365 lines
8 KiB
C
365 lines
8 KiB
C
#include <ctype.h>
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#include <errno.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <termios.h>
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#include <unistd.h>
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#define CTRL_KEY(key) ((key) & 0x1f)
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/*****************************************************************************/
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struct {
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struct termios orig_termios;
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int rows;
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int cols;
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int cx, cy;
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struct input_buf *ib;
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} E;
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enum keys {
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HOME = 0x100 + 1,
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DEL,
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PG_UP,
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PG_DOWN,
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END,
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ARROW_UP,
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ARROW_DOWN,
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ARROW_LEFT,
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ARROW_RIGHT,
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NOP
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};
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struct screen_buf;
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struct input_buf;
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/*****************************************************************************/
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void editor_init();
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void editor_redraw_screen();
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void editor_draw_rows(struct screen_buf *);
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void editor_process_key();
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int editor_read_key();
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int term_enable_raw();
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void term_disable_raw();
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int term_clear();
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int term_cursor_hidden(bool);
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int term_get_win_size(int *, int *);
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int term_get_cursor_pos(int *, int *);
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int term_set_cursor_pos(int, int);
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struct screen_buf *sb_init();
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void sb_append(struct screen_buf *, const char *);
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void sb_free(struct screen_buf *);
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void sb_write(struct screen_buf *);
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struct input_buf *ib_init(size_t);
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int ib_read(struct input_buf *);
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void ib_write(struct input_buf *, int);
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bool ib_empty(struct input_buf *);
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void ib_free(struct input_buf *);
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void die(const char *);
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/*****************************************************************************/
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int main() {
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editor_init();
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while (1) {
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editor_redraw_screen();
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editor_process_key();
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}
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return 0;
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}
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/*****************************************************************************/
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void editor_init() {
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if (!isatty(STDIN_FILENO)) {
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printf("kilo only supports a terminal at standard in. Exiting.");
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exit(1);
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}
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if (term_enable_raw() == -1) die("term_enable_raw");
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if (term_get_win_size(&E.rows, &E.cols) == -1) die("term_get_win_size");
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E.cx = E.cy = 0;
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E.ib = ib_init(128);
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}
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void editor_redraw_screen() {
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if (term_cursor_hidden(true) == -1) die("term_cursor_hidden");
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struct screen_buf *sb = sb_init();
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editor_draw_rows(sb);
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sb_write(sb);
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sb_free(sb);
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if (term_set_cursor_pos(E.cy + 1, E.cx + 1) == -1) die("term_set_cursor_pos");
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if (term_cursor_hidden(false) == -1) die("term_cursor_hidden");
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}
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void editor_draw_rows(struct screen_buf *sb) {
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term_set_cursor_pos(1, 1);
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for (int y = 0; y < E.rows; y++) {
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sb_append(sb, "~");
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sb_append(sb, "\x1b[K"); // Clear rest of the line
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if (y < E.rows - 1) sb_append(sb, "\r\n");
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}
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}
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void editor_process_key() {
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int c = editor_read_key();
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switch (c) {
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case CTRL_KEY('Q'):
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term_clear();
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exit(0);
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break;
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case ARROW_LEFT:
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if (E.cx > 0) E.cx--;
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break;
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case ARROW_DOWN:
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if (E.cy < E.rows - 1) E.cy++;
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break;
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case ARROW_UP:
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if (E.cy > 0) E.cy--;
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break;
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case ARROW_RIGHT:
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if (E.cx < E.cols - 1) E.cx++;
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break;
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}
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}
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int editor_read_key() {
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// TODO: There's better ways to do this.
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// Somehow make everything go through the input buffer
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if (!ib_empty(E.ib))
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return ib_read(E.ib);
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char c;
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while (read(STDIN_FILENO, &c, 1) == 0);
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if (c == '\x1b') {
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char buf[8];
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for (size_t i = 0; i < sizeof(buf); i++) {
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if (read(STDIN_FILENO, buf+i, 1) == 0) {
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buf[i] = '\0';
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break;
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}
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}
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char escape_char;
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if (sscanf(buf, "[%c~", &escape_char) != EOF) {
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switch (escape_char) {
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case 'A': return ARROW_UP;
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case 'B': return ARROW_DOWN;
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case 'C': return ARROW_RIGHT;
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case 'D': return ARROW_LEFT;
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case 'H': return HOME;
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case 'F': return END;
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}
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}
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int escape_int;
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if (sscanf(buf, "[%d~", &escape_int) != EOF) {
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switch (escape_int) {
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case 1:
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case 7:
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return HOME;
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case 3:
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return DEL;
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case 4:
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case 8:
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return END;
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case 5:
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return PG_UP;
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case 6:
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return PG_DOWN;
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}
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}
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return NOP;
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}
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return (int) c;
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}
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/*****************************************************************************/
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int term_enable_raw() {
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if (tcgetattr(STDIN_FILENO, &E.orig_termios) == -1) return -1;
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atexit(term_disable_raw);
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struct termios raw = E.orig_termios;
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cfmakeraw(&raw);
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raw.c_cc[VMIN] = 0;
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raw.c_cc[VTIME] = 1;
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if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1) return -1;
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return 0;
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}
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void term_disable_raw() {
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if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == -1)
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die ("term_disable_raw");
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}
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int term_clear() {
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if (write(STDOUT_FILENO, "\x1b[2J", 4) != 4) return -1;
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if (write(STDOUT_FILENO, "\x1b[H", 3) != 3) return -1;
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return 0;
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}
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int term_cursor_hidden(bool hidden) {
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if (write(STDOUT_FILENO, (hidden ? "\x1b[?25l" : "\x1b[?25h"), 6) != 6)
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return -1;
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return 0;
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}
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int term_get_win_size(int *row, int *col) {
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struct winsize ws;
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if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) != -1 && ws.ws_col != 0) {
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*row = ws.ws_row;
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*col = ws.ws_col;
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return 0;
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} else {
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if (write(STDOUT_FILENO, "\x1b[999C\x1b[999B", 12) != 12) return -1;
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return term_get_cursor_pos(row, col);
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}
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}
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int term_get_cursor_pos(int *row, int *col) {
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char buf[32];
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if (write(STDOUT_FILENO, "\x1b[6n", 4) != 4) return -1;
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for (size_t i = 0; i < sizeof(buf); i++) {
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if (read(STDIN_FILENO, buf+i, 1) == 0 || buf[i] == 'R') {
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buf[i] = '\0';
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break;
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}
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}
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if (sscanf(buf, "\x1b[%d;%d", row, col) == EOF)
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return -1;
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return 0;
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}
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int term_set_cursor_pos(int row, int col) {
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char buf[16];
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size_t len = snprintf(buf, sizeof(buf), "\x1b[%d;%dH", row, col);
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len = (len >= sizeof(buf) ? sizeof(buf) - 1 : len);
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if (write(STDOUT_FILENO, buf, len) != (ssize_t) len) return -1;
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return 0;
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}
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/*****************************************************************************/
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struct screen_buf {
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char *s;
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size_t size;
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};
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struct screen_buf *sb_init() {
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struct screen_buf *sb = (struct screen_buf *) malloc(sizeof(struct screen_buf));
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sb->s = NULL;
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sb->size = 0;
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return sb;
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}
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void sb_append(struct screen_buf *sb, const char *s) {
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int size = strlen(s);
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sb->s = realloc(sb->s, sb->size + size);
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memcpy(sb->s + sb->size, s, size);
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sb->size += size;
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}
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void sb_write(struct screen_buf *sb) {
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write(STDOUT_FILENO, sb->s, sb->size);
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}
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void sb_free(struct screen_buf *sb) {
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free(sb->s);
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free(sb);
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}
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struct input_buf {
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int *carr; // Circular array
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int read_i;
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int write_i;
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size_t capacity; // Actual capacity is one less
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};
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struct input_buf *ib_init(size_t capacity) {
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struct input_buf *ib = (struct input_buf *) malloc(sizeof(struct input_buf));
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ib->carr = (int *) malloc(sizeof(int) * capacity);
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ib->write_i = 0;
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ib->read_i = 0;
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ib->capacity = capacity;
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return ib;
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}
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void ib_write(struct input_buf *ib, int key) {
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if ((ib->write_i + 1) % (int) ib->capacity == ib->read_i) // Buffer full
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die("ib_write");
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ib->carr[ib->write_i] = key;
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ib->write_i = (ib->write_i + 1) % ib->capacity;
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}
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int ib_read(struct input_buf *ib) {
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if (ib_empty(ib)) die("ib_read");
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int key = ib->carr[ib->read_i];
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ib->read_i = (ib->read_i + 1) % ib->capacity;
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return key;
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}
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bool ib_empty(struct input_buf *ib) {
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return ib->write_i == ib->read_i;
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}
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void ib_free(struct input_buf *ib) {
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free(ib->carr);
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free(ib);
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}
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/*****************************************************************************/
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void die(const char *s) {
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term_clear();
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perror(s);
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exit(1);
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}
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