static Tcl_NRPostProc	TryPostBody;
static Tcl_NRPostProc	TryPostFinal;
static Tcl_NRPostProc	TryPostHandler;
static int		UniCharIsAscii(int character);
static int		UniCharIsHexDigit(int character);

#if TCL_UTF_MAX == 3
static int		MemCmp(const void *s1, const void *s2, size_t n,
			    int flags);
static int		NumCodePointsUtf(const char *src, int length,
			    int *flagPtr);
static int		NumCodePointsUnicode(const Tcl_UniChar *src,
			    int length, int *flagPtr);
static int		UniCharNcmp(const Tcl_UniChar *ucs,
			    const Tcl_UniChar *uct, size_t numCp, int flags);
static int		UniCharNcasecmp(const Tcl_UniChar *ucs,
			    const Tcl_UniChar *uct, size_t numCp, int flags);
static int		UtfNcasecmp(const char *cs, const char *ct,
			    size_t numCp, int flags);
static int		UtfNcmp(const char *cs, const char *ct,
			    size_t numCp, int flags);
#endif

/*
 * Default set of characters to trim in [string trim] and friends. This is a
 * UTF-8 literal string containing all Unicode space characters [TIP #413]
 */

	"\xef\xbb\xbf" /* zero width no-break space (U+feff) */
;

#if TCL_UTF_MAX == 3
/*
 *---------------------------------------------------------------------------
 *
 * MemCmp --
 *
 *	Private wrapper for memcmp(). See C library documentation.
 *
 *---------------------------------------------------------------------------
 */

static int
MemCmp(const void *s1, const void *s2, size_t n, int flags)
{
    return memcmp(s1, s2, n);
}
#endif

#if TCL_UTF_MAX == 3
/*
 *---------------------------------------------------------------------------
 *
 * NumCodePointsUtf --
 *
 *	Like Tcl_NumUtfChars() but returns the number of code points.



 *
 * Results:
 *	As above.
 *
 * Side effects:
 *	None.
 *
 *---------------------------------------------------------------------------
 */

static int
NumCodePointsUtf(
    const char *src,		/* The UTF-8 string to measure. */
    int length,			/* The length of the string in bytes. */
    int *flagPtr)		/* Location to receive end flag. */
{
    Tcl_UniChar ch = 0;
    int i = 0;

    const char *endPtr = src + length - TCL_UTF_MAX;

    *flagPtr = 0;
    while (src < endPtr) {
	src += TclUtfToUniChar(src, &ch);
	if ((ch & 0xFC00) == 0xD800) {
	    if ((src < endPtr) && Tcl_UtfCharComplete(src, endPtr - src)) {
		int len = TclUtfToUniChar(src, &ch);

		if ((ch & 0xFC00) == 0xDC00) {

	    }
	}
	i++;
    }
    if (src < endPtr) {
	i += endPtr - src;
    } else if (i && ((ch & 0xFC00) == 0xD800)) {

	*flagPtr = 1;
    }
    return i;
}
#endif

#if TCL_UTF_MAX == 3
/*

 *----------------------------------------------------------------------
 */

static int
UtfNcmp(
    const char *cs,		/* UTF string to compare to ct. */
    const char *ct,		/* UTF string cs is compared to. */
    size_t numCp,		/* Number of code points to compare. */
    int flags)			/* Flags describing string ends. */
{
    Tcl_UniChar ch1 = 0, ch2 = 0;
    int uch1, uch2;

    while (numCp-- > 0) {

	cs += TclUtfToUniChar(cs, &ch1);
	ct += TclUtfToUniChar(ct, &ch2);

	uch1 = ch1;
	uch2 = ch2;

	if ((ch1 & 0xFC00) == 0xD800) {
	    if ((flags & 1) && (numCp == 0)) {
		/* String ends with high surrogate. */
	    } else {
		int len = TclUtfToUniChar(cs, &ch1);

		if ((ch1 & 0xFC00) == 0xDC00) {
		    uch1 = (((uch1&0x3FF)<<10) | (ch1&0x3FF)) + 0x10000;
		    cs += len;
		}
	    }
	}
	if ((ch2 & 0xFC00) == 0xD800) {
	    if ((flags & 2) && (numCp == 0)) {
		/* String ends with high surrogate. */
	    } else {
		int len = TclUtfToUniChar(ct, &ch2);

		if ((ch2 & 0xFC00) == 0xDC00) {
		    uch2 = (((uch2&0x3FF)<<10) | (ch2&0x3FF)) + 0x10000;
		    ct += len;
		}
	    }
	}

	if (uch1 != uch2) {
	    return (uch1 - uch2);
	}
    }

 *----------------------------------------------------------------------
 */

static int
UtfNcasecmp(
    const char *cs,		/* UTF string to compare to ct. */
    const char *ct,		/* UTF string cs is compared to. */
    size_t numCp,		/* Number of code points to compare. */
    int flags)			/* Flags describing string ends. */
{
    Tcl_UniChar ch1 = 0, ch2 = 0;
    int uch1, uch2;

    while (numCp-- > 0) {

	cs += TclUtfToUniChar(cs, &ch1);
	ct += TclUtfToUniChar(ct, &ch2);

	uch1 = ch1;
	uch2 = ch2;

	if ((ch1 & 0xFC00) == 0xD800) {
	    if ((flags & 1) && (numCp == 0)) {
		/* String ends with high surrogate. */
	    } else {
		int len = TclUtfToUniChar(cs, &ch1);

		if ((ch1 & 0xFC00) == 0xDC00) {
		    uch1 = (((uch1&0x3FF)<<10) | (ch1&0x3FF)) + 0x10000;
		    cs += len;
		}
	    }
	}
	if ((ch2 & 0xFC00) == 0xD800) {
	    if ((flags & 2) && (numCp == 0)) {
		/* String ends with high surrogate. */
	    } else {
		int len = TclUtfToUniChar(ct, &ch2);

		if ((ch2 & 0xFC00) == 0xDC00) {
		    uch2 = (((uch2&0x3FF)<<10) | (ch2&0x3FF)) + 0x10000;
		    ct += len;
		}
	    }
	}

	if (uch1 != uch2) {
	    uch1 = TclUCS4ToLower(uch1);
	    uch2 = TclUCS4ToLower(uch2);
	    if (uch1 != uch2) {

#if TCL_UTF_MAX == 3
/*
 *---------------------------------------------------------------------------
 *
 * NumCodePointsUnicode --
 *
 *	Returns the number of code points of a Tcl_UniChar array.




 *
 * Results:
 *	As above.
 *
 * Side effects:
 *	None.
 *
 *---------------------------------------------------------------------------
 */

static int
NumCodePointsUnicode(
    const Tcl_UniChar *src,	/* The array to measure. */
    int length,			/* The length of the array in elements. */
    int *flagPtr)		/* Location to receive end flag. */
{
    int i, n = 0;

    *flagPtr = 0;
    for (i = 0; i < length; i++, n++) {
	if ((src[i] & 0xFC00) == 0xD800) {
	    if (i + 1 >= length) {

		*flagPtr = 1;
	    }
	    if ((i + 1 < length) && ((src[i+1] & 0xFC00) == 0xDC00)) {
		i++;
	    }
	}
    }
    return n;

 *----------------------------------------------------------------------
 */

static int
UniCharNcmp(
    const Tcl_UniChar *ucs,	/* Unicode string to compare to uct. */
    const Tcl_UniChar *uct,	/* Unicode string ucs is compared to. */
    size_t numCp,		/* Number of code points to compare. */
    int flags)			/* Flags describing string ends. */
{
    int lcs, lct;

    for ( ; numCp != 0; numCp--, ucs++, uct++) {
	lcs = *ucs;
	lct = *uct;
	if ((lcs & 0xFC00) == 0xD800) {
	    if ((flags & 1) && (numCp == 1)) {
		/* String ends with high surrogate. */
	    } else if ((ucs[1] & 0xFC00) == 0xDC00) {
		lcs = (((lcs&0x3FF)<<10) | (ucs[1]&0x3FF)) + 0x10000;
		ucs++;
	    }
	}
	if ((lct & 0xFC00) == 0xD800) {
	    if ((flags & 2) && (numCp == 1)) {
		/* String ends with high surrogate. */
	    } else if ((uct[1] & 0xFC00) == 0xDC00) {
		lct = (((lct&0x3FF)<<10) | (uct[1]&0x3FF)) + 0x10000;
		uct++;
	    }
	}
	if (lcs != lct) {
	    return (lcs - lct);
	}

 *----------------------------------------------------------------------
 */

static int
UniCharNcasecmp(
    const Tcl_UniChar *ucs,	/* Unicode string to compare to uct. */
    const Tcl_UniChar *uct,	/* Unicode string ucs is compared to. */
    size_t numCp,		/* Number of code points to compare. */
    int flags)			/* Flags describing string ends. */
{
    int lcs, lct;

    for ( ; numCp != 0; numCp--, ucs++, uct++) {
	lcs = *ucs;
	lct = *uct;
	if ((lcs & 0xFC00) == 0xD800) {
	    if ((flags & 1) && (numCp == 1)) {
		/* String ends with high surrogate. */
	    } else if ((ucs[1] & 0xFC00) == 0xDC00) {
		lcs = (((lcs&0x3FF)<<10) | (ucs[1]&0x3FF)) + 0x10000;
		ucs++;
	    }
	}
	if ((lct & 0xFC00) == 0xD800) {
	    if ((flags & 2) && (numCp == 1)) {
		/* String ends with high surrogate. */
	    } else if ((uct[1] & 0xFC00) == 0xDC00) {
		lct = (((lct&0x3FF)<<10) | (uct[1]&0x3FF)) + 0x10000;
		uct++;
	    }
	}
	if (lcs != lct) {
	    lcs = TclUCS4ToLower(lcs);
	    lct = TclUCS4ToLower(lct);

    int checkEq,		/* comparison is only for equality */
    int nocase,			/* comparison is not case sensitive */
    int reqlength)		/* requested length; -1 to compare whole
				 * strings */
{
    const char *s1, *s2;
    int empty, length, match, s1len, s2len;
#if TCL_UTF_MAX == 3
    int s1flag = 0, s2flag = 0;
    typedef int (*memCmpFn_t)(const void *, const void *, size_t, int);
#else
    typedef int (*memCmpFn_t)(const void *, const void *, size_t);
#endif
    memCmpFn_t memCmpFn;

    if ((reqlength == 0) || (value1Ptr == value2Ptr)) {
	/*
	 * Always match at 0 chars or if it is the same obj.
	 */
	return 0;
    }

    if (!nocase && TclIsPureByteArray(value1Ptr)
	    && TclIsPureByteArray(value2Ptr)) {
	/*
	 * Use binary versions of comparisons since that won't cause undue
	 * type conversions and it is much faster. Only do this if we're
	 * case-sensitive (which is all that really makes sense with byte
	 * arrays anyway, and we have no memcasecmp() for some reason... :^)
	 */

	s1 = (char *) Tcl_GetByteArrayFromObj(value1Ptr, &s1len);
	s2 = (char *) Tcl_GetByteArrayFromObj(value2Ptr, &s2len);
#if TCL_UTF_MAX == 3
	memCmpFn = MemCmp;
#else
	memCmpFn = memcmp;
#endif
    } else if ((value1Ptr->typePtr == &tclStringType)
	    && (value2Ptr->typePtr == &tclStringType)) {
	/*
	 * Do a unicode-specific comparison if both of the args are of String
	 * type. If the char length == byte length, we can do a memcmp. In
	 * benchmark testing this proved the most efficient check between the
	 * unicode and string comparison operations.
	 */

	if (nocase) {
	    s1 = (char *) Tcl_GetUnicodeFromObj(value1Ptr, &s1len);
	    s2 = (char *) Tcl_GetUnicodeFromObj(value2Ptr, &s2len);
#if TCL_UTF_MAX == 3
	    s1len = NumCodePointsUnicode((Tcl_UniChar *) s1, s1len, &s1flag);
	    s2len = NumCodePointsUnicode((Tcl_UniChar *) s2, s2len, &s2flag);
	    memCmpFn = (memCmpFn_t) UniCharNcasecmp;
#else
	    memCmpFn = (memCmpFn_t)Tcl_UniCharNcasecmp;
#endif
	} else {
	    s1len = Tcl_GetCharLength(value1Ptr);
	    s2len = Tcl_GetCharLength(value2Ptr);
	    if ((s1len == value1Ptr->length)
		    && (value1Ptr->bytes != NULL)
		    && (s2len == value2Ptr->length)
		    && (value2Ptr->bytes != NULL)) {
		s1 = value1Ptr->bytes;
		s2 = value2Ptr->bytes;
#if TCL_UTF_MAX == 3
		memCmpFn = MemCmp;
#else
		memCmpFn = memcmp;
#endif
	    } else {
		s1 = (char *) Tcl_GetUnicode(value1Ptr);
		s2 = (char *) Tcl_GetUnicode(value2Ptr);
		if (
#ifdef WORDS_BIGENDIAN
			1
#else
			checkEq
#endif /* WORDS_BIGENDIAN */
		        ) {
#if TCL_UTF_MAX == 3
		    memCmpFn = MemCmp;
#else
		    memCmpFn = memcmp;
#endif
		    s1len *= sizeof(Tcl_UniChar);
		    s2len *= sizeof(Tcl_UniChar);
		} else {
#if TCL_UTF_MAX == 3
		    s1len = NumCodePointsUnicode((Tcl_UniChar *) s1,
			    s1len, &s1flag);
		    s2len = NumCodePointsUnicode((Tcl_UniChar *) s2,
			    s2len, &s2flag);
		    memCmpFn = (memCmpFn_t) UniCharNcmp;
#else
		    memCmpFn = (memCmpFn_t) Tcl_UniCharNcmp;
#endif
		}
	    }
	}

	if (!nocase && checkEq) {
	    /*
	     * When we have equal-length we can check only for (in)equality.
	     * We can use memcmp() in all (n)eq cases because we don't need to
	     * worry about lexical LE/BE variance.
	     */
#if TCL_UTF_MAX == 3
	    memCmpFn = MemCmp;
#else
	    memCmpFn = memcmp;
#endif
	} else {
	    /*
	     * As a catch-all we will work with UTF-8. We cannot use memcmp()
	     * as that is unsafe with any string containing NUL (\xC0\x80 in
	     * Tcl's utf rep). We can use the more efficient TclpUtfNcmp2 if
	     * we are case-sensitive and no specific length was requested.
	     */
#if TCL_UTF_MAX == 3
	    s1len = NumCodePointsUtf(s1, s1len, &s1flag);
	    s2len = NumCodePointsUtf(s2, s2len, &s2flag);
	    memCmpFn = (memCmpFn_t)
		    (nocase ? UtfNcasecmp : UtfNcmp);
#else
	    if ((reqlength < 0) && !nocase) {
		memCmpFn = (memCmpFn_t) TclpUtfNcmp2;
	    } else {
		s1len = Tcl_NumUtfChars(s1, s1len);

    if (checkEq && (s1len != s2len)) {
	match = 1;		/* This will be reversed below. */
    }  else {
	/*
	 * The comparison function should compare up to the minimum byte
	 * length only.
	 */
#if TCL_UTF_MAX == 3
	match = memCmpFn(s1, s2, (size_t) length, s1flag | (s2flag << 1));
#else
	match = memCmpFn(s1, s2, (size_t) length);
#endif
    }
    if ((match == 0) && (reqlength > length)) {
	match = s1len - s2len;
    }
    return (match > 0) ? 1 : (match < 0) ? -1 : 0;
}


MODULE_SCOPE void	TclSignalExitThread(Tcl_ThreadId id, int result);
MODULE_SCOPE void	TclSpellFix(Tcl_Interp *interp,
			    Tcl_Obj *const *objv, int objc, int subIdx,
			    Tcl_Obj *bad, Tcl_Obj *fix);
MODULE_SCOPE void *	TclStackRealloc(Tcl_Interp *interp, void *ptr,
			    int numBytes);


MODULE_SCOPE int	TclStringCmp (Tcl_Obj *value1Ptr, Tcl_Obj *value2Ptr,
			    int checkEq, int nocase, int reqlength);
MODULE_SCOPE int	TclStringCmpOpts (Tcl_Interp *interp, int objc, Tcl_Obj *const objv[],
			    int *nocase, int *reqlength);
MODULE_SCOPE int	TclStringMatch(const char *str, int strLen,
			    const char *pattern, int ptnLen, int flags);
MODULE_SCOPE int	TclStringMatchObj(Tcl_Obj *stringObj,

    {binary neq} {
	string compare [binary format a100a 0 1] [binary format a100a 0 0]
    } 1 {}
    {binary neq inequal length} {
	string compare [binary format a20a 0 1] [binary format a100a 0 0]
    } 1 {}
    {unicode corner cases} {

	string compare \uD7FF \uD800]


    } -1 {}
    {unicode corner cases} {
	string compare \uD800\uD7FF \uD800\uD800]
    } -1 {}
    {unicode corner cases} {
	string compare \uD800\uD800 \uD800\uD7FF]
    } 1 {}
    {unicode corner cases} {
	string compare \uDBFF \uDC00
    } -1 {}
    {unicode corner cases} {
	string compare \uD83D \uDE00
    } -1 {}
    {unicode corner cases} {