case 'u':
	count += ParseHex(p+1, (numBytes > 5) ? 4 : numBytes-2, &result);
	if (count == 2) {
	    /*
	     * No hexdigits -> This is just "u".
	     */
	    result = 'u';
#if TCL_UTF_MAX > 3
	} else if ((result & 0xF800) == 0xD800) {
	    result = 0xFFFD;
#else
	} else if ((result & 0xFC00) == 0xDC00) {
	    result = 0xFFFD;
	} else if ((result & 0xFC00) == 0xD800) {
	    if ((count == 6)
		    && (p[5] == '\\') && (p[6] == 'u') && (numBytes >= 10)) {
		/* If high surrogate is immediately followed by a low surrogate
		 * escape, combine them into one character. */
		int low;
		int count2 = ParseHex(p+7, 4, &low);
		if ((count2 == 4) && ((low & 0xFC00) == 0xDC00)) {
		    result = ((result & 0x3FF)<<10 | (low & 0x3FF)) + 0x10000;
		    count += count2 + 2;
		    break;
		}
	    }
	    result = 0xFFFD;
#endif
	}
	break;
    case 'U':
	count += ParseHex(p+1, (numBytes > 9) ? 8 : numBytes-2, &result);
	if (count == 2) {
	    /*
	     * No hexdigits -> This is just "U".

	    /*
	     * Three-byte-character lead byte followed by two trail bytes.
	     */

	    *chPtr = (((byte & 0x0F) << 12)
		    | ((src[1] & 0x3F) << 6) | (src[2] & 0x3F));
	    if (*chPtr > 0x7FF) {
		if ((*chPtr & 0xF800) == 0xD800) {
		    *chPtr = 0xFFFD;
		}
		return 3;
	    }
	}

	/*
	 * A three-byte-character lead-byte not followed by two trail-bytes
	 * represents itself.

	    /*
	     * Three-byte-character lead byte followed by two trail bytes.
	     */

	    *chPtr = (((byte & 0x0F) << 12)
		    | ((src[1] & 0x3F) << 6) | (src[2] & 0x3F));
	    if (*chPtr > 0x7FF) {
		if ((*chPtr & 0xF800) == 0xD800) {
		    *chPtr = 0xFFFD;
		}
		return 3;
	    }
	}

	/*
	 * A three-byte-character lead-byte not followed by two trail-bytes
	 * represents itself.

# Some tests require the testencoding command
testConstraint testencoding [llength [info commands testencoding]]
testConstraint testbytestring [llength [info commands testbytestring]]
testConstraint teststringbytes [llength [info commands teststringbytes]]
testConstraint exec [llength [info commands exec]]
testConstraint testgetencpath [llength [info commands testgetencpath]]
testConstraint tip389 [expr {[string length [format %c 0x10000]] eq 2}]

# TclInitEncodingSubsystem is tested by the rest of this file
# TclFinalizeEncodingSubsystem is not currently tested

test encoding-1.1 {Tcl_GetEncoding: system encoding} -setup {
    set old [encoding system]
} -constraints {testencoding} -body {
    testencoding create foo [namespace origin toutf] [namespace origin fromutf]

    binary scan [teststringbytes $y] H* z
    set z
} c080
test encoding-15.4 {UtfToUtfProc emoji character input} -body {
    set x \xED\xA0\xBD\xED\xB8\x82
    set y [encoding convertfrom utf-8 \xED\xA0\xBD\xED\xB8\x82]
    list [string length $x] $y
} -result "6 \uFFFD\uFFFD"
test encoding-15.5 {UtfToUtfProc emoji character input} {
    set x \xF0\x9F\x98\x82
    set y [encoding convertfrom utf-8 \xF0\x9F\x98\x82]
    list [string length $x] $y
} "4 \U1F602"
test encoding-15.6 {UtfToUtfProc emoji character output} tip389 {
    set x \uDE02\uD83D\uDE02\uD83D
    set y [encoding convertto utf-8 \uDE02\uD83D\uDE02\uD83D]
    binary scan $y H* z
    list [string length $y] $z
} {10 efbfbdf09f9882efbfbd}
test encoding-15.7 {UtfToUtfProc emoji character output} {
    set x \uDE02\uD83D\uD83D
    set y [encoding convertto utf-8 \uDE02\uD83D\uD83D]
    binary scan $y H* z
    list [string length $x] [string length $y] $z
} {3 9 efbfbdefbfbdefbfbd}
test encoding-15.8 {UtfToUtfProc emoji character output} {
    set x \uDE02\uD83D\xE9
    set y [encoding convertto utf-8 \uDE02\uD83D\xE9]
    binary scan $y H* z
    list [string length $x] [string length $y] $z
} {3 8 efbfbdefbfbdc3a9}
test encoding-15.9 {UtfToUtfProc emoji character output} {
    set x \uDE02\uD83DX
    set y [encoding convertto utf-8 \uDE02\uD83DX]
    binary scan $y H* z
    list [string length $x] [string length $y] $z
} {3 7 efbfbdefbfbd58}
test encoding-15.10 {UtfToUtfProc high surrogate character output} {
    set x \uDE02\xE9
    set y [encoding convertto utf-8 \uDE02\xE9]
    binary scan $y H* z
    list [string length $x] [string length $y] $z
} {2 5 efbfbdc3a9}
test encoding-15.11 {UtfToUtfProc low surrogate character output} {
    set x \uDA02\xE9
    set y [encoding convertto utf-8 \uDA02\xE9]
    binary scan $y H* z
    list [string length $x] [string length $y] $z
} {2 5 efbfbdc3a9}
test encoding-15.12 {UtfToUtfProc high surrogate character output} {
    set x \uDE02Y
    set y [encoding convertto utf-8 \uDE02Y]
    binary scan $y H* z
    list [string length $x] [string length $y] $z
} {2 4 efbfbd59}
test encoding-15.13 {UtfToUtfProc low surrogate character output} {
    set x \uDA02Y
    set y [encoding convertto utf-8 \uDA02Y]
    binary scan $y H* z
    list [string length $x] [string length $y] $z
} {2 4 efbfbd59}
test encoding-15.14 {UtfToUtfProc high surrogate character output} {
    set x \uDE02
    set y [encoding convertto utf-8 \uDE02]
    binary scan $y H* z
    list [string length $x] [string length $y] $z
} {1 3 efbfbd}
test encoding-15.15 {UtfToUtfProc low surrogate character output} {
    set x \uDA02
    set y [encoding convertto utf-8 \uDA02]
    binary scan $y H* z
    list [string length $x] [string length $y] $z
} {1 3 efbfbd}
test encoding-15.16 {UtfToUtfProc emoji character output} {
    set x \U1F602
    set y [encoding convertto utf-8 \U1F602]
    binary scan $y H* z
    list [string length $y] $z
} {4 f09f9882}

test encoding-16.1 {Utf16ToUtfProc} -body {
    set val [encoding convertfrom utf-16 NN]
    list $val [format %x [scan $val %c]]
} -result "\u4E4E 4e4e"
test encoding-16.2 {Utf16ToUtfProc} -body {
    set val [encoding convertfrom utf-16 "\xD8\xD8\xDC\xDC"]
    list $val [format %x [scan $val %c]]
} -result "\U460DC 460dc"
test encoding-16.3 {Utf16ToUtfProc} -body {
    set val [encoding convertfrom utf-16 "\xD4\xD4"]
    list $val [format %x [scan $val %c]]
} -result "\uD4D4 d4d4"
test encoding-16.4 {Ucs2ToUtfProc} -body {
    set val [encoding convertfrom ucs-2 NN]
    list $val [format %x [scan $val %c]]
} -result "\u4E4E 4e4e"
test encoding-16.4 {Ucs2ToUtfProc} -body {
    set val [encoding convertfrom ucs-2 "\xD8\xD8\xDC\xDC"]
    list $val [format %x [scan $val %c]]
} -result "\U460DC 460dc"

test encoding-17.1 {UtfToUtf16Proc} -body {
    encoding convertto utf-16 "\U460DC"
} -result "\xD8\xD8\xDC\xDC"
test encoding-17.2 {UtfToUtf16Proc} -body {
    encoding convertto utf-16 "\uD4D4"
} -result "\xD4\xD4"
test encoding-17.3 {UtfToUtf16Proc} -body {
    encoding convertto utf-16 "\uD0D0"
} -result "\xD0\xD0"
test encoding-17.4 {UtfToUcs2Proc} -body {
    encoding convertfrom utf-16 [encoding convertto ucs-2 "\U460DC"]
} -result "\uFFFD"

test encoding-18.1 {TableToUtfProc} {
} {}

test utf-1.7.0 {Tcl_UniCharToUtf: 4 byte sequences} {fullutf Uesc testbytestring} {
    expr {"\U014E4E" eq [testbytestring "\xF0\x94\xB9\x8E"]}
} 1
test utf-1.7.1 {Tcl_UniCharToUtf: 4 byte sequences} {ucs2 Uesc testbytestring} {
    expr {"\U014E4E" eq [testbytestring "\xF0\x94\xB9\x8E"]}
} 0
test utf-1.8 {Tcl_UniCharToUtf: 3 byte sequence, high surrogate} testbytestring {
    expr {"\uD842" eq [testbytestring "\xEF\xBF\xBD"]}
} 1
test utf-1.9 {Tcl_UniCharToUtf: 3 byte sequence, low surrogate} testbytestring {
    expr {"\uDC42" eq [testbytestring "\xEF\xBF\xBD"]}
} 1
test utf-1.10 {Tcl_UniCharToUtf: 3 byte sequence, high surrogate} testbytestring {
    expr {[format %c 0xD842] eq [testbytestring "\xED\xA1\x82"]}
} 1
test utf-1.11 {Tcl_UniCharToUtf: 3 byte sequence, low surrogate} testbytestring {
    expr {[format %c 0xDC42] eq [testbytestring "\xED\xB1\x82"]}
} 1