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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.

*/

#include "config.h"

#include "ascii.h"

#include "types.h"

#include "basic.h"

#include "capsule.h"

#include "file.h"

#include "sort.h"

#include "tdf.h"

#include "tree.h"

#include "utility.h"

/*

    READ AN EXTENDED NUMBER FROM THE INPUT FILE

    This routine reads n bits.  If these are nonzero they give the result.

    Otherwise the result is ( 2^n - 1 ) plus the next extended number.

*/

long fetch_extn

    PROTO_N ( ( n ) )

    PROTO_T ( int n )

{

    long r = 0, s ;

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

    return ( r + s ) ;

}

/*

    READ A TDF INTEGER FROM THE INPUT FILE

    This routine reads a TDF integer from the input file, returning

    the result as a long.  Any overflow is ignored.  A TDF integer

    is encoded as a series of 4 bit chunks, the least significant

    three of which represent an octal digit, and the most significant

    of which is a flag which is set to mark the last digit.

*/

long tdf_int

    PROTO_Z ()

{

    long dig ;

    long num = 0 ;

    if ( read_error ) return ( 0 ) ;

    do {

	dig = fetch ( 4 ) ;

	num = 8 * num + ( dig & 7 ) ;

    } while ( !( dig & 8 ) ) ;

    return ( num ) ;

}

/*

    BUFFER FOR LARGE TDF INTEGERS

    Larger TDF integers are stored as strings of octal digits.  This

    buffer is used to hold them temporarily.  tdf_int_digits gives

    the number of octal digits read.

*/

int tdf_int_digits ;

static char tdf_int_buff [1000] ;

/*

    READ A TDF INTEGER AS A STRING OF OCTAL DIGITS

    A TDF integer is read into the buffer tdf_int_buff, with its length being

    recorded in tdf_int_digits.

*/

char *tdf_int_str

    PROTO_Z ()

{

    long dig ;

    int i = 0 ;

    int reported = 0 ;

    if ( read_error ) {

	/* allow for recovery */

	tdf_int_digits = 1 ;

	return ( "0" ) ;

    }

    do {

	dig = fetch ( 4 ) ;

	if ( i < 1000 ) {

	    tdf_int_buff [i] = charact ( dig & 7 ) ;

	    i++ ;

	} else {

	    if ( !reported ) input_error ( "Numeric overflow" ) ;

	    reported = 1 ;

	}

    } while ( !( dig & 8 ) ) ;

    tdf_int_buff [i] = 0 ;

    tdf_int_digits = i ;

    return ( tdf_int_buff ) ;

}

/*

    READ AN 8-BIT STRING

    Only strings consisting of 8-bit characters are actually dealt with

    at the moment.  This routine decodes such a string of length n,

    translating any unprintable characters into escape sequences.

*/

string get_string

    PROTO_N ( ( n, sz ) )

    PROTO_T ( long n X long sz )

{

    long i ;

    string s ;

    char buff [5000] ;

    char *p = buff ;

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

	int c = ( int ) fetch ( ( int ) sz ) ;

	if ( printable ( c ) ) {

	    if ( c == SLASH || c == QUOTE ) *( p++ ) = SLASH ;

	    *( p++ ) = ( char ) c ;

	} else {

	    *( p++ ) = SLASH ;

	    if ( c == NEWLINE ) {

		*( p++ ) = 'n' ;

	    } else if ( c == TAB ) {

		*( p++ ) = 't' ;

	    } else {

		*( p++ ) = charact ( c / 64 ) ;

		*( p++ ) = charact ( ( c % 64 ) / 8 ) ;

		*( p++ ) = charact ( c % 8 ) ;

	    }

	}

    }

    *( p++ ) = 0 ;

    n = ( int ) ( p - buff ) ;

    s = alloc_nof ( char, n ) ;

    IGNORE memcpy ( s, buff, ( size_t ) n ) ;

    return ( s ) ;

}

/*

    DECODE A TDF STRING

    A TDF string is read and returned.  This consists of the number

    of bits per character and the string length followed by the

    appropriate number of characters.  If the character size is not 8

    or the string is too long, it is deemed to be unprintable.

*/

string de_tdfstring

    PROTO_Z ()

{

    string s ;

    long sz = tdf_int () ;

    long n = tdf_int () ;

    if ( sz == 8 && n < 1000 ) {

	s = get_string ( n, sz ) ;

    } else {

	skip_bits ( ( long ) ( n * sz ) ) ;

	s = "<UNPRINTABLE>" ;

    }

    return ( s ) ;

}

/*

    DECODE AN ALIGNED TDF STRING

    This routine is identical to that above except that there are a

    couple of alignments.  This is used by de_extern_name.

*/

string de_tdfstring_align

    PROTO_Z ()

{

    string s ;

    long sz = tdf_int () ;

    long n = tdf_int () ;

    byte_align () ;

    if ( sz == 8 && n < 1000 ) {

	s = get_string ( n, sz ) ;

    } else {

	skip_bits ( ( long ) ( n * sz ) ) ;

	s = "<UNPRINTABLE>" ;

    }

    byte_align () ;

    return ( s ) ;

}

/*

    DECODE A UNIQUE IDENTIFIER

    A unique consists of an array of strings.  The end of the array is marked

    by a null string.

*/

unique de_unique

    PROTO_Z ()

{

    long i, n ;

    unique u ;

    n = tdf_int () ;

    u = alloc_nof ( string, n + 1 ) ;

    for ( i = 0 ; i < n ; i++ ) u [i] = de_tdfstring_align () ;

    u [n] = null ;

    return ( u ) ;

}

/*

    DECODE AN EXTERNAL NAME

    A number of bits are read and, according to their value, either a

    string or a unique is decoded.

*/

external de_extern_name

    PROTO_Z ()

{

    external e ;

    long n = de_external () ;

    byte_align () ;

    switch ( n ) {

	case external_string_extern : {

	    e.simple = 1 ;

	    e.val.str = de_tdfstring_align () ;

	    break ;

	}

	case external_unique_extern : {

	    e.simple = 0 ;

	    e.val.uniq = de_unique () ;

	    break ;

	}

	case external_chain_extern : {

	    e.simple = 1 ;

	    e.val.str = de_tdfstring_align () ;

	    IGNORE tdf_int () ;

	    break ;

	}

	default : {

	    e.simple = 1 ;

	    e.val.str = "<ERROR>" ;

	    break ;

	}

    }

    return ( e ) ;

}

/*

    ARRAY OF FOREIGN SORTS

    Foreign sorts are identified by means of strings.  This array gives all

    the foreign sorts known to the program.

*/

int do_foreign_sorts = 0 ;

long no_foreign_sorts = 0 ;

sortid *foreign_sorts = null ;

static long fs_size = 0 ;

/*

    ADD A FOREIGN SORT

    The foreign sort with name nm, foreign name fnm and decode letter c is

    added to the array of foreign sorts.

*/

void add_foreign_sort

    PROTO_N ( ( nm, fnm, c ) )

    PROTO_T ( char *nm X char *fnm X int c )

{

    long n = no_foreign_sorts++ ;

    if ( n >= fs_size ) {

	fs_size += 20 ;

	foreign_sorts = realloc_nof ( foreign_sorts, sortid, fs_size ) ;

    }

    foreign_sorts [n].name = nm ;

    foreign_sorts [n].fname = fnm ;

    foreign_sorts [n].decode = ( char ) c ;

    foreign_sorts [n].res = ( sortname ) ( extra_sorts + n ) ;

    foreign_sorts [n].args = null ;

    return ;

}

/*

    DECODE A COMPLEX SORT AS A STRING

*/

static sortid de_complex_sort

    PROTO_N ( ( sn ) )

    PROTO_T ( sortname sn )

{

    sortid cs ;

    if ( sn == sort_token ) {

	long i, n ;

	sortid cp, cr ;

	char buff [1000] ;

	char *p = buff ;

	/* Decode result of token sort */

	cr = de_sort_name ( 0 ) ;

	cs.res = cr.res ;

	cr = de_complex_sort ( cs.res ) ;

	/* Start decoding token sort */

	cs.decode = 'T' ;

	check_list () ;

	n = tdf_int () ;

	cs.args = alloc_nof ( char, n + 1 ) ;

	IGNORE strcpy ( p, "TOKEN(" ) ;

	p = p + strlen ( p ) ;

	/* Decode arguments of token sort */

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

	    cp = de_sort_name ( 0 ) ;

	    cp = de_complex_sort ( cp.res ) ;

	    if ( i ) *( p++ ) = ',' ;

	    IGNORE strcpy ( p, cp.name ) ;

	    p = p + strlen ( p ) ;

	    cs.args [i] = cp.decode ;

	}

	cs.args [n] = 0 ;

	IGNORE strcpy ( p, ")->" ) ;

	p = p + strlen ( p ) ;

	/* Copy token sort */

	IGNORE strcpy ( p, cr.name ) ;

	p = alloc_nof ( char, ( int ) strlen ( buff ) + 1 ) ;

	IGNORE strcpy ( p, buff ) ;

	cs.name = p ;

    } else {

	/* Non-token sorts are simple */

	cs = find_sort ( sn ) ;

    }

    return ( cs ) ;

}

/*

    DECODE A SORTNAME

    A value representing a sort is read and returned.  If expand is true

    then the parameters and result of any high-level sort are read but

    discarded.

*/

sortid de_sort_name

    PROTO_N ( ( expand ) )

    PROTO_T ( int expand )

{

    sortname sn = ( sortname ) de_sortname () ;

    if ( sn == sort_token && expand ) {

	return ( de_complex_sort ( sn ) ) ;

    }

    if ( sn == sort_foreign ) {

	long i ;

	string nm ;

#if string_ext

	long n = fetch_extn ( string_bits ) ;

#else

	long n = fetch ( string_bits ) ;

#endif

	if ( n != string_make_string ) {

	    input_error ( "Unknown foreign sort" ) ;

	}

	nm = de_tdfstring () ;

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

	    if ( streq ( nm, foreign_sorts [i].fname ) ) {

		return ( foreign_sorts [i] ) ;

	    }

	}

	add_foreign_sort ( nm, nm, 'F' ) ;

	return ( foreign_sorts [i] ) ;

    }

    return ( find_sort ( sn ) ) ;

}