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1 /*
2 ******************************************************************************
3 *
4 *   Copyright (C) 2001-2006, International Business Machines
5 *   Corporation and others.  All Rights Reserved.
6 *
7 ******************************************************************************
8 *   file name:  utrie.h
9 *   encoding:   US-ASCII
10 *   tab size:   8 (not used)
11 *   indentation:4
12 *
13 *   created on: 2001nov08
14 *   created by: Markus W. Scherer
15 */
16 
17 #ifndef __UTRIE_H__
18 #define __UTRIE_H__
19 
20 #include "unicode/utypes.h"
21 #include "udataswp.h"
22 
23 U_CDECL_BEGIN
24 
25 /**
26  * \file
27  *
28  * This is a common implementation of a "folded" trie.
29  * It is a kind of compressed, serializable table of 16- or 32-bit values associated with
30  * Unicode code points (0..0x10ffff).
31  *
32  * This implementation is optimized for getting values while walking forward
33  * through a UTF-16 string.
34  * Therefore, the simplest and fastest access macros are the
35  * _FROM_LEAD() and _FROM_OFFSET_TRAIL() macros.
36  *
37  * The _FROM_BMP() macros are a little more complicated; they get values
38  * even for lead surrogate code _points_, while the _FROM_LEAD() macros
39  * get special "folded" values for lead surrogate code _units_ if
40  * there is relevant data associated with them.
41  * From such a folded value, an offset needs to be extracted to supply
42  * to the _FROM_OFFSET_TRAIL() macros.
43  *
44  * Most of the more complex (and more convenient) functions/macros call a callback function
45  * to get that offset from the folded value for a lead surrogate unit.
46  */
47 
48 /**
49  * Trie constants, defining shift widths, index array lengths, etc.
50  */
51 enum {
52     /** Shift size for shifting right the input index. 1..9 */
53     UTRIE_SHIFT=5,
54 
55     /** Number of data values in a stage 2 (data array) block. 2, 4, 8, .., 0x200 */
56     UTRIE_DATA_BLOCK_LENGTH=1<<UTRIE_SHIFT,
57 
58     /** Mask for getting the lower bits from the input index. */
59     UTRIE_MASK=UTRIE_DATA_BLOCK_LENGTH-1,
60 
61     /**
62      * Lead surrogate code points' index displacement in the index array.
63      * 0x10000-0xd800=0x2800
64      */
65     UTRIE_LEAD_INDEX_DISP=0x2800>>UTRIE_SHIFT,
66 
67     /**
68      * Shift size for shifting left the index array values.
69      * Increases possible data size with 16-bit index values at the cost
70      * of compactability.
71      * This requires blocks of stage 2 data to be aligned by UTRIE_DATA_GRANULARITY.
72      * 0..UTRIE_SHIFT
73      */
74     UTRIE_INDEX_SHIFT=2,
75 
76     /** The alignment size of a stage 2 data block. Also the granularity for compaction. */
77     UTRIE_DATA_GRANULARITY=1<<UTRIE_INDEX_SHIFT,
78 
79     /** Number of bits of a trail surrogate that are used in index table lookups. */
80     UTRIE_SURROGATE_BLOCK_BITS=10-UTRIE_SHIFT,
81 
82     /**
83      * Number of index (stage 1) entries per lead surrogate.
84      * Same as number of index entries for 1024 trail surrogates,
85      * ==0x400>>UTRIE_SHIFT
86      */
87     UTRIE_SURROGATE_BLOCK_COUNT=(1<<UTRIE_SURROGATE_BLOCK_BITS),
88 
89     /** Length of the BMP portion of the index (stage 1) array. */
90     UTRIE_BMP_INDEX_LENGTH=0x10000>>UTRIE_SHIFT
91 };
92 
93 /**
94  * Length of the index (stage 1) array before folding.
95  * Maximum number of Unicode code points (0x110000) shifted right by UTRIE_SHIFT.
96  */
97 #define UTRIE_MAX_INDEX_LENGTH (0x110000>>UTRIE_SHIFT)
98 
99 /**
100  * Maximum length of the runtime data (stage 2) array.
101  * Limited by 16-bit index values that are left-shifted by UTRIE_INDEX_SHIFT.
102  */
103 #define UTRIE_MAX_DATA_LENGTH (0x10000<<UTRIE_INDEX_SHIFT)
104 
105 /**
106  * Maximum length of the build-time data (stage 2) array.
107  * The maximum length is 0x110000+UTRIE_DATA_BLOCK_LENGTH+0x400.
108  * (Number of Unicode code points + one all-initial-value block +
109  *  possible duplicate entries for 1024 lead surrogates.)
110  */
111 #define UTRIE_MAX_BUILD_TIME_DATA_LENGTH (0x110000+UTRIE_DATA_BLOCK_LENGTH+0x400)
112 
113 /**
114  * Number of bytes for a dummy trie.
115  * A dummy trie is an empty runtime trie, used when a real data trie cannot
116  * be loaded.
117  * The number of bytes works for Latin-1-linear tries with 32-bit data
118  * (worst case).
119  *
120  * Calculation:
121  *   BMP index + 1 index block for lead surrogate code points +
122  *   Latin-1-linear array + 1 data block for lead surrogate code points
123  *
124  * Latin-1: if(UTRIE_SHIFT<=8) { 256 } else { included in first data block }
125  *
126  * @see utrie_unserializeDummy
127  */
128 #define UTRIE_DUMMY_SIZE ((UTRIE_BMP_INDEX_LENGTH+UTRIE_SURROGATE_BLOCK_COUNT)*2+(UTRIE_SHIFT<=8?256:UTRIE_DATA_BLOCK_LENGTH)*4+UTRIE_DATA_BLOCK_LENGTH*4)
129 
130 /**
131  * Runtime UTrie callback function.
132  * Extract from a lead surrogate's data the
133  * index array offset of the indexes for that lead surrogate.
134  *
135  * @param data data value for a surrogate from the trie, including the folding offset
136  * @return offset>=UTRIE_BMP_INDEX_LENGTH, or 0 if there is no data for the lead surrogate
137  */
138 typedef int32_t U_CALLCONV
139 UTrieGetFoldingOffset(uint32_t data);
140 
141 /**
142  * Run-time Trie structure.
143  *
144  * Either the data table is 16 bits wide and accessed via the index
145  * pointer, with each index item increased by indexLength;
146  * in this case, data32==NULL.
147  *
148  * Or the data table is 32 bits wide and accessed via the data32 pointer.
149  */
150 struct UTrie {
151     const uint16_t *index;
152     const uint32_t *data32; /* NULL if 16b data is used via index */
153 
154     /**
155      * This function is not used in _FROM_LEAD, _FROM_BMP, and _FROM_OFFSET_TRAIL macros.
156      * If convenience macros like _GET16 or _NEXT32 are used, this function must be set.
157      *
158      * utrie_unserialize() sets a default function which simply returns
159      * the lead surrogate's value itself - which is the inverse of the default
160      * folding function used by utrie_serialize().
161      *
162      * @see UTrieGetFoldingOffset
163      */
164     UTrieGetFoldingOffset *getFoldingOffset;
165 
166     int32_t indexLength, dataLength;
167     uint32_t initialValue;
168     UBool isLatin1Linear;
169 };
170 
171 typedef struct UTrie UTrie;
172 
173 /** Internal trie getter from an offset (0 if c16 is a BMP/lead units) and a 16-bit unit */
174 #define _UTRIE_GET_RAW(trie, data, offset, c16) \
175     (trie)->data[ \
176         ((int32_t)((trie)->index[(offset)+((c16)>>UTRIE_SHIFT)])<<UTRIE_INDEX_SHIFT)+ \
177         ((c16)&UTRIE_MASK) \
178     ]
179 
180 /** Internal trie getter from a pair of surrogates */
181 #define _UTRIE_GET_FROM_PAIR(trie, data, c, c2, result, resultType) { \
182     int32_t __offset; \
183 \
184     /* get data for lead surrogate */ \
185     (result)=_UTRIE_GET_RAW((trie), data, 0, (c)); \
186     __offset=(trie)->getFoldingOffset(result); \
187 \
188     /* get the real data from the folded lead/trail units */ \
189     if(__offset>0) { \
190         (result)=_UTRIE_GET_RAW((trie), data, __offset, (c2)&0x3ff); \
191     } else { \
192         (result)=(resultType)((trie)->initialValue); \
193     } \
194 }
195 
196 /** Internal trie getter from a BMP code point, treating a lead surrogate as a normal code point */
197 #define _UTRIE_GET_FROM_BMP(trie, data, c16) \
198     _UTRIE_GET_RAW(trie, data, 0xd800<=(c16) && (c16)<=0xdbff ? UTRIE_LEAD_INDEX_DISP : 0, c16);
199 
200 /**
201  * Internal trie getter from a code point.
202  * Could be faster(?) but longer with
203  *   if((c32)<=0xd7ff) { (result)=_UTRIE_GET_RAW(trie, data, 0, c32); }
204  */
205 #define _UTRIE_GET(trie, data, c32, result, resultType) \
206     if((uint32_t)(c32)<=0xffff) { \
207         /* BMP code points */ \
208         (result)=_UTRIE_GET_FROM_BMP(trie, data, c32); \
209     } else if((uint32_t)(c32)<=0x10ffff) { \
210         /* supplementary code point */ \
211         UChar __lead16=UTF16_LEAD(c32); \
212         _UTRIE_GET_FROM_PAIR(trie, data, __lead16, c32, result, resultType); \
213     } else { \
214         /* out of range */ \
215         (result)=(resultType)((trie)->initialValue); \
216     }
217 
218 /** Internal next-post-increment: get the next code point (c, c2) and its data */
219 #define _UTRIE_NEXT(trie, data, src, limit, c, c2, result, resultType) { \
220     (c)=*(src)++; \
221     if(!UTF_IS_LEAD(c)) { \
222         (c2)=0; \
223         (result)=_UTRIE_GET_RAW((trie), data, 0, (c)); \
224     } else if((src)!=(limit) && UTF_IS_TRAIL((c2)=*(src))) { \
225         ++(src); \
226         _UTRIE_GET_FROM_PAIR((trie), data, (c), (c2), (result), resultType); \
227     } else { \
228         /* unpaired lead surrogate code point */ \
229         (c2)=0; \
230         (result)=_UTRIE_GET_RAW((trie), data, UTRIE_LEAD_INDEX_DISP, (c)); \
231     } \
232 }
233 
234 /** Internal previous: get the previous code point (c, c2) and its data */
235 #define _UTRIE_PREVIOUS(trie, data, start, src, c, c2, result, resultType) { \
236     (c)=*--(src); \
237     if(!UTF_IS_SURROGATE(c)) { \
238         (c2)=0; \
239         (result)=_UTRIE_GET_RAW((trie), data, 0, (c)); \
240     } else if(!UTF_IS_SURROGATE_FIRST(c)) { \
241         /* trail surrogate */ \
242         if((start)!=(src) && UTF_IS_LEAD((c2)=*((src)-1))) { \
243             --(src); \
244             (result)=(c); (c)=(c2); (c2)=(UChar)(result); /* swap c, c2 */ \
245             _UTRIE_GET_FROM_PAIR((trie), data, (c), (c2), (result), resultType); \
246         } else { \
247             /* unpaired trail surrogate code point */ \
248             (c2)=0; \
249             (result)=_UTRIE_GET_RAW((trie), data, 0, (c)); \
250         } \
251     } else { \
252         /* unpaired lead surrogate code point */ \
253         (c2)=0; \
254         (result)=_UTRIE_GET_RAW((trie), data, UTRIE_LEAD_INDEX_DISP, (c)); \
255     } \
256 }
257 
258 /* Public UTrie API ---------------------------------------------------------*/
259 
260 /**
261  * Get a pointer to the contiguous part of the data array
262  * for the Latin-1 range (U+0000..U+00ff).
263  * Must be used only if the Latin-1 range is in fact linear
264  * (trie->isLatin1Linear).
265  *
266  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
267  * @return (const uint16_t *) pointer to values for Latin-1 code points
268  */
269 #define UTRIE_GET16_LATIN1(trie) ((trie)->index+(trie)->indexLength+UTRIE_DATA_BLOCK_LENGTH)
270 
271 /**
272  * Get a pointer to the contiguous part of the data array
273  * for the Latin-1 range (U+0000..U+00ff).
274  * Must be used only if the Latin-1 range is in fact linear
275  * (trie->isLatin1Linear).
276  *
277  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
278  * @return (const uint32_t *) pointer to values for Latin-1 code points
279  */
280 #define UTRIE_GET32_LATIN1(trie) ((trie)->data32+UTRIE_DATA_BLOCK_LENGTH)
281 
282 /**
283  * Get a 16-bit trie value from a BMP code point (UChar, <=U+ffff).
284  * c16 may be a lead surrogate, which may have a value including a folding offset.
285  *
286  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
287  * @param c16 (UChar, in) the input BMP code point
288  * @return (uint16_t) trie lookup result
289  */
290 #define UTRIE_GET16_FROM_LEAD(trie, c16) _UTRIE_GET_RAW(trie, index, 0, c16)
291 
292 /**
293  * Get a 32-bit trie value from a BMP code point (UChar, <=U+ffff).
294  * c16 may be a lead surrogate, which may have a value including a folding offset.
295  *
296  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
297  * @param c16 (UChar, in) the input BMP code point
298  * @return (uint32_t) trie lookup result
299  */
300 #define UTRIE_GET32_FROM_LEAD(trie, c16) _UTRIE_GET_RAW(trie, data32, 0, c16)
301 
302 /**
303  * Get a 16-bit trie value from a BMP code point (UChar, <=U+ffff).
304  * Even lead surrogate code points are treated as normal code points,
305  * with unfolded values that may differ from _FROM_LEAD() macro results for them.
306  *
307  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
308  * @param c16 (UChar, in) the input BMP code point
309  * @return (uint16_t) trie lookup result
310  */
311 #define UTRIE_GET16_FROM_BMP(trie, c16) _UTRIE_GET_FROM_BMP(trie, index, c16)
312 
313 /**
314  * Get a 32-bit trie value from a BMP code point (UChar, <=U+ffff).
315  * Even lead surrogate code points are treated as normal code points,
316  * with unfolded values that may differ from _FROM_LEAD() macro results for them.
317  *
318  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
319  * @param c16 (UChar, in) the input BMP code point
320  * @return (uint32_t) trie lookup result
321  */
322 #define UTRIE_GET32_FROM_BMP(trie, c16) _UTRIE_GET_FROM_BMP(trie, data32, c16)
323 
324 /**
325  * Get a 16-bit trie value from a code point.
326  * Even lead surrogate code points are treated as normal code points,
327  * with unfolded values that may differ from _FROM_LEAD() macro results for them.
328  *
329  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
330  * @param c32 (UChar32, in) the input code point
331  * @param result (uint16_t, out) uint16_t variable for the trie lookup result
332  */
333 #define UTRIE_GET16(trie, c32, result) _UTRIE_GET(trie, index, c32, result, uint16_t)
334 
335 /**
336  * Get a 32-bit trie value from a code point.
337  * Even lead surrogate code points are treated as normal code points,
338  * with unfolded values that may differ from _FROM_LEAD() macro results for them.
339  *
340  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
341  * @param c32 (UChar32, in) the input code point
342  * @param result (uint32_t, out) uint32_t variable for the trie lookup result
343  */
344 #define UTRIE_GET32(trie, c32, result) _UTRIE_GET(trie, data32, c32, result, uint32_t)
345 
346 /**
347  * Get the next code point (c, c2), post-increment src,
348  * and get a 16-bit value from the trie.
349  *
350  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
351  * @param src (const UChar *, in/out) the source text pointer
352  * @param limit (const UChar *, in) the limit pointer for the text, or NULL
353  * @param c (UChar, out) variable for the BMP or lead code unit
354  * @param c2 (UChar, out) variable for 0 or the trail code unit
355  * @param result (uint16_t, out) uint16_t variable for the trie lookup result
356  */
357 #define UTRIE_NEXT16(trie, src, limit, c, c2, result) _UTRIE_NEXT(trie, index, src, limit, c, c2, result, uint16_t)
358 
359 /**
360  * Get the next code point (c, c2), post-increment src,
361  * and get a 32-bit value from the trie.
362  *
363  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
364  * @param src (const UChar *, in/out) the source text pointer
365  * @param limit (const UChar *, in) the limit pointer for the text, or NULL
366  * @param c (UChar, out) variable for the BMP or lead code unit
367  * @param c2 (UChar, out) variable for 0 or the trail code unit
368  * @param result (uint32_t, out) uint32_t variable for the trie lookup result
369  */
370 #define UTRIE_NEXT32(trie, src, limit, c, c2, result) _UTRIE_NEXT(trie, data32, src, limit, c, c2, result, uint32_t)
371 
372 /**
373  * Get the previous code point (c, c2), pre-decrement src,
374  * and get a 16-bit value from the trie.
375  *
376  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
377  * @param start (const UChar *, in) the start pointer for the text, or NULL
378  * @param src (const UChar *, in/out) the source text pointer
379  * @param c (UChar, out) variable for the BMP or lead code unit
380  * @param c2 (UChar, out) variable for 0 or the trail code unit
381  * @param result (uint16_t, out) uint16_t variable for the trie lookup result
382  */
383 #define UTRIE_PREVIOUS16(trie, start, src, c, c2, result) _UTRIE_PREVIOUS(trie, index, start, src, c, c2, result, uint16_t)
384 
385 /**
386  * Get the previous code point (c, c2), pre-decrement src,
387  * and get a 32-bit value from the trie.
388  *
389  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
390  * @param start (const UChar *, in) the start pointer for the text, or NULL
391  * @param src (const UChar *, in/out) the source text pointer
392  * @param c (UChar, out) variable for the BMP or lead code unit
393  * @param c2 (UChar, out) variable for 0 or the trail code unit
394  * @param result (uint32_t, out) uint32_t variable for the trie lookup result
395  */
396 #define UTRIE_PREVIOUS32(trie, start, src, c, c2, result) _UTRIE_PREVIOUS(trie, data32, start, src, c, c2, result, uint32_t)
397 
398 /**
399  * Get a 16-bit trie value from a pair of surrogates.
400  *
401  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
402  * @param c (UChar, in) a lead surrogate
403  * @param c2 (UChar, in) a trail surrogate
404  * @param result (uint16_t, out) uint16_t variable for the trie lookup result
405  */
406 #define UTRIE_GET16_FROM_PAIR(trie, c, c2, result) _UTRIE_GET_FROM_PAIR(trie, index, c, c2, result, uint16_t)
407 
408 /**
409  * Get a 32-bit trie value from a pair of surrogates.
410  *
411  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
412  * @param c (UChar, in) a lead surrogate
413  * @param c2 (UChar, in) a trail surrogate
414  * @param result (uint32_t, out) uint32_t variable for the trie lookup result
415  */
416 #define UTRIE_GET32_FROM_PAIR(trie, c, c2, result) _UTRIE_GET_FROM_PAIR(trie, data32, c, c2, result, uint32_t)
417 
418 /**
419  * Get a 16-bit trie value from a folding offset (from the value of a lead surrogate)
420  * and a trail surrogate.
421  *
422  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
423  * @param offset (int32_t, in) the folding offset from the value of a lead surrogate
424  * @param c2 (UChar, in) a trail surrogate (only the 10 low bits are significant)
425  * @return (uint16_t) trie lookup result
426  */
427 #define UTRIE_GET16_FROM_OFFSET_TRAIL(trie, offset, c2) _UTRIE_GET_RAW(trie, index, offset, (c2)&0x3ff)
428 
429 /**
430  * Get a 32-bit trie value from a folding offset (from the value of a lead surrogate)
431  * and a trail surrogate.
432  *
433  * @param trie (const UTrie *, in) a pointer to the runtime trie structure
434  * @param offset (int32_t, in) the folding offset from the value of a lead surrogate
435  * @param c2 (UChar, in) a trail surrogate (only the 10 low bits are significant)
436  * @return (uint32_t) trie lookup result
437  */
438 #define UTRIE_GET32_FROM_OFFSET_TRAIL(trie, offset, c2) _UTRIE_GET_RAW(trie, data32, offset, (c2)&0x3ff)
439 
440 /* enumeration callback types */
441 
442 /**
443  * Callback from utrie_enum(), extracts a uint32_t value from a
444  * trie value. This value will be passed on to the UTrieEnumRange function.
445  *
446  * @param context an opaque pointer, as passed into utrie_enum()
447  * @param value a value from the trie
448  * @return the value that is to be passed on to the UTrieEnumRange function
449  */
450 typedef uint32_t U_CALLCONV
451 UTrieEnumValue(const void *context, uint32_t value);
452 
453 /**
454  * Callback from utrie_enum(), is called for each contiguous range
455  * of code points with the same value as retrieved from the trie and
456  * transformed by the UTrieEnumValue function.
457  *
458  * The callback function can stop the enumeration by returning FALSE.
459  *
460  * @param context an opaque pointer, as passed into utrie_enum()
461  * @param start the first code point in a contiguous range with value
462  * @param limit one past the last code point in a contiguous range with value
463  * @param value the value that is set for all code points in [start..limit[
464  * @return FALSE to stop the enumeration
465  */
466 typedef UBool U_CALLCONV
467 UTrieEnumRange(const void *context, UChar32 start, UChar32 limit, uint32_t value);
468 
469 /**
470  * Enumerate efficiently all values in a trie.
471  * For each entry in the trie, the value to be delivered is passed through
472  * the UTrieEnumValue function.
473  * The value is unchanged if that function pointer is NULL.
474  *
475  * For each contiguous range of code points with a given value,
476  * the UTrieEnumRange function is called.
477  *
478  * @param trie a pointer to the runtime trie structure
479  * @param enumValue a pointer to a function that may transform the trie entry value,
480  *                  or NULL if the values from the trie are to be used directly
481  * @param enumRange a pointer to a function that is called for each contiguous range
482  *                  of code points with the same value
483  * @param context an opaque pointer that is passed on to the callback functions
484  */
485 U_CAPI void U_EXPORT2
486 utrie_enum(const UTrie *trie,
487            UTrieEnumValue *enumValue, UTrieEnumRange *enumRange, const void *context);
488 
489 /**
490  * Unserialize a trie from 32-bit-aligned memory.
491  * Inverse of utrie_serialize().
492  * Fills the UTrie runtime trie structure with the settings for the trie data.
493  *
494  * @param trie a pointer to the runtime trie structure
495  * @param data a pointer to 32-bit-aligned memory containing trie data
496  * @param length the number of bytes available at data
497  * @param pErrorCode an in/out ICU UErrorCode
498  * @return the number of bytes at data taken up by the trie data
499  */
500 U_CAPI int32_t U_EXPORT2
501 utrie_unserialize(UTrie *trie, const void *data, int32_t length, UErrorCode *pErrorCode);
502 
503 /**
504  * "Unserialize" a dummy trie.
505  * A dummy trie is an empty runtime trie, used when a real data trie cannot
506  * be loaded.
507  *
508  * The input memory is filled so that the trie always returns the initialValue,
509  * or the leadUnitValue for lead surrogate code points.
510  * The Latin-1 part is always set up to be linear.
511  *
512  * @param trie a pointer to the runtime trie structure
513  * @param data a pointer to 32-bit-aligned memory to be filled with the dummy trie data
514  * @param length the number of bytes available at data (recommended to use UTRIE_DUMMY_SIZE)
515  * @param initialValue the initial value that is set for all code points
516  * @param leadUnitValue the value for lead surrogate code _units_ that do not
517  *                      have associated supplementary data
518  * @param pErrorCode an in/out ICU UErrorCode
519  *
520  * @see UTRIE_DUMMY_SIZE
521  * @see utrie_open
522  */
523 U_CAPI int32_t U_EXPORT2
524 utrie_unserializeDummy(UTrie *trie,
525                        void *data, int32_t length,
526                        uint32_t initialValue, uint32_t leadUnitValue,
527                        UBool make16BitTrie,
528                        UErrorCode *pErrorCode);
529 
530 /**
531  * Default implementation for UTrie.getFoldingOffset, set automatically by
532  * utrie_unserialize().
533  * Simply returns the lead surrogate's value itself - which is the inverse
534  * of the default folding function used by utrie_serialize().
535  * Exported for static const UTrie structures.
536  *
537  * @see UTrieGetFoldingOffset
538  */
539 U_CAPI int32_t U_EXPORT2
540 utrie_defaultGetFoldingOffset(uint32_t data);
541 
542 /* Building a trie ----------------------------------------------------------*/
543 
544 /**
545  * Build-time trie structure.
546  * Opaque definition, here only to make fillIn parameters possible
547  * for utrie_open() and utrie_clone().
548  */
549 struct UNewTrie {
550     /**
551      * Index values at build-time are 32 bits wide for easier processing.
552      * Bit 31 is set if the data block is used by multiple index values (from utrie_setRange()).
553      */
554     int32_t index[UTRIE_MAX_INDEX_LENGTH];
555     uint32_t *data;
556 
557     uint32_t leadUnitValue;
558     int32_t indexLength, dataCapacity, dataLength;
559     UBool isAllocated, isDataAllocated;
560     UBool isLatin1Linear, isCompacted;
561 
562     /**
563      * Map of adjusted indexes, used in utrie_compact().
564      * Maps from original indexes to new ones.
565      */
566     int32_t map[UTRIE_MAX_BUILD_TIME_DATA_LENGTH>>UTRIE_SHIFT];
567 };
568 
569 typedef struct UNewTrie UNewTrie;
570 
571 /**
572  * Build-time trie callback function, used with utrie_serialize().
573  * This function calculates a lead surrogate's value including a folding offset
574  * from the 1024 supplementary code points [start..start+1024[ .
575  * It is U+10000 <= start <= U+10fc00 and (start&0x3ff)==0.
576  *
577  * The folding offset is provided by the caller.
578  * It is offset=UTRIE_BMP_INDEX_LENGTH+n*UTRIE_SURROGATE_BLOCK_COUNT with n=0..1023.
579  * Instead of the offset itself, n can be stored in 10 bits -
580  * or fewer if it can be assumed that few lead surrogates have associated data.
581  *
582  * The returned value must be
583  * - not zero if and only if there is relevant data
584  *   for the corresponding 1024 supplementary code points
585  * - such that UTrie.getFoldingOffset(UNewTrieGetFoldedValue(..., offset))==offset
586  *
587  * @return a folded value, or 0 if there is no relevant data for the lead surrogate.
588  */
589 typedef uint32_t U_CALLCONV
590 UNewTrieGetFoldedValue(UNewTrie *trie, UChar32 start, int32_t offset);
591 
592 /**
593  * Open a build-time trie structure.
594  * The size of the build-time data array is specified to avoid allocating a large
595  * array in all cases. The array itself can also be passed in.
596  *
597  * Although the trie is never fully expanded to a linear array, especially when
598  * utrie_setRange32() is used, the data array could be large during build time.
599  * The maximum length is
600  * UTRIE_MAX_BUILD_TIME_DATA_LENGTH=0x110000+UTRIE_DATA_BLOCK_LENGTH+0x400.
601  * (Number of Unicode code points + one all-initial-value block +
602  *  possible duplicate entries for 1024 lead surrogates.)
603  * (UTRIE_DATA_BLOCK_LENGTH<=0x200 in all cases.)
604  *
605  * @param fillIn a pointer to a UNewTrie structure to be initialized (will not be released), or
606  *               NULL if one is to be allocated
607  * @param aliasData a pointer to a data array to be used (will not be released), or
608  *                  NULL if one is to be allocated
609  * @param maxDataLength the capacity of aliasData (if not NULL) or
610  *                      the length of the data array to be allocated
611  * @param initialValue the initial value that is set for all code points
612  * @param leadUnitValue the value for lead surrogate code _units_ that do not
613  *                      have associated supplementary data
614  * @param latin1Linear a flag indicating whether the Latin-1 range is to be allocated and
615  *                     kept in a linear, contiguous part of the data array
616  * @return a pointer to the initialized fillIn or the allocated and initialized new UNewTrie
617  */
618 U_CAPI UNewTrie * U_EXPORT2
619 utrie_open(UNewTrie *fillIn,
620            uint32_t *aliasData, int32_t maxDataLength,
621            uint32_t initialValue, uint32_t leadUnitValue,
622            UBool latin1Linear);
623 
624 /**
625  * Clone a build-time trie structure with all entries.
626  *
627  * @param fillIn like in utrie_open()
628  * @param other the build-time trie structure to clone
629  * @param aliasData like in utrie_open(),
630  *                  used if aliasDataLength>=(capacity of other's data array)
631  * @param aliasDataLength the length of aliasData
632  * @return a pointer to the initialized fillIn or the allocated and initialized new UNewTrie
633  */
634 U_CAPI UNewTrie * U_EXPORT2
635 utrie_clone(UNewTrie *fillIn, const UNewTrie *other, uint32_t *aliasData, int32_t aliasDataLength);
636 
637 /**
638  * Close a build-time trie structure, and release memory
639  * that was allocated by utrie_open() or utrie_clone().
640  *
641  * @param trie the build-time trie
642  */
643 U_CAPI void U_EXPORT2
644 utrie_close(UNewTrie *trie);
645 
646 /**
647  * Get the data array of a build-time trie.
648  * The data may be modified, but entries that are equal before
649  * must still be equal after modification.
650  *
651  * @param trie the build-time trie
652  * @param pLength (out) a pointer to a variable that receives the number
653  *                of entries in the data array
654  * @return the data array
655  */
656 U_CAPI uint32_t * U_EXPORT2
657 utrie_getData(UNewTrie *trie, int32_t *pLength);
658 
659 /**
660  * Set a value for a code point.
661  *
662  * @param trie the build-time trie
663  * @param c the code point
664  * @param value the value
665  * @return FALSE if a failure occurred (illegal argument or data array overrun)
666  */
667 U_CAPI UBool U_EXPORT2
668 utrie_set32(UNewTrie *trie, UChar32 c, uint32_t value);
669 
670 /**
671  * Get a value from a code point as stored in the build-time trie.
672  *
673  * @param trie the build-time trie
674  * @param c the code point
675  * @param pInBlockZero if not NULL, then *pInBlockZero is set to TRUE
676  *                     iff the value is retrieved from block 0;
677  *                     block 0 is the all-initial-value initial block
678  * @return the value
679  */
680 U_CAPI uint32_t U_EXPORT2
681 utrie_get32(UNewTrie *trie, UChar32 c, UBool *pInBlockZero);
682 
683 /**
684  * Set a value in a range of code points [start..limit[.
685  * All code points c with start<=c<limit will get the value if
686  * overwrite is TRUE or if the old value is 0.
687  *
688  * @param trie the build-time trie
689  * @param start the first code point to get the value
690  * @param limit one past the last code point to get the value
691  * @param value the value
692  * @param overwrite flag for whether old non-initial values are to be overwritten
693  * @return FALSE if a failure occurred (illegal argument or data array overrun)
694  */
695 U_CAPI UBool U_EXPORT2
696 utrie_setRange32(UNewTrie *trie, UChar32 start, UChar32 limit, uint32_t value, UBool overwrite);
697 
698 /**
699  * Compact the build-time trie after all values are set, and then
700  * serialize it into 32-bit aligned memory.
701  *
702  * After this, the trie can only be serizalized again and/or closed;
703  * no further values can be added.
704  *
705  * @see utrie_unserialize()
706  *
707  * @param trie the build-time trie
708  * @param data a pointer to 32-bit-aligned memory for the trie data
709  * @param capacity the number of bytes available at data
710  * @param getFoldedValue a callback function that calculates the value for
711  *                       a lead surrogate from all of its supplementary code points
712  *                       and the folding offset;
713  *                       if NULL, then a default function is used which returns just
714  *                       the input offset when there are any non-initial-value entries
715  * @param reduceTo16Bits flag for whether the values are to be reduced to a
716  *                       width of 16 bits for serialization and runtime
717  * @param pErrorCode a UErrorCode argument; among other possible error codes:
718  * - U_BUFFER_OVERFLOW_ERROR if the data storage block is too small for serialization
719  * - U_MEMORY_ALLOCATION_ERROR if the trie data array is too small
720  * - U_INDEX_OUTOFBOUNDS_ERROR if the index or data arrays are too long after compaction for serialization
721  *
722  * @return the number of bytes written for the trie
723  */
724 U_CAPI int32_t U_EXPORT2
725 utrie_serialize(UNewTrie *trie, void *data, int32_t capacity,
726                 UNewTrieGetFoldedValue *getFoldedValue,
727                 UBool reduceTo16Bits,
728                 UErrorCode *pErrorCode);
729 
730 /**
731  * Swap a serialized UTrie.
732  * @internal
733  */
734 U_CAPI int32_t U_EXPORT2
735 utrie_swap(const UDataSwapper *ds,
736            const void *inData, int32_t length, void *outData,
737            UErrorCode *pErrorCode);
738 
739 /* serialization ------------------------------------------------------------ */
740 
741 /**
742  * Trie data structure in serialized form:
743  *
744  * UTrieHeader header;
745  * uint16_t index[header.indexLength];
746  * uint16_t data[header.dataLength];
747  * @internal
748  */
749 typedef struct UTrieHeader {
750     /** "Trie" in big-endian US-ASCII (0x54726965) */
751     uint32_t signature;
752 
753     /**
754      * options bit field:
755      *     9    1=Latin-1 data is stored linearly at data+UTRIE_DATA_BLOCK_LENGTH
756      *     8    0=16-bit data, 1=32-bit data
757      *  7..4    UTRIE_INDEX_SHIFT   // 0..UTRIE_SHIFT
758      *  3..0    UTRIE_SHIFT         // 1..9
759      */
760     uint32_t options;
761 
762     /** indexLength is a multiple of UTRIE_SURROGATE_BLOCK_COUNT */
763     int32_t indexLength;
764 
765     /** dataLength>=UTRIE_DATA_BLOCK_LENGTH */
766     int32_t dataLength;
767 } UTrieHeader;
768 
769 /**
770  * Constants for use with UTrieHeader.options.
771  * @internal
772  */
773 enum {
774     /** Mask to get the UTRIE_SHIFT value from options. */
775     UTRIE_OPTIONS_SHIFT_MASK=0xf,
776 
777     /** Shift options right this much to get the UTRIE_INDEX_SHIFT value. */
778     UTRIE_OPTIONS_INDEX_SHIFT=4,
779 
780     /** If set, then the data (stage 2) array is 32 bits wide. */
781     UTRIE_OPTIONS_DATA_IS_32_BIT=0x100,
782 
783     /**
784      * If set, then Latin-1 data (for U+0000..U+00ff) is stored in the data (stage 2) array
785      * as a simple, linear array at data+UTRIE_DATA_BLOCK_LENGTH.
786      */
787     UTRIE_OPTIONS_LATIN1_IS_LINEAR=0x200
788 };
789 
790 U_CDECL_END
791 
792 #endif
793