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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 "calculus.h"

#include "error.h"

#include "lex.h"

#include "syntax.h"

#include "xalloc.h"

/*

    INPUT FLAGS

    The flag new_format is set to true to indicate the new input format.

    The flags allow_stack and allow_vec are set to false to suppress the

    stack and vector operations respectively.

*/

int new_format = 1 ;

int allow_stack = 1 ;

int allow_vec = 1 ;

/*

    CHECK STACK FLAG

    This routine is called if the STACK keyword is encountered to check the

    value of allow_stack.

*/

static int check_stack

    PROTO_N ( ( t ) )

    PROTO_T ( int t )

{

    if ( !allow_stack ) {

	error ( ERROR_SERIOUS, "Stack operations have been suppressed" ) ;

	allow_stack = 1 ;

    }

    return ( t ) ;

}

/*

    CHECK VECTOR FLAG

    This routine is called if the VEC or VEC_PTR keywords are encountered

    to check the value of allow_vec.

*/

static int check_vec

    PROTO_N ( ( t ) )

    PROTO_T ( int t )

{

    if ( !allow_vec ) {

	error ( ERROR_SERIOUS, "Vector operations have been suppressed" ) ;

	allow_vec = 1 ;

    }

    return ( t ) ;

}

/*

    INPUT FILE

    This is the file from which the lexical routine read their input.

*/

static FILE *lex_input ;

/*

    PENDING BUFFER

    Pending characters are dealt with by means of this buffer.  pending

    is set to the start of the buffer to indicate that there are no

    characters pending, otherwise the pending characters are stored in

    the buffer.  The buffer may need increasing in size if the look-ahead

    required by the lexical analyser increases.

*/

static int pending_buff [12] = { '?' } ;

static int *pending = pending_buff ;

/*

    MAPPINGS AND DECLARATIONS FOR AUTOMATICALLY GENERATED SECTION

    These macros give the mappings between the actions used in the

    automatically generated lexical analyser and the routines defined

    in this file.

*/

static int read_char PROTO_S ( ( void ) ) ;

static int read_comment PROTO_S ( ( void ) ) ;

static int read_hex PROTO_S ( ( int ) ) ;

static int read_identifier PROTO_S ( ( int ) ) ;

static int read_number PROTO_S ( ( int ) ) ;

static int read_string PROTO_S ( ( void ) ) ;

#define get_comment( A, B )	read_comment ()

#define get_hex( A, B, C )	read_hex ( C )

#define get_identifier( A )	read_identifier ( A )

#define get_number( A )		read_number ( A )

#define get_string( A )		read_string ()

#define get_stack()		check_stack ( lex_stack )

#define get_vec()		check_vec ( lex_vec )

#define get_vec_ptr()		check_vec ( lex_vec_Hptr )

#define unknown_token( A )	lex_unknown

#define unread_char( A )	*( ++pending ) = ( A )

/*

    AUTOMATICALLY GENERATED SECTION

    The main body of the lexical analyser is automatically generated.

*/

#include "lexer.h"

/*

    GET THE NEXT CHARACTER

    This routine reads the next character, either from the pending buffer

    or from the input file.

*/

static int read_char

    PROTO_Z ()

{

    int c ;

    if ( pending != pending_buff ) {

	c = *( pending-- ) ;

    } else {

	c = fgetc ( lex_input ) ;

	if ( c == '\n' ) crt_line_no++ ;

	if ( c == EOF ) return ( LEX_EOF ) ;

	c &= 0xff ;

    }

    return ( c ) ;

}

/*

    TOKEN BUFFER

    This buffer is used by read_token to hold the values of identifiers

    and strings.  The variable token_value is also used to hold the

    values of numbers.

*/

char token_buff [2000] ;

static char *token_end = token_buff + sizeof ( token_buff ) ;

char *first_comment = NULL ;

number token_value ;

/*

    READ AN IDENTIFIER

    This routine reads an identifier beginning with a, returning the

    corresponding lexical token.  Keywords are dealt with locally.

*/

static int read_identifier

    PROTO_N ( ( a ) )

    PROTO_T ( int a )

{

    int c = a, cl ;

    char *t = token_buff ;

    do {

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

	if ( t == token_end ) error ( ERROR_FATAL, "Buffer overflow" ) ;

	c = read_char () ;

	cl = lookup_char ( c ) ;

    } while ( is_alphanum ( cl ) ) ;

    *t = 0 ;

    unread_char ( c ) ;

    /* Check for keywords */

    t = token_buff ;

#define MAKE_KEYWORD( A, B )\

    if ( streq ( t, ( A ) ) ) return ( B ) ;

#include "keyword.h"

    return ( lex_identifier ) ;

}

/*

    READ A NUMBER

    This routine reads a number beginning with a, returning the

    corresponding lexical token.  The actual value of the number is built

    up in token_value.

*/

static int read_number

    PROTO_N ( ( a ) )

    PROTO_T ( int a )

{

    int c = a, cl ;

    number n = 0 ;

    do {

	n = 10 * n + ( number ) ( c - '0' ) ;

	c = read_char () ;

	cl = lookup_char ( c ) ;

    } while ( is_digit ( cl ) ) ;

    unread_char ( c ) ;

    token_value = n ;

    return ( lex_number ) ;

}

/*

    READ A HEXADECIMAL NUMBER

    This routine reads a hexadecimal number beginning with a, returning the

    corresponding lexical token.  The actual value of the number is built

    up in token_value.

*/

static int read_hex

    PROTO_N ( ( a ) )

    PROTO_T ( int a )

{

    int c = a, cl ;

    number n = 0 ;

    do {

	number d ;

	if ( c >= '0' && c <= '9' ) {

	    d = ( number  ) ( c - '0' ) ;

	} else if ( c >= 'A' && c <= 'Z' ) {

	    d = ( number ) ( c - 'A' ) + 10 ;

	} else {

	    d = ( number ) ( c - 'a' ) + 10 ;

	}

	n = 16 * n + d ;

	c = read_char () ;

	cl = lookup_char ( c ) ;

    } while ( is_hexdigit ( cl ) ) ;

    unread_char ( c ) ;

    token_value = n ;

    return ( lex_number ) ;

}

/*

    READ A STRING

    This routine reads a string.  It is entered after the initial

    quote has been read.  Note that there are no escape sequences.

*/

static int read_string

    PROTO_Z ()

{

    int c ;

    char *t = token_buff ;

    while ( c = read_char (), c != '"' ) {

	if ( c == '\n' || c == LEX_EOF ) {

	    error ( ERROR_SERIOUS, "Unexpected end of string" ) ;

	    break ;

	}

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

	if ( t == token_end ) error ( ERROR_FATAL, "Buffer overflow" ) ;

    }

    *t = 0 ;

    return ( lex_string ) ;

}

/*

    READ A COMMENT

    This routine reads a C style comment, returning the lexical token

    immediately following.  It is entered after the first two characters

    have been read.

*/

static int read_comment

    PROTO_Z ()

{

    int state = 0 ;

    char *t = token_buff ;

    *( t++ ) = '/' ;

    *( t++ ) = '*' ;

    while ( state != 2 ) {

	int c = read_char () ;

	if ( c == LEX_EOF ) {

	    error ( ERROR_SERIOUS, "End of file in comment" ) ;

	    return ( lex_eof ) ;

	}

	if ( c == '*' ) {

	    state = 1 ;

	} else if ( state == 1 && c == '/' ) {

	    state = 2 ;

	} else {

	    state = 0 ;

	}

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

	if ( t == token_end ) t = token_buff + 2 ;

    }

    *t = 0 ;

    if ( first_comment == NULL ) first_comment = xstrcpy ( token_buff ) ;

    return ( read_token () ) ;

}

/*

    CURRENT TOKEN

    These variables are used by the parser to hold the current and former

    lexical tokens.

*/

int crt_lex_token ;

int saved_lex_token ;

/*

    PROCESS FILE

    This routine processes the input file nm.  If r is true then it is

    processed using read_calculus, otherwise extra_calculus is used.

*/

void process_file

    PROTO_N ( ( nm, r ) )

    PROTO_T ( char *nm X int r )

{

    crt_line_no = 1 ;

    crt_file_name = nm ;

    lex_input = fopen ( nm, "r" ) ;

    if ( lex_input == NULL ) {

	error ( ERROR_SERIOUS, "Can't open input file, '%s'", nm ) ;

	return ;

    }

    ADVANCE_LEXER ;

    if ( r ) {

	read_calculus () ;

    } else {

	extra_calculus () ;

    }

    if ( crt_lex_token != lex_eof ) {

	error ( ERROR_SERIOUS, "Terminating due to syntax error" ) ;

    }

    fclose_v ( lex_input ) ;

    return ;

}