64	0	}
65
66		/* Insertion sort using binary search --------------------------------------- */
67
68		U_CAPI int32_t U_EXPORT2
69		uprv_stableBinarySearch(char array, int32_t limit, void item, int32_t itemSize,
70	0	UComparator cmp, const void context) {
71	0	int32_t start=0;
72	0	UBool found=FALSE;
73
74		/* Binary search until we get down to a tiny sub-array. */
75	0	while((limit-start)>=MIN_QSORT) {
76	0	int32_t i=(start+limit)/2;
77	0	int32_t diff=cmp(context, item, array+i*itemSize);
78	0	if(diff==0) {
79		/*
80		* Found the item. We look for the last occurrence of such
81		* an item, for stable sorting.
82		* If we knew that there will be only few equal items,
83		* we could break now and enter the linear search.
84		* However, if there are many equal items, then it should be
85		* faster to continue with the binary search.
86		* It seems likely that we either have all unique items
87		* (where found will never become TRUE in the insertion sort)
88		* or potentially many duplicates.
89		*/
90	0	found=TRUE;
91	0	start=i+1;
92	0	} else if(diff<0) {
93	0	limit=i;
94	0	} else {
95	0	start=i;
96	0	}
97	0	}
98
99		/* Linear search over the remaining tiny sub-array. */
100	0	while(start<limit) {
101	0	int32_t diff=cmp(context, item, array+start*itemSize);
102	0	if(diff==0) {
103	0	found=TRUE;
104	0	} else if(diff<0) {
105	0	break;
106	0	}
107	0	++start;
108	0	}
109	0	return found ? (start-1) : ~start;
110	0	}
111
112		static void
113		doInsertionSort(char *array, int32_t length, int32_t itemSize,
114	0	UComparator cmp, const void context, void *pv) {
115	0	int32_t j;
116
117	0	for(j=1; j<length; ++j) {
118	0	char item=array+jitemSize;
119	0	int32_t insertionPoint=uprv_stableBinarySearch(array, j, item, itemSize, cmp, context);
120	0	if(insertionPoint<0) {
121	0	insertionPoint=~insertionPoint;
122	0	} else {
123	0	++insertionPoint; /* one past the last equal item */
124	0	}
125	0	if(insertionPoint<j) {
126	0	char dest=array+insertionPointitemSize;
127	0	uprv_memcpy(pv, item, itemSize); /* v=array[j] */
128	0	uprv_memmove(dest+itemSize, dest, (j-insertionPoint)*(size_t)itemSize);
129	0	uprv_memcpy(dest, pv, itemSize); /* array[insertionPoint]=v */
130	0	}
131	0	}
132	0	}
133
134		static void
135		insertionSort(char *array, int32_t length, int32_t itemSize,
136	0	UComparator cmp, const void context, UErrorCode *pErrorCode) {
137	0	UAlignedMemory v[STACK_ITEM_SIZE/sizeof(UAlignedMemory)+1];
138	0	void *pv;
139
140		/* allocate an intermediate item variable (v) */
141	0	if(itemSize<=STACK_ITEM_SIZE) {
142	0	pv=v;
143	0	} else {
144	0	pv=uprv_malloc(itemSize);
145	0	if(pv==NULL) {
146	0	*pErrorCode=U_MEMORY_ALLOCATION_ERROR;
147	0	return;
148	0	}
149	0	}
150
151	0	doInsertionSort(array, length, itemSize, cmp, context, pv);
152
153	0	if(pv!=v) {
154	0	uprv_free(pv);
155	0	}
156	0	}
157
158		/* QuickSort ---------------------------------------------------------------- */
159
160		/*
161		* This implementation is semi-recursive:
162		* It recurses for the smaller sub-array to shorten the recursion depth,
163		* and loops for the larger sub-array.
164		*
165		* Loosely after QuickSort algorithms in
166		* Niklaus Wirth
167		* Algorithmen und Datenstrukturen mit Modula-2
168		* B.G. Teubner Stuttgart
169		* 4. Auflage 1986
170		* ISBN 3-519-02260-5
171		*/
172		static void
173		subQuickSort(char *array, int32_t start, int32_t limit, int32_t itemSize,
174		UComparator cmp, const void context,
175	0	void px, void pw) {
176	0	int32_t left, right;
177
178		/* start and left are inclusive, limit and right are exclusive */
179	0	do {
180	0	if((start+MIN_QSORT)>=limit) {
181	0	doInsertionSort(array+start*itemSize, limit-start, itemSize, cmp, context, px);
182	0	break;
183	0	}
184
185	0	left=start;
186	0	right=limit;
187
188		/* x=array[middle] */
189	0	uprv_memcpy(px, array+(size_t)((start+limit)/2)*itemSize, itemSize);
190
191	0	do {
192	0	while(/* array[left]<x */
193	0	cmp(context, array+left*itemSize, px)<0
194	0	) {
195	0	++left;
196	0	}
197	0	while(/* x<array[right-1] */
198	0	cmp(context, px, array+(right-1)*itemSize)<0
199	0	) {
200	0	--right;
201	0	}
202
203		/* swap array[left] and array[right-1] via w; ++left; --right */
204	0	if(left<right) {
205	0	--right;
206
207	0	if(left<right) {
208	0	uprv_memcpy(pw, array+(size_t)left*itemSize, itemSize);
209	0	uprv_memcpy(array+(size_t)leftitemSize, array+(size_t)rightitemSize, itemSize);
210	0	uprv_memcpy(array+(size_t)right*itemSize, pw, itemSize);
211	0	}
212
213	0	++left;
214	0	}
215	0	} while(left<right);
216
217		/* sort sub-arrays */
218	0	if((right-start)<(limit-left)) {
219		/* sort [start..right[ */
220	0	if(start<(right-1)) {
221	0	subQuickSort(array, start, right, itemSize, cmp, context, px, pw);
222	0	}
223
224		/* sort [left..limit[ */
225	0	start=left;
226	0	} else {
227		/* sort [left..limit[ */
228	0	if(left<(limit-1)) {
229	0	subQuickSort(array, left, limit, itemSize, cmp, context, px, pw);
230	0	}
231
232		/* sort [start..right[ */
233	0	limit=right;
234	0	}
235	0	} while(start<(limit-1));
236	0	}
237
238		static void
239		quickSort(char *array, int32_t length, int32_t itemSize,
240	0	UComparator cmp, const void context, UErrorCode *pErrorCode) {
241	0	UAlignedMemory xw[(2*STACK_ITEM_SIZE)/sizeof(UAlignedMemory)+1];
242	0	void *p;
243
244		/* allocate two intermediate item variables (x and w) */
245	0	if(itemSize<=STACK_ITEM_SIZE) {
246	0	p=xw;
247	0	} else {
248	0	p=uprv_malloc(2*itemSize);
249	0	if(p==NULL) {
250	0	*pErrorCode=U_MEMORY_ALLOCATION_ERROR;
251	0	return;
252	0	}
253	0	}
254
255	0	subQuickSort(array, 0, length, itemSize,
256	0	cmp, context, p, (char *)p+itemSize);
257
258	0	if(p!=xw) {
259	0	uprv_free(p);
260	0	}
261	0	}
262
263		/* uprv_sortArray() API ----------------------------------------------------- */
264
265		/*
266		* Check arguments, select an appropriate implementation,
267		* cast the array to char * so that array+i*itemSize works.
268		*/
269		U_CAPI void U_EXPORT2
270		uprv_sortArray(void *array, int32_t length, int32_t itemSize,
271		UComparator cmp, const void context,
272	0	UBool sortStable, UErrorCode *pErrorCode) {
273	0	if(pErrorCode==NULL \|\| U_FAILURE(*pErrorCode)) {
274	0	return;
275	0	}
276	0	if((length>0 && array==NULL) \|\| length<0 \|\| itemSize<=0 \|\| cmp==NULL) {
277	0	*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
278	0	return;
279	0	}
280
281	0	if(length<=1) {
282	0	return;
283	0	} else if(length<MIN_QSORT \|\| sortStable) {
284	0	insertionSort((char *)array, length, itemSize, cmp, context, pErrorCode);
285	0	} else {
286	0	quickSort((char *)array, length, itemSize, cmp, context, pErrorCode);
287	0	}
288	0	}