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/*

    		 Crown Copyright (c) 1997

    This TenDRA(r) Computer Program is subject to Copyright

    owned by the United Kingdom Secretary of State for Defence

    acting through the Defence Evaluation and Research Agency

    (DERA).  It is made available to Recipients with a

    royalty-free licence for its use, reproduction, transfer

    to other parties and amendment for any purpose not excluding

    product development provided that any such use et cetera

    shall be deemed to be acceptance of the following conditions:-

        (1) Its Recipients shall ensure that this Notice is

        reproduced upon any copies or amended versions of it;

        (2) Any amended version of it shall be clearly marked to

        show both the nature of and the organisation responsible

        for the relevant amendment or amendments;

        (3) Its onward transfer from a recipient to another

        party shall be deemed to be that party's acceptance of

        these conditions;

        (4) DERA gives no warranty or assurance as to its

        quality or suitability for any purpose and DERA accepts

        no liability whatsoever in relation to any use to which

        it may be put.

*/

/**** bistream.c --- Binary input stream handling.

 *

 ** Author: Steve Folkes <smf@hermes.mod.uk>

 *

 **** Commentary:

 *

 * This file implements the binary input stream facility specified in the file

 * "bistream.h".  See that file for more details.

 *

 **** Change Log:

 * $Log: bistream.c,v $

 * Revision 1.1.1.1  1998/01/17  15:57:17  release

 * First version to be checked into rolling release.

 *

 * Revision 1.2  1994/12/12  11:45:16  smf

 * Performing changes for 'CR94_178.sid+tld-update' - bringing in line with

 * OSSG C Coding Standards.

 *

 * Revision 1.1.1.1  1994/07/25  16:06:12  smf

 * Initial import of os-interface shared files.

 *

**/

/****************************************************************************/

#include "bistream.h"

#include "cstring.h"

/*--------------------------------------------------------------------------*/

ExceptionP XX_bistream_read_error = EXCEPTION ("error reading from binary stream");

/*--------------------------------------------------------------------------*/

void

bistream_init PROTO_N ((bistream))

	      PROTO_T (BIStreamP bistream)

{

    bistream->name = NIL (CStringP);

}

BoolT

bistream_open PROTO_N ((bistream, name))

	      PROTO_T (BIStreamP bistream X

		       CStringP  name)

{

#ifdef FS_BINARY_STDIO

    if ((bistream->file = fopen (name, "rb")) == NIL (FILE *)) {

	return (FALSE);

    }

#else

    if ((bistream->file = fopen (name, "r")) == NIL (FILE *)) {

	return (FALSE);

    }

#endif /* defined (FS_BINARY_STDIO) */

    bistream->bytes = 0;

    bistream->name  = name;

    return (TRUE);

}

void

bistream_assign PROTO_N ((to, from))

		PROTO_T (BIStreamP to X

			 BIStreamP from)

{

    to->file  = from->file;

    to->bytes = from->bytes;

    to->name  = from->name;

}

BoolT

bistream_is_open PROTO_N ((bistream))

		 PROTO_T (BIStreamP bistream)

{

    return (bistream->name != NIL (CStringP));

}

unsigned

bistream_read_chars PROTO_N ((bistream, length, chars))

		    PROTO_T (BIStreamP bistream X

			     unsigned  length X

			     CStringP  chars)

{

    unsigned bytes_read = (unsigned) fread ((GenericP) chars, sizeof (char),

					    (SizeT) length, bistream->file);

    if ((bytes_read == 0) && (ferror (bistream->file))) {

	CStringP name = cstring_duplicate (bistream->name);

	THROW_VALUE (XX_bistream_read_error, name);

	UNREACHED;

    }

    bistream->bytes += bytes_read;

    return (bytes_read);

}

unsigned

bistream_read_bytes PROTO_N ((bistream, length, bytes))

		    PROTO_T (BIStreamP bistream X

			     unsigned  length X

			     ByteP     bytes)

{

    unsigned bytes_read = (unsigned) fread ((GenericP) bytes, sizeof (ByteT),

					    (SizeT) length, bistream->file);

    if ((bytes_read == 0) && (ferror (bistream->file))) {

	CStringP name = cstring_duplicate (bistream->name);

	THROW_VALUE (XX_bistream_read_error, name);

	UNREACHED;

    }

    bistream->bytes += bytes_read;

    return (bytes_read);

}

BoolT

bistream_read_byte PROTO_N ((bistream, byte_ref))

		   PROTO_T (BIStreamP bistream X

			    ByteT    *byte_ref)

{

    int byte = fgetc (bistream->file);

    if (byte == EOF) {

	if (ferror (bistream->file)) {

	    CStringP name = cstring_duplicate (bistream->name);

	    THROW_VALUE (XX_bistream_read_error, name);

	    UNREACHED;

	} else if (feof (bistream->file)) {

	    return (FALSE);

	}

    }

    bistream->bytes ++;

    *byte_ref = (ByteT) byte;

    return (TRUE);

}

unsigned

bistream_byte PROTO_N ((bistream))

	      PROTO_T (BIStreamP bistream)

{

    return (bistream->bytes);

}

CStringP

bistream_name PROTO_N ((bistream))

	      PROTO_T (BIStreamP bistream)

{

    return (bistream->name);

}

void

bistream_rewind PROTO_N ((bistream))

		PROTO_T (BIStreamP bistream)

{

#ifdef FS_ANSI_ENVIRON

    rewind (bistream->file);

#else

    (void) fseek (bistream->file, (long) 0, SEEK_SET);

#endif /* defined (FS_REWIND) */

}

void

bistream_close PROTO_N ((bistream))

	       PROTO_T (BIStreamP bistream)

{

    (void) fclose (bistream->file);

    bistream_init (bistream);

}