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postgresql/src/include/regex/regguts.h

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/*
* Internal interface definitions, etc., for the reg package
*
* Copyright (c) 1998, 1999 Henry Spencer. All rights reserved.
*
* Development of this software was funded, in part, by Cray Research Inc.,
* UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics
* Corporation, none of whom are responsible for the results. The author
* thanks all of them.
*
* Redistribution and use in source and binary forms -- with or without
* modification -- are permitted for any purpose, provided that
* redistributions in source form retain this entire copyright notice and
* indicate the origin and nature of any modifications.
*
* I'd appreciate being given credit for this package in the documentation
* of software which uses it, but that is not a requirement.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* HENRY SPENCER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* src/include/regex/regguts.h
*/
/*
* Environmental customization. It should not (I hope) be necessary to
* alter the file you are now reading -- regcustom.h should handle it all,
* given care here and elsewhere.
*/
#include "regcustom.h"
/*
* Things that regcustom.h might override.
*/
/* assertions */
#ifndef assert
#ifndef REG_DEBUG
#define NDEBUG /* no assertions */
#endif
#include <assert.h>
#endif
/* voids */
#ifndef DISCARD
#define DISCARD void /* for throwing values away */
#endif
#ifndef VS
#define VS(x) ((void *)(x)) /* cast something to generic ptr */
#endif
/* function-pointer declarator */
#ifndef FUNCPTR
#define FUNCPTR(name, args) (*(name)) args
#endif
/* memory allocation */
#ifndef MALLOC
#define MALLOC(n) malloc(n)
#endif
#ifndef REALLOC
#define REALLOC(p, n) realloc(VS(p), n)
#endif
#ifndef FREE
#define FREE(p) free(VS(p))
#endif
/* interruption */
#ifndef INTERRUPT
#define INTERRUPT(re)
#endif
/* want size of a char in bits, and max value in bounded quantifiers */
#ifndef _POSIX2_RE_DUP_MAX
#define _POSIX2_RE_DUP_MAX 255 /* normally from <limits.h> */
#endif
/*
* misc
*/
#define NOTREACHED 0
#define DUPMAX _POSIX2_RE_DUP_MAX
#define DUPINF (DUPMAX+1)
#define REMAGIC 0xfed7 /* magic number for main struct */
/* Type codes for lookaround constraints */
#define LATYPE_AHEAD_POS 03 /* positive lookahead */
#define LATYPE_AHEAD_NEG 02 /* negative lookahead */
#define LATYPE_BEHIND_POS 01 /* positive lookbehind */
#define LATYPE_BEHIND_NEG 00 /* negative lookbehind */
#define LATYPE_IS_POS(la) ((la) & 01)
#define LATYPE_IS_AHEAD(la) ((la) & 02)
/*
* debugging facilities
*/
#ifdef REG_DEBUG
/* FDEBUG does finite-state tracing */
#define FDEBUG(arglist) { if (v->eflags&REG_FTRACE) printf arglist; }
/* MDEBUG does higher-level tracing */
#define MDEBUG(arglist) { if (v->eflags&REG_MTRACE) printf arglist; }
#else
#define FDEBUG(arglist) {}
#define MDEBUG(arglist) {}
#endif
/*
* bitmap manipulation
*/
#define UBITS (CHAR_BIT * sizeof(unsigned))
#define BSET(uv, sn) ((uv)[(sn)/UBITS] |= (unsigned)1 << ((sn)%UBITS))
#define ISBSET(uv, sn) ((uv)[(sn)/UBITS] & ((unsigned)1 << ((sn)%UBITS)))
/*
* known character classes
*/
enum char_classes
{
CC_ALNUM, CC_ALPHA, CC_ASCII, CC_BLANK, CC_CNTRL, CC_DIGIT, CC_GRAPH,
CC_LOWER, CC_PRINT, CC_PUNCT, CC_SPACE, CC_UPPER, CC_XDIGIT, CC_WORD
};
#define NUM_CCLASSES 14
/*
* As soon as possible, we map chrs into equivalence classes -- "colors" --
* which are of much more manageable number.
*
* To further reduce the number of arcs in NFAs and DFAs, we also have a
* special RAINBOW "color" that can be assigned to an arc. This is not a
* real color, in that it has no entry in color maps.
*/
typedef short color; /* colors of characters */
#define MAX_COLOR 32767 /* max color (must fit in 'color' datatype) */
#define COLORLESS (-1) /* impossible color */
#define RAINBOW (-2) /* represents all colors except pseudocolors */
#define WHITE 0 /* default color, parent of all others */
/* Note: various places in the code know that WHITE is zero */
/*
* Per-color data structure for the compile-time color machinery
*
* If "sub" is not NOSUB then it is the number of the color's current
* subcolor, i.e. we are in process of dividing this color (character
* equivalence class) into two colors. See src/backend/regex/README for
* discussion of subcolors.
*
* Currently-unused colors have the FREECOL bit set and are linked into a
* freelist using their "sub" fields, but only if their color numbers are
* less than colormap.max. Any array entries beyond "max" are just garbage.
*/
struct colordesc
{
int nschrs; /* number of simple chars of this color */
int nuchrs; /* number of upper map entries of this color */
color sub; /* open subcolor, if any; or free-chain ptr */
#define NOSUB COLORLESS /* value of "sub" when no open subcolor */
struct arc *arcs; /* chain of all arcs of this color */
chr firstchr; /* simple char first assigned to this color */
int flags; /* bitmask of the following flags: */
#define FREECOL 01 /* currently free */
#define PSEUDO 02 /* pseudocolor, no real chars */
#define COLMARK 04 /* temporary marker used in some functions */
};
#define UNUSEDCOLOR(cd) ((cd)->flags & FREECOL)
/*
* The color map itself
*
* This struct holds both data used only at compile time, and the chr to
* color mapping information, used at both compile and run time. The latter
* is the bulk of the space, so it's not really worth separating out the
* compile-only portion.
*
* Ideally, the mapping data would just be an array of colors indexed by
* chr codes; but for large character sets that's impractical. Fortunately,
* common characters have smaller codes, so we can use a simple array for chr
* codes up to MAX_SIMPLE_CHR, and do something more complex for codes above
* that, without much loss of performance. The "something more complex" is a
* 2-D array of color entries, where row indexes correspond to individual chrs
* or chr ranges that have been mentioned in the regex (with row zero
* representing all other chrs), and column indexes correspond to different
* sets of locale-dependent character classes such as "isalpha". The
* classbits[k] entry is zero if we do not care about the k'th character class
* in this regex, and otherwise it is the bit to be OR'd into the column index
* if the character in question is a member of that class. We find the color
* of a high-valued chr by identifying which colormaprange it is in to get
* the row index (use row zero if it's in none of them), identifying which of
* the interesting cclasses it's in to get the column index, and then indexing
* into the 2-D hicolormap array.
*
* The colormapranges are required to be nonempty, nonoverlapping, and to
* appear in increasing chr-value order.
*/
typedef struct colormaprange
{
chr cmin; /* range represents cmin..cmax inclusive */
chr cmax;
int rownum; /* row index in hicolormap array (>= 1) */
} colormaprange;
struct colormap
{
int magic;
#define CMMAGIC 0x876
struct vars *v; /* for compile error reporting */
size_t ncds; /* allocated length of colordescs array */
size_t max; /* highest color number currently in use */
color free; /* beginning of free chain (if non-0) */
struct colordesc *cd; /* pointer to array of colordescs */
#define CDEND(cm) (&(cm)->cd[(cm)->max + 1])
/* mapping data for chrs <= MAX_SIMPLE_CHR: */
color *locolormap; /* simple array indexed by chr code */
/* mapping data for chrs > MAX_SIMPLE_CHR: */
int classbits[NUM_CCLASSES]; /* see comment above */
int numcmranges; /* number of colormapranges */
colormaprange *cmranges; /* ranges of high chrs */
color *hicolormap; /* 2-D array of color entries */
int maxarrayrows; /* number of array rows allocated */
int hiarrayrows; /* number of array rows in use */
int hiarraycols; /* number of array columns (2^N) */
/* If we need up to NINLINECDS, we store them here to save a malloc */
#define NINLINECDS ((size_t) 10)
struct colordesc cdspace[NINLINECDS];
};
/* fetch color for chr; beware of multiple evaluation of c argument */
#define GETCOLOR(cm, c) \
((c) <= MAX_SIMPLE_CHR ? (cm)->locolormap[(c) - CHR_MIN] : pg_reg_getcolor(cm, c))
/*
* Interface definitions for locale-interface functions in regc_locale.c.
*/
/*
* Representation of a set of characters. chrs[] represents individual
* code points, ranges[] represents ranges in the form min..max inclusive.
*
* If the cvec represents a locale-specific character class, eg [[:alpha:]],
* then the chrs[] and ranges[] arrays contain only members of that class
* up to MAX_SIMPLE_CHR (inclusive). cclasscode is set to regc_locale.c's
* code for the class, rather than being -1 as it is in an ordinary cvec.
*
* Note that in cvecs gotten from newcvec() and intended to be freed by
* freecvec(), both arrays of chrs are after the end of the struct, not
* separately malloc'd; so chrspace and rangespace are effectively immutable.
*/
struct cvec
{
int nchrs; /* number of chrs */
int chrspace; /* number of chrs allocated in chrs[] */
chr *chrs; /* pointer to vector of chrs */
int nranges; /* number of ranges (chr pairs) */
int rangespace; /* number of ranges allocated in ranges[] */
chr *ranges; /* pointer to vector of chr pairs */
int cclasscode; /* value of "enum classes", or -1 */
};
/*
* definitions for NFA internal representation
*/
struct state;
struct arc
{
int type; /* 0 if free, else an NFA arc type code */
color co; /* color the arc matches (possibly RAINBOW) */
struct state *from; /* where it's from */
struct state *to; /* where it's to */
struct arc *outchain; /* link in *from's outs chain or free chain */
struct arc *outchainRev; /* back-link in *from's outs chain */
#define freechain outchain /* we do not maintain "freechainRev" */
struct arc *inchain; /* link in *to's ins chain */
struct arc *inchainRev; /* back-link in *to's ins chain */
/* these fields are not used when co == RAINBOW: */
struct arc *colorchain; /* link in color's arc chain */
struct arc *colorchainRev; /* back-link in color's arc chain */
};
struct arcbatch
{ /* for bulk allocation of arcs */
struct arcbatch *next; /* chain link */
size_t narcs; /* number of arcs allocated in this arcbatch */
struct arc a[FLEXIBLE_ARRAY_MEMBER];
};
#define ARCBATCHSIZE(n) ((n) * sizeof(struct arc) + offsetof(struct arcbatch, a))
/* first batch will have FIRSTABSIZE arcs; then double it until MAXABSIZE */
#define FIRSTABSIZE 64
#define MAXABSIZE 1024
struct state
{
int no; /* state number, zero and up; or FREESTATE */
#define FREESTATE (-1)
char flag; /* marks special states */
int nins; /* number of inarcs */
int nouts; /* number of outarcs */
struct arc *ins; /* chain of inarcs */
struct arc *outs; /* chain of outarcs */
struct state *tmp; /* temporary for traversal algorithms */
struct state *next; /* chain for traversing all live states */
/* the "next" field is also used to chain free states together */
struct state *prev; /* back-link in chain of all live states */
};
struct statebatch
{ /* for bulk allocation of states */
struct statebatch *next; /* chain link */
size_t nstates; /* number of states allocated in this batch */
struct state s[FLEXIBLE_ARRAY_MEMBER];
};
#define STATEBATCHSIZE(n) ((n) * sizeof(struct state) + offsetof(struct statebatch, s))
/* first batch will have FIRSTSBSIZE states; then double it until MAXSBSIZE */
#define FIRSTSBSIZE 32
#define MAXSBSIZE 1024
struct nfa
{
struct state *pre; /* pre-initial state */
struct state *init; /* initial state */
struct state *final; /* final state */
struct state *post; /* post-final state */
int nstates; /* for numbering states */
struct state *states; /* chain of live states */
struct state *slast; /* tail of the chain */
struct state *freestates; /* chain of free states */
struct arc *freearcs; /* chain of free arcs */
struct statebatch *lastsb; /* chain of statebatches */
struct arcbatch *lastab; /* chain of arcbatches */
size_t lastsbused; /* number of states consumed from *lastsb */
size_t lastabused; /* number of arcs consumed from *lastab */
struct colormap *cm; /* the color map */
color bos[2]; /* colors, if any, assigned to BOS and BOL */
color eos[2]; /* colors, if any, assigned to EOS and EOL */
int flags; /* flags to pass forward to cNFA */
int minmatchall; /* min number of chrs to match, if matchall */
int maxmatchall; /* max number of chrs to match, or DUPINF */
struct vars *v; /* simplifies compile error reporting */
struct nfa *parent; /* parent NFA, if any */
};
/*
* definitions for compacted NFA
*
* The main space savings in a compacted NFA is from making the arcs as small
* as possible. We store only the transition color and next-state number for
* each arc. The list of out arcs for each state is an array beginning at
* cnfa.states[statenumber], and terminated by a dummy carc struct with
* co == COLORLESS.
*
* The non-dummy carc structs are of two types: plain arcs and LACON arcs.
* Plain arcs just store the transition color number as "co". LACON arcs
* store the lookaround constraint number plus cnfa.ncolors as "co". LACON
* arcs can be distinguished from plain by testing for co >= cnfa.ncolors.
*
* Note that in a plain arc, "co" can be RAINBOW; since that's negative,
* it doesn't break the rule about how to recognize LACON arcs.
*
* We have special markings for "trivial" NFAs that can match any string
* (possibly with limits on the number of characters therein). In such a
* case, flags & MATCHALL is set (and HASLACONS can't be set). Then the
* fields minmatchall and maxmatchall give the minimum and maximum numbers
* of characters to match. For example, ".*" produces minmatchall = 0
* and maxmatchall = DUPINF, while ".+" produces minmatchall = 1 and
* maxmatchall = DUPINF.
*/
struct carc
{
color co; /* COLORLESS is list terminator */
int to; /* next-state number */
};
struct cnfa
{
int nstates; /* number of states */
int ncolors; /* number of colors (max color in use + 1) */
int flags; /* bitmask of the following flags: */
#define HASLACONS 01 /* uses lookaround constraints */
#define MATCHALL 02 /* matches all strings of a range of lengths */
int pre; /* setup state number */
int post; /* teardown state number */
color bos[2]; /* colors, if any, assigned to BOS and BOL */
color eos[2]; /* colors, if any, assigned to EOS and EOL */
char *stflags; /* vector of per-state flags bytes */
#define CNFA_NOPROGRESS 01 /* flag bit for a no-progress state */
struct carc **states; /* vector of pointers to outarc lists */
/* states[n] are pointers into a single malloc'd array of arcs */
struct carc *arcs; /* the area for the lists */
/* these fields are used only in a MATCHALL NFA (else they're -1): */
int minmatchall; /* min number of chrs to match */
int maxmatchall; /* max number of chrs to match, or DUPINF */
};
/*
* When debugging, it's helpful if an un-filled CNFA is all-zeroes.
* In production, though, we only require nstates to be zero.
*/
#ifdef REG_DEBUG
#define ZAPCNFA(cnfa) memset(&(cnfa), 0, sizeof(cnfa))
#else
#define ZAPCNFA(cnfa) ((cnfa).nstates = 0)
#endif
#define NULLCNFA(cnfa) ((cnfa).nstates == 0)
/*
* This symbol limits the transient heap space used by the regex compiler,
* and thereby also the maximum complexity of NFAs that we'll deal with.
* Currently we only count NFA states and arcs against this; the other
* transient data is generally not large enough to notice compared to those.
* Note that we do not charge anything for the final output data structures
* (the compacted NFA and the colormap).
* The scaling here is based on an empirical measurement that very large
* NFAs tend to have about 4 arcs/state.
*/
#ifndef REG_MAX_COMPILE_SPACE
#define REG_MAX_COMPILE_SPACE \
(500000 * (sizeof(struct state) + 4 * sizeof(struct arc)))
#endif
/*
* subexpression tree
*
* "op" is one of:
* '=' plain regex without interesting substructure (implemented as DFA)
* 'b' back-reference (has no substructure either)
* '(' no-op capture node: captures the match of its single child
* '.' concatenation: matches a match for first child, then second child
* '|' alternation: matches a match for any of its children
* '*' iteration: matches some number of matches of its single child
*
* An alternation node can have any number of children (but at least two),
* linked through their sibling fields.
*
* A concatenation node must have exactly two children. It might be useful
* to support more, but that would complicate the executor. Note that it is
* the first child's greediness that determines the node's preference for
* where to split a match.
*
* Note: when a backref is directly quantified, we stick the min/max counts
* into the backref rather than plastering an iteration node on top. This is
* for efficiency: there is no need to search for possible division points.
*/
struct subre
{
char op; /* see type codes above */
char flags;
#define LONGER 01 /* prefers longer match */
#define SHORTER 02 /* prefers shorter match */
#define MIXED 04 /* mixed preference below */
#define CAP 010 /* capturing parens here or below */
#define BACKR 020 /* back reference here or below */
#define BRUSE 040 /* is referenced by a back reference */
#define INUSE 0100 /* in use in final tree */
#define UPPROP (MIXED|CAP|BACKR) /* flags which should propagate up */
#define LMIX(f) ((f)<<2) /* LONGER -> MIXED */
#define SMIX(f) ((f)<<1) /* SHORTER -> MIXED */
#define UP(f) (((f)&UPPROP) | (LMIX(f) & SMIX(f) & MIXED))
#define MESSY(f) ((f)&(MIXED|CAP|BACKR))
#define PREF(f) ((f)&(LONGER|SHORTER))
#define PREF2(f1, f2) ((PREF(f1) != 0) ? PREF(f1) : PREF(f2))
#define COMBINE(f1, f2) (UP((f1)|(f2)) | PREF2(f1, f2))
char latype; /* LATYPE code, if lookaround constraint */
int id; /* ID of subre (1..ntree-1) */
int capno; /* if capture node, subno to capture into */
int backno; /* if backref node, subno it refers to */
short min; /* min repetitions for iteration or backref */
short max; /* max repetitions for iteration or backref */
struct subre *child; /* first child, if any (also freelist chain) */
struct subre *sibling; /* next child of same parent, if any */
struct state *begin; /* outarcs from here... */
struct state *end; /* ...ending in inarcs here */
struct cnfa cnfa; /* compacted NFA, if any */
struct subre *chain; /* for bookkeeping and error cleanup */
};
/*
* table of function pointers for generic manipulation functions
* A regex_t's re_fns points to one of these.
*/
struct fns
{
void FUNCPTR(free, (regex_t *));
int FUNCPTR(stack_too_deep, (void));
};
#define STACK_TOO_DEEP(re) \
((*((struct fns *) (re)->re_fns)->stack_too_deep) ())
/*
* the insides of a regex_t, hidden behind a void *
*/
struct guts
{
int magic;
#define GUTSMAGIC 0xfed9
int cflags; /* copy of compile flags */
long info; /* copy of re_info */
size_t nsub; /* copy of re_nsub */
struct subre *tree;
struct cnfa search; /* for fast preliminary search */
int ntree; /* number of subre's, plus one */
struct colormap cmap;
int FUNCPTR(compare, (const chr *, const chr *, size_t));
struct subre *lacons; /* lookaround-constraint vector */
int nlacons; /* size of lacons[]; note that only slots
* numbered 1 .. nlacons-1 are used */
};
/* prototypes for functions that are exported from regcomp.c to regexec.c */
extern void pg_set_regex_collation(Oid collation);
extern color pg_reg_getcolor(struct colormap *cm, chr c);
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