move sstrdup, scalloc, smalloc, srealloc to libi3, improve error messages

libi3/safewrappers.c

@@ -0,0 +1,47 @@
+/*
+ * vim:ts=4:sw=4:expandtab
+ *
+ * i3 - an improved dynamic tiling window manager
+ *
+ * © 2009-2011 Michael Stapelberg and contributors
+ *
+ * See file LICENSE for license information.
+ *
+ */
+#include <string.h>
+#include <stdlib.h>
+#include <err.h>
+
+
+/*
+ * The s* functions (safe) are wrappers around malloc, strdup, …, which exits if one of
+ * the called functions returns NULL, meaning that there is no more memory available
+ *
+ */
+void *smalloc(size_t size) {
+    void *result = malloc(size);
+    if (result == NULL)
+        err(EXIT_FAILURE, "malloc(%zd)", size);
+    return result;
+}
+
+void *scalloc(size_t size) {
+    void *result = calloc(size, 1);
+    if (result == NULL)
+        err(EXIT_FAILURE, "calloc(%zd)", size);
+    return result;
+}
+
+void *srealloc(void *ptr, size_t size) {
+    void *result = realloc(ptr, size);
+    if (result == NULL && size > 0)
+        err(EXIT_FAILURE, "realloc(%zd)", size);
+    return result;
+}
+
+char *sstrdup(const char *str) {
+    char *result = strdup(str);
+    if (result == NULL)
+        err(EXIT_FAILURE, "strdup()");
+    return result;
+}