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/*** includes ***/
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <termios.h>
#include <unistd.h>
/*** defines ***/
#define KILO_VERSION "0.0.1"
#define CTRL_KEY(k) ((k)&0x1f)
enum editorKey {
ARROW_LEFT = 1000,
ARROW_RIGHT,
ARROW_UP,
ARROW_DOWN,
DEL_KEY,
HOME_KEY,
END_KEY,
PAGE_UP,
PAGE_DOWN
};
/*** data ***/
struct editorConfig {
int cx, cy;
int screenrows;
int screencols;
struct termios orig_termios;
};
struct editorConfig E;
/*** terminal ***/
void die(const char *s) {
write(STDOUT_FILENO, "\x1b[2J", 4); // clear whole screen
write(STDOUT_FILENO, "\x1b[H", 3); // move cursor to top-left
perror(s);
exit(1);
}
void disableRawMode() {
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == -1)
die("tcsetattr");
}
void enableRawMode() {
if (tcgetattr(STDIN_FILENO, &E.orig_termios) == -1)
die("tcgetattr");
atexit(disableRawMode);
struct termios raw = E.orig_termios;
raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
raw.c_oflag &= ~(OPOST);
raw.c_cflag |= (CS8);
raw.c_lflag &= ~(ECHO | ICANON | IEXTEN | ISIG);
raw.c_cc[VMIN] = 0;
raw.c_cc[VTIME] = 1;
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1)
die("tcsetattr");
}
int editorReadKey() {
int nread;
char c;
while ((nread = read(STDIN_FILENO, &c, 1)) != 1) {
if (nread == -1 && errno != EAGAIN)
die("read");
}
if (c == '\x1b') {
char seq[3];
if (read(STDIN_FILENO, &seq[0], 1) != 1)
return '\x1b';
if (read(STDIN_FILENO, &seq[1], 1) != 1)
return '\x1b';
if (seq[0] == '[') {
if (seq[1] >= '0' && seq[1] <= '9') {
if (read(STDIN_FILENO, &seq[2], 1) != 1)
return '\x1b';
if (seq[2] == '~') {
switch (seq[1]) {
case '1':
return HOME_KEY;
case '3':
return DEL_KEY;
case '4':
return END_KEY;
case '5':
return PAGE_UP;
case '6':
return PAGE_DOWN;
case '7':
return HOME_KEY;
case '8':
return END_KEY;
}
}
} else {
switch (seq[1]) {
case 'A':
return ARROW_UP;
case 'B':
return ARROW_DOWN;
case 'C':
return ARROW_RIGHT;
case 'D':
return ARROW_LEFT;
case 'H':
return HOME_KEY;
case 'F':
return END_KEY;
}
}
} else if (seq[0] == 'O') {
switch (seq[1]) {
case 'H':
return HOME_KEY;
case 'F':
return END_KEY;
}
}
return '\x1b';
} else {
return c;
}
}
int getCursorPosition(int *rows, int *cols) {
char buf[32];
unsigned int i = 0;
if (write(STDOUT_FILENO, "\x1b[6n", 4) != 4)
return -1;
while (i < sizeof(buf) - 1) {
if (read(STDIN_FILENO, &buf[i], 1) != 1)
break;
if (buf[i] == 'R')
break;
i++;
}
buf[i] = '\0';
if (buf[0] != '\x1b' || buf[1] != '[')
return -1;
if (sscanf(&buf[2], "%d;%d", rows, cols) != 2)
return -1;
return 0;
}
int getWindowSize(int *rows, int *cols) {
struct winsize ws;
if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 || ws.ws_col == 0) {
if (write(STDOUT_FILENO, "\x1b[999C\x1b[999B", 12) != 12)
return -1; // fallback
return getCursorPosition(rows, cols);
} else {
*cols = ws.ws_col;
*rows = ws.ws_row;
return 0;
}
}
/*** append buffer ***/
struct abuf {
char *b;
int len;
};
#define ABUF_INIT \
{ NULL, 0 }
void abAppend(struct abuf *ab, const char *s, int len) {
char *new = realloc(ab->b, ab->len + len);
if (new == NULL)
return;
memcpy(&new[ab->len], s, len);
ab->b = new;
ab->len += len;
}
void abFree(struct abuf *ab) { free(ab->b); }
/*** output ***/
void editorDrawRows(struct abuf *ab) {
int y;
for (y = 0; y < E.screenrows; y++) {
if (y == E.screenrows / 3) {
char welcome[80];
int welcomelen = snprintf(welcome, sizeof(welcome),
"Kilo editor -- version %s", KILO_VERSION);
if (welcomelen > E.screencols)
welcomelen = E.screencols;
int padding = (E.screencols - welcomelen) / 2;
if (padding) {
abAppend(ab, "~", 1);
padding--;
}
while (padding--)
abAppend(ab, " ", 1);
abAppend(ab, welcome, welcomelen);
} else {
abAppend(ab, "~", 1);
}
abAppend(ab, "\x1b[K", 3);
if (y < E.screenrows - 1) {
abAppend(ab, "\r\n", 2);
}
}
}
void editorRefreshScreen() {
struct abuf ab = ABUF_INIT;
abAppend(&ab, "\x1b[?25l", 6);
abAppend(&ab, "\x1b[H", 3);
editorDrawRows(&ab);
char buf[32];
snprintf(buf, sizeof(buf), "\x1b[%d;%dH", E.cy + 1, E.cx + 1);
abAppend(&ab, buf, strlen(buf));
abAppend(&ab, "\x1b[?25h", 6);
write(STDOUT_FILENO, ab.b, ab.len);
abFree(&ab);
}
/*** input ***/
void editorMoveCursor(int key) {
switch (key) {
case ARROW_LEFT:
if (E.cx != 0) {
E.cx--;
}
break;
case ARROW_RIGHT:
if (E.cx != E.screencols - 1) {
E.cx++;
}
break;
case ARROW_UP:
if (E.cy != 0) {
E.cy--;
}
break;
case ARROW_DOWN:
if (E.cy != E.screenrows - 1) {
E.cy++;
}
break;
}
}
void editorProcessKeypress() {
int c = editorReadKey();
switch (c) {
case CTRL_KEY('q'):
write(STDOUT_FILENO, "\x1b[2J", 4);
write(STDOUT_FILENO, "\x1b[H", 3);
exit(0);
break;
case HOME_KEY:
E.cx = 0;
break;
case END_KEY:
E.cx = E.screencols - 1;
break;
case PAGE_UP:
case PAGE_DOWN: {
int times = E.screenrows;
while (times--)
editorMoveCursor(c == PAGE_UP ? ARROW_UP : ARROW_DOWN);
} break;
case ARROW_UP:
case ARROW_DOWN:
case ARROW_LEFT:
case ARROW_RIGHT:
editorMoveCursor(c);
break;
}
}
/*** init ***/
void initEditor() {
E.cx = 0;
E.cy = 0;
if (getWindowSize(&E.screenrows, &E.screencols) == -1)
die("getWindowSize");
}
int main() {
enableRawMode();
initEditor();
while (1) {
editorRefreshScreen();
editorProcessKeypress();
}
return 0;
}