Introduce VecDeque

Introduce a double-ended queue implemented with a growable ring buffer.

Inspired from the Rust VecDeque type:
<https://doc.rust-lang.org/std/collections/struct.VecDeque.html>

app/tests/test_vecdeque.c

@@ -0,0 +1,197 @@
+#include "common.h"
+
+#include <assert.h>
+
+#include "util/vecdeque.h"
+
+#define pr(pv) \
+({ \
+    fprintf(stderr, "cap=%lu origin=%lu size=%lu\n", (pv)->cap, (pv)->origin, (pv)->size); \
+    for (size_t i = 0; i < (pv)->cap; ++i) \
+        fprintf(stderr, "%d ", (pv)->data[i]); \
+    fprintf(stderr, "\n"); \
+})
+
+static void test_vecdeque_push_pop(void) {
+    struct SC_VECDEQUE(int) vdq = SC_VECDEQUE_INITIALIZER;
+
+    assert(sc_vecdeque_is_empty(&vdq));
+    assert(sc_vecdeque_size(&vdq) == 0);
+
+    bool ok = sc_vecdeque_push(&vdq, 5);
+    assert(ok);
+    assert(sc_vecdeque_size(&vdq) == 1);
+
+    ok = sc_vecdeque_push(&vdq, 12);
+    assert(ok);
+    assert(sc_vecdeque_size(&vdq) == 2);
+
+    int v = sc_vecdeque_pop(&vdq);
+    assert(v == 5);
+    assert(sc_vecdeque_size(&vdq) == 1);
+
+    ok = sc_vecdeque_push(&vdq, 7);
+    assert(ok);
+    assert(sc_vecdeque_size(&vdq) == 2);
+
+    int *p = sc_vecdeque_popref(&vdq);
+    assert(p);
+    assert(*p == 12);
+    assert(sc_vecdeque_size(&vdq) == 1);
+
+    v = sc_vecdeque_pop(&vdq);
+    assert(v == 7);
+    assert(sc_vecdeque_size(&vdq) == 0);
+    assert(sc_vecdeque_is_empty(&vdq));
+
+    sc_vecdeque_destroy(&vdq);
+}
+
+static void test_vecdeque_reserve(void) {
+    struct SC_VECDEQUE(int) vdq = SC_VECDEQUE_INITIALIZER;
+
+    bool ok = sc_vecdeque_reserve(&vdq, 20);
+    assert(ok);
+    assert(vdq.cap == 20);
+
+    assert(sc_vecdeque_size(&vdq) == 0);
+
+    for (size_t i = 0; i < 20; ++i) {
+        ok = sc_vecdeque_push(&vdq, i);
+        assert(ok);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 20);
+
+    // It is now full
+
+    for (int i = 0; i < 5; ++i) {
+        int v = sc_vecdeque_pop(&vdq);
+        assert(v == i);
+    }
+    assert(sc_vecdeque_size(&vdq) == 15);
+
+    for (int i = 20; i < 25; ++i) {
+        ok = sc_vecdeque_push(&vdq, i);
+        assert(ok);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 20);
+    assert(vdq.cap == 20);
+
+    // Now, the content wraps around the ring buffer:
+    // 20 21 22 23 24  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19
+    //                 ^
+    //                 origin
+
+    // It is now full, let's reserve some space
+    ok = sc_vecdeque_reserve(&vdq, 30);
+    assert(ok);
+    assert(vdq.cap == 30);
+
+    assert(sc_vecdeque_size(&vdq) == 20);
+
+    for (int i = 0; i < 20; ++i) {
+        // We should retrieve the items we inserted in order
+        int v = sc_vecdeque_pop(&vdq);
+        assert(v == i + 5);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 0);
+
+    sc_vecdeque_destroy(&vdq);
+}
+
+static void test_vecdeque_grow() {
+    struct SC_VECDEQUE(int) vdq = SC_VECDEQUE_INITIALIZER;
+
+    bool ok = sc_vecdeque_reserve(&vdq, 20);
+    assert(ok);
+    assert(vdq.cap == 20);
+
+    assert(sc_vecdeque_size(&vdq) == 0);
+
+    for (int i = 0; i < 500; ++i) {
+        ok = sc_vecdeque_push(&vdq, i);
+        assert(ok);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 500);
+
+    for (int i = 0; i < 100; ++i) {
+        int v = sc_vecdeque_pop(&vdq);
+        assert(v == i);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 400);
+
+    for (int i = 500; i < 1000; ++i) {
+        ok = sc_vecdeque_push(&vdq, i);
+        assert(ok);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 900);
+
+    for (int i = 100; i < 1000; ++i) {
+        int v = sc_vecdeque_pop(&vdq);
+        assert(v == i);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 0);
+
+    sc_vecdeque_destroy(&vdq);
+}
+
+static void test_vecdeque_push_hole() {
+    struct SC_VECDEQUE(int) vdq = SC_VECDEQUE_INITIALIZER;
+
+    bool ok = sc_vecdeque_reserve(&vdq, 20);
+    assert(ok);
+    assert(vdq.cap == 20);
+
+    assert(sc_vecdeque_size(&vdq) == 0);
+
+    for (int i = 0; i < 20; ++i) {
+        int *p = sc_vecdeque_push_hole(&vdq);
+        assert(p);
+        *p = i * 10;
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 20);
+
+    for (int i = 0; i < 10; ++i) {
+        int v = sc_vecdeque_pop(&vdq);
+        assert(v == i * 10);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 10);
+
+    for (int i = 20; i < 30; ++i) {
+        int *p = sc_vecdeque_push_hole(&vdq);
+        assert(p);
+        *p = i * 10;
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 20);
+
+    for (int i = 10; i < 30; ++i) {
+        int v = sc_vecdeque_pop(&vdq);
+        assert(v == i * 10);
+    }
+
+    assert(sc_vecdeque_size(&vdq) == 0);
+
+    sc_vecdeque_destroy(&vdq);
+}
+
+int main(int argc, char *argv[]) {
+    (void) argc;
+    (void) argv;
+
+    test_vecdeque_push_pop();
+    test_vecdeque_reserve();
+    test_vecdeque_grow();
+    test_vecdeque_push_hole();
+
+    return 0;
+}