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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.

*/

/*** tdf-read.c --- TDF reader ADT.

 *

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

 *

 *** Commentary:

 *

 * This file implements the TDF reader routines used by the TDF linker.

 *

 *** Change Log:

 * $Log: tdf-read.c,v $

 * Revision 1.1.1.1  1998/01/17  15:57:20  release

 * First version to be checked into rolling release.

 *

 * Revision 1.3  1995/09/22  08:39:37  smf

 * Fixed problems with incomplete structures (to shut "tcc" up).

 * Fixed some problems in "name-key.c" (no real problems, but rewritten to

 * reduce the warnings that were output by "tcc" and "gcc").

 * Fixed bug CR95_354.tld-common-id-problem (library capsules could be loaded

 * more than once).

 *

 * Revision 1.2  1994/12/12  11:46:55  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  16:03:38  smf

 * Initial import of TDF linker 3.5 non shared files.

 *

**/

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

#include "tdf-read.h"

#include "gen-errors.h"

#include "ostream.h"

#include "solve-cycles.h"

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

ExceptionP XX_tdf_read_error = EXCEPTION ("error reading TDF capsule");

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

static unsigned

tdf_read_nibble PROTO_N ((reader))

		PROTO_T (TDFReaderP reader)

{

    if (reader->new_byte) {

	switch (reader->type) EXHAUSTIVE {

	  case RT_STREAM:

	    if (bistream_read_byte (&(reader->u.bistream), &(reader->byte))) {

		reader->new_byte = FALSE;

		return (((unsigned) reader->byte >> 4) & 0xF);

	    }

	    E_unexpected_eof_in_tdf (reader);

	    THROW (XX_tdf_read_error);

	    UNREACHED;

	  case RT_STRING:

	    if (reader->u.string.current < reader->u.string.limit) {

		reader->byte     = (ByteT) (*(reader->u.string.current ++));

		reader->new_byte = FALSE;

		reader->u.string.byte ++;

		return (((unsigned) reader->byte >> 4) & 0xF);

	    }

	    E_unexpected_eof_in_tdf (reader);

	    THROW (XX_tdf_read_error);

	    UNREACHED;

	}

    }

    reader->new_byte = TRUE;

    return (reader->byte & 0xF);

}

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

BoolT

tdf_reader_open PROTO_N ((reader, name))

		PROTO_T (TDFReaderP reader X

			 CStringP   name)

{

    reader->type     = RT_STREAM;

    reader->new_byte = TRUE;

    if (!bistream_open (&(reader->u.bistream), name)) {

	return (FALSE);

    }

    return (TRUE);

}

void

tdf_reader_open_string PROTO_N ((reader, name, bytes))

		       PROTO_T (TDFReaderP reader X

				CStringP   name X

				NStringP   bytes)

{

    CStringP contents = nstring_contents (bytes);

    unsigned length   = nstring_length (bytes);

    reader->type              = RT_STRING;

    reader->new_byte          = TRUE;

    reader->u.string.contents = contents;

    reader->u.string.current  = contents;

    reader->u.string.limit    = (contents + length);

    reader->u.string.name     = name;

    reader->u.string.byte     = 0;

}

CStringP

tdf_reader_name PROTO_N ((reader))

		PROTO_T (TDFReaderP reader)

{

    switch (reader->type) EXHAUSTIVE {

      case RT_STREAM:

	return (bistream_name (&(reader->u.bistream)));

      case RT_STRING:

	return (reader->u.string.name);

    }

    UNREACHED;

}

unsigned

tdf_reader_byte PROTO_N ((reader))

		PROTO_T (TDFReaderP reader)

{

    switch (reader->type) EXHAUSTIVE {

      case RT_STREAM:

	return (bistream_byte (&(reader->u.bistream)));

      case RT_STRING:

	return (reader->u.string.byte);

    }

    UNREACHED;

}

unsigned

tdf_read_int PROTO_N ((reader))

	     PROTO_T (TDFReaderP reader)

{

    unsigned value = 0;

    unsigned limit = (UINT_MAX >> 3);

    for (;;) {

	unsigned nibble = tdf_read_nibble (reader);

	if (value > limit) {

	    E_tdf_integer_too_big_in_tdf (reader);

	    THROW (XX_tdf_read_error);

	    UNREACHED;

	}

	value <<= 3;

	value |= (nibble & 0x7);

	if (nibble & 0x8) {

	    return (value);

	}

    }

}

void

tdf_read_align PROTO_N ((reader))

	       PROTO_T (TDFReaderP reader)

{

    reader->new_byte = TRUE;

}

void

tdf_read_bytes PROTO_N ((reader, nstring))

	       PROTO_T (TDFReaderP reader X

			NStringP   nstring)

{

    unsigned length   = nstring_length (nstring);

    CStringP contents = nstring_contents (nstring);

    tdf_read_align (reader);

    switch (reader->type) EXHAUSTIVE {

      case RT_STREAM:

	if (bistream_read_chars (&(reader->u.bistream), length, contents) !=

	    length) {

	    E_unexpected_eof_in_tdf (reader);

	    THROW (XX_tdf_read_error);

	    UNREACHED;

	}

	break;

      case RT_STRING:

	if ((reader->u.string.current + length) > reader->u.string.limit) {

	    E_unexpected_eof_in_tdf (reader);

	    THROW (XX_tdf_read_error);

	    UNREACHED;

	}

	nstring_insert_cstring (nstring, reader->u.string.current);

	reader->u.string.current += length;

	reader->u.string.byte    += length;

	break;

    }

}

void

tdf_read_string PROTO_N ((reader, nstring))

		PROTO_T (TDFReaderP reader X

			 NStringP   nstring)

{

    unsigned size = tdf_read_int (reader);

    unsigned length;

    if (size != 8) {

	E_unsupported_char_size_in_tdf (reader, size);

	THROW (XX_tdf_read_error);

	UNREACHED;

    }

    length = tdf_read_int (reader);

    nstring_init_length (nstring, length);

    tdf_read_bytes (reader, nstring);

}

void

tdf_read_name PROTO_N ((reader, name))

	      PROTO_T (TDFReaderP reader X

		       NameKeyP   name)

{

    unsigned type = ((tdf_read_nibble (reader) >> 2) & 0x3);

    NStringT nstring;

    unsigned components;

    unsigned i;

    tdf_read_align (reader);

    switch (type) {

      case 0x1:

	tdf_read_string (reader, &nstring);

	name_key_init_string (name, &nstring);

	break;

      case 0x2:

	components = tdf_read_int (reader);

	name_key_init_unique (name, components);

	for (i = 0; i < components; i ++) {

	    tdf_read_string (reader, &nstring);

	    name_key_set_component (name, i, &nstring);

	}

	break;

      default:

	E_bad_name_type_in_tdf (reader, type);

	THROW (XX_tdf_read_error);

	UNREACHED;

    }

}

void

tdf_read_eof PROTO_N ((reader))

	     PROTO_T (TDFReaderP reader)

{

    ByteT byte;

    switch (reader->type) EXHAUSTIVE {

      case RT_STREAM:

	if (bistream_read_byte (&(reader->u.bistream), &byte)) {

	    E_expected_eof_in_tdf (reader);

	    THROW (XX_tdf_read_error);

	    UNREACHED;

	}

	break;

      case RT_STRING:

	if (reader->u.string.current < reader->u.string.limit) {

	    E_expected_eof_in_tdf (reader);

	    THROW (XX_tdf_read_error);

	    UNREACHED;

	}

	break;

    }

}

void

tdf_reader_rewind PROTO_N ((reader))

		  PROTO_T (TDFReaderP reader)

{

    switch (reader->type) EXHAUSTIVE {

      case RT_STREAM:

	bistream_rewind (&(reader->u.bistream));

	break;

      case RT_STRING:

	reader->u.string.current = reader->u.string.contents;

	break;

    }

}

void

tdf_reader_close PROTO_N ((reader))

		 PROTO_T (TDFReaderP reader)

{

    switch (reader->type) EXHAUSTIVE {

      case RT_STREAM:

	bistream_close (&(reader->u.bistream));

	break;

      case RT_STRING:

	break;

    }

}

/*

 * Local variables(smf):

 * eval: (include::add-path-entry "../os-interface" "../library")

 * eval: (include::add-path-entry "../generated")

 * end:

**/