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kilo/kilo.c
Hadeed Ahmad 9ebd31095c Finish chapter 3
Left reading of some terminal codes that I don't think I'll need
2023-08-24 21:16:36 +05:00

242 lines
4.9 KiB
C

#include <ctype.h>
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <termios.h>
#include <unistd.h>
struct abuf {
char *p;
int len;
};
struct {
struct termios orig_termios;
int rows;
int cols;
int cx, cy;
} E = { .cx = 0, .cy = 0 };
enum keys {
ARROW_UP = 0x100 + 1,
ARROW_DOWN,
ARROW_LEFT,
ARROW_RIGHT
};
#define ABUF_INIT {NULL, 0}
void ab_append(struct abuf *, const char *);
void ab_free(struct abuf *);
void ab_write(struct abuf *);
void enable_raw_mode();
void disable_raw_mode();
int get_window_size(int *, int *);
int read_cursor_position(int *, int *);
void editor_init();
void editor_redraw_screen();
void editor_clear_screen();
void editor_draw_rows(struct abuf *);
void editor_process_key();
int editor_read_key();
void die(const char *);
#define CTRL_KEY(key) ((key) & 0x1f)
int main() {
editor_init();
while (1) {
editor_redraw_screen();
editor_process_key();
}
return 0;
}
void editor_init() {
if (!isatty(STDIN_FILENO)) {
printf("kilo only supports a terminal at standard in. Exiting.");
exit(1);
}
enable_raw_mode();
if (get_window_size(&E.rows, &E.cols) == -1) die("get_window_size");
}
void enable_raw_mode() {
if (tcgetattr(STDIN_FILENO, &E.orig_termios) == -1) die("tcgetattr");
atexit(disable_raw_mode);
struct termios raw = E.orig_termios;
cfmakeraw(&raw);
raw.c_cc[VMIN] = 0;
raw.c_cc[VTIME] = 1;
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1) die("tcsetattr");
}
void disable_raw_mode() {
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == -1)
die("tcsetattr");
}
int get_window_size(int *rows, int *cols) {
struct winsize ws;
if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) != -1 && ws.ws_col != 0) {
*rows = ws.ws_row;
*cols = ws.ws_col;
return 0;
} else {
if (write(STDOUT_FILENO, "\x1b[999C\x1b[999B", 12) != 12) return -1;
return read_cursor_position(rows, cols);
}
return -1;
}
int read_cursor_position(int *rows, int *cols) {
char buf[32];
int i = 0;
if (write(STDOUT_FILENO, "\x1b[6n", 4) != 4) return -1;
if (read(STDIN_FILENO, buf, 1) != 1 && *buf != '\x1b') return -1;
if (read(STDIN_FILENO, buf, 1) != 1 && *buf != '[') return -1;
do {
if (i == (int) sizeof(buf)) return -1;
if (read(STDIN_FILENO, buf+i, 1) == 0) break;
} while(buf[i++] != 'R');
buf[i-1] = '\0';
if (sscanf(buf, "%d;%d", rows, cols) != 2) return -1;
return 0;
}
void editor_redraw_screen() {
struct abuf ab = ABUF_INIT;
ab_append(&ab, "\x1b[?25l");
ab_append(&ab, "\x1b[H");
editor_draw_rows(&ab);
char buf[32];
snprintf(buf, sizeof(buf), "\x1b[%d;%dH", E.cy + 1, E.cx + 1);
ab_append(&ab, buf);
ab_append(&ab, "\x1b[?25h");
ab_write(&ab);
ab_free(&ab);
}
void editor_clear_screen() {
write(STDOUT_FILENO, "\x1b[2J", 4);
write(STDOUT_FILENO, "\x1b[H", 3);
}
void editor_draw_rows(struct abuf *ab) {
for (int y = 0; y < E.rows; y++) {
ab_append(ab, "~");
ab_append(ab, "\x1b[K");
if (y < E.rows - 1) ab_append(ab, "\r\n");
}
}
void editor_process_key() {
int c = editor_read_key();
switch (c) {
case CTRL_KEY('Q'):
editor_clear_screen();
exit(0);
break;
case ARROW_LEFT:
if (E.cx > 0) E.cx--;
break;
case ARROW_DOWN:
if (E.cy < E.rows - 1) E.cy++;
break;
case ARROW_UP:
if (E.cy > 0) E.cy--;
break;
case ARROW_RIGHT:
if (E.cx < E.cols - 1) E.cx++;
break;
default:
printf("%d\r\n", c);
break;
}
}
int editor_read_key() {
char c;
while (read(STDIN_FILENO, &c, 1) == 0);
if (c == '\x1b') {
char buf[2];
if (read(STDIN_FILENO, buf+0, 1) != 1) return c;
if (read(STDIN_FILENO, buf+1, 1) != 1) return c;
if (buf[0] == '[') {
switch (buf[1]) {
case 'A':
return ARROW_UP;
break;
case 'B':
return ARROW_DOWN;
break;
case 'C':
return ARROW_RIGHT;
break;
case 'D':
return ARROW_LEFT;
break;
}
}
}
return (int) c;
}
void die(const char *s) {
editor_clear_screen();
perror(s);
exit(1);
}
void ab_append(struct abuf *ab, const char *s) {
int len = strlen(s);
ab->p = realloc(ab->p, ab->len + len);
memcpy(ab->p + ab->len, s, len);
ab->len += len;
}
void ab_write(struct abuf *ab) {
write(STDOUT_FILENO, ab->p, ab->len);
}
void ab_free(struct abuf *ab) {
free(ab->p);
}