268 lines
8.1 KiB
C
268 lines
8.1 KiB
C
/****************************************************************************
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* libc/msic/lib_kbddecode.c
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* Decoding side of the Keyboard CODEC
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*
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* Copyright (C) 2012 Gregory Nutt. All rights reserved.
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* Authors: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/streams.h>
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#include <nuttx/ascii.h>
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#include <nuttx/input/kbd_codec.h>
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/****************************************************************************
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* Pre-Processor Definitions
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****************************************************************************/
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#define NDX_ESC 0
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#define NDX_BRACKET 1
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#define NDX_CODE 2
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#define NDX_TERMINATOR 3
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#define NCH_ESC 1
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#define NCH_BRACKET 2
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#define NCH_CODE 3
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#define NCH_TERMINATOR 4
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#define TERM_MIN ('a' + KBD_RELEASE)
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#define TERM_MAX ('a' + KBD_SPECREL)
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#define TERM_RETURN(a) ((a) - 'a')
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: kbd_reget
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*
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* Description:
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* We have unused characters from the last, unsuccessful. Return one of
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* these instead of the .
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*
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* Input Parameters:
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* stream - An instance of lib_instream_s to do the low-level get
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* operation.
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* pch - The location character to save the returned value. This may be
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* either a normal, character code or a special command from enum
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* kbd_keycode_e
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*
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* Returned Value:
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* KBD_PRESS - Indicates the successful receipt of norma keyboard data.
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*
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****************************************************************************/
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static int kbd_reget(FAR struct kbd_getstate_s *state, FAR uint8_t *pch)
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{
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/* Return the next character */
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*pch = state->buf[state->ndx];
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state->ndx++;
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state->nch--;
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return KBD_PRESS;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: kbd_decode
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*
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* Description:
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* Get one byte of data or special command from the driver provided input
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* buffer.
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*
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* Input Parameters:
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* stream - An instance of lib_instream_s to do the low-level get
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* operation.
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* pch - The location to save the returned value. This may be
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* either a normal, character code or a special command from enum
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* kbd_keycode_e
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* state - A user provided buffer to support parsing. This structure
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* should be cleared the first time that kbd_decode is called.
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*
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* Returned Value:
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*
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* KBD_PRESS - Indicates the successful receipt of normal, keyboard data.
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* This corresponds to a keypress event. The returned value in pch is a
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* simple byte of text or control data corresponding to the pressed key.
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* KBD_RELEASE - Indicates a key release event. The returned value in pch
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* is the byte of text or control data corresponding to the released key.
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* KBD_SPECPRESS - Indicates the successful receipt of a special keyboard
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* command. The returned value in pch is a value from enum kbd_getstate_s.
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* KBD_SPECREL - Indicates a special key release event. The returned value
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* in pch is a value from enum kbd_getstate_s.
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* EOF - An error has getting the next character (reported by the stream).
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* Normally indicates the end of file.
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*
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****************************************************************************/
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int kbd_decode(FAR struct lib_instream_s *stream,
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FAR struct kbd_getstate_s *state, FAR uint8_t *pch)
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{
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int ch;
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DEBUGASSERT(stream && state && pch);
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/* Are their ungotten characters from the last, failed parse? */
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if (state->nch > 0)
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{
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/* Yes, return the next ungotten character */
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return kbd_reget(state, pch);
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}
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state->ndx = 0;
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/* No, ungotten characters. Check for the beginning of an ESC sequence. */
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ch = stream->get(stream);
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if (ch == EOF)
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{
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/* End of file/stream */
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return KBD_ERROR;
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}
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else
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{
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state->buf[NDX_ESC] = (uint8_t)ch;
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state->nch = NCH_ESC;
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if (ch != ASCII_ESC)
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{
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/* Not the beginning of an escape sequence. Return the character. */
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return kbd_reget(state, pch);
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}
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}
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/* Check for ESC-[ */
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ch = stream->get(stream);
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if (ch == EOF)
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{
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/* End of file/stream. Return the escape character now. We will
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* return the EOF indication next time.
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*/
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return kbd_reget(state, pch);
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}
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else
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{
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state->buf[NDX_BRACKET] = ch;
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state->nch = NCH_BRACKET;
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if (ch != '[')
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{
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/* Not the beginning of an escape sequence. Return the ESC now,
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* return the following character later.
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*/
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return kbd_reget(state, pch);
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}
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}
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/* Get and verify the special keyboard data to decode */
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ch = stream->get(stream);
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if (ch == EOF)
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{
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/* End of file/stream. Unget everything and return the ESC character.
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*/
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return kbd_reget(state, pch);
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}
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else
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{
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state->buf[NDX_CODE] = (uint8_t)ch;
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state->nch = NCH_CODE;
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/* Check for a valid special command code */
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if (ch < FIRST_KEYCODE || ch > LAST_KEYCODE)
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{
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/* Not a special command code, return the ESC now and the next two
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* characters later.
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*/
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return kbd_reget(state, pch);
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}
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}
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/* Check for the final semicolon */
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ch = stream->get(stream);
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if (ch == EOF)
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{
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/* End of file/stream. Unget everything and return the ESC character.
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*/
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return kbd_reget(state, pch);
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}
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else
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{
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state->buf[NDX_TERMINATOR] = (uint8_t)ch;
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state->nch = NCH_TERMINATOR;
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/* Check for a valid special command code */
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if (ch < TERM_MIN || ch > TERM_MAX)
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{
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/* Not a special command code, return the ESC now and the next two
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* characters later.
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*/
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return kbd_reget(state, pch);
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}
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}
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/* We have successfully parsed the the entire escape sequence. Return the
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* keyboard value in pch and the value an indication determined by the
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* terminating character.
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*/
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*pch = state->buf[NDX_CODE];
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state->nch = 0;
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return TERM_RETURN(state->buf[NDX_TERMINATOR]);
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}
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