/**************************************************************************** * apps/system/readline/readline.c * * Copyright (C) 2007-2008, 2011-2012 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 /**************************************************************************** * Definitions ****************************************************************************/ /* In some systems, the underlying serial logic may automatically echo * characters back to the console. We will assume that that is not the case & here */ #define CONFIG_READLINE_ECHO 1 /* Some environments may return CR as end-of-line, others LF, and others * both. If not specified, the logic here assumes either (but not both) as * the default. */ #if defined(CONFIG_EOL_IS_CR) # undef CONFIG_EOL_IS_LF # undef CONFIG_EOL_IS_BOTH_CRLF # undef CONFIG_EOL_IS_EITHER_CRLF #elif defined(CONFIG_EOL_IS_LF) # undef CONFIG_EOL_IS_CR # undef CONFIG_EOL_IS_BOTH_CRLF # undef CONFIG_EOL_IS_EITHER_CRLF #elif defined(CONFIG_EOL_IS_BOTH_CRLF) # undef CONFIG_EOL_IS_CR # undef CONFIG_EOL_IS_LF # undef CONFIG_EOL_IS_EITHER_CRLF #elif defined(CONFIG_EOL_IS_EITHER_CRLF) # undef CONFIG_EOL_IS_CR # undef CONFIG_EOL_IS_LF # undef CONFIG_EOL_IS_BOTH_CRLF #else # undef CONFIG_EOL_IS_CR # undef CONFIG_EOL_IS_LF # undef CONFIG_EOL_IS_BOTH_CRLF # define CONFIG_EOL_IS_EITHER_CRLF 1 #endif /**************************************************************************** * 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 ****************************************************************************/ /**************************************************************************** * Name: readline_rawgetc ****************************************************************************/ static inline int readline_rawgetc(int infd) { char buffer; ssize_t nread; /* Loop until we successfully read a character (or until an unexpected * error occurs). */ do { /* Read one character from the incoming stream */ nread = read(infd, &buffer, 1); /* Return EOF if the end of file (0) or error (-1) occurs. */ if (nread < 1) { /* EINTR is not really an error; it simply means that a signal we * received while watiing for intput. */ if (nread == 0 || errno != EINTR) { return EOF; } } } while (nread < 1); /* On success, returnt he character that was read */ return (int)buffer; } /**************************************************************************** * Name: readline_consoleputc ****************************************************************************/ #ifdef CONFIG_READLINE_ECHO static inline void readline_consoleputc(int ch, int outfd) { char buffer = ch; ssize_t nwritten; /* Loop until we successfully write a character (or until an unexpected * error occurs). */ do { /* Write the character to the outgoing stream */ nwritten = write(outfd, &buffer, 1); /* Check for irrecoverable write errors. */ if (nwritten < 0 && errno != EINTR) { break; } } while (nwritten < 1); } #endif /**************************************************************************** * Name: readline_consolewrite ****************************************************************************/ #ifdef CONFIG_READLINE_ECHO static inline void readline_consolewrite(int outfd, FAR const char *buffer, size_t buflen) { (void)write(outfd, buffer, buflen); } #endif /**************************************************************************** * Global Functions ****************************************************************************/ /**************************************************************************** * Name: readline * * 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. * A length of zero would indicate an end of file condition. On failure, * a negated errno value is returned. * **************************************************************************/ ssize_t readline(FAR char *buf, int buflen, FILE *instream, FILE *outstream) { int infd; int outfd; int escape; int nch; /* Sanity checks */ if (!instream || !outstream || !buf || buflen < 1) { return -EINVAL; } if (buflen < 2) { *buf = '\0'; return 0; } /* Extract the file descriptions. This is cheating (and horribly non- * standard) */ infd = instream->fs_filedes; outfd = outstream->fs_filedes; /* [K is the VT100 command that erases to the end of the line. */ #ifdef CONFIG_READLINE_ECHO readline_consolewrite(outfd, 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 */ int ch = readline_rawgetc(infd); /* Are we processing a VT100 escape sequence */ 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. */ readline_consoleputc(ASCII_BS, outfd); readline_consolewrite(outfd, 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 */ readline_consoleputc('\n', outfd); #endif return nch; } /* Check for end-of-file */ else if (ch == EOF) { /* Terminate the line (which might be zero length) */ buf[nch] = '\0'; 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 */ readline_consoleputc(ch, outfd); #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; } } } }