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343 lines
9.7 KiB
343 lines
9.7 KiB
/**************************************************************************** |
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* lib/stdio/lib_fgets.c |
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* |
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* Copyright (C) 2007-2008, 2011-2012 Gregory Nutt. All rights reserved. |
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* Author: Gregory Nutt <gnutt@nuttx.org> |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* 3. Neither the name NuttX nor the names of its contributors may be |
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* used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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* |
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****************************************************************************/ |
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/**************************************************************************** |
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* Included Files |
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****************************************************************************/ |
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#include <nuttx/config.h> |
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#include <stdbool.h> |
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#include <stdio.h> |
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#include <unistd.h> |
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#include <string.h> |
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#include <ctype.h> |
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#include <debug.h> |
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/**************************************************************************** |
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* Definitions |
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****************************************************************************/ |
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/* In some systems, the underlying serial logic may |
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* automatically echo characters back to the console. We |
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* will assume that that is not the case here |
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*/ |
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#define CONFIG_FGETS_ECHO 1 |
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/* Some environments may return CR as end-of-line, others LF, and |
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* others both. The logic here assumes either but not both. |
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*/ |
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#undef CONFIG_EOL_IS_CR |
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#undef CONFIG_EOL_IS_LF |
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#undef CONFIG_EOL_IS_BOTH_CRLF |
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#define CONFIG_EOL_IS_EITHER_CRLF 1 |
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/**************************************************************************** |
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* Private Type Declarations |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Function Prototypes |
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****************************************************************************/ |
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/**************************************************************************** |
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* Public Data |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Data |
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****************************************************************************/ |
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/* <esc>[K is the VT100 command erases to the end of the line. */ |
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static const char g_erasetoeol[] = "\033[K"; |
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/**************************************************************************** |
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* Private Functions |
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****************************************************************************/ |
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/**************************************************************************** |
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* Name: _lib_rawgetc |
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****************************************************************************/ |
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static inline int _lib_rawgetc(int fd) |
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{ |
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char buffer; |
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ssize_t nread; |
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nread = read(fd, &buffer, 1); |
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if (nread < 1) |
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{ |
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/* Return EOF if the end of file (0) or error (-1) occurs */ |
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return EOF; |
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} |
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return (int)buffer; |
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} |
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/**************************************************************************** |
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* Name: _lib_consoleputc |
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****************************************************************************/ |
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#ifdef CONFIG_FGETS_ECHO |
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static inline void _lib_consoleputc(int ch) |
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{ |
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char buffer = ch; |
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(void)write(1, &buffer, 1); |
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} |
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#endif |
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/**************************************************************************** |
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* Name: _lib_consoleputs |
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****************************************************************************/ |
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#ifdef CONFIG_FGETS_ECHO |
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static inline void _lib_consoleputs(FAR const char *str) |
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{ |
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(void)write(1, str, strlen(str)); |
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} |
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#endif |
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/**************************************************************************** |
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* Global Functions |
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****************************************************************************/ |
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/**************************************************************************** |
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* Name: fgets |
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* |
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* Description: |
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* fgets() reads in at most one less than 'buflen' characters |
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* from stream and stores them into the buffer pointed to |
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* by 'buf'. Reading stops after an EOF or a newline. If a |
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* newline is read, it is stored into the buffer. A null |
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* terminator is stored after the last character in the |
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* buffer. |
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* |
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* Assumptions: |
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* If the stream corresponds to stdin (fd=0) this version |
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* will assume that we are reading characters from a |
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* VT100 console and that stdout (fd=1) is also available. |
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* This will not work well if fd=0 corresponds to a raw |
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* byte steam. |
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* |
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**************************************************************************/ |
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char *fgets(FAR char *buf, int buflen, FILE *stream) |
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{ |
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#ifdef CONFIG_FGETS_ECHO |
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bool console; |
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#endif |
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int escape = 0; |
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int nch = 0; |
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/* Sanity checks */ |
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if (!stream || !buf || buflen < 1 || stream->fs_filedes < 0) |
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{ |
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return NULL; |
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} |
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if (buflen < 2) |
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{ |
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*buf = '\0'; |
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return buf; |
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} |
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/* Check if the stream is stdin */ |
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#ifdef CONFIG_FGETS_ECHO |
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console = (stream->fs_filedes == 0); |
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/* <esc>[K is the VT100 command that erases to the end of the line. */ |
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if (console) |
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{ |
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_lib_consoleputs(g_erasetoeol); |
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} |
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#endif |
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/* Read characters until we have a full line. On each |
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* the loop we must be assured that there are two free bytes |
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* in the line buffer: One for the next character and one for |
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* the null terminator. |
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*/ |
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for(;;) |
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{ |
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/* Get the next character */ |
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int ch = _lib_rawgetc(stream->fs_filedes); |
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/* Are we processing a VT100 escape sequence */ |
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if (escape) |
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{ |
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/* Yes, is it an <esc>[, 3 byte sequence */ |
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if (ch != 0x5b || escape == 2) |
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{ |
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/* We are finished with the escape sequence */ |
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escape = 0; |
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ch = 'a'; |
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} |
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else |
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{ |
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/* The next character is the end of a 3-byte sequence. |
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* NOTE: Some of the <esc>[ sequences are longer than |
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* 3-bytes, but I have not encountered any in normal use |
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* yet and, so, have not provided the decoding logic. |
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*/ |
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escape = 2; |
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} |
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} |
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/* Check for backspace */ |
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else if (ch == 0x08) |
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{ |
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/* Eliminate that last character in the buffer. */ |
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if (nch > 0) |
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{ |
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nch--; |
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#ifdef CONFIG_FGETS_ECHO |
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if (console) |
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{ |
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/* Echo the backspace character on the console */ |
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_lib_consoleputc(ch); |
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_lib_consoleputs(g_erasetoeol); |
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} |
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#endif |
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} |
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} |
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/* Check for the beginning of a VT100 escape sequence */ |
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else if (console && ch == 0x1b) |
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{ |
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/* The next character is escaped */ |
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escape = 1; |
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} |
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/* Check for end-of-line. This is tricky only in that some |
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* environments may return CR as end-of-line, others LF, and |
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* others both. |
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*/ |
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#if defined(CONFIG_EOL_IS_LF) || defined(CONFIG_EOL_IS_BOTH_CRLF) |
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else if (ch == '\n') |
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#elif defined(CONFIG_EOL_IS_CR) |
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else if (ch == '\r') |
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#elif CONFIG_EOL_IS_EITHER_CRLF |
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else if (ch == '\n' || ch == '\r') |
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#endif |
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{ |
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/* The newline is stored in the buffer along |
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* with the null terminator. |
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*/ |
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buf[nch++] = '\n'; |
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buf[nch] = '\0'; |
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#ifdef CONFIG_FGETS_ECHO |
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if (console) |
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{ |
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/* Echo the newline to the console */ |
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_lib_consoleputc('\n'); |
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} |
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#endif |
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return buf; |
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} |
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/* Check for end-of-file */ |
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else if (ch == EOF) |
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{ |
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/* End of file with no data? */ |
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if (!nch) |
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{ |
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/* Yes.. return NULL as the end of file mark */ |
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return NULL; |
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} |
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else |
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{ |
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/* Terminate the line */ |
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buf[nch] = '\0'; |
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return buf; |
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} |
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} |
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/* Otherwise, check if the character is printable and, |
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* if so, put the character in the line buffer |
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*/ |
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else if (isprint(ch)) |
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{ |
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buf[nch++] = ch; |
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#ifdef CONFIG_FGETS_ECHO |
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if (console) |
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{ |
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/* Echo the character to the console */ |
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_lib_consoleputc(ch); |
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} |
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#endif |
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/* Check if there is room for another character |
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* and the line's null terminator. If not then |
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* we have to end the line now. |
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*/ |
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if (nch + 1 >= buflen) |
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{ |
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buf[nch] = '\0'; |
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return buf; |
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} |
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} |
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} |
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} |
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