651 lines
10 KiB
C
651 lines
10 KiB
C
/*
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* kyle's editor
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*
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* first version is a run-through of the kilo editor walkthrough.
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* https://viewsourcecode.org/snaptoken/kilo/
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*/
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#include <sys/ioctl.h>
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#include <ctype.h>
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#include <errno.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 <termios.h>
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#include <unistd.h>
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#define KE_VERSION "0.0.1-pre"
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#define ESCSEQ "\x1b["
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#define CTRL_KEY(key) ((key)&0x1f)
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#define TAB_STOP 8
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/*
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* define the keyboard input modes
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* normal: no special mode
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* kcommand: ^k commands
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*/
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#define MODE_NORMAL 0
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#define MODE_KCOMMAND 1
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#define MODE_INSERT 2
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enum KeyPress {
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ARROW_UP = 1000,
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ARROW_DOWN,
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ARROW_LEFT,
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ARROW_RIGHT,
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DEL_KEY,
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END_KEY,
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HOME_KEY,
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PG_UP,
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PG_DN,
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};
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void disable_termraw();
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typedef struct erow {
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char *line;
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char *render;
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int size;
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int rsize;
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} erow;
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struct {
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struct termios entry_term;
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int rows, cols;
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int curx, cury;
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int rx;
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int mode;
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int nrows;
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int rowoffs, coloffs;
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erow *row;
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} editor;
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/* append buffer */
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struct abuf {
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char *b;
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int len;
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};
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#define ABUF_INIT {NULL, 0}
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void
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ab_append(struct abuf *buf, const char *s, int len)
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{
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char *nc = realloc(buf->b, buf->len + len);
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if (nc == NULL) {
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return;
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}
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memcpy(&nc[buf->len], s, len);
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buf->b = nc;
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buf->len += len; /* DANGER: overflow */
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}
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void
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ab_free(struct abuf *buf)
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{
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free(buf->b);
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}
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void
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die(const char *s)
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{
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/*
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* NOTE(kyle): this is a duplication of the code in display.c
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* but I would like to be able to import these files from there.
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*/
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write(STDOUT_FILENO, "\x1b[2J", 4);
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write(STDOUT_FILENO, "\x1b[H", 3);
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perror(s);
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exit(1);
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}
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/*
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* get_winsz uses the TIOCGWINSZ to get the window size.
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*
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* there's a fallback way to do this, too, that involves moving the
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* cursor down and to the left \x1b[999C\x1b[999B. I'm going to skip
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* on this for now because it's bloaty and this works on OpenBSD and
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* Linux, at least.
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*/
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int
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get_winsz(int *rows, int *cols)
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{
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struct winsize ws;
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if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 ||
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ws.ws_col == 0) {
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return -1;
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}
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*cols = ws.ws_col;
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*rows = ws.ws_row;
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return 0;
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}
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void
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update_row(erow *row)
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{
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int i = 0, j;
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int tabs = 0;
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/*
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* TODO(kyle): I'm not thrilled with this double-render.
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*/
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for (j = 0; j < row->size; j++) {
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if (row->line[j] == '\t') {
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tabs++;
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}
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}
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free(row->render);
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row->render = malloc(row->size + (tabs * (TAB_STOP-1)) + 1);
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for (j = 0; j < row->size; j++) {
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if (row->line[j] == '\t') {
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do {
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row->render[i++] = ' ';
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} while ((i % TAB_STOP) != 0);
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} else {
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row->render[i++] = row->line[j];
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}
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}
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row->render[i] = '\0';
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row->rsize = i;
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}
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void
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append_row(char *s, size_t len)
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{
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int at = editor.nrows;
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editor.row = realloc(editor.row, sizeof(erow) * (editor.nrows + 1));
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editor.row[at].size = len;
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editor.row[at].line = malloc(len+1);
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memcpy(editor.row[at].line, s, len);
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editor.row[at].line[len] = '\0';
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editor.row[at].rsize = 0;
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editor.row[at].render = NULL;
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update_row(&editor.row[at]);
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editor.nrows++;
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}
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void
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open_file(const char *filename)
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{
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char *line = NULL;
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size_t linecap = 0;
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ssize_t linelen;
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FILE *fp = fopen(filename, "r");
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if (!fp) {
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die("fopen");
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}
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while ((linelen = getline(&line, &linecap, fp)) != -1) {
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if (linelen != -1) {
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while ((linelen > 0) && ((line[linelen-1] == '\r') ||
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(line[linelen-1] == '\n'))) {
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linelen--;
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}
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append_row(line, linelen);
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}
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}
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free(line);
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fclose(fp);
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}
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uint16_t
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is_arrow_key(int16_t c)
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{
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switch (c) {
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case ARROW_UP:
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case ARROW_DOWN:
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case ARROW_LEFT:
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case ARROW_RIGHT:
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case CTRL_KEY('p'):
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case CTRL_KEY('n'):
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case CTRL_KEY('f'):
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case CTRL_KEY('b'):
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case PG_UP:
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case PG_DN:
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case HOME_KEY:
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case END_KEY:
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return 1;
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};
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return 0;
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}
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int16_t
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get_keypress()
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{
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char seq[3];
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char c = -1;
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if (read(STDIN_FILENO, &c, 1) == -1) {
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die("get_keypress:read");
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}
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if (c == 0x1b) {
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if (read(STDIN_FILENO, &seq[0], 1) != 1) return c;
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if (read(STDIN_FILENO, &seq[1], 1) != 1) return c;
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if (seq[0] == '[') {
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if (seq[1] < 'A') {
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if (read(STDIN_FILENO, &seq[2], 1) != 1)
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return c;
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if (seq[2] == '~') {
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switch (seq[1]) {
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case '1': return HOME_KEY;
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case '2': return END_KEY;
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case '3': return DEL_KEY;
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case '5': return PG_UP;
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case '6': return PG_DN;
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case '7': return HOME_KEY;
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case '8': return END_KEY;
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}
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}
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} else {
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switch (seq[1]) {
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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 'F': return END_KEY;
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case 'H': return HOME_KEY;
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default:
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/* nada */ ;
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}
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}
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} else if (seq[0] == 'O') {
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switch (seq[1]) {
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case 'F': return END_KEY;
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case 'H': return HOME_KEY;
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}
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}
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return 0x1b;
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}
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return c;
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}
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void
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move_cursor(int16_t c)
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{
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erow *row = (editor.cury >= editor.nrows) ?
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NULL : &editor.row[editor.cury];
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int reps;
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switch (c) {
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case ARROW_UP:
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case CTRL_KEY('p'):
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if (editor.cury > 0) {
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editor.cury--;
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}
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break;
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case ARROW_DOWN:
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case CTRL_KEY('n'):
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if (editor.cury < editor.nrows) {
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editor.cury++;
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}
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break;
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case ARROW_RIGHT:
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case CTRL_KEY('f'):
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if (row && editor.curx < row->size) {
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editor.curx++;
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} else if (row && editor.curx == row->size) {
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editor.cury++;
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editor.curx = 0;
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}
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break;
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case ARROW_LEFT:
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case CTRL_KEY('b'):
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if (editor.curx > 0) {
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editor.curx--;
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} else if (editor.cury > 0) {
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editor.cury--;
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editor.curx = editor.row[editor.cury].size;
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}
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break;
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case PG_UP:
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case PG_DN: {
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if (c == PG_UP) {
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editor.cury = editor.rowoffs;
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} else if (c == PG_DN) {
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editor.cury = editor.rowoffs + editor.rows-1;
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if (editor.cury > editor.nrows) {
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editor.cury = editor.nrows;
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}
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}
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reps = editor.rows;
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while (--reps) {
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move_cursor(c == PG_UP ? ARROW_UP : ARROW_DOWN);
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}
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}
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case HOME_KEY:
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editor.curx = 0;
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break;
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case END_KEY:
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editor.curx = editor.cols - 1;
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break;
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default:
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break;
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}
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row = (editor.cury >= editor.nrows) ?
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NULL : &editor.row[editor.cury];
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reps = row ? row->size : 0;
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if (editor.curx > reps) {
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editor.curx = reps;
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}
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}
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void
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process_kcommand(int16_t c)
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{
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switch (c) {
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case 'q':
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case CTRL_KEY('q'):
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exit(0);
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case 'd':
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case CTRL_KEY('\\'):
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/* sometimes it's nice to dump core */
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disable_termraw();
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abort();
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}
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editor.mode = MODE_NORMAL;
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return;
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}
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void
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process_keypress()
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{
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int16_t c = get_keypress();
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/* we didn't actually read a key */
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if (c <= 0) {
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return;
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}
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switch (editor.mode) {
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case MODE_KCOMMAND:
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process_kcommand(c);
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break;
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case MODE_NORMAL:
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if (is_arrow_key(c)) {
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move_cursor(c);
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}
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}
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if (c == CTRL_KEY('k')) {
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editor.mode = MODE_KCOMMAND;
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return;
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}
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}
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/*
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* A text editor needs the terminal to be in raw mode; but the default
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* is to be in canonical (cooked) mode, which is a buffered input mode.
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*/
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static void
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enable_termraw()
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{
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struct termios raw;
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/* Read the current terminal parameters for standard input. */
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if (tcgetattr(STDIN_FILENO, &raw) == -1) {
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die("tcgetattr while enabling raw mode");
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}
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/*
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* Put the terminal into raw mode.
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*/
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cfmakeraw(&raw);
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/*
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* Set timeout for read(2).
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*
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* VMIN: what is the minimum number of bytes required for read
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* to return?
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*
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* VTIME: max time before read(2) returns in hundreds of milli-
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* seconds.
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*/
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raw.c_cc[VMIN] = 0;
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raw.c_cc[VTIME] = 1;
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/*
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* Now write the terminal parameters to the current terminal,
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* after flushing any waiting input out.
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*/
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if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1) {
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die("tcsetattr while enabling raw mode");
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}
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}
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void
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display_clear(struct abuf *ab)
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{
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if (ab == NULL) {
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write(STDOUT_FILENO, ESCSEQ "2J", 4);
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write(STDOUT_FILENO, ESCSEQ "H", 3);
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} else {
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ab_append(ab, ESCSEQ "2J", 4);
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ab_append(ab, ESCSEQ "H", 3);
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}
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}
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void
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disable_termraw()
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{
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display_clear(NULL);
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if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &editor.entry_term) == -1) {
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die("couldn't disable terminal raw mode");
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}
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}
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void
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setup_terminal()
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{
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if (tcgetattr(STDIN_FILENO, &editor.entry_term) == -1) {
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die("can't snapshot terminal settings");
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}
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atexit(disable_termraw);
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enable_termraw();
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}
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void
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draw_rows(struct abuf *ab)
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{
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char buf[editor.cols];
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int buflen, filerow, padding;
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int y;
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for (y = 0; y < editor.rows; y++) {
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filerow = y + editor.rowoffs;
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if (filerow >= editor.nrows) {
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if ((editor.nrows == 0) && (y == editor.rows / 3)) {
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buflen = snprintf(buf, sizeof(buf),
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"ke k%s", KE_VERSION);
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padding = (editor.rows - buflen) / 2;
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if (padding) {
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ab_append(ab, "|", 1);
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padding--;
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}
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while (padding--) ab_append(ab, " ", 1);
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ab_append(ab, buf, buflen);
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} else {
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ab_append(ab, "|", 1);
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}
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} else {
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buflen = editor.row[filerow].rsize - editor.coloffs;
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if (buflen < 0) {
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buflen = 0;
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}
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if (buflen > editor.cols) {
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buflen = editor.cols;
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}
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ab_append(ab, editor.row[filerow].render+editor.coloffs,
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buflen);
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}
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ab_append(ab, ESCSEQ "K", 3);
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if (y < (editor.rows - 1)) {
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ab_append(ab, "\r\n", 2);
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}
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}
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}
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int
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row_render_to_cursor(erow *row, int cx)
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{
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int rx = 0;
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int j;
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for (j = 0; j < cx; j++) {
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if (row->line[j] == '\t') {
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rx += (TAB_STOP-1) - (rx%TAB_STOP);
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}
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rx++;
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}
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return rx;
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}
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void
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scroll()
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{
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editor.rx = 0;
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if (editor.cury < editor.nrows) {
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editor.rx = row_render_to_cursor(
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&editor.row[editor.cury],
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editor.curx);
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}
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if (editor.cury < editor.rowoffs) {
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editor.rowoffs = editor.cury;
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}
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if (editor.cury >= editor.rowoffs + editor.rows) {
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editor.rowoffs = editor.cury - editor.rows + 1;
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}
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if (editor.rx < editor.coloffs) {
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editor.coloffs = editor.rx;
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}
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if (editor.rx >= editor.coloffs + editor.cols) {
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editor.coloffs = editor.rx - editor.cols + 1;
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}
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}
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void
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display_refresh()
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{
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char buf[32];
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struct abuf ab = ABUF_INIT;
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scroll();
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ab_append(&ab, ESCSEQ "?25l", 6);
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display_clear(&ab);
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draw_rows(&ab);
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snprintf(buf, sizeof(buf), ESCSEQ "%d;%dH",
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(editor.cury-editor.rowoffs)+1,
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(editor.rx-editor.coloffs)+1);
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ab_append(&ab, buf, strnlen(buf, 32));
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/* ab_append(&ab, ESCSEQ "1;2H", 7); */
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ab_append(&ab, ESCSEQ "?25h", 6);
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write(STDOUT_FILENO, ab.b, ab.len);
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ab_free(&ab);
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}
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void
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loop()
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{
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while (1) {
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display_refresh();
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process_keypress();
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}
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|
}
|
|
|
|
|
|
/*
|
|
* init_editor should set up the global editor struct.
|
|
*/
|
|
void
|
|
init_editor()
|
|
{
|
|
if (get_winsz(&editor.rows, &editor.cols) == -1) {
|
|
die("can't get window size");
|
|
}
|
|
|
|
editor.curx = editor.cury = 0;
|
|
editor.rx = 0;
|
|
|
|
editor.nrows = 0;
|
|
editor.rowoffs = editor.coloffs = 0;
|
|
editor.row = NULL;
|
|
}
|
|
|
|
|
|
int
|
|
main(int argc, char *argv[])
|
|
{
|
|
setup_terminal();
|
|
init_editor();
|
|
|
|
if (argc > 1) {
|
|
open_file(argv[1]);
|
|
}
|
|
|
|
display_clear(NULL);
|
|
loop();
|
|
|
|
return 0;
|
|
}
|