Initial commit

src/util/darray.h

@@ -0,0 +1,53 @@
+#ifndef JNR_DARRAY_H
+#define JNR_DARRAY_H
+
+/*
+ * Simple type-safe dynamic array using macros.
+ *
+ * Usage:
+ *   DArray(int) nums = {0};
+ *   da_push(&nums, 42);
+ *   da_push(&nums, 99);
+ *   for (int i = 0; i < nums.count; i++) printf("%d\n", nums.items[i]);
+ *   da_free(&nums);
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#define DArray(T) struct { T *items; int count; int capacity; }
+
+#define da_push(arr, val) do {                                          \
+    if ((arr)->count >= (arr)->capacity) {                              \
+        (arr)->capacity = (arr)->capacity ? (arr)->capacity * 2 : 8;   \
+        (arr)->items = realloc((arr)->items,                            \
+            (arr)->capacity * sizeof(*(arr)->items));                   \
+    }                                                                   \
+    (arr)->items[(arr)->count++] = (val);                               \
+} while (0)
+
+#define da_pop(arr) ((arr)->items[--(arr)->count])
+
+#define da_clear(arr) ((arr)->count = 0)
+
+#define da_free(arr) do {      \
+    free((arr)->items);        \
+    (arr)->items = NULL;       \
+    (arr)->count = 0;          \
+    (arr)->capacity = 0;       \
+} while (0)
+
+#define da_remove(arr, idx) do {                                        \
+    if ((idx) < (arr)->count - 1) {                                    \
+        memmove(&(arr)->items[(idx)], &(arr)->items[(idx) + 1],        \
+            ((arr)->count - (idx) - 1) * sizeof(*(arr)->items));       \
+    }                                                                   \
+    (arr)->count--;                                                     \
+} while (0)
+
+/* Swap-remove: O(1) but doesn't preserve order */
+#define da_remove_fast(arr, idx) do {                                   \
+    (arr)->items[(idx)] = (arr)->items[--(arr)->count];                 \
+} while (0)
+
+#endif /* JNR_DARRAY_H */