/* 
 * Reader.h
 * Author: Hannah C. Tang (hctang@cs)
 *
 * Specification of public functions for the Reader struct
 * (the module parser)
 *
 * $Id: Reader.h,v 1.3 2001/12/18 14:48:49 cse466_t Exp $
 *
 */

#ifndef READER_H
#define READER_H

#include <stdio.h>
#include "common.h"


/* A Reader struct is basically a scanner/parser for the
 * following simple grammer:
 *
 * <program>        ::= <mode> | <main>
 * <mode>           ::= M <int> { <mode stmt list> }
 * <main>           ::= P { <main stmt list> }
 *
 * <mode seq list>  ::= <mode seq> <mode seq list> | ""
 * <mode seq>       ::= ( <int1> <int2> ... <int16> )
 *
 * <main stmt list> ::= <main stmt> <main stmt list> | ""
 * <main stmt>      ::= <loop> | <sequence>
 *
 * <loop>           ::= L <int> { <main stmt list> }
 * <sequence>       ::= ( <int> <int> <int> )
 * <int>            ::= an integer
 *
 * Comments begin at '#' and end with the line.
 *
 */


struct Reader;

enum Reader_TokenType { 
    SEQUENCE, /* Program and mode sequences are both returned as
                 SEQUENCE it's up to the user to figure out which 
                 is which, depending on previous token type */
    MODE_START,
    MODE_SEQUENCE,
    PROGRAM_START,
    PROGRAM_SEQUENCE,
    LOOP_START,
    BLOCK_END,
    END_OF_FILE 
};


/* Dynamically allocate and free Reader structs */
struct Reader* Reader_malloc( FILE *pInFile );
void Reader_free( struct Reader *pR );


/* Return the type of the next token */
enum Reader_TokenType Reader_getNextTokenType( struct Reader *pR );


/* Get the value of the user-specified mode.  Returns Bool_false
 * if not successful */
Bool Reader_getMode( struct Reader *pR, unsigned int *pNewModeNum );

/* Get the mode-sequence values as a bit-vector.  Returns Bool_false 
 * if not successful */
Bool Reader_getModeSequence( struct Reader *pR,
                             unsigned int *pModeSeq );

/* Clear out the Program-start flag.  Returns Bool_false if
 * not successful */
Bool Reader_getProgram( struct Reader *pR );

/* Get the sequence-values.  Returns Bool_false if not successful */
Bool Reader_getSequence( struct Reader *pR,
                         unsigned int *pLength,
                         unsigned int *pPeriod,
                         unsigned int *pMode );

/* Get the number of times this loop should execute */
Bool Reader_getLoop( struct Reader *pR, unsigned int *pNumLoops );

/* Clear out the loop-end flag */
Bool Reader_getBlockEnd( struct Reader *pR );


#endif /* READER_H */