MFC r317051: bsdgrep: remove output separators between overlapping segments

Make bsdgrep more sensitive to context overlaps.  If it's printing
context that either overlaps or is immediately adjacent to another bit
of context, don't print a separator.

- Non-overlapping segments no longer have two separators between them

- Overlapping segments no longer have separators between them with
  overlapping sections repeated

Approved by:	emaste (mentor, blanket MFC)

1 files changed, 27 insertions, 6 deletions

diff --git a/usr.bin/grep/util.c b/usr.bin/grep/util.c
index 4ab7b06..437a264 100644
--- a/usr.bin/grep/util.c
+++ b/usr.bin/grep/util.c
@@ -55,6 +55,9 @@ __FBSDID("$FreeBSD$");
 static int	 linesqueued;
 static int	 procline(struct str *l, int);
 
+static int	 lasta;
+static bool	 ctxover;
+
 bool
 file_matching(const char *fname)
 {
@@ -204,8 +207,10 @@ procfile(const char *fn)
 	strcpy(ln.file, fn);
 	ln.line_no = 0;
 	ln.len = 0;
+	ctxover = false;
 	linesqueued = 0;
 	tail = 0;
+	lasta = 0;
 	ln.off = -1;
 
 	for (c = 0;  c == 0 || !(lflag || qflag); ) {
@@ -227,10 +232,24 @@ procfile(const char *fn)
 			free(f);
 			return (0);
 		}
-		/* Process the file line-by-line */
+
+		/* Process the file line-by-line, enqueue non-matching lines */
 		if ((t = procline(&ln, f->binary)) == 0 && Bflag > 0) {
-			enqueue(&ln);
-			linesqueued++;
+			/* Except don't enqueue lines that appear in -A ctx */
+			if (ln.line_no == 0 || lasta != ln.line_no) {
+				/* queue is maxed to Bflag number of lines */
+				enqueue(&ln);
+				linesqueued++;
+				ctxover = false;
+			} else {
+				/*
+				 * Indicate to procline() that we have ctx
+				 * overlap and make sure queue is empty.
+				 */
+				if (!ctxover)
+					clearqueue();
+				ctxover = true;
+			}
 		}
 		c += t;
 		if (mflag && mcount <= 0)
@@ -385,17 +404,19 @@ procline(struct str *l, int nottext)
 	/* Dealing with the context */
 	if ((tail || c) && !cflag && !qflag && !lflag && !Lflag) {
 		if (c) {
-			if (!first && !prev && !tail && Aflag)
+			if (!first && !prev && !tail && (Bflag || Aflag) &&
+			    !ctxover)
 				printf("--\n");
 			tail = Aflag;
 			if (Bflag > 0) {
-				if (!first && !prev)
-					printf("--\n");
 				printqueue();
+				ctxover = false;
 			}
 			linesqueued = 0;
 			printline(l, ':', matches, m);
 		} else {
+			/* Print -A lines following matches */
+			lasta = l->line_no;
 			printline(l, '-', matches, m);
 			tail--;
 		}