/* 

 * tclRegexp.c --

 *

 *	This file contains the public interfaces to the Tcl regular

 *	expression mechanism.

 *

 * Copyright (c) 1998 by Sun Microsystems, Inc.

 * Copyright (c) 1998-1999 by Scriptics Corporation.

 * Portions Copyright (c) 2007-2008 Nokia Corporation and/or its subsidiaries. All rights reserved.  

 *

 * See the file "license.terms" for information on usage and redistribution

 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.

 *

 * RCS: @(#) $Id: tclRegexp.c,v 1.14.4.2 2006/04/07 01:14:28 hobbs Exp $

 */

#include "tclInt.h"

#include "tclPort.h"

#include "tclRegexp.h"

#if defined(__SYMBIAN32__) && defined(__WINSCW__)

#include "tclSymbianGlobals.h"

#define dataKey getdataKey(6)

#endif 

/*

 *----------------------------------------------------------------------

 * The routines in this file use Henry Spencer's regular expression

 * package contained in the following additional source files:

 *

 *	regc_color.c	regc_cvec.c	regc_lex.c

 *	regc_nfa.c	regcomp.c	regcustom.h

 *	rege_dfa.c	regerror.c	regerrs.h

 *	regex.h		regexec.c	regfree.c

 *	regfronts.c	regguts.h

 *

 * Copyright (c) 1998 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.

 *

 * *** NOTE: this code has been altered slightly for use in Tcl: ***

 * *** 1. Names have been changed, e.g. from re_comp to		 ***

 * ***    TclRegComp, to avoid clashes with other 		 ***

 * ***    regexp implementations used by applications. 		 ***

 */

/*

 * Thread local storage used to maintain a per-thread cache of compiled

 * regular expressions.

 */

#define NUM_REGEXPS 30

typedef struct ThreadSpecificData {

    int initialized;		/* Set to 1 when the module is initialized. */

    char *patterns[NUM_REGEXPS];/* Strings corresponding to compiled

				 * regular expression patterns.	 NULL

				 * means that this slot isn't used.

				 * Malloc-ed. */

    int patLengths[NUM_REGEXPS];/* Number of non-null characters in

				 * corresponding entry in patterns.

				 * -1 means entry isn't used. */

    struct TclRegexp *regexps[NUM_REGEXPS];

				/* Compiled forms of above strings.  Also

				 * malloc-ed, or NULL if not in use yet. */

} ThreadSpecificData;

#if !defined(__SYMBIAN32__) || !defined(__WINSCW__)

static Tcl_ThreadDataKey dataKey;

#endif

/*

 * Declarations for functions used only in this file.

 */

static TclRegexp *	CompileRegexp _ANSI_ARGS_((Tcl_Interp *interp,

			    CONST char *pattern, int length, int flags));

static void		DupRegexpInternalRep _ANSI_ARGS_((Tcl_Obj *srcPtr,

			    Tcl_Obj *copyPtr));

static void		FinalizeRegexp _ANSI_ARGS_((ClientData clientData));

static void		FreeRegexp _ANSI_ARGS_((TclRegexp *regexpPtr));

static void		FreeRegexpInternalRep _ANSI_ARGS_((Tcl_Obj *objPtr));

static int		RegExpExecUniChar _ANSI_ARGS_((Tcl_Interp *interp,

			    Tcl_RegExp re, CONST Tcl_UniChar *uniString,

			    int numChars, int nmatches, int flags));

static int		SetRegexpFromAny _ANSI_ARGS_((Tcl_Interp *interp,

			    Tcl_Obj *objPtr));

/*

 * The regular expression Tcl object type.  This serves as a cache

 * of the compiled form of the regular expression.

 */

static Tcl_ObjType tclRegexpType = {

    "regexp",				/* name */

    FreeRegexpInternalRep,		/* freeIntRepProc */

    DupRegexpInternalRep,		/* dupIntRepProc */

    NULL,				/* updateStringProc */

    SetRegexpFromAny			/* setFromAnyProc */

};

/*

 *----------------------------------------------------------------------

 *

 * Tcl_RegExpCompile --

 *

 *	Compile a regular expression into a form suitable for fast

 *	matching.  This procedure is DEPRECATED in favor of the

 *	object version of the command.

 *

 * Results:

 *	The return value is a pointer to the compiled form of string,

 *	suitable for passing to Tcl_RegExpExec.  This compiled form

 *	is only valid up until the next call to this procedure, so

 *	don't keep these around for a long time!  If an error occurred

 *	while compiling the pattern, then NULL is returned and an error

 *	message is left in the interp's result.

 *

 * Side effects:

 *	Updates the cache of compiled regexps.

 *

 *----------------------------------------------------------------------

 */

EXPORT_C Tcl_RegExp

Tcl_RegExpCompile(interp, string)

    Tcl_Interp *interp;		/* For use in error reporting and

				 * to access the interp regexp cache. */

    CONST char *string;		/* String for which to produce

				 * compiled regular expression. */

{

    return (Tcl_RegExp) CompileRegexp(interp, string, (int) strlen(string),

	    REG_ADVANCED);

}

/*

 *----------------------------------------------------------------------

 *

 * Tcl_RegExpExec --

 *

 *	Execute the regular expression matcher using a compiled form

 *	of a regular expression and save information about any match

 *	that is found.

 *

 * Results:

 *	If an error occurs during the matching operation then -1

 *	is returned and the interp's result contains an error message.

 *	Otherwise the return value is 1 if a matching range is

 *	found and 0 if there is no matching range.

 *

 * Side effects:

 *	None.

 *

 *----------------------------------------------------------------------

 */

EXPORT_C int

Tcl_RegExpExec(interp, re, string, start)

    Tcl_Interp *interp;		/* Interpreter to use for error reporting. */

    Tcl_RegExp re;		/* Compiled regular expression;  must have

				 * been returned by previous call to

				 * Tcl_GetRegExpFromObj. */

    CONST char *string;		/* String against which to match re. */

    CONST char *start;		/* If string is part of a larger string,

				 * this identifies beginning of larger

				 * string, so that "^" won't match. */

{

    int flags, result, numChars;

    TclRegexp *regexp = (TclRegexp *)re;

    Tcl_DString ds;

    CONST Tcl_UniChar *ustr;

    /*

     * If the starting point is offset from the beginning of the buffer,

     * then we need to tell the regexp engine not to match "^".

     */

    if (string > start) {

	flags = REG_NOTBOL;

    } else {

	flags = 0;

    }

    /*

     * Remember the string for use by Tcl_RegExpRange().

     */

    regexp->string = string;

    regexp->objPtr = NULL;

    /*

     * Convert the string to Unicode and perform the match.

     */

    Tcl_DStringInit(&ds);

    ustr = Tcl_UtfToUniCharDString(string, -1, &ds);

    numChars = Tcl_DStringLength(&ds) / sizeof(Tcl_UniChar);

    result = RegExpExecUniChar(interp, re, ustr, numChars,

	    -1 /* nmatches */, flags);

    Tcl_DStringFree(&ds);

    return result;

}

/*

 *---------------------------------------------------------------------------

 *

 * Tcl_RegExpRange --

 *

 *	Returns pointers describing the range of a regular expression match,

 *	or one of the subranges within the match.

 *

 * Results:

 *	The variables at *startPtr and *endPtr are modified to hold the

 *	addresses of the endpoints of the range given by index.  If the

 *	specified range doesn't exist then NULLs are returned.

 *

 * Side effects:

 *	None.

 *

 *---------------------------------------------------------------------------

 */

EXPORT_C void

Tcl_RegExpRange(re, index, startPtr, endPtr)

    Tcl_RegExp re;		/* Compiled regular expression that has

				 * been passed to Tcl_RegExpExec. */

    int index;			/* 0 means give the range of the entire

				 * match, > 0 means give the range of

				 * a matching subrange. */

    CONST char **startPtr;	/* Store address of first character in

				 * (sub-) range here. */

    CONST char **endPtr;	/* Store address of character just after last

				 * in (sub-) range here. */

{

    TclRegexp *regexpPtr = (TclRegexp *) re;

    CONST char *string;

    if ((size_t) index > regexpPtr->re.re_nsub) {

	*startPtr = *endPtr = NULL;

    } else if (regexpPtr->matches[index].rm_so < 0) {

	*startPtr = *endPtr = NULL;

    } else {

	if (regexpPtr->objPtr) {

	    string = Tcl_GetString(regexpPtr->objPtr);

	} else {

	    string = regexpPtr->string;

	}

	*startPtr = Tcl_UtfAtIndex(string, regexpPtr->matches[index].rm_so);

	*endPtr = Tcl_UtfAtIndex(string, regexpPtr->matches[index].rm_eo);

    }

}

/*

 *---------------------------------------------------------------------------

 *

 * RegExpExecUniChar --

 *

 *	Execute the regular expression matcher using a compiled form of a

 *	regular expression and save information about any match that is

 *	found.

 *

 * Results:

 *	If an error occurs during the matching operation then -1 is

 *	returned and an error message is left in interp's result.

 *	Otherwise the return value is 1 if a matching range was found or

 *	0 if there was no matching range.

 *

 * Side effects:

 *	None.

 *

 *----------------------------------------------------------------------

 */

static int

RegExpExecUniChar(interp, re, wString, numChars, nmatches, flags)

    Tcl_Interp *interp;		/* Interpreter to use for error reporting. */

    Tcl_RegExp re;		/* Compiled regular expression; returned by

				 * a previous call to Tcl_GetRegExpFromObj */

    CONST Tcl_UniChar *wString;	/* String against which to match re. */

    int numChars;		/* Length of Tcl_UniChar string (must

				 * be >= 0). */

    int nmatches;		/* How many subexpression matches (counting

				 * the whole match as subexpression 0) are

				 * of interest.  -1 means "don't know". */

    int flags;			/* Regular expression flags. */

{

    int status;

    TclRegexp *regexpPtr = (TclRegexp *) re;

    size_t last = regexpPtr->re.re_nsub + 1;

    size_t nm = last;

    if (nmatches >= 0 && (size_t) nmatches < nm) {

	nm = (size_t) nmatches;

    }

    status = TclReExec(&regexpPtr->re, wString, (size_t) numChars,

	    &regexpPtr->details, nm, regexpPtr->matches, flags);

    /*

     * Check for errors.

     */

    if (status != REG_OKAY) {

	if (status == REG_NOMATCH) {

	    return 0;

	}

	if (interp != NULL) {

	    TclRegError(interp, "error while matching regular expression: ",

		    status);

	}

	return -1;

    }

    return 1;

}

/*

 *---------------------------------------------------------------------------

 *

 * TclRegExpRangeUniChar --

 *

 *	Returns pointers describing the range of a regular expression match,

 *	or one of the subranges within the match, or the hypothetical range

 *	represented by the rm_extend field of the rm_detail_t.

 *

 * Results:

 *	The variables at *startPtr and *endPtr are modified to hold the

 *	offsets of the endpoints of the range given by index.  If the

 *	specified range doesn't exist then -1s are supplied.

 *

 * Side effects:

 *	None.

 *

 *---------------------------------------------------------------------------

 */

void

TclRegExpRangeUniChar(re, index, startPtr, endPtr)

    Tcl_RegExp re;		/* Compiled regular expression that has

				 * been passed to Tcl_RegExpExec. */

    int index;			/* 0 means give the range of the entire

				 * match, > 0 means give the range of

				 * a matching subrange, -1 means the

				 * range of the rm_extend field. */

    int *startPtr;		/* Store address of first character in

				 * (sub-) range here. */

    int *endPtr;		/* Store address of character just after last

				 * in (sub-) range here. */

{

    TclRegexp *regexpPtr = (TclRegexp *) re;

    if ((regexpPtr->flags&REG_EXPECT) && index == -1) {

	*startPtr = regexpPtr->details.rm_extend.rm_so;

	*endPtr = regexpPtr->details.rm_extend.rm_eo;

    } else if ((size_t) index > regexpPtr->re.re_nsub) {

	*startPtr = -1;

	*endPtr = -1;

    } else {

	*startPtr = regexpPtr->matches[index].rm_so;

	*endPtr = regexpPtr->matches[index].rm_eo;

    }

}

/*

 *----------------------------------------------------------------------

 *

 * Tcl_RegExpMatch --

 *

 *	See if a string matches a regular expression.

 *

 * Results:

 *	If an error occurs during the matching operation then -1

 *	is returned and the interp's result contains an error message.

 *	Otherwise the return value is 1 if "string" matches "pattern"

 *	and 0 otherwise.

 *

 * Side effects:

 *	None.

 *

 *----------------------------------------------------------------------

 */

EXPORT_C int

Tcl_RegExpMatch(interp, string, pattern)

    Tcl_Interp *interp;		/* Used for error reporting. May be NULL. */

    CONST char *string;		/* String. */

    CONST char *pattern;	/* Regular expression to match against

				 * string. */

{

    Tcl_RegExp re;

    re = Tcl_RegExpCompile(interp, pattern);

    if (re == NULL) {

	return -1;

    }

    return Tcl_RegExpExec(interp, re, string, string);

}

/*

 *----------------------------------------------------------------------

 *

 * Tcl_RegExpExecObj --

 *

 *	Execute a precompiled regexp against the given object.

 *

 * Results:

 *	If an error occurs during the matching operation then -1

 *	is returned and the interp's result contains an error message.

 *	Otherwise the return value is 1 if "string" matches "pattern"

 *	and 0 otherwise.

 *

 * Side effects:

 *	Converts the object to a Unicode object.

 *

 *----------------------------------------------------------------------

 */

EXPORT_C int

Tcl_RegExpExecObj(interp, re, objPtr, offset, nmatches, flags)

    Tcl_Interp *interp;		/* Interpreter to use for error reporting. */

    Tcl_RegExp re;		/* Compiled regular expression;  must have

				 * been returned by previous call to

				 * Tcl_GetRegExpFromObj. */

    Tcl_Obj *objPtr;		/* String against which to match re. */

    int offset;			/* Character index that marks where matching

				 * should begin. */

    int nmatches;		/* How many subexpression matches (counting

				 * the whole match as subexpression 0) are

				 * of interest.  -1 means all of them. */

    int flags;			/* Regular expression execution flags. */

{

    TclRegexp *regexpPtr = (TclRegexp *) re;

    Tcl_UniChar *udata;

    int length;

    /*

     * Save the target object so we can extract strings from it later.

     */

    regexpPtr->string = NULL;

    regexpPtr->objPtr = objPtr;

    udata = Tcl_GetUnicodeFromObj(objPtr, &length);

    if (offset > length) {

	offset = length;

    }

    udata += offset;

    length -= offset;

    return RegExpExecUniChar(interp, re, udata, length, nmatches, flags);

}

/*

 *----------------------------------------------------------------------

 *

 * Tcl_RegExpMatchObj --

 *

 *	See if an object matches a regular expression.

 *

 * Results:

 *	If an error occurs during the matching operation then -1

 *	is returned and the interp's result contains an error message.

 *	Otherwise the return value is 1 if "string" matches "pattern"

 *	and 0 otherwise.

 *

 * Side effects:

 *	Changes the internal rep of the pattern and string objects.

 *

 *----------------------------------------------------------------------

 */

EXPORT_C int

Tcl_RegExpMatchObj(interp, stringObj, patternObj)

    Tcl_Interp *interp;		/* Used for error reporting. May be NULL. */

    Tcl_Obj *stringObj;		/* Object containing the String to search. */

    Tcl_Obj *patternObj;	/* Regular expression to match against

				 * string. */

{

    Tcl_RegExp re;

    re = Tcl_GetRegExpFromObj(interp, patternObj,

	    TCL_REG_ADVANCED | TCL_REG_NOSUB);

    if (re == NULL) {

	return -1;

    }

    return Tcl_RegExpExecObj(interp, re, stringObj, 0 /* offset */,

	    0 /* nmatches */, 0 /* flags */);

}

/*

 *----------------------------------------------------------------------

 *

 * Tcl_RegExpGetInfo --

 *

 *	Retrieve information about the current match.

 *

 * Results:

 *	None.

 *

 * Side effects:

 *	None.

 *

 *----------------------------------------------------------------------

 */

EXPORT_C void

Tcl_RegExpGetInfo(regexp, infoPtr)

    Tcl_RegExp regexp;		/* Pattern from which to get subexpressions. */

    Tcl_RegExpInfo *infoPtr;	/* Match information is stored here.  */

{

    TclRegexp *regexpPtr = (TclRegexp *) regexp;

    infoPtr->nsubs = regexpPtr->re.re_nsub;

    infoPtr->matches = (Tcl_RegExpIndices *) regexpPtr->matches;

    infoPtr->extendStart = regexpPtr->details.rm_extend.rm_so;

}

/*

 *----------------------------------------------------------------------

 *

 * Tcl_GetRegExpFromObj --

 *

 *	Compile a regular expression into a form suitable for fast

 *	matching.  This procedure caches the result in a Tcl_Obj.

 *

 * Results:

 *	The return value is a pointer to the compiled form of string,

 *	suitable for passing to Tcl_RegExpExec.  If an error occurred

 *	while compiling the pattern, then NULL is returned and an error

 *	message is left in the interp's result.

 *

 * Side effects:

 *	Updates the native rep of the Tcl_Obj.

 *

 *----------------------------------------------------------------------

 */

EXPORT_C Tcl_RegExp

Tcl_GetRegExpFromObj(interp, objPtr, flags)

    Tcl_Interp *interp;		/* For use in error reporting, and to access

				 * the interp regexp cache. */

    Tcl_Obj *objPtr;		/* Object whose string rep contains regular

				 * expression pattern.  Internal rep will be

				 * changed to compiled form of this regular

				 * expression. */

    int flags;			/* Regular expression compilation flags. */

{

    int length;

    Tcl_ObjType *typePtr;

    TclRegexp *regexpPtr;

    char *pattern;

    typePtr = objPtr->typePtr;

    regexpPtr = (TclRegexp *) objPtr->internalRep.otherValuePtr;

    if ((typePtr != &tclRegexpType) || (regexpPtr->flags != flags)) {

	pattern = Tcl_GetStringFromObj(objPtr, &length);

	regexpPtr = CompileRegexp(interp, pattern, length, flags);

	if (regexpPtr == NULL) {

	    return NULL;

	}

	/*

	 * Add a reference to the regexp so it will persist even if it is

	 * pushed out of the current thread's regexp cache.  This reference

	 * will be removed when the object's internal rep is freed.

	 */

	regexpPtr->refCount++;

	/*

	 * Free the old representation and set our type.

	 */

	if ((typePtr != NULL) && (typePtr->freeIntRepProc != NULL)) {

	    (*typePtr->freeIntRepProc)(objPtr);

	}

	objPtr->internalRep.otherValuePtr = (VOID *) regexpPtr;

	objPtr->typePtr = &tclRegexpType;

    }

    return (Tcl_RegExp) regexpPtr;

}

/*

 *----------------------------------------------------------------------

 *

 * TclRegAbout --

 *

 *	Return information about a compiled regular expression.

 *

 * Results:

 *	The return value is -1 for failure, 0 for success, although at

 *	the moment there's nothing that could fail.  On success, a list

 *	is left in the interp's result:  first element is the subexpression

 *	count, second is a list of re_info bit names.

 *

 * Side effects:

 *	None.

 *

 *----------------------------------------------------------------------

 */

int

TclRegAbout(interp, re)

    Tcl_Interp *interp;		/* For use in variable assignment. */

    Tcl_RegExp re;		/* The compiled regular expression. */

{

    TclRegexp *regexpPtr = (TclRegexp *)re;

    char buf[TCL_INTEGER_SPACE];

    static struct infoname {

	int bit;

	char *text;

    } infonames[] = {

	{REG_UBACKREF,		"REG_UBACKREF"},

	{REG_ULOOKAHEAD,	"REG_ULOOKAHEAD"},

	{REG_UBOUNDS,		"REG_UBOUNDS"},

	{REG_UBRACES,		"REG_UBRACES"},

	{REG_UBSALNUM,		"REG_UBSALNUM"},

	{REG_UPBOTCH,		"REG_UPBOTCH"},

	{REG_UBBS,		"REG_UBBS"},

	{REG_UNONPOSIX,		"REG_UNONPOSIX"},

	{REG_UUNSPEC,		"REG_UUNSPEC"},

	{REG_UUNPORT,		"REG_UUNPORT"},

	{REG_ULOCALE,		"REG_ULOCALE"},

	{REG_UEMPTYMATCH,	"REG_UEMPTYMATCH"},

	{REG_UIMPOSSIBLE,	"REG_UIMPOSSIBLE"},

	{REG_USHORTEST,		"REG_USHORTEST"},

	{0,			""}

    };

    struct infoname *inf;

    int n;

    Tcl_ResetResult(interp);

    sprintf(buf, "%u", (unsigned)(regexpPtr->re.re_nsub));

    Tcl_AppendElement(interp, buf);

    /*

     * Must count bits before generating list, because we must know

     * whether {} are needed before we start appending names.

     */

    n = 0;

    for (inf = infonames; inf->bit != 0; inf++) {

	if (regexpPtr->re.re_info&inf->bit) {

	    n++;

	}

    }

    if (n != 1) {

	Tcl_AppendResult(interp, " {", NULL);

    }

    for (inf = infonames; inf->bit != 0; inf++) {

	if (regexpPtr->re.re_info&inf->bit) {

	    Tcl_AppendElement(interp, inf->text);

	}

    }

    if (n != 1) {

	Tcl_AppendResult(interp, "}", NULL);

    }

    return 0;

}

/*

 *----------------------------------------------------------------------

 *

 * TclRegError --

 *

 *	Generate an error message based on the regexp status code.

 *

 * Results:

 *	Places an error in the interpreter.

 *

 * Side effects:

 *	Sets errorCode as well.

 *

 *----------------------------------------------------------------------

 */

void

TclRegError(interp, msg, status)

    Tcl_Interp *interp;		/* Interpreter for error reporting. */

    CONST char *msg;		/* Message to prepend to error. */

    int status;			/* Status code to report. */

{

    char buf[100];		/* ample in practice */

    char cbuf[100];		/* lots in practice */

    size_t n;

    char *p;

    Tcl_ResetResult(interp);

    n = TclReError(status, (regex_t *)NULL, buf, sizeof(buf));

    p = (n > sizeof(buf)) ? "..." : "";

    Tcl_AppendResult(interp, msg, buf, p, NULL);

    sprintf(cbuf, "%d", status);

    (VOID) TclReError(REG_ITOA, (regex_t *)NULL, cbuf, sizeof(cbuf));

    Tcl_SetErrorCode(interp, "REGEXP", cbuf, buf, NULL);

}

/*

 *----------------------------------------------------------------------

 *

 * FreeRegexpInternalRep --

 *

 *	Deallocate the storage associated with a regexp object's internal

 *	representation.

 *

 * Results:

 *	None.

 *

 * Side effects:

 *	Frees the compiled regular expression.

 *

 *----------------------------------------------------------------------

 */

static void

FreeRegexpInternalRep(objPtr)

    Tcl_Obj *objPtr;		/* Regexp object with internal rep to free. */

{

    TclRegexp *regexpRepPtr = (TclRegexp *) objPtr->internalRep.otherValuePtr;

    /*

     * If this is the last reference to the regexp, free it.

     */

    if (--(regexpRepPtr->refCount) <= 0) {

	FreeRegexp(regexpRepPtr);

    }

}

/*

 *----------------------------------------------------------------------

 *

 * DupRegexpInternalRep --

 *

 *	We copy the reference to the compiled regexp and bump its

 *	reference count.

 *

 * Results:

 *	None.

 *

 * Side effects:

 *	Increments the reference count of the regexp.

 *

 *----------------------------------------------------------------------

 */

static void

DupRegexpInternalRep(srcPtr, copyPtr)

    Tcl_Obj *srcPtr;		/* Object with internal rep to copy. */

    Tcl_Obj *copyPtr;		/* Object with internal rep to set. */

{

    TclRegexp *regexpPtr = (TclRegexp *) srcPtr->internalRep.otherValuePtr;

    regexpPtr->refCount++;

    copyPtr->internalRep.otherValuePtr = srcPtr->internalRep.otherValuePtr;

    copyPtr->typePtr = &tclRegexpType;

}

/*

 *----------------------------------------------------------------------

 *

 * SetRegexpFromAny --

 *

 *	Attempt to generate a compiled regular expression for the Tcl object

 *	"objPtr".

 *

 * Results:

 *	The return value is TCL_OK or TCL_ERROR. If an error occurs during

 *	conversion, an error message is left in the interpreter's result

 *	unless "interp" is NULL.

 *

 * Side effects:

 *	If no error occurs, a regular expression is stored as "objPtr"s

 *	internal representation.

 *

 *----------------------------------------------------------------------

 */

static int

SetRegexpFromAny(interp, objPtr)

    Tcl_Interp *interp;		/* Used for error reporting if not NULL. */

    Tcl_Obj *objPtr;		/* The object to convert. */

{

    if (Tcl_GetRegExpFromObj(interp, objPtr, REG_ADVANCED) == NULL) {

	return TCL_ERROR;

    }

    return TCL_OK;

}

/*

 *---------------------------------------------------------------------------

 *

 * CompileRegexp --

 *

 *	Attempt to compile the given regexp pattern.  If the compiled

 *	regular expression can be found in the per-thread cache, it

 *	will be used instead of compiling a new copy.

 *

 * Results:

 *	The return value is a pointer to a newly allocated TclRegexp

 *	that represents the compiled pattern, or NULL if the pattern

 *	could not be compiled.  If NULL is returned, an error message is

 *	left in the interp's result.

 *

 * Side effects:

 *	The thread-local regexp cache is updated and a new TclRegexp may

 *	be allocated.

 *

 *----------------------------------------------------------------------

 */

static TclRegexp *

CompileRegexp(interp, string, length, flags)

    Tcl_Interp *interp;		/* Used for error reporting if not NULL. */

    CONST char *string;		/* The regexp to compile (UTF-8). */

    int length;			/* The length of the string in bytes. */

    int flags;			/* Compilation flags. */

{

    TclRegexp *regexpPtr;

    CONST Tcl_UniChar *uniString;

    int numChars;

    Tcl_DString stringBuf;

    int status, i;

    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    if (!tsdPtr->initialized) {

	tsdPtr->initialized = 1;

	Tcl_CreateThreadExitHandler(FinalizeRegexp, NULL);

    }

    /*

     * This routine maintains a second-level regular expression cache in

     * addition to the per-object regexp cache.  The per-thread cache is needed

     * to handle the case where for various reasons the object is lost between

     * invocations of the regexp command, but the literal pattern is the same.

     */

    /*

     * Check the per-thread compiled regexp cache.  We can only reuse

     * a regexp if it has the same pattern and the same flags.

     */

    for (i = 0; (i < NUM_REGEXPS) && (tsdPtr->patterns[i] != NULL); i++) {

	if ((length == tsdPtr->patLengths[i])

		&& (tsdPtr->regexps[i]->flags == flags)

		&& (strcmp(string, tsdPtr->patterns[i]) == 0)) {

	    /*

	     * Move the matched pattern to the first slot in the

	     * cache and shift the other patterns down one position.

	     */

	    if (i != 0) {

		int j;

		char *cachedString;

		cachedString = tsdPtr->patterns[i];

		regexpPtr = tsdPtr->regexps[i];

		for (j = i-1; j >= 0; j--) {

		    tsdPtr->patterns[j+1] = tsdPtr->patterns[j];

		    tsdPtr->patLengths[j+1] = tsdPtr->patLengths[j];

		    tsdPtr->regexps[j+1] = tsdPtr->regexps[j];

		}

		tsdPtr->patterns[0] = cachedString;

		tsdPtr->patLengths[0] = length;

		tsdPtr->regexps[0] = regexpPtr;

	    }

	    return tsdPtr->regexps[0];

	}

    }

    /*

     * This is a new expression, so compile it and add it to the cache.

     */

    regexpPtr = (TclRegexp *) ckalloc(sizeof(TclRegexp));

    regexpPtr->objPtr = NULL;

    regexpPtr->string = NULL;

    regexpPtr->details.rm_extend.rm_so = -1;

    regexpPtr->details.rm_extend.rm_eo = -1;

    /*

     * Get the up-to-date string representation and map to unicode.

     */

    Tcl_DStringInit(&stringBuf);

    uniString = Tcl_UtfToUniCharDString(string, length, &stringBuf);

    numChars = Tcl_DStringLength(&stringBuf) / sizeof(Tcl_UniChar);

    /*

     * Compile the string and check for errors.

     */

    regexpPtr->flags = flags;

    status = TclReComp(&regexpPtr->re, uniString, (size_t) numChars, flags);

    Tcl_DStringFree(&stringBuf);

    if (status != REG_OKAY) {

	/*

	 * Clean up and report errors in the interpreter, if possible.

	 */

	ckfree((char *)regexpPtr);

	if (interp) {

	    TclRegError(interp,

		    "couldn't compile regular expression pattern: ",

		    status);

	}

	return NULL;

    }

    /*

     * Allocate enough space for all of the subexpressions, plus one

     * extra for the entire pattern.

     */

    regexpPtr->matches = (regmatch_t *) ckalloc(

	    sizeof(regmatch_t) * (regexpPtr->re.re_nsub + 1));

    /*

     * Initialize the refcount to one initially, since it is in the cache.

     */

    regexpPtr->refCount = 1;

    /*

     * Free the last regexp, if necessary, and make room at the head of the

     * list for the new regexp.

     */

    if (tsdPtr->patterns[NUM_REGEXPS-1] != NULL) {

	TclRegexp *oldRegexpPtr = tsdPtr->regexps[NUM_REGEXPS-1];

	if (--(oldRegexpPtr->refCount) <= 0) {

	    FreeRegexp(oldRegexpPtr);

	}

	ckfree(tsdPtr->patterns[NUM_REGEXPS-1]);

    }

    for (i = NUM_REGEXPS - 2; i >= 0; i--) {

	tsdPtr->patterns[i+1] = tsdPtr->patterns[i];

	tsdPtr->patLengths[i+1] = tsdPtr->patLengths[i];

	tsdPtr->regexps[i+1] = tsdPtr->regexps[i];

    }

    tsdPtr->patterns[0] = (char *) ckalloc((unsigned) (length+1));

    strcpy(tsdPtr->patterns[0], string);

    tsdPtr->patLengths[0] = length;

    tsdPtr->regexps[0] = regexpPtr;

    return regexpPtr;

}

/*

 *----------------------------------------------------------------------

 *

 * FreeRegexp --

 *

 *	Release the storage associated with a TclRegexp.

 *

 * Results:

 *	None.

 *

 * Side effects:

 *	None.

 *

 *----------------------------------------------------------------------

 */

static void

FreeRegexp(regexpPtr)

    TclRegexp *regexpPtr;	/* Compiled regular expression to free. */