/************************************************************
* lib_fgets.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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 Gregory Nutt 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.
*
************************************************************/
/************************************************************
* Compilation Switches
************************************************************/
/************************************************************
* Included Files
************************************************************/
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <debug.h>
/************************************************************
* Definitions
************************************************************/
/************************************************************
* Private Type Declarations
************************************************************/
/************************************************************
* Private Function Prototypes
************************************************************/
/************************************************************
* Global Function Prototypes
************************************************************/
/************************************************************
* Global Constant Data
************************************************************/
/************************************************************
* Global Variables
************************************************************/
/************************************************************
* Private Constant Data
************************************************************/
/************************************************************
* Private Variables
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/************************************************************
* Private Functions
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/************************************************************
* Name: _lib_rawgetc
************************************************************/
static inline int _lib_rawgetc(int fd)
{
char buffer;
(void)read(fd, &buffer, 1);
return buffer;
}
/************************************************************
* Name: _lib_consoleputc
************************************************************/
static inline void _lib_consoleputc(int ch)
{
char buffer = ch;
(void)write(1, &buffer, 1);
}
/************************************************************
* Name: _lib_consoleputs
************************************************************/
static inline void _lib_consoleputs(char *s)
{
(void)write(1, s, strlen(s));
}
/************************************************************
* Global Functions
************************************************************/
/************************************************************
* Name: fgets
*
* Description:
* fgets() reads in at most one less than 'n' characters
* from stream and stores them into the buffer pointed to
* by 's'. 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.
*
* Assumptions:
* If the stream corresponds to stdin (fd=0) this version
* will assume that we are reading characters from a
* VT100 console and that stdout (fd=1) is also available.
* This will not work well if fd=0 corresponds to a raw
* byte steam.
*
**********************************************************/
char *fgets(FAR char *s, int n, FILE *stream)
{
int escape = 0;
boolean console;
int nch = 0;
/* Sanity checks */
if (!stream || !s || n < 1 || stream->fs_filedes < 0)
{
return NULL;
}
if (n < 2)
{
*s = '\0';
return s;
}
/* Check if the stream is stdin */
console = (stream->fs_filedes == 0);
/* <esc>[K is the VT100 command that erases to the end of the line. */
if (console)
{
_lib_consoleputs("\033[K");
}
/* 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.
*/
for(;;)
{
/* Get the next character */
int ch = _lib_rawgetc(stream->fs_filedes);
/* Are we processing a VT100 escape sequence */
if (escape)
{
/* Yes, is it an <esc>[, 3 byte sequence */
if (ch != 0x5b || 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 */
else if (ch == 0x08)
{
/* Eliminate that last character in the buffer. */
if (nch > 0)
{
nch--;
if (console)
{
/* Echo the backspace character on the console */
_lib_consoleputc(ch);
}
}
}
/* Check for the beginning of a VT100 escape sequence */
else if (console && ch == 0x1b)
{
/* The next character is escaped */
escape = 1;
}
/* Check for end-of-line or end-of-file */
else if (ch == 0x0d)
{
/* The newline is stored in the buffer along
* with the null terminator.
*/
s[nch++] = '\n';
s[nch] = '\0';
if (console)
{
/* Echo the newline to the console */
_lib_consoleputc('\n');
}
return s;
}
/* Check for end-of-line or end-of-file */
else if (ch == EOF)
{
/* Terminate the line */
s[nch] = '\0';
return s;
}
/* Otherwise, check if the character is printable and,
* if so, put the character in the line buffer
*/
else if (isprint(ch))
{
s[nch++] = ch;
if (console)
{
/* Echo the character to the console */
_lib_consoleputc(ch);
}
/* 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 >= n)
{
s[nch] = '\0';
return s;
}
}
}
}
/************************************************************
* Name: gets
*
* Description:
* gets() reads a line from stdin into the buffer pointed
* to by s until either a terminating newline or EOF,
* which it replaces with '\0'. No check for buffer
* overrun is performed
*
**********************************************************/
/* gets() is not supported because it is inherently un-safe */
