/*
	 * This is a simple one pair string map situation. We make use of a
	 * slightly modified version of the one pair STR_MAP code.
	 */

	int slen, nocase;
	int (*strCmpFn)(const Tcl_UniChar*,const Tcl_UniChar*,unsigned long);
	Tcl_UniChar *p;
#if TCL_UTF_MAX > 3
	Tcl_UniChar wsrclc;
#endif

	numMatches = 0;
	nocase = (cflags & TCL_REG_NOCASE);
	strCmpFn = nocase ? Tcl_UniCharNcasecmp : Tcl_UniCharNcmp;

	wsrc = Tcl_GetUnicodeFromObj(objv[0], &slen);
	wstring = Tcl_GetUnicodeFromObj(objv[1], &wlen);

		    Tcl_AppendUnicodeToObj(resultPtr, wsubspec, wsublen);
		    Tcl_AppendUnicodeToObj(resultPtr, wstring, 1);
		    numMatches++;
		}
		wlen = 0;
	    }
	} else {
#if TCL_UTF_MAX > 3
	    wsrclc = Tcl_UniCharToLower(*wsrc);
#endif
	    for (p = wfirstChar = wstring; wstring < wend; wstring++) {
		if (
#if TCL_UTF_MAX > 3
		    (*wstring == *wsrc ||
			(nocase && Tcl_UniCharToLower(*wstring)==wsrclc)) &&
			(slen==1 || (strCmpFn(wstring, wsrc,
				(unsigned long) slen) == 0))
#else
			!strCmpFn(wstring, wsrc, (unsigned long) slen)
#endif
		) {
		    if (numMatches == 0) {
			resultPtr = Tcl_NewUnicodeObj(wstring, 0);
			Tcl_IncrRefCount(resultPtr);
		    }
		    if (p != wstring) {
			Tcl_AppendUnicodeToObj(resultPtr, p, wstring - p);
			p = wstring + slen;

	 * Special case for one map pair which avoids the extra for loop and
	 * extra calls to get Unicode data. The algorithm is otherwise
	 * identical to the multi-pair case. This will be >30% faster on
	 * larger strings.
	 */

	int mapLen;
	Tcl_UniChar *mapString;
#if TCL_UTF_MAX > 3
	Tcl_UniChar u2lc;
#endif

	ustring2 = Tcl_GetUnicodeFromObj(mapElemv[0], &length2);
	p = ustring1;
	if ((length2 > length1) || (length2 == 0)) {
	    /*
	     * Match string is either longer than input or empty.
	     */

	    ustring1 = end;
	} else {
	    mapString = Tcl_GetUnicodeFromObj(mapElemv[1], &mapLen);
#if TCL_UTF_MAX > 3
	    u2lc = (nocase ? Tcl_UniCharToLower(*ustring2) : 0);
#endif
	    for (; ustring1 < end; ustring1++) {
		if (
#if TCL_UTF_MAX > 3
		    ((*ustring1 == *ustring2) ||
			(nocase&&Tcl_UniCharToLower(*ustring1)==u2lc)) &&
			(length2==1 || strCmpFn(ustring1, ustring2,
				(unsigned long) length2) == 0)
#else
		    !strCmpFn(ustring1, ustring2, (unsigned long) length2)
#endif
		) {
		    if (p != ustring1) {
			Tcl_AppendUnicodeToObj(resultPtr, p, ustring1-p);
			p = ustring1 + length2;
		    } else {
			p += length2;
		    }
		    ustring1 = p - 1;

		    Tcl_AppendUnicodeToObj(resultPtr, mapString, mapLen);
		}
	    }
	}
    } else {
	Tcl_UniChar **mapStrings;
#if TCL_UTF_MAX > 3
	Tcl_UniChar *u2lc = NULL;
#endif
	int *mapLens;

	/*
	 * Precompute pointers to the unicode string and length. This saves us
	 * repeated function calls later, significantly speeding up the
	 * algorithm. We only need the lowercase first char in the nocase
	 * case.
	 */

	mapStrings = TclStackAlloc(interp, mapElemc*2*sizeof(Tcl_UniChar *));
	mapLens = TclStackAlloc(interp, mapElemc * 2 * sizeof(int));
#if TCL_UTF_MAX > 3
	if (nocase) {
	    u2lc = TclStackAlloc(interp, mapElemc * sizeof(Tcl_UniChar));
	}
#endif
	for (index = 0; index < mapElemc; index++) {
	    mapStrings[index] = Tcl_GetUnicodeFromObj(mapElemv[index],
		    mapLens+index);
#if TCL_UTF_MAX > 3
	    if (nocase && ((index % 2) == 0)) {
		u2lc[index/2] = Tcl_UniCharToLower(*mapStrings[index]);
	    }
#endif
	}
	for (p = ustring1; ustring1 < end; ustring1++) {
	    for (index = 0; index < mapElemc; index += 2) {
		/*
		 * Get the key string to match on.
		 */

		ustring2 = mapStrings[index];
		length2 = mapLens[index];
		if (
#if TCL_UTF_MAX > 3
		    (length2 > 0) && ((*ustring1 == *ustring2) || (nocase &&
			(Tcl_UniCharToLower(*ustring1) == u2lc[index/2]))) &&
			/* Restrict max compare length. */
			(end-ustring1 >= length2) && ((length2 == 1) ||
			!strCmpFn(ustring2, ustring1, (unsigned) length2))
#else
		    (length2 > 0) && (end-ustring1 >= length2) &&
			!strCmpFn(ustring2, ustring1, (unsigned) length2)
#endif
		) {
		    if (p != ustring1) {
			/*
			 * Put the skipped chars onto the result first.
			 */

			Tcl_AppendUnicodeToObj(resultPtr, p, ustring1-p);
			p = ustring1 + length2;

		    Tcl_AppendUnicodeToObj(resultPtr,
			    mapStrings[index+1], mapLens[index+1]);
		    break;
		}
	    }
	}
#if TCL_UTF_MAX > 3
	if (nocase) {
	    TclStackFree(interp, u2lc);
	}
#endif
	TclStackFree(interp, mapLens);
	TclStackFree(interp, mapStrings);
    }
    if (p != ustring1) {
	/*
	 * Put the rest of the unmapped chars onto result.
	 */