1 files changed, 64 insertions, 0 deletions
diff --git a/sys/fmtio/ctocc.x b/sys/fmtio/ctocc.x
new file mode 100644
index 00000000..b2f4197a
--- /dev/null
+++ b/sys/fmtio/ctocc.x
@@ -0,0 +1,64 @@
+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	<ctype.h>
+
+define	OCTAL		8
+
+# CTOCC -- Convert a character into a printable character constant.
+# Printable characters are output as is.  The standard control characters
+# (newline, tab, etc.) are output as escape sequences (\n, \t, etc.).
+# Other control characters are output in the form '^X'.  Characters which
+# are neither printable nor standard control characters are output as
+# octal constants of the form '\DDD'.  Note that the ouput string is not
+# enclosed in ticks ('\n', etc.), because the generated character constant
+# might appear in a quoted string (or someplace other than an explicit
+# character constant).
+
+int procedure ctocc (ch, outstr, maxch)
+
+char	ch			# character to be output
+char	outstr[ARB]		# output string
+int	maxch			# max chars out
+
+int	op, n
+int	stridx()
+define	output 	{outstr[op]=$1;op=op+1;if(op>maxch)goto overflow_}
+define	overflow_ 99
+include	"escchars.inc"
+
+begin
+	op = 1
+
+	if (maxch > 0) {
+	    if (IS_PRINT(ch)) {				# output char as is
+		output (ch)
+	    } else if (IS_CNTRL (ch)) {
+		n = stridx (ch, mapped_chars)
+		if (n > 0) {				# '\c'
+		    output ('\\')
+		    output (escape_chars[n])
+		} else {
+		    output ('^')			# control chars
+		    output (ch + 'A' - 1)
+		}
+
+	    } else {					# '\nnn' 
+		# Always output 3 digits so that strings like \0405 (a blank
+		# followed by a `5') can be interpreted during the reverse
+		# encoding operation.
+
+		output ('\\')
+		output (TO_DIGIT (mod (ch / 0100B, 010B)))
+		output (TO_DIGIT (mod (ch / 0010B, 010B)))
+		output (TO_DIGIT (mod (ch / 0001B, 010B)))
+	    }
+	}
+
+	outstr[op] = EOS
+	return (op-1)
+
+overflow_
+	outstr[1] = '?'					# no room, print '?'
+	outstr[2] = EOS
+	return (1)
+end