From 775f00734828229ef2eca0ad8b84f36a5d70427c Mon Sep 17 00:00:00 2001
From: Benno Schulenberg <bensberg@justemail.net>
Date: Sat, 21 Jan 2017 18:18:34 +0100
Subject: [PATCH] tweaks: use a cheaper way to detect an end-of-line

There is no need to compute the line length: just avoid overstepping
the terminating NUL byte when being forced to advance the index.
---
 src/color.c | 13 +++++++------
 src/winio.c | 18 ++++++------------
 2 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/src/color.c b/src/color.c
index e68f6203..7c0fa1b6 100644
--- a/src/color.c
+++ b/src/color.c
@@ -414,7 +414,6 @@ void precalc_multicolorinfo(void)
 
 	for (line = openfile->fileage; line != NULL; line = line->next) {
 	    int index = 0;
-	    int linelen = strlen(line->data);
 
 	    alloc_multidata_if_needed(line);
 	    /* Assume nothing applies until proven otherwise below. */
@@ -424,11 +423,9 @@ void precalc_multicolorinfo(void)
 	     * found, mark all the lines that are affected. */
 	    while (regexec(ink->start, line->data + index, 1,
 			&startmatch, (index == 0) ? 0 : REG_NOTBOL) == 0) {
+		/* Begin looking for an end match after the start match. */
 		index += startmatch.rm_eo;
 
-		if (index > linelen)
-		    break;
-
 		/* If there is an end match on this line, mark the line, but
 		 * continue looking for other starts after it. */
 		if (regexec(ink->end, line->data + index, 1,
@@ -437,8 +434,12 @@ void precalc_multicolorinfo(void)
 		    index += endmatch.rm_eo;
 		    /* If both start and end are mere anchors, step ahead. */
 		    if (startmatch.rm_so == startmatch.rm_eo &&
-				endmatch.rm_so == endmatch.rm_eo)
-			index += 1;
+				endmatch.rm_so == endmatch.rm_eo) {
+			/* When at end-of-line, we're done. */
+			if (line->data[index] == '\0')
+			    break;
+			index = move_mbright(line->data, index);
+		    }
 		    continue;
 		}
 
diff --git a/src/winio.c b/src/winio.c
index 1083fffa..073ad05c 100644
--- a/src/winio.c
+++ b/src/winio.c
@@ -2419,8 +2419,6 @@ void edit_draw(filestruct *fileptr, const char *converted,
 		/* The line that matches 'end'. */
 	    regmatch_t startmatch, endmatch;
 		/* The match positions of the start and end regexes. */
-	    int linelen;
-		/* The length of the line we are currently looking at. */
 
 	    /* First see if the multidata was maybe already calculated. */
 	    if (fileptr->multidata[varnish->id] == CNONE)
@@ -2476,8 +2474,6 @@ void edit_draw(filestruct *fileptr, const char *converted,
 			start_line->multidata[varnish->id] == CSTARTENDHERE))
 		goto step_two;
 
-	    linelen = strlen(start_line->data);
-
 	    /* Now start_line is the first line before fileptr containing
 	     * a start match.  Is there a start on that line not followed
 	     * by an end on that line? */
@@ -2486,9 +2482,9 @@ void edit_draw(filestruct *fileptr, const char *converted,
 		index += startmatch.rm_eo;
 		/* If the start match is of length zero, step ahead. */
 		if (startmatch.rm_so == startmatch.rm_eo) {
-		    index = move_mbright(start_line->data, index);
-		    if (index > linelen)
+		    if (start_line->data[index] == '\0')
 			break;
+		    index = move_mbright(start_line->data, index);
 		}
 		/* If there is no end after this last start, good. */
 		if (regexec(varnish->end, start_line->data + index,
@@ -2498,9 +2494,9 @@ void edit_draw(filestruct *fileptr, const char *converted,
 		index += endmatch.rm_eo;
 		/* If the end match is of length zero, step ahead. */
 		if (endmatch.rm_so == endmatch.rm_eo) {
-		    index = move_mbright(start_line->data, index);
-		    if (index > linelen)
+		    if (start_line->data[index] == '\0')
 			break;
+		    index = move_mbright(start_line->data, index);
 		}
 		/* If there is no later start on this line, next step. */
 		if (regexec(varnish->start, start_line->data + index,
@@ -2545,8 +2541,6 @@ void edit_draw(filestruct *fileptr, const char *converted,
 	     * looking only after an end match, if there is one. */
 	    index = (paintlen == 0) ? 0 : endmatch.rm_eo;
 
-	    linelen = strlen(fileptr->data);
-
 	    while (regexec(varnish->start, fileptr->data + index,
 				1, &startmatch, (index == 0) ?
 				0 : REG_NOTBOL) == 0) {
@@ -2586,9 +2580,9 @@ void edit_draw(filestruct *fileptr, const char *converted,
 		    index = endmatch.rm_eo;
 		    /* If the end match is of length zero, step ahead. */
 		    if (endmatch.rm_so == endmatch.rm_eo) {
-			index = move_mbright(fileptr->data, index);
-			if (index > linelen)
+			if (fileptr->data[index] == '\0')
 			    break;
+			index = move_mbright(fileptr->data, index);
 		    }
 		    continue;
 		}