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/* Copyright (C) 1991, 1992 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <ansidecl.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#define default_func __default_room_functions.__input
/* Read NMEMB chunks of SIZE bytes each from STREAM into P. */
size_t
DEFUN(fread, (p, size, nmemb, stream),
PTR p AND size_t size AND size_t nmemb AND register FILE *stream)
{
register char *ptr = (char *) p;
register size_t to_read = size * nmemb;
size_t bytes = to_read;
if (!__validfp(stream) || !stream->__mode.__read)
{
errno = EINVAL;
return 0;
}
if (feof(stream) || ferror(stream))
return 0;
if (p == NULL || to_read == 0)
return 0;
if (!stream->__seen || stream->__buffer == NULL || stream->__pushed_back)
{
/* This stream has never been seen before, or it has a character
pushed back. Call __fillbf to deal with those cases. Life will
be simpler after this call. */
int c = __fillbf(stream);
if (c == EOF)
return 0;
*ptr++ = c;
if (--to_read == 0)
return 1;
}
read_from_buffer:;
if (stream->__bufp < stream->__get_limit)
{
/* First off, empty out the buffer. */
register size_t copy = stream->__get_limit - stream->__bufp;
if (copy > to_read)
copy = to_read;
to_read -= copy;
if (copy > 20)
memcpy((PTR) ptr, (PTR) stream->__bufp, copy);
else
{
register size_t i;
for (i = 0; i < copy; ++i)
ptr[i] = stream->__bufp[i];
}
stream->__bufp += copy;
if (to_read == 0)
return nmemb;
ptr += copy;
}
/* Reading directly into the user's buffer doesn't help when
using a user-specified input buffer filling/expanding function,
so we don't do it in that case. */
if (to_read >= stream->__bufsize &&
stream->__room_funcs.__input == default_func &&
stream->__offset == stream->__target)
{
/* Read directly into the user's buffer. */
if (stream->__io_funcs.__read != NULL)
while (to_read > 0)
{
register int count;
count = (*stream->__io_funcs.__read)(stream->__cookie,
ptr, to_read);
if (count > 0)
{
to_read -= count;
stream->__offset += count;
stream->__target += count;
ptr += count;
}
else if (count == 0)
{
stream->__eof = 1;
break;
}
else
{
stream->__error = 1;
break;
}
}
else
stream->__eof = 1;
}
else
{
int c = __fillbf(stream);
if (c == EOF)
return (bytes - to_read) / size;
*ptr++ = (char) c;
--to_read;
if (to_read > 0)
goto read_from_buffer;
}
return (bytes - to_read) / size;
}
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