From ff57ef606cfea373c507b9dffd7cc60e6e3eae43 Mon Sep 17 00:00:00 2001
From: kevans <kevans@FreeBSD.org>
Date: Wed, 16 Aug 2017 01:03:04 +0000
Subject: 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)
---
 usr.bin/grep/util.c | 33 +++++++++++++++++++++++++++------
 1 file changed, 27 insertions(+), 6 deletions(-)

(limited to 'usr.bin/grep')

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--;
 		}
-- 
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