ldiscucs.c

/*
 * ldisc.c: PuTTY line discipline. Sits between the input coming
 * from keypresses in the window, and the output channel leading to
 * the back end. Implements echo and/or local line editing,
 * depending on what's currently configured.
 */

#include <stdio.h>
#include <ctype.h>

#include "putty.h"
#include "terminal.h"
#include "ldisc.h"

void lpage_send(
    void *handle, int codepage, const char *buf, int len, int interactive)
{
  Ldisc ldisc = (Ldisc)handle;
  wchar_t *widebuffer = 0;
  int widesize = 0;
  int wclen;

  if (codepage < 0) {
    ldisc_send(ldisc, buf, len, interactive);
    return;
  }

  widesize = len * 2;
  widebuffer = snewn(widesize, wchar_t);

  wclen = mb_to_wc(codepage, 0, buf, len, widebuffer, widesize);
  luni_send(ldisc, widebuffer, wclen, interactive);

  sfree(widebuffer);
}

void luni_send(void *handle, const wchar_t *widebuf, int len, int interactive)
{
  Ldisc ldisc = (Ldisc)handle;
  int ratio = (in_utf(ldisc->term)) ? 3 : 1;
  char *linebuffer;
  int linesize;
  int i;
  char *p;

  linesize = len * ratio * 2;
  linebuffer = snewn(linesize, char);

  if (in_utf(ldisc->term)) {
    /* UTF is a simple algorithm */
    for (p = linebuffer, i = 0; i < len; i++) {
      unsigned long ch = widebuf[i];

      if (IS_SURROGATE(ch)) {
#ifdef PLATFORM_IS_UTF16
        if (i + 1 < len) {
          unsigned long ch2 = widebuf[i + 1];
          if (IS_SURROGATE_PAIR(ch, ch2)) {
            ch = FROM_SURROGATES(ch, ch2);
            i++;
          }
        } else
#endif
        {
          /* Unrecognised UTF-16 sequence */
          ch = '.';
        }
      }

      if (ch < 0x80) {
        *p++ = (char)(ch);
      } else if (ch < 0x800) {
        *p++ = (char)(0xC0 | (ch >> 6));
        *p++ = (char)(0x80 | (ch & 0x3F));
      } else if (ch < 0x10000) {
        *p++ = (char)(0xE0 | (ch >> 12));
        *p++ = (char)(0x80 | ((ch >> 6) & 0x3F));
        *p++ = (char)(0x80 | (ch & 0x3F));
      } else {
        *p++ = (char)(0xF0 | (ch >> 18));
        *p++ = (char)(0x80 | ((ch >> 12) & 0x3F));
        *p++ = (char)(0x80 | ((ch >> 6) & 0x3F));
        *p++ = (char)(0x80 | (ch & 0x3F));
      }
    }
  } else {
    int rv;
    rv = wc_to_mb(ldisc->term->ucsdata->line_codepage,
                  0,
                  widebuf,
                  len,
                  linebuffer,
                  linesize,
                  NULL,
                  NULL,
                  ldisc->term->ucsdata);
    if (rv >= 0)
      p = linebuffer + rv;
    else
      p = linebuffer;
  }
  if (p > linebuffer)
    ldisc_send(ldisc, linebuffer, p - linebuffer, interactive);

  sfree(linebuffer);
}