minix/commands/yap/machine.h
2009-11-09 10:26:00 +00:00

60 lines
1.7 KiB
C

/* Copyright (c) 1985 Ceriel J.H. Jacobs */
/* $Header$ */
# ifndef _MACHINE_
# define PUBLIC extern
# else
# define PUBLIC
# endif
/*
* Simple minded finite state machine implementation to recognize
* strings.
*/
struct state {
char s_char; /* character to match with */
char s_endstate; /* flag, 1 if this state is an endstate */
struct state *s_match; /* new state if matched */
struct state *s_next; /* other characters to match with */
short s_cnt; /* if an endstate, this field is filled with
* some info, dependant on the machine.
*/
};
# define FSM_OKE 0
# define FSM_ISPREFIX -1 /* Must be < 0 */
# define FSM_HASPREFIX 1
int addstring();
/*
* int addstring(str,cnt,mach)
* char *str; The string to be recognized
* int cnt; Attribute of the string.
* struct state **mach; The finite state machine
*
* This routine adds a string to a finite state automaton.
* It returns FSM_ISPREFIX if the added string is a prefix of a string already
* in the automaton, FSM_HASPREFIX if a string, already recognized by the
* automaton, is a prefix of the added string.
* Otherwise it returns FSM_OKE.
*/
int match();
/*
* int match(str,p_int,mach)
* char *str; pointer to string
* int *p_int; Pointer to an integer
* struct state *mach; The finite state machine
*
* A match of the string indicated by "str" is tried. If a head of "str"
* is recognized by the finite state automaton, a machine dependant number
* is put in the integer pointed to by "p_int".
* The number of characters that match is returned, so a return value of 0
* means no match.
* A return value of FSM_PREFIX means that the string "str" was a prefix of a
* matched string.
*/
# undef PUBLIC