kst/ke/main.c

278 lines
4.1 KiB
C
Raw Normal View History

2020-02-08 08:40:21 +00:00
#include <sys/ioctl.h>
#include <ctype.h>
2020-02-08 07:07:59 +00:00
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
2020-02-08 08:40:21 +00:00
#include <string.h>
#include <termios.h>
#include <unistd.h>
2020-02-08 08:40:21 +00:00
#define ESCSEQ "\x1b["
#define CTRL_KEY(key) ((key)&0x1f)
/*
* define the keyboard input modes
* normal: no special mode
* kcommand: ^k commands
*/
#define MODE_NORMAL 0
#define MODE_KCOMMAND 1
struct {
struct termios entry_term;
int rows, cols;
} editor;
/* append buffer */
struct abuf {
char *b;
int len;
};
#define ABUF_INIT {NULL, 0}
void
ab_append(struct abuf *buf, const char *s, int len)
{
char *nc = realloc(buf->b, buf->len + len);
if (nc == NULL) {
return;
}
memcpy(&nc[buf->len], s, len);
buf->b = nc;
buf->len += len; /* DANGER: overflow */
}
void
ab_free(struct abuf *buf)
{
free(buf->b);
}
void
die(const char *s)
{
/*
* NOTE(kyle): this is a duplication of the code in display.c
* but I would like to be able to import these files from there.
*/
write(STDOUT_FILENO, "\x1b[2J", 4);
write(STDOUT_FILENO, "\x1b[H", 3);
perror(s);
exit(1);
}
/*
* get_winsz uses the TIOCGWINSZ to get the window size.
*
* there's a fallback way to do this, too, that involves moving the
* cursor down and to the left \x1b[999C\x1b[999B. I'm going to skip
* on this for now because it's bloaty and this works on OpenBSD and
* Linux, at least.
*/
int
get_winsz(int *rows, int *cols)
{
struct winsize ws;
if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 ||
ws.ws_col == 0) {
return -1;
}
*cols = ws.ws_col;
*rows = ws.ws_row;
return 0;
}
static char
get_keypress()
{
char c = 0;
if (read(STDIN_FILENO, &c, 1) == -1) {
die("get_keypress:read");
}
return c;
}
void
process_keypress()
{
static int m = MODE_NORMAL;
char c = get_keypress();
if (c == 0x0) {
return;
}
switch (m) {
case MODE_KCOMMAND:
switch (c) {
case 'q':
case CTRL_KEY('q'):
exit(0);
}
m = MODE_NORMAL;
return;
}
if (c == CTRL_KEY('k')) {
m = MODE_KCOMMAND;
return;
}
}
/*
* A text editor needs the terminal to be in raw mode; but the default
* is to be in canonical (cooked) mode, which is a buffered input mode.
*/
static void
enable_termraw()
{
struct termios raw;
/* Read the current terminal parameters for standard input. */
if (tcgetattr(STDIN_FILENO, &raw) == -1) {
die("tcgetattr while enabling raw mode");
}
/*
* Put the terminal into raw mode.
*/
cfmakeraw(&raw);
/*
* Set timeout for read(2).
*
* VMIN: what is the minimum number of bytes required for read
* to return?
*
* VTIME: max time before read(2) returns in hundreds of milli-
* seconds.
*/
raw.c_cc[VMIN] = 0;
raw.c_cc[VTIME] = 1;
/*
* Now write the terminal parameters to the current terminal,
* after flushing any waiting input out.
*/
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1) {
die("tcsetattr while enabling raw mode");
}
}
static void
disable_termraw()
{
display_clear(NULL);
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &editor.entry_term) == -1) {
die("couldn't disable terminal raw mode");
}
}
void
setup_terminal()
{
if (tcgetattr(STDIN_FILENO, &editor.entry_term) == -1) {
die("can't snapshot terminal settings");
}
atexit(disable_termraw);
enable_termraw();
}
void
display_clear(struct abuf *ab)
{
if (ab == NULL) {
write(STDOUT_FILENO, ESCSEQ "2J", 4);
write(STDOUT_FILENO, ESCSEQ "H", 3);
} else {
ab_append(ab, ESCSEQ "2J", 4);
ab_append(ab, ESCSEQ "H", 3);
}
}
void
draw_rows(struct abuf *ab)
{
int y;
for (y = 0; y < editor.rows-1; y++) {
ab_append(ab, "|\r\n", 3);
}
ab_append(ab, "|", 1);
}
void
display_refresh()
{
struct abuf ab = ABUF_INIT;
ab_append(&ab, ESCSEQ "?25l", 6);
display_clear(&ab);
draw_rows(&ab);
ab_append(&ab, ESCSEQ "1;2H", 7);
ab_append(&ab, ESCSEQ "?25h", 6);
write(STDOUT_FILENO, ab.b, ab.len);
ab_free(&ab);
}
2020-02-08 07:07:59 +00:00
void
loop()
{
2020-02-08 07:07:59 +00:00
while (1) {
2020-02-08 08:40:21 +00:00
display_refresh();
process_keypress();
2020-02-08 07:07:59 +00:00
}
}
2020-02-08 08:40:21 +00:00
/*
* init_editor should set up the global editor struct.
*/
void
init_editor()
{
if (get_winsz(&editor.rows, &editor.cols) == -1) {
die("can't get window size");
}
}
int
main()
{
2020-02-08 07:07:59 +00:00
setup_terminal();
2020-02-08 08:40:21 +00:00
init_editor();
2020-02-08 08:40:21 +00:00
display_clear(NULL);
2020-02-08 07:07:59 +00:00
loop();
return 0;
}