Add m-esr52 at 52.6.0

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diff --git a/intl/icu/source/common/utrie2.h b/intl/icu/source/common/utrie2.h
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+// Copyright (C) 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+******************************************************************************
+*
+*   Copyright (C) 2001-2014, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+*
+******************************************************************************
+*   file name:  utrie2.h
+*   encoding:   US-ASCII
+*   tab size:   8 (not used)
+*   indentation:4
+*
+*   created on: 2008aug16 (starting from a copy of utrie.h)
+*   created by: Markus W. Scherer
+*/
+
+#ifndef __UTRIE2_H__
+#define __UTRIE2_H__
+
+#include "unicode/utypes.h"
+#include "putilimp.h"
+#include "udataswp.h"
+
+U_CDECL_BEGIN
+
+struct UTrie;  /* forward declaration */
+#ifndef __UTRIE_H__
+typedef struct UTrie UTrie;
+#endif
+
+/**
+ * \file
+ *
+ * This is a common implementation of a Unicode trie.
+ * It is a kind of compressed, serializable table of 16- or 32-bit values associated with
+ * Unicode code points (0..0x10ffff). (A map from code points to integers.)
+ *
+ * This is the second common version of a Unicode trie (hence the name UTrie2).
+ * Compared with UTrie version 1:
+ * - Still splitting BMP code points 11:5 bits for index and data table lookups.
+ * - Still separate data for lead surrogate code _units_ vs. code _points_,
+ *   but the lead surrogate code unit values are not required any more
+ *   for data lookup for supplementary code points.
+ * - The "folding" mechanism is removed. In UTrie version 1, this somewhat
+ *   hard-to-explain mechanism was meant to be used for optimized UTF-16
+ *   processing, with application-specific encoding of indexing bits
+ *   in the lead surrogate data for the associated supplementary code points.
+ * - For the last single-value code point range (ending with U+10ffff),
+ *   the starting code point ("highStart") and the value are stored.
+ * - For supplementary code points U+10000..highStart-1 a three-table lookup
+ *   (two index tables and one data table) is used. The first index
+ *   is truncated, omitting both the BMP portion and the high range.
+ * - There is a special small index for 2-byte UTF-8, and the initial data
+ *   entries are designed for fast 1/2-byte UTF-8 lookup.
+ */
+
+/**
+ * Trie structure.
+ * Use only with public API macros and functions.
+ */
+struct UTrie2;
+typedef struct UTrie2 UTrie2;
+
+/* Public UTrie2 API functions: read-only access ---------------------------- */
+
+/**
+ * Selectors for the width of a UTrie2 data value.
+ */
+enum UTrie2ValueBits {
+    /** 16 bits per UTrie2 data value. */
+    UTRIE2_16_VALUE_BITS,
+    /** 32 bits per UTrie2 data value. */
+    UTRIE2_32_VALUE_BITS,
+    /** Number of selectors for the width of UTrie2 data values. */
+    UTRIE2_COUNT_VALUE_BITS
+};
+typedef enum UTrie2ValueBits UTrie2ValueBits;
+
+/**
+ * Open a frozen trie from its serialized from, stored in 32-bit-aligned memory.
+ * Inverse of utrie2_serialize().
+ * The memory must remain valid and unchanged as long as the trie is used.
+ * You must utrie2_close() the trie once you are done using it.
+ *
+ * @param valueBits selects the data entry size; results in an
+ *                  U_INVALID_FORMAT_ERROR if it does not match the serialized form
+ * @param data a pointer to 32-bit-aligned memory containing the serialized form of a UTrie2
+ * @param length the number of bytes available at data;
+ *               can be more than necessary
+ * @param pActualLength receives the actual number of bytes at data taken up by the trie data;
+ *                      can be NULL
+ * @param pErrorCode an in/out ICU UErrorCode
+ * @return the unserialized trie
+ *
+ * @see utrie2_open
+ * @see utrie2_serialize
+ */
+U_CAPI UTrie2 * U_EXPORT2
+utrie2_openFromSerialized(UTrie2ValueBits valueBits,
+                          const void *data, int32_t length, int32_t *pActualLength,
+                          UErrorCode *pErrorCode);
+
+/**
+ * Open a frozen, empty "dummy" trie.
+ * A dummy trie is an empty trie, used when a real data trie cannot
+ * be loaded. Equivalent to calling utrie2_open() and utrie2_freeze(),
+ * but without internally creating and compacting/serializing the
+ * builder data structure.
+ *
+ * The trie always returns the initialValue,
+ * or the errorValue for out-of-range code points and illegal UTF-8.
+ *
+ * You must utrie2_close() the trie once you are done using it.
+ *
+ * @param valueBits selects the data entry size
+ * @param initialValue the initial value that is set for all code points
+ * @param errorValue the value for out-of-range code points and illegal UTF-8
+ * @param pErrorCode an in/out ICU UErrorCode
+ * @return the dummy trie
+ *
+ * @see utrie2_openFromSerialized
+ * @see utrie2_open
+ */
+U_CAPI UTrie2 * U_EXPORT2
+utrie2_openDummy(UTrie2ValueBits valueBits,
+                 uint32_t initialValue, uint32_t errorValue,
+                 UErrorCode *pErrorCode);
+
+/**
+ * Get a value from a code point as stored in the trie.
+ * Easier to use than UTRIE2_GET16() and UTRIE2_GET32() but slower.
+ * Easier to use because, unlike the macros, this function works on all UTrie2
+ * objects, frozen or not, holding 16-bit or 32-bit data values.
+ *
+ * @param trie the trie
+ * @param c the code point
+ * @return the value
+ */
+U_CAPI uint32_t U_EXPORT2
+utrie2_get32(const UTrie2 *trie, UChar32 c);
+
+/* enumeration callback types */
+
+/**
+ * Callback from utrie2_enum(), extracts a uint32_t value from a
+ * trie value. This value will be passed on to the UTrie2EnumRange function.
+ *
+ * @param context an opaque pointer, as passed into utrie2_enum()
+ * @param value a value from the trie
+ * @return the value that is to be passed on to the UTrie2EnumRange function
+ */
+typedef uint32_t U_CALLCONV
+UTrie2EnumValue(const void *context, uint32_t value);
+
+/**
+ * Callback from utrie2_enum(), is called for each contiguous range
+ * of code points with the same value as retrieved from the trie and
+ * transformed by the UTrie2EnumValue function.
+ *
+ * The callback function can stop the enumeration by returning FALSE.
+ *
+ * @param context an opaque pointer, as passed into utrie2_enum()
+ * @param start the first code point in a contiguous range with value
+ * @param end the last code point in a contiguous range with value (inclusive)
+ * @param value the value that is set for all code points in [start..end]
+ * @return FALSE to stop the enumeration
+ */
+typedef UBool U_CALLCONV
+UTrie2EnumRange(const void *context, UChar32 start, UChar32 end, uint32_t value);
+
+/**
+ * Enumerate efficiently all values in a trie.
+ * Do not modify the trie during the enumeration.
+ *
+ * For each entry in the trie, the value to be delivered is passed through
+ * the UTrie2EnumValue function.
+ * The value is unchanged if that function pointer is NULL.
+ *
+ * For each contiguous range of code points with a given (transformed) value,
+ * the UTrie2EnumRange function is called.
+ *
+ * @param trie a pointer to the trie
+ * @param enumValue a pointer to a function that may transform the trie entry value,
+ *                  or NULL if the values from the trie are to be used directly
+ * @param enumRange a pointer to a function that is called for each contiguous range
+ *                  of code points with the same (transformed) value
+ * @param context an opaque pointer that is passed on to the callback functions
+ */
+U_CAPI void U_EXPORT2
+utrie2_enum(const UTrie2 *trie,
+            UTrie2EnumValue *enumValue, UTrie2EnumRange *enumRange, const void *context);
+
+/* Building a trie ---------------------------------------------------------- */
+
+/**
+ * Open an empty, writable trie. At build time, 32-bit data values are used.
+ * utrie2_freeze() takes a valueBits parameter
+ * which determines the data value width in the serialized and frozen forms.
+ * You must utrie2_close() the trie once you are done using it.
+ *
+ * @param initialValue the initial value that is set for all code points
+ * @param errorValue the value for out-of-range code points and illegal UTF-8
+ * @param pErrorCode an in/out ICU UErrorCode
+ * @return a pointer to the allocated and initialized new trie
+ */
+U_CAPI UTrie2 * U_EXPORT2
+utrie2_open(uint32_t initialValue, uint32_t errorValue, UErrorCode *pErrorCode);
+
+/**
+ * Clone a trie.
+ * You must utrie2_close() the clone once you are done using it.
+ *
+ * @param other the trie to clone
+ * @param pErrorCode an in/out ICU UErrorCode
+ * @return a pointer to the new trie clone
+ */
+U_CAPI UTrie2 * U_EXPORT2
+utrie2_clone(const UTrie2 *other, UErrorCode *pErrorCode);
+
+/**
+ * Clone a trie. The clone will be mutable/writable even if the other trie
+ * is frozen. (See utrie2_freeze().)
+ * You must utrie2_close() the clone once you are done using it.
+ *
+ * @param other the trie to clone
+ * @param pErrorCode an in/out ICU UErrorCode
+ * @return a pointer to the new trie clone
+ */
+U_CAPI UTrie2 * U_EXPORT2
+utrie2_cloneAsThawed(const UTrie2 *other, UErrorCode *pErrorCode);
+
+/**
+ * Close a trie and release associated memory.
+ *
+ * @param trie the trie
+ */
+U_CAPI void U_EXPORT2
+utrie2_close(UTrie2 *trie);
+
+/**
+ * Set a value for a code point.
+ *
+ * @param trie the unfrozen trie
+ * @param c the code point
+ * @param value the value
+ * @param pErrorCode an in/out ICU UErrorCode; among other possible error codes:
+ * - U_NO_WRITE_PERMISSION if the trie is frozen
+ */
+U_CAPI void U_EXPORT2
+utrie2_set32(UTrie2 *trie, UChar32 c, uint32_t value, UErrorCode *pErrorCode);
+
+/**
+ * Set a value in a range of code points [start..end].
+ * All code points c with start<=c<=end will get the value if
+ * overwrite is TRUE or if the old value is the initial value.
+ *
+ * @param trie the unfrozen trie
+ * @param start the first code point to get the value
+ * @param end the last code point to get the value (inclusive)
+ * @param value the value
+ * @param overwrite flag for whether old non-initial values are to be overwritten
+ * @param pErrorCode an in/out ICU UErrorCode; among other possible error codes:
+ * - U_NO_WRITE_PERMISSION if the trie is frozen
+ */
+U_CAPI void U_EXPORT2
+utrie2_setRange32(UTrie2 *trie,
+                  UChar32 start, UChar32 end,
+                  uint32_t value, UBool overwrite,
+                  UErrorCode *pErrorCode);
+
+/**
+ * Freeze a trie. Make it immutable (read-only) and compact it,
+ * ready for serialization and for use with fast macros.
+ * Functions to set values will fail after serializing.
+ *
+ * A trie can be frozen only once. If this function is called again with different
+ * valueBits then it will set a U_ILLEGAL_ARGUMENT_ERROR.
+ *
+ * @param trie the trie
+ * @param valueBits selects the data entry size; if smaller than 32 bits, then
+ *                  the values stored in the trie will be truncated
+ * @param pErrorCode an in/out ICU UErrorCode; among other possible error codes:
+ * - U_INDEX_OUTOFBOUNDS_ERROR if the compacted index or data arrays are too long
+ *                             for serialization
+ *                             (the trie will be immutable and usable,
+ *                             but not frozen and not usable with the fast macros)
+ *
+ * @see utrie2_cloneAsThawed
+ */
+U_CAPI void U_EXPORT2
+utrie2_freeze(UTrie2 *trie, UTrie2ValueBits valueBits, UErrorCode *pErrorCode);
+
+/**
+ * Test if the trie is frozen. (See utrie2_freeze().)
+ *
+ * @param trie the trie
+ * @return TRUE if the trie is frozen, that is, immutable, ready for serialization
+ *         and for use with fast macros
+ */
+U_CAPI UBool U_EXPORT2
+utrie2_isFrozen(const UTrie2 *trie);
+
+/**
+ * Serialize a frozen trie into 32-bit aligned memory.
+ * If the trie is not frozen, then the function returns with a U_ILLEGAL_ARGUMENT_ERROR.
+ * A trie can be serialized multiple times.
+ *
+ * @param trie the frozen trie
+ * @param data a pointer to 32-bit-aligned memory to be filled with the trie data,
+ *             can be NULL if capacity==0
+ * @param capacity the number of bytes available at data,
+ *                 or 0 for preflighting
+ * @param pErrorCode an in/out ICU UErrorCode; among other possible error codes:
+ * - U_BUFFER_OVERFLOW_ERROR if the data storage block is too small for serialization
+ * - U_ILLEGAL_ARGUMENT_ERROR if the trie is not frozen or the data and capacity
+ *                            parameters are bad
+ * @return the number of bytes written or needed for the trie
+ *
+ * @see utrie2_openFromSerialized()
+ */
+U_CAPI int32_t U_EXPORT2
+utrie2_serialize(const UTrie2 *trie,
+                 void *data, int32_t capacity,
+                 UErrorCode *pErrorCode);
+
+/* Public UTrie2 API: miscellaneous functions ------------------------------- */
+
+/**
+ * Get the UTrie version from 32-bit-aligned memory containing the serialized form
+ * of either a UTrie (version 1) or a UTrie2 (version 2).
+ *
+ * @param data a pointer to 32-bit-aligned memory containing the serialized form
+ *             of a UTrie, version 1 or 2
+ * @param length the number of bytes available at data;
+ *               can be more than necessary (see return value)
+ * @param anyEndianOk If FALSE, only platform-endian serialized forms are recognized.
+ *                    If TRUE, opposite-endian serialized forms are recognized as well.
+ * @return the UTrie version of the serialized form, or 0 if it is not
+ *         recognized as a serialized UTrie
+ */
+U_CAPI int32_t U_EXPORT2
+utrie2_getVersion(const void *data, int32_t length, UBool anyEndianOk);
+
+/**
+ * Swap a serialized UTrie2.
+ * @internal
+ */
+U_CAPI int32_t U_EXPORT2
+utrie2_swap(const UDataSwapper *ds,
+            const void *inData, int32_t length, void *outData,
+            UErrorCode *pErrorCode);
+
+/**
+ * Swap a serialized UTrie or UTrie2.
+ * @internal
+ */
+U_CAPI int32_t U_EXPORT2
+utrie2_swapAnyVersion(const UDataSwapper *ds,
+                      const void *inData, int32_t length, void *outData,
+                      UErrorCode *pErrorCode);
+
+/**
+ * Build a UTrie2 (version 2) from a UTrie (version 1).
+ * Enumerates all values in the UTrie and builds a UTrie2 with the same values.
+ * The resulting UTrie2 will be frozen.
+ *
+ * @param trie1 the runtime UTrie structure to be enumerated
+ * @param errorValue the value for out-of-range code points and illegal UTF-8
+ * @param pErrorCode an in/out ICU UErrorCode
+ * @return The frozen UTrie2 with the same values as the UTrie.
+ */
+U_CAPI UTrie2 * U_EXPORT2
+utrie2_fromUTrie(const UTrie *trie1, uint32_t errorValue, UErrorCode *pErrorCode);
+
+/* Public UTrie2 API macros ------------------------------------------------- */
+
+/*
+ * These macros provide fast data lookup from a frozen trie.
+ * They will crash when used on an unfrozen trie.
+ */
+
+/**
+ * Return a 16-bit trie value from a code point, with range checking.
+ * Returns trie->errorValue if c is not in the range 0..U+10ffff.
+ *
+ * @param trie (const UTrie2 *, in) a frozen trie
+ * @param c (UChar32, in) the input code point
+ * @return (uint16_t) The code point's trie value.
+ */
+#define UTRIE2_GET16(trie, c) _UTRIE2_GET((trie), index, (trie)->indexLength, (c))
+
+/**
+ * Return a 32-bit trie value from a code point, with range checking.
+ * Returns trie->errorValue if c is not in the range 0..U+10ffff.
+ *
+ * @param trie (const UTrie2 *, in) a frozen trie
+ * @param c (UChar32, in) the input code point
+ * @return (uint32_t) The code point's trie value.
+ */
+#define UTRIE2_GET32(trie, c) _UTRIE2_GET((trie), data32, 0, (c))
+
+/**
+ * UTF-16: Get the next code point (UChar32 c, out), post-increment src,
+ * and get a 16-bit value from the trie.
+ *
+ * @param trie (const UTrie2 *, in) a frozen trie
+ * @param src (const UChar *, in/out) the source text pointer
+ * @param limit (const UChar *, in) the limit pointer for the text, or NULL if NUL-terminated
+ * @param c (UChar32, out) variable for the code point
+ * @param result (uint16_t, out) uint16_t variable for the trie lookup result
+ */
+#define UTRIE2_U16_NEXT16(trie, src, limit, c, result) _UTRIE2_U16_NEXT(trie, index, src, limit, c, result)
+
+/**
+ * UTF-16: Get the next code point (UChar32 c, out), post-increment src,
+ * and get a 32-bit value from the trie.
+ *
+ * @param trie (const UTrie2 *, in) a frozen trie
+ * @param src (const UChar *, in/out) the source text pointer
+ * @param limit (const UChar *, in) the limit pointer for the text, or NULL if NUL-terminated
+ * @param c (UChar32, out) variable for the code point
+ * @param result (uint32_t, out) uint32_t variable for the trie lookup result
+ */
+#define UTRIE2_U16_NEXT32(trie, src, limit, c, result) _UTRIE2_U16_NEXT(trie, data32, src, limit, c, result)
+
+/**
+ * UTF-16: Get the previous code point (UChar32 c, out), pre-decrement src,
+ * and get a 16-bit value from the trie.
+ *
+ * @param trie (const UTrie2 *, in) a frozen trie
+ * @param start (const UChar *, in) the start pointer for the text
+ * @param src (const UChar *, in/out) the source text pointer
+ * @param c (UChar32, out) variable for the code point
+ * @param result (uint16_t, out) uint16_t variable for the trie lookup result
+ */
+#define UTRIE2_U16_PREV16(trie, start, src, c, result) _UTRIE2_U16_PREV(trie, index, start, src, c, result)
+
+/**
+ * UTF-16: Get the previous code point (UChar32 c, out), pre-decrement src,
+ * and get a 32-bit value from the trie.
+ *
+ * @param trie (const UTrie2 *, in) a frozen trie
+ * @param start (const UChar *, in) the start pointer for the text
+ * @param src (const UChar *, in/out) the source text pointer
+ * @param c (UChar32, out) variable for the code point
+ * @param result (uint32_t, out) uint32_t variable for the trie lookup result
+ */
+#define UTRIE2_U16_PREV32(trie, start, src, c, result) _UTRIE2_U16_PREV(trie, data32, start, src, c, result)
+
+/**
+ * UTF-8: Post-increment src and get a 16-bit value from the trie.
+ *
+ * @param trie (const UTrie2 *, in) a frozen trie
+ * @param src (const char *, in/out) the source text pointer
+ * @param limit (const char *, in) the limit pointer for the text (must not be NULL)
+ * @param result (uint16_t, out) uint16_t variable for the trie lookup result
+ */
+#define UTRIE2_U8_NEXT16(trie, src, limit, result)\
+    _UTRIE2_U8_NEXT(trie, data16, index, src, limit, result)
+
+/**
+ * UTF-8: Post-increment src and get a 32-bit value from the trie.
+ *
+ * @param trie (const UTrie2 *, in) a frozen trie
+ * @param src (const char *, in/out) the source text pointer
+ * @param limit (const char *, in) the limit pointer for the text (must not be NULL)
+ * @param result (uint16_t, out) uint32_t variable for the trie lookup result
+ */
+#define UTRIE2_U8_NEXT32(trie, src, limit, result) \
+    _UTRIE2_U8_NEXT(trie, data32, data32, src, limit, result)
+
+/**
+ * UTF-8: Pre-decrement src and get a 16-bit value from the trie.
+ *
+ * @param trie (const UTrie2 *, in) a frozen trie
+ * @param start (const char *, in) the start pointer for the text
+ * @param src (const char *, in/out) the source text pointer
+ * @param result (uint16_t, out) uint16_t variable for the trie lookup result
+ */
+#define UTRIE2_U8_PREV16(trie, start, src, result) \
+    _UTRIE2_U8_PREV(trie, data16, index, start, src, result)
+
+/**
+ * UTF-8: Pre-decrement src and get a 32-bit value from the trie.
+ *
+ * @param trie (const UTrie2 *, in) a frozen trie
+ * @param start (const char *, in) the start pointer for the text
+ * @param src (const char *, in/out) the source text pointer
+ * @param result (uint16_t, out) uint32_t variable for the trie lookup result
+ */
+#define UTRIE2_U8_PREV32(trie, start, src, result) \
+    _UTRIE2_U8_PREV(trie, data32, data32, start, src, result)
+
+/* Public UTrie2 API: optimized UTF-16 access ------------------------------- */
+
+/*
+ * The following functions and macros are used for highly optimized UTF-16
+ * text processing. The UTRIE2_U16_NEXTxy() macros do not depend on these.
+ *
+ * A UTrie2 stores separate values for lead surrogate code _units_ vs. code _points_.
+ * UTF-16 text processing can be optimized by detecting surrogate pairs and
+ * assembling supplementary code points only when there is non-trivial data
+ * available.
+ *
+ * At build-time, use utrie2_enumForLeadSurrogate() to see if there
+ * is non-trivial (non-initialValue) data for any of the supplementary
+ * code points associated with a lead surrogate.
+ * If so, then set a special (application-specific) value for the
+ * lead surrogate code _unit_, with utrie2_set32ForLeadSurrogateCodeUnit().
+ *
+ * At runtime, use UTRIE2_GET16_FROM_U16_SINGLE_LEAD() or
+ * UTRIE2_GET32_FROM_U16_SINGLE_LEAD() per code unit. If there is non-trivial
+ * data and the code unit is a lead surrogate, then check if a trail surrogate
+ * follows. If so, assemble the supplementary code point with
+ * U16_GET_SUPPLEMENTARY() and look up its value with UTRIE2_GET16_FROM_SUPP()
+ * or UTRIE2_GET32_FROM_SUPP(); otherwise reset the lead
+ * surrogate's value or do a code point lookup for it.
+ *
+ * If there is only trivial data for lead and trail surrogates, then processing
+ * can often skip them. For example, in normalization or case mapping
+ * all characters that do not have any mappings are simply copied as is.
+ */
+
+/**
+ * Get a value from a lead surrogate code unit as stored in the trie.
+ *
+ * @param trie the trie
+ * @param c the code unit (U+D800..U+DBFF)
+ * @return the value
+ */
+U_CAPI uint32_t U_EXPORT2
+utrie2_get32FromLeadSurrogateCodeUnit(const UTrie2 *trie, UChar32 c);
+
+/**
+ * Enumerate the trie values for the 1024=0x400 code points
+ * corresponding to a given lead surrogate.
+ * For example, for the lead surrogate U+D87E it will enumerate the values
+ * for [U+2F800..U+2FC00[.
+ * Used by data builder code that sets special lead surrogate code unit values
+ * for optimized UTF-16 string processing.
+ *
+ * Do not modify the trie during the enumeration.
+ *
+ * Except for the limited code point range, this functions just like utrie2_enum():
+ * For each entry in the trie, the value to be delivered is passed through
+ * the UTrie2EnumValue function.
+ * The value is unchanged if that function pointer is NULL.
+ *
+ * For each contiguous range of code points with a given (transformed) value,
+ * the UTrie2EnumRange function is called.
+ *
+ * @param trie a pointer to the trie
+ * @param enumValue a pointer to a function that may transform the trie entry value,
+ *                  or NULL if the values from the trie are to be used directly
+ * @param enumRange a pointer to a function that is called for each contiguous range
+ *                  of code points with the same (transformed) value
+ * @param context an opaque pointer that is passed on to the callback functions
+ */
+U_CAPI void U_EXPORT2
+utrie2_enumForLeadSurrogate(const UTrie2 *trie, UChar32 lead,
+                            UTrie2EnumValue *enumValue, UTrie2EnumRange *enumRange,
+                            const void *context);
+
+/**
+ * Set a value for a lead surrogate code unit.
+ *
+ * @param trie the unfrozen trie
+ * @param lead the lead surrogate code unit (U+D800..U+DBFF)
+ * @param value the value
+ * @param pErrorCode an in/out ICU UErrorCode; among other possible error codes:
+ * - U_NO_WRITE_PERMISSION if the trie is frozen
+ */
+U_CAPI void U_EXPORT2
+utrie2_set32ForLeadSurrogateCodeUnit(UTrie2 *trie,
+                                     UChar32 lead, uint32_t value,
+                                     UErrorCode *pErrorCode);
+
+/**
+ * Return a 16-bit trie value from a UTF-16 single/lead code unit (<=U+ffff).
+ * Same as UTRIE2_GET16() if c is a BMP code point except for lead surrogates,
+ * but smaller and faster.
+ *
+ * @param trie (const UTrie2 *, in) a frozen trie
+ * @param c (UChar32, in) the input code unit, must be 0<=c<=U+ffff
+ * @return (uint16_t) The code unit's trie value.
+ */
+#define UTRIE2_GET16_FROM_U16_SINGLE_LEAD(trie, c) _UTRIE2_GET_FROM_U16_SINGLE_LEAD((trie), index, c)
+
+/**
+ * Return a 32-bit trie value from a UTF-16 single/lead code unit (<=U+ffff).
+ * Same as UTRIE2_GET32() if c is a BMP code point except for lead surrogates,
+ * but smaller and faster.
+ *
+ * @param trie (const UTrie2 *, in) a frozen trie
+ * @param c (UChar32, in) the input code unit, must be 0<=c<=U+ffff
+ * @return (uint32_t) The code unit's trie value.
+ */
+#define UTRIE2_GET32_FROM_U16_SINGLE_LEAD(trie, c) _UTRIE2_GET_FROM_U16_SINGLE_LEAD((trie), data32, c)
+
+/**
+ * Return a 16-bit trie value from a supplementary code point (U+10000..U+10ffff).
+ *
+ * @param trie (const UTrie2 *, in) a frozen trie
+ * @param c (UChar32, in) the input code point, must be U+10000<=c<=U+10ffff
+ * @return (uint16_t) The code point's trie value.
+ */
+#define UTRIE2_GET16_FROM_SUPP(trie, c) _UTRIE2_GET_FROM_SUPP((trie), index, c)
+
+/**
+ * Return a 32-bit trie value from a supplementary code point (U+10000..U+10ffff).
+ *
+ * @param trie (const UTrie2 *, in) a frozen trie
+ * @param c (UChar32, in) the input code point, must be U+10000<=c<=U+10ffff
+ * @return (uint32_t) The code point's trie value.
+ */
+#define UTRIE2_GET32_FROM_SUPP(trie, c) _UTRIE2_GET_FROM_SUPP((trie), data32, c)
+
+U_CDECL_END
+
+/* C++ convenience wrappers ------------------------------------------------- */
+
+#ifdef __cplusplus
+
+#include "unicode/utf.h"
+#include "mutex.h"
+
+U_NAMESPACE_BEGIN
+
+// Use the Forward/Backward subclasses below.
+class UTrie2StringIterator : public UMemory {
+public:
+    UTrie2StringIterator(const UTrie2 *t, const UChar *p) :
+        trie(t), codePointStart(p), codePointLimit(p), codePoint(U_SENTINEL) {}
+
+    const UTrie2 *trie;
+    const UChar *codePointStart, *codePointLimit;
+    UChar32 codePoint;
+};
+
+class BackwardUTrie2StringIterator : public UTrie2StringIterator {
+public:
+    BackwardUTrie2StringIterator(const UTrie2 *t, const UChar *s, const UChar *p) :
+        UTrie2StringIterator(t, p), start(s) {}
+
+    uint16_t previous16();
+
+    const UChar *start;
+};
+
+class ForwardUTrie2StringIterator : public UTrie2StringIterator {
+public:
+    // Iteration limit l can be NULL.
+    // In that case, the caller must detect c==0 and stop.
+    ForwardUTrie2StringIterator(const UTrie2 *t, const UChar *p, const UChar *l) :
+        UTrie2StringIterator(t, p), limit(l) {}
+
+    uint16_t next16();
+
+    const UChar *limit;
+};
+
+U_NAMESPACE_END
+
+#endif
+
+/* Internal definitions ----------------------------------------------------- */
+
+U_CDECL_BEGIN
+
+/** Build-time trie structure. */
+struct UNewTrie2;
+typedef struct UNewTrie2 UNewTrie2;
+
+/*
+ * Trie structure definition.
+ *
+ * Either the data table is 16 bits wide and accessed via the index
+ * pointer, with each index item increased by indexLength;
+ * in this case, data32==NULL, and data16 is used for direct ASCII access.
+ *
+ * Or the data table is 32 bits wide and accessed via the data32 pointer.
+ */
+struct UTrie2 {
+    /* protected: used by macros and functions for reading values */
+    const uint16_t *index;
+    const uint16_t *data16;     /* for fast UTF-8 ASCII access, if 16b data */
+    const uint32_t *data32;     /* NULL if 16b data is used via index */
+
+    int32_t indexLength, dataLength;
+    uint16_t index2NullOffset;  /* 0xffff if there is no dedicated index-2 null block */
+    uint16_t dataNullOffset;
+    uint32_t initialValue;
+    /** Value returned for out-of-range code points and illegal UTF-8. */
+    uint32_t errorValue;
+
+    /* Start of the last range which ends at U+10ffff, and its value. */
+    UChar32 highStart;
+    int32_t highValueIndex;
+
+    /* private: used by builder and unserialization functions */
+    void *memory;           /* serialized bytes; NULL if not frozen yet */
+    int32_t length;         /* number of serialized bytes at memory; 0 if not frozen yet */
+    UBool isMemoryOwned;    /* TRUE if the trie owns the memory */
+    UBool padding1;
+    int16_t padding2;
+    UNewTrie2 *newTrie;     /* builder object; NULL when frozen */
+};
+
+/**
+ * Trie constants, defining shift widths, index array lengths, etc.
+ *
+ * These are needed for the runtime macros but users can treat these as
+ * implementation details and skip to the actual public API further below.
+ */
+enum {
+    /** Shift size for getting the index-1 table offset. */
+    UTRIE2_SHIFT_1=6+5,
+
+    /** Shift size for getting the index-2 table offset. */
+    UTRIE2_SHIFT_2=5,
+
+    /**
+     * Difference between the two shift sizes,
+     * for getting an index-1 offset from an index-2 offset. 6=11-5
+     */
+    UTRIE2_SHIFT_1_2=UTRIE2_SHIFT_1-UTRIE2_SHIFT_2,
+
+    /**
+     * Number of index-1 entries for the BMP. 32=0x20
+     * This part of the index-1 table is omitted from the serialized form.
+     */
+    UTRIE2_OMITTED_BMP_INDEX_1_LENGTH=0x10000>>UTRIE2_SHIFT_1,
+
+    /** Number of code points per index-1 table entry. 2048=0x800 */
+    UTRIE2_CP_PER_INDEX_1_ENTRY=1<<UTRIE2_SHIFT_1,
+
+    /** Number of entries in an index-2 block. 64=0x40 */
+    UTRIE2_INDEX_2_BLOCK_LENGTH=1<<UTRIE2_SHIFT_1_2,
+
+    /** Mask for getting the lower bits for the in-index-2-block offset. */
+    UTRIE2_INDEX_2_MASK=UTRIE2_INDEX_2_BLOCK_LENGTH-1,
+
+    /** Number of entries in a data block. 32=0x20 */
+    UTRIE2_DATA_BLOCK_LENGTH=1<<UTRIE2_SHIFT_2,
+
+    /** Mask for getting the lower bits for the in-data-block offset. */
+    UTRIE2_DATA_MASK=UTRIE2_DATA_BLOCK_LENGTH-1,
+
+    /**
+     * Shift size for shifting left the index array values.
+     * Increases possible data size with 16-bit index values at the cost
+     * of compactability.
+     * This requires data blocks to be aligned by UTRIE2_DATA_GRANULARITY.
+     */
+    UTRIE2_INDEX_SHIFT=2,
+
+    /** The alignment size of a data block. Also the granularity for compaction. */
+    UTRIE2_DATA_GRANULARITY=1<<UTRIE2_INDEX_SHIFT,
+
+    /* Fixed layout of the first part of the index array. ------------------- */
+
+    /**
+     * The BMP part of the index-2 table is fixed and linear and starts at offset 0.
+     * Length=2048=0x800=0x10000>>UTRIE2_SHIFT_2.
+     */
+    UTRIE2_INDEX_2_OFFSET=0,
+
+    /**
+     * The part of the index-2 table for U+D800..U+DBFF stores values for
+     * lead surrogate code _units_ not code _points_.
+     * Values for lead surrogate code _points_ are indexed with this portion of the table.
+     * Length=32=0x20=0x400>>UTRIE2_SHIFT_2. (There are 1024=0x400 lead surrogates.)
+     */
+    UTRIE2_LSCP_INDEX_2_OFFSET=0x10000>>UTRIE2_SHIFT_2,
+    UTRIE2_LSCP_INDEX_2_LENGTH=0x400>>UTRIE2_SHIFT_2,
+
+    /** Count the lengths of both BMP pieces. 2080=0x820 */
+    UTRIE2_INDEX_2_BMP_LENGTH=UTRIE2_LSCP_INDEX_2_OFFSET+UTRIE2_LSCP_INDEX_2_LENGTH,
+
+    /**
+     * The 2-byte UTF-8 version of the index-2 table follows at offset 2080=0x820.
+     * Length 32=0x20 for lead bytes C0..DF, regardless of UTRIE2_SHIFT_2.
+     */
+    UTRIE2_UTF8_2B_INDEX_2_OFFSET=UTRIE2_INDEX_2_BMP_LENGTH,
+    UTRIE2_UTF8_2B_INDEX_2_LENGTH=0x800>>6,  /* U+0800 is the first code point after 2-byte UTF-8 */
+
+    /**
+     * The index-1 table, only used for supplementary code points, at offset 2112=0x840.
+     * Variable length, for code points up to highStart, where the last single-value range starts.
+     * Maximum length 512=0x200=0x100000>>UTRIE2_SHIFT_1.
+     * (For 0x100000 supplementary code points U+10000..U+10ffff.)
+     *
+     * The part of the index-2 table for supplementary code points starts
+     * after this index-1 table.
+     *
+     * Both the index-1 table and the following part of the index-2 table
+     * are omitted completely if there is only BMP data.
+     */
+    UTRIE2_INDEX_1_OFFSET=UTRIE2_UTF8_2B_INDEX_2_OFFSET+UTRIE2_UTF8_2B_INDEX_2_LENGTH,
+    UTRIE2_MAX_INDEX_1_LENGTH=0x100000>>UTRIE2_SHIFT_1,
+
+    /*
+     * Fixed layout of the first part of the data array. -----------------------
+     * Starts with 4 blocks (128=0x80 entries) for ASCII.
+     */
+
+    /**
+     * The illegal-UTF-8 data block follows the ASCII block, at offset 128=0x80.
+     * Used with linear access for single bytes 0..0xbf for simple error handling.
+     * Length 64=0x40, not UTRIE2_DATA_BLOCK_LENGTH.
+     */
+    UTRIE2_BAD_UTF8_DATA_OFFSET=0x80,
+
+    /** The start of non-linear-ASCII data blocks, at offset 192=0xc0. */
+    UTRIE2_DATA_START_OFFSET=0xc0
+};
+
+/* Internal functions and macros -------------------------------------------- */
+
+/**
+ * Internal function for part of the UTRIE2_U8_NEXTxx() macro implementations.
+ * Do not call directly.
+ * @internal
+ */
+U_INTERNAL int32_t U_EXPORT2
+utrie2_internalU8NextIndex(const UTrie2 *trie, UChar32 c,
+                           const uint8_t *src, const uint8_t *limit);
+
+/**
+ * Internal function for part of the UTRIE2_U8_PREVxx() macro implementations.
+ * Do not call directly.
+ * @internal
+ */
+U_INTERNAL int32_t U_EXPORT2
+utrie2_internalU8PrevIndex(const UTrie2 *trie, UChar32 c,
+                           const uint8_t *start, const uint8_t *src);
+
+
+/** Internal low-level trie getter. Returns a data index. */
+#define _UTRIE2_INDEX_RAW(offset, trieIndex, c) \
+    (((int32_t)((trieIndex)[(offset)+((c)>>UTRIE2_SHIFT_2)]) \
+    <<UTRIE2_INDEX_SHIFT)+ \
+    ((c)&UTRIE2_DATA_MASK))
+
+/** Internal trie getter from a UTF-16 single/lead code unit. Returns the data index. */
+#define _UTRIE2_INDEX_FROM_U16_SINGLE_LEAD(trieIndex, c) _UTRIE2_INDEX_RAW(0, trieIndex, c)
+
+/** Internal trie getter from a lead surrogate code point (D800..DBFF). Returns the data index. */
+#define _UTRIE2_INDEX_FROM_LSCP(trieIndex, c) \
+    _UTRIE2_INDEX_RAW(UTRIE2_LSCP_INDEX_2_OFFSET-(0xd800>>UTRIE2_SHIFT_2), trieIndex, c)
+
+/** Internal trie getter from a BMP code point. Returns the data index. */
+#define _UTRIE2_INDEX_FROM_BMP(trieIndex, c) \
+    _UTRIE2_INDEX_RAW(U_IS_LEAD(c) ? UTRIE2_LSCP_INDEX_2_OFFSET-(0xd800>>UTRIE2_SHIFT_2) : 0, \
+                      trieIndex, c)
+
+/** Internal trie getter from a supplementary code point below highStart. Returns the data index. */
+#define _UTRIE2_INDEX_FROM_SUPP(trieIndex, c) \
+    (((int32_t)((trieIndex)[ \
+        (trieIndex)[(UTRIE2_INDEX_1_OFFSET-UTRIE2_OMITTED_BMP_INDEX_1_LENGTH)+ \
+                      ((c)>>UTRIE2_SHIFT_1)]+ \
+        (((c)>>UTRIE2_SHIFT_2)&UTRIE2_INDEX_2_MASK)]) \
+    <<UTRIE2_INDEX_SHIFT)+ \
+    ((c)&UTRIE2_DATA_MASK))
+
+/**
+ * Internal trie getter from a code point, with checking that c is in 0..10FFFF.
+ * Returns the data index.
+ */
+#define _UTRIE2_INDEX_FROM_CP(trie, asciiOffset, c) \
+    ((uint32_t)(c)<0xd800 ? \
+        _UTRIE2_INDEX_RAW(0, (trie)->index, c) : \
+        (uint32_t)(c)<=0xffff ? \
+            _UTRIE2_INDEX_RAW( \
+                (c)<=0xdbff ? UTRIE2_LSCP_INDEX_2_OFFSET-(0xd800>>UTRIE2_SHIFT_2) : 0, \
+                (trie)->index, c) : \
+            (uint32_t)(c)>0x10ffff ? \
+                (asciiOffset)+UTRIE2_BAD_UTF8_DATA_OFFSET : \
+                (c)>=(trie)->highStart ? \
+                    (trie)->highValueIndex : \
+                    _UTRIE2_INDEX_FROM_SUPP((trie)->index, c))
+
+/** Internal trie getter from a UTF-16 single/lead code unit. Returns the data. */
+#define _UTRIE2_GET_FROM_U16_SINGLE_LEAD(trie, data, c) \
+    (trie)->data[_UTRIE2_INDEX_FROM_U16_SINGLE_LEAD((trie)->index, c)]
+
+/** Internal trie getter from a supplementary code point. Returns the data. */
+#define _UTRIE2_GET_FROM_SUPP(trie, data, c) \
+    (trie)->data[(c)>=(trie)->highStart ? (trie)->highValueIndex : \
+                 _UTRIE2_INDEX_FROM_SUPP((trie)->index, c)]
+
+/**
+ * Internal trie getter from a code point, with checking that c is in 0..10FFFF.
+ * Returns the data.
+ */
+#define _UTRIE2_GET(trie, data, asciiOffset, c) \
+    (trie)->data[_UTRIE2_INDEX_FROM_CP(trie, asciiOffset, c)]
+
+/** Internal next-post-increment: get the next code point (c) and its data. */
+#define _UTRIE2_U16_NEXT(trie, data, src, limit, c, result) { \
+    { \
+        uint16_t __c2; \
+        (c)=*(src)++; \
+        if(!U16_IS_LEAD(c)) { \
+            (result)=_UTRIE2_GET_FROM_U16_SINGLE_LEAD(trie, data, c); \
+        } else if((src)==(limit) || !U16_IS_TRAIL(__c2=*(src))) { \
+            (result)=(trie)->data[_UTRIE2_INDEX_FROM_LSCP((trie)->index, c)]; \
+        } else { \
+            ++(src); \
+            (c)=U16_GET_SUPPLEMENTARY((c), __c2); \
+            (result)=_UTRIE2_GET_FROM_SUPP((trie), data, (c)); \
+        } \
+    } \
+}
+
+/** Internal pre-decrement-previous: get the previous code point (c) and its data */
+#define _UTRIE2_U16_PREV(trie, data, start, src, c, result) { \
+    { \
+        uint16_t __c2; \
+        (c)=*--(src); \
+        if(!U16_IS_TRAIL(c) || (src)==(start) || !U16_IS_LEAD(__c2=*((src)-1))) { \
+            (result)=(trie)->data[_UTRIE2_INDEX_FROM_BMP((trie)->index, c)]; \
+        } else { \
+            --(src); \
+            (c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \
+            (result)=_UTRIE2_GET_FROM_SUPP((trie), data, (c)); \
+        } \
+    } \
+}
+
+/** Internal UTF-8 next-post-increment: get the next code point's data. */
+#define _UTRIE2_U8_NEXT(trie, ascii, data, src, limit, result) { \
+    uint8_t __lead=(uint8_t)*(src)++; \
+    if(__lead<0xc0) { \
+        (result)=(trie)->ascii[__lead]; \
+    } else { \
+        uint8_t __t1, __t2; \
+        if( /* handle U+0000..U+07FF inline */ \
+            __lead<0xe0 && (src)<(limit) && \
+            (__t1=(uint8_t)(*(src)-0x80))<=0x3f \
+        ) { \
+            ++(src); \
+            (result)=(trie)->data[ \
+                (trie)->index[(UTRIE2_UTF8_2B_INDEX_2_OFFSET-0xc0)+__lead]+ \
+                __t1]; \
+        } else if( /* handle U+0000..U+CFFF inline */ \
+            __lead<0xed && ((src)+1)<(limit) && \
+            (__t1=(uint8_t)(*(src)-0x80))<=0x3f && (__lead>0xe0 || __t1>=0x20) && \
+            (__t2=(uint8_t)(*((src)+1)-0x80))<= 0x3f \
+        ) { \
+            (src)+=2; \
+            (result)=(trie)->data[ \
+                ((int32_t)((trie)->index[((__lead-0xe0)<<(12-UTRIE2_SHIFT_2))+ \
+                                         (__t1<<(6-UTRIE2_SHIFT_2))+(__t2>>UTRIE2_SHIFT_2)]) \
+                <<UTRIE2_INDEX_SHIFT)+ \
+                (__t2&UTRIE2_DATA_MASK)]; \
+        } else { \
+            int32_t __index=utrie2_internalU8NextIndex((trie), __lead, (const uint8_t *)(src), \
+                                                                       (const uint8_t *)(limit)); \
+            (src)+=__index&7; \
+            (result)=(trie)->data[__index>>3]; \
+        } \
+    } \
+}
+
+/** Internal UTF-8 pre-decrement-previous: get the previous code point's data. */
+#define _UTRIE2_U8_PREV(trie, ascii, data, start, src, result) { \
+    uint8_t __b=(uint8_t)*--(src); \
+    if(__b<0x80) { \
+        (result)=(trie)->ascii[__b]; \
+    } else { \
+        int32_t __index=utrie2_internalU8PrevIndex((trie), __b, (const uint8_t *)(start), \
+                                                                (const uint8_t *)(src)); \
+        (src)-=__index&7; \
+        (result)=(trie)->data[__index>>3]; \
+    } \
+}
+
+U_CDECL_END
+
+/**
+ * Work around MSVC 2003 optimization bugs.
+ */
+#if defined (U_HAVE_MSVC_2003_OR_EARLIER)
+#pragma optimize("", off)
+#endif
+
+#endif