From 92078e5595c56ec78150448189932b22ecf3e27f Mon Sep 17 00:00:00 2001
From: Renaud Fivet <renaud.fivet@gmail.com>
Date: Fri, 20 May 2016 19:46:54 +0800
Subject: [PATCH] Check consistency of forwchar/backchar calls. Review entab
 dot movement.

---
 line.c   |  2 ++
 random.c | 17 ++++++++++-------
 window.h | 21 ++++++++++++---------
 3 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/line.c b/line.c
index f085b8c..5e39617 100644
--- a/line.c
+++ b/line.c
@@ -114,6 +114,7 @@ static unsigned utf8_revdelta( unsigned char *p, unsigned pos) {
 }
 
 boolean backchar( int f, int n) {
+	assert( f == TRUE || (f == FALSE && n == 1)) ;
 	if( n < 0)
 		return forwchar( f, -n) ;
 
@@ -147,6 +148,7 @@ boolean backchar( int f, int n) {
  * buffer. Set the flag if the line pointer for dot changes.
  */
 boolean forwchar( int f, int n) {
+	assert( f == TRUE || (f == FALSE && n == 1)) ;
 	if( n < 0)
 		return backchar( f, -n) ;
 
diff --git a/random.c b/random.c
index d0e239f..c4e9506 100644
--- a/random.c
+++ b/random.c
@@ -329,12 +329,15 @@ int detab(int f, int n)
 		/* detab the entire current line */
 		while (curwp->w_doto < llength(curwp->w_dotp)) {
 			/* if we have a tab */
-			if (lgetc(curwp->w_dotp, curwp->w_doto) == '\t') {
-				ldelchar(1, FALSE);
-				insspace( TRUE, tabwidth - curwp->w_doto % tabwidth);
-			}
+			if( curwbyte() == '\t') {
+				int size ;
 
-			forwchar(FALSE, 1);
+				ldelchar( 1, FALSE) ;
+				size = tabwidth - curwp->w_doto % tabwidth ;
+				insspace( TRUE, size) ;
+				forwchar( TRUE, size) ;
+			} else
+				forwchar( FALSE, 1) ;
 		}
 
 		/* advance/or back to the next line */
@@ -391,7 +394,7 @@ int entab(int f, int n)
 			}
 
 			/* get the current character */
-			switch( lgetc( curwp->w_dotp, curwp->w_doto)) {
+			switch( curwbyte()) {
 			case '\t':	/* a tab...count em up */
 				ccol = nextab(ccol);
 				break;
@@ -967,7 +970,7 @@ int getfence(int f, int n)
 
 		/* if no eol */
 		if( curwp->w_doto != llength(curwp->w_dotp)) {
-			c = lgetc( curwp->w_dotp, curwp->w_doto) ;
+			c = curwbyte() ;
 			if( c == ch)
 				++count ;
 			else if( c == ofence)
diff --git a/window.h b/window.h
index e9351ec..8a7f781 100644
--- a/window.h
+++ b/window.h
@@ -13,13 +13,13 @@
  * the full blown redisplay is just too expensive to run for every input
  * character.
  */
-struct window {
+typedef struct window {
 	struct window *w_wndp;	/* Next window                  */
 	struct buffer *w_bufp;	/* Buffer displayed in window   */
-	struct line *w_linep;	/* Top line in the window       */
-	struct line *w_dotp;	/* Line containing "."          */
-	struct line *w_markp;	/* Line containing "mark"       */
-	int w_doto;		/* Byte offset for "."          */
+	line_p	w_linep ;		/* Top line in the window       */
+	line_p	w_dotp ;		/* Line containing "."          */
+	line_p	w_markp ;		/* Line containing "mark"       */
+	int w_doto ;			/* Byte offset for "."          */
 	int w_marko;		/* Byte offset for "mark"       */
 	int w_toprow ;		/* Origin 0 top row of window   */
 	int w_ntrows ;		/* # of rows of text in window  */
@@ -29,10 +29,13 @@ struct window {
 	char w_fcolor;		/* current forground color      */
 	char w_bcolor;		/* current background color     */
 #endif
-};
+} *window_p ;
 
-extern struct window *curwp ;	/* Current window               */
-extern struct window *wheadp ;	/* Head of list of windows      */
+extern window_p curwp ;		/* Current window               */
+extern window_p wheadp ;	/* Head of list of windows      */
+
+/* curwbyte return the byte after the dot in current window */
+#define curwbyte() lgetc( curwp->w_dotp, curwp->w_doto)
 
 #define WFFORCE 0x01		/* Window needs forced reframe  */
 #define WFMOVE  0x02		/* Movement from line to line   */
@@ -66,6 +69,6 @@ int newsize( int f, int n) ;
 int newwidth( int f, int n) ;
 int getwpos( void) ;
 void cknewwindow( void) ;
-struct window *wpopup( void) ;  /* Pop up window creation. */
+window_p wpopup( void) ;  /* Pop up window creation. */
 
 #endif