all: rework how arrays work

Instead of having a null pointer, use a dummy array which just
says the array is empty. This helps in multiple places of the code
which would otherwise need explicitly need to check first if the
array exists. This has been cause of multiple seg.faults in the
past as the array check is easily omitted.

This also removes (or fixes) all existing checks accordingly.

1 files changed, 41 insertions, 0 deletions

diff --git a/src/common.c b/src/common.c
new file mode 100644
index 0000000..3eee2fb
--- /dev/null
+++ b/src/common.c
@@ -0,0 +1,41 @@
+/* common.c - Alpine Package Keeper (APK)
+ *
+ * Copyright (C) 2010 Timo Teräs <timo.teras@iki.fi>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation. See http://www.gnu.org/ for details.
+ */
+
+#include <malloc.h>
+#include <string.h>
+#include "apk_defines.h"
+
+static int *dummy_array = 0;
+
+void *apk_array_resize(void *array, size_t new_size, size_t elem_size)
+{
+	int old_size, diff;
+	void *tmp;
+
+	if (new_size == 0) {
+		if (array != &dummy_array)
+			free(array);
+		return &dummy_array;
+	}
+
+	old_size = array ? *((int*) array) : 0;
+	diff = new_size - old_size;
+
+	if (array == &dummy_array)
+		array = NULL;
+
+	tmp = realloc(array, sizeof(int) + new_size * elem_size);
+	if (diff > 0)
+		memset(tmp + sizeof(int) + old_size * elem_size, 0,
+		       diff * elem_size);
+	*((int*) tmp) = new_size;
+
+	return tmp;
+}