Refactor testqsort to test non-aligned, aligned, and non-transitive sorting

Author: aikawayataro

test/testqsort.c

@@ -14,7 +14,20 @@
 #include <SDL3/SDL_main.h>
 #include <SDL3/SDL_test.h>
 
+/* Required to test non-aligned sort */
+typedef char non_word_value[sizeof(int) * 2];
+
+typedef struct
+{
+    size_t len;
+    size_t item_size;
+    void *aligned;
+    void *unaligned;
+} test_buffer;
+
 static int a_global_var = 77;
+static int qsort_is_broken;
+static SDLTest_RandomContext rndctx;
 
 static int SDLCALL
 num_compare(const void *_a, const void *_b)
@@ -24,54 +37,238 @@ num_compare(const void *_a, const void *_b)
     return (a < b) ? -1 : ((a > b) ? 1 : 0);
 }
 
+static int SDLCALL
+num_compare_non_transitive(const void *_a, const void *_b)
+{
+    const int a = *((const int *)_a);
+    const int b = *((const int *)_b);
+    return (a < b) ? 0 : 1;
+}
+
 static int SDLCALL
 num_compare_r(void *userdata, const void *a, const void *b)
 {
     if (userdata != &a_global_var) {
         SDL_Log("Uhoh, invalid userdata during qsort!");
+        qsort_is_broken = 1;
     }
     return num_compare(a, b);
 }
 
+/* Will never return 0 */
+static int SDLCALL
+num_compare_random_any(const void *a, const void *b)
+{
+    (void)(a);
+    (void)(b);
+    return (SDLTest_Random(&rndctx) > ((Uint32)SDL_MAX_SINT32)) ? 1 : -1;
+}
+
+static int SDLCALL
+num_compare_non_word(const void *_a, const void *_b)
+{
+    const int a = (int)(((const char *)_a)[0]);
+    const int b = (int)(((const char *)_b)[0]);
+    return num_compare(&a, &b);
+}
+
+static int SDLCALL
+num_compare_non_word_r(void *userdata, const void *_a, const void *_b)
+{
+    const int a = (int)(((const char *)_a)[0]);
+    const int b = (int)(((const char *)_b)[0]);
+    return num_compare_r(userdata, &a, &b);
+}
+
+static int SDLCALL
+num_compare_non_word_non_transitive(const void *_a, const void *_b)
+{
+    const int a = (int)(((char *)_a)[0]);
+    const int b = (int)(((char *)_b)[0]);
+    return num_compare_non_transitive(&a, &b);
+}
+
 static void
-test_sort(const char *desc, int *nums, const int arraylen)
+alloc_buffer(test_buffer *buffer, size_t size, size_t len)
 {
-    static int nums_copy[1024 * 100];
-    int i;
-    int prev;
+    uintptr_t base;
 
-    SDL_assert(SDL_arraysize(nums_copy) >= arraylen);
+    SDL_memset(buffer, 0, sizeof(*buffer));
+    buffer->len = len;
+    buffer->item_size = size;
 
-    SDL_Log("test: %s arraylen=%d", desc, arraylen);
+    if (len == 0) {
+        return;
+    }
 
-    SDL_memcpy(nums_copy, nums, arraylen * sizeof (*nums));
+    buffer->aligned = SDL_malloc((len + 1) * size + sizeof(char));
+    base = (uintptr_t)(buffer->aligned);
+    /* Should be aligned */
+    SDL_assert(((base | size) & (sizeof(int) - 1)) == 0);
 
-    SDL_qsort(nums, arraylen, sizeof(nums[0]), num_compare);
-    SDL_qsort_r(nums_copy, arraylen, sizeof(nums[0]), num_compare_r, &a_global_var);
+    buffer->unaligned = (void *)(base + sizeof(char));
+}
 
-    prev = nums[0];
-    for (i = 1; i < arraylen; i++) {
+static void
+check_sort(const int *nums, const int *r_nums, int numlen) {
+    int i;
+    int prev = 0;
+
+    if (numlen > 0) {
+        prev = nums[0];
+    }
+    for (i = 1; i < numlen; i++) {
         const int val = nums[i];
-        const int val2 = nums_copy[i];
+        const int val2 = r_nums[i];
         if ((val < prev) || (val != val2)) {
             SDL_Log("sort is broken!");
-            return;
+            qsort_is_broken = 1;
+            break;
         }
         prev = val;
     }
 }
 
-int main(int argc, char *argv[])
+static void
+test_sort(const char *desc, const int *nums, int numlen)
+{
+    test_buffer buffer;
+    test_buffer buffer_r;
+
+    alloc_buffer(&buffer, sizeof(nums[0]), numlen);
+    alloc_buffer(&buffer_r, sizeof(nums[0]), numlen);
+
+    SDL_Log("test: %s bufferlen=%d", desc, (int)(buffer.len));
+
+    /* Test aligned sort */
+    if (buffer.aligned != NULL) {
+        /* memcpy with NULL is UB */
+        SDL_memcpy(buffer.aligned, nums, numlen * sizeof(nums[0]));
+        SDL_memcpy(buffer_r.aligned, nums, numlen * sizeof(nums[0]));
+    }
+    SDL_qsort(buffer.aligned, numlen, sizeof(nums[0]), num_compare);
+    SDL_qsort_r(buffer_r.aligned, numlen, sizeof(nums[0]), num_compare_r, &a_global_var);
+    check_sort(buffer.aligned, buffer_r.aligned, numlen);
+
+    /* We can't test unaligned int sort because it's UB. */
+
+    SDL_free(buffer_r.aligned);
+    SDL_free(buffer.aligned);
+}
+
+static void
+check_non_word_sort(non_word_value *nums, non_word_value *r_nums, int numlen) {
+    int i;
+    char prev;
+
+    if (numlen > 0) {
+        prev = nums[0][0];
+    }
+    for (i = 1; i < numlen; i++) {
+        const char val = nums[i][0];
+        const char val2 = r_nums[i][0];
+        if ((val < prev) || (val != val2)) {
+            SDL_Log("sort is broken!");
+            qsort_is_broken = 1;
+            break;
+        }
+        prev = val;
+    }
+}
+
+static void
+test_sort_non_word(const char *desc, non_word_value *nums, int numlen)
 {
-    static int nums[1024 * 100];
-    static const int itervals[] = { SDL_arraysize(nums), 12 };
+    test_buffer buffer;
+    test_buffer buffer_r;
+
+    alloc_buffer(&buffer, sizeof(nums[0]), numlen);
+    alloc_buffer(&buffer_r, sizeof(nums[0]), numlen);
+
+    SDL_Log("test: %s non-word numlen=%d", desc, numlen);
+
+    /* Test aligned sort */
+    if (buffer.aligned != NULL) {
+        SDL_memcpy(buffer.aligned, nums, numlen * sizeof(nums[0]));
+        SDL_memcpy(buffer_r.aligned, nums, numlen * sizeof(nums[0]));
+    }
+    SDL_qsort(buffer.aligned, numlen, sizeof(nums[0]), num_compare_non_word);
+    SDL_qsort_r(buffer_r.aligned, numlen, sizeof(nums[0]), num_compare_non_word_r, &a_global_var);
+    check_non_word_sort(buffer.aligned, buffer_r.aligned, numlen);
+
+    /* Test non-aligned sort */
+    if (buffer.unaligned != NULL) {
+        SDL_memcpy(buffer.unaligned, nums, numlen * sizeof(nums[0]));
+        SDL_memcpy(buffer_r.unaligned, nums, numlen * sizeof(nums[0]));
+    }
+    SDL_qsort(buffer.unaligned, numlen, sizeof(nums[0]), num_compare_non_word);
+    SDL_qsort_r(buffer_r.unaligned, numlen, sizeof(nums[0]), num_compare_non_word_r, &a_global_var);
+    check_non_word_sort(buffer.unaligned, buffer_r.unaligned, numlen);
+
+    SDL_free(buffer_r.aligned);
+    SDL_free(buffer.aligned);
+}
+
+static void
+test_sort_non_transitive(int numlen) {
     int i;
-    int iteration;
-    SDLTest_RandomContext rndctx;
-    SDLTest_CommonState *state;
+    test_buffer buffer;
+    test_buffer non_word_buffer;
+    int *nums;
+    non_word_value *non_word_nums;
+
+    SDL_Log("test: non-transitive numlen=%d", (numlen));
+
+    alloc_buffer(&buffer, sizeof(nums[0]), numlen);
+    alloc_buffer(&non_word_buffer, sizeof(non_word_nums[0]), numlen);
+
+    /* Test aligned sort */
+    nums = buffer.aligned;
+    non_word_nums = non_word_buffer.aligned;
+    for (i = 0; i < numlen; i++) {
+        nums[i] = numlen - i;
+        non_word_nums[i][0] = (char)nums[i];
+    }
+
+    SDL_qsort(nums, numlen, sizeof(nums[0]), num_compare_non_transitive);
+    SDL_qsort(non_word_nums, numlen, sizeof(non_word_nums[0]), num_compare_non_word_non_transitive);
+
+    /* What's inside doesn't matter for random comparison */
+    SDL_qsort(nums, numlen, sizeof(nums[0]), num_compare_random_any);
+    SDL_qsort(non_word_nums, numlen, sizeof(non_word_nums[0]), num_compare_random_any);
+
+    /* Test non-aligned sort */
+    non_word_nums = non_word_buffer.unaligned;
+    for (i = 0; i < numlen; i++) {
+        non_word_nums[i][0] = (char)(numlen - i);
+    }
+
+    SDL_qsort(non_word_nums, numlen, sizeof(non_word_nums[0]), num_compare_non_word_non_transitive);
+    SDL_qsort(non_word_nums, numlen, sizeof(non_word_nums[0]), num_compare_random_any);
+
+    SDL_free(buffer.aligned);
+    SDL_free(non_word_buffer.aligned);
+}
+
+int main(int argc, char *argv[])
+{
+    static int nums[1024 * 128];
+    static non_word_value non_word_nums[1024 * 128];
+
+    SDL_assert(SDL_arraysize(nums) == SDL_arraysize(non_word_nums));
+
+    /* Test truncation points */
+    static const int itervals[] = { 0, 12, 15, 12 * sizeof(int), SDL_arraysize(nums) };
+    /* Non-transitive sorting consumes much more CPU, use smaller value */
+    static const int itervals_non_transitive[] = { 0, 12, 15, 12 * sizeof(int), 16384};
+
+    int i = 0;
+    int iteration = 0;
+    SDLTest_CommonState *state = NULL;
     int seed_seen = 0;
 
     SDL_zero(rndctx);
+    qsort_is_broken = 0;
 
     /* Initialize test framework */
     state = SDLTest_CommonCreateState(argv, 0);
@@ -123,27 +320,43 @@ int main(int argc, char *argv[])
 
         for (i = 0; i < arraylen; i++) {
             nums[i] = i;
+            non_word_nums[i][0] = (char)i;
         }
         test_sort("already sorted", nums, arraylen);
+        test_sort_non_word("already_sorted", non_word_nums, arraylen);
 
-        for (i = 0; i < arraylen; i++) {
-            nums[i] = i;
+        if (arraylen > 0) {
+            for (i = 0; i < arraylen; i++) {
+                nums[i] = i;
+                non_word_nums[i][0] = (char)i;
+            }
+            nums[arraylen - 1] = -1;
+            test_sort("already sorted except last element", nums, arraylen);
+            test_sort_non_word("already sorted except last element", non_word_nums, arraylen);
         }
-        nums[arraylen - 1] = -1;
-        test_sort("already sorted except last element", nums, arraylen);
 
         for (i = 0; i < arraylen; i++) {
             nums[i] = (arraylen - 1) - i;
+            non_word_nums[i][0] = (char)i;
         }
         test_sort("reverse sorted", nums, arraylen);
+        test_sort_non_word("reverse sorted", non_word_nums, arraylen);
 
         for (i = 0; i < arraylen; i++) {
             nums[i] = SDLTest_RandomInt(&rndctx);
+            non_word_nums[i][0] = (char)i;
         }
         test_sort("random sorted", nums, arraylen);
+        test_sort_non_word("random sorted", non_word_nums, arraylen);
+    }
+
+    for (iteration = 0; iteration < SDL_arraysize(itervals_non_transitive); iteration++) {
+        const int arraylen = itervals_non_transitive[iteration];
+
+        test_sort_non_transitive(arraylen);
     }
 
     SDLTest_CommonDestroyState(state);
 
-    return 0;
+    return qsort_is_broken;
 }