feat: page_insert implemented in page.c

src/storage/page.c

@@ -79,10 +79,28 @@ page_free(Page * p)
 int
 page_insert(Page * p, const void * data, size_t len)
 {
-    (void) p;
-    (void) data;
-    (void) len;
-    return -1; /* noch nicht implementiert */
+    PageHeader * h = header(p);
+
+    /* Wo endet der letzte Slot? */
+    size_t slots_end = sizeof(PageHeader) + ((h->num_slots + 1) * sizeof(Slot));
+
+    /* Passt das neue Tuple noch rein? */
+    if (h->free_space_offset - len < slots_end) return -1; /* Page voll */
+
+    /* Tuple-Daten von hinten schreiben */
+    h->free_space_offset -= (uint16_t) len;
+    memcpy(p->raw + h->free_space_offset, data, len);
+
+    /* Neuen Slot anlegen */
+    Slot * s = (Slot *) (p->raw + sizeof(PageHeader)) + h->num_slots;
+    s->offset = h->free_space_offset;
+    s->length = (uint16_t) len;
+
+    /* Slot-ID zurueckgeben, dann Counter erhoehen */
+    uint16_t slot_id = h->num_slots;
+    h->num_slots++;
+
+    return (int) slot_id;
 }
 
 void *