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Diffstat (limited to 'apps/system/readline/readline.c')
-rw-r--r-- | apps/system/readline/readline.c | 404 |
1 files changed, 404 insertions, 0 deletions
diff --git a/apps/system/readline/readline.c b/apps/system/readline/readline.c new file mode 100644 index 000000000..ec2dc1c0a --- /dev/null +++ b/apps/system/readline/readline.c @@ -0,0 +1,404 @@ +/**************************************************************************** + * lib/stdio/lib_fgets.c + * + * Copyright (C) 2007-2008, 2011-2012 Gregory Nutt. All rights reserved. + * Author: 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 <stdbool.h> +#include <stdio.h> +#include <unistd.h> +#include <string.h> +#include <ctype.h> +#include <errno.h> +#include <debug.h> + +#include <nuttx/ascii.h> +#include <nuttx/vt100.h> + +#include <apps/readline.h> + +/**************************************************************************** + * 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 + ****************************************************************************/ +/* <esc>[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; + + /* <esc>[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 <esc>[, 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 <esc>[ 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; + } + } + } +} + |