From 38d2f7ba589e8ee0ee5ded7915952ed094e3a51a Mon Sep 17 00:00:00 2001
From: ZachIR <zachir@librem.one>
Date: Tue, 8 Jul 2025 20:39:57 -0500
Subject: Start from scratch on version 0.9.2

---
 st.c | 1221 ++++++++++++++++--------------------------------------------------
 1 file changed, 293 insertions(+), 928 deletions(-)

(limited to 'st.c')

diff --git a/st.c b/st.c
index 1ec550a..b9f66e7 100644
--- a/st.c
+++ b/st.c
@@ -33,11 +33,8 @@
 #define UTF_SIZ       4
 #define ESC_BUF_SIZ   (128*UTF_SIZ)
 #define ESC_ARG_SIZ   16
-#define CAR_PER_ARG   4
 #define STR_BUF_SIZ   ESC_BUF_SIZ
 #define STR_ARG_SIZ   ESC_ARG_SIZ
-#define HISTSIZE      2000
-#define RESIZEBUFFER  2000
 
 /* macros */
 #define IS_SET(flag)		((term.mode & (flag)) != 0)
@@ -45,24 +42,6 @@
 #define ISCONTROLC1(c)		(BETWEEN(c, 0x80, 0x9f))
 #define ISCONTROL(c)		(ISCONTROLC0(c) || ISCONTROLC1(c))
 #define ISDELIM(u)		(u && wcschr(worddelimiters, u))
-#define STRESCARGREST(n)	((n) == 0 ? strescseq.buf : strescseq.argp[(n)-1] + 1)
-#define STRESCARGJUST(n)	(*(strescseq.argp[n]) = '\0', STRESCARGREST(n))
-
-#define TLINE(y) ( \
-	(y) < term.scr ? term.hist[(term.histi + (y) - term.scr + 1 + HISTSIZE) % HISTSIZE] \
-	               : term.line[(y) - term.scr] \
-)
-
-#define TLINEABS(y) ( \
-	(y) < 0 ? term.hist[(term.histi + (y) + 1 + HISTSIZE) % HISTSIZE] : term.line[(y)] \
-)
-
-#define UPDATEWRAPNEXT(alt, col) do { \
-	if ((term.c.state & CURSOR_WRAPNEXT) && term.c.x + term.wrapcwidth[alt] < col) { \
-		term.c.x += term.wrapcwidth[alt]; \
-		term.c.state &= ~CURSOR_WRAPNEXT; \
-	} \
-} while (0);
 
 enum term_mode {
 	MODE_WRAP        = 1 << 0,
@@ -74,12 +53,6 @@ enum term_mode {
 	MODE_UTF8        = 1 << 6,
 };
 
-enum scroll_mode {
-	SCROLL_RESIZE = -1,
-	SCROLL_NOSAVEHIST = 0,
-	SCROLL_SAVEHIST = 1
-};
-
 enum cursor_movement {
 	CURSOR_SAVE,
 	CURSOR_LOAD
@@ -141,11 +114,7 @@ typedef struct {
 	int row;      /* nb row */
 	int col;      /* nb col */
 	Line *line;   /* screen */
-	Line hist[HISTSIZE]; /* history buffer */
-	int histi;           /* history index */
-	int histf;           /* nb history available */
-	int scr;             /* scroll back */
-	int wrapcwidth[2];   /* used in updating WRAPNEXT when resizing */
+	Line *alt;    /* alternate screen */
 	int *dirty;   /* dirtyness of lines */
 	TCursor c;    /* cursor */
 	int ocx;      /* old cursor col */
@@ -170,7 +139,6 @@ typedef struct {
 	int arg[ESC_ARG_SIZ];
 	int narg;              /* nb of args */
 	char mode[2];
-	int carg[ESC_ARG_SIZ][CAR_PER_ARG]; /* colon args */
 } CSIEscape;
 
 /* STR Escape sequence structs */
@@ -180,24 +148,17 @@ typedef struct {
 	char *buf;             /* allocated raw string */
 	size_t siz;            /* allocation size */
 	size_t len;            /* raw string length */
-	char *argp[STR_ARG_SIZ]; /* pointers to the end of nth argument */
+	char *args[STR_ARG_SIZ];
 	int narg;              /* nb of args */
 } STREscape;
 
-typedef struct {
-	int state;
-	size_t length;
-} URLdfa;
-
 static void execsh(char *, char **);
 static void stty(char **);
 static void sigchld(int);
 static void ttywriteraw(const char *, size_t);
 
-static void histclean(void);
 static void csidump(void);
 static void csihandle(void);
-static void readcolonargs(char **, int, int[][CAR_PER_ARG]);
 static void csiparse(void);
 static void csireset(void);
 static void osc_color_response(int, int, int);
@@ -211,54 +172,40 @@ static void tprinter(char *, size_t);
 static void tdumpsel(void);
 static void tdumpline(int);
 static void tdump(void);
-static void tclearregion(int, int, int, int, int);
+static void tclearregion(int, int, int, int);
 static void tcursor(int);
-static void tclearglyph(Glyph *, int);
-static void tresetcursor(void);
 static void tdeletechar(int);
 static void tdeleteline(int);
 static void tinsertblank(int);
 static void tinsertblankline(int);
-static int tlinelen(Line len);
-static int tiswrapped(Line line);
-static char *tgetglyphs(char *, const Glyph *, const Glyph *);
-static size_t tgetline(char *, const Glyph *);
+static int tlinelen(int);
 static void tmoveto(int, int);
 static void tmoveato(int, int);
 static void tnewline(int);
 static void tputtab(int);
 static void tputc(Rune);
 static void treset(void);
-static void tscrollup(int, int, int, int);
+static void tscrollup(int, int);
 static void tscrolldown(int, int);
-static void treflow(int, int);
-static void rscrolldown(int);
-static void tresizedef(int, int);
-static void tresizealt(int, int);
 static void tsetattr(const int *, int);
 static void tsetchar(Rune, const Glyph *, int, int);
 static void tsetdirt(int, int);
 static void tsetscroll(int, int);
 static void tswapscreen(void);
-static void tloaddefscreen(int, int);
-static void tloadaltscreen(int, int);
 static void tsetmode(int, int, const int *, int);
 static int twrite(const char *, int, int);
+static void tfulldirt(void);
 static void tcontrolcode(uchar );
 static void tdectest(char );
 static void tdefutf8(char);
 static int32_t tdefcolor(const int *, int *, int);
 static void tdeftran(char);
 static void tstrsequence(uchar);
-static int daddch(URLdfa *, char);
 
 static void drawregion(int, int, int, int);
 
 static void selnormalize(void);
-static void selscroll(int, int, int);
-static void selmove(int);
-static void selremove(void);
-static int regionselected(int, int, int, int);
+static void selscroll(int, int);
 static void selsnap(int *, int *, int);
 
 static size_t utf8decode(const char *, Rune *, size_t);
@@ -285,33 +232,6 @@ static const uchar utfmask[UTF_SIZ + 1] = {0xC0, 0x80, 0xE0, 0xF0, 0xF8};
 static const Rune utfmin[UTF_SIZ + 1] = {       0,    0,  0x80,  0x800,  0x10000};
 static const Rune utfmax[UTF_SIZ + 1] = {0x10FFFF, 0x7F, 0x7FF, 0xFFFF, 0x10FFFF};
 
-#include <time.h>
-static int su = 0;
-struct timespec sutv;
-
-static void
-tsync_begin()
-{
-	clock_gettime(CLOCK_MONOTONIC, &sutv);
-	su = 1;
-}
-
-static void
-tsync_end()
-{
-	su = 0;
-}
-
-int
-tinsync(uint timeout)
-{
-	struct timespec now;
-	if (su && !clock_gettime(CLOCK_MONOTONIC, &now)
-	       && TIMEDIFF(now, sutv) >= timeout)
-		su = 0;
-	return su;
-}
-
 ssize_t
 xwrite(int fd, const char *s, size_t len)
 {
@@ -485,46 +405,17 @@ selinit(void)
 }
 
 int
-tlinelen(Line line)
+tlinelen(int y)
 {
-	int i = term.col - 1;
+	int i = term.col;
 
-	for (; i >= 0 && !(line[i].mode & (ATTR_SET | ATTR_WRAP)); i--);
-	return i + 1;
-}
+	if (term.line[y][i - 1].mode & ATTR_WRAP)
+		return i;
 
-int
-tiswrapped(Line line)
-{
-	int len = tlinelen(line);
+	while (i > 0 && term.line[y][i - 1].u == ' ')
+		--i;
 
-	return len > 0 && (line[len - 1].mode & ATTR_WRAP);
-}
-
-char *
-tgetglyphs(char *buf, const Glyph *gp, const Glyph *lgp)
-{
-	while (gp <= lgp)
-		if (gp->mode & ATTR_WDUMMY) {
-			gp++;
-		} else {
-			buf += utf8encode((gp++)->u, buf);
-		}
-	return buf;
-}
-
-size_t
-tgetline(char *buf, const Glyph *fgp)
-{
-	char *ptr;
-	const Glyph *lgp = &fgp[term.col - 1];
-
-	while (lgp > fgp && !(lgp->mode & (ATTR_SET | ATTR_WRAP)))
-		lgp--;
-	ptr = tgetglyphs(buf, fgp, lgp);
-	if (!(lgp->mode & ATTR_WRAP))
-		*(ptr++) = '\n';
-	return ptr - buf;
+	return i;
 }
 
 void
@@ -564,11 +455,10 @@ selextend(int col, int row, int type, int done)
 
 	sel.oe.x = col;
 	sel.oe.y = row;
-	sel.type = type;
 	selnormalize();
+	sel.type = type;
 
-	if (oldey != sel.oe.y || oldex != sel.oe.x ||
-	    oldtype != sel.type || sel.mode == SEL_EMPTY)
+	if (oldey != sel.oe.y || oldex != sel.oe.x || oldtype != sel.type || sel.mode == SEL_EMPTY)
 		tsetdirt(MIN(sel.nb.y, oldsby), MAX(sel.ne.y, oldsey));
 
 	sel.mode = done ? SEL_IDLE : SEL_READY;
@@ -595,50 +485,43 @@ selnormalize(void)
 	/* expand selection over line breaks */
 	if (sel.type == SEL_RECTANGULAR)
 		return;
-
-  i = tlinelen(TLINE(sel.nb.y));
-	if (sel.nb.x > i)
+	i = tlinelen(sel.nb.y);
+	if (i < sel.nb.x)
 		sel.nb.x = i;
-  if (sel.ne.x >= tlinelen(TLINE(sel.ne.y)))
-    sel.ne.x = term.col - 1;
+	if (tlinelen(sel.ne.y) <= sel.ne.x)
+		sel.ne.x = term.col - 1;
 }
 
 int
-regionselected(int x1, int y1, int x2, int y2)
+selected(int x, int y)
 {
-	if (sel.ob.x == -1 || sel.mode == SEL_EMPTY ||
-	    sel.alt != IS_SET(MODE_ALTSCREEN) || sel.nb.y > y2 || sel.ne.y < y1)
+	if (sel.mode == SEL_EMPTY || sel.ob.x == -1 ||
+			sel.alt != IS_SET(MODE_ALTSCREEN))
 		return 0;
 
-	return (sel.type == SEL_RECTANGULAR) ? sel.nb.x <= x2 && sel.ne.x >= x1
-		: (sel.nb.y != y2 || sel.nb.x <= x2) &&
-		  (sel.ne.y != y1 || sel.ne.x >= x1);
-}
+	if (sel.type == SEL_RECTANGULAR)
+		return BETWEEN(y, sel.nb.y, sel.ne.y)
+		    && BETWEEN(x, sel.nb.x, sel.ne.x);
 
-int
-selected(int x, int y)
-{
-	return regionselected(x, y, x, y);
+	return BETWEEN(y, sel.nb.y, sel.ne.y)
+	    && (y != sel.nb.y || x >= sel.nb.x)
+	    && (y != sel.ne.y || x <= sel.ne.x);
 }
 
 void
 selsnap(int *x, int *y, int direction)
 {
 	int newx, newy, xt, yt;
-	int rtop = 0, rbot = term.row - 1;
 	int delim, prevdelim;
 	const Glyph *gp, *prevgp;
 
-	if (!IS_SET(MODE_ALTSCREEN))
-		rtop += -term.histf + term.scr, rbot += term.scr;
-
 	switch (sel.snap) {
 	case SNAP_WORD:
 		/*
 		 * Snap around if the word wraps around at the end or
 		 * beginning of a line.
 		 */
-		prevgp = &TLINE(*y)[*x];
+		prevgp = &term.line[*y][*x];
 		prevdelim = ISDELIM(prevgp->u);
 		for (;;) {
 			newx = *x + direction;
@@ -646,24 +529,24 @@ selsnap(int *x, int *y, int direction)
 			if (!BETWEEN(newx, 0, term.col - 1)) {
 				newy += direction;
 				newx = (newx + term.col) % term.col;
-				if (!BETWEEN(newy, rtop, rbot))
+				if (!BETWEEN(newy, 0, term.row - 1))
 					break;
 
 				if (direction > 0)
 					yt = *y, xt = *x;
 				else
 					yt = newy, xt = newx;
-				if (!(TLINE(yt)[xt].mode & ATTR_WRAP))
+				if (!(term.line[yt][xt].mode & ATTR_WRAP))
 					break;
 			}
 
-			if (newx >= tlinelen(TLINE(newy)))
+			if (newx >= tlinelen(newy))
 				break;
 
-			gp = &TLINE(newy)[newx];
+			gp = &term.line[newy][newx];
 			delim = ISDELIM(gp->u);
-			if (!(gp->mode & ATTR_WDUMMY) && (delim != prevdelim ||
-			    (delim && !(gp->u == ' ' && prevgp->u == ' '))))
+			if (!(gp->mode & ATTR_WDUMMY) && (delim != prevdelim
+					|| (delim && gp->u != prevgp->u)))
 				break;
 
 			*x = newx;
@@ -680,14 +563,18 @@ selsnap(int *x, int *y, int direction)
 		 */
 		*x = (direction < 0) ? 0 : term.col - 1;
 		if (direction < 0) {
-			for (; *y > rtop; *y -= 1) {
-				if (!tiswrapped(TLINE(*y-1)))
+			for (; *y > 0; *y += direction) {
+				if (!(term.line[*y-1][term.col-1].mode
+						& ATTR_WRAP)) {
 					break;
+				}
 			}
 		} else if (direction > 0) {
-			for (; *y < rbot; *y += 1) {
-				if (!tiswrapped(TLINE(*y)))
+			for (; *y < term.row-1; *y += direction) {
+				if (!(term.line[*y][term.col-1].mode
+						& ATTR_WRAP)) {
 					break;
+				}
 			}
 		}
 		break;
@@ -698,34 +585,40 @@ char *
 getsel(void)
 {
 	char *str, *ptr;
-	int y, lastx, linelen;
-	const Glyph *gp, *lgp;
+	int y, bufsize, lastx, linelen;
+	const Glyph *gp, *last;
 
-	if (sel.ob.x == -1 || sel.alt != IS_SET(MODE_ALTSCREEN))
+	if (sel.ob.x == -1)
 		return NULL;
 
-	str = xmalloc((term.col + 1) * (sel.ne.y - sel.nb.y + 1) * UTF_SIZ);
-	ptr = str;
+	bufsize = (term.col+1) * (sel.ne.y-sel.nb.y+1) * UTF_SIZ;
+	ptr = str = xmalloc(bufsize);
 
 	/* append every set & selected glyph to the selection */
 	for (y = sel.nb.y; y <= sel.ne.y; y++) {
-		Line line = TLINE(y);
-
-		if ((linelen = tlinelen(line)) == 0) {
+		if ((linelen = tlinelen(y)) == 0) {
 			*ptr++ = '\n';
 			continue;
 		}
 
 		if (sel.type == SEL_RECTANGULAR) {
-			gp = &line[sel.nb.x];
+			gp = &term.line[y][sel.nb.x];
 			lastx = sel.ne.x;
 		} else {
-			gp = &line[sel.nb.y == y ? sel.nb.x : 0];
+			gp = &term.line[y][sel.nb.y == y ? sel.nb.x : 0];
 			lastx = (sel.ne.y == y) ? sel.ne.x : term.col-1;
 		}
-		lgp = &line[MIN(lastx, linelen-1)];
+		last = &term.line[y][MIN(lastx, linelen-1)];
+		while (last >= gp && last->u == ' ')
+			--last;
+
+		for ( ; gp <= last; ++gp) {
+			if (gp->mode & ATTR_WDUMMY)
+				continue;
+
+			ptr += utf8encode(gp->u, ptr);
+		}
 
-		ptr = tgetglyphs(ptr, gp, lgp);
 		/*
 		 * Copy and pasting of line endings is inconsistent
 		 * in the inconsistent terminal and GUI world.
@@ -736,10 +629,10 @@ getsel(void)
 		 * FIXME: Fix the computer world.
 		 */
 		if ((y < sel.ne.y || lastx >= linelen) &&
-		    (!(lgp->mode & ATTR_WRAP) || sel.type == SEL_RECTANGULAR))
+		    (!(last->mode & ATTR_WRAP) || sel.type == SEL_RECTANGULAR))
 			*ptr++ = '\n';
 	}
-	*ptr = '\0';
+	*ptr = 0;
 	return str;
 }
 
@@ -748,15 +641,9 @@ selclear(void)
 {
 	if (sel.ob.x == -1)
 		return;
-	selremove();
-	tsetdirt(sel.nb.y, sel.ne.y);
-}
-
-void
-selremove(void)
-{
 	sel.mode = SEL_IDLE;
 	sel.ob.x = -1;
+	tsetdirt(sel.nb.y, sel.ne.y);
 }
 
 void
@@ -927,9 +814,6 @@ ttynew(const char *line, char *cmd, const char *out, char **args)
 	return cmdfd;
 }
 
-static int twrite_aborted = 0;
-int ttyread_pending() { return twrite_aborted; }
-
 size_t
 ttyread(void)
 {
@@ -938,7 +822,7 @@ ttyread(void)
 	int ret, written;
 
 	/* append read bytes to unprocessed bytes */
-	ret = twrite_aborted ? 1 : read(cmdfd, buf+buflen, LEN(buf)-buflen);
+	ret = read(cmdfd, buf+buflen, LEN(buf)-buflen);
 
 	switch (ret) {
 	case 0:
@@ -946,7 +830,7 @@ ttyread(void)
 	case -1:
 		die("couldn't read from shell: %s\n", strerror(errno));
 	default:
-		buflen += twrite_aborted ? 0 : ret;
+		buflen += ret;
 		written = twrite(buf, buflen, 0);
 		buflen -= written;
 		/* keep any incomplete UTF-8 byte sequence for the next call */
@@ -961,7 +845,6 @@ ttywrite(const char *s, size_t n, int may_echo)
 {
 	const char *next;
 
-	kscrolldown(&((Arg){ .i = term.scr }));
 	if (may_echo && IS_SET(MODE_ECHO))
 		twrite(s, n, 1);
 
@@ -985,14 +868,6 @@ ttywrite(const char *s, size_t n, int may_echo)
 	}
 }
 
-void
-histclean()
-{
-  for (int i = 0; i < HISTSIZE; i++)
-    term.hist[i] = xmalloc(term.col * sizeof(Glyph));
-  term.histf = 0;
-}
-
 void
 ttywriteraw(const char *s, size_t n)
 {
@@ -1097,11 +972,6 @@ tsetdirt(int top, int bot)
 		term.dirty[i] = 1;
 }
 
-int tisaltscr(void)
-{
-	return IS_SET(MODE_ALTSCREEN);
-}
-
 void
 tsetdirtattr(int attr)
 {
@@ -1110,7 +980,7 @@ tsetdirtattr(int attr)
 	for (i = 0; i < term.row-1; i++) {
 		for (j = 0; j < term.col-1; j++) {
 			if (term.line[i][j].mode & attr) {
-				term.dirty[i] = 1;
+				tsetdirt(i, i);
 				break;
 			}
 		}
@@ -1120,9 +990,7 @@ tsetdirtattr(int attr)
 void
 tfulldirt(void)
 {
-        tsync_end();
-        for (int i = 0; i < term.row; i++)
-		term.dirty[i] = 1;
+	tsetdirt(0, term.row-1);
 }
 
 void
@@ -1139,258 +1007,110 @@ tcursor(int mode)
 	}
 }
 
-void
-tresetcursor(void)
-{
-	term.c = (TCursor){ { .mode = ATTR_NULL, .fg = defaultfg, .bg = defaultbg },
-	                    .x = 0, .y = 0, .state = CURSOR_DEFAULT };
-}
-
 void
 treset(void)
 {
 	uint i;
-  int x, y;
 
-	tresetcursor();
+	term.c = (TCursor){{
+		.mode = ATTR_NULL,
+		.fg = defaultfg,
+		.bg = defaultbg
+	}, .x = 0, .y = 0, .state = CURSOR_DEFAULT};
 
 	memset(term.tabs, 0, term.col * sizeof(*term.tabs));
 	for (i = tabspaces; i < term.col; i += tabspaces)
 		term.tabs[i] = 1;
 	term.top = 0;
-	term.histf = 0;
-	term.scr = 0;
 	term.bot = term.row - 1;
 	term.mode = MODE_WRAP|MODE_UTF8;
 	memset(term.trantbl, CS_USA, sizeof(term.trantbl));
 	term.charset = 0;
 
-  selremove();
 	for (i = 0; i < 2; i++) {
-  	tcursor(CURSOR_SAVE); /* reset saved cursor */
-		for (y = 0; y < term.row; y++)
-			for (x = 0; x < term.col; x++)
-				tclearglyph(&term.line[y][x], 0);
+		tmoveto(0, 0);
+		tcursor(CURSOR_SAVE);
+		tclearregion(0, 0, term.col-1, term.row-1);
 		tswapscreen();
 	}
-  tfulldirt();
 }
 
 void
 tnew(int col, int row)
 {
-	int i, j;
-
-	for (i = 0; i < 2; i++) {
-		term.line = xmalloc(row * sizeof(Line));
-		for (j = 0; j < row; j++)
-			term.line[j] = xmalloc(col * sizeof(Glyph));
-		term.col = col, term.row = row;
-		tswapscreen();
-	}
-	term.dirty = xmalloc(row * sizeof(*term.dirty));
-	term.tabs = xmalloc(col * sizeof(*term.tabs));
-	for (i = 0; i < HISTSIZE; i++)
-		term.hist[i] = xmalloc(col * sizeof(Glyph));
-  treset();
+	term = (Term){ .c = { .attr = { .fg = defaultfg, .bg = defaultbg } } };
+	tresize(col, row);
+	treset();
 }
 
-/* handle it with care */
 void
 tswapscreen(void)
 {
-	static Line *altline;
-	static int altcol, altrow;
-	Line *tmpline = term.line;
-	int tmpcol = term.col, tmprow = term.row;
+	Line *tmp = term.line;
 
-	term.line = altline;
-	term.col = altcol, term.row = altrow;
-	altline = tmpline;
-	altcol = tmpcol, altrow = tmprow;
+	term.line = term.alt;
+	term.alt = tmp;
 	term.mode ^= MODE_ALTSCREEN;
-}
-
-void
-tloaddefscreen(int clear, int loadcursor)
-{
-	int col, row, alt = IS_SET(MODE_ALTSCREEN);
-
-	if (alt) {
-		if (clear)
-			tclearregion(0, 0, term.col-1, term.row-1, 1);
-		col = term.col, row = term.row;
-		tswapscreen();
-	}
-	if (loadcursor)
-		tcursor(CURSOR_LOAD);
-	if (alt)
-		tresizedef(col, row);
-}
-
-void
-tloadaltscreen(int clear, int savecursor)
-{
-	int col, row, def = !IS_SET(MODE_ALTSCREEN);
-
-	if (savecursor)
-		tcursor(CURSOR_SAVE);
-	if (def) {
-		col = term.col, row = term.row;
-		tswapscreen();
-		term.scr = 0;
-		tresizealt(col, row);
-	}
-	if (clear)
-		tclearregion(0, 0, term.col-1, term.row-1, 1);
-}
-
-int
-tisaltscreen(void)
-{
-	return IS_SET(MODE_ALTSCREEN);
-}
-
-void
-kscrolldown(const Arg* a)
-{
-	int n = a->i;
-
-	if (!term.scr || IS_SET(MODE_ALTSCREEN))
-		return;
-
-	if (n < 0)
-		n = MAX(term.row / -n, 1);
-
-	if (n <= term.scr) {
-		term.scr -= n;
-	} else {
-		n = term.scr;
-		term.scr = 0;
-	}
-
-	if (sel.ob.x != -1 && !sel.alt)
-		selmove(-n); /* negate change in term.scr */
 	tfulldirt();
 }
 
 void
-kscrollup(const Arg* a)
+tscrolldown(int orig, int n)
 {
-	int n = a->i;
-
-	if (!term.histf || IS_SET(MODE_ALTSCREEN))
-		return;
-
-	if (n < 0)
-		n = MAX(term.row / -n, 1);
-
-	if (term.scr + n <= term.histf) {
-		term.scr += n;
-	} else {
-		n = term.histf - term.scr;
-		term.scr = term.histf;
-	}
-
-	if (sel.ob.x != -1 && !sel.alt)
-		selmove(n); /* negate change in term.scr */
-	tfulldirt();
-}
-
-void
-tscrolldown(int top, int n)
-{
-	int i, bot = term.bot;
+	int i;
 	Line temp;
 
-	if (n <= 0)
-		return;
-	n = MIN(n, bot-top+1);
+	LIMIT(n, 0, term.bot-orig+1);
 
-	tsetdirt(top, bot-n);
-	tclearregion(0, bot-n+1, term.col-1, bot, 1);
+	tsetdirt(orig, term.bot-n);
+	tclearregion(0, term.bot-n+1, term.col-1, term.bot);
 
-	for (i = bot; i >= 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;
 	}
 
-	if (sel.ob.x != -1 && sel.alt == IS_SET(MODE_ALTSCREEN))
-		selscroll(top, bot, n);
+	selscroll(orig, n);
 }
 
 void
-tscrollup(int top, int bot, int n, int mode)
+tscrollup(int orig, int n)
 {
-	int i, j, s;
-	int alt = IS_SET(MODE_ALTSCREEN);
-	int savehist = !alt && top == 0 && mode != SCROLL_NOSAVEHIST;
+	int i;
 	Line temp;
 
-	if (n <= 0)
-		return;
-	n = MIN(n, bot-top+1);
-
-	if (savehist) {
-		for (i = 0; i < n; i++) {
-			term.histi = (term.histi + 1) % HISTSIZE;
-			temp = term.hist[term.histi];
-			for (j = 0; j < term.col; j++)
-				tclearglyph(&temp[j], 1);
-			term.hist[term.histi] = term.line[i];
-			term.line[i] = temp;
-		}
-		term.histf = MIN(term.histf + n, HISTSIZE);
-		s = n;
-		if (term.scr) {
-			j = term.scr;
-			term.scr = MIN(j + n, HISTSIZE);
-			s = j + n - term.scr;
-		}
-		if (mode != SCROLL_RESIZE)
-			tfulldirt();
-	} else {
-		tclearregion(0, top, term.col-1, top+n-1, 1);
-		tsetdirt(top+n, bot);
-	}
+	LIMIT(n, 0, term.bot-orig+1);
+
+	tclearregion(0, orig, term.col-1, orig+n-1);
+	tsetdirt(orig+n, term.bot);
 
-	for (i = top; i <= 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;
 	}
 
-	if (sel.ob.x != -1 && sel.alt == alt) {
-		if (!savehist) {
-			selscroll(top, bot, -n);
-		} else if (s > 0) {
-			selmove(-s);
-			if (-term.scr + sel.nb.y < -term.histf)
-				selremove();
-		}
-	}
+	selscroll(orig, -n);
 }
 
 void
-selmove(int n)
+selscroll(int orig, int n)
 {
-	sel.ob.y += n, sel.nb.y += n;
-	sel.oe.y += n, sel.ne.y += n;
-}
-
-void
-selscroll(int top, int bot, int n)
-{
-	/* turn absolute coordinates into relative */
-	top += term.scr, bot += term.scr;
+	if (sel.ob.x == -1 || sel.alt != IS_SET(MODE_ALTSCREEN))
+		return;
 
-	if (BETWEEN(sel.nb.y, top, bot) != BETWEEN(sel.ne.y, top, bot)) {
+	if (BETWEEN(sel.nb.y, orig, term.bot) != BETWEEN(sel.ne.y, orig, term.bot)) {
 		selclear();
-	} else if (BETWEEN(sel.nb.y, top, bot)) {
-		selmove(n);
-		if (sel.nb.y < top || sel.ne.y > bot)
+	} else if (BETWEEN(sel.nb.y, orig, term.bot)) {
+		sel.ob.y += n;
+		sel.oe.y += n;
+		if (sel.ob.y < term.top || sel.ob.y > term.bot ||
+		    sel.oe.y < term.top || sel.oe.y > term.bot) {
 			selclear();
+		} else {
+			selnormalize();
+		}
 	}
 }
 
@@ -1400,35 +1120,13 @@ tnewline(int first_col)
 	int y = term.c.y;
 
 	if (y == term.bot) {
-		tscrollup(term.top, term.bot, 1, SCROLL_SAVEHIST);
+		tscrollup(term.top, 1);
 	} else {
 		y++;
 	}
 	tmoveto(first_col ? 0 : term.c.x, y);
 }
 
-void
-readcolonargs(char **p, int cursor, int params[][CAR_PER_ARG])
-{
-	int i = 0;
-	for (; i < CAR_PER_ARG; i++)
-		params[cursor][i] = -1;
-
-	if (**p != ':')
-		return;
-
-	char *np = NULL;
-	i = 0;
-
-	while (**p == ':' && i < CAR_PER_ARG) {
-		while (**p == ':')
-			(*p)++;
-		params[cursor][i] = strtol(*p, &np, 10);
-		*p = np;
-		i++;
-	}
-}
-
 void
 csiparse(void)
 {
@@ -1451,7 +1149,6 @@ csiparse(void)
 			v = -1;
 		csiescseq.arg[csiescseq.narg++] = v;
 		p = np;
-		readcolonargs(&p, csiescseq.narg-1, csiescseq.carg);
 		if (*p != ';' || csiescseq.narg == ESC_ARG_SIZ)
 			break;
 		p++;
@@ -1518,80 +1215,70 @@ tsetchar(Rune u, const Glyph *attr, int x, int y)
 	term.dirty[y] = 1;
 	term.line[y][x] = *attr;
 	term.line[y][x].u = u;
-        term.line[y][x].mode |= ATTR_SET;
-
-	if (isboxdraw(u))
-		term.line[y][x].mode |= ATTR_BOXDRAW;
 }
 
 void
-tclearglyph(Glyph *gp, int usecurattr)
-{
-      if (usecurattr) {
-            gp->fg = term.c.attr.fg;
-            gp->bg = term.c.attr.bg;
-      } else {
-            gp->fg = defaultfg;
-            gp->bg = defaultbg;
-      }
-      gp->mode =ATTR_NULL;
-      gp->u = ' ';
-}
-
-void
-tclearregion(int x1, int y1, int x2, int y2, int usecurattr)
+tclearregion(int x1, int y1, int x2, int y2)
 {
 	int x, y, temp;
 	Glyph *gp;
 
-        /* regionselected() takes relative coordinates */
-        if (regionselected(x1+term.scr, y1+term.scr, x2+term.scr, y2+term.scr))
-                selremove();
+	if (x1 > x2)
+		temp = x1, x1 = x2, x2 = temp;
+	if (y1 > y2)
+		temp = y1, y1 = y2, y2 = temp;
+
+	LIMIT(x1, 0, term.col-1);
+	LIMIT(x2, 0, term.col-1);
+	LIMIT(y1, 0, term.row-1);
+	LIMIT(y2, 0, term.row-1);
 
 	for (y = y1; y <= y2; y++) {
 		term.dirty[y] = 1;
-                for (x = x1; x <= x2; x++)
-                        tclearglyph(&term.line[y][x], usecurattr);
+		for (x = x1; x <= x2; x++) {
+			gp = &term.line[y][x];
+			if (selected(x, y))
+				selclear();
+			gp->fg = term.c.attr.fg;
+			gp->bg = term.c.attr.bg;
+			gp->mode = 0;
+			gp->u = ' ';
+		}
 	}
 }
 
 void
 tdeletechar(int n)
 {
-        int src, dst, size;
-        Line line;
+	int dst, src, size;
+	Glyph *line;
+
+	LIMIT(n, 0, term.col - term.c.x);
 
-        if (n <= 0)
-                return;
 	dst = term.c.x;
-	src = MIN(term.c.x + n,term.col);
+	src = term.c.x + n;
 	size = term.col - src;
+	line = term.line[term.c.y];
 
-        if (size > 0) { /* otherwise src would point beyond the array
-                           https://stackoverflow.com/questions/29844298 */
-                line = term.line[term.c.y];
-                memmove(&line[dst], &line[src], size * sizeof(Glyph));
-        }
-        tclearregion(dst + size, term.c.y, term.col - 1, term.c.y, 1);
+	memmove(&line[dst], &line[src], size * sizeof(Glyph));
+	tclearregion(term.col-n, term.c.y, term.col-1, term.c.y);
 }
 
 void
 tinsertblank(int n)
 {
-	int src, dst, size;
-	Line line;
+	int dst, src, size;
+	Glyph *line;
+
+	LIMIT(n, 0, term.col - term.c.x);
 
-        if (n <= 0)
-                return;
-        dst= MIN(term.c.x + n, term.col);
+	dst = term.c.x + n;
 	src = term.c.x;
 	size = term.col - dst;
+	line = term.line[term.c.y];
 
-        if (size > 0) { /* otherwise dst would point beyond the array */
-                line = term.line[term.c.y];
-                memmove(&line[dst], &line[src], size * sizeof(Glyph));
-        }
-        tclearregion(src, term.c.y, dst - 1, term.c.y, 1);
+	memmove(&line[dst], &line[src], size * sizeof(Glyph));
+	tclearregion(src, term.c.y, dst - 1, term.c.y);
 }
 
 void
@@ -1605,7 +1292,7 @@ void
 tdeleteline(int n)
 {
 	if (BETWEEN(term.c.y, term.top, term.bot))
-		tscrollup(term.c.y, term.bot, n, SCROLL_NOSAVEHIST);
+		tscrollup(term.c.y, n);
 }
 
 int32_t
@@ -1678,10 +1365,6 @@ tsetattr(const int *attr, int l)
 				ATTR_STRUCK     );
 			term.c.attr.fg = defaultfg;
 			term.c.attr.bg = defaultbg;
-			term.c.attr.ustyle = -1;
-			term.c.attr.ucolor[0] = -1;
-			term.c.attr.ucolor[1] = -1;
-			term.c.attr.ucolor[2] = -1;
 			break;
 		case 1:
 			term.c.attr.mode |= ATTR_BOLD;
@@ -1693,14 +1376,7 @@ tsetattr(const int *attr, int l)
 			term.c.attr.mode |= ATTR_ITALIC;
 			break;
 		case 4:
-			term.c.attr.ustyle = csiescseq.carg[i][0];
-
-			if (term.c.attr.ustyle != 0)
-				term.c.attr.mode |= ATTR_UNDERLINE;
-			else
-				term.c.attr.mode &= ~ATTR_UNDERLINE;
-
-			term.c.attr.mode ^= ATTR_DIRTYUNDERLINE;
+			term.c.attr.mode |= ATTR_UNDERLINE;
 			break;
 		case 5: /* slow blink */
 			/* FALLTHROUGH */
@@ -1751,18 +1427,6 @@ tsetattr(const int *attr, int l)
 		case 49:
 			term.c.attr.bg = defaultbg;
 			break;
-		case 58:
-			term.c.attr.ucolor[0] = csiescseq.carg[i][1];
-			term.c.attr.ucolor[1] = csiescseq.carg[i][2];
-			term.c.attr.ucolor[2] = csiescseq.carg[i][3];
-			term.c.attr.mode ^= ATTR_DIRTYUNDERLINE;
-			break;
-		case 59:
-			term.c.attr.ucolor[0] = -1;
-			term.c.attr.ucolor[1] = -1;
-			term.c.attr.ucolor[2] = -1;
-			term.c.attr.mode ^= ATTR_DIRTYUNDERLINE;
-			break;
 		default:
 			if (BETWEEN(attr[i], 30, 37)) {
 				term.c.attr.fg = attr[i] - 30;
@@ -1802,7 +1466,7 @@ tsetscroll(int t, int b)
 void
 tsetmode(int priv, int set, const int *args, int narg)
 {
-	const int *lim;
+	int alt; const int *lim;
 
 	for (lim = args + narg; args < lim; ++args) {
 		if (priv) {
@@ -1863,18 +1527,25 @@ tsetmode(int priv, int set, const int *args, int narg)
 				xsetmode(set, MODE_8BIT);
 				break;
 			case 1049: /* swap screen & set/restore cursor as xterm */
+				if (!allowaltscreen)
+					break;
+				tcursor((set) ? CURSOR_SAVE : CURSOR_LOAD);
+				/* FALLTHROUGH */
 			case 47: /* swap screen */
-			case 1047: /* swap screen, clearing alternate screen */
+			case 1047:
 				if (!allowaltscreen)
 					break;
-				if (set)
-					tloadaltscreen(*args == 1049, *args == 1049);
-				else
-					tloaddefscreen(*args == 1047, *args == 1049);
-				break;
+				alt = IS_SET(MODE_ALTSCREEN);
+				if (alt) {
+					tclearregion(0, 0, term.col-1,
+							term.row-1);
+				}
+				if (set ^ alt) /* set is always 1 or 0 */
+					tswapscreen();
+				if (*args != 1049)
+					break;
+				/* FALLTHROUGH */
 			case 1048:
-				if (!allowaltscreen)
-          break;
 				tcursor((set) ? CURSOR_SAVE : CURSOR_LOAD);
 				break;
 			case 2004: /* 2004: bracketed paste mode */
@@ -1926,7 +1597,7 @@ void
 csihandle(void)
 {
 	char buf[40];
-	int n, x;
+	int len;
 
 	switch (csiescseq.mode[0]) {
 	default:
@@ -1972,7 +1643,7 @@ csihandle(void)
 			ttywrite(vtiden, strlen(vtiden), 0);
 		break;
 	case 'b': /* REP -- if last char is printable print it <n> more times */
-		DEFAULT(csiescseq.arg[0], 1);
+		LIMIT(csiescseq.arg[0], 1, 65535);
 		if (term.lastc)
 			while (csiescseq.arg[0]-- > 0)
 				tputc(term.lastc);
@@ -2024,31 +1695,20 @@ csihandle(void)
 	case 'J': /* ED -- Clear screen */
 		switch (csiescseq.arg[0]) {
 		case 0: /* below */
-			tclearregion(term.c.x, term.c.y, term.col-1, term.c.y, 1);
+			tclearregion(term.c.x, term.c.y, term.col-1, term.c.y);
 			if (term.c.y < term.row-1) {
-				tclearregion(0, term.c.y+1, term.col-1, term.row-1, 1);
+				tclearregion(0, term.c.y+1, term.col-1,
+						term.row-1);
 			}
 			break;
 		case 1: /* above */
-			if (term.c.y >= 1)
-				tclearregion(0, 0, term.col-1, term.c.y-1, 1);
-			tclearregion(0, term.c.y, term.c.x, term.c.y, 1);
+			if (term.c.y > 1)
+				tclearregion(0, 0, term.col-1, term.c.y-1);
+			tclearregion(0, term.c.y, term.c.x, term.c.y);
 			break;
 		case 2: /* all */
-			if (IS_SET(MODE_ALTSCREEN)) {
-  			tclearregion(0, 0, term.col-1, term.row-1, 1);
-  			break;
-      }
-			/* vte does this:
-			tscrollup(0, term.row-1, term.row, SCROLL_SAVEHIST); */
-      
-			/* alacritty does this: */
-			for (n = term.row-1; n >= 0 && tlinelen(term.line[n]) == 0; n--);
-			if (n >= 0)
-				tscrollup(0, term.row-1, n+1, SCROLL_SAVEHIST);
-			tscrollup(0, term.row-1, term.row-n-1, SCROLL_NOSAVEHIST);
-                        histclean();
-      break;
+			tclearregion(0, 0, term.col-1, term.row-1);
+			break;
 		default:
 			goto unknown;
 		}
@@ -2056,20 +1716,21 @@ csihandle(void)
 	case 'K': /* EL -- Clear line */
 		switch (csiescseq.arg[0]) {
 		case 0: /* right */
-			tclearregion(term.c.x, term.c.y, term.col-1, term.c.y, 1);
+			tclearregion(term.c.x, term.c.y, term.col-1,
+					term.c.y);
 			break;
 		case 1: /* left */
-			tclearregion(0, term.c.y, term.c.x, term.c.y, 1);
+			tclearregion(0, term.c.y, term.c.x, term.c.y);
 			break;
 		case 2: /* all */
-			tclearregion(0, term.c.y, term.col-1, term.c.y, 1);
+			tclearregion(0, term.c.y, term.col-1, term.c.y);
 			break;
 		}
 		break;
 	case 'S': /* SU -- Scroll <n> line up */
+		if (csiescseq.priv) break;
 		DEFAULT(csiescseq.arg[0], 1);
-		/* xterm, urxvt, alacritty save this in history */
-		tscrollup(term.top, term.bot, csiescseq.arg[0], SCROLL_SAVEHIST);
+		tscrollup(term.top, csiescseq.arg[0]);
 		break;
 	case 'T': /* SD -- Scroll <n> line down */
 		DEFAULT(csiescseq.arg[0], 1);
@@ -2087,11 +1748,9 @@ csihandle(void)
 		tdeleteline(csiescseq.arg[0]);
 		break;
 	case 'X': /* ECH -- Erase <n> char */
-		if (csiescseq.arg[0] < 0)
-			return;
 		DEFAULT(csiescseq.arg[0], 1);
-		x = MIN(term.c.x + csiescseq.arg[0], term.col) - 1;
-		tclearregion(term.c.x, term.c.y, x, term.c.y, 1);
+		tclearregion(term.c.x, term.c.y,
+				term.c.x + csiescseq.arg[0] - 1, term.c.y);
 		break;
 	case 'P': /* DCH -- Delete <n> char */
 		DEFAULT(csiescseq.arg[0], 1);
@@ -2111,11 +1770,18 @@ csihandle(void)
 	case 'm': /* SGR -- Terminal attribute (color) */
 		tsetattr(csiescseq.arg, csiescseq.narg);
 		break;
-	case 'n': /* DSR – Device Status Report (cursor position) */
-		if (csiescseq.arg[0] == 6) {
-			n = snprintf(buf, sizeof(buf), "\033[%i;%iR",
-					term.c.y+1, term.c.x+1);
-			ttywrite(buf, n, 0);
+	case 'n': /* DSR -- Device Status Report */
+		switch (csiescseq.arg[0]) {
+		case 5: /* Status Report "OK" `0n` */
+			ttywrite("\033[0n", sizeof("\033[0n") - 1, 0);
+			break;
+		case 6: /* Report Cursor Position (CPR) "<row>;<column>R" */
+			len = snprintf(buf, sizeof(buf), "\033[%i;%iR",
+			               term.c.y+1, term.c.x+1);
+			ttywrite(buf, len, 0);
+			break;
+		default:
+			goto unknown;
 		}
 		break;
 	case 'r': /* DECSTBM -- Set Scrolling Region */
@@ -2144,33 +1810,6 @@ csihandle(void)
 			goto unknown;
 		}
 		break;
-	case 't': /* title stack operations */
-		switch (csiescseq.arg[0]) {
-		case 22: /* pust current title on stack */
-			switch (csiescseq.arg[1]) {
-			case 0:
-			case 1:
-			case 2:
-				xpushtitle();
-				break;
-			default:
-				goto unknown;
-			}
-			break;
-		case 23: /* pop last title from stack */
-			switch (csiescseq.arg[1]) {
-			case 0:
-			case 1:
-			case 2:
-				xsettitle(NULL, 1);
-				break;
-			default:
-				goto unknown;
-			}
-			break;
-		default:
-			goto unknown;
-		}
 	}
 }
 
@@ -2241,30 +1880,29 @@ strhandle(void)
 	};
 
 	term.esc &= ~(ESC_STR_END|ESC_STR);
-        strescseq.buf[strescseq.len] = '\0';
+	strparse();
+	par = (narg = strescseq.narg) ? atoi(strescseq.args[0]) : 0;
 
 	switch (strescseq.type) {
 	case ']': /* OSC -- Operating System Command */
-                strparse();
-                par = (narg = strescseq.narg) ? atoi(STRESCARGJUST(0)) : 0;
 		switch (par) {
 		case 0:
 			if (narg > 1) {
-				xsettitle(STRESCARGREST(1), 0);
-				xseticontitle(STRESCARGREST(1));
+				xsettitle(strescseq.args[1]);
+				xseticontitle(strescseq.args[1]);
 			}
 			return;
 		case 1:
 			if (narg > 1)
-				xseticontitle(STRESCARGREST(1));
+				xseticontitle(strescseq.args[1]);
 			return;
 		case 2:
 			if (narg > 1)
-				xsettitle(STRESCARGREST(1), 0);
+				xsettitle(strescseq.args[1]);
 			return;
 		case 52:
 			if (narg > 2 && allowwindowops) {
-				dec = base64dec(STRESCARGREST(2));
+				dec = base64dec(strescseq.args[2]);
 				if (dec) {
 					xsetsel(dec);
 					xclipcopy();
@@ -2278,7 +1916,7 @@ strhandle(void)
 		case 12:
 			if (narg < 2)
 				break;
-			p = STRESCARGREST(1);
+			p = strescseq.args[1];
 			if ((j = par - 10) < 0 || j >= LEN(osc_table))
 				break; /* shouldn't be possible */
 
@@ -2294,16 +1932,18 @@ strhandle(void)
 		case 4: /* color set */
 			if (narg < 3)
 				break;
-			p = STRESCARGJUST(2);
+			p = strescseq.args[2];
 			/* FALLTHROUGH */
 		case 104: /* color reset */
-			j = (narg > 1) ? atoi(STRESCARGJUST(1)) : -1;
+			j = (narg > 1) ? atoi(strescseq.args[1]) : -1;
 
 			if (p && !strcmp(p, "?")) {
 				osc_color_response(j, 0, 1);
 			} else if (xsetcolorname(j, p)) {
-				if (par == 104 && narg <= 1)
+				if (par == 104 && narg <= 1) {
+					xloadcols();
 					return; /* color reset without parameter */
+				}
 				fprintf(stderr, "erresc: invalid color j=%d, p=%s\n",
 				        j, p ? p : "(null)");
 			} else {
@@ -2317,15 +1957,9 @@ strhandle(void)
 		}
 		break;
 	case 'k': /* old title set compatibility */
-		xsettitle(strescseq.buf, 0);
+		xsettitle(strescseq.args[0]);
 		return;
 	case 'P': /* DCS -- Device Control String */
-		/* https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec */
-		if (strstr(strescseq.buf, "=1s") == strescseq.buf)
-			tsync_begin();  /* BSU */
-		else if (strstr(strescseq.buf, "=2s") == strescseq.buf)
-			tsync_end();  /* ESU */
-		return;
 	case '_': /* APC -- Application Program Command */
 	case '^': /* PM -- Privacy Message */
 		return;
@@ -2342,17 +1976,18 @@ strparse(void)
 	char *p = strescseq.buf;
 
 	strescseq.narg = 0;
+	strescseq.buf[strescseq.len] = '\0';
 
 	if (*p == '\0')
 		return;
 
 	while (strescseq.narg < STR_ARG_SIZ) {
+		strescseq.args[strescseq.narg++] = p;
 		while ((c = *p) != ';' && c != '\0')
-			p++;
-		strescseq.argp[strescseq.narg++] = p;
+			++p;
 		if (c == '\0')
 			return;
-		p++;
+		*p++ = '\0';
 	}
 }
 
@@ -2441,8 +2076,16 @@ tdumpsel(void)
 void
 tdumpline(int n)
 {
-	char str[(term.col + 1) * UTF_SIZ];
-  tprinter(str, tgetline(str, &term.line[n][0]));
+	char buf[UTF_SIZ];
+	const Glyph *bp, *end;
+
+	bp = &term.line[n][0];
+	end = &bp[MIN(tlinelen(n), term.col) - 1];
+	if (bp != end || bp->u != ' ') {
+		for ( ; bp <= end; ++bp)
+			tprinter(buf, utf8encode(bp->u, buf));
+	}
+	tprinter("\n", 1);
 }
 
 void
@@ -2663,7 +2306,7 @@ eschandle(uchar ascii)
 		return 0;
 	case 'D': /* IND -- Linefeed */
 		if (term.c.y == term.bot) {
-			tscrollup(term.top, term.bot, 1, SCROLL_SAVEHIST);
+			tscrollup(term.top, 1);
 		} else {
 			tmoveto(term.c.x, term.c.y+1);
 		}
@@ -2686,9 +2329,9 @@ eschandle(uchar ascii)
 		break;
 	case 'c': /* RIS -- Reset to initial state */
 		treset();
-		xfreetitlestack();
 		resettitle();
 		xloadcols();
+		xsetmode(0, MODE_HIDE);
 		break;
 	case '=': /* DECPAM -- Application keypad */
 		xsetmode(1, MODE_APPKEYPAD);
@@ -2781,6 +2424,9 @@ check_control_code:
 	 * they must not cause conflicts with sequences.
 	 */
 	if (control) {
+		/* in UTF-8 mode ignore handling C1 control characters */
+		if (IS_SET(MODE_UTF8) && ISCONTROLC1(u))
+			return;
 		tcontrolcode(u);
 		/*
 		 * control codes are not shown ever
@@ -2817,8 +2463,7 @@ check_control_code:
 		 */
 		return;
 	}
-	/* selected() takes relative coordinates */
-	if (selected(term.c.x + term.scr, term.c.y + term.scr))
+	if (selected(term.c.x, term.c.y))
 		selclear();
 
 	gp = &term.line[term.c.y][term.c.x];
@@ -2828,11 +2473,16 @@ check_control_code:
 		gp = &term.line[term.c.y][term.c.x];
 	}
 
-	if (IS_SET(MODE_INSERT) && term.c.x+width < term.col)
+	if (IS_SET(MODE_INSERT) && term.c.x+width < term.col) {
 		memmove(gp+width, gp, (term.col - term.c.x - width) * sizeof(Glyph));
+		gp->mode &= ~ATTR_WIDE;
+	}
 
 	if (term.c.x+width > term.col) {
-		tnewline(1);
+		if (IS_SET(MODE_WRAP))
+			tnewline(1);
+		else
+			tmoveto(term.col - width, term.c.y);
 		gp = &term.line[term.c.y][term.c.x];
 	}
 
@@ -2853,7 +2503,6 @@ check_control_code:
 	if (term.c.x+width < term.col) {
 		tmoveto(term.c.x+width, term.c.y);
 	} else {
-		term.wrapcwidth[IS_SET(MODE_ALTSCREEN)] = width;
 		term.c.state |= CURSOR_WRAPNEXT;
 	}
 }
@@ -2865,9 +2514,6 @@ twrite(const char *buf, int buflen, int show_ctrl)
 	Rune u;
 	int n;
 
-	int su0 = su;
-	twrite_aborted = 0;
-
 	for (n = 0; n < buflen; n += charsize) {
 		if (IS_SET(MODE_UTF8)) {
 			/* process a complete utf8 char */
@@ -2878,10 +2524,6 @@ twrite(const char *buf, int buflen, int show_ctrl)
 			u = buf[n] & 0xFF;
 			charsize = 1;
 		}
-		if (su0 && !su) {
-			twrite_aborted = 1;
-			break;  // ESU - allow rendering before a new BSU
-		}
 		if (show_ctrl && ISCONTROL(u)) {
 			if (u & 0x80) {
 				u &= 0x7f;
@@ -2897,282 +2539,92 @@ twrite(const char *buf, int buflen, int show_ctrl)
 	return n;
 }
 
-void
-treflow(int col, int row)
-{
-	int i, j;
-	int oce, nce, bot, scr;
-	int ox = 0, oy = -term.histf, nx = 0, ny = -1, len;
-	int cy = -1; /* proxy for new y coordinate of cursor */
-	int nlines;
-	Line *buf, line;
-
-	/* y coordinate of cursor line end */
-	for (oce = term.c.y; oce < term.row - 1 &&
-	                     tiswrapped(term.line[oce]); oce++);
-
-	nlines = term.histf + oce + 1;
-	if (col < term.col) {
-		/* each line can take this many lines after reflow */
-		j = (term.col + col - 1) / col;
-		nlines = j * nlines;
-		if (nlines > HISTSIZE + RESIZEBUFFER + row) {
-			nlines = HISTSIZE + RESIZEBUFFER + row;
-			oy = -(nlines / j - oce - 1);
-		}
-	}
-	buf = xmalloc(nlines * sizeof(Line));
-	do {
-		if (!nx)
-			buf[++ny] = xmalloc(col * sizeof(Glyph));
-		if (!ox) {
-			line = TLINEABS(oy);
-			len = tlinelen(line);
-		}
-		if (oy == term.c.y) {
-			if (!ox)
-				len = MAX(len, term.c.x + 1);
-			/* update cursor */
-			if (cy < 0 && term.c.x - ox < col - nx) {
-				term.c.x = nx + term.c.x - ox, cy = ny;
-				UPDATEWRAPNEXT(0, col);
-			}
-		}
-		/* get reflowed lines in buf */
-		if (col - nx > len - ox) {
-			memcpy(&buf[ny][nx], &line[ox], (len-ox) * sizeof(Glyph));
-			nx += len - ox;
-			if (len == 0 || !(line[len - 1].mode & ATTR_WRAP)) {
-				for (j = nx; j < col; j++)
-					tclearglyph(&buf[ny][j], 0);
-				nx = 0;
-			} else if (nx > 0) {
-				buf[ny][nx - 1].mode &= ~ATTR_WRAP;
-			}
-			ox = 0, oy++;
-		} else if (col - nx == len - ox) {
-			memcpy(&buf[ny][nx], &line[ox], (col-nx) * sizeof(Glyph));
-			ox = 0, oy++, nx = 0;
-		} else/* if (col - nx < len - ox) */ {
-			memcpy(&buf[ny][nx], &line[ox], (col-nx) * sizeof(Glyph));
-    	ox += col - nx;
-			buf[ny][col - 1].mode |= ATTR_WRAP;
-			nx = 0;
-		}
-	} while (oy <= oce);
-	if (nx)
-		for (j = nx; j < col; j++)
-			tclearglyph(&buf[ny][j], 0);
-
-	/* free extra lines */
-	for (i = row; i < term.row; i++)
-		free(term.line[i]);
-	/* resize to new height */
-	term.line = xrealloc(term.line, row * sizeof(Line));
-
-	bot = MIN(ny, row - 1);
-	scr = MAX(row - term.row, 0);
-	/* update y coordinate of cursor line end */
-	nce = MIN(oce + scr, bot);
-	/* update cursor y coordinate */
-	term.c.y = nce - (ny - cy);
-	if (term.c.y < 0) {
-		j = nce, nce = MIN(nce + -term.c.y, bot);
-		term.c.y += nce - j;
-		while (term.c.y < 0) {
-			free(buf[ny--]);
-			term.c.y++;
-		}
-	}
-	/* allocate new rows */
-	for (i = row - 1; i > nce; i--) {
-		term.line[i] = xmalloc(col * sizeof(Glyph));
-		for (j = 0; j < col; j++)
-			tclearglyph(&term.line[i][j], 0);
-	}
-	/* fill visible area */
-	for (/*i = nce */; i >= term.row; i--, ny--)
-		term.line[i] = buf[ny];
-	for (/*i = term.row - 1 */; i >= 0; i--, ny--) {
-		free(term.line[i]);
-		term.line[i] = buf[ny];
-	}
-	/* fill lines in history buffer and update term.histf */
-	for (/*i = -1 */; ny >= 0 && i >= -HISTSIZE; i--, ny--) {
-		j = (term.histi + i + 1 + HISTSIZE) % HISTSIZE;
-		free(term.hist[j]);
-		term.hist[j] = buf[ny];
-	}
-	term.histf = -i - 1;
-	term.scr = MIN(term.scr, term.histf);
-	/* resize rest of the history lines */
-	for (/*i = -term.histf - 1 */; i >= -HISTSIZE; i--) {
-		j = (term.histi + i + 1 + HISTSIZE) % HISTSIZE;
-		term.hist[j] = xrealloc(term.hist[j], col * sizeof(Glyph));
-	}
-	free(buf);
-}
-
-void
-rscrolldown(int n)
-{
-	int i;
-	Line temp;
-
-	/* can never be true as of now
-	if (IS_SET(MODE_ALTSCREEN))
-		return; */
-
-	if ((n = MIN(n, term.histf)) <= 0)
-		return;
-
-	for (i = term.c.y + n; i >= n; i--) {
-		temp = term.line[i];
-		term.line[i] = term.line[i-n];
-		term.line[i-n] = temp;
-	}
-	for (/*i = n - 1 */; i >= 0; i--) {
-		temp = term.line[i];
-		term.line[i] = term.hist[term.histi];
-		term.hist[term.histi] = temp;
-		term.histi = (term.histi - 1 + HISTSIZE) % HISTSIZE;
-	}
-	term.c.y += n;
-	term.histf -= n;
-	if ((i = term.scr - n) >= 0) {
-		term.scr = i;
-	} else {
-		term.scr = 0;
-		if (sel.ob.x != -1 && !sel.alt)
-			selmove(-i);
-	}
-}
-
 void
 tresize(int col, int row)
 {
+	int i;
+	int minrow = MIN(row, term.row);
+	int mincol = MIN(col, term.col);
 	int *bp;
+	TCursor c;
 
-	/* col and row are always MAX(_, 1)
 	if (col < 1 || row < 1) {
-		fprintf(stderr, "tresize: error resizing to %dx%d\n", col, row);
-		return;
-	} */
-
-	term.dirty = xrealloc(term.dirty, row * sizeof(*term.dirty));
-	term.tabs = xrealloc(term.tabs, col * sizeof(*term.tabs));
-	if (col > term.col) {
-		bp = term.tabs + term.col;
-		memset(bp, 0, sizeof(*term.tabs) * (col - term.col));
-		while (--bp > term.tabs && !*bp)
-			/* nothing */ ;
-		for (bp += tabspaces; bp < term.tabs + col; bp += tabspaces)
-			*bp = 1;
-	}
-
-	if (IS_SET(MODE_ALTSCREEN))
-		tresizealt(col, row);
-	else
-		tresizedef(col, row);
-}
-
-void
-tresizedef(int col, int row)
-{
-	int i, j;
-
-	/* return if dimensions haven't changed */
-	if (term.col == col && term.row == row) {
-		tfulldirt();
+		fprintf(stderr,
+		        "tresize: error resizing to %dx%d\n", col, row);
 		return;
 	}
-	if (col != term.col) {
-		if (!sel.alt)
-			selremove();
-		treflow(col, row);
-	} else {
-		/* slide screen up if otherwise cursor would get out of the screen */
-		if (term.c.y >= row) {
-			tscrollup(0, term.row - 1, term.c.y - row + 1, SCROLL_RESIZE);
-			term.c.y = row - 1;
-		}
-		for (i = row; i < term.row; i++)
-			free(term.line[i]);
-
-		/* resize to new height */
-		term.line = xrealloc(term.line, row * sizeof(Line));
-		/* allocate any new rows */
-		for (i = term.row; i < row; i++) {
-			term.line[i] = xmalloc(col * sizeof(Glyph));
-			for (j = 0; j < col; j++)
-				tclearglyph(&term.line[i][j], 0);
-		}
-		/* scroll down as much as height has increased */
-		rscrolldown(row - term.row);
-	}
-	/* update terminal size */
-	term.col = col, term.row = row;
-	/* reset scrolling region */
-	term.top = 0, term.bot = row - 1;
-	/* dirty all lines */
-	tfulldirt();
-}
 
-void
-tresizealt(int col, int row)
-{
-	int i, j;
-
-	/* return if dimensions haven't changed */
-	if (term.col == col && term.row == row) {
-		tfulldirt();
-		return;
-	}
-	if (sel.alt)
-		selremove();
-	/* slide screen up if otherwise cursor would get out of the screen */
-	for (i = 0; i <= term.c.y - row; i++)
+	/*
+	 * slide screen to keep cursor where we expect it -
+	 * tscrollup would work here, but we can optimize to
+	 * memmove because we're freeing the earlier lines
+	 */
+	for (i = 0; i <= term.c.y - row; i++) {
 		free(term.line[i]);
+		free(term.alt[i]);
+	}
+	/* ensure that both src and dst are not NULL */
 	if (i > 0) {
-		/* ensure that both src and dst are not NULL */
 		memmove(term.line, term.line + i, row * sizeof(Line));
-		term.c.y = row - 1;
+		memmove(term.alt, term.alt + i, row * sizeof(Line));
 	}
-	for (i += row; i < term.row; i++)
+	for (i += row; i < term.row; i++) {
 		free(term.line[i]);
+		free(term.alt[i]);
+	}
+
 	/* resize to new height */
 	term.line = xrealloc(term.line, row * sizeof(Line));
-	/* resize to new width */
-	for (i = 0; i < MIN(row, term.row); i++) {
+	term.alt  = xrealloc(term.alt,  row * sizeof(Line));
+	term.dirty = xrealloc(term.dirty, row * sizeof(*term.dirty));
+	term.tabs = xrealloc(term.tabs, col * sizeof(*term.tabs));
+
+	/* resize each row to new width, zero-pad if needed */
+	for (i = 0; i < minrow; i++) {
 		term.line[i] = xrealloc(term.line[i], col * sizeof(Glyph));
-		for (j = term.col; j < col; j++)
-			tclearglyph(&term.line[i][j], 0);
+		term.alt[i]  = xrealloc(term.alt[i],  col * sizeof(Glyph));
 	}
+
 	/* allocate any new rows */
-	for (/*i = MIN(row, term.row) */; i < row; i++) {
+	for (/* i = minrow */; i < row; i++) {
 		term.line[i] = xmalloc(col * sizeof(Glyph));
-		for (j = 0; j < col; j++)
-			tclearglyph(&term.line[i][j], 0);
+		term.alt[i] = xmalloc(col * sizeof(Glyph));
 	}
-	/* update cursor */
-	if (term.c.x >= col) {
-		term.c.state &= ~CURSOR_WRAPNEXT;
-		term.c.x = col - 1;
-	} else {
-		UPDATEWRAPNEXT(1, col);
+	if (col > term.col) {
+		bp = term.tabs + term.col;
+
+		memset(bp, 0, sizeof(*term.tabs) * (col - term.col));
+		while (--bp > term.tabs && !*bp)
+			/* nothing */ ;
+		for (bp += tabspaces; bp < term.tabs + col; bp += tabspaces)
+			*bp = 1;
 	}
 	/* update terminal size */
-	term.col = col, term.row = row;
+	term.col = col;
+	term.row = row;
 	/* reset scrolling region */
-	term.top = 0, term.bot = row - 1;
-	/* dirty all lines */
-	tfulldirt();
+	tsetscroll(0, row-1);
+	/* make use of the LIMIT in tmoveto */
+	tmoveto(term.c.x, term.c.y);
+	/* Clearing both screens (it makes dirty all lines) */
+	c = term.c;
+	for (i = 0; i < 2; i++) {
+		if (mincol < col && 0 < minrow) {
+			tclearregion(mincol, 0, col - 1, minrow - 1);
+		}
+		if (0 < col && minrow < row) {
+			tclearregion(0, minrow, col - 1, row - 1);
+		}
+		tswapscreen();
+		tcursor(CURSOR_LOAD);
+	}
+	term.c = c;
 }
 
 void
 resettitle(void)
 {
-	xsettitle(NULL, 0);
+	xsettitle(NULL);
 }
 
 void
@@ -3185,7 +2637,7 @@ drawregion(int x1, int y1, int x2, int y2)
 			continue;
 
 		term.dirty[y] = 0;
-		xdrawline(TLINE(y), x1, y, x2);
+		xdrawline(term.line[y], x1, y, x2);
 	}
 }
 
@@ -3221,90 +2673,3 @@ redraw(void)
 	tfulldirt();
 	draw();
 }
-
-int
-daddch(URLdfa *dfa, char c)
-{
-	/* () and [] can appear in urls, but excluding them here will reduce false
-	 * positives when figuring out where a given url ends.
-	 */
-	static const char URLCHARS[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-		"abcdefghijklmnopqrstuvwxyz"
-		"0123456789-._~:/?#@!$&'*+,;=%";
-	static const char RPFX[] = "//:sptth";
-
-	if (!strchr(URLCHARS, c)) {
-		dfa->length = 0;
-		dfa->state = 0;
-
-		return 0;
-	}
-
-	dfa->length++;
-
-	if (dfa->state == 2 && c == '/') {
-		dfa->state = 0;
-	} else if (dfa->state == 3 && c == 'p') {
-		dfa->state++;
-	} else if (c != RPFX[dfa->state]) {
-		dfa->state = 0;
-		return 0;
-	}
-
-	if (dfa->state++ == 7) {
-		dfa->state = 0;
-		return 1;
-	}
-
-	return 0;
-}
-
-/*
-** Select and copy the previous url on screen (do nothing if there's no url).
-*/
-void
-copyurl(const Arg *arg) {
-	int row = 0, /* row of current URL */
-		col = 0, /* column of current URL start */
-		colend = 0, /* column of last occurrence */
-		passes = 0; /* how many rows have been scanned */
-
-	const char *c = NULL,
-		 *match = NULL;
-	URLdfa dfa = { 0 };
-
-	row = (sel.ob.x >= 0 && sel.nb.y > 0) ? sel.nb.y : term.bot;
-	LIMIT(row, term.top, term.bot);
-
-	colend = (sel.ob.x >= 0 && sel.nb.y > 0) ? sel.nb.x : term.col;
-	LIMIT(colend, 0, term.col);
-
-	/*
-	** Scan from (term.row - 1,term.col - 1) to (0,0) and find
-	** next occurrance of a URL
-	*/
-	for (passes = 0; passes < term.row; passes++) {
-		/* Read in each column of every row until
-		** we hit previous occurrence of URL
-		*/
-		for (col = colend; col--;)
-			if (daddch(&dfa, term.line[row][col].u < 128 ? term.line[row][col].u : ' '))
-				break;
-
-		if (col >= 0)
-			break;
-
-		if (--row < 0)
-			row = term.row - 1;
-
-		colend = term.col;
-	}
-
-	if (passes < term.row) {
-		selstart(col, row, 0);
-		selextend((col + dfa.length - 1) % term.col, row + (col + dfa.length - 1) / term.col, SEL_REGULAR, 0);
-		selextend((col + dfa.length - 1) % term.col, row + (col + dfa.length - 1) / term.col, SEL_REGULAR, 1);
-		xsetsel(getsel());
-		xclipcopy();
-	}
-}
-- 
cgit v1.2.3