Add array utility functions

array.c

@@ -0,0 +1,121 @@
+/*
+  chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Miroslav Lichvar  2014
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ * 
+ **********************************************************************
+
+  =======================================================================
+
+  Functions implementing an array with automatic memory allocation.
+
+  */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "array.h"
+#include "memory.h"
+
+struct ARR_Instance_Record {
+  void *data;
+  unsigned int elem_size;
+  unsigned int used;
+  unsigned int allocated;
+};
+
+ARR_Instance
+ARR_CreateInstance(unsigned int elem_size)
+{
+  ARR_Instance array;
+
+  array = MallocNew(struct ARR_Instance_Record);
+
+  array->data = NULL;
+  array->elem_size = elem_size;
+  array->used = 0;
+  array->allocated = 0;
+
+  return array;
+}
+
+void
+ARR_DestroyInstance(ARR_Instance array)
+{
+  Free(array->data);
+  Free(array);
+}
+
+static void
+realloc_array(ARR_Instance array, unsigned int min_size)
+{
+  if (array->allocated >= min_size && array->allocated <= 2 * min_size)
+    return;
+
+  if (array->allocated < min_size) {
+    while (array->allocated < min_size)
+      array->allocated = array->allocated ? 2 * array->allocated : 1;
+  } else {
+    array->allocated = min_size;
+  }
+
+  array->data = Realloc(array->data, array->elem_size * array->allocated);
+}
+
+void *
+ARR_GetNewElement(ARR_Instance array)
+{
+  array->used++;
+  realloc_array(array, array->used);
+  return ARR_GetElement(array, array->used - 1);
+}
+
+void *
+ARR_GetElement(ARR_Instance array, unsigned int index)
+{
+  assert(index < array->used);
+  return (void *)((char *)array->data + index * array->elem_size);
+}
+
+void *
+ARR_GetElements(ARR_Instance array)
+{
+  return array->data;
+}
+
+void
+ARR_AppendElement(ARR_Instance array, void *element)
+{
+  void *e;
+
+  e = ARR_GetNewElement(array);
+  memcpy(e, element, array->elem_size);
+}
+
+void
+ARR_SetSize(ARR_Instance array, unsigned int size)
+{
+  realloc_array(array, size);
+  array->used = size;
+}
+
+unsigned int
+ARR_GetSize(ARR_Instance array)
+{
+  return array->used;
+}