-/* HasPrefix returns true if non-NULL s starts with non-NULL prefix. */
-bool HasPrefix(const char *s, const char *prefix)
+/* truncpy copies at most size - 1 chars from non-NULL src to non-NULL,
+ * non-overlapping, dst, and ensures dst is NUL terminated. If size is
+ * zero then it aborts as dst cannot be NUL terminated.
+ *
+ * It's to be used when truncation is intended and correct, e.g.
+ * reporting a possibly very long external string back to the user. One
+ * of its advantages over strncpy(3) is it doesn't pad in the common
+ * case of no truncation. */
+void trunccpy(char *dst, const char *src, size_t size)
+{
+ if (!size) {
+ inform("trunccpy: zero-length destination: \"%.20s\"",
+ src ? src : "null");
+ abort();
+ }
+
+ if (strnlen(src, size) < size) {
+ strcpy(dst, src);
+ } else {
+ memcpy(dst, src, size - 1);
+ dst[size - 1] = '\0';
+ }
+}
+
+
+/* has_prefix returns true if non-NULL s starts with non-NULL prefix. */
+bool has_prefix(const char *s, const char *prefix)