fix search/replace misbehaviors for good (I hope)

git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@1598 35c25a1d-7b9e-4130-9fde-d3aeb78583b8

ChangeLog

@@ -32,11 +32,12 @@ CVS code -
 	- Allow WHEREIS_NEXT_KEY to be used in view mode. (DLR)
 - search.c:
   findnextstr(), do_replace_loop()
-	- Fix potential infinite loops when doing certain forward regex
+	- Fix potential infinite loops and other misbehavior when doing
-	  replacements, where we end up either perpetually adding to the
+	  certain zero-length regex replacements ("^", "$", and "^$").
-	  end of one line (e. g. replace "$" with anything non-blank) or
+	  Add a no_sameline parameter to findnextstr(), and set it in
-	  not moving at all (e. g. replace "^" or "^$" with anything
+	  the calls in do_replace_loop() when such regexes are found, so
-	  blank). (DLR; found by Mike Frysinger and DLR)
+	  that such regexes are only found once per line. (DLR; found by
+	  Mike Frysinger and DLR)
 - winio.c:
   get_accepted_kbinput()
 	- Translate Ctrl-8 into NANO_DELETE_KEY, since it apparently is

src/proto.h

@@ -363,7 +363,7 @@ int search_init(int replacing);
 int is_whole_word(int curr_pos, const char *datastr, const char *searchword);
 filestruct *findnextstr(int quiet, int bracket_mode,
 			const filestruct *begin, int beginx,
-			const char *needle, int no_same_loc);
+			const char *needle, int no_sameline);
 int do_search(void);
 int do_research(void);
 void replace_abort(void);

src/search.c

@@ -247,7 +247,7 @@ int is_whole_word(int curr_pos, const char *datastr, const char *searchword)
 
 filestruct *findnextstr(int quiet, int bracket_mode,
 			const filestruct *begin, int beginx,
-			const char *needle, int no_same_loc)
+			const char *needle, int no_sameline)
 {
     filestruct *fileptr = current;
     const char *searchstr, *rev_start = NULL, *found = NULL;
@@ -266,11 +266,11 @@ filestruct *findnextstr(int quiet, int bracket_mode,
 	searchstr = &fileptr->data[current_x_find];
 
 	/* Look for needle in searchstr.  Keep going until we find it
-	 * and, if no_same_loc is set, until it isn't the one at
+	 * and, if no_sameline is set, until it isn't on the current
-	 * current[current_x].  If we don't find it, we'll end up at
+	 * line.  If we don't find it, we'll end up at
-	 * current[current_x] regardless of whether no_same_loc is
+	 * current[current_x] regardless of whether no_sameline is
 	 * set. */
-	while ((found = strstrwrapper(searchstr, needle, rev_start, current_x_find)) == NULL || (no_same_loc && fileptr == current && current_x_find == current_x)) {
+	while ((found = strstrwrapper(searchstr, needle, rev_start, current_x_find)) == NULL || (no_sameline && fileptr == current)) {
 
 	    /* finished processing file, get out */
 	    if (search_last_line) {
@@ -325,11 +325,11 @@ filestruct *findnextstr(int quiet, int bracket_mode,
 	searchstr = fileptr->data;
 
 	/* Look for needle in searchstr.  Keep going until we find it
-	 * and, if no_same_loc is set, until it isn't the one at
+	 * and, if no_sameline is set, until it isn't on the current
-	 * current[current_x].  If we don't find it, we'll end up at
+	 * line.  If we don't find it, we'll end up at
-	 * current[current_x] regardless of whether no_same_loc is
+	 * current[current_x] regardless of whether no_sameline is
 	 * set. */
-	while ((found = strstrwrapper(searchstr, needle, rev_start, current_x_find)) == NULL || (no_same_loc && fileptr == current && current_x_find == current_x)) {
+	while ((found = strstrwrapper(searchstr, needle, rev_start, current_x_find)) == NULL || (no_sameline && fileptr == current)) {
 
 	    /* finished processing file, get out */
 	    if (search_last_line) {
@@ -618,8 +618,8 @@ int do_replace_loop(const char *prevanswer, const filestruct *begin,
 {
     int replaceall = 0, numreplaced = -1;
 #ifdef HAVE_REGEX_H
-    /* The special case regex flags. */
+    /* The starting-line match and zero-length regex flags. */
-    int old_bol = 0, old_eol = 0;
+    int beginline = 0, caretdollar = 0;
 #endif
     filestruct *fileptr = NULL;
     char *copy;
@@ -646,37 +646,35 @@ int do_replace_loop(const char *prevanswer, const filestruct *begin,
     while (1) {
 	size_t match_len;
 
-#ifdef HAVE_REGEX_H
-	/* Check the special case regex flags.  If the last (forward,
-	 * zero-length) regex replace left us at the beginning or end of
-	 * the line as it was before replacement, move to the beginning
-	 * or end of the line as it is now. */
-	if (old_bol)
-	    current_x = 0;
-	if (old_eol)
-	    current_x = strlen(current->data);
-#endif
-
 	/* Sweet optimization by Rocco here. */
 	fileptr = findnextstr(fileptr || replaceall || search_last_line,
 		FALSE, begin, *beginx, prevanswer,
 #ifdef HAVE_REGEX_H
-		old_bol || old_eol
+		/* We should find a zero-length regex only once per
+		 * line.  If the caretdollar flag is set, it means that
+		 * the last search found one on the beginning line, so we
+		 * should skip over the beginning line when doing this
+		 * search. */
+		caretdollar
 #else
 		0
 #endif
 		);
 
 #ifdef HAVE_REGEX_H
-	/* If either of the special case regex flags are set and we're
+	/* If the caretdollar flag is set, we've found a match on the
-	 * back where we started, it means we've wrapped around, so
+	 * beginning line already, and we're still on the beginning line
+	 * after the search, it means that we've wrapped around, so
 	 * we're done. */
-	if ((old_bol || old_eol) && fileptr == begin && current_x == *beginx)
+	if (caretdollar && beginline && fileptr == begin)
 	    fileptr = NULL;
-	/* Otherwise, reset the flags and continue. */
+	/* Otherwise, set the beginline flag if we've found a match on
+	 * the beginning line, reset the caretdollar flag, and
+	 * continue. */
 	else {
-	    old_bol = 0;
+	    if (fileptr == begin)
-	    old_eol = 0;
+		beginline = 1;
+	    caretdollar = 0;
 	}
 #endif
 
@@ -720,6 +718,13 @@ int do_replace_loop(const char *prevanswer, const filestruct *begin,
 	    curs_set(1);
 	}
 
+#ifdef HAVE_REGEX_H
+	/* Set the caretdollar flag if we're doing a zero-length regex
+	 * replace (such as "^", "$", or "^$"). */
+	if (ISSET(USE_REGEXP) && match_len == 0)
+	    caretdollar = 1;
+#endif
+
 	if (*i > 0 || replaceall) {	/* Yes, replace it!!!! */
 	    long length_change;
 	    size_t match_len;
@@ -763,24 +768,9 @@ int do_replace_loop(const char *prevanswer, const filestruct *begin,
 	     * text, so searching will resume after the replacement
 	     * text.  Note that current_x might be set to -1 here. */
 #ifndef NANO_SMALL
-	    if (!ISSET(REVERSE_SEARCH)) {
+	    if (!ISSET(REVERSE_SEARCH))
-#endif
-#ifdef HAVE_REGEX_H
-		/* Set the special case regex flags if we're at the
-		 * beginning or end of the line before a (forward,
-		 * zero-length) regex replace.  Note that they can both
-		 * be set if we're replacing the magicline. */
-		if (ISSET(USE_REGEXP) && match_len == 0) {
-		    if (current_x <= 0)
-			old_bol = 1;
-		    if (current_x == strlen(current->data))
-			old_eol = 1;
-		}
 #endif
 		current_x += match_len + length_change - 1;
-#ifndef NANO_SMALL
-	    }
-#endif
 
 	    /* Cleanup. */
 	    totsize += length_change;