1334 lines
32 KiB
C
1334 lines
32 KiB
C
/*
|
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* TclRegComp and TclRegExec -- TclRegSub is elsewhere
|
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*
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* Copyright (c) 1986 by University of Toronto.
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* Written by Henry Spencer. Not derived from licensed software.
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*
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* Permission is granted to anyone to use this software for any
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* purpose on any computer system, and to redistribute it freely,
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* subject to the following restrictions:
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*
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* 1. The author is not responsible for the consequences of use of
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* this software, no matter how awful, even if they arise
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* from defects in it.
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*
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* 2. The origin of this software must not be misrepresented, either
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* by explicit claim or by omission.
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*
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* 3. Altered versions must be plainly marked as such, and must not
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* be misrepresented as being the original software.
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*
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* Beware that some of this code is subtly aware of the way operator
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* precedence is structured in regular expressions. Serious changes in
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* regular-expression syntax might require a total rethink.
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*
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* *** NOTE: this code has been altered slightly for use in Tcl: ***
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* *** 1. Use ckalloc and ckfree instead of malloc and free. ***
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* *** 2. Add extra argument to regexp to specify the real ***
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* *** start of the string separately from the start of the ***
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* *** current search. This is needed to search for multiple ***
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* *** matches within a string. ***
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* *** 3. Names have been changed, e.g. from regcomp to ***
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* *** TclRegComp, to avoid clashes with other ***
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* *** regexp implementations used by applications. ***
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* *** 4. Added errMsg declaration and TclRegError procedure ***
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* *** 5. Various lint-like things, such as casting arguments ***
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* *** in procedure calls. ***
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*
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* *** NOTE: This code has been altered for use in MT-Sturdy Tcl ***
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* *** 1. All use of static variables has been changed to access ***
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* *** fields of a structure. ***
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* *** 2. This in addition to changes to TclRegError makes the ***
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* *** code multi-thread safe. ***
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*
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* SCCS: @(#) regexp.c 1.13 97/04/29 17:49:17
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*/
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#include "tclInt.h"
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#include "tclPort.h"
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/*
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* The variable below is set to NULL before invoking regexp functions
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* and checked after those functions. If an error occurred then TclRegError
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* will set the variable to point to a (static) error message. This
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* mechanism unfortunately does not support multi-threading, but the
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* procedures TclRegError and TclGetRegError can be modified to use
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* thread-specific storage for the variable and thereby make the code
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* thread-safe.
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*/
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static char *errMsg = NULL;
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/*
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* The "internal use only" fields in regexp.h are present to pass info from
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* compile to execute that permits the execute phase to run lots faster on
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* simple cases. They are:
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*
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* regstart char that must begin a match; '\0' if none obvious
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* reganch is the match anchored (at beginning-of-line only)?
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* regmust string (pointer into program) that match must include, or NULL
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* regmlen length of regmust string
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*
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* Regstart and reganch permit very fast decisions on suitable starting points
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* for a match, cutting down the work a lot. Regmust permits fast rejection
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* of lines that cannot possibly match. The regmust tests are costly enough
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* that TclRegComp() supplies a regmust only if the r.e. contains something
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* potentially expensive (at present, the only such thing detected is * or +
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* at the start of the r.e., which can involve a lot of backup). Regmlen is
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* supplied because the test in TclRegExec() needs it and TclRegComp() is
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* computing it anyway.
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*/
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/*
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* Structure for regexp "program". This is essentially a linear encoding
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* of a nondeterministic finite-state machine (aka syntax charts or
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* "railroad normal form" in parsing technology). Each node is an opcode
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* plus a "next" pointer, possibly plus an operand. "Next" pointers of
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* all nodes except BRANCH implement concatenation; a "next" pointer with
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* a BRANCH on both ends of it is connecting two alternatives. (Here we
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* have one of the subtle syntax dependencies: an individual BRANCH (as
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* opposed to a collection of them) is never concatenated with anything
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* because of operator precedence.) The operand of some types of node is
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* a literal string; for others, it is a node leading into a sub-FSM. In
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* particular, the operand of a BRANCH node is the first node of the branch.
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* (NB this is *not* a tree structure: the tail of the branch connects
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* to the thing following the set of BRANCHes.) The opcodes are:
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*/
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/* definition number opnd? meaning */
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#define END 0 /* no End of program. */
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#define BOL 1 /* no Match "" at beginning of line. */
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#define EOL 2 /* no Match "" at end of line. */
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#define ANY 3 /* no Match any one character. */
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#define ANYOF 4 /* str Match any character in this string. */
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#define ANYBUT 5 /* str Match any character not in this string. */
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#define BRANCH 6 /* node Match this alternative, or the next... */
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#define BACK 7 /* no Match "", "next" ptr points backward. */
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#define EXACTLY 8 /* str Match this string. */
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#define NOTHING 9 /* no Match empty string. */
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#define STAR 10 /* node Match this (simple) thing 0 or more times. */
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#define PLUS 11 /* node Match this (simple) thing 1 or more times. */
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#define OPEN 20 /* no Mark this point in input as start of #n. */
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/* OPEN+1 is number 1, etc. */
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#define CLOSE (OPEN+NSUBEXP) /* no Analogous to OPEN. */
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/*
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* Opcode notes:
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*
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* BRANCH The set of branches constituting a single choice are hooked
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* together with their "next" pointers, since precedence prevents
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* anything being concatenated to any individual branch. The
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* "next" pointer of the last BRANCH in a choice points to the
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* thing following the whole choice. This is also where the
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* final "next" pointer of each individual branch points; each
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* branch starts with the operand node of a BRANCH node.
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*
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* BACK Normal "next" pointers all implicitly point forward; BACK
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* exists to make loop structures possible.
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*
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* STAR,PLUS '?', and complex '*' and '+', are implemented as circular
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* BRANCH structures using BACK. Simple cases (one character
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* per match) are implemented with STAR and PLUS for speed
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* and to minimize recursive plunges.
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*
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* OPEN,CLOSE ...are numbered at compile time.
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*/
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/*
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* A node is one char of opcode followed by two chars of "next" pointer.
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* "Next" pointers are stored as two 8-bit pieces, high order first. The
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* value is a positive offset from the opcode of the node containing it.
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* An operand, if any, simply follows the node. (Note that much of the
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* code generation knows about this implicit relationship.)
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*
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* Using two bytes for the "next" pointer is vast overkill for most things,
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* but allows patterns to get big without disasters.
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*/
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#define OP(p) (*(p))
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#define NEXT(p) (((*((p)+1)&0377)<<8) + (*((p)+2)&0377))
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#define OPERAND(p) ((p) + 3)
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/*
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* See regmagic.h for one further detail of program structure.
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*/
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/*
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* Utility definitions.
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*/
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#ifndef CHARBITS
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#define UCHARAT(p) ((int)*(unsigned char *)(p))
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#else
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#define UCHARAT(p) ((int)*(p)&CHARBITS)
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#endif
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#define FAIL(m) { TclRegError(m); return(NULL); }
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#define ISMULT(c) ((c) == '*' || (c) == '+' || (c) == '?')
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#define META "^$.[()|?+*\\"
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/*
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* Flags to be passed up and down.
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*/
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#define HASWIDTH 01 /* Known never to match null string. */
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#define SIMPLE 02 /* Simple enough to be STAR/PLUS operand. */
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#define SPSTART 04 /* Starts with * or +. */
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#define WORST 0 /* Worst case. */
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/*
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* Global work variables for TclRegComp().
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*/
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struct regcomp_state {
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char *regparse; /* Input-scan pointer. */
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int regnpar; /* () count. */
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char *regcode; /* Code-emit pointer; ®dummy = don't. */
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long regsize; /* Code size. */
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};
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static char regdummy;
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/*
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* The first byte of the regexp internal "program" is actually this magic
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* number; the start node begins in the second byte.
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*/
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#define MAGIC 0234
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/*
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* Forward declarations for TclRegComp()'s friends.
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*/
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static char * reg _ANSI_ARGS_((int paren, int *flagp,
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struct regcomp_state *rcstate));
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static char * regatom _ANSI_ARGS_((int *flagp,
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struct regcomp_state *rcstate));
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static char * regbranch _ANSI_ARGS_((int *flagp,
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struct regcomp_state *rcstate));
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static void regc _ANSI_ARGS_((int b,
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struct regcomp_state *rcstate));
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static void reginsert _ANSI_ARGS_((int op, char *opnd,
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struct regcomp_state *rcstate));
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static char * regnext _ANSI_ARGS_((char *p));
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static char * regnode _ANSI_ARGS_((int op,
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struct regcomp_state *rcstate));
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static void regoptail _ANSI_ARGS_((char *p, char *val));
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static char * regpiece _ANSI_ARGS_((int *flagp,
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struct regcomp_state *rcstate));
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static void regtail _ANSI_ARGS_((char *p, char *val));
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#ifdef STRCSPN
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static int strcspn _ANSI_ARGS_((char *s1, char *s2));
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#endif
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/*
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- TclRegComp - compile a regular expression into internal code
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*
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* We can't allocate space until we know how big the compiled form will be,
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* but we can't compile it (and thus know how big it is) until we've got a
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* place to put the code. So we cheat: we compile it twice, once with code
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* generation turned off and size counting turned on, and once "for real".
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* This also means that we don't allocate space until we are sure that the
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* thing really will compile successfully, and we never have to move the
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* code and thus invalidate pointers into it. (Note that it has to be in
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* one piece because free() must be able to free it all.)
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*
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* Beware that the optimization-preparation code in here knows about some
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* of the structure of the compiled regexp.
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*/
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regexp *
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TclRegComp(exp)
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char *exp;
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{
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register regexp *r;
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register char *scan;
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register char *longest;
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register int len;
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int flags;
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struct regcomp_state state;
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struct regcomp_state *rcstate= &state;
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if (exp == NULL)
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FAIL("NULL argument");
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/* First pass: determine size, legality. */
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rcstate->regparse = exp;
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rcstate->regnpar = 1;
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rcstate->regsize = 0L;
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rcstate->regcode = ®dummy;
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regc(MAGIC, rcstate);
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if (reg(0, &flags, rcstate) == NULL)
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return(NULL);
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/* Small enough for pointer-storage convention? */
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if (rcstate->regsize >= 32767L) /* Probably could be 65535L. */
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FAIL("regexp too big");
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/* Allocate space. */
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r = (regexp *)ckalloc(sizeof(regexp) + (unsigned)rcstate->regsize);
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if (r == NULL)
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FAIL("out of space");
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/* Second pass: emit code. */
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rcstate->regparse = exp;
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rcstate->regnpar = 1;
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rcstate->regcode = r->program;
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regc(MAGIC, rcstate);
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if (reg(0, &flags, rcstate) == NULL)
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return(NULL);
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/* Dig out information for optimizations. */
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r->regstart = '\0'; /* Worst-case defaults. */
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r->reganch = 0;
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r->regmust = NULL;
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r->regmlen = 0;
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scan = r->program+1; /* First BRANCH. */
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if (OP(regnext(scan)) == END) { /* Only one top-level choice. */
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scan = OPERAND(scan);
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/* Starting-point info. */
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if (OP(scan) == EXACTLY)
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r->regstart = *OPERAND(scan);
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else if (OP(scan) == BOL)
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r->reganch++;
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/*
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* If there's something expensive in the r.e., find the
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* longest literal string that must appear and make it the
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* regmust. Resolve ties in favor of later strings, since
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* the regstart check works with the beginning of the r.e.
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* and avoiding duplication strengthens checking. Not a
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* strong reason, but sufficient in the absence of others.
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*/
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if (flags&SPSTART) {
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longest = NULL;
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len = 0;
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for (; scan != NULL; scan = regnext(scan))
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if (OP(scan) == EXACTLY && ((int) strlen(OPERAND(scan))) >= len) {
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longest = OPERAND(scan);
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len = strlen(OPERAND(scan));
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}
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r->regmust = longest;
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r->regmlen = len;
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}
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}
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return(r);
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}
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/*
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- reg - regular expression, i.e. main body or parenthesized thing
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*
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* Caller must absorb opening parenthesis.
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*
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* Combining parenthesis handling with the base level of regular expression
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* is a trifle forced, but the need to tie the tails of the branches to what
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* follows makes it hard to avoid.
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*/
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static char *
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reg(paren, flagp, rcstate)
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int paren; /* Parenthesized? */
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int *flagp;
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struct regcomp_state *rcstate;
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{
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register char *ret;
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register char *br;
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register char *ender;
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register int parno = 0;
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int flags;
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*flagp = HASWIDTH; /* Tentatively. */
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/* Make an OPEN node, if parenthesized. */
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if (paren) {
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if (rcstate->regnpar >= NSUBEXP)
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FAIL("too many ()");
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parno = rcstate->regnpar;
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rcstate->regnpar++;
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ret = regnode(OPEN+parno,rcstate);
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} else
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ret = NULL;
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||
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/* Pick up the branches, linking them together. */
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br = regbranch(&flags,rcstate);
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if (br == NULL)
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return(NULL);
|
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if (ret != NULL)
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regtail(ret, br); /* OPEN -> first. */
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else
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ret = br;
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if (!(flags&HASWIDTH))
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*flagp &= ~HASWIDTH;
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*flagp |= flags&SPSTART;
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while (*rcstate->regparse == '|') {
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rcstate->regparse++;
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br = regbranch(&flags,rcstate);
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if (br == NULL)
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||
return(NULL);
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regtail(ret, br); /* BRANCH -> BRANCH. */
|
||
if (!(flags&HASWIDTH))
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*flagp &= ~HASWIDTH;
|
||
*flagp |= flags&SPSTART;
|
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}
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||
|
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/* Make a closing node, and hook it on the end. */
|
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ender = regnode((paren) ? CLOSE+parno : END,rcstate);
|
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regtail(ret, ender);
|
||
|
||
/* Hook the tails of the branches to the closing node. */
|
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for (br = ret; br != NULL; br = regnext(br))
|
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regoptail(br, ender);
|
||
|
||
/* Check for proper termination. */
|
||
if (paren && *rcstate->regparse++ != ')') {
|
||
FAIL("unmatched ()");
|
||
} else if (!paren && *rcstate->regparse != '\0') {
|
||
if (*rcstate->regparse == ')') {
|
||
FAIL("unmatched ()");
|
||
} else
|
||
FAIL("junk on end"); /* "Can't happen". */
|
||
/* NOTREACHED */
|
||
}
|
||
|
||
return(ret);
|
||
}
|
||
|
||
/*
|
||
- regbranch - one alternative of an | operator
|
||
*
|
||
* Implements the concatenation operator.
|
||
*/
|
||
static char *
|
||
regbranch(flagp, rcstate)
|
||
int *flagp;
|
||
struct regcomp_state *rcstate;
|
||
{
|
||
register char *ret;
|
||
register char *chain;
|
||
register char *latest;
|
||
int flags;
|
||
|
||
*flagp = WORST; /* Tentatively. */
|
||
|
||
ret = regnode(BRANCH,rcstate);
|
||
chain = NULL;
|
||
while (*rcstate->regparse != '\0' && *rcstate->regparse != '|' &&
|
||
*rcstate->regparse != ')') {
|
||
latest = regpiece(&flags, rcstate);
|
||
if (latest == NULL)
|
||
return(NULL);
|
||
*flagp |= flags&HASWIDTH;
|
||
if (chain == NULL) /* First piece. */
|
||
*flagp |= flags&SPSTART;
|
||
else
|
||
regtail(chain, latest);
|
||
chain = latest;
|
||
}
|
||
if (chain == NULL) /* Loop ran zero times. */
|
||
(void) regnode(NOTHING,rcstate);
|
||
|
||
return(ret);
|
||
}
|
||
|
||
/*
|
||
- regpiece - something followed by possible [*+?]
|
||
*
|
||
* Note that the branching code sequences used for ? and the general cases
|
||
* of * and + are somewhat optimized: they use the same NOTHING node as
|
||
* both the endmarker for their branch list and the body of the last branch.
|
||
* It might seem that this node could be dispensed with entirely, but the
|
||
* endmarker role is not redundant.
|
||
*/
|
||
static char *
|
||
regpiece(flagp, rcstate)
|
||
int *flagp;
|
||
struct regcomp_state *rcstate;
|
||
{
|
||
register char *ret;
|
||
register char op;
|
||
register char *next;
|
||
int flags;
|
||
|
||
ret = regatom(&flags,rcstate);
|
||
if (ret == NULL)
|
||
return(NULL);
|
||
|
||
op = *rcstate->regparse;
|
||
if (!ISMULT(op)) {
|
||
*flagp = flags;
|
||
return(ret);
|
||
}
|
||
|
||
if (!(flags&HASWIDTH) && op != '?')
|
||
FAIL("*+ operand could be empty");
|
||
*flagp = (op != '+') ? (WORST|SPSTART) : (WORST|HASWIDTH);
|
||
|
||
if (op == '*' && (flags&SIMPLE))
|
||
reginsert(STAR, ret, rcstate);
|
||
else if (op == '*') {
|
||
/* Emit x* as (x&|), where & means "self". */
|
||
reginsert(BRANCH, ret, rcstate); /* Either x */
|
||
regoptail(ret, regnode(BACK,rcstate)); /* and loop */
|
||
regoptail(ret, ret); /* back */
|
||
regtail(ret, regnode(BRANCH,rcstate)); /* or */
|
||
regtail(ret, regnode(NOTHING,rcstate)); /* null. */
|
||
} else if (op == '+' && (flags&SIMPLE))
|
||
reginsert(PLUS, ret, rcstate);
|
||
else if (op == '+') {
|
||
/* Emit x+ as x(&|), where & means "self". */
|
||
next = regnode(BRANCH,rcstate); /* Either */
|
||
regtail(ret, next);
|
||
regtail(regnode(BACK,rcstate), ret); /* loop back */
|
||
regtail(next, regnode(BRANCH,rcstate)); /* or */
|
||
regtail(ret, regnode(NOTHING,rcstate)); /* null. */
|
||
} else if (op == '?') {
|
||
/* Emit x? as (x|) */
|
||
reginsert(BRANCH, ret, rcstate); /* Either x */
|
||
regtail(ret, regnode(BRANCH,rcstate)); /* or */
|
||
next = regnode(NOTHING,rcstate); /* null. */
|
||
regtail(ret, next);
|
||
regoptail(ret, next);
|
||
}
|
||
rcstate->regparse++;
|
||
if (ISMULT(*rcstate->regparse))
|
||
FAIL("nested *?+");
|
||
|
||
return(ret);
|
||
}
|
||
|
||
/*
|
||
- regatom - the lowest level
|
||
*
|
||
* Optimization: gobbles an entire sequence of ordinary characters so that
|
||
* it can turn them into a single node, which is smaller to store and
|
||
* faster to run. Backslashed characters are exceptions, each becoming a
|
||
* separate node; the code is simpler that way and it's not worth fixing.
|
||
*/
|
||
static char *
|
||
regatom(flagp, rcstate)
|
||
int *flagp;
|
||
struct regcomp_state *rcstate;
|
||
{
|
||
register char *ret;
|
||
int flags;
|
||
|
||
*flagp = WORST; /* Tentatively. */
|
||
|
||
switch (*rcstate->regparse++) {
|
||
case '^':
|
||
ret = regnode(BOL,rcstate);
|
||
break;
|
||
case '$':
|
||
ret = regnode(EOL,rcstate);
|
||
break;
|
||
case '.':
|
||
ret = regnode(ANY,rcstate);
|
||
*flagp |= HASWIDTH|SIMPLE;
|
||
break;
|
||
case '[': {
|
||
register int clss;
|
||
register int classend;
|
||
|
||
if (*rcstate->regparse == '^') { /* Complement of range. */
|
||
ret = regnode(ANYBUT,rcstate);
|
||
rcstate->regparse++;
|
||
} else
|
||
ret = regnode(ANYOF,rcstate);
|
||
if (*rcstate->regparse == ']' || *rcstate->regparse == '-')
|
||
regc(*rcstate->regparse++,rcstate);
|
||
while (*rcstate->regparse != '\0' && *rcstate->regparse != ']') {
|
||
if (*rcstate->regparse == '-') {
|
||
rcstate->regparse++;
|
||
if (*rcstate->regparse == ']' || *rcstate->regparse == '\0')
|
||
regc('-',rcstate);
|
||
else {
|
||
clss = UCHARAT(rcstate->regparse-2)+1;
|
||
classend = UCHARAT(rcstate->regparse);
|
||
if (clss > classend+1)
|
||
FAIL("invalid [] range");
|
||
for (; clss <= classend; clss++)
|
||
regc((char)clss,rcstate);
|
||
rcstate->regparse++;
|
||
}
|
||
} else
|
||
regc(*rcstate->regparse++,rcstate);
|
||
}
|
||
regc('\0',rcstate);
|
||
if (*rcstate->regparse != ']')
|
||
FAIL("unmatched []");
|
||
rcstate->regparse++;
|
||
*flagp |= HASWIDTH|SIMPLE;
|
||
}
|
||
break;
|
||
case '(':
|
||
ret = reg(1, &flags, rcstate);
|
||
if (ret == NULL)
|
||
return(NULL);
|
||
*flagp |= flags&(HASWIDTH|SPSTART);
|
||
break;
|
||
case '\0':
|
||
case '|':
|
||
case ')':
|
||
FAIL("internal urp"); /* Supposed to be caught earlier. */
|
||
/* NOTREACHED */
|
||
case '?':
|
||
case '+':
|
||
case '*':
|
||
FAIL("?+* follows nothing");
|
||
/* NOTREACHED */
|
||
case '\\':
|
||
if (*rcstate->regparse == '\0')
|
||
FAIL("trailing \\");
|
||
ret = regnode(EXACTLY,rcstate);
|
||
regc(*rcstate->regparse++,rcstate);
|
||
regc('\0',rcstate);
|
||
*flagp |= HASWIDTH|SIMPLE;
|
||
break;
|
||
default: {
|
||
register int len;
|
||
register char ender;
|
||
|
||
rcstate->regparse--;
|
||
len = strcspn(rcstate->regparse, META);
|
||
if (len <= 0)
|
||
FAIL("internal disaster");
|
||
ender = *(rcstate->regparse+len);
|
||
if (len > 1 && ISMULT(ender))
|
||
len--; /* Back off clear of ?+* operand. */
|
||
*flagp |= HASWIDTH;
|
||
if (len == 1)
|
||
*flagp |= SIMPLE;
|
||
ret = regnode(EXACTLY,rcstate);
|
||
while (len > 0) {
|
||
regc(*rcstate->regparse++,rcstate);
|
||
len--;
|
||
}
|
||
regc('\0',rcstate);
|
||
}
|
||
break;
|
||
}
|
||
|
||
return(ret);
|
||
}
|
||
|
||
/*
|
||
- regnode - emit a node
|
||
*/
|
||
static char * /* Location. */
|
||
regnode(op, rcstate)
|
||
int op;
|
||
struct regcomp_state *rcstate;
|
||
{
|
||
register char *ret;
|
||
register char *ptr;
|
||
|
||
ret = rcstate->regcode;
|
||
if (ret == ®dummy) {
|
||
rcstate->regsize += 3;
|
||
return(ret);
|
||
}
|
||
|
||
ptr = ret;
|
||
*ptr++ = (char)op;
|
||
*ptr++ = '\0'; /* Null "next" pointer. */
|
||
*ptr++ = '\0';
|
||
rcstate->regcode = ptr;
|
||
|
||
return(ret);
|
||
}
|
||
|
||
/*
|
||
- regc - emit (if appropriate) a byte of code
|
||
*/
|
||
static void
|
||
regc(b, rcstate)
|
||
int b;
|
||
struct regcomp_state *rcstate;
|
||
{
|
||
if (rcstate->regcode != ®dummy)
|
||
*rcstate->regcode++ = (char)b;
|
||
else
|
||
rcstate->regsize++;
|
||
}
|
||
|
||
/*
|
||
- reginsert - insert an operator in front of already-emitted operand
|
||
*
|
||
* Means relocating the operand.
|
||
*/
|
||
static void
|
||
reginsert(op, opnd, rcstate)
|
||
int op;
|
||
char *opnd;
|
||
struct regcomp_state *rcstate;
|
||
{
|
||
register char *src;
|
||
register char *dst;
|
||
register char *place;
|
||
|
||
if (rcstate->regcode == ®dummy) {
|
||
rcstate->regsize += 3;
|
||
return;
|
||
}
|
||
|
||
src = rcstate->regcode;
|
||
rcstate->regcode += 3;
|
||
dst = rcstate->regcode;
|
||
while (src > opnd)
|
||
*--dst = *--src;
|
||
|
||
place = opnd; /* Op node, where operand used to be. */
|
||
*place++ = (char)op;
|
||
*place++ = '\0';
|
||
*place = '\0';
|
||
}
|
||
|
||
/*
|
||
- regtail - set the next-pointer at the end of a node chain
|
||
*/
|
||
static void
|
||
regtail(p, val)
|
||
char *p;
|
||
char *val;
|
||
{
|
||
register char *scan;
|
||
register char *temp;
|
||
register int offset;
|
||
|
||
if (p == ®dummy)
|
||
return;
|
||
|
||
/* Find last node. */
|
||
scan = p;
|
||
for (;;) {
|
||
temp = regnext(scan);
|
||
if (temp == NULL)
|
||
break;
|
||
scan = temp;
|
||
}
|
||
|
||
if (OP(scan) == BACK)
|
||
offset = scan - val;
|
||
else
|
||
offset = val - scan;
|
||
*(scan+1) = (char)((offset>>8)&0377);
|
||
*(scan+2) = (char)(offset&0377);
|
||
}
|
||
|
||
/*
|
||
- regoptail - regtail on operand of first argument; nop if operandless
|
||
*/
|
||
static void
|
||
regoptail(p, val)
|
||
char *p;
|
||
char *val;
|
||
{
|
||
/* "Operandless" and "op != BRANCH" are synonymous in practice. */
|
||
if (p == NULL || p == ®dummy || OP(p) != BRANCH)
|
||
return;
|
||
regtail(OPERAND(p), val);
|
||
}
|
||
|
||
/*
|
||
* TclRegExec and friends
|
||
*/
|
||
|
||
/*
|
||
* Global work variables for TclRegExec().
|
||
*/
|
||
struct regexec_state {
|
||
char *reginput; /* String-input pointer. */
|
||
char *regbol; /* Beginning of input, for ^ check. */
|
||
char **regstartp; /* Pointer to startp array. */
|
||
char **regendp; /* Ditto for endp. */
|
||
};
|
||
|
||
/*
|
||
* Forwards.
|
||
*/
|
||
static int regtry _ANSI_ARGS_((regexp *prog, char *string,
|
||
struct regexec_state *restate));
|
||
static int regmatch _ANSI_ARGS_((char *prog,
|
||
struct regexec_state *restate));
|
||
static int regrepeat _ANSI_ARGS_((char *p,
|
||
struct regexec_state *restate));
|
||
|
||
#ifdef DEBUG
|
||
int regnarrate = 0;
|
||
void regdump _ANSI_ARGS_((regexp *r));
|
||
static char *regprop _ANSI_ARGS_((char *op));
|
||
#endif
|
||
|
||
/*
|
||
- TclRegExec - match a regexp against a string
|
||
*/
|
||
int
|
||
TclRegExec(prog, string, start)
|
||
register regexp *prog;
|
||
register char *string;
|
||
char *start;
|
||
{
|
||
register char *s;
|
||
struct regexec_state state;
|
||
struct regexec_state *restate= &state;
|
||
|
||
/* Be paranoid... */
|
||
if (prog == NULL || string == NULL) {
|
||
TclRegError("NULL parameter");
|
||
return(0);
|
||
}
|
||
|
||
/* Check validity of program. */
|
||
if (UCHARAT(prog->program) != MAGIC) {
|
||
TclRegError("corrupted program");
|
||
return(0);
|
||
}
|
||
|
||
/* If there is a "must appear" string, look for it. */
|
||
if (prog->regmust != NULL) {
|
||
s = string;
|
||
while ((s = strchr(s, prog->regmust[0])) != NULL) {
|
||
if (strncmp(s, prog->regmust, (size_t) prog->regmlen)
|
||
== 0)
|
||
break; /* Found it. */
|
||
s++;
|
||
}
|
||
if (s == NULL) /* Not present. */
|
||
return(0);
|
||
}
|
||
|
||
/* Mark beginning of line for ^ . */
|
||
restate->regbol = start;
|
||
|
||
/* Simplest case: anchored match need be tried only once. */
|
||
if (prog->reganch)
|
||
return(regtry(prog, string, restate));
|
||
|
||
/* Messy cases: unanchored match. */
|
||
s = string;
|
||
if (prog->regstart != '\0')
|
||
/* We know what char it must start with. */
|
||
while ((s = strchr(s, prog->regstart)) != NULL) {
|
||
if (regtry(prog, s, restate))
|
||
return(1);
|
||
s++;
|
||
}
|
||
else
|
||
/* We don't -- general case. */
|
||
do {
|
||
if (regtry(prog, s, restate))
|
||
return(1);
|
||
} while (*s++ != '\0');
|
||
|
||
/* Failure. */
|
||
return(0);
|
||
}
|
||
|
||
/*
|
||
- regtry - try match at specific point
|
||
*/
|
||
static int /* 0 failure, 1 success */
|
||
regtry(prog, string, restate)
|
||
regexp *prog;
|
||
char *string;
|
||
struct regexec_state *restate;
|
||
{
|
||
register int i;
|
||
register char **sp;
|
||
register char **ep;
|
||
|
||
restate->reginput = string;
|
||
restate->regstartp = prog->startp;
|
||
restate->regendp = prog->endp;
|
||
|
||
sp = prog->startp;
|
||
ep = prog->endp;
|
||
for (i = NSUBEXP; i > 0; i--) {
|
||
*sp++ = NULL;
|
||
*ep++ = NULL;
|
||
}
|
||
if (regmatch(prog->program + 1,restate)) {
|
||
prog->startp[0] = string;
|
||
prog->endp[0] = restate->reginput;
|
||
return(1);
|
||
} else
|
||
return(0);
|
||
}
|
||
|
||
/*
|
||
- regmatch - main matching routine
|
||
*
|
||
* Conceptually the strategy is simple: check to see whether the current
|
||
* node matches, call self recursively to see whether the rest matches,
|
||
* and then act accordingly. In practice we make some effort to avoid
|
||
* recursion, in particular by going through "ordinary" nodes (that don't
|
||
* need to know whether the rest of the match failed) by a loop instead of
|
||
* by recursion.
|
||
*/
|
||
static int /* 0 failure, 1 success */
|
||
regmatch(prog, restate)
|
||
char *prog;
|
||
struct regexec_state *restate;
|
||
{
|
||
register char *scan; /* Current node. */
|
||
char *next; /* Next node. */
|
||
|
||
scan = prog;
|
||
#ifdef DEBUG
|
||
if (scan != NULL && regnarrate)
|
||
fprintf(stderr, "%s(\n", regprop(scan));
|
||
#endif
|
||
while (scan != NULL) {
|
||
#ifdef DEBUG
|
||
if (regnarrate)
|
||
fprintf(stderr, "%s...\n", regprop(scan));
|
||
#endif
|
||
next = regnext(scan);
|
||
|
||
switch (OP(scan)) {
|
||
case BOL:
|
||
if (restate->reginput != restate->regbol) {
|
||
return 0;
|
||
}
|
||
break;
|
||
case EOL:
|
||
if (*restate->reginput != '\0') {
|
||
return 0;
|
||
}
|
||
break;
|
||
case ANY:
|
||
if (*restate->reginput == '\0') {
|
||
return 0;
|
||
}
|
||
restate->reginput++;
|
||
break;
|
||
case EXACTLY: {
|
||
register int len;
|
||
register char *opnd;
|
||
|
||
opnd = OPERAND(scan);
|
||
/* Inline the first character, for speed. */
|
||
if (*opnd != *restate->reginput) {
|
||
return 0 ;
|
||
}
|
||
len = strlen(opnd);
|
||
if (len > 1 && strncmp(opnd, restate->reginput, (size_t) len)
|
||
!= 0) {
|
||
return 0;
|
||
}
|
||
restate->reginput += len;
|
||
break;
|
||
}
|
||
case ANYOF:
|
||
if (*restate->reginput == '\0'
|
||
|| strchr(OPERAND(scan), *restate->reginput) == NULL) {
|
||
return 0;
|
||
}
|
||
restate->reginput++;
|
||
break;
|
||
case ANYBUT:
|
||
if (*restate->reginput == '\0'
|
||
|| strchr(OPERAND(scan), *restate->reginput) != NULL) {
|
||
return 0;
|
||
}
|
||
restate->reginput++;
|
||
break;
|
||
case NOTHING:
|
||
break;
|
||
case BACK:
|
||
break;
|
||
case OPEN+1:
|
||
case OPEN+2:
|
||
case OPEN+3:
|
||
case OPEN+4:
|
||
case OPEN+5:
|
||
case OPEN+6:
|
||
case OPEN+7:
|
||
case OPEN+8:
|
||
case OPEN+9: {
|
||
register int no;
|
||
register char *save;
|
||
|
||
doOpen:
|
||
no = OP(scan) - OPEN;
|
||
save = restate->reginput;
|
||
|
||
if (regmatch(next,restate)) {
|
||
/*
|
||
* Don't set startp if some later invocation of the
|
||
* same parentheses already has.
|
||
*/
|
||
if (restate->regstartp[no] == NULL) {
|
||
restate->regstartp[no] = save;
|
||
}
|
||
return 1;
|
||
} else {
|
||
return 0;
|
||
}
|
||
}
|
||
case CLOSE+1:
|
||
case CLOSE+2:
|
||
case CLOSE+3:
|
||
case CLOSE+4:
|
||
case CLOSE+5:
|
||
case CLOSE+6:
|
||
case CLOSE+7:
|
||
case CLOSE+8:
|
||
case CLOSE+9: {
|
||
register int no;
|
||
register char *save;
|
||
|
||
doClose:
|
||
no = OP(scan) - CLOSE;
|
||
save = restate->reginput;
|
||
|
||
if (regmatch(next,restate)) {
|
||
/*
|
||
* Don't set endp if some later
|
||
* invocation of the same parentheses
|
||
* already has.
|
||
*/
|
||
if (restate->regendp[no] == NULL)
|
||
restate->regendp[no] = save;
|
||
return 1;
|
||
} else {
|
||
return 0;
|
||
}
|
||
}
|
||
case BRANCH: {
|
||
register char *save;
|
||
|
||
if (OP(next) != BRANCH) { /* No choice. */
|
||
next = OPERAND(scan); /* Avoid recursion. */
|
||
} else {
|
||
do {
|
||
save = restate->reginput;
|
||
if (regmatch(OPERAND(scan),restate))
|
||
return(1);
|
||
restate->reginput = save;
|
||
scan = regnext(scan);
|
||
} while (scan != NULL && OP(scan) == BRANCH);
|
||
return 0;
|
||
}
|
||
break;
|
||
}
|
||
case STAR:
|
||
case PLUS: {
|
||
register char nextch;
|
||
register int no;
|
||
register char *save;
|
||
register int min;
|
||
|
||
/*
|
||
* Lookahead to avoid useless match attempts
|
||
* when we know what character comes next.
|
||
*/
|
||
nextch = '\0';
|
||
if (OP(next) == EXACTLY)
|
||
nextch = *OPERAND(next);
|
||
min = (OP(scan) == STAR) ? 0 : 1;
|
||
save = restate->reginput;
|
||
no = regrepeat(OPERAND(scan),restate);
|
||
while (no >= min) {
|
||
/* If it could work, try it. */
|
||
if (nextch == '\0' || *restate->reginput == nextch)
|
||
if (regmatch(next,restate))
|
||
return(1);
|
||
/* Couldn't or didn't -- back up. */
|
||
no--;
|
||
restate->reginput = save + no;
|
||
}
|
||
return(0);
|
||
}
|
||
case END:
|
||
return(1); /* Success! */
|
||
default:
|
||
if (OP(scan) > OPEN && OP(scan) < OPEN+NSUBEXP) {
|
||
goto doOpen;
|
||
} else if (OP(scan) > CLOSE && OP(scan) < CLOSE+NSUBEXP) {
|
||
goto doClose;
|
||
}
|
||
TclRegError("memory corruption");
|
||
return 0;
|
||
}
|
||
|
||
scan = next;
|
||
}
|
||
|
||
/*
|
||
* We get here only if there's trouble -- normally "case END" is
|
||
* the terminating point.
|
||
*/
|
||
TclRegError("corrupted pointers");
|
||
return(0);
|
||
}
|
||
|
||
/*
|
||
- regrepeat - repeatedly match something simple, report how many
|
||
*/
|
||
static int
|
||
regrepeat(p, restate)
|
||
char *p;
|
||
struct regexec_state *restate;
|
||
{
|
||
register int count = 0;
|
||
register char *scan;
|
||
register char *opnd;
|
||
|
||
scan = restate->reginput;
|
||
opnd = OPERAND(p);
|
||
switch (OP(p)) {
|
||
case ANY:
|
||
count = strlen(scan);
|
||
scan += count;
|
||
break;
|
||
case EXACTLY:
|
||
while (*opnd == *scan) {
|
||
count++;
|
||
scan++;
|
||
}
|
||
break;
|
||
case ANYOF:
|
||
while (*scan != '\0' && strchr(opnd, *scan) != NULL) {
|
||
count++;
|
||
scan++;
|
||
}
|
||
break;
|
||
case ANYBUT:
|
||
while (*scan != '\0' && strchr(opnd, *scan) == NULL) {
|
||
count++;
|
||
scan++;
|
||
}
|
||
break;
|
||
default: /* Oh dear. Called inappropriately. */
|
||
TclRegError("internal foulup");
|
||
count = 0; /* Best compromise. */
|
||
break;
|
||
}
|
||
restate->reginput = scan;
|
||
|
||
return(count);
|
||
}
|
||
|
||
/*
|
||
- regnext - dig the "next" pointer out of a node
|
||
*/
|
||
static char *
|
||
regnext(p)
|
||
register char *p;
|
||
{
|
||
register int offset;
|
||
|
||
if (p == ®dummy)
|
||
return(NULL);
|
||
|
||
offset = NEXT(p);
|
||
if (offset == 0)
|
||
return(NULL);
|
||
|
||
if (OP(p) == BACK)
|
||
return(p-offset);
|
||
else
|
||
return(p+offset);
|
||
}
|
||
|
||
#ifdef DEBUG
|
||
|
||
static char *regprop();
|
||
|
||
/*
|
||
- regdump - dump a regexp onto stdout in vaguely comprehensible form
|
||
*/
|
||
void
|
||
regdump(r)
|
||
regexp *r;
|
||
{
|
||
register char *s;
|
||
register char op = EXACTLY; /* Arbitrary non-END op. */
|
||
register char *next;
|
||
|
||
|
||
s = r->program + 1;
|
||
while (op != END) { /* While that wasn't END last time... */
|
||
op = OP(s);
|
||
printf("%2d%s", s-r->program, regprop(s)); /* Where, what. */
|
||
next = regnext(s);
|
||
if (next == NULL) /* Next ptr. */
|
||
printf("(0)");
|
||
else
|
||
printf("(%d)", (s-r->program)+(next-s));
|
||
s += 3;
|
||
if (op == ANYOF || op == ANYBUT || op == EXACTLY) {
|
||
/* Literal string, where present. */
|
||
while (*s != '\0') {
|
||
putchar(*s);
|
||
s++;
|
||
}
|
||
s++;
|
||
}
|
||
putchar('\n');
|
||
}
|
||
|
||
/* Header fields of interest. */
|
||
if (r->regstart != '\0')
|
||
printf("start `%c' ", r->regstart);
|
||
if (r->reganch)
|
||
printf("anchored ");
|
||
if (r->regmust != NULL)
|
||
printf("must have \"%s\"", r->regmust);
|
||
printf("\n");
|
||
}
|
||
|
||
/*
|
||
- regprop - printable representation of opcode
|
||
*/
|
||
static char *
|
||
regprop(op)
|
||
char *op;
|
||
{
|
||
register char *p;
|
||
static char buf[50];
|
||
|
||
(void) strcpy(buf, ":");
|
||
|
||
switch (OP(op)) {
|
||
case BOL:
|
||
p = "BOL";
|
||
break;
|
||
case EOL:
|
||
p = "EOL";
|
||
break;
|
||
case ANY:
|
||
p = "ANY";
|
||
break;
|
||
case ANYOF:
|
||
p = "ANYOF";
|
||
break;
|
||
case ANYBUT:
|
||
p = "ANYBUT";
|
||
break;
|
||
case BRANCH:
|
||
p = "BRANCH";
|
||
break;
|
||
case EXACTLY:
|
||
p = "EXACTLY";
|
||
break;
|
||
case NOTHING:
|
||
p = "NOTHING";
|
||
break;
|
||
case BACK:
|
||
p = "BACK";
|
||
break;
|
||
case END:
|
||
p = "END";
|
||
break;
|
||
case OPEN+1:
|
||
case OPEN+2:
|
||
case OPEN+3:
|
||
case OPEN+4:
|
||
case OPEN+5:
|
||
case OPEN+6:
|
||
case OPEN+7:
|
||
case OPEN+8:
|
||
case OPEN+9:
|
||
sprintf(buf+strlen(buf), "OPEN%d", OP(op)-OPEN);
|
||
p = NULL;
|
||
break;
|
||
case CLOSE+1:
|
||
case CLOSE+2:
|
||
case CLOSE+3:
|
||
case CLOSE+4:
|
||
case CLOSE+5:
|
||
case CLOSE+6:
|
||
case CLOSE+7:
|
||
case CLOSE+8:
|
||
case CLOSE+9:
|
||
sprintf(buf+strlen(buf), "CLOSE%d", OP(op)-CLOSE);
|
||
p = NULL;
|
||
break;
|
||
case STAR:
|
||
p = "STAR";
|
||
break;
|
||
case PLUS:
|
||
p = "PLUS";
|
||
break;
|
||
default:
|
||
if (OP(op) > OPEN && OP(op) < OPEN+NSUBEXP) {
|
||
sprintf(buf+strlen(buf), "OPEN%d", OP(op)-OPEN);
|
||
p = NULL;
|
||
break;
|
||
} else if (OP(op) > CLOSE && OP(op) < CLOSE+NSUBEXP) {
|
||
sprintf(buf+strlen(buf), "CLOSE%d", OP(op)-CLOSE);
|
||
p = NULL;
|
||
} else {
|
||
TclRegError("corrupted opcode");
|
||
}
|
||
break;
|
||
}
|
||
if (p != NULL)
|
||
(void) strcat(buf, p);
|
||
return(buf);
|
||
}
|
||
#endif
|
||
|
||
/*
|
||
* The following is provided for those people who do not have strcspn() in
|
||
* their C libraries. They should get off their butts and do something
|
||
* about it; at least one public-domain implementation of those (highly
|
||
* useful) string routines has been published on Usenet.
|
||
*/
|
||
#ifdef STRCSPN
|
||
/*
|
||
* strcspn - find length of initial segment of s1 consisting entirely
|
||
* of characters not from s2
|
||
*/
|
||
|
||
static int
|
||
strcspn(s1, s2)
|
||
char *s1;
|
||
char *s2;
|
||
{
|
||
register char *scan1;
|
||
register char *scan2;
|
||
register int count;
|
||
|
||
count = 0;
|
||
for (scan1 = s1; *scan1 != '\0'; scan1++) {
|
||
for (scan2 = s2; *scan2 != '\0';) /* ++ moved down. */
|
||
if (*scan1 == *scan2++)
|
||
return(count);
|
||
count++;
|
||
}
|
||
return(count);
|
||
}
|
||
#endif
|
||
|
||
/*
|
||
*----------------------------------------------------------------------
|
||
*
|
||
* TclRegError --
|
||
*
|
||
* This procedure is invoked by the regexp code when an error
|
||
* occurs. It saves the error message so it can be seen by the
|
||
* code that called Spencer's code.
|
||
*
|
||
* Results:
|
||
* None.
|
||
*
|
||
* Side effects:
|
||
* The value of "string" is saved in "errMsg".
|
||
*
|
||
*----------------------------------------------------------------------
|
||
*/
|
||
|
||
void
|
||
TclRegError(string)
|
||
char *string; /* Error message. */
|
||
{
|
||
errMsg = string;
|
||
}
|
||
|
||
char *
|
||
TclGetRegError()
|
||
{
|
||
return errMsg;
|
||
}
|