tted/kilo.c
2021-10-20 23:13:21 -04:00

171 lines
4.1 KiB
C

/*** 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)
/*** data ***/
struct editorConfig {
int screenrows;
int screencols;
struct termios orig_termios;
};
struct editorConfig E;
/*** terminal ***/
void die(const char *s){
write(STDOUT_FILENO, "\x1b[2J", 4);
write(STDOUT_FILENO, "\x1b[H", 3);
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");
}
char editorReadKey() {
int nread;
char c;
while ((nread = read(STDIN_FILENO, &c, 1)) != 1){
if (nread == -1 && errno != EAGAIN) die("read");
}
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'; //assign null to final byte
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;
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);
int padding = (E.screencols - welcomelen) /2;
if(padding) {
abAppend(ab, "~", 1);
padding--;
}
while(padding--) abAppend(ab, " ", 1);
if (welcomelen > E.screencols) welcomelen = E.screencols;
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); // Cursor Position home
editorDrawRows(&ab);
abAppend(&ab, "\x1b[H",3); // Cursor Position home
abAppend(&ab, "\x1b[?25h", 6);
write(STDOUT_FILENO, ab.b, ab.len);
abFree(&ab);
}
/*** input ***/
void editorProcessKeypress() {
char c = editorReadKey();
switch (c) {
case CTRL_KEY('q'):
write(STDOUT_FILENO, "\x1b[2J", 4);
write(STDOUT_FILENO, "\x1b[H", 3);
exit(0);
break;
}
}
/*** init ***/
void initEditor() {
if (getWindowSize(&E.screenrows, &E.screencols) == -1) die("getWindowSize");
}
int main() {
enableRawMode();
initEditor();
while(1) {
editorRefreshScreen();
editorProcessKeypress();
}
return 0;
}