Make terminal ui binaries work well everywhere

Here's some screenshots of an emulator tui program that was compiled on Linux, then scp'd it to Windows, Mac, and FreeBSD. https://justine.storage.googleapis.com/blinkenlights-cmdexe.png https://justine.storage.googleapis.com/blinkenlights-imac.png https://justine.storage.googleapis.com/blinkenlights-freebsd.png https://justine.storage.googleapis.com/blinkenlights-lisp.png How is this even possible that we have a nontrivial ui binary that just works on Mac, Windows, Linux, and BSD? Surely a first ever achievement. Fixed many bugs. Bootstrapped John McCarthy's metacircular evaluator on bare metal in half the size of Altair BASIC (about 2.5kb) and ran it in emulator for fun and profit.
2025-07-05 18:58:30 +00:00 · 2020-10-10 21:18:53 -07:00 · 2020-10-10 21:18:53 -07:00 · 9e3e985ae5
commit 9e3e985ae5
parent 680daf1210
276 changed files with 7026 additions and 3790 deletions
--- a/libc/calls/readansi.c
+++ b/libc/calls/readansi.c
@ -0,0 +1,124 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/str/thompike.h"
+#include "libc/sysv/errfuns.h"
+
+/**
+ * Reads single keystroke or control sequence from character device.
+ *
+ * When reading ANSI UTF-8 text streams, characters and control codes
+ * are oftentimes encoded as multi-byte sequences. This function knows
+ * how long each sequence is, so that each read consumes a single thing
+ * from the underlying file descriptor, e.g.
+ *
+ *   "a"               ALFA
+ *   "\316\261"        ALPHA
+ *   "\033[A"          CURSOR UP
+ *   "\033[38;5;202m"  ORANGERED
+ *   "\eOP"            PF1
+ *
+ * This routine generalizes to ascii, utf-8, chorded modifier keys,
+ * function keys, color codes, c0/c1 control codes, cursor movement,
+ * mouse movement, etc.
+ *
+ * Userspace buffering isn't required, since ANSI escape sequences and
+ * UTF-8 are decoded without peeking. Noncanonical overlong encodings
+ * can cause the stream to go out of sync. This function recovers such
+ * events by ignoring continuation bytes at the beginning of each read.
+ *
+ * String control sequences, e.g. "\e_hello\e\\" currently are not
+ * tokenized as a single read. Lastly note, this function has limited
+ * support for UNICODE representations of C0/C1 control codes, e.g.
+ *
+ *   "\000"            NUL
+ *   "\300\200"        NUL
+ *   "\302\233A"       CURSOR UP
+ *
+ * @param buf is guaranteed to receive a NUL terminator if size>0
+ * @return number of bytes read (helps differentiate "\0" vs. "")
+ * @see examples/ttyinfo.c
+ * @see ANSI X3.64-1979
+ * @see ISO/IEC 6429
+ * @see FIPS-86
+ * @see ECMA-48
+ */
+ssize_t readansi(int fd, char *buf, size_t size) {
+  int i, j;
+  uint8_t c;
+  enum { kAscii, kUtf8, kEsc, kCsi, kSs } t;
+  if (size) buf[0] = 0;
+  for (j = i = 0, t = kAscii;;) {
+    if (i + 2 >= size) return enomem();
+    if (read(fd, &c, 1) != 1) return -1;
+    buf[i++] = c;
+    buf[i] = 0;
+    switch (t) {
+      case kAscii:
+        if (c < 0200) {
+          if (c == '\e') {
+            t = kEsc;
+          } else {
+            return i;
+          }
+        } else if (c >= 0300) {
+          t = kUtf8;
+          j = ThomPikeLen(c) - 1;
+        }
+        break;
+      case kUtf8:
+        if (!--j) return i;
+        break;
+      case kEsc:
+        switch (c) {
+          case '[':
+            t = kCsi;
+            break;
+          case 'N':
+          case 'O':
+            t = kSs;
+            break;
+          case 0x20 ... 0x2F:
+            break;
+          default:
+            return i;
+        }
+        break;
+      case kCsi:
+        switch (c) {
+          case ':':
+          case ';':
+          case '<':
+          case '=':
+          case '>':
+          case '?':
+          case '0' ... '9':
+            break;
+          default:
+            return i;
+        }
+        break;
+      case kSs:
+        return i;
+      default:
+        unreachable;
+    }
+  }
+}