newlib-cygwin/newlib/libc/stdio/getdelim.c

135 lines
2.8 KiB
C

/* Copyright 2002, Red Hat Inc. - all rights reserved */
/*
FUNCTION
<<getdelim>>---read a line up to a specified line delimiter
INDEX
getdelim
SYNOPSIS
#include <stdio.h>
int getdelim(char **<[bufptr]>, size_t *<[n]>,
int <[delim]>, FILE *<[fp]>);
DESCRIPTION
<<getdelim>> reads a file <[fp]> up to and possibly including a specified
delimiter <[delim]>. The line is read into a buffer pointed to
by <[bufptr]> and designated with size *<[n]>. If the buffer is
not large enough, it will be dynamically grown by <<getdelim>>.
As the buffer is grown, the pointer to the size <[n]> will be
updated.
RETURNS
<<getdelim>> returns <<-1>> if no characters were successfully read;
otherwise, it returns the number of bytes successfully read.
At end of file, the result is nonzero.
PORTABILITY
<<getdelim>> is a glibc extension.
No supporting OS subroutines are directly required.
*/
#include <_ansi.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include "local.h"
#define MIN_LINE_SIZE 4
#define DEFAULT_LINE_SIZE 128
ssize_t
_DEFUN(__getdelim, (bufptr, n, delim, fp),
char **bufptr _AND
size_t *n _AND
int delim _AND
FILE *fp)
{
char *buf;
char *ptr;
size_t newsize, numbytes;
int pos;
int ch;
int cont;
if (fp == NULL || bufptr == NULL || n == NULL)
{
errno = EINVAL;
return -1;
}
buf = *bufptr;
if (buf == NULL || *n < MIN_LINE_SIZE)
{
buf = (char *)realloc (*bufptr, DEFAULT_LINE_SIZE);
if (buf == NULL)
{
return -1;
}
*bufptr = buf;
*n = DEFAULT_LINE_SIZE;
}
CHECK_INIT (_REENT, fp);
_newlib_flockfile_start (fp);
numbytes = *n;
ptr = buf;
cont = 1;
while (cont)
{
/* fill buffer - leaving room for nul-terminator */
while (--numbytes > 0)
{
if ((ch = getc_unlocked (fp)) == EOF)
{
cont = 0;
break;
}
else
{
*ptr++ = ch;
if (ch == delim)
{
cont = 0;
break;
}
}
}
if (cont)
{
/* Buffer is too small so reallocate a larger buffer. */
pos = ptr - buf;
newsize = (*n << 1);
buf = realloc (buf, newsize);
if (buf == NULL)
{
cont = 0;
break;
}
/* After reallocating, continue in new buffer */
*bufptr = buf;
*n = newsize;
ptr = buf + pos;
numbytes = newsize - pos;
}
}
_newlib_flockfile_end (fp);
/* if no input data, return failure */
if (ptr == buf)
return -1;
/* otherwise, nul-terminate and return number of bytes read */
*ptr = '\0';
return (ssize_t)(ptr - buf);
}