1 files changed, 158 insertions, 0 deletions
diff --git a/lib/file-input.c b/lib/file-input.c
new file mode 100644
index 0000000..1bc138b
--- /dev/null
+++ b/lib/file-input.c
@@ -0,0 +1,158 @@
+/* file-input.c: file reading routines for binary files in BigEndian
+   order, 2's complement representation.
+
+Copyright (C) 1992 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 2, 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);
+}