Home | History | Annotate | Download | only in common 
      1 /*
      2 **********************************************************************
      3 *   Copyright (C) 1999-2010, International Business Machines
      4 *   Corporation and others.  All Rights Reserved.
      5 **********************************************************************
      6 *
      7 *   ucnv_cnv.h:
      8 *   Definitions for converter implementations.
      9 *
     10 * Modification History:
     11 *
     12 *   Date        Name        Description
     13 *   05/09/00    helena      Added implementation to handle fallback mappings.
     14 *   06/29/2000  helena      Major rewrite of the callback APIs.
     15 */
     16 
     17 #ifndef UCNV_CNV_H
     18 #define UCNV_CNV_H
     19 
     20 #include "unicode/utypes.h"
     21 
     22 #if !UCONFIG_NO_CONVERSION
     23 
     24 #include "unicode/ucnv.h"
     25 #include "unicode/ucnv_err.h"
     26 #include "unicode/uset.h"
     27 #include "uset_imp.h"
     28 
     29 U_CDECL_BEGIN
     30 
     31 /* this is used in fromUnicode DBCS tables as an "unassigned" marker */
     32 #define missingCharMarker 0xFFFF
     33 
     34 /*
     35  * #define missingUCharMarker 0xfffe
     36  *
     37  * commented out because there are actually two values used in toUnicode tables:
     38  * U+fffe "unassigned"
     39  * U+ffff "illegal"
     40  */
     41 
     42 /** Forward declaration, see ucnv_bld.h */
     43 struct UConverterSharedData;
     44 typedef struct UConverterSharedData UConverterSharedData;
     45 
     46 /* function types for UConverterImpl ---------------------------------------- */
     47 
     48 /* struct with arguments for UConverterLoad and ucnv_load() */
     49 typedef struct {
     50     int32_t size;               /* sizeof(UConverterLoadArgs) */
     51     int32_t nestedLoads;        /* count nested ucnv_load() calls */
     52     UBool onlyTestIsLoadable;   /* input: don't actually load */
     53     UBool reserved0;            /* reserved - for good alignment of the pointers */
     54     int16_t reserved;           /* reserved - for good alignment of the pointers */
     55     uint32_t options;
     56     const char *pkg, *name, *locale;
     57 } UConverterLoadArgs;
     58 
     59 typedef void (*UConverterLoad) (UConverterSharedData *sharedData,
     60                                 UConverterLoadArgs *pArgs,
     61                                 const uint8_t *raw, UErrorCode *pErrorCode);
     62 typedef void (*UConverterUnload) (UConverterSharedData *sharedData);
     63 
     64 typedef void (*UConverterOpen) (UConverter *cnv, UConverterLoadArgs *pArgs, UErrorCode *pErrorCode);
     65 typedef void (*UConverterClose) (UConverter *cnv);
     66 
     67 typedef enum UConverterResetChoice {
     68     UCNV_RESET_BOTH,
     69     UCNV_RESET_TO_UNICODE,
     70     UCNV_RESET_FROM_UNICODE
     71 } UConverterResetChoice;
     72 
     73 typedef void (*UConverterReset) (UConverter *cnv, UConverterResetChoice choice);
     74 
     75 /*
     76  * Converter implementation function(s) for ucnv_toUnicode().
     77  * If the toUnicodeWithOffsets function pointer is NULL,
     78  * then the toUnicode function will be used and the offsets will be set to -1.
     79  *
     80  * Must maintain state across buffers. Use toUBytes[toULength] for partial input
     81  * sequences; it will be checked in ucnv.c at the end of the input stream
     82  * to detect truncated input.
     83  * Some converters may need additional detection and may then set U_TRUNCATED_CHAR_FOUND.
     84  *
     85  * The toUnicodeWithOffsets must write exactly as many offset values as target
     86  * units. Write offset values of -1 for when the source index corresponding to
     87  * the output unit is not known (e.g., the character started in an earlier buffer).
     88  * The pArgs->offsets pointer need not be moved forward.
     89  *
     90  * At function return, either one of the following conditions must be true:
     91  * - U_BUFFER_OVERFLOW_ERROR and the target is full: target==targetLimit
     92  * - another error code with toUBytes[toULength] set to the offending input
     93  * - no error, and the source is consumed: source==sourceLimit
     94  *
     95  * The ucnv.c code will handle the end of the input (reset)
     96  * (reset, and truncation detection) and callbacks.
     97  */
     98 typedef void (*UConverterToUnicode) (UConverterToUnicodeArgs *, UErrorCode *);
     99 
    100 /*
    101  * Same rules as for UConverterToUnicode.
    102  * A lead surrogate is kept in fromUChar32 across buffers, and if an error
    103  * occurs, then the offending input code point must be put into fromUChar32
    104  * as well.
    105  */
    106 typedef void (*UConverterFromUnicode) (UConverterFromUnicodeArgs *, UErrorCode *);
    107 
    108 /*
    109  * Converter implementation function for ucnv_convertEx(), for direct conversion
    110  * between two charsets without pivoting through UTF-16.
    111  * The rules are the same as for UConverterToUnicode and UConverterFromUnicode.
    112  * In addition,
    113  * - The toUnicode side must behave and keep state exactly like the
    114  *   UConverterToUnicode implementation for the same source charset.
    115  * - A U_USING_DEFAULT_WARNING can be set to request to temporarily fall back
    116  *   to pivoting. When this function is called, the conversion framework makes
    117  *   sure that this warning is not set on input.
    118  * - Continuing a partial match and flushing the toUnicode replay buffer
    119  *   are handled by pivoting, using the toUnicode and fromUnicode functions.
    120  */
    121 typedef void (*UConverterConvert) (UConverterFromUnicodeArgs *pFromUArgs,
    122                                    UConverterToUnicodeArgs *pToUArgs,
    123                                    UErrorCode *pErrorCode);
    124 
    125 /*
    126  * Converter implementation function for ucnv_getNextUChar().
    127  * If the function pointer is NULL, then the toUnicode function will be used.
    128  *
    129  * Will be called at a character boundary (toULength==0).
    130  * May return with
    131  * - U_INDEX_OUTOFBOUNDS_ERROR if there was no output for the input
    132  *   (the return value will be ignored)
    133  * - U_TRUNCATED_CHAR_FOUND or another error code (never U_BUFFER_OVERFLOW_ERROR!)
    134  *   with toUBytes[toULength] set to the offending input
    135  *   (the return value will be ignored)
    136  * - return UCNV_GET_NEXT_UCHAR_USE_TO_U, without moving the source pointer,
    137  *   to indicate that the ucnv.c code shall call the toUnicode function instead
    138  * - return a real code point result
    139  *
    140  * Unless UCNV_GET_NEXT_UCHAR_USE_TO_U is returned, the source bytes must be consumed.
    141  *
    142  * The ucnv.c code will handle the end of the input (reset)
    143  * (except for truncation detection!) and callbacks.
    144  */
    145 typedef UChar32 (*UConverterGetNextUChar) (UConverterToUnicodeArgs *, UErrorCode *);
    146 
    147 typedef void (*UConverterGetStarters)(const UConverter* converter,
    148                                       UBool starters[256],
    149                                       UErrorCode *pErrorCode);
    150 
    151 /* If this function pointer is null or if the function returns null
    152  * the name field in static data struct should be returned by
    153  * ucnv_getName() API function
    154  */
    155 typedef const char * (*UConverterGetName) (const UConverter *cnv);
    156 
    157 /**
    158  * Write the codepage substitution character.
    159  * If this function is not set, then ucnv_cbFromUWriteSub() writes
    160  * the substitution character from UConverter.
    161  * For stateful converters, it is typically necessary to handle this
    162  * specificially for the converter in order to properly maintain the state.
    163  */
    164 typedef void (*UConverterWriteSub) (UConverterFromUnicodeArgs *pArgs, int32_t offsetIndex, UErrorCode *pErrorCode);
    165 
    166 /**
    167  * For converter-specific safeClone processing
    168  * If this function is not set, then ucnv_safeClone assumes that the converter has no private data that changes
    169  * after the converter is done opening.
    170  * If this function is set, then it is called just after a memcpy() of
    171  * converter data to the new, empty converter, and is expected to set up
    172  * the initial state of the converter.  It is not expected to increment the
    173  * reference counts of the standard data types such as the shared data.
    174  */
    175 typedef UConverter * (*UConverterSafeClone) (const UConverter   *cnv,
    176                                              void               *stackBuffer,
    177                                              int32_t            *pBufferSize,
    178                                              UErrorCode         *status);
    179 
    180 /**
    181  * Filters for some ucnv_getUnicodeSet() implementation code.
    182  */
    183 typedef enum UConverterSetFilter {
    184     UCNV_SET_FILTER_NONE,
    185     UCNV_SET_FILTER_DBCS_ONLY,
    186     UCNV_SET_FILTER_2022_CN,
    187     UCNV_SET_FILTER_SJIS,
    188     UCNV_SET_FILTER_GR94DBCS,
    189     UCNV_SET_FILTER_HZ,
    190     UCNV_SET_FILTER_COUNT
    191 } UConverterSetFilter;
    192 
    193 /**
    194  * Fills the set of Unicode code points that can be converted by an ICU converter.
    195  * The API function ucnv_getUnicodeSet() clears the USet before calling
    196  * the converter's getUnicodeSet() implementation; the converter should only
    197  * add the appropriate code points to allow recursive use.
    198  * For example, the ISO-2022-JP converter will call each subconverter's
    199  * getUnicodeSet() implementation to consecutively add code points to
    200  * the same USet, which will result in a union of the sets of all subconverters.
    201  *
    202  * For more documentation, see ucnv_getUnicodeSet() in ucnv.h.
    203  */
    204 typedef void (*UConverterGetUnicodeSet) (const UConverter *cnv,
    205                                          const USetAdder *sa,
    206                                          UConverterUnicodeSet which,
    207                                          UErrorCode *pErrorCode);
    208 
    209 UBool CONVERSION_U_SUCCESS (UErrorCode err);
    210 
    211 /**
    212  * UConverterImpl contains all the data and functions for a converter type.
    213  * Its function pointers work much like a C++ vtable.
    214  * Many converter types need to define only a subset of the functions;
    215  * when a function pointer is NULL, then a default action will be performed.
    216  *
    217  * Every converter type must implement toUnicode, fromUnicode, and getNextUChar,
    218  * otherwise the converter may crash.
    219  * Every converter type that has variable-length codepage sequences should
    220  * also implement toUnicodeWithOffsets and fromUnicodeWithOffsets for
    221  * correct offset handling.
    222  * All other functions may or may not be implemented - it depends only on
    223  * whether the converter type needs them.
    224  *
    225  * When open() fails, then close() will be called, if present.
    226  */
    227 struct UConverterImpl {
    228     UConverterType type;
    229 
    230     UConverterLoad load;
    231     UConverterUnload unload;
    232 
    233     UConverterOpen open;
    234     UConverterClose close;
    235     UConverterReset reset;
    236 
    237     UConverterToUnicode toUnicode;
    238     UConverterToUnicode toUnicodeWithOffsets;
    239     UConverterFromUnicode fromUnicode;
    240     UConverterFromUnicode fromUnicodeWithOffsets;
    241     UConverterGetNextUChar getNextUChar;
    242 
    243     UConverterGetStarters getStarters;
    244     UConverterGetName getName;
    245     UConverterWriteSub writeSub;
    246     UConverterSafeClone safeClone;
    247     UConverterGetUnicodeSet getUnicodeSet;
    248 
    249     UConverterConvert toUTF8;
    250     UConverterConvert fromUTF8;
    251 };
    252 
    253 extern const UConverterSharedData
    254     _MBCSData, _Latin1Data,
    255     _UTF8Data, _UTF16BEData, _UTF16LEData, _UTF32BEData, _UTF32LEData,
    256     _ISO2022Data,
    257     _LMBCSData1,_LMBCSData2, _LMBCSData3, _LMBCSData4, _LMBCSData5, _LMBCSData6,
    258     _LMBCSData8,_LMBCSData11,_LMBCSData16,_LMBCSData17,_LMBCSData18,_LMBCSData19,
    259     _HZData,_ISCIIData, _SCSUData, _ASCIIData,
    260     _UTF7Data, _Bocu1Data, _UTF16Data, _UTF32Data, _CESU8Data, _IMAPData, _CompoundTextData;
    261 
    262 U_CDECL_END
    263 
    264 /** Always use fallbacks from codepage to Unicode */
    265 #define TO_U_USE_FALLBACK(useFallback) TRUE
    266 #define UCNV_TO_U_USE_FALLBACK(cnv) TRUE
    267 
    268 /** Use fallbacks from Unicode to codepage when cnv->useFallback or for private-use code points */
    269 #define IS_PRIVATE_USE(c) ((uint32_t)((c)-0xe000)<0x1900 || (uint32_t)((c)-0xf0000)<0x20000)
    270 #define FROM_U_USE_FALLBACK(useFallback, c) ((useFallback) || IS_PRIVATE_USE(c))
    271 #define UCNV_FROM_U_USE_FALLBACK(cnv, c) FROM_U_USE_FALLBACK((cnv)->useFallback, c)
    272 
    273 /**
    274  * Magic number for ucnv_getNextUChar(), returned by a
    275  * getNextUChar() implementation to indicate to use the converter's toUnicode()
    276  * instead of the native function.
    277  * @internal
    278  */
    279 #define UCNV_GET_NEXT_UCHAR_USE_TO_U -9
    280 
    281 U_CFUNC void
    282 ucnv_getCompleteUnicodeSet(const UConverter *cnv,
    283                    const USetAdder *sa,
    284                    UConverterUnicodeSet which,
    285                    UErrorCode *pErrorCode);
    286 
    287 U_CFUNC void
    288 ucnv_getNonSurrogateUnicodeSet(const UConverter *cnv,
    289                                const USetAdder *sa,
    290                                UConverterUnicodeSet which,
    291                                UErrorCode *pErrorCode);
    292 
    293 U_CFUNC void
    294 ucnv_fromUWriteBytes(UConverter *cnv,
    295                      const char *bytes, int32_t length,
    296                      char **target, const char *targetLimit,
    297                      int32_t **offsets,
    298                      int32_t sourceIndex,
    299                      UErrorCode *pErrorCode);
    300 U_CFUNC void
    301 ucnv_toUWriteUChars(UConverter *cnv,
    302                     const UChar *uchars, int32_t length,
    303                     UChar **target, const UChar *targetLimit,
    304                     int32_t **offsets,
    305                     int32_t sourceIndex,
    306                     UErrorCode *pErrorCode);
    307 
    308 U_CFUNC void
    309 ucnv_toUWriteCodePoint(UConverter *cnv,
    310                        UChar32 c,
    311                        UChar **target, const UChar *targetLimit,
    312                        int32_t **offsets,
    313                        int32_t sourceIndex,
    314                        UErrorCode *pErrorCode);
    315 
    316 #endif
    317 
    318 #endif /* UCNV_CNV */
    319