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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.
*/


#define calculus_IO_ROUTINES
#include "config.h"
#include "read.h"
#include "calculus.h"
#include "common.h"
#include "error.h"
#include "write.h"


/*
    OUTPUT FILE

    These variables describe the output file.  There is a one byte output
    buffer.
*/

static FILE *output_file ;
static unsigned long output_buff = 0 ;
static int output_bits = 0 ;


/*
    WRITE A NUMBER OF BITS

    This routine writes the value v into n bits.
*/

static void write_bits
    PROTO_N ( ( n, v ) )
    PROTO_T ( int n X unsigned long v )
{
    if ( n > CHAR_BIT ) {
        write_bits ( n - CHAR_BIT, ( v >> CHAR_BIT ) ) ;
        write_bits ( CHAR_BIT, ( v & ( unsigned ) MASK ( CHAR_BIT ) ) ) ;
    } else {
        int b = output_bits + n ;
        unsigned long m = ( output_buff << n ) | v ;
        int c = b - CHAR_BIT ;
        if ( c >= 0 ) {
            /* Write next byte */
            int p = ( int ) ( m >> c ) ;
            fputc_v ( p, output_file ) ;
            m &= bitmask [c] ;
            b = c ;
        }
        output_bits = b ;
        output_buff = m ;
    }
    return ;
}


/*
    WRITE AN INTEGER

    This routine writes the integer n to the output file.  This is
    encoded as a sequence of octal digits, plus a flag to indicate the
    last digit.  The variable d is used to indicate whether this last
    digit marker should be output.  The normal method of accessing the
    routine is via the macro write_int.
*/

static void write_int_aux
    PROTO_N ( ( n, d ) )
    PROTO_T ( unsigned long n X unsigned long d )
{
    unsigned long m = ( n >> 3 ) ;
    if ( m ) write_int_aux ( m, ( unsigned long ) 0x00 ) ;
    write_bits ( 4, ( ( n & 0x07 ) | d ) ) ;
    return ;
}

#define write_int( N )  write_int_aux ( ( N ), ( unsigned long ) 0x08 )


/*
    WRITE A STRING

    This routine writes the string s to the output file.  This is
    encoded as the string length followed by the component characters
    (8 bits each).
*/

static void write_string
    PROTO_N ( ( s ) )
    PROTO_T ( char *s )
{
    unsigned long i, n = ( unsigned long ) strlen ( s ) ;
    write_int ( n ) ;
    for ( i = 0 ; i < n ; i++ ) {
        write_bits ( 8, ( unsigned long ) s [i] ) ;
    }
    return ;
}


/*
    LAST FILE NAME WRITTEN

    This variable is used to store the last file name written.
*/

static char *last_filename = NULL ;


/*
    WRITE A FILE NAME

    This routine writes the file name s.  This is just a simple string,
    but file names are buffered using last_filename.
*/

static void write_filename
    PROTO_N ( ( s ) )
    PROTO_T ( char *s )
{
    char *t = last_filename ;
    if ( t && streq ( t, s ) ) {
        write_bits ( 1, ( unsigned long ) 1 ) ;
    } else {
        write_bits ( 1, ( unsigned long ) 0 ) ;
        write_string ( s ) ;
        last_filename = s ;
    }
    return ;
}


/*
    AUTOMATICALLY GENERATED DISK WRITING ROUTINES

    The main disk writing routines are automatically generated.  The
    various macros are used to customise these routines.
*/

#define WRITE_BITS( A, B )      write_bits ( ( A ), ( unsigned long ) ( B ) )
#define WRITE_ALIAS( A )        write_int ( ( unsigned long ) ( A ) )
#define WRITE_DIM( A )          write_int ( ( unsigned long ) ( A ) )
#define WRITE_int( A )          write_int ( ( unsigned long ) ( A ) )
#define WRITE_number( A )       write_int ( ( unsigned long ) ( A ) )
#define WRITE_string( A )       write_string ( A )
#define WRITE_name_string( A )  write_filename ( A )
#define WRITE_zero_int( A )     UNUSED ( A )
#define crt_disk_alias          crt_calculus_alias

#include "write_def.h"


/*
    WRITE A FILE

    This routine writes the current algebra to disk into the file nm.
*/

void write_file
    PROTO_N ( ( nm ) )
    PROTO_T ( char *nm )
{
    /* Open file */
    if ( streq ( nm, "." ) ) {
        error ( ERROR_SERIOUS, "Output file not specified" ) ;
        return ;
    }
    output_file = fopen ( nm, "wb" ) ;
    if ( output_file == NULL ) {
        error ( ERROR_SERIOUS, "Can't open output file, '%s'", nm ) ;
        return ;
    }
    init_bitmask () ;
    output_buff = 0 ;
    output_bits = 0 ;
    last_filename = NULL ;

    /* Write the file header */
    WRITE_string ( calculus_NAME ) ;
    WRITE_string ( calculus_VERSION ) ;

    /* Write the algebra */
    WRITE_string ( algebra->name ) ;
    WRITE_int ( algebra->major_no ) ;
    WRITE_int ( algebra->minor_no ) ;
    WRITE_list_ptr_type ( algebra->types ) ;

    /* Close file */
    if ( output_bits ) {
        /* Tidy up any odd bits */
        write_bits ( CHAR_BIT - output_bits, ( unsigned long ) 0 ) ;
    }
    clear_calculus_alias () ;
    fclose_v ( output_file ) ;
    return ;
}