Initial commit

1 files changed, 46 insertions, 0 deletions

diff --git a/sys/osb/bswap4.c b/sys/osb/bswap4.c
new file mode 100644
index 00000000..763633a5
--- /dev/null
+++ b/sys/osb/bswap4.c
@@ -0,0 +1,46 @@
+/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+ */
+
+#define	import_spp
+#define import_knames
+#include <iraf.h>
+
+/* BSWAP4 - Move bytes from array "a" to array "b", swapping the four bytes
+ * in each successive 4 byte group, i.e., 12345678 becomes 43218765.
+ * The input and output arrays may be the same but may not partially overlap.
+ */
+BSWAP4 (a, aoff, b, boff, nbytes)
+XCHAR	*a;			/* input array			*/
+XINT	*aoff;			/* first byte in input array	*/
+XCHAR	*b;			/* output array			*/
+XINT	*boff;			/* first byte in output array	*/
+XINT	*nbytes;		/* number of bytes to swap	*/
+{
+	register char	*ip, *op, *tp;
+	register int	n;
+	static	char temp[4];
+
+	tp = temp;
+	ip = (char *)a + *aoff - 1;
+	op = (char *)b + *boff - 1;
+
+	/* Swap successive four byte groups.
+	 */
+	for (n = *nbytes >> 2;  --n >= 0;  ) {
+	    *tp++ = *ip++;
+	    *tp++ = *ip++;
+	    *tp++ = *ip++;
+	    *tp++ = *ip++;
+	    *op++ = *--tp;
+	    *op++ = *--tp;
+	    *op++ = *--tp;
+	    *op++ = *--tp;
+	}
+
+	/* If there are any odd bytes left, move them to the output array.
+	 * Do not bother to swap as it is unclear how to swap a partial
+	 * group, and really incorrect if the data is not modulus 4.
+	 */
+	for (n = *nbytes & 03;  --n >= 0;  )
+	    *op++ = *ip++;
+}