1 files changed, 63 insertions, 0 deletions
diff --git a/unix/os/zfnbrk.c b/unix/os/zfnbrk.c
new file mode 100644
index 00000000..33552976
--- /dev/null
+++ b/unix/os/zfnbrk.c
@@ -0,0 +1,63 @@
+/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+ */
+
+#include <stdio.h>
+#include <ctype.h>
+#define	import_spp
+#define	import_kernel
+#define	import_knames
+#include <iraf.h>
+
+/* ZFNBRK -- Determine the offsets of the components of a virtual file name:
+ *
+ * 	"ldir$subdir/root.extn"
+ * 
+ * Both logical and OS dependent directory prefixes should be successfully
+ * recognized, hence this routine is potentially machine dependent.  This
+ * procedure appears to work correctly for AOS, VMS, and UNIX filenames, as well
+ * as IRAF virtual filenames.
+ * 
+ * The legal characters in an IRAF VFN are [a-zA-Z0-9_.].  The character '.',
+ * if present, separates the root file name from the extension.  If multiple
+ * period delimited fields are present, the final field is taken to be the
+ * extension, and the previous fields are included in the root name.  Other
+ * characters may or may not be permitted in filenames depending upon the
+ * restrictions of the host system.
+ * 
+ * The end of the logical directory prefix, if present, is marked by the index
+ * of the last non-VFN character encountered.
+ */
+int
+ZFNBRK (
+  XCHAR	*vfn,			/* VFN to be scanned			*/
+  XINT	*uroot_offset,		/* index of first char in root, or 0	*/
+  XINT	*uextn_offset		/* index of first char in extn, or 0	*/
+)
+{
+	register int	ch;
+	register XCHAR	*ip;
+	XCHAR	*root_offset, *extn_offset;
+
+	root_offset = vfn;
+	extn_offset = NULL;
+
+	for (ip=vfn;  *ip != EOS;  ip++) {
+	    ch = *ip;
+	    if (ch == '\\' && *(ip+1) != EOS)
+		ip++;
+	    else if (ch == '.')
+		extn_offset = ip;		/* possibly start of extn */
+	    else if (ch == '$' || ch == '/' || ch == ':' || ch == ']')
+		root_offset = ip+1;		/* part of logical name */
+	}
+
+	if (extn_offset <= root_offset)
+	    extn_offset = ip;			/* no extension */
+	else if (*(extn_offset+1) == EOS)
+	    extn_offset = ip;			/* no extn if "root." */
+
+	*uroot_offset = root_offset - vfn + 1;
+	*uextn_offset = extn_offset - vfn + 1;
+
+	return (XOK);
+}