/**************************************************************************** * apps/system/readline/readline_common.c * * Copyright (C) 2007-2008, 2011-2013 Gregory Nutt. All rights reserved. * Author: 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 #include #include #include #include #include "readline.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /**************************************************************************** * Private Type Declarations ****************************************************************************/ /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /**************************************************************************** * Public Data ****************************************************************************/ /**************************************************************************** * Private Data ****************************************************************************/ /* [K is the VT100 command erases to the end of the line. */ static const char g_erasetoeol[] = VT100_CLEAREOL; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: readline_common * * readline() reads in at most one less than 'buflen' characters from * 'instream' and stores them into the buffer pointed to by 'buf'. * Characters are echoed on 'outstream'. Reading stops after an EOF or a * newline. If a newline is read, it is stored into the buffer. A null * terminator is stored after the last character in the buffer. * * This version of realine assumes that we are reading and writing to * a VT100 console. This will not work well if 'instream' or 'outstream' * corresponds to a raw byte steam. * * This function is inspired by the GNU readline but is an entirely * different creature. * * Input Parameters: * buf - The user allocated buffer to be filled. * buflen - the size of the buffer. * instream - The stream to read characters from * outstream - The stream to each characters to. * * Returned values: * On success, the (positive) number of bytes transferred is returned. * EOF is returned to indicate either an end of file condition or a * failure. * **************************************************************************/ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, int buflen) { int escape; int nch; /* Sanity checks */ DEBUGASSERT(buf && buflen > 0); if (buflen < 2) { *buf = '\0'; return 0; } /* [K is the VT100 command that erases to the end of the line. */ #ifdef CONFIG_READLINE_ECHO RL_WRITE(vtbl, g_erasetoeol, sizeof(g_erasetoeol)); #endif /* Read characters until we have a full line. On each the loop we must * be assured that there are two free bytes in the line buffer: One for * the next character and one for the null terminator. */ escape = 0; nch = 0; for (;;) { /* Get the next character. readline_rawgetc() returns EOF on any * errors or at the end of file. */ int ch = RL_GETC(vtbl); /* Check for end-of-file or read error */ if (ch == EOF) { /* Did we already received some data? */ if (nch > 0) { /* Yes.. Terminate the line (which might be zero length) * and return the data that was received. The end-of-file * or error condition will be reported next time. */ buf[nch] = '\0'; return nch; } return EOF; } /* Are we processing a VT100 escape sequence */ else if (escape) { /* Yes, is it an [, 3 byte sequence */ if (ch != ASCII_LBRACKET || escape == 2) { /* We are finished with the escape sequence */ escape = 0; ch = 'a'; } else { /* The next character is the end of a 3-byte sequence. * NOTE: Some of the [ sequences are longer than * 3-bytes, but I have not encountered any in normal use * yet and, so, have not provided the decoding logic. */ escape = 2; } } /* Check for backspace * * There are several notions of backspace, for an elaborate summary see * http://www.ibb.net/~anne/keyboard.html. There is no clean solution. * Here both DEL and backspace are treated like backspace here. The * Unix/Linux screen terminal by default outputs DEL (0x7f) when the * backspace key is pressed. */ else if (ch == ASCII_BS || ch == ASCII_DEL) { /* Eliminate that last character in the buffer. */ if (nch > 0) { nch--; #ifdef CONFIG_READLINE_ECHO /* Echo the backspace character on the console. Always output * the backspace character because the VT100 terminal doesn't * understand DEL properly. */ RL_PUTC(vtbl, ASCII_BS); RL_WRITE(vtbl, g_erasetoeol, sizeof(g_erasetoeol)); #endif } } /* Check for the beginning of a VT100 escape sequence */ else if (ch == ASCII_ESC) { /* The next character is escaped */ escape = 1; } /* Check for end-of-line. This is tricky only in that some * environments may return CR as end-of-line, others LF, and * others both. */ #if defined(CONFIG_EOL_IS_LF) || defined(CONFIG_EOL_IS_BOTH_CRLF) else if (ch == '\n') #elif defined(CONFIG_EOL_IS_CR) else if (ch == '\r') #elif CONFIG_EOL_IS_EITHER_CRLF else if (ch == '\n' || ch == '\r') #endif { /* The newline is stored in the buffer along with the null * terminator. */ buf[nch++] = '\n'; buf[nch] = '\0'; #ifdef CONFIG_READLINE_ECHO /* Echo the newline to the console */ RL_PUTC(vtbl, '\n'); #endif return nch; } /* Otherwise, check if the character is printable and, if so, put the * character in the line buffer */ else if (isprint(ch)) { buf[nch++] = ch; #ifdef CONFIG_READLINE_ECHO /* Echo the character to the console */ RL_PUTC(vtbl, ch); #endif /* Check if there is room for another character and the line's * null terminator. If not then we have to end the line now. */ if (nch + 1 >= buflen) { buf[nch] = '\0'; return nch; } } } }