Subversion Repositories tendra.SVN

/*

 * Copyright (c) 2002-2005 The TenDRA Project <http://www.tendra.org/>.

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 * 1. Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright notice,

 *    this list of conditions and the following disclaimer in the documentation

 *    and/or other materials provided with the distribution.

 * 3. Neither the name of The TenDRA Project nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific, prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS

 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;

 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,

 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR

 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF

 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * $Id$

 */

/*

    		 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.

*/

#include "config.h"

#include "types.h"

#include "check.h"

#include "de_types.h"

#include "de_capsule.h"

#include "de_unit.h"

#include "decode.h"

#include "eval.h"

#include "fetch.h"

#include "high.h"

#include "node.h"

#include "shape.h"

#include "table.h"

#include "tdf.h"

#include "utility.h"

/*

    DECODE AN EXTENDED VALUE

    An extended n bit encoding is decoded.

*/

long

fetch_extn(int n)

{

    long r = 0, s;

    while (s = fetch(n), s == 0)r += ((1 << n) - 1);

    return(r + s);

}

/*

    DECODE A TDF INTEGER

    A TDF integer is decoded and returned as a long (no overflow checks).

*/

long

tdf_int(void)

{

    long d, n = 0;

    do {

	d = fetch(4);

	n = 8 * n + (d & 7);

    } while (!(d & 8));

    return(n);

}

/*

    DECODE A TOKEN APPLICATION

    A token application returning sort s is appended to p.  If s is

    SORT_unknown a simple token (rather than a token application) is

    read.

*/

construct *

de_token(node *p, sortname s)

{

    long bits;

    construct *t;

    tok_info *info;

    construct dummy;

    /* Find token type */

    long n = de_token_bits();

    if (n == ENC_make_tok) {

	long m = tdf_int();

	t = find_binding(crt_binding, tok_var, m);

	info = get_tok_info(t);

	p->son = new_node();

	p->son->cons = t;

    } else if (n == ENC_use_tokdef) {

	char *nm;

	t = make_construct(SORT_token);

	nm = alloc_nof(char, 32);

	IGNORE sprintf(nm, "~~token_%ld", t->encoding);

	t->name = nm;

	if (add_to_var_hash(t, SORT_token)) {

	    input_error("%s has already been defined", nm);

	}

	de_token_defn(t,(node *)null);

	info = get_tok_info(t);

	p->son = new_node();

	p->son->cons = t;

    } else {

	high_sort *h;

	construct *tt;

	tt = de_token(p, SORT_token);

	info = get_tok_info(tt);

	h = high_sorts + high_no(info->res);

	dummy.name = "high level token";

	dummy.u.tok_u.res = h->res;

	dummy.u.tok_u.args = find_decode_string(h);

	t = &dummy;

	info = &dummy.u.tok_u;

    }

    /* Quit here if only reading token */

    if (s == SORT_unknown) {

	if (!text_output) {

	    p->son->son = new_node();

	    p->son->son->cons = &token_cons;

	}

	return(null);

    }

    /* Find the length of the arguments */

    bits = tdf_int();

    if (info->res == SORT_unknown) {

	/* Unknown token */

	if (bits) {

	    /* Step over arguments */

	    char *args;

	    if (streq(t->name, "~dg_exp")) {

		args = "xFF";

	    } else if (streq(t->name, "~exp_to_source")) {

		args = "xFF";

	    } else if (streq(t->name, "~diag_id_scope")) {

		args = "x$xF";

	    } else if (streq(t->name, "~diag_type_scope")) {

		args = "x$F";

	    } else if (streq(t->name, "~diag_tag_scope")) {

		args = "x$F";

	    } else {

		warning("Token %s undeclared", t->name);

		args = "F";

	    }

	    bits += input_posn();

	    p->son->son = de_node(args);

	    bits -= input_posn();

	    if (bits < 0) {

		input_error("Token %s, arguments length wrong", t->name);

		return(t);

	    }

	    input_skip(bits);

	} else {

	    /* No argument - can deduce token sort */

	    info->res = s;

	    info->dec = 1;

	}

    } else {

	/* Known token */

	if (s == SORT_token) {

	    /* Must be high level */

	    if (!is_high(info->res)) {

		input_error("Sort error in token %s", t->name);

	    }

	} else if (info->res != s) {

	    /* Result sort must match */

	    input_error("Sort error in token %s", t->name);

	}

	if (info->args) {

	    /* Decode arguments */

	    long end_posn = input_posn() + bits;

	    p->son->son = de_node(info->args);

	    if (input_posn()!= end_posn) {

		input_error("Token %s, arguments length wrong", t->name);

		return(t);

	    }

	} else {

	    /* No arguments */

	    if (bits) {

		input_error("Token %s, arguments length wrong", t->name);

		return(t);

	    }

	}

	info->dec = 1;

    }

    /* Mark used tokens */

    if (info->dec)adjust_token(t);

    return(t);

}

/*

    DECODE A VARIABLE SORT

    A construct of the vth variable sort is decoded.

*/

node *

de_var_sort(long v)

{

    long n = tdf_int();

    node *p = new_node();

    p->cons = find_binding(crt_binding, v, n);

    return(p);

}

/*

    DECODE A LABEL

    A label construct is decoded.

*/

static void

de_make_label(node *p)

{

    long n = tdf_int();

    p->son = new_node();

    p->son->cons = find_label(n);

    return;

}

/*

    DECODE A STRING OF DECODE CHARACTERS

    The string of decode character str is decoded.

*/

node *

de_node(char *str)

{

    char c;

    node *p, *q = null, *qe = null;

    while (c = *str, c != 0 && c != ']') {

	switch (c) {

	    case '[':

	    case '{':

	    case '}':

	    case '&':

	    case '^': {

		/* Ignore these cases */

		p = null;

		break;

	    }

	    case '|': {

		/* Align input stream */

		byte_align();

		p = null;

		break;

	    }

	    case 'i': {

		/* Decode an integer as a string of octal digits */

		long d, n = 0;

		char buff[1000];

		do {

		    d = fetch(4);

		    buff[n] = (char)('0' + (d & 7));

		    n++;

		} while (!(d & 8));

		buff[n] = 0;

		p = new_node();

		p->cons = new_construct();

		if (fits_ulong(buff, 1)) {

		    p->cons->sortnum = SORT_small_tdfint;

		    p->cons->encoding = (long)octal_to_ulong(buff);

		} else {

		    p->cons->sortnum = SORT_tdfint;

		    p->cons->name = string_copy_aux(buff);

		}

		break;

	    }

	    case 'j': {

		/* Decode a bit */

		p = new_node();

		p->cons = (tdf_bool()? &true_cons : &false_cons);

		break;

	    }

	    case '$': {

		/* Decode a string */

		long i, n = tdf_int();

		if (n == 8) {

		    char *s;

		    n = tdf_int();

		    s = alloc_nof(char, n + 1);

		    p = new_node();

		    p->cons = new_construct();

		    p->cons->sortnum = SORT_tdfstring;

		    p->cons->encoding = n;

		    p->cons->name = s;

		    p->cons->next = null;

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

			s [i] = ( char ) fetch ( 8 ) ; /* LINT */

		    }

		    s[n] = 0;

		} else {

		    long m;

		    node *px;

		    p = new_node();

		    p->cons = &string_cons;

		    p->son = make_int(n);

		    m = tdf_int();

		    px = new_node();

		    px->cons = new_construct();

		    px->cons->sortnum = SORT_repeat;

		    px->cons->encoding = m;

		    p->son->bro->bro = px;

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

			long v = fetch((int)n);

			if (i == 0) {

			    px->son = make_int(v);

			    px = px->son;

			} else {

			    px->bro->bro = make_int(v);

			    px = px->bro->bro;

			}

		    }

		}

		break;

	    }

	    case '=': {

		/* Decode an aligned string */

		char *s;

		long i, n = tdf_int();

		if (n != 8)input_error("Only 8-bit strings allowed");

		n = tdf_int();

		byte_align();

		s = alloc_nof(char, n + 1);

		p = new_node();

		p->cons = new_construct();

		p->cons->sortnum = SORT_tdfstring;

		p->cons->encoding = n;

		p->cons->name = s;

		p->cons->next = null;

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

		    s [i] = ( char ) fetch ( 8 ) ; /* LINT */

		}

		s[n] = 0;

		byte_align();

		break;

	    }

	    case '*': {

		/* The following text is repeated n times */

		de_list_start();

		goto percent_case;

	    }

	    case '%':

	    percent_case : {

		/* The following text is repeated n times */

		node *pe = null;

		long i, n = tdf_int();

		p = new_node();

		p->cons = new_construct();

		p->cons->sortnum = SORT_repeat;

		p->cons->encoding = n;

		str += 2;

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

		    node *pi = de_node(str);

		    if (pe == null) {

			p->son = pi;

		    } else {

			pe->bro = pi;

		    }

		    pe = pi;

		    while (pe->bro)pe = pe->bro;

		}

		str = skip_text(str);

		break;

	    }

	    case '?': {

		/* The following text is optional */

		p = new_node();

		p->cons = &optional_cons;

		str += 2;

		if (tdf_bool()) {

		    p->son = de_node(str);

		    if (*str == '*' && p->son->cons->encoding == 0) {

			/* Get rid of optional empty lists */

			p->son = null;

		    }

		}

		str = skip_text(str);

		break;

	    }

	    case '@': {

		/* The following text is a bitstream */

		long len, pos;

		str += 2;

		len = tdf_int();

		pos = input_posn();

		p = new_node();

		p->cons = &bytestream_cons;

		p->son = de_node(str);

		if (len + pos != input_posn()) {

		    input_error("Conditional length wrong");

		}

		str = skip_text(str);

		break;

	    }

	    case 'T': {

		node dummy;

		str = find_sortname(str,(sortname *)null);

		IGNORE de_token(&dummy, SORT_unknown);

		p = dummy.son;

		break;

	    }

	    case 'F': {

		/* Unknown sort */

		p = new_node();

		p->cons = &unknown_cons;

		break;

	    }

	    default : {

		/* Basic sorts */

		sortname s = find_sort(c);

		p = (sort_decode[s])();

		break;

	    }

	}

	if (p) {

	    if (qe == null) {

		q = p;

	    } else {

		qe->bro = p;

	    }

	    qe = p;

	    while (qe->bro)qe = qe->bro;

	}

	str++;

    }

    return(q);

}