From 2fd8624cc612e946f593b2c9e9031c46f862562e Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Mon, 27 Apr 2015 11:13:19 -0500
Subject: Some infrastructure hexedit needs. (Poor man's curses.)

---
 lib/lib.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)

(limited to 'lib/lib.c')

diff --git a/lib/lib.c b/lib/lib.c
index 1a60a7ff..ab773b5b 100644
--- a/lib/lib.c
+++ b/lib/lib.c
@@ -637,6 +637,40 @@ int terminal_size(unsigned *xx, unsigned *yy)
   return x || y;
 }
 
+// Reset terminal to known state, saving copy of old state if old != NULL.
+int set_terminal(int fd, int raw, struct termios *old)
+{
+  struct termios termio;
+
+  // Fetch local copy of old terminfo, and copy struct contents to *old if set
+  if (!tcgetattr(fd, &termio) && old) *old = termio;
+
+  // the following are the bits set for an xterm. Linux text mode TTYs by
+  // default add two additional bits that only matter for serial processing
+  // (turn serial line break into an interrupt, and XON/XOFF flow control)
+
+  // Any key unblocks output, swap CR and NL on input
+  termio.c_iflag = IXANY|ICRNL|INLCR;
+  if (toys.which->flags & TOYFLAG_LOCALE) termio.c_iflag |= IUTF8;
+
+  // Output appends CR to NL, does magic undocumented postprocessing
+  termio.c_oflag = ONLCR|OPOST;
+
+  // Leave serial port speed alone
+  // termio.c_cflag = C_READ|CS8|EXTB;
+
+  // Generate signals, input entire line at once, echo output
+  // erase, line kill, escape control characters with ^
+  // erase line char at a time
+  // "extended" behavior: ctrl-V quotes next char, ctrl-R reprints unread chars,
+  // ctrl-W erases word
+  termio.c_lflag = ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHOCTL|ECHOKE|IEXTEN;
+
+  if (raw) cfmakeraw(&termio);
+
+  return tcsetattr(fd, TCSANOW, &termio);
+}
+
 int yesno(char *prompt, int def)
 {
   char buf;
@@ -895,3 +929,67 @@ int qstrcmp(const void *a, const void *b)
 {
   return strcmp(*(char **)a, *(char **)b);
 }
+
+int xpoll(struct pollfd *fds, int nfds, int timeout)
+{
+  int i;
+
+  for (;;) {
+    if (0>(i = poll(fds, nfds, timeout))) {
+      if (errno != EINTR && errno != ENOMEM) perror_exit("xpoll");
+      else if (timeout>0) timeout--;
+    } else return i;
+  }
+}
+
+// Scan stdin for a keypress, parsing known escape sequences
+// seq is array of char * strings, ends with NULL ptr
+// Returns: 0-255=literal, -1=EOF, -2=NONE, 256-...=index into seq
+// scratch space is necessary because last char of !seq could start new seq
+// Zero out first byte of scratch before first call to scan_key
+// block=0 allows fetching multiple characters before updating display
+int scan_key(char *scratch, char **seqs, int block)
+{
+  struct pollfd pfd;
+  int maybe, i, j;
+  char *test;
+
+  for (;;) {
+    pfd.fd = 0;
+    pfd.events = POLLIN;
+    pfd.revents = 0;
+
+    // check sequences
+    maybe = 0;
+    if (*scratch) {
+      for (i = maybe = 0; (test = seqs[i]); i++) {
+        for (j = 0; j<*scratch; j++) if (scratch[j+1] != test[j]) break;
+        if (j == *scratch) {
+          maybe = 1;
+          if (!test[j]) {
+            // We recognized current sequence: consume and return
+            *scratch = 0;
+            return 256+i;
+          }
+        }
+      }
+      // If current data can't be a known sequence, return next raw char
+      if (!maybe) break;
+    }
+
+    // Need more data to decide
+
+    // 30 miliseconds is about the gap between characters at 300 baud 
+    if (maybe || !block) if (!xpoll(&pfd, 1, 30*maybe)) break;
+
+    if (1 != read(0, scratch+1+*scratch, 1)) return -1;
+    ++*scratch;
+  }
+
+  // Was not a sequence
+  if (!*scratch) return -2;
+  i = scratch[1];
+  if (--*scratch) memmove(scratch+1, scratch+2, *scratch);
+
+  return i;
+}
-- 
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