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1992-05-26
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102 lines
// LISTING 5. DFA.H
// Definitions and structs for DFA_CLASS object
// User-defined constants here;
// these are the defaults */
#define LBR '{'
#define RBR '}'
#define GS ':'
#define FS '\\'
#define EOR '\n'
#define TAB '\t'
#define DOT '.'
#define WSPACE ' '
#define MAXBUFLEN 512
// Control modes for file operations
#define READ_TEXT "rt"
#define READ_BINARY "rb"
#define WRITE_TEXT "wt"
#define WRITE_BINARY "wb"
// DFA-specific constants are here,
// and following. Dangerous to edit these.
#define GOOD 1
#define BAD 0
#define ERR -1
#define OK 0
#define OUT 99
#define YES 1
#define NO 0
#define EMPTY ((char) '\0')
// Definition of state table
// (a data table to the state machine)
typedef struct dfa {
short (*target)(char *); // validate token fcn
short good; // passed dest state
short bad; // failed dest state
short (*goodfcn)(char *); // target passed
short (*badfcn)(char *); // target failed
} DFATBL;
// Definition of the state machinery:
typedef struct object {
// public-overidable elements
DFATBL *tbl; // ptr to the state table
FILE *infile; // input file to be parsed
char *(*get_token)(struct object *); // tokenizer
char *delim; // ptr to string of delimiters
// Internal working variables
short (*movest)(struct object *, short);
short ndx; // current index (substate)
short oflag; // general work flag
char *wp; // ptr into workbuf
int cp; // character holding area
char workbuf[MAXBUFLEN];// working area
} DFA_CLASS;
extern DFA_CLASS *o;
extern short need_token;
extern short linenbr;
extern short StateMachine(DFA_CLASS *);
extern void InitStateMachine(DFA_CLASS *,
void *, char *, FILE *, char *);
// declarations for DFA_CLASS functions */
extern short block(char *);
extern short errmsg(char *);
extern char *get_token(DFA_CLASS *);
extern short isEOF(char *);
extern short isFS(char *);
extern short isGS(char *);
extern short isLBR(char *);
extern short isRBR(char *);
extern short move(DFA_CLASS *, short);
extern void mystrtok(char *, char *, char *);
extern short skip(char *);
#define IGNORE(x) (x); // for portability
#define CURRENT_STATE (o->ndx)
#define STATE_TBL o->tbl
#define GOODSTATE (STATE_TBL[CURRENT_STATE].good)
#define BADSTATE (STATE_TBL[CURRENT_STATE].bad)
#define GOODFCN(x) \
((*(STATE_TBL[CURRENT_STATE].goodfcn))(x))
#define BADFCN(x) \
((*(STATE_TBL[CURRENT_STATE].badfcn))(x))
#define TARGET(x) \
((*(STATE_TBL[CURRENT_STATE].target))(x))
#define NEXT_STATE(x) ((*o->movest)(o,x))
#define GET_TOKEN ((*o->get_token)(o))
#define INFILE (o->infile)
// Useful Macros
#define PTRSUB(p,x) ((long) p - (long) x)
#define PTRADD(p,x) ((long) p + (long) x)
#define LASTBYTE(x) (x[strlen(x)-1])
#define DIMEN(x) (sizeof(x)/sizeof(x[0]))