feat: add slotted page skeleton with TDD cycle for page_create

format: storage.h

CMakeLists.txt

@@ -71,7 +71,13 @@ target_include_directories(pauldb
 # Tests (CTest)
 # ---------------------------------------------------------------------------
 enable_testing()
-# add_subdirectory(test)   # einkommentieren sobald erste Tests da sind
+
+add_executable(test_page
+    test/storage/test_page.c
+    src/storage/page.c
+)
+target_include_directories(test_page PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include)
+add_test(NAME test_page COMMAND test_page)
 
 # ---------------------------------------------------------------------------
 # Installationsregeln (fur package() in conanfile.py)

include/pauldb/storage.h

@@ -6,42 +6,110 @@
 #include <stddef.h>
 
 #ifdef __cplusplus
-extern "C" {
+extern "C"
+{
+
+
 
 #endif
 
 /* --- Page Management --- */
 typedef struct Page Page;
 
-Page *page_create(uint32_t page_id);
+Page *
+page_create
+(
+	uint32_t page_id
+);
 
-int page_insert(Page *p, const void *data, size_t len);
+int
+page_insert
+(
+	Page *p,
+	const void *data,
+	size_t len
+);
 
-void *page_get(Page *p, uint16_t slot_id, size_t *out_len);
+void *
+page_get
+(
+	Page *p,
+	uint16_t slot_id,
+	size_t *out_len
+);
 
-void page_free(Page *p);
+void
+page_free
+(
+	Page *p
+);
 
 /* --- Heap (Multi-Page Row Store / Delta) --- */
 typedef struct Heap Heap;
 
-Heap *heap_create(void);
+Heap *
+heap_create
+(
+	void
+);
 
-int heap_insert(Heap *h, const void *data, size_t len);
+int
+heap_insert
+(
+	Heap *h,
+	const void *data,
+	size_t len
+);
 
-void heap_full_scan(Heap *h, void (*callback)(const void *, size_t));
+void
+heap_full_scan
+(
+	Heap *h,
+	void (*callback)
+	(
+		const void *,
+		size_t
+	)
+);
 
-void heap_free(Heap *h);
+void
+heap_free
+(
+	Heap *h
+);
 
 /* --- B+Tree Index --- */
 typedef struct BTree BTree;
 
-BTree *btree_create(void);
+BTree *
+btree_create
+(
+	void
+);
 
-int btree_insert(BTree *bt, int64_t key, uint32_t page_id, uint16_t slot_id);
+int
+btree_insert
+(
+	BTree *bt,
+	int64_t key,
+	uint32_t page_id,
+	uint16_t slot_id
+);
 
-int btree_lookup(BTree *bt, int64_t key, uint32_t *out_page, uint16_t *out_slot);
+int
+btree_lookup
+(
+	BTree *bt,
+	int64_t key,
+	uint32_t *out_page,
+	uint16_t *out_slot
+);
 
-void btree_free(BTree *bt);
+void
+btree_free
+(
+	BTree *bt
+);
 
 #ifdef __cplusplus
 }

src/storage/page.c

@@ -1,2 +1,78 @@
-/* page.c - Storage Engine (C) */
+/* src/storage/page.c
+ * Slotted Page - Storage Engine (C)
+ *
+ * Layout (4 KiB):
+ *
+ *  Byte 0                                              Byte 4095
+ *  +----------+--------+--------+---   ---+------+------+
+ *  | Header   | Slot 0 | Slot 1 |  free   |Tuple1|Tuple0|
+ *  +----------+--------+--------+---   ---+------+------+
+ *               slots -->                <-- tuples
+ *
+ * Header  : page_id, num_slots, free_space_offset
+ * Slot    : (offset, length) - wo im raw-Array liegt das Tuple?
+ * free_space_offset: naechste Schreibposition fuer Tuple-Daten
+ *                    startet bei PAGE_SIZE, nimmt ab
+ */
 #include "pauldb/storage.h"
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define PAGE_SIZE 4096
+
+/* ---- interne Typen (nur in dieser Datei sichtbar) ---- */
+
+typedef struct {
+    uint32_t page_id;
+    uint16_t num_slots;
+    uint16_t free_space_offset;
+} PageHeader;
+
+typedef struct {
+    uint16_t offset;
+    uint16_t length;
+} Slot;
+
+/* oeffentliche Page-Struktur (opak nach aussen) */
+struct Page {
+    uint8_t raw[PAGE_SIZE];
+};
+
+/* ---- Hilfsfunktionen ---- */
+
+static PageHeader *header(Page *p) {
+    return (PageHeader *)p->raw;
+}
+
+/* ---- API ---- */
+
+Page *page_create(uint32_t page_id) {
+    Page *p = malloc(sizeof(Page));
+    if (!p) return NULL;
+
+    memset(p->raw, 0, PAGE_SIZE);
+
+    PageHeader *h  = header(p);
+    h->page_id          = page_id;
+    h->num_slots        = 0;
+    h->free_space_offset = PAGE_SIZE;
+
+    return p;
+}
+
+void page_free(Page *p) {
+    free(p);
+}
+
+/* page_insert und page_get folgen im naechsten TDD-Zyklus */
+int page_insert(Page *p, const void *data, size_t len) {
+    (void)p; (void)data; (void)len;
+    return -1; /* noch nicht implementiert */
+}
+
+void *page_get(Page *p, uint16_t slot_id, size_t *out_len) {
+    (void)p; (void)slot_id; (void)out_len;
+    return NULL; /* noch nicht implementiert */
+}

test/storage/test_page.c

@@ -0,0 +1,34 @@
+/* test/storage/test_page.c
+ *
+ * TDD-Zyklus: test_page_create
+ * RED   -> diese Datei schreiben, noch kein page.c -> Linker-Fehler
+ * GREEN -> page_create() + page_free() in page.c implementieren
+ */
+#include <assert.h>
+#include <stdio.h>
+
+#include "pauldb/storage.h"
+
+static void
+test_create_returns_non_null
+(
+	void
+)
+{
+	Page *p = page_create(42);
+	assert(p != NULL);
+	page_free(p);
+	printf("  OK: page_create(42) returns non-NULL\n");
+}
+
+int
+main
+(
+	void
+)
+{
+	printf("=== test_page ===\n");
+	test_create_returns_non_null();
+	printf("All tests passed.\n");
+	return 0;
+}