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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "dsp/tty/itoa8.h"
#include "dsp/tty/tty.h"
#include "libc/bits/safemacros.h"
#include "libc/limits.h"
#include "libc/log/check.h"
/**
* Moves teletypewriter cursor to new coordinate.
*
* This uses codings defined by ANSI X3.4-1967 / X3.64-1979.
*
* @param c [in/out] tracks cursor coordinate
* @param p [out] buffer receives ANSI/VT sequences
* @param y is 0-indexed row
* @param x is 0-indexed column
* @return p + written, like mempcpy()
*/
char *ttymove(struct TtyCursor *c, char *p, int y, int x) {
int d;
DCHECK_GE(y, 0);
DCHECK_GE(x, 0);
DCHECK_LE(y, UINT16_MAX);
DCHECK_LE(x, UINT16_MAX);
if (y != c->y || x != c->x) {
do {
if (y != c->y && x != c->x) {
if (y == c->y + 1 && x == 0) {
p[0] = '\r';
p[1] = '\n';
p[2] = '\0';
p[3] = '\0';
p += 2;
c->y++;
c->x = 0;
break;
} else if (x < 256 && y < 256) {
if (y == 0 && x == 0) {
if (c->y == 0) {
p[0] = '\r';
p[1] = '\0';
p += 1;
c->x = 0;
} else {
p[0] = '\e'; /* CUP(1,1) */
p[1] = '[';
p[2] = 'H';
p[3] = '\0';
p += 3;
c->y = 0;
c->x = 0;
}
} else if (x == 0) {
*p++ = '\e'; /* CUP(y,1) */
*p++ = '[';
p = itoa8(p, y + 1);
*p++ = 'H';
*p = '\0';
c->y = y;
c->x = 0;
} else if (y == 0) {
*p++ = '\e'; /* CUP(1,x) */
*p++ = '[';
*p++ = ';';
*p = '\0';
p = itoa8(p, x + 1);
*p++ = 'H';
*p = '\0';
c->y = 0;
c->x = x;
} else {
*p++ = '\e'; /* CUP(y,1) */
*p++ = '[';
p = itoa8(p, y + 1);
*p++ = ';';
p = itoa8(p, x + 1);
*p++ = 'H';
*p = '\0';
c->y = y;
c->x = x;
}
break;
}
}
if (x != c->x) {
if (!x) {
p[0] = '\r'; /* goto beginning of line */
p[1] = '\0';
p += 1;
c->x = 0;
} else if (x > c->x) {
d = min(255, x - c->x);
if (d == 1) {
p[0] = '\e';
p[1] = '[';
p[2] = 'C'; /* cursor forward (CUF) */
p[3] = '\0';
p += 3;
} else {
p[0] = '\e';
p[1] = '[';
p = itoa8(p + 2, d);
p[0] = 'C'; /* cursor forward (CUF) */
p[1] = '\0';
p[2] = '\0';
p[3] = '\0';
p += 1;
}
c->x += d;
} else {
d = min(255, c->x - x);
if (d == 1) {
p[0] = '\e';
p[1] = '[';
p[2] = 'D'; /* cursor backward (CUB) */
p[3] = '\0';
p += 3;
} else {
p[0] = '\e';
p[1] = '[';
p = itoa8(p + 2, d);
p[0] = 'D'; /* cursor backward (CUB) */
p[1] = '\0';
p[2] = '\0';
p[3] = '\0';
p += 1;
}
c->x -= d;
}
}
if (y != c->y) {
if (y > c->y) {
d = min(255, y - c->y);
if (d == 1) {
p[0] = '\e';
p[1] = 'D'; /* index down (IND) */
p[2] = '\0';
p[3] = '\0';
p += 2;
} else {
p[0] = '\e';
p[1] = '[';
p = itoa8(p + 2, d);
p[0] = 'B'; /* cursor down (CUD) */
p[1] = '\0';
p[2] = '\0';
p[3] = '\0';
p += 1;
}
c->y += d;
} else {
d = min(255, c->y - y);
if (d == 1) {
p[0] = '\e';
p[1] = 'M'; /* reverse index (RI) */
p[2] = '\0';
p[3] = '\0';
p += 2;
} else {
p[0] = '\e';
p[1] = '[';
p = itoa8(p + 2, d);
p[0] = 'A'; /* cursor up (CUU) */
p[1] = '\0';
p[2] = '\0';
p[3] = '\0';
p += 1;
}
c->y -= d;
}
}
} while (x != c->x || y != c->y);
} else {
p[0] = '\0';
}
DCHECK_EQ(y, c->y);
DCHECK_EQ(x, c->x);
DCHECK_EQ(p[0], '\0');
return p;
}