Review forwchar and backchar.

ebind.c

@@ -37,7 +37,7 @@
 struct key_tab keytab[NBINDS] = {
     {CONTROL | 'A', gotobol}
     ,
-    {CONTROL | 'B', backchar}
+    {CONTROL | 'B', (fn_t) backchar}
     ,
     {CONTROL | 'C', insspace}
     ,
@@ -45,7 +45,7 @@ struct key_tab keytab[NBINDS] = {
     ,
     {CONTROL | 'E', gotoeol}
     ,
-    {CONTROL | 'F', forwchar}
+    {CONTROL | 'F', (fn_t) forwchar}
     ,
     {CONTROL | 'G', ctrlg}
     ,
@@ -329,9 +329,9 @@ struct key_tab keytab[NBINDS] = {
     ,
     {SPEC | 73, backpage}
     ,
-    {SPEC | 75, backchar}
+    {SPEC | 75, (fn_t) backchar}
     ,
-    {SPEC | 77, forwchar}
+    {SPEC | 77, (fn_t) forwchar}
     ,
     {SPEC | 79, gotoeol}
     ,
@@ -406,13 +406,13 @@ struct key_tab keytab[NBINDS] = {
     ,
     {SPEC | 'B', forwline}
     ,
-    {SPEC | 'C', forwchar}
+    {SPEC | 'C', (fn_t) forwchar}
     ,
-    {SPEC | 'D', backchar}
+    {SPEC | 'D', (fn_t) backchar}
     ,
     {SPEC | 'c', metafn}
     ,
-    {SPEC | 'd', backchar}
+    {SPEC | 'd', (fn_t) backchar}
     ,
     {SPEC | 'e', forwline}
     ,

line.c

@@ -91,32 +91,11 @@ char *getkill( void) {
  * location. Error if you try and move out of the buffer. Set the flag if the
  * line pointer for dot changes.
  */
-int backchar( int f, int n) {
-	if( n < 0)
-		return forwchar( f, -n) ;
+static unsigned utf8_revdelta( unsigned char *p, unsigned pos) {
+	unsigned delta = 0 ;
 
-	while( n--) {
-		if( curwp->w_doto == 0) {
-			struct line *lp ;
-
-			lp = lback( curwp->w_dotp) ;
-			if( lp == curbp->b_linep)
-				return FALSE ;
-
-			curwp->w_dotp = lp ;
-			curwp->w_doto = llength( lp) ;
-			curwp->w_flag |= WFMOVE ;
-		} else {
-			unsigned pos ;
-			
-			pos = curwp->w_doto -= 1 ;
-			if( pos > 0) {
-				unsigned char *p ;
-
-				p = (unsigned char *) &( (curwp->w_dotp)->l_text[ pos]) ;
 	if( (*p & 0xC0) == 0x80) {
 		unsigned char c ;
-					int delta = 0 ;
 
 		c = *--p ;
 		if( (c & 0xE0) == 0xC0)	/* valid 2 bytes unicode seq */
@@ -129,10 +108,32 @@ int backchar( int f, int n) {
 				if( (p[ -1] & 0xF8) == 0xF0)	/* valid 4 bytes unicode seq */
 					delta = 3 ;
 		}
+	}
 
-					curwp->w_doto -= delta ;
-				}
+	return delta ;
 }
+
+boolean backchar( int f, int n) {
+	if( n < 0)
+		return forwchar( f, -n) ;
+
+	while( n--) {
+		if( curwp->w_doto == 0) {	/* at beginning of line */
+			line_p lp ;
+
+			lp = lback( curwp->w_dotp) ;
+			if( lp == curbp->b_linep)	/* at beginning of buffer */
+				return FALSE ;
+
+			curwp->w_dotp = lp ;
+			curwp->w_doto = llength( lp) ;
+			curwp->w_flag |= WFMOVE ;
+		} else {
+			unsigned pos ;
+			
+			pos = curwp->w_doto -= 1 ;
+			if( pos > 0)
+				curwp->w_doto -= utf8_revdelta( (unsigned char *) &( (curwp->w_dotp)->l_text[ pos]), pos) ;
 		}
 	}
 
@@ -145,15 +146,16 @@ int backchar( int f, int n) {
  * location, and move ".". Error if you try and move off the end of the
  * buffer. Set the flag if the line pointer for dot changes.
  */
-int forwchar(int f, int n)
-{
+boolean forwchar( int f, int n) {
 	if( n < 0)
 		return backchar( f, -n) ;
+
 	while( n--) {
 		int len = llength( curwp->w_dotp) ;
-		if (curwp->w_doto == len) {
-			if (curwp->w_dotp == curbp->b_linep)
+		if( curwp->w_doto == len) {	/* at end of line */
+			if( curwp->w_dotp == curbp->b_linep)	/* at end of buffer */
 				return FALSE ;
+
 			curwp->w_dotp = lforw( curwp->w_dotp) ;
 			curwp->w_doto = 0 ;
 			curwp->w_flag |= WFMOVE ;
@@ -165,6 +167,7 @@ int forwchar(int f, int n)
 			curwp->w_doto += bytes ;
 		}
 	}
+
 	return TRUE ;
 }
 

line.h

@@ -30,8 +30,8 @@ extern int tabwidth ;	/* Map to $tab, default to 8, can be set to [1, .. */
 
 char *getkill( void) ;
 
-int backchar( int f, int n) ;
-int forwchar( int f, int n) ;
+boolean backchar( int f, int n) ;
+boolean forwchar( int f, int n) ;
 
 void lfree( line_p lp) ;
 void lchange( int flag) ;

names.c

@@ -34,7 +34,7 @@ struct name_bind names[] = {
 #if	APROP
 	{"apropos", apro},
 #endif
-	{"backward-character", backchar},
+	{"backward-character", (fn_t) backchar},
 	{"begin-macro", ctlxlp},
 	{"beginning-of-file", gotobob},
 	{"beginning-of-line", gotobol},
@@ -132,7 +132,7 @@ struct name_bind names[] = {
 #endif
 	{"filter-buffer", filter_buffer},
 	{"find-file", filefind},
-	{"forward-character", forwchar},
+	{"forward-character", (fn_t) forwchar},
 	{"goto-line", gotoline},
 #if	CFENCE
 	{"goto-matching-fence", getfence},

random.c

@@ -705,7 +705,7 @@ int backdel( int f, int n) {
 		thisflag |= CFKILL;
 	}
 
-	return (backchar( f, n) == TRUE) && ldelchar( n, f != FALSE) ;
+	return backchar( f, n) && ldelchar( n, f != FALSE) ;
 }
 
 /*