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Diffstat (limited to 'nuttx/libc/misc/lib_kbddecode.c')
| -rw-r--r-- | nuttx/libc/misc/lib_kbddecode.c | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/nuttx/libc/misc/lib_kbddecode.c b/nuttx/libc/misc/lib_kbddecode.c new file mode 100644 index 000000000..62554902c --- /dev/null +++ b/nuttx/libc/misc/lib_kbddecode.c @@ -0,0 +1,267 @@ +/**************************************************************************** + * libc/msic/lib_kbddecode.c + * Decoding side of the Keyboard CODEC + * + * Copyright (C) 2012 Gregory Nutt. All rights reserved. + * Authors: Gregory Nutt <gnutt@nuttx.org> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <stdint.h> +#include <assert.h> +#include <debug.h> + +#include <nuttx/streams.h> +#include <nuttx/ascii.h> +#include <nuttx/input/kbd_codec.h> + +/**************************************************************************** + * Pre-Processor Definitions + ****************************************************************************/ + +#define NDX_ESC 0 +#define NDX_BRACKET 1 +#define NDX_CODE 2 +#define NDX_TERMINATOR 3 + +#define NCH_ESC 1 +#define NCH_BRACKET 2 +#define NCH_CODE 3 +#define NCH_TERMINATOR 4 + +#define TERM_MIN ('a' + KBD_RELEASE) +#define TERM_MAX ('a' + KBD_SPECREL) +#define TERM_RETURN(a) ((a) - 'a') + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: kbd_reget + * + * Description: + * We have unused characters from the last, unsuccessful. Return one of + * these instead of the . + * + * Input Parameters: + * stream - An instance of lib_instream_s to do the low-level get + * operation. + * pch - The location character to save the returned value. This may be + * either a normal, character code or a special command from enum + * kbd_keycode_e + * + * Returned Value: + * KBD_PRESS - Indicates the successful receipt of norma keyboard data. + * + ****************************************************************************/ + +static int kbd_reget(FAR struct kbd_getstate_s *state, FAR uint8_t *pch) +{ + /* Return the next character */ + + *pch = state->buf[state->ndx]; + state->ndx++; + state->nch--; + return KBD_PRESS; +} + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: kbd_decode + * + * Description: + * Get one byte of data or special command from the driver provided input + * buffer. + * + * Input Parameters: + * stream - An instance of lib_instream_s to do the low-level get + * operation. + * pch - The location to save the returned value. This may be + * either a normal, character code or a special command from enum + * kbd_keycode_e + * state - A user provided buffer to support parsing. This structure + * should be cleared the first time that kbd_decode is called. + * + * Returned Value: + * + * KBD_PRESS - Indicates the successful receipt of normal, keyboard data. + * This corresponds to a keypress event. The returned value in pch is a + * simple byte of text or control data corresponding to the pressed key. + * KBD_RELEASE - Indicates a key release event. The returned value in pch + * is the byte of text or control data corresponding to the released key. + * KBD_SPECPRESS - Indicates the successful receipt of a special keyboard + * command. The returned value in pch is a value from enum kbd_getstate_s. + * KBD_SPECREL - Indicates a special key release event. The returned value + * in pch is a value from enum kbd_getstate_s. + * EOF - An error has getting the next character (reported by the stream). + * Normally indicates the end of file. + * + ****************************************************************************/ + +int kbd_decode(FAR struct lib_instream_s *stream, + FAR struct kbd_getstate_s *state, FAR uint8_t *pch) +{ + int ch; + + DEBUGASSERT(stream && state && pch); + + /* Are their ungotten characters from the last, failed parse? */ + + if (state->nch > 0) + { + /* Yes, return the next ungotten character */ + + return kbd_reget(state, pch); + } + + state->ndx = 0; + + /* No, ungotten characters. Check for the beginning of an ESC sequence. */ + + ch = stream->get(stream); + if (ch == EOF) + { + /* End of file/stream */ + + return KBD_ERROR; + } + else + { + state->buf[NDX_ESC] = (uint8_t)ch; + state->nch = NCH_ESC; + + if (ch != ASCII_ESC) + { + /* Not the beginning of an escape sequence. Return the character. */ + + return kbd_reget(state, pch); + } + } + + /* Check for ESC-[ */ + + ch = stream->get(stream); + if (ch == EOF) + { + /* End of file/stream. Return the escape character now. We will + * return the EOF indication next time. + */ + + return kbd_reget(state, pch); + } + else + { + state->buf[NDX_BRACKET] = ch; + state->nch = NCH_BRACKET; + + if (ch != '[') + { + /* Not the beginning of an escape sequence. Return the ESC now, + * return the following character later. + */ + + return kbd_reget(state, pch); + } + } + + /* Get and verify the special keyboard data to decode */ + + ch = stream->get(stream); + if (ch == EOF) + { + /* End of file/stream. Unget everything and return the ESC character. + */ + + return kbd_reget(state, pch); + } + else + { + state->buf[NDX_CODE] = (uint8_t)ch; + state->nch = NCH_CODE; + + /* Check for a valid special command code */ + + if (ch < FIRST_KEYCODE || ch > LAST_KEYCODE) + { + /* Not a special command code, return the ESC now and the next two + * characters later. + */ + + return kbd_reget(state, pch); + } + } + + /* Check for the final semicolon */ + + ch = stream->get(stream); + if (ch == EOF) + { + /* End of file/stream. Unget everything and return the ESC character. + */ + + return kbd_reget(state, pch); + } + else + { + state->buf[NDX_TERMINATOR] = (uint8_t)ch; + state->nch = NCH_TERMINATOR; + + /* Check for a valid special command code */ + + if (ch < TERM_MIN || ch > TERM_MAX) + { + /* Not a special command code, return the ESC now and the next two + * characters later. + */ + + return kbd_reget(state, pch); + } + } + + /* We have successfully parsed the the entire escape sequence. Return the + * keyboard value in pch and the value an indication determined by the + * terminating character. + */ + + *pch = state->buf[NDX_CODE]; + state->nch = 0; + return TERM_RETURN(state->buf[NDX_TERMINATOR]); +} + |