471 lines
15 KiB
C
471 lines
15 KiB
C
/*
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* Internal interface definitions, etc., for the reg package
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*
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* Copyright (c) 1998, 1999 Henry Spencer. All rights reserved.
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*
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* Development of this software was funded, in part, by Cray Research Inc.,
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* UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics
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* Corporation, none of whom are responsible for the results. The author
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* thanks all of them.
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*
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* Redistribution and use in source and binary forms -- with or without
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* modification -- are permitted for any purpose, provided that
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* redistributions in source form retain this entire copyright notice and
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* indicate the origin and nature of any modifications.
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*
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* I'd appreciate being given credit for this package in the documentation
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* of software which uses it, but that is not a requirement.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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* HENRY SPENCER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* src/include/regex/regguts.h
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*/
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/*
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* Environmental customization. It should not (I hope) be necessary to
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* alter the file you are now reading -- regcustom.h should handle it all,
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* given care here and elsewhere.
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*/
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#include "regcustom.h"
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/*
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* Things that regcustom.h might override.
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*/
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/* assertions */
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#ifndef assert
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#ifndef REG_DEBUG
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#define NDEBUG /* no assertions */
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#endif
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#include <assert.h>
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#endif
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/* voids */
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#ifndef DISCARD
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#define DISCARD void /* for throwing values away */
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#endif
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#ifndef VS
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#define VS(x) ((void *)(x)) /* cast something to generic ptr */
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#endif
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/* function-pointer declarator */
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#ifndef FUNCPTR
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#define FUNCPTR(name, args) (*(name)) args
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#endif
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/* memory allocation */
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#ifndef MALLOC
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#define MALLOC(n) malloc(n)
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#endif
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#ifndef REALLOC
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#define REALLOC(p, n) realloc(VS(p), n)
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#endif
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#ifndef FREE
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#define FREE(p) free(VS(p))
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#endif
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/* want size of a char in bits, and max value in bounded quantifiers */
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#ifndef CHAR_BIT
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#include <limits.h>
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#endif
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#ifndef _POSIX2_RE_DUP_MAX
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#define _POSIX2_RE_DUP_MAX 255 /* normally from <limits.h> */
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#endif
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/*
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* misc
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*/
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#define NOTREACHED 0
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#define xxx 1
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#define DUPMAX _POSIX2_RE_DUP_MAX
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#define INFINITY (DUPMAX+1)
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#define REMAGIC 0xfed7 /* magic number for main struct */
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/*
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* debugging facilities
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*/
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#ifdef REG_DEBUG
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/* FDEBUG does finite-state tracing */
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#define FDEBUG(arglist) { if (v->eflags®_FTRACE) printf arglist; }
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/* MDEBUG does higher-level tracing */
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#define MDEBUG(arglist) { if (v->eflags®_MTRACE) printf arglist; }
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#else
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#define FDEBUG(arglist) {}
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#define MDEBUG(arglist) {}
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#endif
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/*
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* bitmap manipulation
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*/
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#define UBITS (CHAR_BIT * sizeof(unsigned))
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#define BSET(uv, sn) ((uv)[(sn)/UBITS] |= (unsigned)1 << ((sn)%UBITS))
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#define ISBSET(uv, sn) ((uv)[(sn)/UBITS] & ((unsigned)1 << ((sn)%UBITS)))
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/*
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* We dissect a chr into byts for colormap table indexing. Here we define
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* a byt, which will be the same as a byte on most machines... The exact
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* size of a byt is not critical, but about 8 bits is good, and extraction
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* of 8-bit chunks is sometimes especially fast.
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*/
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#ifndef BYTBITS
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#define BYTBITS 8 /* bits in a byt */
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#endif
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#define BYTTAB (1<<BYTBITS) /* size of table with one entry per byt value */
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#define BYTMASK (BYTTAB-1) /* bit mask for byt */
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#define NBYTS ((CHRBITS+BYTBITS-1)/BYTBITS)
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/* the definition of GETCOLOR(), below, assumes NBYTS <= 4 */
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/*
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* As soon as possible, we map chrs into equivalence classes -- "colors" --
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* which are of much more manageable number.
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*/
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typedef short color; /* colors of characters */
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typedef int pcolor; /* what color promotes to */
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#define MAX_COLOR 32767 /* max color (must fit in 'color' datatype) */
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#define COLORLESS (-1) /* impossible color */
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#define WHITE 0 /* default color, parent of all others */
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/*
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* A colormap is a tree -- more precisely, a DAG -- indexed at each level
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* by a byt of the chr, to map the chr to a color efficiently. Because
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* lower sections of the tree can be shared, it can exploit the usual
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* sparseness of such a mapping table. The tree is always NBYTS levels
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* deep (in the past it was shallower during construction but was "filled"
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* to full depth at the end of that); areas that are unaltered as yet point
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* to "fill blocks" which are entirely WHITE in color.
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*/
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/* the tree itself */
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struct colors
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{
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color ccolor[BYTTAB];
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};
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struct ptrs
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{
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union tree *pptr[BYTTAB];
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};
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union tree
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{
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struct colors colors;
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struct ptrs ptrs;
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};
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#define tcolor colors.ccolor
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#define tptr ptrs.pptr
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/*
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* Per-color data structure for the compile-time color machinery
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*
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* If "sub" is not NOSUB then it is the number of the color's current
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* subcolor, i.e. we are in process of dividing this color (character
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* equivalence class) into two colors. See src/backend/regex/README for
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* discussion of subcolors.
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*
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* Currently-unused colors have the FREECOL bit set and are linked into a
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* freelist using their "sub" fields, but only if their color numbers are
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* less than colormap.max. Any array entries beyond "max" are just garbage.
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*/
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struct colordesc
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{
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uchr nchrs; /* number of chars of this color */
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color sub; /* open subcolor, if any; or free-chain ptr */
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#define NOSUB COLORLESS /* value of "sub" when no open subcolor */
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struct arc *arcs; /* chain of all arcs of this color */
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chr firstchr; /* char first assigned to this color */
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int flags; /* bit values defined next */
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#define FREECOL 01 /* currently free */
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#define PSEUDO 02 /* pseudocolor, no real chars */
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#define UNUSEDCOLOR(cd) ((cd)->flags & FREECOL)
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union tree *block; /* block of solid color, if any */
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};
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/*
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* The color map itself
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*
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* Much of the data in the colormap struct is only used at compile time.
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* However, the bulk of the space usage is in the "tree" structure, so it's
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* not clear that there's much point in converting the rest to a more compact
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* form when compilation is finished.
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*/
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struct colormap
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{
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int magic;
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#define CMMAGIC 0x876
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struct vars *v; /* for compile error reporting */
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size_t ncds; /* allocated length of colordescs array */
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size_t max; /* highest color number currently in use */
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color free; /* beginning of free chain (if non-0) */
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struct colordesc *cd; /* pointer to array of colordescs */
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#define CDEND(cm) (&(cm)->cd[(cm)->max + 1])
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/* If we need up to NINLINECDS, we store them here to save a malloc */
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#define NINLINECDS ((size_t)10)
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struct colordesc cdspace[NINLINECDS];
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union tree tree[NBYTS]; /* tree top, plus lower-level fill blocks */
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};
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/* optimization magic to do fast chr->color mapping */
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#define B0(c) ((c) & BYTMASK)
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#define B1(c) (((c)>>BYTBITS) & BYTMASK)
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#define B2(c) (((c)>>(2*BYTBITS)) & BYTMASK)
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#define B3(c) (((c)>>(3*BYTBITS)) & BYTMASK)
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#if NBYTS == 1
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#define GETCOLOR(cm, c) ((cm)->tree->tcolor[B0(c)])
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#endif
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/* beware, for NBYTS>1, GETCOLOR() is unsafe -- 2nd arg used repeatedly */
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#if NBYTS == 2
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#define GETCOLOR(cm, c) ((cm)->tree->tptr[B1(c)]->tcolor[B0(c)])
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#endif
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#if NBYTS == 4
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#define GETCOLOR(cm, c) ((cm)->tree->tptr[B3(c)]->tptr[B2(c)]->tptr[B1(c)]->tcolor[B0(c)])
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#endif
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/*
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* Interface definitions for locale-interface functions in regc_locale.c.
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*/
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/*
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* Representation of a set of characters. chrs[] represents individual
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* code points, ranges[] represents ranges in the form min..max inclusive.
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*
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* Note that in cvecs gotten from newcvec() and intended to be freed by
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* freecvec(), both arrays of chrs are after the end of the struct, not
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* separately malloc'd; so chrspace and rangespace are effectively immutable.
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*/
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struct cvec
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{
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int nchrs; /* number of chrs */
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int chrspace; /* number of chrs allocated in chrs[] */
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chr *chrs; /* pointer to vector of chrs */
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int nranges; /* number of ranges (chr pairs) */
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int rangespace; /* number of ranges allocated in ranges[] */
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chr *ranges; /* pointer to vector of chr pairs */
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};
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/*
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* definitions for NFA internal representation
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*
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* Having a "from" pointer within each arc may seem redundant, but it
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* saves a lot of hassle.
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*/
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struct state;
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struct arc
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{
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int type; /* 0 if free, else an NFA arc type code */
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color co;
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struct state *from; /* where it's from (and contained within) */
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struct state *to; /* where it's to */
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struct arc *outchain; /* link in *from's outs chain or free chain */
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#define freechain outchain
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struct arc *inchain; /* link in *to's ins chain */
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struct arc *colorchain; /* link in color's arc chain */
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struct arc *colorchainRev; /* back-link in color's arc chain */
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};
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struct arcbatch
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{ /* for bulk allocation of arcs */
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struct arcbatch *next;
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#define ABSIZE 10
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struct arc a[ABSIZE];
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};
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struct state
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{
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int no;
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#define FREESTATE (-1)
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char flag; /* marks special states */
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int nins; /* number of inarcs */
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struct arc *ins; /* chain of inarcs */
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int nouts; /* number of outarcs */
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struct arc *outs; /* chain of outarcs */
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struct arc *free; /* chain of free arcs */
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struct state *tmp; /* temporary for traversal algorithms */
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struct state *next; /* chain for traversing all */
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struct state *prev; /* back chain */
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struct arcbatch oas; /* first arcbatch, avoid malloc in easy case */
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int noas; /* number of arcs used in first arcbatch */
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};
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struct nfa
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{
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struct state *pre; /* pre-initial state */
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struct state *init; /* initial state */
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struct state *final; /* final state */
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struct state *post; /* post-final state */
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int nstates; /* for numbering states */
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struct state *states; /* state-chain header */
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struct state *slast; /* tail of the chain */
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struct state *free; /* free list */
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struct colormap *cm; /* the color map */
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color bos[2]; /* colors, if any, assigned to BOS and BOL */
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color eos[2]; /* colors, if any, assigned to EOS and EOL */
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size_t size; /* Current NFA size; differs from nstates as
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* it also counts the number of states in
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* children of this NFA. */
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struct vars *v; /* simplifies compile error reporting */
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struct nfa *parent; /* parent NFA, if any */
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};
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/*
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* definitions for compacted NFA
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*
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* The main space savings in a compacted NFA is from making the arcs as small
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* as possible. We store only the transition color and next-state number for
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* each arc. The list of out arcs for each state is an array beginning at
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* cnfa.states[statenumber], and terminated by a dummy carc struct with
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* co == COLORLESS.
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*
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* The non-dummy carc structs are of two types: plain arcs and LACON arcs.
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* Plain arcs just store the transition color number as "co". LACON arcs
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* store the lookahead constraint number plus cnfa.ncolors as "co". LACON
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* arcs can be distinguished from plain by testing for co >= cnfa.ncolors.
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*/
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struct carc
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{
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color co; /* COLORLESS is list terminator */
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int to; /* next-state number */
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};
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struct cnfa
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{
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int nstates; /* number of states */
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int ncolors; /* number of colors (max color in use + 1) */
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int flags;
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#define HASLACONS 01 /* uses lookahead constraints */
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int pre; /* setup state number */
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int post; /* teardown state number */
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color bos[2]; /* colors, if any, assigned to BOS and BOL */
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color eos[2]; /* colors, if any, assigned to EOS and EOL */
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char *stflags; /* vector of per-state flags bytes */
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#define CNFA_NOPROGRESS 01 /* flag bit for a no-progress state */
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struct carc **states; /* vector of pointers to outarc lists */
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/* states[n] are pointers into a single malloc'd array of arcs */
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struct carc *arcs; /* the area for the lists */
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};
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#define ZAPCNFA(cnfa) ((cnfa).nstates = 0)
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#define NULLCNFA(cnfa) ((cnfa).nstates == 0)
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/*
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* Used to limit the maximum NFA size to something sane. [Tcl Bug 1810264]
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*/
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#ifndef REG_MAX_STATES
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#define REG_MAX_STATES 100000
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#endif
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/*
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* subexpression tree
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*
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* "op" is one of:
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* '=' plain regex without interesting substructure (implemented as DFA)
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* 'b' back-reference (has no substructure either)
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* '(' capture node: captures the match of its single child
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* '.' concatenation: matches a match for left, then a match for right
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* '|' alternation: matches a match for left or a match for right
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* '*' iteration: matches some number of matches of its single child
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*
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* Note: the right child of an alternation must be another alternation or
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* NULL; hence, an N-way branch requires N alternation nodes, not N-1 as you
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* might expect. This could stand to be changed. Actually I'd rather see
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* a single alternation node with N children, but that will take revising
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* the representation of struct subre.
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*
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* Note: when a backref is directly quantified, we stick the min/max counts
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* into the backref rather than plastering an iteration node on top. This is
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* for efficiency: there is no need to search for possible division points.
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*/
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struct subre
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{
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char op; /* see type codes above */
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char flags;
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#define LONGER 01 /* prefers longer match */
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#define SHORTER 02 /* prefers shorter match */
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#define MIXED 04 /* mixed preference below */
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#define CAP 010 /* capturing parens below */
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#define BACKR 020 /* back reference below */
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#define INUSE 0100 /* in use in final tree */
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#define LOCAL 03 /* bits which may not propagate up */
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#define LMIX(f) ((f)<<2) /* LONGER -> MIXED */
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#define SMIX(f) ((f)<<1) /* SHORTER -> MIXED */
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#define UP(f) (((f)&~LOCAL) | (LMIX(f) & SMIX(f) & MIXED))
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#define MESSY(f) ((f)&(MIXED|CAP|BACKR))
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#define PREF(f) ((f)&LOCAL)
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#define PREF2(f1, f2) ((PREF(f1) != 0) ? PREF(f1) : PREF(f2))
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#define COMBINE(f1, f2) (UP((f1)|(f2)) | PREF2(f1, f2))
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short id; /* ID of subre (1..ntree-1) */
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int subno; /* subexpression number (for 'b' and '(') */
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short min; /* min repetitions for iteration or backref */
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short max; /* max repetitions for iteration or backref */
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struct subre *left; /* left child, if any (also freelist chain) */
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struct subre *right; /* right child, if any */
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struct state *begin; /* outarcs from here... */
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struct state *end; /* ...ending in inarcs here */
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struct cnfa cnfa; /* compacted NFA, if any */
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struct subre *chain; /* for bookkeeping and error cleanup */
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};
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/*
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* table of function pointers for generic manipulation functions
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* A regex_t's re_fns points to one of these.
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*/
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struct fns
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{
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void FUNCPTR(free, (regex_t *));
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};
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/*
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* the insides of a regex_t, hidden behind a void *
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*/
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struct guts
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{
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int magic;
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#define GUTSMAGIC 0xfed9
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int cflags; /* copy of compile flags */
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long info; /* copy of re_info */
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size_t nsub; /* copy of re_nsub */
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struct subre *tree;
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struct cnfa search; /* for fast preliminary search */
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int ntree; /* number of subre's, less one */
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struct colormap cmap;
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int FUNCPTR(compare, (const chr *, const chr *, size_t));
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struct subre *lacons; /* lookahead-constraint vector */
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int nlacons; /* size of lacons */
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};
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