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/* file-input.c: file reading routines for binary files in BigEndian
order, 2's complement representation.
Copyright (C) 1992, 2011 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "config.h"
#include "file-input.h"
one_byte
get_byte (FILE *f, string filename)
{
one_byte b;
if (fread (&b, 1, 1, f) != 1)
FATAL_PERROR (concat3 ("get_byte (", filename, ")"));
return b;
}
two_bytes
get_two (FILE *f, string filename)
{
two_bytes b;
b = get_byte (f, filename) << 8;
b |= get_byte (f, filename);
return b;
}
four_bytes
get_four (FILE *f, string filename)
{
four_bytes b;
b = get_byte (f, filename) << 24;
b |= get_byte (f, filename) << 16;
b |= get_byte (f, filename) << 8;
b |= get_byte (f, filename);
return b;
}
/* In order to get a signed value, we merely read an unsigned value and
cast it; the value in the file is assumed to be 2's complement. */
signed_4_bytes
get_signed_four (FILE *f, string filename)
{
return (signed_4_bytes) get_four (f, filename);
}
/* Return the next N bytes in the file F as an array. */
address
get_n_bytes (unsigned n, FILE *f, string filename)
{
one_byte *b;
if (n == 0)
FATAL1 ("get_n_bytes (%s): can't get zero bytes", filename);
b = xmalloc (n);
if (fread (b, n, 1, f) != 1)
FATAL2 ("get_n_bytes (%s): fread of %u bytes failed", filename, n);
return b;
}
/* Reading backwards. This macro is shared among all the routines by assuming
the name `f' for the file pointer. */
#define MOVE_BACK(size) xfseek (f, (long) -size, SEEK_CUR, filename)
one_byte
get_previous_byte (FILE *f, string filename)
{
one_byte b;
MOVE_BACK (1);
b = get_byte (f, filename);
MOVE_BACK (1);
return b;
}
two_bytes
get_previous_two (FILE *f, string filename)
{
two_bytes b;
MOVE_BACK (2);
b = get_two (f, filename);
MOVE_BACK (2);
return b;
}
four_bytes
get_previous_four (FILE *f, string filename)
{
four_bytes b;
MOVE_BACK (4);
b = get_four (f, filename);
MOVE_BACK (4);
return b;
}
/* Looking for specific values in the input. */
void
match_byte (one_byte expected, FILE *f, string filename)
{
one_byte b = get_byte (f, filename);
if (b != expected)
FATAL3 ("%s: Expected byte value %u, found %u", filename, expected, b);
}
void
match_previous_byte (one_byte expected, FILE *f, string filename)
{
one_byte b = get_previous_byte (f, filename);
if (b != expected)
FATAL3 ("%s: Expected previous byte value %u, found %u", filename,
expected, b);
}
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