factored code and fixed behaviour of tnewline().

diff --git a/st.c b/st.c
index 0c876f5..5633e40 100644 (file)
--- a/st.c
+++ b/st.c
@@ -161,8 +161,8 @@ static void tputc(char);
 static void tputs(char*, int);
 static void treset(void);
 static void tresize(int, int);
-static void tscrollup(int);
-static void tscrolldown(int);
+static void tscrollup(int, int);
+static void tscrolldown(int, int);
 static void tsetattr(int*, int);
 static void tsetchar(char);
 static void tsetscroll(int, int);
@@ -459,15 +459,15 @@ tswapscreen(void) {
 }
 
 void
-tscrolldown (int n) {
+tscrolldown(int orig, int n) {
        int i;
        Line temp;
        
-       LIMIT(n, 0, term.bot-term.top+1);
+       LIMIT(n, 0, term.bot-orig+1);
 
        tclearregion(0, term.bot-n+1, term.col-1, term.bot);
        
-       for(i = term.bot; i >= term.top+n; i--) {
+       for(i = term.bot; i >= orig+n; i--) {
                temp = term.line[i];
                term.line[i] = term.line[i-n];
                term.line[i-n] = temp;
@@ -475,14 +475,14 @@ tscrolldown (int n) {
 }
 
 void
-tscrollup (int n) {
+tscrollup(int orig, int n) {
        int i;
        Line temp;
-       LIMIT(n, 0, term.bot-term.top+1);
+       LIMIT(n, 0, term.bot-orig+1);
        
-       tclearregion(0, term.top, term.col-1, term.top+n-1);
+       tclearregion(0, orig, term.col-1, orig+n-1);
        
-       for(i = term.top; i <= term.bot-n; i++) { 
+       for(i = orig; i <= term.bot-n; i++) { 
                 temp = term.line[i];
                 term.line[i] = term.line[i+n]; 
                 term.line[i+n] = temp;
@@ -491,9 +491,11 @@ tscrollup (int n) {
 
 void
 tnewline(void) {
-       int y = term.c.y + 1;
-       if(y > term.bot)
-               tscrollup(1), y = term.bot;
+       int y = term.c.y;
+       if(term.c.y == term.bot)
+               tscrollup(term.top, 1);
+       else
+               y++;
        tmoveto(0, y);
 }
 
@@ -585,40 +587,18 @@ tinsertblank(int n) {
 
 void
 tinsertblankline(int n) {
-       int i;
-       Line blank;
-       int bot = term.bot;
-
        if(term.c.y < term.top || term.c.y > term.bot)
                return;
 
-       LIMIT(n, 0, bot-term.c.y+1);
-       tclearregion(0, bot-n+1, term.col-1, bot);
-       for(i = bot; i >= term.c.y+n; i--) {
-               /* swap deleted line <-> blanked line */
-               blank = term.line[i];
-               term.line[i] = term.line[i-n];
-               term.line[i-n] = blank;
-       }
+       tscrolldown(term.c.y, n);
 }
 
 void
 tdeleteline(int n) {
-       int i;
-       Line blank;
-       int bot = term.bot;
-
        if(term.c.y < term.top || term.c.y > term.bot)
                return;
 
-       LIMIT(n, 0, bot-term.c.y+1);
-       tclearregion(0, term.c.y, term.col-1, term.c.y+n-1);
-       for(i = term.c.y; i <= bot-n; i++) {
-               /* swap deleted line <-> blanked line */
-               blank = term.line[i];
-               term.line[i] = term.line[i+n];
-               term.line[i+n] = blank;
-       }
+       tscrollup(term.c.y, n);
 }
 
 void
@@ -790,11 +770,11 @@ csihandle(void) {
                break;
        case 'S': /* SU -- Scroll <n> line up */
                DEFAULT(escseq.arg[0], 1);
-               tscrollup(escseq.arg[0]);
+               tscrollup(term.top, escseq.arg[0]);
                break;
        case 'T': /* SD -- Scroll <n> line down */
                DEFAULT(escseq.arg[0], 1);
-               tscrolldown(escseq.arg[0]);
+               tscrolldown(term.top, escseq.arg[0]);
                break;
        case 'L': /* IL -- Insert <n> blank lines */
                DEFAULT(escseq.arg[0], 1);
@@ -984,7 +964,7 @@ tputc(char c) {
                                break;
                        case 'D': /* IND -- Linefeed */
                                if(term.c.y == term.bot)
-                                       tscrollup(1);
+                                       tscrollup(term.top, 1);
                                else
                                        tmoveto(term.c.x, term.c.y+1);
                                term.esc = 0;
@@ -995,7 +975,7 @@ tputc(char c) {
                                break;
                        case 'M': /* RI -- Reverse index */
                                if(term.c.y == term.top)
-                                       tscrolldown(1);
+                                       tscrolldown(term.top, 1);
                                else
                                        tmoveto(term.c.x, term.c.y-1);
                                term.esc = 0;