[perl5.git] / regcomp.h

/*    regcomp.h
 */

/*
 * The "internal use only" fields in regexp.h are present to pass info from
 * compile to execute that permits the execute phase to run lots faster on
 * simple cases.  They are:
 *
 * regstart	sv that must begin a match; Nullch if none obvious
 * reganch	is the match anchored (at beginning-of-line only)?
 * regmust	string (pointer into program) that match must include, or NULL
 *  [regmust changed to SV* for bminstr()--law]
 * regmlen	length of regmust string
 *  [regmlen not used currently]
 *
 * Regstart and reganch permit very fast decisions on suitable starting points
 * for a match, cutting down the work a lot.  Regmust permits fast rejection
 * of lines that cannot possibly match.  The regmust tests are costly enough
 * that pregcomp() supplies a regmust only if the r.e. contains something
 * potentially expensive (at present, the only such thing detected is * or +
 * at the start of the r.e., which can involve a lot of backup).  Regmlen is
 * supplied because the test in pregexec() needs it and pregcomp() is computing
 * it anyway.
 * [regmust is now supplied always.  The tests that use regmust have a
 * heuristic that disables the test if it usually matches.]
 *
 * [In fact, we now use regmust in many cases to locate where the search
 * starts in the string, so if regback is >= 0, the regmust search is never
 * wasted effort.  The regback variable says how many characters back from
 * where regmust matched is the earliest possible start of the match.
 * For instance, /[a-z].foo/ has a regmust of 'foo' and a regback of 2.]
 */

/*
 * Structure for regexp "program".  This is essentially a linear encoding
 * of a nondeterministic finite-state machine (aka syntax charts or
 * "railroad normal form" in parsing technology).  Each node is an opcode
 * plus a "next" pointer, possibly plus an operand.  "Next" pointers of
 * all nodes except BRANCH implement concatenation; a "next" pointer with
 * a BRANCH on both ends of it is connecting two alternatives.  (Here we
 * have one of the subtle syntax dependencies:  an individual BRANCH (as
 * opposed to a collection of them) is never concatenated with anything
 * because of operator precedence.)  The operand of some types of node is
 * a literal string; for others, it is a node leading into a sub-FSM.  In
 * particular, the operand of a BRANCH node is the first node of the branch.
 * (NB this is *not* a tree structure:  the tail of the branch connects
 * to the thing following the set of BRANCHes.)  The opcodes are:
 */

/* definition	number	opnd?	meaning */
#define	END	 0	/* no	End of program. */
#define	BOL	 1	/* no	Match "" at beginning of line. */
#define MBOL	 2	/* no	Same, assuming multiline. */
#define SBOL	 3	/* no	Same, assuming singleline. */
#define	EOL	 4	/* no	Match "" at end of line. */
#define MEOL	 5	/* no	Same, assuming multiline. */
#define SEOL	 6	/* no	Same, assuming singleline. */
#define	ANY	 7	/* no	Match any one character (except newline). */
#define	SANY	 8	/* no	Match any one character. */
#define	ANYOF	 9	/* sv	Match character in (or not in) this class. */
#define	CURLY	10	/* sv	Match this simple thing {n,m} times. */
#define	CURLYX	11	/* sv	Match this complex thing {n,m} times. */
#define	BRANCH	12	/* node	Match this alternative, or the next... */
#define	BACK	13	/* no	Match "", "next" ptr points backward. */
#define	EXACT	14	/* sv	Match this string (preceded by length). */
#define	EXACTF	15	/* sv	Match this string, folded (prec. by length). */
#define	EXACTFL	16	/* sv	Match this string, folded in locale (w/len). */
#define	NOTHING	17	/* no	Match empty string. */
#define	STAR	18	/* node	Match this (simple) thing 0 or more times. */
#define	PLUS	19	/* node	Match this (simple) thing 1 or more times. */
#define BOUND	20	/* no	Match "" at any word boundary */
#define BOUNDL	21	/* no	Match "" at any word boundary */
#define NBOUND	22	/* no	Match "" at any word non-boundary */
#define NBOUNDL	23	/* no	Match "" at any word non-boundary */
#define REF	24	/* num	Match already matched string */
#define REFF	25	/* num	Match already matched string, folded */
#define REFFL	26	/* num	Match already matched string, folded in loc. */
#define	OPEN	27	/* num	Mark this point in input as start of #n. */
#define	CLOSE	28	/* num	Analogous to OPEN. */
#define MINMOD	29	/* no	Next operator is not greedy. */
#define GPOS	30	/* no	Matches where last m//g left off. */
#define IFMATCH	31	/* no	Succeeds if the following matches. */
#define UNLESSM	32	/* no	Fails if the following matches. */
#define SUCCEED	33	/* no	Return from a subroutine, basically. */
#define WHILEM	34	/* no	Do curly processing and see if rest matches. */
#define ALNUM	35	/* no	Match any alphanumeric character */
#define ALNUML	36 	/* no	Match any alphanumeric char in locale */
#define NALNUM	37	/* no	Match any non-alphanumeric character */
#define NALNUML	38	/* no	Match any non-alphanumeric char in locale */
#define SPACE	39	/* no	Match any whitespace character */
#define SPACEL	40	/* no	Match any whitespace char in locale */
#define NSPACE	41	/* no	Match any non-whitespace character */
#define NSPACEL	42	/* no	Match any non-whitespace char in locale */
#define DIGIT	43	/* no	Match any numeric character */
#define NDIGIT	44	/* no	Match any non-numeric character */

/*
 * Opcode notes:
 *
 * BRANCH	The set of branches constituting a single choice are hooked
 *		together with their "next" pointers, since precedence prevents
 *		anything being concatenated to any individual branch.  The
 *		"next" pointer of the last BRANCH in a choice points to the
 *		thing following the whole choice.  This is also where the
 *		final "next" pointer of each individual branch points; each
 *		branch starts with the operand node of a BRANCH node.
 *
 * BACK		Normal "next" pointers all implicitly point forward; BACK
 *		exists to make loop structures possible.
 *
 * STAR,PLUS	'?', and complex '*' and '+', are implemented as circular
 *		BRANCH structures using BACK.  Simple cases (one character
 *		per match) are implemented with STAR and PLUS for speed
 *		and to minimize recursive plunges.
 *
 * OPEN,CLOSE	...are numbered at compile time.
 */

#ifndef DOINIT
EXT char regarglen[];
#else
EXT char regarglen[] = {
    0,0,0,0,0,0,0,0,0,0,
    /*CURLY*/ 4, /*CURLYX*/ 4,
    0,0,0,0,0,0,0,0,0,0,0,0,
    /*REF*/ 2, 2, 2, /*OPEN*/ 2, /*CLOSE*/ 2,
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
};
#endif

#ifndef DOINIT
EXT char regkind[];
#else
EXT char regkind[] = {
	END,
	BOL,
	BOL,
	BOL,
	EOL,
	EOL,
	EOL,
	ANY,
	ANY,
	ANYOF,
	CURLY,
	CURLY,
	BRANCH,
	BACK,
	EXACT,
	EXACT,
	EXACT,
	NOTHING,
	STAR,
	PLUS,
	BOUND,
	BOUND,
	NBOUND,
	NBOUND,
	REF,
	REF,
	REF,
	OPEN,
	CLOSE,
	MINMOD,
	GPOS,
	BRANCH,
	BRANCH,
	END,
	WHILEM,
	ALNUM,
	ALNUM,
	NALNUM,
	NALNUM,
	SPACE,
	SPACE,
	NSPACE,
	NSPACE,
	DIGIT,
	NDIGIT,
};
#endif

/* The following have no fixed length. */
#ifndef DOINIT
EXT char varies[];
#else
EXT char varies[] = {
    BRANCH, BACK, STAR, PLUS, CURLY, CURLYX, REF, REFF, REFFL, WHILEM, 0
};
#endif

/* The following always have a length of 1. */
#ifndef DOINIT
EXT char simple[];
#else
EXT char simple[] = {
    ANY, SANY, ANYOF,
    ALNUM, ALNUML, NALNUM, NALNUML,
    SPACE, SPACEL, NSPACE, NSPACEL,
    DIGIT, NDIGIT, 0
};
#endif

EXT char regdummy;

/*
 * A node is one char of opcode followed by two chars of "next" pointer.
 * "Next" pointers are stored as two 8-bit pieces, high order first.  The
 * value is a positive offset from the opcode of the node containing it.
 * An operand, if any, simply follows the node.  (Note that much of the
 * code generation knows about this implicit relationship.)
 *
 * Using two bytes for the "next" pointer is vast overkill for most things,
 * but allows patterns to get big without disasters.
 *
 * [If REGALIGN is defined, the "next" pointer is always aligned on an even
 * boundary, and reads the offset directly as a short.  Also, there is no
 * special test to reverse the sign of BACK pointers since the offset is
 * stored negative.]
 */

#ifndef gould
#ifndef cray
#ifndef eta10
#define REGALIGN
#endif
#endif
#endif

#define	OP(p)	(*(p))

#ifndef lint
#ifdef REGALIGN
#define NEXT(p) (*(short*)(p+1))
#define ARG1(p) (*(unsigned short*)(p+3))
#define ARG2(p) (*(unsigned short*)(p+5))
#else
#define	NEXT(p)	(((*((p)+1)&0377)<<8) + (*((p)+2)&0377))
#define	ARG1(p)	(((*((p)+3)&0377)<<8) + (*((p)+4)&0377))
#define	ARG2(p)	(((*((p)+5)&0377)<<8) + (*((p)+6)&0377))
#endif
#else /* lint */
#define NEXT(p) 0
#endif /* lint */

#define	OPERAND(p)	((p) + 3)

#ifdef REGALIGN
#define	NEXTOPER(p)	((p) + 4)
#define	PREVOPER(p)	((p) - 4)
#else
#define	NEXTOPER(p)	((p) + 3)
#define	PREVOPER(p)	((p) - 3)
#endif

#define MAGIC 0234

/* Flags for first parameter byte of ANYOF */
#define ANYOF_INVERT	0x40
#define ANYOF_FOLD	0x20
#define ANYOF_LOCALE	0x10
#define ANYOF_ISA	0x0F
#define ANYOF_ALNUML	 0x08
#define ANYOF_NALNUML	 0x04
#define ANYOF_SPACEL	 0x02
#define ANYOF_NSPACEL	 0x01

/*
 * Utility definitions.
 */
#ifndef lint
#ifndef CHARMASK
#define	UCHARAT(p)	((int)*(unsigned char *)(p))
#else
#define	UCHARAT(p)	((int)*(p)&CHARMASK)
#endif
#else /* lint */
#define UCHARAT(p)	regdummy
#endif /* lint */

#define	FAIL(m)	croak("/%.127s/: %s",regprecomp,m)
Commit	Line	Data
a0d0e21e	1	/* regcomp.h
a687059c LW	2	*/
	3
	4	/*
	5	* The "internal use only" fields in regexp.h are present to pass info from
	6	* compile to execute that permits the execute phase to run lots faster on
	7	* simple cases. They are:
	8	*
79072805	9	* regstart sv that must begin a match; Nullch if none obvious
a687059c LW	10	* reganch is the match anchored (at beginning-of-line only)?
a687059c LW	11	* regmust string (pointer into program) that match must include, or NULL
79072805	12	* [regmust changed to SV* for bminstr()--law]
a687059c LW	13	* regmlen length of regmust string
	14	* [regmlen not used currently]
	15	*
	16	* Regstart and reganch permit very fast decisions on suitable starting points
	17	* for a match, cutting down the work a lot. Regmust permits fast rejection
	18	* of lines that cannot possibly match. The regmust tests are costly enough
e50aee73	19	* that pregcomp() supplies a regmust only if the r.e. contains something
a687059c LW	20	* potentially expensive (at present, the only such thing detected is * or +
a687059c LW	21	* at the start of the r.e., which can involve a lot of backup). Regmlen is
e50aee73	22	* supplied because the test in pregexec() needs it and pregcomp() is computing
a687059c LW	23	* it anyway.
	24	* [regmust is now supplied always. The tests that use regmust have a
	25	* heuristic that disables the test if it usually matches.]
	26	*
	27	* [In fact, we now use regmust in many cases to locate where the search
	28	* starts in the string, so if regback is >= 0, the regmust search is never
	29	* wasted effort. The regback variable says how many characters back from
	30	* where regmust matched is the earliest possible start of the match.
	31	* For instance, /[a-z].foo/ has a regmust of 'foo' and a regback of 2.]
	32	*/
	33
	34	/*
	35	* Structure for regexp "program". This is essentially a linear encoding
	36	* of a nondeterministic finite-state machine (aka syntax charts or
	37	* "railroad normal form" in parsing technology). Each node is an opcode
	38	* plus a "next" pointer, possibly plus an operand. "Next" pointers of
	39	* all nodes except BRANCH implement concatenation; a "next" pointer with
	40	* a BRANCH on both ends of it is connecting two alternatives. (Here we
	41	* have one of the subtle syntax dependencies: an individual BRANCH (as
	42	* opposed to a collection of them) is never concatenated with anything
	43	* because of operator precedence.) The operand of some types of node is
	44	* a literal string; for others, it is a node leading into a sub-FSM. In
	45	* particular, the operand of a BRANCH node is the first node of the branch.
	46	* (NB this is not a tree structure: the tail of the branch connects
	47	* to the thing following the set of BRANCHes.) The opcodes are:
	48	*/
	49
	50	/* definition number opnd? meaning */
bbce6d69	51	#define END 0 /* no End of program. */
	52	#define BOL 1 /* no Match "" at beginning of line. */
	53	#define MBOL 2 /* no Same, assuming multiline. */
	54	#define SBOL 3 /* no Same, assuming singleline. */
	55	#define EOL 4 /* no Match "" at end of line. */
	56	#define MEOL 5 /* no Same, assuming multiline. */
	57	#define SEOL 6 /* no Same, assuming singleline. */
	58	#define ANY 7 /* no Match any one character (except newline). */
	59	#define SANY 8 /* no Match any one character. */
	60	#define ANYOF 9 /* sv Match character in (or not in) this class. */
a0d0e21e LW	61	#define CURLY 10 /* sv Match this simple thing {n,m} times. */
	62	#define CURLYX 11 /* sv Match this complex thing {n,m} times. */
	63	#define BRANCH 12 /* node Match this alternative, or the next... */
	64	#define BACK 13 /* no Match "", "next" ptr points backward. */
bbce6d69	65	#define EXACT 14 /* sv Match this string (preceded by length). */
	66	#define EXACTF 15 /* sv Match this string, folded (prec. by length). */
	67	#define EXACTFL 16 /* sv Match this string, folded in locale (w/len). */
	68	#define NOTHING 17 /* no Match empty string. */
	69	#define STAR 18 /* node Match this (simple) thing 0 or more times. */
	70	#define PLUS 19 /* node Match this (simple) thing 1 or more times. */
a0d0e21e	71	#define BOUND 20 /* no Match "" at any word boundary */
bbce6d69	72	#define BOUNDL 21 /* no Match "" at any word boundary */
	73	#define NBOUND 22 /* no Match "" at any word non-boundary */
	74	#define NBOUNDL 23 /* no Match "" at any word non-boundary */
c8756f30 AK	75	#define REF 24 /* num Match already matched string */
	76	#define REFF 25 /* num Match already matched string, folded */
	77	#define REFFL 26 /* num Match already matched string, folded in loc. */
	78	#define OPEN 27 /* num Mark this point in input as start of #n. */
	79	#define CLOSE 28 /* num Analogous to OPEN. */
	80	#define MINMOD 29 /* no Next operator is not greedy. */
	81	#define GPOS 30 /* no Matches where last m//g left off. */
	82	#define IFMATCH 31 /* no Succeeds if the following matches. */
	83	#define UNLESSM 32 /* no Fails if the following matches. */
	84	#define SUCCEED 33 /* no Return from a subroutine, basically. */
	85	#define WHILEM 34 /* no Do curly processing and see if rest matches. */
	86	#define ALNUM 35 /* no Match any alphanumeric character */
	87	#define ALNUML 36 /* no Match any alphanumeric char in locale */
	88	#define NALNUM 37 /* no Match any non-alphanumeric character */
	89	#define NALNUML 38 /* no Match any non-alphanumeric char in locale */
	90	#define SPACE 39 /* no Match any whitespace character */
	91	#define SPACEL 40 /* no Match any whitespace char in locale */
	92	#define NSPACE 41 /* no Match any non-whitespace character */
	93	#define NSPACEL 42 /* no Match any non-whitespace char in locale */
	94	#define DIGIT 43 /* no Match any numeric character */
	95	#define NDIGIT 44 /* no Match any non-numeric character */
a687059c LW	96
	97	/*
	98	* Opcode notes:
	99	*
	100	* BRANCH The set of branches constituting a single choice are hooked
	101	* together with their "next" pointers, since precedence prevents
	102	* anything being concatenated to any individual branch. The
	103	* "next" pointer of the last BRANCH in a choice points to the
	104	* thing following the whole choice. This is also where the
	105	* final "next" pointer of each individual branch points; each
	106	* branch starts with the operand node of a BRANCH node.
	107	*
	108	* BACK Normal "next" pointers all implicitly point forward; BACK
	109	* exists to make loop structures possible.
	110	*
	111	* STAR,PLUS '?', and complex '*' and '+', are implemented as circular
	112	* BRANCH structures using BACK. Simple cases (one character
	113	* per match) are implemented with STAR and PLUS for speed
	114	* and to minimize recursive plunges.
	115	*
	116	* OPEN,CLOSE ...are numbered at compile time.
	117	*/
	118
fe14fcc3	119	#ifndef DOINIT
a0d0e21e LW	120	EXT char regarglen[];
a0d0e21e LW	121	#else
bbce6d69	122	EXT char regarglen[] = {
	123	0,0,0,0,0,0,0,0,0,0,
	124	/CURLY/ 4, /CURLYX/ 4,
	125	0,0,0,0,0,0,0,0,0,0,0,0,
c8756f30	126	/REF/ 2, 2, 2, /OPEN/ 2, /CLOSE/ 2,
bbce6d69	127	0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
bbce6d69	128	};
a0d0e21e LW	129	#endif
	130
	131	#ifndef DOINIT
	132	EXT char regkind[];
fe14fcc3	133	#else
a0d0e21e LW	134	EXT char regkind[] = {
	135	END,
	136	BOL,
	137	BOL,
	138	BOL,
	139	EOL,
	140	EOL,
	141	EOL,
	142	ANY,
	143	ANY,
	144	ANYOF,
	145	CURLY,
	146	CURLY,
	147	BRANCH,
	148	BACK,
bbce6d69	149	EXACT,
	150	EXACT,
	151	EXACT,
a0d0e21e LW	152	NOTHING,
	153	STAR,
	154	PLUS,
bbce6d69	155	BOUND,
a0d0e21e LW	156	BOUND,
a0d0e21e LW	157	NBOUND,
bbce6d69	158	NBOUND,
a0d0e21e	159	REF,
c8756f30 AK	160	REF,
c8756f30 AK	161	REF,
a0d0e21e LW	162	OPEN,
	163	CLOSE,
	164	MINMOD,
774d564b	165	GPOS,
a0d0e21e LW	166	BRANCH,
	167	BRANCH,
	168	END,
bbce6d69	169	WHILEM,
	170	ALNUM,
	171	ALNUM,
	172	NALNUM,
	173	NALNUM,
	174	SPACE,
	175	SPACE,
	176	NSPACE,
	177	NSPACE,
	178	DIGIT,
	179	NDIGIT,
a0d0e21e	180	};
fe14fcc3 LW	181	#endif
fe14fcc3 LW	182
a687059c LW	183	/* The following have no fixed length. */
a687059c LW	184	#ifndef DOINIT
a0d0e21e	185	EXT char varies[];
a687059c	186	#else
bbce6d69	187	EXT char varies[] = {
c8756f30	188	BRANCH, BACK, STAR, PLUS, CURLY, CURLYX, REF, REFF, REFFL, WHILEM, 0
bbce6d69	189	};
a687059c LW	190	#endif
	191
	192	/* The following always have a length of 1. */
	193	#ifndef DOINIT
a0d0e21e	194	EXT char simple[];
a687059c	195	#else
bbce6d69	196	EXT char simple[] = {
	197	ANY, SANY, ANYOF,
	198	ALNUM, ALNUML, NALNUM, NALNUML,
	199	SPACE, SPACEL, NSPACE, NSPACEL,
	200	DIGIT, NDIGIT, 0
	201	};
a687059c LW	202	#endif
	203
	204	EXT char regdummy;
	205
	206	/*
	207	* A node is one char of opcode followed by two chars of "next" pointer.
	208	* "Next" pointers are stored as two 8-bit pieces, high order first. The
	209	* value is a positive offset from the opcode of the node containing it.
	210	* An operand, if any, simply follows the node. (Note that much of the
	211	* code generation knows about this implicit relationship.)
	212	*
	213	* Using two bytes for the "next" pointer is vast overkill for most things,
	214	* but allows patterns to get big without disasters.
	215	*
	216	* [If REGALIGN is defined, the "next" pointer is always aligned on an even
	217	* boundary, and reads the offset directly as a short. Also, there is no
	218	* special test to reverse the sign of BACK pointers since the offset is
	219	* stored negative.]
	220	*/
	221
	222	#ifndef gould
	223	#ifndef cray
34de22dd	224	#ifndef eta10
a687059c LW	225	#define REGALIGN
	226	#endif
	227	#endif
34de22dd	228	#endif
a687059c LW	229
	230	#define OP(p) (*(p))
	231
	232	#ifndef lint
	233	#ifdef REGALIGN
	234	#define NEXT(p) ((short)(p+1))
00bf170e LW	235	#define ARG1(p) ((unsigned short)(p+3))
00bf170e LW	236	#define ARG2(p) ((unsigned short)(p+5))
a687059c LW	237	#else
a687059c LW	238	#define NEXT(p) (((((p)+1)&0377)<<8) + (((p)+2)&0377))
00bf170e LW	239	#define ARG1(p) (((((p)+3)&0377)<<8) + (((p)+4)&0377))
00bf170e LW	240	#define ARG2(p) (((((p)+5)&0377)<<8) + (((p)+6)&0377))
a687059c LW	241	#endif
	242	#else /* lint */
	243	#define NEXT(p) 0
	244	#endif /* lint */
	245
	246	#define OPERAND(p) ((p) + 3)
	247
	248	#ifdef REGALIGN
	249	#define NEXTOPER(p) ((p) + 4)
a0d0e21e	250	#define PREVOPER(p) ((p) - 4)
a687059c LW	251	#else
a687059c LW	252	#define NEXTOPER(p) ((p) + 3)
a0d0e21e	253	#define PREVOPER(p) ((p) - 3)
a687059c LW	254	#endif
	255
	256	#define MAGIC 0234
	257
bbce6d69	258	/* Flags for first parameter byte of ANYOF */
	259	#define ANYOF_INVERT 0x40
	260	#define ANYOF_FOLD 0x20
	261	#define ANYOF_LOCALE 0x10
	262	#define ANYOF_ISA 0x0F
	263	#define ANYOF_ALNUML 0x08
	264	#define ANYOF_NALNUML 0x04
	265	#define ANYOF_SPACEL 0x02
	266	#define ANYOF_NSPACEL 0x01
	267
a687059c LW	268	/*
	269	* Utility definitions.
	270	*/
	271	#ifndef lint
2304df62	272	#ifndef CHARMASK
a687059c LW	273	#define UCHARAT(p) ((int)(unsigned char )(p))
a687059c LW	274	#else
2304df62	275	#define UCHARAT(p) ((int)*(p)&CHARMASK)
a687059c LW	276	#endif
	277	#else /* lint */
	278	#define UCHARAT(p) regdummy
	279	#endif /* lint */
	280
a0d0e21e	281	#define FAIL(m) croak("/%.127s/: %s",regprecomp,m)