1 files changed, 18 insertions, 0 deletions
diff --git a/src/libstddjb/case_diffs.c b/src/libstddjb/case_diffs.c
new file mode 100644
index 0000000..2731408
--- /dev/null
+++ b/src/libstddjb/case_diffs.c
@@ -0,0 +1,18 @@
+/* ISC license. */
+
+#include <skalibs/bytestr.h>
+
+int case_diffs (char const *s, char const *t)
+{
+  register unsigned char x = 1, y = 1 ;
+  unsigned char const d = 'a' - 'A' ;
+
+  while (x && (x == y))
+  {
+    x = *s++ ;
+    if (('a' <= x) && (x <= 'z')) x -= d ;
+    y = *t++ ;
+    if (('a' <= y) && (y <= 'z')) y -= d ;
+  }
+  return (int)(x - y) ;
+}