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      1 // Copyright (C) 2016 and later: Unicode, Inc. and others.
      2 // License & terms of use: http://www.unicode.org/copyright.html
      3 /*
      4 **********************************************************************
      5 *   Copyright (C) 1999-2011, International Business Machines
      6 *   Corporation and others.  All Rights Reserved.
      7 **********************************************************************
      8 *
      9 *   ucnv_cnv.h:
     10 *   Definitions for converter implementations.
     11 *
     12 * Modification History:
     13 *
     14 *   Date        Name        Description
     15 *   05/09/00    helena      Added implementation to handle fallback mappings.
     16 *   06/29/2000  helena      Major rewrite of the callback APIs.
     17 */
     18 
     19 #ifndef UCNV_CNV_H
     20 #define UCNV_CNV_H
     21 
     22 #include "unicode/utypes.h"
     23 
     24 #if !UCONFIG_NO_CONVERSION
     25 
     26 #include "unicode/ucnv.h"
     27 #include "unicode/ucnv_err.h"
     28 #include "unicode/uset.h"
     29 #include "uset_imp.h"
     30 
     31 U_CDECL_BEGIN
     32 
     33 /* this is used in fromUnicode DBCS tables as an "unassigned" marker */
     34 #define missingCharMarker 0xFFFF
     35 
     36 /*
     37  * #define missingUCharMarker 0xfffe
     38  *
     39  * commented out because there are actually two values used in toUnicode tables:
     40  * U+fffe "unassigned"
     41  * U+ffff "illegal"
     42  */
     43 
     44 /** Forward declaration, see ucnv_bld.h */
     45 struct UConverterSharedData;
     46 typedef struct UConverterSharedData UConverterSharedData;
     47 
     48 /* function types for UConverterImpl ---------------------------------------- */
     49 
     50 /* struct with arguments for UConverterLoad and ucnv_load() */
     51 typedef struct {
     52     int32_t size;               /* sizeof(UConverterLoadArgs) */
     53     int32_t nestedLoads;        /* count nested ucnv_load() calls */
     54     UBool onlyTestIsLoadable;   /* input: don't actually load */
     55     UBool reserved0;            /* reserved - for good alignment of the pointers */
     56     int16_t reserved;           /* reserved - for good alignment of the pointers */
     57     uint32_t options;
     58     const char *pkg, *name, *locale;
     59 } UConverterLoadArgs;
     60 
     61 #define UCNV_LOAD_ARGS_INITIALIZER \
     62     { (int32_t)sizeof(UConverterLoadArgs), 0, FALSE, FALSE, 0, 0, NULL, NULL, NULL }
     63 
     64 typedef void (*UConverterLoad) (UConverterSharedData *sharedData,
     65                                 UConverterLoadArgs *pArgs,
     66                                 const uint8_t *raw, UErrorCode *pErrorCode);
     67 typedef void (*UConverterUnload) (UConverterSharedData *sharedData);
     68 
     69 typedef void (*UConverterOpen) (UConverter *cnv, UConverterLoadArgs *pArgs, UErrorCode *pErrorCode);
     70 typedef void (*UConverterClose) (UConverter *cnv);
     71 
     72 typedef enum UConverterResetChoice {
     73     UCNV_RESET_BOTH,
     74     UCNV_RESET_TO_UNICODE,
     75     UCNV_RESET_FROM_UNICODE
     76 } UConverterResetChoice;
     77 
     78 typedef void (*UConverterReset) (UConverter *cnv, UConverterResetChoice choice);
     79 
     80 /*
     81  * Converter implementation function(s) for ucnv_toUnicode().
     82  * If the toUnicodeWithOffsets function pointer is NULL,
     83  * then the toUnicode function will be used and the offsets will be set to -1.
     84  *
     85  * Must maintain state across buffers. Use toUBytes[toULength] for partial input
     86  * sequences; it will be checked in ucnv.c at the end of the input stream
     87  * to detect truncated input.
     88  * Some converters may need additional detection and may then set U_TRUNCATED_CHAR_FOUND.
     89  *
     90  * The toUnicodeWithOffsets must write exactly as many offset values as target
     91  * units. Write offset values of -1 for when the source index corresponding to
     92  * the output unit is not known (e.g., the character started in an earlier buffer).
     93  * The pArgs->offsets pointer need not be moved forward.
     94  *
     95  * At function return, either one of the following conditions must be true:
     96  * - U_BUFFER_OVERFLOW_ERROR and the target is full: target==targetLimit
     97  * - another error code with toUBytes[toULength] set to the offending input
     98  * - no error, and the source is consumed: source==sourceLimit
     99  *
    100  * The ucnv.c code will handle the end of the input (reset)
    101  * (reset, and truncation detection) and callbacks.
    102  */
    103 typedef void (*UConverterToUnicode) (UConverterToUnicodeArgs *, UErrorCode *);
    104 
    105 /*
    106  * Same rules as for UConverterToUnicode.
    107  * A lead surrogate is kept in fromUChar32 across buffers, and if an error
    108  * occurs, then the offending input code point must be put into fromUChar32
    109  * as well.
    110  */
    111 typedef void (*UConverterFromUnicode) (UConverterFromUnicodeArgs *, UErrorCode *);
    112 
    113 /*
    114  * Converter implementation function for ucnv_convertEx(), for direct conversion
    115  * between two charsets without pivoting through UTF-16.
    116  * The rules are the same as for UConverterToUnicode and UConverterFromUnicode.
    117  * In addition,
    118  * - The toUnicode side must behave and keep state exactly like the
    119  *   UConverterToUnicode implementation for the same source charset.
    120  * - A U_USING_DEFAULT_WARNING can be set to request to temporarily fall back
    121  *   to pivoting. When this function is called, the conversion framework makes
    122  *   sure that this warning is not set on input.
    123  * - Continuing a partial match and flushing the toUnicode replay buffer
    124  *   are handled by pivoting, using the toUnicode and fromUnicode functions.
    125  */
    126 typedef void (*UConverterConvert) (UConverterFromUnicodeArgs *pFromUArgs,
    127                                    UConverterToUnicodeArgs *pToUArgs,
    128                                    UErrorCode *pErrorCode);
    129 
    130 /*
    131  * Converter implementation function for ucnv_getNextUChar().
    132  * If the function pointer is NULL, then the toUnicode function will be used.
    133  *
    134  * Will be called at a character boundary (toULength==0).
    135  * May return with
    136  * - U_INDEX_OUTOFBOUNDS_ERROR if there was no output for the input
    137  *   (the return value will be ignored)
    138  * - U_TRUNCATED_CHAR_FOUND or another error code (never U_BUFFER_OVERFLOW_ERROR!)
    139  *   with toUBytes[toULength] set to the offending input
    140  *   (the return value will be ignored)
    141  * - return UCNV_GET_NEXT_UCHAR_USE_TO_U, without moving the source pointer,
    142  *   to indicate that the ucnv.c code shall call the toUnicode function instead
    143  * - return a real code point result
    144  *
    145  * Unless UCNV_GET_NEXT_UCHAR_USE_TO_U is returned, the source bytes must be consumed.
    146  *
    147  * The ucnv.c code will handle the end of the input (reset)
    148  * (except for truncation detection!) and callbacks.
    149  */
    150 typedef UChar32 (*UConverterGetNextUChar) (UConverterToUnicodeArgs *, UErrorCode *);
    151 
    152 typedef void (*UConverterGetStarters)(const UConverter* converter,
    153                                       UBool starters[256],
    154                                       UErrorCode *pErrorCode);
    155 
    156 /* If this function pointer is null or if the function returns null
    157  * the name field in static data struct should be returned by
    158  * ucnv_getName() API function
    159  */
    160 typedef const char * (*UConverterGetName) (const UConverter *cnv);
    161 
    162 /**
    163  * Write the codepage substitution character.
    164  * If this function is not set, then ucnv_cbFromUWriteSub() writes
    165  * the substitution character from UConverter.
    166  * For stateful converters, it is typically necessary to handle this
    167  * specificially for the converter in order to properly maintain the state.
    168  */
    169 typedef void (*UConverterWriteSub) (UConverterFromUnicodeArgs *pArgs, int32_t offsetIndex, UErrorCode *pErrorCode);
    170 
    171 /**
    172  * For converter-specific safeClone processing
    173  * If this function is not set, then ucnv_safeClone assumes that the converter has no private data that changes
    174  * after the converter is done opening.
    175  * If this function is set, then it is called just after a memcpy() of
    176  * converter data to the new, empty converter, and is expected to set up
    177  * the initial state of the converter.  It is not expected to increment the
    178  * reference counts of the standard data types such as the shared data.
    179  */
    180 typedef UConverter * (*UConverterSafeClone) (const UConverter   *cnv,
    181                                              void               *stackBuffer,
    182                                              int32_t            *pBufferSize,
    183                                              UErrorCode         *status);
    184 
    185 /**
    186  * Filters for some ucnv_getUnicodeSet() implementation code.
    187  */
    188 typedef enum UConverterSetFilter {
    189     UCNV_SET_FILTER_NONE,
    190     UCNV_SET_FILTER_DBCS_ONLY,
    191     UCNV_SET_FILTER_2022_CN,
    192     UCNV_SET_FILTER_SJIS,
    193     UCNV_SET_FILTER_GR94DBCS,
    194     UCNV_SET_FILTER_HZ,
    195     UCNV_SET_FILTER_COUNT
    196 } UConverterSetFilter;
    197 
    198 /**
    199  * Fills the set of Unicode code points that can be converted by an ICU converter.
    200  * The API function ucnv_getUnicodeSet() clears the USet before calling
    201  * the converter's getUnicodeSet() implementation; the converter should only
    202  * add the appropriate code points to allow recursive use.
    203  * For example, the ISO-2022-JP converter will call each subconverter's
    204  * getUnicodeSet() implementation to consecutively add code points to
    205  * the same USet, which will result in a union of the sets of all subconverters.
    206  *
    207  * For more documentation, see ucnv_getUnicodeSet() in ucnv.h.
    208  */
    209 typedef void (*UConverterGetUnicodeSet) (const UConverter *cnv,
    210                                          const USetAdder *sa,
    211                                          UConverterUnicodeSet which,
    212                                          UErrorCode *pErrorCode);
    213 
    214 UBool CONVERSION_U_SUCCESS (UErrorCode err);
    215 
    216 /**
    217  * UConverterImpl contains all the data and functions for a converter type.
    218  * Its function pointers work much like a C++ vtable.
    219  * Many converter types need to define only a subset of the functions;
    220  * when a function pointer is NULL, then a default action will be performed.
    221  *
    222  * Every converter type must implement toUnicode, fromUnicode, and getNextUChar,
    223  * otherwise the converter may crash.
    224  * Every converter type that has variable-length codepage sequences should
    225  * also implement toUnicodeWithOffsets and fromUnicodeWithOffsets for
    226  * correct offset handling.
    227  * All other functions may or may not be implemented - it depends only on
    228  * whether the converter type needs them.
    229  *
    230  * When open() fails, then close() will be called, if present.
    231  */
    232 struct UConverterImpl {
    233     UConverterType type;
    234 
    235     UConverterLoad load;
    236     UConverterUnload unload;
    237 
    238     UConverterOpen open;
    239     UConverterClose close;
    240     UConverterReset reset;
    241 
    242     UConverterToUnicode toUnicode;
    243     UConverterToUnicode toUnicodeWithOffsets;
    244     UConverterFromUnicode fromUnicode;
    245     UConverterFromUnicode fromUnicodeWithOffsets;
    246     UConverterGetNextUChar getNextUChar;
    247 
    248     UConverterGetStarters getStarters;
    249     UConverterGetName getName;
    250     UConverterWriteSub writeSub;
    251     UConverterSafeClone safeClone;
    252     UConverterGetUnicodeSet getUnicodeSet;
    253 
    254     UConverterConvert toUTF8;
    255     UConverterConvert fromUTF8;
    256 };
    257 
    258 extern const UConverterSharedData
    259     _MBCSData, _Latin1Data,
    260     _UTF8Data, _UTF16BEData, _UTF16LEData, _UTF32BEData, _UTF32LEData,
    261     _ISO2022Data,
    262     _LMBCSData1,_LMBCSData2, _LMBCSData3, _LMBCSData4, _LMBCSData5, _LMBCSData6,
    263     _LMBCSData8,_LMBCSData11,_LMBCSData16,_LMBCSData17,_LMBCSData18,_LMBCSData19,
    264     _HZData,_ISCIIData, _SCSUData, _ASCIIData,
    265     _UTF7Data, _Bocu1Data, _UTF16Data, _UTF32Data, _CESU8Data, _IMAPData, _CompoundTextData;
    266 
    267 U_CDECL_END
    268 
    269 /** Always use fallbacks from codepage to Unicode */
    270 #define TO_U_USE_FALLBACK(useFallback) TRUE
    271 #define UCNV_TO_U_USE_FALLBACK(cnv) TRUE
    272 
    273 /** Use fallbacks from Unicode to codepage when cnv->useFallback or for private-use code points */
    274 #define IS_PRIVATE_USE(c) ((uint32_t)((c)-0xe000)<0x1900 || (uint32_t)((c)-0xf0000)<0x20000)
    275 #define FROM_U_USE_FALLBACK(useFallback, c) ((useFallback) || IS_PRIVATE_USE(c))
    276 #define UCNV_FROM_U_USE_FALLBACK(cnv, c) FROM_U_USE_FALLBACK((cnv)->useFallback, c)
    277 
    278 /**
    279  * Magic number for ucnv_getNextUChar(), returned by a
    280  * getNextUChar() implementation to indicate to use the converter's toUnicode()
    281  * instead of the native function.
    282  * @internal
    283  */
    284 #define UCNV_GET_NEXT_UCHAR_USE_TO_U -9
    285 
    286 U_CFUNC void
    287 ucnv_getCompleteUnicodeSet(const UConverter *cnv,
    288                    const USetAdder *sa,
    289                    UConverterUnicodeSet which,
    290                    UErrorCode *pErrorCode);
    291 
    292 U_CFUNC void
    293 ucnv_getNonSurrogateUnicodeSet(const UConverter *cnv,
    294                                const USetAdder *sa,
    295                                UConverterUnicodeSet which,
    296                                UErrorCode *pErrorCode);
    297 
    298 U_CFUNC void
    299 ucnv_fromUWriteBytes(UConverter *cnv,
    300                      const char *bytes, int32_t length,
    301                      char **target, const char *targetLimit,
    302                      int32_t **offsets,
    303                      int32_t sourceIndex,
    304                      UErrorCode *pErrorCode);
    305 U_CFUNC void
    306 ucnv_toUWriteUChars(UConverter *cnv,
    307                     const UChar *uchars, int32_t length,
    308                     UChar **target, const UChar *targetLimit,
    309                     int32_t **offsets,
    310                     int32_t sourceIndex,
    311                     UErrorCode *pErrorCode);
    312 
    313 U_CFUNC void
    314 ucnv_toUWriteCodePoint(UConverter *cnv,
    315                        UChar32 c,
    316                        UChar **target, const UChar *targetLimit,
    317                        int32_t **offsets,
    318                        int32_t sourceIndex,
    319                        UErrorCode *pErrorCode);
    320 
    321 #endif
    322 
    323 #endif /* UCNV_CNV */
    324