commit bef8fd90772fcd0db1f260e5120224bbedbd656c Author: Braeden Sowinski Date: Tue Sep 6 17:46:44 2022 -0700 first commit diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..59c8aa1 --- /dev/null +++ b/.gitignore @@ -0,0 +1,5 @@ +# Visual Studio Config +.vs/* + +# Output +level \ No newline at end of file diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..3b08c60 --- /dev/null +++ b/Makefile @@ -0,0 +1,2 @@ +level: level.cpp + $(CC) level.cpp -o level -Wall -Wextra -pedantic diff --git a/level.cpp b/level.cpp new file mode 100644 index 0000000..cd03e35 --- /dev/null +++ b/level.cpp @@ -0,0 +1,303 @@ +/*** includes ***/ + +#include +#include +#include +#include +#include +#include +#include +#include + +/*** defines ***/ + +#define LEVEL_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) { + // 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; + } +} + +/*** 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 editorDrawRows(struct abuf *ab) { + for (int y = 0; y < E.screenrows; y++) { + if (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); + } + + 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[2J", 4); This line clears whole screen + 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; +}