1// Copyright (C) 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/*
4******************************************************************************
5*
6*   Copyright (C) 2000-2013, International Business Machines
7*   Corporation and others.  All Rights Reserved.
8*
9******************************************************************************
10*   file name:  ucnvmbcs.h
11*   encoding:   US-ASCII
12*   tab size:   8 (not used)
13*   indentation:4
14*
15*   created on: 2000jul07
16*   created by: Markus W. Scherer
17*/
18
19#ifndef __UCNVMBCS_H__
20#define __UCNVMBCS_H__
21
22#include "unicode/utypes.h"
23
24#if !UCONFIG_NO_CONVERSION
25
26#include "unicode/ucnv.h"
27#include "ucnv_cnv.h"
28#include "ucnv_ext.h"
29
30/**
31 * ICU conversion (.cnv) data file structure, following the usual UDataInfo
32 * header.
33 *
34 * Format version: 6.2
35 *
36 * struct UConverterStaticData -- struct containing the converter name, IBM CCSID,
37 *                                min/max bytes per character, etc.
38 *                                see ucnv_bld.h
39 *
40 * --------------------
41 *
42 * The static data is followed by conversionType-specific data structures.
43 * At the moment, there are only variations of MBCS converters. They all have
44 * the same toUnicode structures, while the fromUnicode structures for SBCS
45 * differ from those for other MBCS-style converters.
46 *
47 * _MBCSHeader.version 5 is optional and not backward-compatible
48 * (as usual for changes in the major version field).
49 *
50 * Versions 5.m work like versions 4.m except:
51 * - The _MBCSHeader has variable length (and is always longer than in version 4).
52 *   See the struct _MBCSHeader further description below.
53 * - There is a set of flags which indicate further incompatible changes.
54 *   (Reader code must reject the file if it does not recognize them all.)
55 * - In particular, one of these flags indicates that most of the fromUnicode
56 *   data is missing and must be reconstituted from the toUnicode data
57 *   and from the utf8Friendly mbcsIndex at load time.
58 *   (This only works with a utf8Friendly table.)
59 *   In this case, makeconv may increase maxFastUChar automatically to U+FFFF.
60 *
61 * The first of these versions is 5.3, which is like 4.3 except for the differences above.
62 *
63 * When possible, makeconv continues to generate version 4.m files.
64 *
65 * _MBCSHeader.version 5.4/4.4 supports "good one-way" mappings (|4)
66 * in the extension tables (fromUTableValues bit 30). See ucnv_ext.h for details.
67 *
68 * _MBCSHeader.version 4.3 optionally modifies the fromUnicode data structures
69 * slightly and optionally adds a table for conversion to MBCS (non-SBCS)
70 * charsets.
71 *
72 * The modifications are to make the data utf8Friendly. Not every 4.3 file
73 * file contains utf8Friendly data.
74 * It is utf8Friendly if _MBCSHeader.version[2]!=0.
75 * In this case, the data structures are utf8Friendly up to the code point
76 *   maxFastUChar=((_MBCSHeader.version[2]<<8)|0xff)
77 *
78 * A utf8Friendly file has fromUnicode stage 3 entries for code points up to
79 * maxFastUChar allocated in blocks of 64 for indexing with the 6 bits from
80 * a UTF-8 trail byte. ASCII is allocated linearly with 128 contiguous entries.
81 *
82 * In addition, a utf8Friendly MBCS file contains an additional
83 *   uint16_t mbcsIndex[(maxFastUChar+1)>>6];
84 * which replaces the stage 1 and 2 tables for indexing with bits from the
85 * UTF-8 lead byte and middle trail byte. Unlike the older MBCS stage 2 table,
86 * the mbcsIndex does not contain roundtrip flags. Therefore, all fallbacks
87 * from code points up to maxFastUChar (and roundtrips to 0x00) are moved to
88 * the extension data structure. This also allows for faster roundtrip
89 * conversion from UTF-16.
90 *
91 * SBCS files do not contain an additional sbcsIndex[] array because the
92 * proportional size increase would be noticeable, but the runtime
93 * code builds one for the code point range for which the runtime conversion
94 * code is optimized.
95 *
96 * For SBCS, maxFastUChar should be at least U+0FFF. The initial makeconv
97 * implementation sets it to U+1FFF. Because the sbcsIndex is not stored in
98 * the file, a larger maxFastUChar only affects stage 3 block allocation size
99 * and is free in empty blocks. (Larger blocks with sparse contents cause larger
100 * files.) U+1FFF includes almost all of the small scripts.
101 * U+0FFF covers UTF-8 two-byte sequences and three-byte sequences starting with
102 * 0xe0. This includes most scripts with legacy SBCS charsets.
103 * The initial runtime implementation using 4.3 files only builds an sbcsIndex
104 * for code points up to U+0FFF.
105 *
106 * For MBCS, maxFastUChar should be at least U+D7FF (=initial value).
107 * This boundary is convenient because practically all of the commonly used
108 * characters are below it, and because it is the boundary to surrogate
109 * code points, above which special handling is necessary anyway.
110 * (Surrogate pair assembly for UTF-16, validity checking for UTF-8.)
111 *
112 * maxFastUChar could be up to U+FFFF to cover the whole BMP, which could be
113 * useful especially for conversion from UTF-8 when the input can be assumed
114 * to be valid, because the surrogate range would then not have to be
115 * checked.
116 * (With maxFastUChar=0xffff, makeconv would have to check for mbcsIndex value
117 * overflow because with the all-unassigned block 0 and nearly full mappings
118 * from the BMP it is theoretically possible that an index into stage 3
119 * exceeds 16 bits.)
120 *
121 * _MBCSHeader.version 4.2 adds an optional conversion extension data structure.
122 * If it is present, then an ICU version reading header versions 4.0 or 4.1
123 * will be able to use the base table and ignore the extension.
124 *
125 * The unicodeMask in the static data is part of the base table data structure.
126 * Especially, the UCNV_HAS_SUPPLEMENTARY flag determines the length of the
127 * fromUnicode stage 1 array.
128 * The static data unicodeMask refers only to the base table's properties if
129 * a base table is included.
130 * In an extension-only file, the static data unicodeMask is 0.
131 * The extension data indexes have a separate field with the unicodeMask flags.
132 *
133 * MBCS-style data structure following the static data.
134 * Offsets are counted in bytes from the beginning of the MBCS header structure.
135 * Details about usage in comments in ucnvmbcs.c.
136 *
137 * struct _MBCSHeader (see the definition in this header file below)
138 * contains 32-bit fields as follows:
139 * 8 values:
140 *  0   uint8_t[4]  MBCS version in UVersionInfo format (currently 4.3.x.0)
141 *  1   uint32_t    countStates
142 *  2   uint32_t    countToUFallbacks
143 *  3   uint32_t    offsetToUCodeUnits
144 *  4   uint32_t    offsetFromUTable
145 *  5   uint32_t    offsetFromUBytes
146 *  6   uint32_t    flags, bits:
147 *                      31.. 8 offsetExtension -- _MBCSHeader.version 4.2 (ICU 2.8) and higher
148 *                                                0 for older versions and if
149 *                                                there is not extension structure
150 *                       7.. 0 outputType
151 *  7   uint32_t    fromUBytesLength -- _MBCSHeader.version 4.1 (ICU 2.4) and higher
152 *                  counts bytes in fromUBytes[]
153 *
154 * New and required in version 5:
155 *  8   uint32_t    options, bits:
156 *                      31..16 reserved for flags that can be added without breaking
157 *                                 backward compatibility
158 *                      15.. 6 reserved for flags whose addition will break
159 *                                 backward compatibility
160 *                           6 MBCS_OPT_FROM_U -- if set,
161 *                                 then most of the fromUnicode data is omitted;
162 *                                 fullStage2Length is present and the missing
163 *                                 bottom part of stage 2 must be reconstituted from
164 *                                 the toUnicode data;
165 *                                 stage 3 is missing completely as well;
166 *                                 not used for SBCS tables
167 *                       5.. 0 length of the _MBCSHeader (number of uint32_t)
168 *
169 * New and optional in version 5:
170 *  9   uint32_t    fullStage2Length: used if MBCS_OPT_FROM_U is set
171 *                                 specifies the full length of stage 2
172 *                                 including the omitted part
173 *
174 * if(outputType==MBCS_OUTPUT_EXT_ONLY) {
175 *     -- base table name for extension-only table
176 *     char baseTableName[variable]; -- with NUL plus padding for 4-alignment
177 *
178 *     -- all _MBCSHeader fields except for version and flags are 0
179 * } else {
180 *     -- normal base table with optional extension
181 *
182 *     int32_t stateTable[countStates][256];
183 *
184 *     struct _MBCSToUFallback { (fallbacks are sorted by offset)
185 *         uint32_t offset;
186 *         UChar32 codePoint;
187 *     } toUFallbacks[countToUFallbacks];
188 *
189 *     uint16_t unicodeCodeUnits[(offsetFromUTable-offsetToUCodeUnits)/2];
190 *                  (padded to an even number of units)
191 *
192 *     -- stage 1 tables
193 *     if(staticData.unicodeMask&UCNV_HAS_SUPPLEMENTARY) {
194 *         -- stage 1 table for all of Unicode
195 *         uint16_t fromUTable[0x440]; (32-bit-aligned)
196 *     } else {
197 *         -- BMP-only tables have a smaller stage 1 table
198 *         uint16_t fromUTable[0x40]; (32-bit-aligned)
199 *     }
200 *
201 *     -- stage 2 tables
202 *        length determined by top of stage 1 and bottom of stage 3 tables
203 *     if(outputType==MBCS_OUTPUT_1) {
204 *         -- SBCS: pure indexes
205 *         uint16_t stage 2 indexes[?];
206 *     } else {
207 *         -- DBCS, MBCS, EBCDIC_STATEFUL, ...: roundtrip flags and indexes
208 *         uint32_t stage 2 flags and indexes[?];
209 *         if(options&MBCS_OPT_NO_FROM_U) {
210 *             stage 2 really has length fullStage2Length
211 *             and the omitted lower part must be reconstituted from
212 *             the toUnicode data
213 *         }
214 *     }
215 *
216 *     -- stage 3 tables with byte results
217 *     if(outputType==MBCS_OUTPUT_1) {
218 *         -- SBCS: each 16-bit result contains flags and the result byte, see ucnvmbcs.c
219 *         uint16_t fromUBytes[fromUBytesLength/2];
220 *     } else if(!(options&MBCS_OPT_NO_FROM_U)) {
221 *         -- DBCS, MBCS, EBCDIC_STATEFUL, ... 2/3/4 bytes result, see ucnvmbcs.c
222 *         uint8_t fromUBytes[fromUBytesLength]; or
223 *         uint16_t fromUBytes[fromUBytesLength/2]; or
224 *         uint32_t fromUBytes[fromUBytesLength/4];
225 *     } else {
226 *         fromUBytes[] must be reconstituted from the toUnicode data
227 *     }
228 *
229 *     -- optional utf8Friendly mbcsIndex -- _MBCSHeader.version 4.3 (ICU 3.8) and higher
230 *     if(outputType!=MBCS_OUTPUT_1 &&
231 *        _MBCSHeader.version[1]>=3 &&
232 *        (maxFastUChar=_MBCSHeader.version[2])!=0
233 *     ) {
234 *         maxFastUChar=(maxFastUChar<<8)|0xff;
235 *         uint16_t mbcsIndex[(maxFastUChar+1)>>6];
236 *     }
237 * }
238 *
239 * -- extension table, details see ucnv_ext.h
240 * int32_t indexes[>=32]; ...
241 */
242
243/* MBCS converter data and state -------------------------------------------- */
244
245enum {
246    MBCS_MAX_STATE_COUNT=128
247};
248
249/**
250 * MBCS action codes for conversions to Unicode.
251 * These values are in bits 23..20 of the state table entries.
252 */
253enum {
254    MBCS_STATE_VALID_DIRECT_16,
255    MBCS_STATE_VALID_DIRECT_20,
256
257    MBCS_STATE_FALLBACK_DIRECT_16,
258    MBCS_STATE_FALLBACK_DIRECT_20,
259
260    MBCS_STATE_VALID_16,
261    MBCS_STATE_VALID_16_PAIR,
262
263    MBCS_STATE_UNASSIGNED,
264    MBCS_STATE_ILLEGAL,
265
266    MBCS_STATE_CHANGE_ONLY
267};
268
269/* Macros for state table entries */
270#define MBCS_ENTRY_TRANSITION(state, offset) (int32_t)(((int32_t)(state)<<24L)|(offset))
271#define MBCS_ENTRY_TRANSITION_SET_OFFSET(entry, offset) (int32_t)(((entry)&0xff000000)|(offset))
272#define MBCS_ENTRY_TRANSITION_ADD_OFFSET(entry, offset) (int32_t)((entry)+(offset))
273
274#define MBCS_ENTRY_FINAL(state, action, value) (int32_t)(0x80000000|((int32_t)(state)<<24L)|((action)<<20L)|(value))
275#define MBCS_ENTRY_SET_FINAL(entry) (int32_t)((entry)|0x80000000)
276#define MBCS_ENTRY_FINAL_SET_ACTION(entry, action) (int32_t)(((entry)&0xff0fffff)|((int32_t)(action)<<20L))
277#define MBCS_ENTRY_FINAL_SET_VALUE(entry, value) (int32_t)(((entry)&0xfff00000)|(value))
278#define MBCS_ENTRY_FINAL_SET_ACTION_VALUE(entry, action, value) (int32_t)(((entry)&0xff000000)|((int32_t)(action)<<20L)|(value))
279
280#define MBCS_ENTRY_SET_STATE(entry, state) (int32_t)(((entry)&0x80ffffff)|((int32_t)(state)<<24L))
281
282#define MBCS_ENTRY_STATE(entry) ((((uint32_t)entry)>>24)&0x7f)
283
284#define MBCS_ENTRY_IS_TRANSITION(entry) ((entry)>=0)
285#define MBCS_ENTRY_IS_FINAL(entry) ((entry)<0)
286
287#define MBCS_ENTRY_TRANSITION_STATE(entry) (((uint32_t)entry)>>24)
288#define MBCS_ENTRY_TRANSITION_OFFSET(entry) ((entry)&0xffffff)
289
290#define MBCS_ENTRY_FINAL_STATE(entry) ((((uint32_t)entry)>>24)&0x7f)
291#define MBCS_ENTRY_FINAL_IS_VALID_DIRECT_16(entry) ((entry)<(int32_t)0x80100000)
292#define MBCS_ENTRY_FINAL_ACTION(entry) ((((uint32_t)entry)>>20)&0xf)
293#define MBCS_ENTRY_FINAL_VALUE(entry) ((entry)&0xfffff)
294#define MBCS_ENTRY_FINAL_VALUE_16(entry) (uint16_t)(entry)
295
296#define IS_ASCII_ROUNDTRIP(b, asciiRoundtrips) (((asciiRoundtrips) & (1<<((b)>>2)))!=0)
297
298/* single-byte fromUnicode: get the 16-bit result word */
299#define MBCS_SINGLE_RESULT_FROM_U(table, results, c) (results)[ (table)[ (table)[(c)>>10] +(((c)>>4)&0x3f) ] +((c)&0xf) ]
300
301/* single-byte fromUnicode using the sbcsIndex */
302#define SBCS_RESULT_FROM_LOW_BMP(table, results, c) (results)[ (table)[(c)>>6] +((c)&0x3f) ]
303
304/* single-byte fromUTF8 using the sbcsIndex; l and t must be masked externally; can be l=0 and t<=0x7f */
305#define SBCS_RESULT_FROM_UTF8(table, results, l, t) (results)[ (table)[l] +(t) ]
306
307/* multi-byte fromUnicode: get the 32-bit stage 2 entry */
308#define MBCS_STAGE_2_FROM_U(table, c) ((const uint32_t *)(table))[ (table)[(c)>>10] +(((c)>>4)&0x3f) ]
309#define MBCS_FROM_U_IS_ROUNDTRIP(stage2Entry, c) ( ((stage2Entry) & ((uint32_t)1<< (16+((c)&0xf)) )) !=0)
310
311#define MBCS_VALUE_2_FROM_STAGE_2(bytes, stage2Entry, c) ((uint16_t *)(bytes))[16*(uint32_t)(uint16_t)(stage2Entry)+((c)&0xf)]
312#define MBCS_VALUE_4_FROM_STAGE_2(bytes, stage2Entry, c) ((uint32_t *)(bytes))[16*(uint32_t)(uint16_t)(stage2Entry)+((c)&0xf)]
313
314#define MBCS_POINTER_3_FROM_STAGE_2(bytes, stage2Entry, c) ((bytes)+(16*(uint32_t)(uint16_t)(stage2Entry)+((c)&0xf))*3)
315
316/* double-byte fromUnicode using the mbcsIndex */
317#define DBCS_RESULT_FROM_MOST_BMP(table, results, c) (results)[ (table)[(c)>>6] +((c)&0x3f) ]
318
319/* double-byte fromUTF8 using the mbcsIndex; l and t1 combined into lt1; lt1 and t2 must be masked externally */
320#define DBCS_RESULT_FROM_UTF8(table, results, lt1, t2) (results)[ (table)[lt1] +(t2) ]
321
322
323/**
324 * MBCS output types for conversions from Unicode.
325 * These per-converter types determine the storage method in stage 3 of the lookup table,
326 * mostly how many bytes are stored per entry.
327 */
328enum {
329    MBCS_OUTPUT_1,          /* 0 */
330    MBCS_OUTPUT_2,          /* 1 */
331    MBCS_OUTPUT_3,          /* 2 */
332    MBCS_OUTPUT_4,          /* 3 */
333
334    MBCS_OUTPUT_3_EUC=8,    /* 8 */
335    MBCS_OUTPUT_4_EUC,      /* 9 */
336
337    MBCS_OUTPUT_2_SISO=12,  /* c */
338    MBCS_OUTPUT_2_HZ,       /* d */
339
340    MBCS_OUTPUT_EXT_ONLY,   /* e */
341
342    MBCS_OUTPUT_COUNT,
343
344    MBCS_OUTPUT_DBCS_ONLY=0xdb  /* runtime-only type for DBCS-only handling of SISO tables */
345};
346
347/**
348 * Fallbacks to Unicode are stored outside the normal state table and code point structures
349 * in a vector of items of this type. They are sorted by offset.
350 */
351typedef struct {
352    uint32_t offset;
353    UChar32 codePoint;
354} _MBCSToUFallback;
355
356/** Constants for fast and UTF-8-friendly conversion. */
357enum {
358    SBCS_FAST_MAX=0x0fff,               /* maximum code point with UTF-8-friendly SBCS runtime code, see makeconv SBCS_UTF8_MAX */
359    SBCS_FAST_LIMIT=SBCS_FAST_MAX+1,    /* =0x1000 */
360    MBCS_FAST_MAX=0xd7ff,               /* maximum code point with UTF-8-friendly MBCS runtime code, see makeconv MBCS_UTF8_MAX */
361    MBCS_FAST_LIMIT=MBCS_FAST_MAX+1     /* =0xd800 */
362};
363
364/**
365 * This is the MBCS part of the UConverterTable union (a runtime data structure).
366 * It keeps all the per-converter data and points into the loaded mapping tables.
367 *
368 * utf8Friendly data structures added with _MBCSHeader.version 4.3
369 */
370typedef struct UConverterMBCSTable {
371    /* toUnicode */
372    uint8_t countStates, dbcsOnlyState, stateTableOwned;
373    uint32_t countToUFallbacks;
374
375    const int32_t (*stateTable)/*[countStates]*/[256];
376    int32_t (*swapLFNLStateTable)/*[countStates]*/[256]; /* for swaplfnl */
377    const uint16_t *unicodeCodeUnits/*[countUnicodeResults]*/;
378    const _MBCSToUFallback *toUFallbacks;
379
380    /* fromUnicode */
381    const uint16_t *fromUnicodeTable;
382    const uint16_t *mbcsIndex;              /* for fast conversion from most of BMP to MBCS (utf8Friendly data) */
383    uint16_t sbcsIndex[SBCS_FAST_LIMIT>>6]; /* for fast conversion from low BMP to SBCS (utf8Friendly data) */
384    const uint8_t *fromUnicodeBytes;
385    uint8_t *swapLFNLFromUnicodeBytes;      /* for swaplfnl */
386    uint32_t fromUBytesLength;
387    uint8_t outputType, unicodeMask;
388    UBool utf8Friendly;                     /* for utf8Friendly data */
389    UChar maxFastUChar;                     /* for utf8Friendly data */
390
391    /* roundtrips */
392    uint32_t asciiRoundtrips;
393
394    /* reconstituted data that was omitted from the .cnv file */
395    uint8_t *reconstitutedData;
396
397    /* converter name for swaplfnl */
398    char *swapLFNLName;
399
400    /* extension data */
401    struct UConverterSharedData *baseSharedData;
402    const int32_t *extIndexes;
403} UConverterMBCSTable;
404
405#define UCNV_MBCS_TABLE_INITIALIZER { \
406    /* toUnicode */ \
407    0, 0, 0, \
408    0, \
409     \
410    NULL, \
411    NULL, \
412    NULL, \
413    NULL, \
414     \
415    /* fromUnicode */ \
416    NULL, \
417    NULL, \
418    { 0 }, \
419    NULL, \
420    NULL, \
421    0, \
422    0, 0, \
423    FALSE, \
424    0, \
425     \
426    /* roundtrips */ \
427    0, \
428     \
429    /* reconstituted data that was omitted from the .cnv file */ \
430    NULL, \
431     \
432    /* converter name for swaplfnl */ \
433    NULL, \
434     \
435    /* extension data */ \
436    NULL, \
437    NULL \
438}
439
440enum {
441    MBCS_OPT_LENGTH_MASK=0x3f,
442    MBCS_OPT_NO_FROM_U=0x40,
443    /*
444     * If any of the following options bits are set,
445     * then the file must be rejected.
446     */
447    MBCS_OPT_INCOMPATIBLE_MASK=0xffc0,
448    /*
449     * Remove bits from this mask as more options are recognized
450     * by all implementations that use this constant.
451     */
452    MBCS_OPT_UNKNOWN_INCOMPATIBLE_MASK=0xff80
453};
454
455enum {
456    MBCS_HEADER_V4_LENGTH=8,
457    MBCS_HEADER_V5_MIN_LENGTH=9
458};
459
460/**
461 * MBCS data header. See data format description above.
462 */
463typedef struct {
464    UVersionInfo version;
465    uint32_t countStates,
466             countToUFallbacks,
467             offsetToUCodeUnits,
468             offsetFromUTable,
469             offsetFromUBytes,
470             flags,
471             fromUBytesLength;
472
473    /* new and required in version 5 */
474    uint32_t options;
475
476    /* new and optional in version 5; used if options&MBCS_OPT_NO_FROM_U */
477    uint32_t fullStage2Length;  /* number of 32-bit units */
478} _MBCSHeader;
479
480#define UCNV_MBCS_HEADER_INITIALIZER { { 0 },  0, 0, 0, 0, 0, 0, 0,  0,  0 }
481
482/*
483 * This is a simple version of _MBCSGetNextUChar() that is used
484 * by other converter implementations.
485 * It only returns an "assigned" result if it consumes the entire input.
486 * It does not use state from the converter, nor error codes.
487 * It does not handle the EBCDIC swaplfnl option (set in UConverter).
488 * It handles conversion extensions but not GB 18030.
489 *
490 * Return value:
491 * U+fffe   unassigned
492 * U+ffff   illegal
493 * otherwise the Unicode code point
494 */
495U_CFUNC UChar32
496ucnv_MBCSSimpleGetNextUChar(UConverterSharedData *sharedData,
497                        const char *source, int32_t length,
498                        UBool useFallback);
499
500/**
501 * This version of _MBCSSimpleGetNextUChar() is optimized for single-byte, single-state codepages.
502 * It does not handle the EBCDIC swaplfnl option (set in UConverter).
503 * It does not handle conversion extensions (_extToU()).
504 */
505U_CFUNC UChar32
506ucnv_MBCSSingleSimpleGetNextUChar(UConverterSharedData *sharedData,
507                              uint8_t b, UBool useFallback);
508
509/**
510 * This macro version of _MBCSSingleSimpleGetNextUChar() gets a code point from a byte.
511 * It works for single-byte, single-state codepages that only map
512 * to and from BMP code points, and it always
513 * returns fallback values.
514 */
515#define _MBCS_SINGLE_SIMPLE_GET_NEXT_BMP(sharedData, b) \
516    (UChar)MBCS_ENTRY_FINAL_VALUE_16((sharedData)->mbcs.stateTable[0][(uint8_t)(b)])
517
518/**
519 * This is an internal function that allows other converter implementations
520 * to check whether a byte is a lead byte.
521 */
522U_CFUNC UBool
523ucnv_MBCSIsLeadByte(UConverterSharedData *sharedData, char byte);
524
525/** This is a macro version of _MBCSIsLeadByte(). */
526#define _MBCS_IS_LEAD_BYTE(sharedData, byte) \
527    (UBool)MBCS_ENTRY_IS_TRANSITION((sharedData)->mbcs.stateTable[0][(uint8_t)(byte)])
528
529/*
530 * This is another simple conversion function for internal use by other
531 * conversion implementations.
532 * It does not use the converter state nor call callbacks.
533 * It does not handle the EBCDIC swaplfnl option (set in UConverter).
534 * It handles conversion extensions but not GB 18030.
535 *
536 * It converts one single Unicode code point into codepage bytes, encoded
537 * as one 32-bit value. The function returns the number of bytes in *pValue:
538 * 1..4 the number of bytes in *pValue
539 * 0    unassigned (*pValue undefined)
540 * -1   illegal (currently not used, *pValue undefined)
541 *
542 * *pValue will contain the resulting bytes with the last byte in bits 7..0,
543 * the second to last byte in bits 15..8, etc.
544 * Currently, the function assumes but does not check that 0<=c<=0x10ffff.
545 */
546U_CFUNC int32_t
547ucnv_MBCSFromUChar32(UConverterSharedData *sharedData,
548                 UChar32 c, uint32_t *pValue,
549                 UBool useFallback);
550
551/**
552 * This version of _MBCSFromUChar32() is optimized for single-byte codepages.
553 * It does not handle the EBCDIC swaplfnl option (set in UConverter).
554 *
555 * It returns the codepage byte for the code point, or -1 if it is unassigned.
556 */
557U_CFUNC int32_t
558ucnv_MBCSSingleFromUChar32(UConverterSharedData *sharedData,
559                       UChar32 c,
560                       UBool useFallback);
561
562/**
563 * SBCS, DBCS, and EBCDIC_STATEFUL are replaced by MBCS, but
564 * we cheat a little about the type, returning the old types if appropriate.
565 */
566U_CFUNC UConverterType
567ucnv_MBCSGetType(const UConverter* converter);
568
569U_CFUNC void
570ucnv_MBCSFromUnicodeWithOffsets(UConverterFromUnicodeArgs *pArgs,
571                            UErrorCode *pErrorCode);
572U_CFUNC void
573ucnv_MBCSToUnicodeWithOffsets(UConverterToUnicodeArgs *pArgs,
574                          UErrorCode *pErrorCode);
575
576/*
577 * Internal function returning a UnicodeSet for toUnicode() conversion.
578 * Currently only used for ISO-2022-CN, and only handles roundtrip mappings.
579 * In the future, if we add support for fallback sets, this function
580 * needs to be updated.
581 * Handles extensions.
582 * Does not empty the set first.
583 */
584U_CFUNC void
585ucnv_MBCSGetUnicodeSetForUnicode(const UConverterSharedData *sharedData,
586                                 const USetAdder *sa,
587                                 UConverterUnicodeSet which,
588                                 UErrorCode *pErrorCode);
589
590/*
591 * Same as ucnv_MBCSGetUnicodeSetForUnicode() but
592 * the set can be filtered by encoding scheme.
593 * Used by stateful converters which share regular conversion tables
594 * but only use a subset of their mappings.
595 */
596U_CFUNC void
597ucnv_MBCSGetFilteredUnicodeSetForUnicode(const UConverterSharedData *sharedData,
598                                         const USetAdder *sa,
599                                         UConverterUnicodeSet which,
600                                         UConverterSetFilter filter,
601                                         UErrorCode *pErrorCode);
602
603#endif
604
605#endif
606