1 files changed, 18 insertions, 0 deletions
diff --git a/src/libstddjb/bitarray_not.c b/src/libstddjb/bitarray_not.c
new file mode 100644
index 0000000..4bd95ad
--- /dev/null
+++ b/src/libstddjb/bitarray_not.c
@@ -0,0 +1,18 @@
+/* ISC license. */
+
+#include <skalibs/bitarray.h>
+
+void bitarray_not (register unsigned char *s, register unsigned int a, register unsigned int b)
+{
+  if (!b) return ;
+  b += a ;
+  if ((a >> 3) == ((b-1) >> 3))
+    s[a>>3] ^= ((1 << (a & 7)) - 1) ^ ((a << (b & 7)) - 1) ;
+  else
+  {
+    register unsigned int i = (a>>3) + 1 ;
+    s[a>>3] ^= ~((1 << (a & 7)) - 1) ;
+    for (; i < (b>>3) - 1 ; i++) s[i] = ~s[i] ;
+    s[b>>3] ^= (1 << (b & 7)) - 1 ;
+  }
+}