1 files changed, 124 insertions, 0 deletions
diff --git a/unix/os/zfacss.c b/unix/os/zfacss.c
new file mode 100644
index 00000000..f6624698
--- /dev/null
+++ b/unix/os/zfacss.c
@@ -0,0 +1,124 @@
+/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+ */
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <ctype.h>
+
+#define	import_kernel
+#define	import_knames
+#define import_spp
+#include <iraf.h>
+
+#define	SZ_TESTBLOCK	1024		/* for TEXT/BINARY heuristic	*/
+#define	MAX_LINELEN	256		/* when looking for newlines	*/
+#define	R		04		/* UNIX access() codes		*/
+#define W		02
+#define ctrlcode(c)	((c) >= '\007' && (c) <= '\017')
+
+
+/* ZFACSS -- Try to determine if FILE is accessible in the indicated MODE.
+ * If file is accessible for reading and TYPE is given as TEXT_FILE,
+ * look at the first block of data to see if it is legal text data.
+ * ACCESS(file,0,0) merely checks that the file exists.  Any file is a
+ * legal binary file.
+ */
+int
+ZFACSS (
+  PKCHAR  *fname,
+  XINT	  *mode, 
+  XINT 	  *type,
+  XINT 	  *status
+)
+{
+	static	char modebits[] = { 0, R, R|W, W, R|W };
+	register char	*ip, ch;
+	register int	n;
+	char	buf[SZ_TESTBLOCK];
+	int	fd, acmode, accessible, nchars, newline_seen;
+	struct	stat fi;
+
+	/* Null filename? */
+	if (*(char *)fname == EOS) {
+	    *status = NO;
+	    return (NO);
+	}
+
+	/* Map IRAF access mode into UNIX access mode.
+	 */
+	if (*mode >= READ_ONLY && *mode <= APPEND)
+	    acmode = modebits[*mode];
+	else if (*mode == 0 && *type != 0)
+	    acmode = R;
+	else
+	    acmode = 0;
+
+	/* Is file accessible with the given mode.
+	 */
+	accessible = (access ((char *)fname, acmode) == 0);
+
+	if (accessible && *type == DIRECTORY_FILE) {
+	    stat ((char *)fname, &fi);
+	    if (fi.st_mode & S_IFDIR)
+		*status = YES;
+	    else
+		*status = NO;
+	    return (*status);
+
+	} else if (!accessible && *type == SYMLINK_FILE) {
+	    lstat ((char *)fname, &fi);
+	    if (fi.st_mode & S_IFLNK)
+		*status = YES;
+	    else
+		*status = NO;
+
+	    return (*status);
+	}
+
+	/* If we have to check the file type (text or binary), then we must
+	 * actually look at some file data since UNIX does not discriminate
+	 * between text and binary files.  NOTE that this heuristic is not
+	 * completely reliable and can fail, although in practice it does
+	 * very well.
+	 */
+	if (accessible && (acmode & R) && *type != 0) {
+	    stat ((char *)fname, &fi);
+
+	    /* Do NOT read from a special device (may block) */
+	    if ((fi.st_mode & S_IFMT) & S_IFREG) {
+		/* If we are testing for a text file the portion of the file
+		 * tested must consist of only printable ascii characters or
+		 * whitespace, with occasional newline line delimiters.
+		 * Control characters embedded in the text will cause the
+		 * heuristic to fail.  We require newlines to be present in
+		 * the text to disinguish the case of a binary file containing
+		 * only ascii data, e.g., a cardimage file.
+		 */
+		fd = open ((char *)fname, 0);
+		if (fd >= 0 && (nchars = read (fd, buf, SZ_TESTBLOCK)) > 0) {
+		    ip = buf;
+		    for (n=nchars, newline_seen=0;  --n >= 0;  ) {
+			ch = *ip++;
+			if (ch == '\n')
+			    newline_seen++;
+			else if (!isprint(ch) && !isspace(ch) && !ctrlcode(ch))
+			    break;
+		    }
+
+		    if (*type == TEXT_FILE) {
+			if (n >= 0 || (nchars > MAX_LINELEN && !newline_seen))
+			    accessible = NO;
+		    } else if (*type == BINARY_FILE && n < 0)
+			accessible = NO;
+		    close (fd);
+		}
+	    } else if (fi.st_mode & S_IFCHR && *type != TEXT_FILE)
+		accessible = NO;
+	}
+		
+	(*status) = accessible;
+
+	return (*status);
+}