/******************************************************************************************** * libc/msic/lib_kbddecode.c * Decoding side of the Keyboard CODEC * * Copyright (C) 2012 Gregory Nutt. All rights reserved. * Authors: Gregory Nutt * * 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 #include #include #include #include #include /******************************************************************************************** * Pre-Processor Definitions ********************************************************************************************/ #define NDX_ESC 0 #define NDX_BRACKET 1 #define NDX_CODE 2 #define NCX_SEMICOLON 3 #define NCH_ESC 1 #define NCH_BRACKET 2 #define NCH_CODE 3 #define NCH_SEMICOLON 4 /******************************************************************************************** * 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, "in-band" ASCII characer or a special, "out-of-band" * command. * state - A user provided buffer to support parsing. This structure * should be cleared the first time that kbd_get is called. * * Returned Value: * 2 - Indicates the successful receipt of a special, "out-of-band" command * 1 - Indicates the successful receipt of normal, "in-band" ASCII data. * 0 - Indicates end-of-file or that the stream has been closed * EOF - An error has getting the next character (reported by the stream). * ****************************************************************************/ 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_NORMAL; } /******************************************************************************************** * Public Functions ********************************************************************************************/ /**************************************************************************** * Name: kbd_get * * 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 character to save the returned value. This may be * either a normal, "in-band" ASCII characer or a special, "out-of-band" * command. * state - A user provided buffer to support parsing. This structure * should be cleared the first time that kbd_get is called. * * Returned Value: * 1 - Indicates the successful receipt of a special, "out-of-band" command. * The returned value in pch is a value from enum kbd_getstate_s. * 0 - Indicates the successful receipt of normal, "in-band" ASCII data. * The returned value in pch is a simple byte of text or control data. * EOF - An error has getting the next character (reported by the stream). * Normally indicates the end of file. * ****************************************************************************/ int kbd_get(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, "out-of-band" command code */ 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[NCX_SEMICOLON] = (uint8_t)ch; state->nch = NCH_SEMICOLON; /* Check for a valid special command code */ if (ch != ';') { /* 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 * special code in pch and the value 2. */ *pch = state->buf[NDX_CODE]; state->nch = 0; return KBD_SPECIAL; }