skia2/tests/SortTest.cpp
John Stiles 886a904595 Update SkTQSort to use half-open ranges.
C++ algorithms have largely standardized on a [begin, end) half-open
range, as seen in standard library containers. SkTQSort now adheres to
this model, and takes vec.begin() and vec.end() as its inputs.

To avoid confusion between inclusive and half-open ranges inside the
implementation, internal helper functions now take "left" and "count"
arguments instead of "left"/"right" or "begin"/"end". This avoids any
ambiguity.

(Although performance was not the main goal, this CL appears to
slightly improve our sorting benchmark on my machine.)

Change-Id: I5e96b6730be96cf23d001ee0915c69764b2c024a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/302579
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
2020-07-14 22:13:59 +00:00

65 lines
2.0 KiB
C++

/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "include/utils/SkRandom.h"
#include "src/core/SkTSort.h"
#include "tests/Test.h"
#include <stdlib.h>
extern "C" {
static int compare_int(const void* a, const void* b) {
return *(const int*)a - *(const int*)b;
}
}
static void rand_array(SkRandom& rand, int array[], int n) {
for (int j = 0; j < n; j++) {
array[j] = rand.nextS() & 0xFF;
}
}
static void check_sort(skiatest::Reporter* reporter, const char label[],
const int array[], const int reference[], int n) {
for (int j = 0; j < n; ++j) {
if (array[j] != reference[j]) {
ERRORF(reporter, "%sSort [%d] failed %d %d",
label, n, array[j], reference[j]);
}
}
}
DEF_TEST(Sort, reporter) {
/** An array of random numbers to be sorted. */
int randomArray[500];
/** The reference sort of the random numbers. */
int sortedArray[SK_ARRAY_COUNT(randomArray)];
/** The random numbers are copied into this array, sorted by an SkSort,
then this array is compared against the reference sort. */
int workingArray[SK_ARRAY_COUNT(randomArray)];
SkRandom rand;
for (int i = 0; i < 10000; i++) {
int count = rand.nextRangeU(1, SK_ARRAY_COUNT(randomArray));
rand_array(rand, randomArray, count);
// Use qsort as the reference sort.
memcpy(sortedArray, randomArray, sizeof(randomArray));
qsort(sortedArray, count, sizeof(sortedArray[0]), compare_int);
memcpy(workingArray, randomArray, sizeof(randomArray));
SkTHeapSort<int>(workingArray, count);
check_sort(reporter, "Heap", workingArray, sortedArray, count);
memcpy(workingArray, randomArray, sizeof(randomArray));
SkTQSort<int>(workingArray, workingArray + count);
check_sort(reporter, "Quick", workingArray, sortedArray, count);
}
}
// need tests for SkStrSearch