vi: handle autoindent in 'cc' command

When the 'cc' command is invoked with autoindent enabled it
should use the indent of the first line being changed.

The size of the indent has to be established before char_insert()
is called as the lines being changed are deleted.  Introduce a
new global variable, newindent, to handle this.  The indentcol
global is now effectively a static variable in char_insert().

function                                             old     new   delta
do_cmd                                              4247    4308     +61
vi_main                                              416     422      +6
char_insert                                          891     875     -16
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/1 up/down: 67/-16)             Total: 51 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

editors/vi.c

@@ -380,7 +380,9 @@ struct globals {
 	char *last_search_pattern; // last pattern from a '/' or '?' search
 #endif
 #if ENABLE_FEATURE_VI_SETOPTS
-	int indentcol;		// column of recently autoindent, 0 or -1
+	int char_insert__indentcol;		// column of recent autoindent or 0
+	int newindent;		// autoindent value for 'O'/'cc' commands
+						// or -1 to use indent from previous line
 #endif
 	smallint cmd_error;
 
@@ -507,7 +509,8 @@ struct globals {
 #define ioq_start               (G.ioq_start          )
 #define dotcnt                  (G.dotcnt             )
 #define last_search_pattern     (G.last_search_pattern)
-#define indentcol               (G.indentcol          )
+#define char_insert__indentcol  (G.char_insert__indentcol)
+#define newindent               (G.newindent          )
 #define cmd_error               (G.cmd_error          )
 
 #define edit_file__cur_line     (G.edit_file__cur_line)
@@ -540,10 +543,11 @@ struct globals {
 
 #define INIT_G() do { \
 	SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
-	last_modified_count = -1; \
+	last_modified_count--; \
 	/* "" but has space for 2 chars: */ \
 	IF_FEATURE_VI_SEARCH(last_search_pattern = xzalloc(2);) \
 	tabstop = 8; \
+	IF_FEATURE_VI_SETOPTS(newindent--;) \
 } while (0)
 
 #if ENABLE_FEATURE_VI_CRASHME
@@ -2113,6 +2117,7 @@ static size_t indent_len(char *p)
 static char *char_insert(char *p, char c, int undo) // insert the char c at 'p'
 {
 #if ENABLE_FEATURE_VI_SETOPTS
+# define indentcol char_insert__indentcol
 	size_t len;
 	int col, ntab, nspc;
 #endif
@@ -2141,7 +2146,8 @@ static char *char_insert(char *p, char c, int undo) // insert the char c at 'p'
 #if ENABLE_FEATURE_VI_SETOPTS
 		if (autoindent) {
 			len = indent_len(bol);
-			if (len && get_column(bol + len) == indentcol && bol[len] == '\n') {
+			col = get_column(bol + len);
+			if (len && col == indentcol && bol[len] == '\n') {
 				// remove autoindent from otherwise empty line
 				text_hole_delete(bol, bol + len - 1, undo);
 				p = bol;
@@ -2210,26 +2216,30 @@ static char *char_insert(char *p, char c, int undo) // insert the char c at 'p'
 			showmatching(p - 1);
 		}
 		if (autoindent && c == '\n') {	// auto indent the new line
-			// use indent of current/previous line
-			bol = indentcol < 0 ? p : prev_line(p);
-			len = indent_len(bol);
-			col = get_column(bol + len);
-
-			if (len && col == indentcol) {
-				// previous line was empty except for autoindent
-				// move the indent to the current line
-				memmove(bol + 1, bol, len);
-				*bol = '\n';
-				return p;
+			if (newindent < 0) {
+				// use indent of previous line
+				bol = prev_line(p);
+				len = indent_len(bol);
+				col = get_column(bol + len);
+
+				if (len && col == indentcol) {
+					// previous line was empty except for autoindent
+					// move the indent to the current line
+					memmove(bol + 1, bol, len);
+					*bol = '\n';
+					return p;
+				}
+			} else {
+				// for 'O'/'cc' commands add indent before newly inserted NL
+				if (p != end - 1)	// but not for 'cc' at EOF
+					p--;
+				col = newindent;
 			}
 
-			if (indentcol < 0)
-				p--;	// open above, indent before newly inserted NL
-
-			if (len) {
+			if (col) {
 				// only record indent if in insert/replace mode or for
-				// the 'o'/'O' commands, which are switched to insert
-				// mode early.
+				// the 'o'/'O'/'cc' commands, which are switched to
+				// insert mode early.
 				indentcol = cmd_mode != 0 ? col : 0;
 				if (expandtab) {
 					ntab = 0;
@@ -2252,6 +2262,7 @@ static char *char_insert(char *p, char c, int undo) // insert the char c at 'p'
 	}
 #if ENABLE_FEATURE_VI_SETOPTS
 	indentcol = 0;
+# undef indentcol
 #endif
 	return p;
 }
@@ -4220,6 +4231,9 @@ static void do_cmd(int c)
 	case 'i':			// i- insert before current char
 	case KEYCODE_INSERT:	// Cursor Key Insert
  dc_i:
+#if ENABLE_FEATURE_VI_SETOPTS
+		newindent = -1;
+#endif
 		cmd_mode = 1;	// start inserting
 		undo_queue_commit();	// commit queue when cmd_mode changes
 		break;
@@ -4262,7 +4276,8 @@ static void do_cmd(int c)
 	case 'O':			// O- open an empty line above
 		dot_begin();
 #if ENABLE_FEATURE_VI_SETOPTS
-		indentcol = -1;
+		// special case: use indent of current line
+		newindent = get_column(dot + indent_len(dot));
 #endif
 		goto dc3;
 	case 'o':			// o- open an empty line below
@@ -4385,14 +4400,22 @@ static void do_cmd(int c)
 		if (buftype == WHOLE) {
 			save_dot = p;	// final cursor position is start of range
 			p = begin_line(p);
+#if ENABLE_FEATURE_VI_SETOPTS
+			if (c == 'c')	// special case: use indent of current line
+				newindent = get_column(p + indent_len(p));
+#endif
 			q = end_line(q);
 		}
 		dot = yank_delete(p, q, buftype, yf, ALLOW_UNDO);	// delete word
 		if (buftype == WHOLE) {
 			if (c == 'c') {
+#if ENABLE_FEATURE_VI_SETOPTS
+				cmd_mode = 1;	// switch to insert mode early
+#endif
 				dot = char_insert(dot, '\n', ALLOW_UNDO_CHAIN);
-				// on the last line of file don't move to prev line
-				if (dot != (end-1)) {
+				// on the last line of file don't move to prev line,
+				// handled in char_insert() if autoindent is enabled
+				if (dot != (end-1) && !autoindent) {
 					dot_prev();
 				}
 			} else if (c == 'd') {