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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 "util.h"

#include "defs.h"

#include "streams.h"

#include "enc_nos.h"

#include "errors.h"

TDF * current_TDF;

static Chunk * free_chunks = (Chunk*)0;

Chunk * create_chunk

    PROTO_Z ()

{

    Chunk * ans;

    if (free_chunks != (Chunk*)0) {

	ans = free_chunks;

	free_chunks = free_chunks->next;

    } else {

	ans = MALLOC(Chunk);

    }

    ans->next = (Chunk*)0;

    ans->usage = 0;

    ans->offst = 0;  ans->aligned = 0;

    ans->data[0] = 0;

    return ans;

}

static void free_chunk

    PROTO_N ( (x) )

    PROTO_T ( Chunk * x )

{

    x->next = free_chunks;

    free_chunks = x;

}

void out_basic_int

    PROTO_N ( (num, bts) )

    PROTO_T ( unsigned long num X unsigned int bts )

    /* outputs num onto current stream in bts bits */

{

    Chunk * t_ch = current_TDF->last;

    unsigned disp = t_ch->offst;

    unsigned space = 8 - disp;

    for(;bts>=space;bts-=space,space=8,disp=0){

	(t_ch->data)[t_ch->usage]|=UC((num>>(bts-space))&255);

	t_ch->usage+=1;t_ch->offst=0;

	if(t_ch->usage == DATA_SIZE) {

	    Chunk * nch = create_chunk();

	    t_ch->next = nch;

	    current_TDF->last = nch;

	    t_ch = nch;

	}

	else (t_ch->data)[t_ch->usage] = 0;

    }

    if(bts){

	unsigned garbage=8-bts;

	(t_ch->data)[t_ch->usage]|=UC(((num<<garbage)&255)>>disp);

	t_ch->offst+=UC(bts);

    }

}

void append_TDF

    PROTO_N ( (tdf, free_it) )

    PROTO_T ( TDF * tdf X Bool free_it )

    /* appends the stream tdf onto current stream;

       if free_it, chunks in tdf will be reused */

{

    Chunk * t_ch = current_TDF->last;

    Chunk * a_ch = tdf->first;

    if (t_ch->usage < DATA_SIZE -1 - a_ch->usage ) {

	/* room to put it in current chunk */

	int i;

	int offst = a_ch->offst;

	Chunk * nextch = a_ch->next;

	for(i=0; i<a_ch->usage; i++) {

	    out_basic_int(UL(a_ch->data[i]),UI(8));

	}

	if (a_ch ->offst != 0) {

	    out_basic_int(UL(a_ch->data[i])>>(8-offst), UI(offst));

	}

	if (free_it) free_chunk(a_ch);

	a_ch = nextch;

    }

    if (a_ch != (Chunk*)0) {

	if (free_it) {	/* use existing chunks */

	    t_ch->next = a_ch;

	    current_TDF->last = tdf->last;

	} else {  /* copy chunks */

	    while( a_ch != (Chunk*)0 ) {

		Chunk *nch = create_chunk();

		t_ch->next = nch;

		t_ch = current_TDF->last = nch;

		*nch = *a_ch;

		a_ch = a_ch->next;

	    }

	}

    }

    SET_RSORT(tdf->sort);

    if (free_it) {

	tdf->first = tdf->last = (Chunk*)0; /* Don't use it again! */

    }

    return;

}

unsigned long bits_in_TDF

    PROTO_N ( (tdf) )

    PROTO_T ( TDF * tdf )

{

    Chunk * t_ch = tdf->first;

    unsigned long ans = 0;

    while (t_ch != (Chunk*)0) {

	Assert(!t_ch->aligned);

	ans+= (UL(t_ch->usage)<<3) + UL(t_ch->offst);

	t_ch = t_ch->next;

    }

    return ans;

}

void out_extendable_int

    PROTO_N ( (num, bts) )

    PROTO_T ( unsigned long num X unsigned int bts )

{

    if (num < (UL(1)<<bts)) {

	out_basic_int(num,bts);

    } else {

	out_basic_int(UL(0), bts);

	out_extendable_int(num-(UL(1)<<bts)+1, bts);

    }

}

void out_tdfint32

    PROTO_N ( (n) )

    PROTO_T ( unsigned long n )

    /* output 32 bit int as tdfint */

{

    int sh;

    Bool sig = 0;

    for (sh=30; sh>0; sh-=3) {

	unsigned long i = (n>>sh)&7;

	if (sig || i!=0) {

	    out_basic_int(i, UI(4));

	    sig = 1;

	}

    }

    out_basic_int((n &7)+8, 4);

    SET_RSORT(s_tdfint);

}

void out_tdfbool

    PROTO_N ( (b) )

    PROTO_T ( Bool b )

{

    out_basic_int(UL(b), UI(1));

    SET_RSORT(s_tdfbool);

}

void out_tdfstring_bytes

    PROTO_N ( (s, k, n) )

    PROTO_T ( char * s X unsigned int k X unsigned int n )

{

    unsigned int i;

    out_tdfint32(UL(k));

    out_tdfint32(UL(n));

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

	out_basic_int(UL(s[i]), k);

    }

    SET_RSORT(s_tdfstring);

}

void byte_align

    PROTO_Z ()

{

    Chunk * ch = current_TDF->last;

    if (ch->aligned !=0) {

      if (ch->offst !=0) out_basic_int(UL(0), UI(8-ch->offst));

      Assert(ch->offst == 0);

    } else {

       Chunk * nch = create_chunk();

       nch->aligned = 1;

       ch->next = nch;

       current_TDF->last = nch;

    }

}

void out_tdfident_bytes

    PROTO_N ( (s) )

    PROTO_T ( char *s )

{

    unsigned long i;

    unsigned long n = (unsigned long) strlen(s);

    byte_align();

    out_tdfint32(UL(8));

    out_tdfint32(n);

    byte_align();

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

	out_basic_int(UL(s[i]), UI(8));

    }

    SET_RSORT(s_tdfident);

}

void append_bytestream

    PROTO_N ( (tdf, free_it) )

    PROTO_T ( TDF * tdf X Bool free_it )

{

    unsigned long len = bits_in_TDF(tdf);

    unsigned long lenb = (len+7)>>3;

    out_tdfint32(lenb);

    byte_align();

    append_TDF(tdf, free_it);

    if ((lenb<<3) != len ) {

	out_basic_int(UL(0), UI((lenb<<3)-len));

    }

    SET_RSORT(s_bytestream);

}