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level-editor/level.cpp
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SowinskiBraeden f543de9135 debug last commit
2022-09-06 21:24:21 -07:00

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/*** includes ***/
#define _DEFAULT_SOURCE
#define _BSD_SOURCE
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif //_GNU_SOURCE
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <termios.h>
#include <time.h>
#include <unistd.h>
/*** defines ***/
#define LEVEL_VERSION "0.0.1"
#define LEVEL_TAB_STOP 8
#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 ***/
// erow stands for "editor row"
typedef struct erow {
int size;
int rsize;
char *chars;
char *render;
} erow;
struct editorConfig {
int cx, cy;
int rx;
int rowoff;
int coloff;
int screenrows;
int screencols;
int numrows;
erow *row;
char *filename;
char statusmsg[80];
time_t statusmsg_time;
struct termios orig_termios;
};
struct editorConfig E;
/*** terminal ***/
void die(const char *s) {
// Clear the screen before we show error
write(STDOUT_FILENO, "\x1b[2J", 4);
write(STDOUT_FILENO, "\x1b[H", 3);
perror(s);
exit(1);
}
// This function restores the terminals original attributes on program exit.
void disableRawMode() {
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == -1)
die("tcsetattr");
}
/*
This function disables echo for better rendering in raw mode as
well as disbaling Canonical mode. This enables the program to read
input byte-by-byte instead of line-by-line. We also disable several
Ctrl functions as they terminate, suspend, or generally affect
the process.
*/
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] == '0') {
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;
return getCursorPosition(rows, cols);
} else {
*cols = ws.ws_col;
*rows = ws.ws_row;
return 0;
}
}
/*** row operations ***/
int editorRowCxToRx(erow *row, int cx) {
int rx = 0;
for (int j = 0; j < cx; j++) {
if (row->chars[j] == '\t') rx += (LEVEL_TAB_STOP - 1) - (rx % LEVEL_TAB_STOP);
rx++;
}
return rx;
}
void editorUpdateRow(erow *row) {
int tabs = 0;
for (int j = 0; j < row->size; j++) {
if (row->chars[j] == '\t') tabs++;
}
free(row->render);
row->render = (char*)malloc(row->size + tabs*(LEVEL_TAB_STOP - 1) + 1);
int idx = 0;
for (int j = 0; j < row->size; j++) {
if (row->chars[j] == '\t') {
row->render[idx++] = ' ';
while (idx % LEVEL_TAB_STOP != 0) row->render[idx++] = ' ';
} else {
row->render[idx++] = row->chars[j];
}
}
row->render[idx] = '\0';
row->rsize = idx;
}
void editorAppendRow(char *s, size_t len) {
E.row = (erow*)realloc(E.row, sizeof(erow) * (E.numrows + 1));
int at = E.numrows;
E.row[at].size = len;
E.row[at].chars = (char*)malloc(len + 1);
memcpy(E.row[at].chars, s, len);
E.row[at].chars[len] = '\0';
E.row[at].rsize = 0;
E.row[at].render = NULL;
editorUpdateRow(&E.row[at]);
E.numrows++;
}
/*** file i/o ***/
void editorOpen(char *filename) {
free(E.filename);
E.filename = strdup(filename);
FILE *fp = fopen(filename, "r");
if (!fp) die("fopen");
char *line = NULL;
size_t linecap = 0;
ssize_t linelen;
while ((linelen = getline(&line, &linecap, fp)) != -1) {
while (linelen > 0 && (line[linelen - 1] == '\n' ||
line[linelen - 1] == '\r'))
linelen--;
editorAppendRow(line, linelen);
}
free(line);
fclose(fp);
}
/*** append buffer ***/
struct abuf {
char *b;
int len;
};
#define ABUF_INIT {NULL, 0}
void abAppend(struct abuf *ab, const char *s, int len) {
char *newAB = (char*)realloc(ab->b, ab->len + len);
if (newAB == NULL) return;
memcpy(&newAB[ab->len], s, len);
ab->b = newAB;
ab->len += len;
}
void abFree(struct abuf *ab) {
free(ab->b);
}
/*** output ***/
void editorScroll() {
E.rx = 0;
if (E.cy < E.numrows) E.rx = editorRowCxToRx(&E.row[E.cy], E.cx);
if (E.cy < E.rowoff) E.rowoff = E.cy;
if (E.cy >= E.rowoff + E.screenrows) E.rowoff = E.cy - E.screenrows + 1;
if (E.cx < E.coloff) E.coloff = E.rx;
if (E.cx >= E.coloff + E.screencols) E.coloff = E.rx - E.screencols + 1;
}
void editorDrawRows(struct abuf *ab) {
for (int y = 0; y < E.screenrows; y++) {
int filerow = y + E.rowoff;
if (filerow >= E.numrows) {
if (E.numrows == 0 && y == E.screenrows / 3) {
char welcome[80];
int welcomelen = snprintf(welcome, sizeof(welcome),
"Level editor -- version %s", LEVEL_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);
}
} else {
int len = E.row[filerow].rsize - E.coloff;
if (len < 0) len = 0;
if (len > E.screencols) len = E.screencols;
abAppend(ab, &E.row[filerow].render[E.coloff], len);
}
abAppend(ab, "\x1b[K", 3);
abAppend(ab, "\r\n", 2);
}
}
void editorDrawStatusBar(struct abuf* ab) {
abAppend(ab, "\x1b[7m", 4);
char status[80], rstatus[80];
int len = snprintf(status, sizeof(status), "%.20s - %d lines",
E.filename ? E.filename : "[No Name]", E.numrows);
int rlen = snprintf(rstatus, sizeof(rstatus), "%d/%d",
E.cy + 1, E.numrows);
if (len > E.screencols) len = E.screencols;
abAppend(ab, status, len);
while (len < E.screencols) {
if (E.screencols - len == rlen) {
abAppend(ab, rstatus, rlen);
break;
} else {
abAppend(ab, " ", 1);
len++;
}
}
abAppend(ab, "\x1b[m", 3);
abAppend(ab, "\r\n", 2);
}
void editorDrawMessageBar(struct abuf* ab) {
abAppend(ab, "\x1b[K", 3);
int msglen = strlen(E.statusmsg);
if (msglen > E.screencols) msglen = E.screencols;
if (msglen && time(NULL) - E.statusmsg_time < 5) abAppend(ab, E.statusmsg, msglen);
}
void editorRefreshScreen() {
editorScroll();
struct abuf ab = ABUF_INIT;
abAppend(&ab, "\x1b[?25l", 6);
abAppend(&ab, "\x1b[H", 3);
editorDrawRows(&ab);
editorDrawStatusBar(&ab);
editorDrawMessageBar(&ab);
char buf[32];
snprintf(buf, sizeof(buf), "\x1b[%d;%dH", (E.cy - E.rowoff) + 1,
(E.rx - E.coloff) + 1);
abAppend(&ab, buf, strlen(buf));
abAppend(&ab, "\x1b[?25h", 6);
write(STDOUT_FILENO, ab.b, ab.len);
abFree(&ab);
}
void editorSetStatusMessage(const char* fmt, ...) {
va_list ap;
va_start(ap, fmt);
vsnprintf(E.statusmsg, sizeof(E.statusmsg), fmt, ap);
va_end(ap);
E.statusmsg_time = time(NULL);
}
/*** input ***/
void editorMoveCursor(int key) {
erow* row = (E.cy >= E.numrows) ? NULL : &E.row[E.cy];
switch (key) {
case ARROW_LEFT:
if (E.cx != 0) E.cx--;
break;
case ARROW_RIGHT:
if (row && E.cx < row->size) E.cx++;
break;
case ARROW_UP:
if (E.cy != 0) E.cy--;
break;
case ARROW_DOWN:
if (E.cy < E.numrows - 1) E.cy++;
break;
}
row = (E.cy >= E.numrows) ? NULL : &E.row[E.cy];
int rowlen = row ? row->size : 0;
if (E.cx > rowlen) E.cx = rowlen;
}
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:
if (E.cy < E.numrows) E.cx = E.row[E.cy].size;
break;
case PAGE_UP:
case PAGE_DOWN:
{
if (c == PAGE_UP) E.cy = E.rowoff;
else if (c == PAGE_DOWN) {
E.cy = E.rowoff + E.screenrows - 1;
if (E.cy > E.numrows) E.cy = E.numrows;
}
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;
E.rx = 0;
E.rowoff = 0;
E.coloff = 0;
E.numrows = 0;
E.row = NULL;
E.filename = NULL;
E.statusmsg[0] = '\0';
E.statusmsg_time = 0;
if (getWindowSize(&E.screenrows, &E.screencols) == -1) die("getWindowSize");
E.screenrows -= 2;
}
int main(int argc, char *argv[]) {
enableRawMode();
initEditor();
if (argc >= 2) editorOpen(argv[1]);
editorSetStatusMessage("HELP: Ctrl-Q = quit");
while (1) {
editorRefreshScreen();
editorProcessKeypress();
}
return 0;
}
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