1 files changed, 17 insertions, 0 deletions
diff --git a/src/str_diff.c b/src/str_diff.c
new file mode 100644
index 0000000..47dff22
--- /dev/null
+++ b/src/str_diff.c
@@ -0,0 +1,17 @@
+/* Public domain. */
+
+#include "str.h"
+
+int str_diff(register const char *s,register const char *t)
+{
+  register char x;
+
+  for (;;) {
+    x = *s; if (x != *t) break; if (!x) break; ++s; ++t;
+    x = *s; if (x != *t) break; if (!x) break; ++s; ++t;
+    x = *s; if (x != *t) break; if (!x) break; ++s; ++t;
+    x = *s; if (x != *t) break; if (!x) break; ++s; ++t;
+  }
+  return ((int)(unsigned int)(unsigned char) x)
+       - ((int)(unsigned int)(unsigned char) *t);
+}