159 lines
4.4 KiB
C
159 lines
4.4 KiB
C
/* fgets.c - Read lines of text from a stream. stdio.h */
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/* Copyright 1992-1993 Wind River Systems, Inc. */
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/*
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modification history
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--------------------
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01c,05mar93,jdi documentation cleanup for 5.1.
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01b,20sep92,smb documentation additions
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01a,29jul92,jcf Added OBJ_VERIFY
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smb taken from UCB stdio
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*/
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/*
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DESCRIPTION
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*
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Chris Torek.
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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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* 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 the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be 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 REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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INCLUDE FILE: stdio.h, string.h
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SEE ALSO: American National Standard X3.159-1989
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NOMANUAL
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*/
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#include "vxWorks.h"
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#include "stdio.h"
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#include "string.h"
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#include "objLib.h"
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#include "private/stdioP.h"
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/******************************************************************************
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*
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* fgets - read a specified number of characters from a stream (ANSI)
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*
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* This routine stores in the array <buf> up to <n>-1 characters from a
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* specified stream. No additional characters are read after a new-line or
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* end-of-line. A null character is written immediately after the last
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* character read into the array.
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*
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* If end-of-file is encountered and no characters have been read, the
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* contents of the array remain unchanged. If a read error occurs, the array
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* contents are indeterminate.
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*
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* INCLUDE FILES: stdio.h
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*
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* RETURNS:
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* A pointer to <buf>, or a null pointer if an error occurs or end-of-file is
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* encountered and no characters have been read.
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*
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* SEE ALSO: fread(), fgetc()
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*/
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char * fgets
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(
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char * buf, /* where to store characters */
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FAST size_t n, /* no. of bytes to read + 1 */
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FAST FILE * fp /* stream to read from */
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)
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{
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FAST size_t len;
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FAST char * s;
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FAST uchar_t * p;
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FAST uchar_t * t;
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if (OBJ_VERIFY (fp, fpClassId) != OK)
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return (NULL);
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if (n < 2) /* sanity check */
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return (NULL);
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s = buf;
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n--; /* leave space for NULL */
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do
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{
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if ((len = fp->_r) <= 0) /* If the buffer is empty, refill it */
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{
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if (__srefill(fp)) /* EOF/error: partial or no line */
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{
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if (s == buf)
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return (NULL);
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break;
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}
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len = fp->_r;
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}
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p = fp->_p;
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/*
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* Scan through at most n bytes of the current buffer,
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* looking for '\n'. If found, copy up to and including
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* newline, and stop. Otherwise, copy entire chunk
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* and loop.
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*/
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if (len > n)
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len = n;
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t = memchr ((void *)p, '\n', len);
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if (t != NULL)
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{
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len = ++t - p;
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fp->_r -= len;
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fp->_p = t;
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(void) bcopy ((void *)p, (void *)s, len);
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s[len] = 0;
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return (buf);
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}
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fp->_r -= len;
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fp->_p += len;
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(void) bcopy ((void *)p, (void *)s, len);
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s += len;
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} while ((n -= len) != 0);
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*s = 0;
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return (buf);
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}
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