Making sure to keep advancing also when regex matches are zero-length.

This fixes Savannah bug #26977 -- a hang on start="^" end="$".


git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@5538 35c25a1d-7b9e-4130-9fde-d3aeb78583b8

ChangeLog

+2016-01-09  Benno Schulenberg  <bensberg@justemail.net>
+	* src/color.c (precalc_multicolorinfo), src/winio.c (edit_draw):
+	Make sure to keep advancing also when matches are zero-length.
+	This fixes Savannah bug #26977 reported by Tigrmesh.
+
 2016-01-07  Benno Schulenberg  <bensberg@justemail.net>
 	* src/global.c (assign_keyinfo): Delete two unneeded #ifdefs: if
 	they /could/ be false, the H and E keys would stop working.

src/color.c

@@ -527,6 +527,10 @@ void precalc_multicolorinfo(void)
 		if (regexec(tmpcolor->end, &fileptr->data[startx], 1,
 			&endmatch, (startx == 0) ? 0 : REG_NOTBOL) == 0) {
 		    startx += endmatch.rm_eo;
+		    /* Step ahead when both start and end are mere anchors. */
+		    if (startmatch.rm_so == startmatch.rm_eo &&
+				endmatch.rm_so == endmatch.rm_eo)
+			startx += 1;
 		    fileptr->multidata[tmpcolor->id] = CSTARTENDHERE;
 #ifdef DEBUG
 		    fprintf(stderr, "end found on this line\n");

src/winio.c

@@ -2611,6 +2611,9 @@ void edit_draw(filestruct *fileptr, const char *converted, int
 			    }
 			}
 			start_col = endmatch.rm_eo;
+			/* Skip over a zero-length match. */
+			if (endmatch.rm_so == endmatch.rm_eo)
+			    start_col += 1;
 		    } else {
 			/* There is no end on this line.  But we haven't yet
 			 * looked for one on later lines. */