erase() should really now set proper values to 0 after move

tests/erase_stress_test.c

@@ -0,0 +1,418 @@
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <stdio.h>
+#include <time.h>
+
+#define CAPACITY 1024
+#define nullptr ((void*)0)
+
+typedef struct {
+    char* arr;
+    size_t size;
+    size_t capacity;
+} Vec8_t;
+
+Vec8_t create(const Vec8_t* input) {
+    Vec8_t vec = { .arr = nullptr, .size = 0, .capacity = CAPACITY };
+    if (input != nullptr && input->size > 0) vec.size = input->size + 1;
+    vec.arr = calloc(vec.capacity, sizeof(char));
+    return vec;
+}
+
+void delete(Vec8_t* vec) {
+    if (vec->arr != nullptr) { free(vec->arr); vec->arr = nullptr; }
+}
+
+Vec8_t add_back(Vec8_t* vec, const char val) {
+    if (vec->size >= vec->capacity) {
+        vec->capacity *= 2;
+        char* nvec = reallocf(vec->arr, vec->capacity * sizeof(char));
+        if (nvec == NULL) return *vec;
+        vec->arr = nvec;
+    }
+    vec->arr[vec->size] = val;
+    vec->size++;
+    return *vec;
+}
+
+// Exact copy of src/main.c single erase (lines 128-137)
+__attribute__((overloadable)) Vec8_t*
+erase(Vec8_t* vec, const int iter) {
+        if(vec == nullptr) return nullptr;
+        if(vec->arr == nullptr) return nullptr;
+        if(iter >= vec->size) return nullptr;
+        memmove(&vec->arr[iter], &vec->arr[iter + 1], (vec->size - iter - 1) * sizeof(char));
+        vec->arr[vec->size - 1] = 0;
+        vec->size--;
+        return vec;
+}
+
+// Exact copy of src/main.c range erase (lines 139-152)
+__attribute__((overloadable)) Vec8_t*
+erase(Vec8_t* vec, const int iter_start, const int iter_end) {
+        if(vec == nullptr) return nullptr;
+        if(vec->arr == nullptr) return nullptr;
+        if(iter_start < 0 || iter_end >= vec->size) return nullptr;
+        if(iter_start >= iter_end) return nullptr;
+        size_t diff = iter_end - iter_start;
+        memmove(&vec->arr[iter_start], &vec->arr[iter_end], (vec->size - iter_end) * sizeof(char));
+        for(size_t i = vec->size - 1; i > iter_end; i--) {
+                vec->arr[i] = 0;
+        }
+        vec->size -= diff;
+        return vec;
+}
+
+void print_vec(const Vec8_t* vec) {
+    for (int i = 0; i < vec->size; i++) printf("%c ", vec->arr[i]);
+    printf("(size=%zu)\n", vec->size);
+}
+
+// Test 1: Basic single erase
+void test_single_erase_basic() {
+    printf("Test: Single erase basic\n");
+    Vec8_t vec = create(nullptr);
+    for (int i = 0; i < 10; i++) add_back(&vec, 'a' + i);
+
+    erase(&vec, 2); // Erase 'c'
+
+    assert(vec.size == 9);
+    assert(vec.arr[0] == 'a');
+    assert(vec.arr[1] == 'b');
+    assert(vec.arr[2] == 'd'); // Shifted correctly
+    assert(vec.arr[8] == 'j'); // Last element correct
+    printf("PASS\n\n");
+    delete(&vec);
+}
+
+// Test 2: Single erase at boundaries
+void test_single_erase_boundaries() {
+    printf("Test: Single erase at boundaries\n");
+    Vec8_t vec = create(nullptr);
+    for (int i = 0; i < 5; i++) add_back(&vec, 'a' + i);
+
+    // Erase first element
+    erase(&vec, 0);
+    assert(vec.size == 4);
+    assert(vec.arr[0] == 'b');
+    printf("Erase first: PASS\n");
+
+    // Reset
+    delete(&vec);
+    vec = create(nullptr);
+    for (int i = 0; i < 5; i++) add_back(&vec, 'a' + i);
+
+    // Erase last element
+    erase(&vec, 4);
+    assert(vec.size == 4);
+    assert(vec.arr[3] == 'd');
+    printf("Erase last: PASS\n");
+
+    delete(&vec);
+    printf("\n");
+}
+
+// Test 3: Single erase invalid inputs
+void test_single_erase_invalid() {
+    printf("Test: Single erase invalid inputs\n");
+    Vec8_t vec = create(nullptr);
+    for (int i = 0; i < 5; i++) add_back(&vec, 'a' + i);
+
+    // Erase with negative index
+    assert(erase(&vec, -1) == nullptr);
+
+    // Erase with out-of-bounds index
+    assert(erase(&vec, 10) == nullptr);
+    assert(erase(&vec, 5) == nullptr);
+
+    // Erase on null vector
+    assert(erase(nullptr, 0) == nullptr);
+
+    // Erase on vector with null arr
+    Vec8_t vec2 = { .arr = nullptr, .size = 0, .capacity = 0 };
+    assert(erase(&vec2, 0) == nullptr);
+
+    printf("PASS\n\n");
+    delete(&vec);
+}
+
+// Test 4: Range erase basic
+void test_range_erase_basic() {
+    printf("Test: Range erase basic\n");
+    Vec8_t vec = create(nullptr);
+    for (int i = 0; i < 10; i++) add_back(&vec, 'a' + i);
+
+    erase(&vec, 2, 4); // Erase [2,4) -> 'c','d'
+
+    printf("After erase(2,4): ");
+    print_vec(&vec);
+
+    assert(vec.size == 8);
+    assert(vec.arr[0] == 'a');
+    assert(vec.arr[1] == 'b');
+    assert(vec.arr[2] == 'e'); // Shifted correctly
+    assert(vec.arr[7] == 'j'); // Last element correct
+
+    // Check that valid data is not zeroed incorrectly
+    for (int i = 0; i < vec.size; i++) {
+        assert(vec.arr[i] != 0); // Valid positions should not be zero
+    }
+
+    printf("PASS\n\n");
+    delete(&vec);
+}
+
+// Test 5: Range erase - verify zeroing works correctly now
+void test_range_erase_zeroing_fixed() {
+    printf("Test: Range erase zeroing verification\n");
+    Vec8_t vec = create(nullptr);
+    for (int i = 0; i < 10; i++) add_back(&vec, 'a' + i);
+
+    erase(&vec, 2, 4);
+
+    printf("After erase(2,4): ");
+    print_vec(&vec);
+
+    // Verify valid data is not zeroed
+    for (int i = 0; i < vec.size; i++) {
+        assert(vec.arr[i] != 0); // Valid positions should not be zero
+    }
+
+    // Verify that positions beyond new size are zeroed
+    // (The zeroing loop should zero from vec.size-1 down to iter_end)
+    printf("Zeroing verification: ");
+    int all_valid = 1;
+    for (int i = 0; i < vec.size; i++) {
+        if (vec.arr[i] == 0) {
+            printf("BUG: arr[%d] is zero but should be valid! ", i);
+            all_valid = 0;
+        }
+    }
+    if (all_valid) printf("PASS");
+
+    printf("\n\n");
+    delete(&vec);
+}
+
+// Test 6: Range erase to end
+void test_range_erase_to_end() {
+    printf("Test: Range erase to end\n");
+    Vec8_t vec = create(nullptr);
+    for (int i = 0; i < 10; i++) add_back(&vec, 'a' + i);
+
+    Vec8_t* res = erase(&vec, 2, 10); // Erase [2,10)
+    assert(res != nullptr);
+    assert(vec.size == 2);
+    assert(vec.arr[0] == 'a');
+    assert(vec.arr[1] == 'b');
+
+    printf("PASS\n\n");
+    delete(&vec);
+}
+
+// Test 7: Range erase invalid inputs
+void test_range_erase_invalid() {
+    printf("Test: Range erase invalid inputs\n");
+    Vec8_t vec = create(nullptr);
+    for (int i = 0; i < 5; i++) add_back(&vec, 'a' + i);
+
+    // Invalid start
+    assert(erase(&vec, -1, 3) == nullptr);
+
+    // Invalid end (>= size now, not just >)
+    assert(erase(&vec, 0, 5) == nullptr); // 5 >= size (5)
+
+    // Start >= end now returns nullptr
+    assert(erase(&vec, 3, 2) == nullptr); // start >= end
+    assert(erase(&vec, 2, 2) == nullptr); // start == end
+
+    // Null vector
+    assert(erase(nullptr, 0, 1) == nullptr);
+
+    printf("PASS\n\n");
+    delete(&vec);
+}
+
+// Test 8: Large vector single erase
+void test_large_single_erase() {
+    printf("Test: Large vector single erase (100k elements)\n");
+    Vec8_t vec = create(nullptr);
+    for (int i = 0; i < 100000; i++) add_back(&vec, (char)(i % 256));
+
+    erase(&vec, 0); // Erase front
+    assert(vec.size == 99999);
+    assert(vec.arr[0] == 1);
+
+    erase(&vec, 50000); // Erase middle
+    assert(vec.size == 99998);
+    assert(vec.arr[50000] == 2); // After erasing index 1 (value 1), index 50000 is now value 2
+
+    printf("PASS\n\n");
+    delete(&vec);
+}
+
+// Test 9: Large vector range erase
+void test_large_range_erase() {
+    printf("Test: Large vector range erase (100k elements, erase 10k)\n");
+    Vec8_t vec = create(nullptr);
+    for (int i = 0; i < 100000; i++) add_back(&vec, (char)(i % 256));
+
+    erase(&vec, 10000, 20000); // Erase 10k elements
+    assert(vec.size == 90000);
+    assert(vec.arr[10000] == (char)(20000 % 256)); // First element after erased range
+
+    printf("PASS\n\n");
+    delete(&vec);
+}
+
+// Test 10: Repeated single erasures
+void test_repeated_single_erase() {
+    printf("Test: Repeated single erasures until empty\n");
+    Vec8_t vec = create(nullptr);
+    for (int i = 0; i < 100; i++) add_back(&vec, 'a' + (i % 26));
+
+    size_t initial_size = vec.size;
+    for (int i = 0; i < initial_size; i++) {
+        erase(&vec, 0); // Always erase first element
+    }
+
+    assert(vec.size == 0);
+    printf("PASS\n\n");
+    delete(&vec);
+}
+
+// Test 11: Stress - random erasures
+void test_random_erasures() {
+    printf("Test: Random erasures (1000 rounds)\n");
+    srand((unsigned int)time(NULL));
+
+    for (int round = 0; round < 1000; round++) {
+        Vec8_t vec = create(nullptr);
+        int num_elements = rand() % 1000 + 10;
+        for (int i = 0; i < num_elements; i++) add_back(&vec, (char)(rand() % 256));
+
+        int num_erasures = rand() % 50;
+        for (int j = 0; j < num_erasures && vec.size > 0; j++) {
+            int idx = rand() % vec.size;
+            erase(&vec, idx);
+        }
+
+        // Verify integrity
+        for (int i = 0; i < vec.size; i++) {
+            // Just check that we can access without crashing
+            char val = vec.arr[i];
+            (void)val;
+        }
+
+        delete(&vec);
+    }
+
+    printf("PASS\n\n");
+}
+
+// Test 12: Stress - random range erasures
+void test_random_range_erasures() {
+    printf("Test: Random range erasures (1000 rounds)\n");
+    srand((unsigned int)time(NULL));
+
+    for (int round = 0; round < 1000; round++) {
+        Vec8_t vec = create(nullptr);
+        int num_elements = rand() % 1000 + 10;
+        for (int i = 0; i < num_elements; i++) add_back(&vec, (char)(rand() % 256));
+
+        int num_erasures = rand() % 20;
+        for (int j = 0; j < num_erasures && vec.size > 1; j++) {
+            int start = rand() % (vec.size - 1);
+            int end = start + rand() % (vec.size - start) + 1;
+            if (end > vec.size) end = vec.size;
+            erase(&vec, start, end);
+        }
+
+        // Verify integrity
+        for (int i = 0; i < vec.size; i++) {
+            char val = vec.arr[i];
+            (void)val;
+        }
+
+        delete(&vec);
+    }
+
+    printf("PASS\n\n");
+}
+
+// Test 13: Erase all elements one by one
+void test_erase_all_single() {
+    printf("Test: Erase all elements one by one\n");
+    Vec8_t vec = create(nullptr);
+    for (int i = 0; i < 1000; i++) add_back(&vec, 'a' + (i % 26));
+
+    while (vec.size > 0) {
+        erase(&vec, 0);
+    }
+
+    assert(vec.size == 0);
+    printf("PASS\n\n");
+    delete(&vec);
+}
+
+// Test 14: Erase all elements with range erase
+void test_erase_all_range() {
+    printf("Test: Erase all elements with range erase\n");
+    Vec8_t vec = create(nullptr);
+    for (int i = 0; i < 1000; i++) add_back(&vec, 'a' + (i % 26));
+
+    erase(&vec, 0, vec.size);
+
+    assert(vec.size == 0);
+    printf("PASS\n\n");
+    delete(&vec);
+}
+
+// Test 15: Memory stress - large vector, erase in middle repeatedly
+void test_memory_stress() {
+    printf("Test: Memory stress - large vector, repeated middle erasure\n");
+    Vec8_t vec = create(nullptr);
+
+    // Add 1 million elements
+    for (int i = 0; i < 1000000; i++) {
+        add_back(&vec, (char)(i % 256));
+    }
+
+    printf("  Created vector with %zu elements\n", vec.size);
+
+    // Erase from middle repeatedly
+    for (int i = 0; i < 10000; i++) {
+        if (vec.size == 0) break;
+        int idx = vec.size / 2;
+        erase(&vec, idx);
+    }
+
+    printf("  After 10k middle erasures, size = %zu\n", vec.size);
+
+    delete(&vec);
+    printf("PASS\n\n");
+}
+
+    int main() {
+    printf("=== ERASE STRESS TEST SUITE ===\n\n");
+
+    test_single_erase_basic();
+    test_single_erase_boundaries();
+    test_single_erase_invalid();
+    test_range_erase_basic();
+    test_range_erase_zeroing_fixed();
+    test_range_erase_to_end();
+    test_range_erase_invalid();
+    test_large_single_erase();
+    test_large_range_erase();
+    test_repeated_single_erase();
+    test_random_erasures();
+    test_random_range_erasures();
+    test_erase_all_single();
+    test_erase_all_range();
+    test_memory_stress();
+
+    printf("=== ALL TESTS COMPLETED ===\n");
+    return 0;
+}