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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 "output.h"
#include "xalloc.h"
/*
BITMASKS
This array gives the masks for each bit value.
*/
unsigned long bitmask [ CHAR_BIT ] ;
/*
INITIALISE MASKS
This routine initialises the array of bitmasks. This is done
dynamically rather than statically in case CHAR_BIT is not 8.
*/
void init_bitmask
PROTO_Z ()
{
int i ;
for ( i = 0 ; i < CHAR_BIT ; i++ ) bitmask [i] = MASK ( i ) ;
return ;
}
/*
INPUT FILE
These variables describe the input file. There is a one byte input
buffer.
*/
static FILE *input_file ;
static unsigned long input_buff = 0 ;
static int input_bits = 0 ;
/*
READ A NUMBER OF BITS
This routine reads the next n bits from the input file.
*/
static unsigned long read_bits
PROTO_N ( ( n ) )
PROTO_T ( int n )
{
int b = input_bits ;
unsigned long m = input_buff ;
unsigned long r = 0 ;
while ( n ) {
if ( b == 0 ) {
/* Read next byte */
int c = getc ( input_file ) ;
if ( c == EOF ) {
error ( ERROR_FATAL, "Premature end of file" ) ;
} else {
m = ( ( ( unsigned long ) c ) & MASK ( CHAR_BIT ) ) ;
}
b = CHAR_BIT ;
}
if ( n >= b ) {
r = ( r << b ) | m ;
n -= b ;
b = 0 ;
} else {
int c = b - n ;
r = ( r << n ) | ( m >> c ) ;
m &= bitmask [c] ;
n = 0 ;
b = c ;
}
}
input_bits = b ;
input_buff = m ;
return ( r ) ;
}
/*
READ AN INTEGER
This routine reads an integer from the input file. This is encoded
as a sequence of octal digits with a marker bit for the end of the
number.
*/
static unsigned long read_int
PROTO_Z ()
{
unsigned long r = 0, d ;
while ( d = read_bits ( 4 ), ( d & 0x08 ) == 0 ) {
r = ( r << 3 ) | d ;
}
r = ( r << 3 ) | ( d & 0x07 ) ;
return ( r ) ;
}
/*
READ A STRING
This routine reads an integer from the input file. This is encoded
as the string length followed by the characters comprising the
string (8 bits each).
*/
static char *read_string
PROTO_Z ()
{
unsigned long i, n = read_int () ;
char *s = xstr ( ( long ) ( n + 1 ) ) ;
for ( i = 0 ; i < n ; i++ ) {
s [i] = ( char ) read_bits ( 8 ) ;
}
s [n] = 0 ;
return ( s ) ;
}
/*
READ A FILENAME
File names are just strings, however they are buffered to save
space.
*/
static char *read_filename
PROTO_Z ()
{
char *s ;
static char *last_filename = "????" ;
if ( read_bits ( 1 ) ) {
s = last_filename ;
} else {
s = read_string () ;
last_filename = s ;
}
return ( s ) ;
}
/*
AUTOMATICALLY GENERATED DISK READING ROUTINES
The main disk reading routines are automatically generated. The
various macros are used to customise these routines.
*/
#define READ_BITS( N ) ( ( unsigned ) read_bits ( N ) )
#define READ_ALIAS() ( ( unsigned ) read_int () )
#define READ_DIM() ( ( unsigned ) read_int () )
#define READ_int() ( ( int ) read_int () )
#define READ_number() ( ( number ) read_int () )
#define READ_string() read_string ()
#define READ_name_string() read_filename ()
#define READ_zero_int() 0
#include "read_def.h"
/*
READ AN INPUT FILE
This routine reads an algebra from the input file nm.
*/
void read_file
PROTO_N ( ( nm ) )
PROTO_T ( char *nm )
{
char *s ;
/* Open file */
crt_line_no = -1 ;
crt_file_name = nm ;
input_file = fopen ( nm, "rb" ) ;
if ( input_file == NULL ) {
error ( ERROR_SERIOUS, "Can't open input file, '%s'", nm ) ;
return ;
}
init_bitmask () ;
input_buff = 0 ;
input_bits = 0 ;
/* Confirm file header */
s = READ_string () ;
if ( !streq ( s, calculus_NAME ) ) {
error ( ERROR_FATAL, "Invalid file header identifier" ) ;
}
s = READ_string () ;
if ( !streq ( s, calculus_VERSION ) ) {
error ( ERROR_FATAL, "Invalid file header version, '%s'", s ) ;
}
/* Read the algebra */
algebra->name = READ_string () ;
algebra->major_no = READ_int () ;
algebra->minor_no = READ_int () ;
algebra->types = READ_list_ptr_type () ;
clear_calculus_alias () ;
/* Extract lists of primitives etc */
LOOP_TYPE {
TYPE_P t = CRT_TYPE ;
TYPE t0 = DEREF_type ( t ) ;
switch ( TAG_type ( t0 ) ) {
case type_primitive_tag : {
PRIMITIVE_P p = DEREF_ptr ( type_primitive_prim ( t0 ) ) ;
CONS_ptr ( p, algebra->primitives, algebra->primitives ) ;
break ;
}
case type_ident_tag : {
IDENTITY_P p = DEREF_ptr ( type_ident_id ( t0 ) ) ;
CONS_ptr ( p, algebra->identities, algebra->identities ) ;
break ;
}
case type_enumeration_tag : {
ENUM_P p = DEREF_ptr ( type_enumeration_en ( t0 ) ) ;
CONS_ptr ( p, algebra->enumerations, algebra->enumerations ) ;
break ;
}
case type_structure_tag : {
STRUCTURE_P p = DEREF_ptr ( type_structure_struc ( t0 ) ) ;
CONS_ptr ( p, algebra->structures, algebra->structures ) ;
break ;
}
case type_onion_tag : {
UNION_P p = DEREF_ptr ( type_onion_un ( t0 ) ) ;
CONS_ptr ( p, algebra->unions, algebra->unions ) ;
break ;
}
}
}
/* Close file */
fclose_v ( input_file ) ;
return ;
}