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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.

*/

/**** istream.c --- Input stream handling.

 *

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

 *

 **** Commentary:

 *

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

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

 *

 **** Change Log:

 * $Log: istream.c,v $

 * Revision 1.1.1.1  1998/01/17  15:57:18  release

 * First version to be checked into rolling release.

 *

 * Revision 1.2  1994/12/12  11:45:41  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  16:06:10  smf

 * Initial import of os-interface shared files.

 *

**/

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

#include "istream.h"

#include "cstring.h"

#include "syntax.h"

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

#define ISTREAM_BUFSIZE 8193

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

ExceptionP XX_istream_read_error = EXCEPTION ("error reading from stream");

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

static char istream_input_buffer [ISTREAM_BUFSIZE];

static IStreamT		istream_input_1 = {

    NIL (FILE *),

    &(istream_input_buffer [0]),

    &(istream_input_buffer [ISTREAM_BUFSIZE - 1]),

    &(istream_input_buffer [ISTREAM_BUFSIZE]),

    &(istream_input_buffer [ISTREAM_BUFSIZE]),

    1,

    "<stdin>",

    FALSE

};

IStreamT	 *const istream_input = &istream_input_1;

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

static IStreamStatusT

istream_read_hex_char PROTO_N ((istream, c_ref))

		      PROTO_T (IStreamP istream X

			       char    *c_ref)

{

    int value;

    int tmp;

    char c;

  redo1:

    switch (c = ISTREAM_READ_CHAR (istream)) {

      case '\0':

	ISTREAM_HANDLE_NULL (istream, redo1, eof);

	return (ISTREAM_STAT_SYNTAX_ERROR);

      case '\n':

	istream_inc_line (istream);

	return (ISTREAM_STAT_SYNTAX_ERROR);

      default:

	if (((value = syntax_value (c)) == SYNTAX_NO_VALUE) || (value >= 16)) {

	    return (ISTREAM_STAT_SYNTAX_ERROR);

	}

	tmp = value;

	break;

    }

  redo2:

    switch (c = ISTREAM_READ_CHAR (istream)) {

      case '\0':

	ISTREAM_HANDLE_NULL (istream, redo2, eof);

	return (ISTREAM_STAT_SYNTAX_ERROR);

      case '\n':

	istream_inc_line (istream);

	return (ISTREAM_STAT_SYNTAX_ERROR);

      default:

	if (((value = syntax_value (c)) == SYNTAX_NO_VALUE) || (value >= 16)) {

	    return (ISTREAM_STAT_SYNTAX_ERROR);

	}

	break;

    }

    *c_ref = (char) ((tmp * 16) + value);

    return (ISTREAM_STAT_READ_CHAR);

  eof:

    return (ISTREAM_STAT_SYNTAX_ERROR);

}

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

void

istream_setup PROTO_Z ()

{

    istream_input_1.file = stdin;

}

#ifdef FS_FAST

#undef istream_init

#endif /* defined (FS_FAST) */

void

istream_init PROTO_N ((istream))

	     PROTO_T (IStreamP istream)

{

    istream->name = NIL (CStringP);

}

#ifdef FS_FAST

#define istream_init(is) ((is)->name = NIL (CStringP))

#endif /* defined (FS_FAST) */

BoolT

istream_open PROTO_N ((istream, name))

	     PROTO_T (IStreamP istream X

		      CStringP name)

{

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

	return (FALSE);

    }

    istream->buffer  = ALLOCATE_VECTOR (char, ISTREAM_BUFSIZE);

    istream->limit   = &(istream->buffer [ISTREAM_BUFSIZE]);

    istream->line    = 1;

    istream->name    = name;

    X__istream_fill_buffer (istream);

    return (TRUE);

}

void

istream_assign PROTO_N ((to, from))

	       PROTO_T (IStreamP to X

			IStreamP from)

{

    to->file      = from->file;

    to->buffer    = from->buffer;

    to->current   = from->current;

    to->end       = from->end;

    to->limit     = from->limit;

    to->line      = from->line;

    to->name      = from->name;

    to->read_last = from->read_last;

}

#ifdef FS_FAST

#undef istream_is_open

#endif /* defined (FS_FAST) */

BoolT

istream_is_open PROTO_N ((istream))

		PROTO_T (IStreamP istream)

{

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

}

#ifdef FS_FAST

#define istream_is_open(is) ((is)->name != NIL (CStringP))

#endif /* defined (FS_FAST) */

BoolT

istream_read_char PROTO_N ((istream, c_ref))

		  PROTO_T (IStreamP istream X

			   char    *c_ref)

{

    char c;

  redo:

    switch (c = ISTREAM_READ_CHAR (istream)) {

      case '\n':

	istream_inc_line (istream);

	break;

      case '\0':

	ISTREAM_HANDLE_NULL (istream, redo, eof);

	break;

      default:

	break;

    }

    *c_ref = c;

    return (TRUE);

  eof:

    return (FALSE);

}

BoolT

istream_peek_char PROTO_N ((istream, c_ref))

		  PROTO_T (IStreamP istream X

			   char    *c_ref)

{

    char c;

  redo:

    switch (c = ISTREAM_PEEK_CHAR (istream)) {

      case '\0':

	ISTREAM_HANDLE_NULL (istream, redo, eof);

	break;

      default:

	break;

    }

    *c_ref = c;

    return (TRUE);

  eof:

    return (FALSE);

}

IStreamStatusT

istream_read_escaped_char PROTO_N ((istream, c_ref))

			  PROTO_T (IStreamP istream X

				   char    *c_ref)

{

    char c;

  redo:

    switch (c = ISTREAM_READ_CHAR (istream)) {

      case '\0':

	ISTREAM_HANDLE_NULL (istream, redo, eof);

	*c_ref = c;

	return (ISTREAM_STAT_READ_CHAR);

      case '\n':

	istream_inc_line (istream);

	return (ISTREAM_STAT_NO_CHAR);

      case '0':

	*c_ref = '\0';

	return (ISTREAM_STAT_READ_CHAR);

      case 'f': case 'F':

	*c_ref = '\f';

	return (ISTREAM_STAT_READ_CHAR);

      case 'n': case 'N':

	*c_ref = '\n';

	return (ISTREAM_STAT_READ_CHAR);

      case 'r': case 'R':

	*c_ref = '\r';

	return (ISTREAM_STAT_READ_CHAR);

      case 't': case 'T':

	*c_ref = '\t';

	return (ISTREAM_STAT_READ_CHAR);

      case 'x': case 'X':

	return (istream_read_hex_char (istream, c_ref));

      default:

	*c_ref = c;

	return (ISTREAM_STAT_READ_CHAR);

    }

  eof:

    return (ISTREAM_STAT_SYNTAX_ERROR);

}

#ifdef FS_FAST

#undef istream_inc_line

#endif /* defined (FS_FAST) */

void

istream_inc_line PROTO_N ((istream))

		 PROTO_T (IStreamP istream)

{

    istream->line ++;

}

#ifdef FS_FAST

#define istream_inc_line(is) ((is)->line ++)

#endif /* defined (FS_FAST) */

#ifdef FS_FAST

#undef istream_line

#endif /* defined (FS_FAST) */

unsigned

istream_line PROTO_N ((istream))

	     PROTO_T (IStreamP istream)

{

    return (istream->line);

}

#ifdef FS_FAST

#define istream_line(is) ((is)->line)

#endif /* defined (FS_FAST) */

#ifdef FS_FAST

#undef istream_name

#endif /* defined (FS_FAST) */

CStringP

istream_name PROTO_N ((istream))

	     PROTO_T (IStreamP istream)

{

    return (istream->name);

}

#ifdef FS_FAST

#define istream_name(is) ((is)->name)

#endif /* defined (FS_FAST) */

void

istream_close PROTO_N ((istream))

	      PROTO_T (IStreamP istream)

{

    (void) fclose (istream->file);

    if (istream != istream_input) {

	DEALLOCATE (istream->buffer);

    }

    istream_init (istream);

}

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

void

X__istream_fill_buffer PROTO_N ((istream))

		       PROTO_T (IStreamP istream)

{

    SizeT bytes = fread ((GenericP) (istream->buffer), sizeof (char),

			 (SizeT) (ISTREAM_BUFSIZE - 1), istream->file);

    if ((bytes == (SizeT) 0) && (ferror (istream->file))) {

	CStringP name = cstring_duplicate (istream->name);

	THROW_VALUE (XX_istream_read_error, name);

	UNREACHED;

    }

    istream->current   = istream->buffer;

    istream->end       = (istream->current + bytes);

    istream->read_last = FALSE;

    *(istream->end) ++ = '\0';

}