1 files changed, 66 insertions, 0 deletions
diff --git a/src/array.h b/src/array.h
new file mode 100644
index 000000000..2d77c71a0
--- /dev/null
+++ b/src/array.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_array_h__
+#define INCLUDE_array_h__
+
+#include "util.h"
+
+/*
+ * Use this to declare a typesafe resizable array of items, a la:
+ *
+ *     git_array_t(int) my_ints = GIT_ARRAY_INIT;
+ *     ...
+ *     int *i = git_array_alloc(my_ints);
+ *     GITERR_CHECK_ALLOC(i);
+ *     ...
+ *     git_array_clear(my_ints);
+ *
+ * You may also want to do things like:
+ *
+ *     typedef git_array_t(my_struct) my_struct_array_t;
+ */
+#define git_array_t(type) struct { type *ptr; uint32_t size, asize; }
+
+#define GIT_ARRAY_INIT { NULL, 0, 0 }
+
+#define git_array_init(a) \
+	do { (a).size = (a).asize = 0; (a).ptr = NULL; } while (0)
+
+#define git_array_clear(a) \
+	do { git__free((a).ptr); git_array_init(a); } while (0)
+
+#define GITERR_CHECK_ARRAY(a) GITERR_CHECK_ALLOC((a).ptr)
+
+
+typedef git_array_t(void) git_array_generic_t;
+
+/* use a generic array for growth so this can return the new item */
+GIT_INLINE(void *) git_array_grow(git_array_generic_t *a, size_t item_size)
+{
+	uint32_t new_size = (a->size < 8) ? 8 : a->asize * 3 / 2;
+	void *new_array = git__realloc(a->ptr, new_size * item_size);
+	if (!new_array) {
+		git_array_clear(*a);
+		return NULL;
+	} else {
+		a->ptr = new_array; a->asize = new_size; a->size++;
+		return (((char *)a->ptr) + (a->size - 1) * item_size);
+	}
+}
+
+#define git_array_alloc(a) \
+	((a).size >= (a).asize) ? \
+	git_array_grow((git_array_generic_t *)&(a), sizeof(*(a).ptr)) :	\
+	(a).ptr ? &(a).ptr[(a).size++] : NULL
+
+#define git_array_last(a) ((a).size ? &(a).ptr[(a).size - 1] : NULL)
+
+#define git_array_get(a, i) (((i) < (a).size) ? &(a).ptr[(i)] : NULL)
+
+#define git_array_size(a) (a).size
+
+#endif