icuSources/common/ucnv_cnv.h

   1 // © 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 */