summaryrefslogtreecommitdiffstats
path: root/intl/icu/source/common/ucnvhz.c
blob: d35551628b03982c120fecfd8cdca69a8bd120c9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
// Copyright (C) 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*  
**********************************************************************
*   Copyright (C) 2000-2015, International Business Machines
*   Corporation and others.  All Rights Reserved.
**********************************************************************
*   file name:  ucnvhz.c
*   encoding:   US-ASCII
*   tab size:   8 (not used)
*   indentation:4
*
*   created on: 2000oct16
*   created by: Ram Viswanadha
*   10/31/2000  Ram     Implemented offsets logic function
*   
*/

#include "unicode/utypes.h"

#if !UCONFIG_NO_CONVERSION && !UCONFIG_NO_LEGACY_CONVERSION && !UCONFIG_ONLY_HTML_CONVERSION

#include "cmemory.h"
#include "unicode/ucnv.h"
#include "unicode/ucnv_cb.h"
#include "unicode/uset.h"
#include "unicode/utf16.h"
#include "ucnv_bld.h"
#include "ucnv_cnv.h"
#include "ucnv_imp.h"

#define UCNV_TILDE 0x7E          /* ~ */
#define UCNV_OPEN_BRACE 0x7B     /* { */
#define UCNV_CLOSE_BRACE 0x7D   /* } */
#define SB_ESCAPE    "\x7E\x7D"
#define DB_ESCAPE    "\x7E\x7B"
#define TILDE_ESCAPE "\x7E\x7E"
#define ESC_LEN       2


#define CONCAT_ESCAPE_MACRO( args, targetIndex,targetLength,strToAppend, err, len,sourceIndex){                             \
    while(len-->0){                                                                                                         \
        if(targetIndex < targetLength){                                                                                     \
            args->target[targetIndex] = (unsigned char) *strToAppend;                                                       \
            if(args->offsets!=NULL){                                                                                        \
                *(offsets++) = sourceIndex-1;                                                                               \
            }                                                                                                               \
            targetIndex++;                                                                                                  \
        }                                                                                                                   \
        else{                                                                                                               \
            args->converter->charErrorBuffer[(int)args->converter->charErrorBufferLength++] = (unsigned char) *strToAppend; \
            *err =U_BUFFER_OVERFLOW_ERROR;                                                                                  \
        }                                                                                                                   \
        strToAppend++;                                                                                                      \
    }                                                                                                                       \
}


typedef struct{
    UConverter* gbConverter;
    int32_t targetIndex;
    int32_t sourceIndex;
    UBool isEscapeAppended;
    UBool isStateDBCS;
    UBool isTargetUCharDBCS;
    UBool isEmptySegment;
}UConverterDataHZ;



static void 
_HZOpen(UConverter *cnv, UConverterLoadArgs *pArgs, UErrorCode *errorCode){
    UConverter *gbConverter;
    if(pArgs->onlyTestIsLoadable) {
        ucnv_canCreateConverter("GBK", errorCode);  /* errorCode carries result */
        return;
    }
    gbConverter = ucnv_open("GBK", errorCode);
    if(U_FAILURE(*errorCode)) {
        return;
    }
    cnv->toUnicodeStatus = 0;
    cnv->fromUnicodeStatus= 0;
    cnv->mode=0;
    cnv->fromUChar32=0x0000;
    cnv->extraInfo = uprv_calloc(1, sizeof(UConverterDataHZ));
    if(cnv->extraInfo != NULL){
        ((UConverterDataHZ*)cnv->extraInfo)->gbConverter = gbConverter;
    }
    else {
        ucnv_close(gbConverter);
        *errorCode = U_MEMORY_ALLOCATION_ERROR;
        return;
    }
}

static void 
_HZClose(UConverter *cnv){
    if(cnv->extraInfo != NULL) {
        ucnv_close (((UConverterDataHZ *) (cnv->extraInfo))->gbConverter);
        if(!cnv->isExtraLocal) {
            uprv_free(cnv->extraInfo);
        }
        cnv->extraInfo = NULL;
    }
}

static void 
_HZReset(UConverter *cnv, UConverterResetChoice choice){
    if(choice<=UCNV_RESET_TO_UNICODE) {
        cnv->toUnicodeStatus = 0;
        cnv->mode=0;
        if(cnv->extraInfo != NULL){
            ((UConverterDataHZ*)cnv->extraInfo)->isStateDBCS = FALSE;
            ((UConverterDataHZ*)cnv->extraInfo)->isEmptySegment = FALSE;
        }
    }
    if(choice!=UCNV_RESET_TO_UNICODE) {
        cnv->fromUnicodeStatus= 0;
        cnv->fromUChar32=0x0000; 
        if(cnv->extraInfo != NULL){
            ((UConverterDataHZ*)cnv->extraInfo)->isEscapeAppended = FALSE;
            ((UConverterDataHZ*)cnv->extraInfo)->targetIndex = 0;
            ((UConverterDataHZ*)cnv->extraInfo)->sourceIndex = 0;
            ((UConverterDataHZ*)cnv->extraInfo)->isTargetUCharDBCS = FALSE;
        }
    }
}

/**************************************HZ Encoding*************************************************
* Rules for HZ encoding
* 
*   In ASCII mode, a byte is interpreted as an ASCII character, unless a
*   '~' is encountered. The character '~' is an escape character. By
*   convention, it must be immediately followed ONLY by '~', '{' or '\n'
*   (<LF>), with the following special meaning.

*   1. The escape sequence '~~' is interpreted as a '~'.
*   2. The escape-to-GB sequence '~{' switches the mode from ASCII to GB.
*   3. The escape sequence '~\n' is a line-continuation marker to be
*     consumed with no output produced.
*   In GB mode, characters are interpreted two bytes at a time as (pure)
*   GB codes until the escape-from-GB code '~}' is read. This code
*   switches the mode from GB back to ASCII.  (Note that the escape-
*   from-GB code '~}' ($7E7D) is outside the defined GB range.)
*
*   Source: RFC 1842
*
*   Note that the formal syntax in RFC 1842 is invalid. I assume that the
*   intended definition of single-byte-segment is as follows (pedberg):
*   single-byte-segment = single-byte-seq 1*single-byte-char
*/


static void 
UConverter_toUnicode_HZ_OFFSETS_LOGIC(UConverterToUnicodeArgs *args,
                                                            UErrorCode* err){
    char tempBuf[2];
    const char *mySource = ( char *) args->source;
    UChar *myTarget = args->target;
    const char *mySourceLimit = args->sourceLimit;
    UChar32 targetUniChar = 0x0000;
    int32_t mySourceChar = 0x0000;
    UConverterDataHZ* myData=(UConverterDataHZ*)(args->converter->extraInfo);
    tempBuf[0]=0; 
    tempBuf[1]=0;

    /* Calling code already handles this situation. */
    /*if ((args->converter == NULL) || (args->targetLimit < args->target) || (mySourceLimit < args->source)){
        *err = U_ILLEGAL_ARGUMENT_ERROR;
        return;
    }*/
    
    while(mySource< mySourceLimit){
        
        if(myTarget < args->targetLimit){
            
            mySourceChar= (unsigned char) *mySource++;

            if(args->converter->mode == UCNV_TILDE) {
                /* second byte after ~ */
                args->converter->mode=0;
                switch(mySourceChar) {
                case 0x0A:
                    /* no output for ~\n (line-continuation marker) */
                    continue;
                case UCNV_TILDE:
                    if(args->offsets) {
                        args->offsets[myTarget - args->target]=(int32_t)(mySource - args->source - 2);
                    }
                    *(myTarget++)=(UChar)mySourceChar;
                    myData->isEmptySegment = FALSE;
                    continue;
                case UCNV_OPEN_BRACE:
                case UCNV_CLOSE_BRACE:
                    myData->isStateDBCS = (mySourceChar == UCNV_OPEN_BRACE);
                    if (myData->isEmptySegment) {
                        myData->isEmptySegment = FALSE; /* we are handling it, reset to avoid future spurious errors */
                        *err = U_ILLEGAL_ESCAPE_SEQUENCE;
                        args->converter->toUCallbackReason = UCNV_IRREGULAR;
                        args->converter->toUBytes[0] = UCNV_TILDE;
                        args->converter->toUBytes[1] = mySourceChar;
                        args->converter->toULength = 2;
                        args->target = myTarget;
                        args->source = mySource;
                        return;
                    }
                    myData->isEmptySegment = TRUE;
                    continue;
                default:
                     /* if the first byte is equal to TILDE and the trail byte
                     * is not a valid byte then it is an error condition
                     */
                    /*
                     * Ticket 5691: consistent illegal sequences:
                     * - We include at least the first byte in the illegal sequence.
                     * - If any of the non-initial bytes could be the start of a character,
                     *   we stop the illegal sequence before the first one of those.
                     */
                    myData->isEmptySegment = FALSE; /* different error here, reset this to avoid spurious future error */
                    *err = U_ILLEGAL_ESCAPE_SEQUENCE;
                    args->converter->toUBytes[0] = UCNV_TILDE;
                    if( myData->isStateDBCS ?
                            (0x21 <= mySourceChar && mySourceChar <= 0x7e) :
                            mySourceChar <= 0x7f
                    ) {
                        /* The current byte could be the start of a character: Back it out. */
                        args->converter->toULength = 1;
                        --mySource;
                    } else {
                        /* Include the current byte in the illegal sequence. */
                        args->converter->toUBytes[1] = mySourceChar;
                        args->converter->toULength = 2;
                    }
                    args->target = myTarget;
                    args->source = mySource;
                    return;
                }
            } else if(myData->isStateDBCS) {
                if(args->converter->toUnicodeStatus == 0x00){
                    /* lead byte */
                    if(mySourceChar == UCNV_TILDE) {
                        args->converter->mode = UCNV_TILDE;
                    } else {
                        /* add another bit to distinguish a 0 byte from not having seen a lead byte */
                        args->converter->toUnicodeStatus = (uint32_t) (mySourceChar | 0x100);
                        myData->isEmptySegment = FALSE; /* the segment has something, either valid or will produce a different error, so reset this */
                    }
                    continue;
                }
                else{
                    /* trail byte */
                    int leadIsOk, trailIsOk;
                    uint32_t leadByte = args->converter->toUnicodeStatus & 0xff;
                    targetUniChar = 0xffff;
                    /*
                     * Ticket 5691: consistent illegal sequences:
                     * - We include at least the first byte in the illegal sequence.
                     * - If any of the non-initial bytes could be the start of a character,
                     *   we stop the illegal sequence before the first one of those.
                     *
                     * In HZ DBCS, if the second byte is in the 21..7e range,
                     * we report only the first byte as the illegal sequence.
                     * Otherwise we convert or report the pair of bytes.
                     */
                    leadIsOk = (uint8_t)(leadByte - 0x21) <= (0x7d - 0x21);
                    trailIsOk = (uint8_t)(mySourceChar - 0x21) <= (0x7e - 0x21);
                    if (leadIsOk && trailIsOk) {
                        tempBuf[0] = (char) (leadByte+0x80) ;
                        tempBuf[1] = (char) (mySourceChar+0x80);
                        targetUniChar = ucnv_MBCSSimpleGetNextUChar(myData->gbConverter->sharedData,
                            tempBuf, 2, args->converter->useFallback);
                        mySourceChar= (leadByte << 8) | mySourceChar;
                    } else if (trailIsOk) {
                        /* report a single illegal byte and continue with the following DBCS starter byte */
                        --mySource;
                        mySourceChar = (int32_t)leadByte;
                    } else {
                        /* report a pair of illegal bytes if the second byte is not a DBCS starter */
                        /* add another bit so that the code below writes 2 bytes in case of error */
                        mySourceChar= 0x10000 | (leadByte << 8) | mySourceChar;
                    }
                    args->converter->toUnicodeStatus =0x00;
                }
            }
            else{
                if(mySourceChar == UCNV_TILDE) {
                    args->converter->mode = UCNV_TILDE;
                    continue;
                } else if(mySourceChar <= 0x7f) {
                    targetUniChar = (UChar)mySourceChar;  /* ASCII */
                    myData->isEmptySegment = FALSE; /* the segment has something valid */
                } else {
                    targetUniChar = 0xffff;
                    myData->isEmptySegment = FALSE; /* different error here, reset this to avoid spurious future error */
                }
            }
            if(targetUniChar < 0xfffe){
                if(args->offsets) {
                    args->offsets[myTarget - args->target]=(int32_t)(mySource - args->source - 1-(myData->isStateDBCS));
                }

                *(myTarget++)=(UChar)targetUniChar;
            }
            else /* targetUniChar>=0xfffe */ {
                if(targetUniChar == 0xfffe){
                    *err = U_INVALID_CHAR_FOUND;
                }
                else{
                    *err = U_ILLEGAL_CHAR_FOUND;
                }
                if(mySourceChar > 0xff){
                    args->converter->toUBytes[0] = (uint8_t)(mySourceChar >> 8);
                    args->converter->toUBytes[1] = (uint8_t)mySourceChar;
                    args->converter->toULength=2;
                }
                else{
                    args->converter->toUBytes[0] = (uint8_t)mySourceChar;
                    args->converter->toULength=1;
                }
                break;
            }
        }
        else{
            *err =U_BUFFER_OVERFLOW_ERROR;
            break;
        }
    }

    args->target = myTarget;
    args->source = mySource;
}


static void 
UConverter_fromUnicode_HZ_OFFSETS_LOGIC (UConverterFromUnicodeArgs * args,
                                                      UErrorCode * err){
    const UChar *mySource = args->source;
    char *myTarget = args->target;
    int32_t* offsets = args->offsets;
    int32_t mySourceIndex = 0;
    int32_t myTargetIndex = 0;
    int32_t targetLength = (int32_t)(args->targetLimit - myTarget);
    int32_t mySourceLength = (int32_t)(args->sourceLimit - args->source);
    uint32_t targetUniChar = 0x0000;
    UChar32 mySourceChar = 0x0000;
    UConverterDataHZ *myConverterData=(UConverterDataHZ*)args->converter->extraInfo;
    UBool isTargetUCharDBCS = (UBool) myConverterData->isTargetUCharDBCS;
    UBool oldIsTargetUCharDBCS;
    int len =0;
    const char* escSeq=NULL;
    
    /* Calling code already handles this situation. */
    /*if ((args->converter == NULL) || (args->targetLimit < myTarget) || (args->sourceLimit < args->source)){
        *err = U_ILLEGAL_ARGUMENT_ERROR;
        return;
    }*/
    if(args->converter->fromUChar32!=0 && myTargetIndex < targetLength) {
        goto getTrail;
    }
    /*writing the char to the output stream */
    while (mySourceIndex < mySourceLength){
        targetUniChar = missingCharMarker;
        if (myTargetIndex < targetLength){
            
            mySourceChar = (UChar) mySource[mySourceIndex++];
            

            oldIsTargetUCharDBCS = isTargetUCharDBCS;
            if(mySourceChar ==UCNV_TILDE){
                /*concatEscape(args, &myTargetIndex, &targetLength,"\x7E\x7E",err,2,&mySourceIndex);*/
                len = ESC_LEN;
                escSeq = TILDE_ESCAPE;
                CONCAT_ESCAPE_MACRO(args, myTargetIndex, targetLength, escSeq,err,len,mySourceIndex);
                continue;
            } else if(mySourceChar <= 0x7f) {
                targetUniChar = mySourceChar;
            } else {
                int32_t length= ucnv_MBCSFromUChar32(myConverterData->gbConverter->sharedData,
                    mySourceChar,&targetUniChar,args->converter->useFallback);
                /* we can only use lead bytes 21..7D and trail bytes 21..7E */
                if( length == 2 &&
                    (uint16_t)(targetUniChar - 0xa1a1) <= (0xfdfe - 0xa1a1) &&
                    (uint8_t)(targetUniChar - 0xa1) <= (0xfe - 0xa1)
                ) {
                    targetUniChar -= 0x8080;
                } else {
                    targetUniChar = missingCharMarker;
                }
            }
            if (targetUniChar != missingCharMarker){
               myConverterData->isTargetUCharDBCS = isTargetUCharDBCS = (UBool)(targetUniChar>0x00FF);     
                 if(oldIsTargetUCharDBCS != isTargetUCharDBCS || !myConverterData->isEscapeAppended ){
                    /*Shifting from a double byte to single byte mode*/
                    if(!isTargetUCharDBCS){
                        len =ESC_LEN;
                        escSeq = SB_ESCAPE;
                        CONCAT_ESCAPE_MACRO(args, myTargetIndex, targetLength, escSeq,err,len,mySourceIndex);
                        myConverterData->isEscapeAppended = TRUE;
                    }
                    else{ /* Shifting from a single byte to double byte mode*/
                        len =ESC_LEN;
                        escSeq = DB_ESCAPE;
                        CONCAT_ESCAPE_MACRO(args, myTargetIndex, targetLength, escSeq,err,len,mySourceIndex);
                        myConverterData->isEscapeAppended = TRUE;
                        
                    }
                }
            
                if(isTargetUCharDBCS){
                    if( myTargetIndex <targetLength){
                        myTarget[myTargetIndex++] =(char) (targetUniChar >> 8);
                        if(offsets){
                            *(offsets++) = mySourceIndex-1;
                        }
                        if(myTargetIndex < targetLength){
                            myTarget[myTargetIndex++] =(char) targetUniChar;
                            if(offsets){
                                *(offsets++) = mySourceIndex-1;
                            }
                        }else{
                            args->converter->charErrorBuffer[args->converter->charErrorBufferLength++] = (char) targetUniChar;
                            *err = U_BUFFER_OVERFLOW_ERROR;
                        } 
                    }else{
                        args->converter->charErrorBuffer[args->converter->charErrorBufferLength++] =(char) (targetUniChar >> 8);
                        args->converter->charErrorBuffer[args->converter->charErrorBufferLength++] = (char) targetUniChar;
                        *err = U_BUFFER_OVERFLOW_ERROR;
                    }

                }else{
                    if( myTargetIndex <targetLength){
                        myTarget[myTargetIndex++] = (char) (targetUniChar );
                        if(offsets){
                            *(offsets++) = mySourceIndex-1;
                        }
                        
                    }else{
                        args->converter->charErrorBuffer[args->converter->charErrorBufferLength++] = (char) targetUniChar;
                        *err = U_BUFFER_OVERFLOW_ERROR;
                    }
                }

            }
            else{
                /* oops.. the code point is unassigned */
                /*Handle surrogates */
                /*check if the char is a First surrogate*/
                if(U16_IS_SURROGATE(mySourceChar)) {
                    if(U16_IS_SURROGATE_LEAD(mySourceChar)) {
                        args->converter->fromUChar32=mySourceChar;
getTrail:
                        /*look ahead to find the trail surrogate*/
                        if(mySourceIndex <  mySourceLength) {
                            /* test the following code unit */
                            UChar trail=(UChar) args->source[mySourceIndex];
                            if(U16_IS_TRAIL(trail)) {
                                ++mySourceIndex;
                                mySourceChar=U16_GET_SUPPLEMENTARY(args->converter->fromUChar32, trail);
                                args->converter->fromUChar32=0x00;
                                /* there are no surrogates in GB2312*/
                                *err = U_INVALID_CHAR_FOUND;
                                /* exit this condition tree */
                            } else {
                                /* this is an unmatched lead code unit (1st surrogate) */
                                /* callback(illegal) */
                                *err=U_ILLEGAL_CHAR_FOUND;
                            }
                        } else {
                            /* no more input */
                            *err = U_ZERO_ERROR;
                        }
                    } else {
                        /* this is an unmatched trail code unit (2nd surrogate) */
                        /* callback(illegal) */
                        *err=U_ILLEGAL_CHAR_FOUND;
                    }
                } else {
                    /* callback(unassigned) for a BMP code point */
                    *err = U_INVALID_CHAR_FOUND;
                }

                args->converter->fromUChar32=mySourceChar;
                break;
            }
        }
        else{
            *err = U_BUFFER_OVERFLOW_ERROR;
            break;
        }
        targetUniChar=missingCharMarker;
    }

    args->target += myTargetIndex;
    args->source += mySourceIndex;
    myConverterData->isTargetUCharDBCS = isTargetUCharDBCS;
}

static void
_HZ_WriteSub(UConverterFromUnicodeArgs *args, int32_t offsetIndex, UErrorCode *err) {
    UConverter *cnv = args->converter;
    UConverterDataHZ *convData=(UConverterDataHZ *) cnv->extraInfo;
    char *p;
    char buffer[4];
    p = buffer;
    
    if( convData->isTargetUCharDBCS){
        *p++= UCNV_TILDE;
        *p++= UCNV_CLOSE_BRACE;
        convData->isTargetUCharDBCS=FALSE;
    }
    *p++= (char)cnv->subChars[0];

    ucnv_cbFromUWriteBytes(args,
                           buffer, (int32_t)(p - buffer),
                           offsetIndex, err);
}

/*
 * Structure for cloning an HZ converter into a single memory block.
 * ucnv_safeClone() of the HZ converter will align the entire cloneHZStruct,
 * and then ucnv_safeClone() of the sub-converter may additionally align
 * subCnv inside the cloneHZStruct, for which we need the deadSpace after
 * subCnv. This is because UAlignedMemory may be larger than the actually
 * necessary alignment size for the platform.
 * The other cloneHZStruct fields will not be moved around,
 * and are aligned properly with cloneHZStruct's alignment.
 */
struct cloneHZStruct
{
    UConverter cnv;
    UConverter subCnv;
    UAlignedMemory deadSpace;
    UConverterDataHZ mydata;
};


static UConverter * 
_HZ_SafeClone(const UConverter *cnv, 
              void *stackBuffer, 
              int32_t *pBufferSize, 
              UErrorCode *status)
{
    struct cloneHZStruct * localClone;
    int32_t size, bufferSizeNeeded = sizeof(struct cloneHZStruct);

    if (U_FAILURE(*status)){
        return 0;
    }

    if (*pBufferSize == 0){ /* 'preflighting' request - set needed size into *pBufferSize */
        *pBufferSize = bufferSizeNeeded;
        return 0;
    }

    localClone = (struct cloneHZStruct *)stackBuffer;
    /* ucnv.c/ucnv_safeClone() copied the main UConverter already */

    uprv_memcpy(&localClone->mydata, cnv->extraInfo, sizeof(UConverterDataHZ));
    localClone->cnv.extraInfo = &localClone->mydata;
    localClone->cnv.isExtraLocal = TRUE;

    /* deep-clone the sub-converter */
    size = (int32_t)(sizeof(UConverter) + sizeof(UAlignedMemory)); /* include size of padding */
    ((UConverterDataHZ*)localClone->cnv.extraInfo)->gbConverter =
        ucnv_safeClone(((UConverterDataHZ*)cnv->extraInfo)->gbConverter, &localClone->subCnv, &size, status);

    return &localClone->cnv;
}

static void
_HZ_GetUnicodeSet(const UConverter *cnv,
                  const USetAdder *sa,
                  UConverterUnicodeSet which,
                  UErrorCode *pErrorCode) {
    /* HZ converts all of ASCII */
    sa->addRange(sa->set, 0, 0x7f);

    /* add all of the code points that the sub-converter handles */
    ucnv_MBCSGetFilteredUnicodeSetForUnicode(
        ((UConverterDataHZ*)cnv->extraInfo)->gbConverter->sharedData,
        sa, which, UCNV_SET_FILTER_HZ,
        pErrorCode);
}

static const UConverterImpl _HZImpl={

    UCNV_HZ,
    
    NULL,
    NULL,
    
    _HZOpen,
    _HZClose,
    _HZReset,
    
    UConverter_toUnicode_HZ_OFFSETS_LOGIC,
    UConverter_toUnicode_HZ_OFFSETS_LOGIC,
    UConverter_fromUnicode_HZ_OFFSETS_LOGIC,
    UConverter_fromUnicode_HZ_OFFSETS_LOGIC,
    NULL,
    
    NULL,
    NULL,
    _HZ_WriteSub,
    _HZ_SafeClone,
    _HZ_GetUnicodeSet
};

static const UConverterStaticData _HZStaticData={
    sizeof(UConverterStaticData),
        "HZ",
         0, 
         UCNV_IBM, 
         UCNV_HZ, 
         1, 
         4,
        { 0x1a, 0, 0, 0 },
        1,
        FALSE, 
        FALSE,
        0,
        0,
        { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 }, /* reserved */

};

const UConverterSharedData _HZData=
        UCNV_IMMUTABLE_SHARED_DATA_INITIALIZER(&_HZStaticData, &_HZImpl);

#endif /* #if !UCONFIG_NO_CONVERSION && !UCONFIG_NO_LEGACY_CONVERSION && !UCONFIG_ONLY_HTML_CONVERSION */