regcomp.h

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

/*
 *  substitution list
 */
#define NSUBEXP 32
typedef struct Resublist	Resublist;
struct	Resublist
{
	Resub	m[NSUBEXP];
};

/* max character classes per program */
Reprog	RePrOg;
#define	NCLASS	(sizeof(RePrOg.class)/sizeof(Reclass))

/* max rune ranges per character class */
#define NCCRUNE	(sizeof(Reclass)/sizeof(Rune))

/*
 * Actions and Tokens (Reinst types)
 *
 *	02xx are operators, value == precedence
 *	03xx are tokens, i.e. operands for operators
 */
#define RUNE		0177
#define	OPERATOR	0200	/* Bitmask of all operators */
#define	START		0200	/* Start, used for marker on stack */
#define	RBRA		0201	/* Right bracket, ) */
#define	LBRA		0202	/* Left bracket, ( */
#define	OR		0203	/* Alternation, | */
#define	CAT		0204	/* Concatentation, implicit operator */
#define	STAR		0205	/* Closure, * */
#define	PLUS		0206	/* a+ == aa* */
#define	QUEST		0207	/* a? == a|nothing, i.e. 0 or 1 a's */
#define	ANY		0300	/* Any character except newline, . */
#define	ANYNL		0301	/* Any character including newline, . */
#define	NOP		0302	/* No operation, internal use only */
#define	BOL		0303	/* Beginning of line, ^ */
#define	EOL		0304	/* End of line, $ */
#define	CCLASS		0305	/* Character class, [] */
#define	NCCLASS		0306	/* Negated character class, [] */
#define	END		0377	/* Terminate: match found */

/*
 *  regexec execution lists
 */
#define LISTSIZE	10
#define BIGLISTSIZE	(25*LISTSIZE)
typedef struct Relist	Relist;
struct Relist
{
	Reinst*		inst;		/* Reinstruction of the thread */
	Resublist	se;		/* matched subexpressions in this thread */
};
typedef struct Reljunk	Reljunk;
struct	Reljunk
{
	Relist*	relist[2];
	Relist*	reliste[2];
	int	starttype;
	Rune	startchar;
	char*	starts;
	char*	eol;
	Rune*	rstarts;
	Rune*	reol;
};

extern Relist*	_renewthread(Relist*, Reinst*, int, Resublist*);
extern void	_renewmatch(Resub*, int, Resublist*);
extern Relist*	_renewemptythread(Relist*, Reinst*, int, char*);
extern Relist*	_rrenewemptythread(Relist*, Reinst*, int, Rune*);