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+/*
+ * Simple & stupid dynamic array single-header implementation.  You can use the
+ * macros defined in this file with any structure that has the following fields:
+ *
+ *  struct dyn_array {
+ *      T *buf  // Array of items
+ *      N  len  // Length of array
+ *      N  cap  // Capacity of array
+ *  }
+ *
+ * The type ‘T’ is whatever type you want to store.  The type ‘N’ is any numeric
+ * type — most likely ‘size_t’ — but it could be sized as well.
+ *
+ * The daremove() macro also doesn’t bother with shrinking your array when the
+ * length is far lower than the capacity.  If you care about that, do it
+ * yourself.
+ *
+ * Remember to call free() on your dynamic arrays ‘buf’ field after use.
+ *
+ *
+ * Macro Overview
+ * ――――――――――――――
+ * The argument ‘a’ to all of the below macros is a pointer to the dynamic array
+ * structure.
+ *
+ * dainit(a, n)              Initialize the array with a capacity of ‘n’ items.
+ * dapush(a, x)              Append the item ‘x’ to the array
+ * daremove(a, x)            Remove the item at index ‘x’ from the array
+ * da_remove_range(a, x, y)  Remove the items between the range [x, y)
+ * da_foreach(a, p)          Iterate the pointer ‘p’ over each element of the
+ *                           array.  The type of ‘p’ is inferred.
+ *
+ * The ‘dapush()’ macro will double the arrays capacity when it gets full.  If
+ * you would like your arrays to grow with a different scale, edit this file.
+ *
+ *
+ * Example
+ * ―――――――
+ *
+ * struct {
+ *     int *buf;
+ *     size_t len, cap;
+ * } nums;
+ *
+ * // Initialize nums with capacity == 4
+ * dainit(&nums, 4);
+ *
+ * // Append 69, 1337, and 420 to nums
+ * dapush(&nums, 69);
+ * dapush(&nums, 1337);
+ * dapush(&nums, 420);
+ *
+ * da_foreach (&nums, n) {
+ *     int x = *n << 1;
+ *     printf("n = %d; n² = %d\n", *n, x);
+ * }
+ *
+ * // Remove 1337 and 420 from nums
+ * da_remove_range(&nums, 1, 3);
+ *
+ * // Remove 69 from nums
+ * daremove(&nums, 0);
+ */
+
+#ifndef MANGO_DA_H
+#define MANGO_DA_H
+
+#include <err.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if __STDC_VERSION__ >= 202311L
+#	define DA_NULL nullptr
+#else
+#	define DA_NULL NULL
+#endif
+
+#define DA_ALLOC(p, n) \
+	do { \
+		if ((n) && SIZE_MAX / (n) < sizeof(*(p))) { \
+			errno = EOVERFLOW; \
+			err(EXIT_FAILURE, "realloc"); \
+		} \
+		if (!((p) = realloc((p), (n) * sizeof(*(p))))) \
+			err(EXIT_FAILURE, "realloc"); \
+	} while (0)
+
+#define dainit(a, n) \
+	do { \
+		(a)->buf = DA_NULL; \
+		(a)->cap = (n); \
+		(a)->len = 0; \
+		if (n) \
+			DA_ALLOC((a)->buf, (a)->cap); \
+	} while (0)
+
+#define dapush(a, x) \
+	do { \
+		if ((a)->len >= (a)->cap) { \
+			(a)->cap = (a)->cap ? (a)->cap * 2 : 1; \
+			DA_ALLOC((a)->buf, (a)->cap); \
+		} \
+		(a)->buf[(a)->len++] = (x); \
+	} while (0)
+
+#define daremove(a, i) da_remove_range((a), (i), (i) + 1)
+
+#define da_remove_range(a, i, j) \
+	do { \
+		memmove((a)->buf + (i), (a)->buf + (j), \
+		        ((a)->len - (j)) * sizeof(*(a)->buf)); \
+		(a)->len -= j - i; \
+	} while (0)
+
+#define da_foreach(a, p) \
+	for (typeof((a)->buf) p = (a)->buf; (size_t)(p - (a)->buf) < (a)->len; p++)
+
+#endif /* !MANGO_DA_H */