Add the -t option, which allows tab stop positions to be specified similarly

to the way expand(1) allows. This brings unexpand(1) up to SUSv3 conformance,
and it now passes all relevant parts of the GNU textutils test suite.

PR:		35621
Reviewed by:	mike

1 files changed, 118 insertions, 51 deletions

diff --git a/usr.bin/unexpand/unexpand.c b/usr.bin/unexpand/unexpand.c
index 51b8d3b..1df6c46 100644
--- a/usr.bin/unexpand/unexpand.c
+++ b/usr.bin/unexpand/unexpand.c
@@ -49,45 +49,53 @@ static const char sccsid[] = "@(#)unexpand.c	8.1 (Berkeley) 6/6/93";
  * unexpand - put tabs into a file replacing blanks
  */
 #include <err.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
-char	genbuf[BUFSIZ];
-char	linebuf[BUFSIZ];
 int	all;
+int	nstops;
+int	tabstops[100];
 
+static void getstops(const char *);
 static void usage(void);
-void tabify(char);
+static void tabify(void);
 
 int
 main(argc, argv)
 	int argc;
 	char *argv[];
 {
-	register char *cp;
+	int ch;
 
-	argc--, argv++;
-	if (argc > 0 && argv[0][0] == '-') {
-		if (strcmp(argv[0], "-a") != 0)
+	nstops = 1;
+	tabstops[0] = 8;
+	while ((ch = getopt(argc, argv, "at:")) != -1) {
+		switch (ch) {
+		case 'a':	/* Un-expand all spaces, not just leading. */
+			all = 1;
+			break;
+		case 't':	/* Specify tab list, implies -a. */
+			getstops(optarg);
+			all = 1;
+			break;
+		default:
 			usage();
-		all++;
-		argc--, argv++;
+			/*NOTREACHED*/
+		}
 	}
+	argc -= optind;
+	argv += optind;
+
 	do {
 		if (argc > 0) {
 			if (freopen(argv[0], "r", stdin) == NULL)
 				err(1, "%s", argv[0]);
 			argc--, argv++;
 		}
-		while (fgets(genbuf, BUFSIZ, stdin) != NULL) {
-			for (cp = linebuf; *cp; cp++)
-				continue;
-			if (cp > linebuf)
-				cp[-1] = 0;
-			tabify(all);
-			printf("%s", linebuf);
-		}
+		tabify();
 	} while (argc > 0);
 	exit(0);
 }
@@ -95,52 +103,111 @@ main(argc, argv)
 static void
 usage()
 {
-	fprintf(stderr, "usage: unexpand [-a] file ...\n");
+	fprintf(stderr, "usage: unexpand [-a] [-t tablist] [file ...]\n");
 	exit(1);
 }
 
-void
-tabify(c)
-	char c;
+static void
+tabify()
 {
-	register char *cp, *dp;
-	register int dcol;
-	int ocol;
+	int ch, dcol, doneline, limit, n, ocol;
 
-	ocol = 0;
-	dcol = 0;
-	cp = genbuf, dp = linebuf;
-	for (;;) {
-		switch (*cp) {
-
-		case ' ':
-			dcol++;
-			break;
+	limit = nstops == 1 ? INT_MAX : tabstops[nstops - 1] - 1;
 
-		case '\t':
-			dcol += 8;
-			dcol &= ~07;
-			break;
+	doneline = ocol = dcol = 0;
+	while ((ch = getchar()) != EOF) {
+		if (ch == '\n') {
+			putchar('\n');
+			doneline = ocol = dcol = 0;
+			continue;
+		} else if (ch == ' ' && !doneline) {
+			if (++dcol >= limit)
+				doneline = 1;
+			continue;
+		} else if (ch == '\b' && dcol > 0) {
+			dcol--;
+		} else if (ch == '\t') {
+			if (nstops == 1) {
+				dcol = (1 + dcol / tabstops[0]) *
+				    tabstops[0];
+				continue;
+			} else {
+				for (n = 0; tabstops[n] - 1 < dcol &&
+				    n < nstops; n++)
+					;
+				if (n < nstops - 1 && tabstops[n] - 1 < limit) {
+					dcol = tabstops[n];
+					continue;
+				}
+				doneline = 1;
+			}
+		}
 
-		default:
-			while (((ocol + 8) &~ 07) <= dcol) {
-				if (ocol + 1 == dcol)
+		/* Output maximal number of tabs. */
+		if (nstops == 1) {
+			while (((ocol + tabstops[0]) / tabstops[0])
+			    <= (dcol / tabstops[0])) {
+				if (dcol - ocol < 2)
 					break;
-				*dp++ = '\t';
-				ocol += 8;
-				ocol &= ~07;
+				putchar('\t');
+				ocol = (1 + ocol / tabstops[0]) *
+				    tabstops[0];
 			}
-			while (ocol < dcol) {
-				*dp++ = ' ';
-				ocol++;
+		} else {
+			for (n = 0; tabstops[n] - 1 < ocol && n < nstops; n++)
+				;
+			while (ocol < dcol && n < nstops && ocol < limit) {
+				putchar('\t');
+				ocol = tabstops[n++];
 			}
-			if (*cp == 0 || c == 0) {
-				strcpy(dp, cp);
-				return;
-			}
-			*dp++ = *cp;
+		}
+
+		/* Then spaces. */
+		while (ocol < dcol && ocol < limit) {
+			putchar(' ');
+			ocol++;
+		}
+
+		if (ch != ' ' || dcol > limit) {
+			putchar(ch);
 			ocol++, dcol++;
 		}
+
+		/*
+		 * Only processing leading blanks or we've gone past the
+		 * last tab stop. Emit remainder of this line unchanged.
+		 */
+		if (!all || dcol >= limit) {
+			while ((ch = getchar()) != '\n' && ch != EOF)
+				putchar(ch);
+			if (ch == '\n')
+				ungetc(ch, stdin);
+		}
+	}
+}
+
+static void
+getstops(cp)
+	const char *cp;
+{
+	int i;
+
+	nstops = 0;
+	for (;;) {
+		i = 0;
+		while (*cp >= '0' && *cp <= '9')
+			i = i * 10 + *cp++ - '0';
+		if (i <= 0)
+			errx(1, "bad tab stop spec");
+		if (nstops > 0 && i <= tabstops[nstops-1])
+			errx(1, "bad tab stop spec");
+		if (nstops == sizeof(tabstops) / sizeof(*tabstops))
+			errx(1, "too many tab stops");
+		tabstops[nstops++] = i;
+		if (*cp == 0)
+			break;
+		if (*cp != ',' && *cp != ' ')
+			errx(1, "bad tab stop spec");
 		cp++;
 	}
 }