source/common/messagepattern.cpp

   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) 2011-2012, International Business Machines
   6 *   Corporation and others.  All Rights Reserved.
   7 *******************************************************************************
   8 *   file name:  messagepattern.cpp
   9 *   encoding:   US-ASCII
  10 *   tab size:   8 (not used)
  11 *   indentation:4
  12 *
  13 *   created on: 2011mar14
  14 *   created by: Markus W. Scherer
  15 */
  16
  17 #include "unicode/utypes.h"
  18
  19 #if !UCONFIG_NO_FORMATTING
  20
  21 #include "unicode/messagepattern.h"
  22 #include "unicode/unistr.h"
  23 #include "unicode/utf16.h"
  24 #include "cmemory.h"
  25 #include "cstring.h"
  26 #include "messageimpl.h"
  27 #include "patternprops.h"
  28 #include "putilimp.h"
  29 #include "uassert.h"
  30
  31 U_NAMESPACE_BEGIN
  32
  33 // Unicode character/code point constants ---------------------------------- ***
  34
  35 static const UChar u_pound=0x23;
  36 static const UChar u_apos=0x27;
  37 static const UChar u_plus=0x2B;
  38 static const UChar u_comma=0x2C;
  39 static const UChar u_minus=0x2D;
  40 static const UChar u_dot=0x2E;
  41 static const UChar u_colon=0x3A;
  42 static const UChar u_lessThan=0x3C;
  43 static const UChar u_equal=0x3D;
  44 static const UChar u_A=0x41;
  45 static const UChar u_C=0x43;
  46 static const UChar u_D=0x44;
  47 static const UChar u_E=0x45;
  48 static const UChar u_H=0x48;
  49 static const UChar u_I=0x49;
  50 static const UChar u_L=0x4C;
  51 static const UChar u_N=0x4E;
  52 static const UChar u_O=0x4F;
  53 static const UChar u_P=0x50;
  54 static const UChar u_R=0x52;
  55 static const UChar u_S=0x53;
  56 static const UChar u_T=0x54;
  57 static const UChar u_U=0x55;
  58 static const UChar u_Z=0x5A;
  59 static const UChar u_a=0x61;
  60 static const UChar u_c=0x63;
  61 static const UChar u_d=0x64;
  62 static const UChar u_e=0x65;
  63 static const UChar u_f=0x66;
  64 static const UChar u_h=0x68;
  65 static const UChar u_i=0x69;
  66 static const UChar u_l=0x6C;
  67 static const UChar u_n=0x6E;
  68 static const UChar u_o=0x6F;
  69 static const UChar u_p=0x70;
  70 static const UChar u_r=0x72;
  71 static const UChar u_s=0x73;
  72 static const UChar u_t=0x74;
  73 static const UChar u_u=0x75;
  74 static const UChar u_z=0x7A;
  75 static const UChar u_leftCurlyBrace=0x7B;
  76 static const UChar u_pipe=0x7C;
  77 static const UChar u_rightCurlyBrace=0x7D;
  78 static const UChar u_lessOrEqual=0x2264;  // U+2264 is <=
  79
  80 static const UChar kOffsetColon[]={  // "offset:"
  81     u_o, u_f, u_f, u_s, u_e, u_t, u_colon
  82 };
  83
  84 static const UChar kOther[]={  // "other"
  85     u_o, u_t, u_h, u_e, u_r
  86 };
  87
  88 // MessagePatternList ------------------------------------------------------ ***
  89
  90 template<typename T, int32_t stackCapacity>
  91 class MessagePatternList : public UMemory {
  92 public:
  93     MessagePatternList() {}
  94     void copyFrom(const MessagePatternList<T, stackCapacity> &other,
  95                   int32_t length,
  96                   UErrorCode &errorCode);
  97     UBool ensureCapacityForOneMore(int32_t oldLength, UErrorCode &errorCode);
  98     UBool equals(const MessagePatternList<T, stackCapacity> &other, int32_t length) const {
  99         for(int32_t i=0; i<length; ++i) {
 100             if(a[i]!=other.a[i]) { return FALSE; }
 101         }
 102         return TRUE;
 103     }
 104
 105     MaybeStackArray<T, stackCapacity> a;
 106 };
 107
 108 template<typename T, int32_t stackCapacity>
 109 void
 110 MessagePatternList<T, stackCapacity>::copyFrom(
 111         const MessagePatternList<T, stackCapacity> &other,
 112         int32_t length,
 113         UErrorCode &errorCode) {
 114     if(U_SUCCESS(errorCode) && length>0) {
 115         if(length>a.getCapacity() && NULL==a.resize(length)) {
 116             errorCode=U_MEMORY_ALLOCATION_ERROR;
 117             return;
 118         }
 119         uprv_memcpy(a.getAlias(), other.a.getAlias(), (size_t)length*sizeof(T));
 120     }
 121 }
 122
 123 template<typename T, int32_t stackCapacity>
 124 UBool
 125 MessagePatternList<T, stackCapacity>::ensureCapacityForOneMore(int32_t oldLength, UErrorCode &errorCode) {
 126     if(U_FAILURE(errorCode)) {
 127         return FALSE;
 128     }
 129     if(a.getCapacity()>oldLength || a.resize(2*oldLength, oldLength)!=NULL) {
 130         return TRUE;
 131     }
 132     errorCode=U_MEMORY_ALLOCATION_ERROR;
 133     return FALSE;
 134 }
 135
 136 // MessagePatternList specializations -------------------------------------- ***
 137
 138 class MessagePatternDoubleList : public MessagePatternList<double, 8> {
 139 };
 140
 141 class MessagePatternPartsList : public MessagePatternList<MessagePattern::Part, 32> {
 142 };
 143
 144 // MessagePattern constructors etc. ---------------------------------------- ***
 145
 146 MessagePattern::MessagePattern(UErrorCode &errorCode)
 147         : aposMode(UCONFIG_MSGPAT_DEFAULT_APOSTROPHE_MODE),
 148           partsList(NULL), parts(NULL), partsLength(0),
 149           numericValuesList(NULL), numericValues(NULL), numericValuesLength(0),
 150           hasArgNames(FALSE), hasArgNumbers(FALSE), needsAutoQuoting(FALSE) {
 151     init(errorCode);
 152 }
 153
 154 MessagePattern::MessagePattern(UMessagePatternApostropheMode mode, UErrorCode &errorCode)
 155         : aposMode(mode),
 156           partsList(NULL), parts(NULL), partsLength(0),
 157           numericValuesList(NULL), numericValues(NULL), numericValuesLength(0),
 158           hasArgNames(FALSE), hasArgNumbers(FALSE), needsAutoQuoting(FALSE) {
 159     init(errorCode);
 160 }
 161
 162 MessagePattern::MessagePattern(const UnicodeString &pattern, UParseError *parseError, UErrorCode &errorCode)
 163         : aposMode(UCONFIG_MSGPAT_DEFAULT_APOSTROPHE_MODE),
 164           partsList(NULL), parts(NULL), partsLength(0),
 165           numericValuesList(NULL), numericValues(NULL), numericValuesLength(0),
 166           hasArgNames(FALSE), hasArgNumbers(FALSE), needsAutoQuoting(FALSE) {
 167     if(init(errorCode)) {
 168         parse(pattern, parseError, errorCode);
 169     }
 170 }
 171
 172 UBool
 173 MessagePattern::init(UErrorCode &errorCode) {
 174     if(U_FAILURE(errorCode)) {
 175         return FALSE;
 176     }
 177     partsList=new MessagePatternPartsList();
 178     if(partsList==NULL) {
 179         errorCode=U_MEMORY_ALLOCATION_ERROR;
 180         return FALSE;
 181     }
 182     parts=partsList->a.getAlias();
 183     return TRUE;
 184 }
 185
 186 MessagePattern::MessagePattern(const MessagePattern &other)
 187         : UObject(other), aposMode(other.aposMode), msg(other.msg),
 188           partsList(NULL), parts(NULL), partsLength(0),
 189           numericValuesList(NULL), numericValues(NULL), numericValuesLength(0),
 190           hasArgNames(other.hasArgNames), hasArgNumbers(other.hasArgNumbers),
 191           needsAutoQuoting(other.needsAutoQuoting) {
 192     UErrorCode errorCode=U_ZERO_ERROR;
 193     if(!copyStorage(other, errorCode)) {
 194         clear();
 195     }
 196 }
 197
 198 MessagePattern &
 199 MessagePattern::operator=(const MessagePattern &other) {
 200     if(this==&other) {
 201         return *this;
 202     }
 203     aposMode=other.aposMode;
 204     msg=other.msg;
 205     hasArgNames=other.hasArgNames;
 206     hasArgNumbers=other.hasArgNumbers;
 207     needsAutoQuoting=other.needsAutoQuoting;
 208     UErrorCode errorCode=U_ZERO_ERROR;
 209     if(!copyStorage(other, errorCode)) {
 210         clear();
 211     }
 212     return *this;
 213 }
 214
 215 UBool
 216 MessagePattern::copyStorage(const MessagePattern &other, UErrorCode &errorCode) {
 217     if(U_FAILURE(errorCode)) {
 218         return FALSE;
 219     }
 220     parts=NULL;
 221     partsLength=0;
 222     numericValues=NULL;
 223     numericValuesLength=0;
 224     if(partsList==NULL) {
 225         partsList=new MessagePatternPartsList();
 226         if(partsList==NULL) {
 227             errorCode=U_MEMORY_ALLOCATION_ERROR;
 228             return FALSE;
 229         }
 230         parts=partsList->a.getAlias();
 231     }
 232     if(other.partsLength>0) {
 233         partsList->copyFrom(*other.partsList, other.partsLength, errorCode);
 234         if(U_FAILURE(errorCode)) {
 235             return FALSE;
 236         }
 237         parts=partsList->a.getAlias();
 238         partsLength=other.partsLength;
 239     }
 240     if(other.numericValuesLength>0) {
 241         if(numericValuesList==NULL) {
 242             numericValuesList=new MessagePatternDoubleList();
 243             if(numericValuesList==NULL) {
 244                 errorCode=U_MEMORY_ALLOCATION_ERROR;
 245                 return FALSE;
 246             }
 247             numericValues=numericValuesList->a.getAlias();
 248         }
 249         numericValuesList->copyFrom(
 250             *other.numericValuesList, other.numericValuesLength, errorCode);
 251         if(U_FAILURE(errorCode)) {
 252             return FALSE;
 253         }
 254         numericValues=numericValuesList->a.getAlias();
 255         numericValuesLength=other.numericValuesLength;
 256     }
 257     return TRUE;
 258 }
 259
 260 MessagePattern::~MessagePattern() {
 261     delete partsList;
 262     delete numericValuesList;
 263 }
 264
 265 // MessagePattern API ------------------------------------------------------ ***
 266
 267 MessagePattern &
 268 MessagePattern::parse(const UnicodeString &pattern, UParseError *parseError, UErrorCode &errorCode) {
 269     preParse(pattern, parseError, errorCode);
 270     parseMessage(0, 0, 0, UMSGPAT_ARG_TYPE_NONE, parseError, errorCode);
 271     postParse();
 272     return *this;
 273 }
 274
 275 MessagePattern &
 276 MessagePattern::parseChoiceStyle(const UnicodeString &pattern,
 277                                  UParseError *parseError, UErrorCode &errorCode) {
 278     preParse(pattern, parseError, errorCode);
 279     parseChoiceStyle(0, 0, parseError, errorCode);
 280     postParse();
 281     return *this;
 282 }
 283
 284 MessagePattern &
 285 MessagePattern::parsePluralStyle(const UnicodeString &pattern,
 286                                  UParseError *parseError, UErrorCode &errorCode) {
 287     preParse(pattern, parseError, errorCode);
 288     parsePluralOrSelectStyle(UMSGPAT_ARG_TYPE_PLURAL, 0, 0, parseError, errorCode);
 289     postParse();
 290     return *this;
 291 }
 292
 293 MessagePattern &
 294 MessagePattern::parseSelectStyle(const UnicodeString &pattern,
 295                                  UParseError *parseError, UErrorCode &errorCode) {
 296     preParse(pattern, parseError, errorCode);
 297     parsePluralOrSelectStyle(UMSGPAT_ARG_TYPE_SELECT, 0, 0, parseError, errorCode);
 298     postParse();
 299     return *this;
 300 }
 301
 302 void
 303 MessagePattern::clear() {
 304     // Mostly the same as preParse().
 305     msg.remove();
 306     hasArgNames=hasArgNumbers=FALSE;
 307     needsAutoQuoting=FALSE;
 308     partsLength=0;
 309     numericValuesLength=0;
 310 }
 311
 312 UBool
 313 MessagePattern::operator==(const MessagePattern &other) const {
 314     if(this==&other) {
 315         return TRUE;
 316     }
 317     return
 318         aposMode==other.aposMode &&
 319         msg==other.msg &&
 320         // parts.equals(o.parts)
 321         partsLength==other.partsLength &&
 322         (partsLength==0 || partsList->equals(*other.partsList, partsLength));
 323     // No need to compare numericValues if msg and parts are the same.
 324 }
 325
 326 int32_t
 327 MessagePattern::hashCode() const {
 328     int32_t hash=(aposMode*37+msg.hashCode())*37+partsLength;
 329     for(int32_t i=0; i<partsLength; ++i) {
 330         hash=hash*37+parts[i].hashCode();
 331     }
 332     return hash;
 333 }
 334
 335 int32_t
 336 MessagePattern::validateArgumentName(const UnicodeString &name) {
 337     if(!PatternProps::isIdentifier(name.getBuffer(), name.length())) {
 338         return UMSGPAT_ARG_NAME_NOT_VALID;
 339     }
 340     return parseArgNumber(name, 0, name.length());
 341 }
 342
 343 UnicodeString
 344 MessagePattern::autoQuoteApostropheDeep() const {
 345     if(!needsAutoQuoting) {
 346         return msg;
 347     }
 348     UnicodeString modified(msg);
 349     // Iterate backward so that the insertion indexes do not change.
 350     int32_t count=countParts();
 351     for(int32_t i=count; i>0;) {
 352         const Part &part=getPart(--i);
 353         if(part.getType()==UMSGPAT_PART_TYPE_INSERT_CHAR) {
 354            modified.insert(part.index, (UChar)part.value);
 355         }
 356     }
 357     return modified;
 358 }
 359
 360 double
 361 MessagePattern::getNumericValue(const Part &part) const {
 362     UMessagePatternPartType type=part.type;
 363     if(type==UMSGPAT_PART_TYPE_ARG_INT) {
 364         return part.value;
 365     } else if(type==UMSGPAT_PART_TYPE_ARG_DOUBLE) {
 366         return numericValues[part.value];
 367     } else {
 368         return UMSGPAT_NO_NUMERIC_VALUE;
 369     }
 370 }
 371
 372 /**
 373   * Returns the "offset:" value of a PluralFormat argument, or 0 if none is specified.
 374   * @param pluralStart the index of the first PluralFormat argument style part. (0..countParts()-1)
 375   * @return the "offset:" value.
 376   * @draft ICU 4.8
 377   */
 378 double
 379 MessagePattern::getPluralOffset(int32_t pluralStart) const {
 380     const Part &part=getPart(pluralStart);
 381     if(Part::hasNumericValue(part.type)) {
 382         return getNumericValue(part);
 383     } else {
 384         return 0;
 385     }
 386 }
 387
 388 // MessagePattern::Part ---------------------------------------------------- ***
 389
 390 UBool
 391 MessagePattern::Part::operator==(const Part &other) const {
 392     if(this==&other) {
 393         return TRUE;
 394     }
 395     return
 396         type==other.type &&
 397         index==other.index &&
 398         length==other.length &&
 399         value==other.value &&
 400         limitPartIndex==other.limitPartIndex;
 401 }
 402
 403 // MessagePattern parser --------------------------------------------------- ***
 404
 405 void
 406 MessagePattern::preParse(const UnicodeString &pattern, UParseError *parseError, UErrorCode &errorCode) {
 407     if(U_FAILURE(errorCode)) {
 408         return;
 409     }
 410     if(parseError!=NULL) {
 411         parseError->line=0;
 412         parseError->offset=0;
 413         parseError->preContext[0]=0;
 414         parseError->postContext[0]=0;
 415     }
 416     msg=pattern;
 417     hasArgNames=hasArgNumbers=FALSE;
 418     needsAutoQuoting=FALSE;
 419     partsLength=0;
 420     numericValuesLength=0;
 421 }
 422
 423 void
 424 MessagePattern::postParse() {
 425     if(partsList!=NULL) {
 426         parts=partsList->a.getAlias();
 427     }
 428     if(numericValuesList!=NULL) {
 429         numericValues=numericValuesList->a.getAlias();
 430     }
 431 }
 432
 433 int32_t
 434 MessagePattern::parseMessage(int32_t index, int32_t msgStartLength,
 435                              int32_t nestingLevel, UMessagePatternArgType parentType,
 436                              UParseError *parseError, UErrorCode &errorCode) {
 437     if(U_FAILURE(errorCode)) {
 438         return 0;
 439     }
 440     if(nestingLevel>Part::MAX_VALUE) {
 441         errorCode=U_INDEX_OUTOFBOUNDS_ERROR;
 442         return 0;
 443     }
 444     int32_t msgStart=partsLength;
 445     addPart(UMSGPAT_PART_TYPE_MSG_START, index, msgStartLength, nestingLevel, errorCode);
 446     index+=msgStartLength;
 447     for(;;) {  // while(index<msg.length()) with U_FAILURE(errorCode) check
 448         if(U_FAILURE(errorCode)) {
 449             return 0;
 450         }
 451         if(index>=msg.length()) {
 452             break;
 453         }
 454         UChar c=msg.charAt(index++);
 455         if(c==u_apos) {
 456             if(index==msg.length()) {
 457                 // The apostrophe is the last character in the pattern.
 458                 // Add a Part for auto-quoting.
 459                 addPart(UMSGPAT_PART_TYPE_INSERT_CHAR, index, 0,
 460                         u_apos, errorCode);  // value=char to be inserted
 461                 needsAutoQuoting=TRUE;
 462             } else {
 463                 c=msg.charAt(index);
 464                 if(c==u_apos) {
 465                     // double apostrophe, skip the second one
 466                     addPart(UMSGPAT_PART_TYPE_SKIP_SYNTAX, index++, 1, 0, errorCode);
 467                 } else if(
 468                     aposMode==UMSGPAT_APOS_DOUBLE_REQUIRED ||
 469                     c==u_leftCurlyBrace || c==u_rightCurlyBrace ||
 470                     (parentType==UMSGPAT_ARG_TYPE_CHOICE && c==u_pipe) ||
 471                     (UMSGPAT_ARG_TYPE_HAS_PLURAL_STYLE(parentType) && c==u_pound)
 472                 ) {
 473                     // skip the quote-starting apostrophe
 474                     addPart(UMSGPAT_PART_TYPE_SKIP_SYNTAX, index-1, 1, 0, errorCode);
 475                     // find the end of the quoted literal text
 476                     for(;;) {
 477                         index=msg.indexOf(u_apos, index+1);
 478                         if(index>=0) {
 479                             if(/*(index+1)<msg.length() &&*/ msg.charAt(index+1)==u_apos) {
 480                                 // double apostrophe inside quoted literal text
 481                                 // still encodes a single apostrophe, skip the second one
 482                                 addPart(UMSGPAT_PART_TYPE_SKIP_SYNTAX, ++index, 1, 0, errorCode);
 483                             } else {
 484                                 // skip the quote-ending apostrophe
 485                                 addPart(UMSGPAT_PART_TYPE_SKIP_SYNTAX, index++, 1, 0, errorCode);
 486                                 break;
 487                             }
 488                         } else {
 489                             // The quoted text reaches to the end of the of the message.
 490                             index=msg.length();
 491                             // Add a Part for auto-quoting.
 492                             addPart(UMSGPAT_PART_TYPE_INSERT_CHAR, index, 0,
 493                                     u_apos, errorCode);  // value=char to be inserted
 494                             needsAutoQuoting=TRUE;
 495                             break;
 496                         }
 497                     }
 498                 } else {
 499                     // Interpret the apostrophe as literal text.
 500                     // Add a Part for auto-quoting.
 501                     addPart(UMSGPAT_PART_TYPE_INSERT_CHAR, index, 0,
 502                             u_apos, errorCode);  // value=char to be inserted
 503                     needsAutoQuoting=TRUE;
 504                 }
 505             }
 506         } else if(UMSGPAT_ARG_TYPE_HAS_PLURAL_STYLE(parentType) && c==u_pound) {
 507             // The unquoted # in a plural message fragment will be replaced
 508             // with the (number-offset).
 509             addPart(UMSGPAT_PART_TYPE_REPLACE_NUMBER, index-1, 1, 0, errorCode);
 510         } else if(c==u_leftCurlyBrace) {
 511             index=parseArg(index-1, 1, nestingLevel, parseError, errorCode);
 512         } else if((nestingLevel>0 && c==u_rightCurlyBrace) ||
 513                   (parentType==UMSGPAT_ARG_TYPE_CHOICE && c==u_pipe)) {
 514             // Finish the message before the terminator.
 515             // In a choice style, report the "}" substring only for the following ARG_LIMIT,
 516             // not for this MSG_LIMIT.
 517             int32_t limitLength=(parentType==UMSGPAT_ARG_TYPE_CHOICE && c==u_rightCurlyBrace) ? 0 : 1;
 518             addLimitPart(msgStart, UMSGPAT_PART_TYPE_MSG_LIMIT, index-1, limitLength,
 519                          nestingLevel, errorCode);
 520             if(parentType==UMSGPAT_ARG_TYPE_CHOICE) {
 521                 // Let the choice style parser see the '}' or '|'.
 522                 return index-1;
 523             } else {
 524                 // continue parsing after the '}'
 525                 return index;
 526             }
 527         }  // else: c is part of literal text
 528     }
 529     if(nestingLevel>0 && !inTopLevelChoiceMessage(nestingLevel, parentType)) {
 530         setParseError(parseError, 0);  // Unmatched '{' braces in message.
 531         errorCode=U_UNMATCHED_BRACES;
 532         return 0;
 533     }
 534     addLimitPart(msgStart, UMSGPAT_PART_TYPE_MSG_LIMIT, index, 0, nestingLevel, errorCode);
 535     return index;
 536 }
 537
 538 int32_t
 539 MessagePattern::parseArg(int32_t index, int32_t argStartLength, int32_t nestingLevel,
 540                          UParseError *parseError, UErrorCode &errorCode) {
 541     int32_t argStart=partsLength;
 542     UMessagePatternArgType argType=UMSGPAT_ARG_TYPE_NONE;
 543     addPart(UMSGPAT_PART_TYPE_ARG_START, index, argStartLength, argType, errorCode);
 544     if(U_FAILURE(errorCode)) {
 545         return 0;
 546     }
 547     int32_t nameIndex=index=skipWhiteSpace(index+argStartLength);
 548     if(index==msg.length()) {
 549         setParseError(parseError, 0);  // Unmatched '{' braces in message.
 550         errorCode=U_UNMATCHED_BRACES;
 551         return 0;
 552     }
 553     // parse argument name or number
 554     index=skipIdentifier(index);
 555     int32_t number=parseArgNumber(nameIndex, index);
 556     if(number>=0) {
 557         int32_t length=index-nameIndex;
 558         if(length>Part::MAX_LENGTH || number>Part::MAX_VALUE) {
 559             setParseError(parseError, nameIndex);  // Argument number too large.
 560             errorCode=U_INDEX_OUTOFBOUNDS_ERROR;
 561             return 0;
 562         }
 563         hasArgNumbers=TRUE;
 564         addPart(UMSGPAT_PART_TYPE_ARG_NUMBER, nameIndex, length, number, errorCode);
 565     } else if(number==UMSGPAT_ARG_NAME_NOT_NUMBER) {
 566         int32_t length=index-nameIndex;
 567         if(length>Part::MAX_LENGTH) {
 568             setParseError(parseError, nameIndex);  // Argument name too long.
 569             errorCode=U_INDEX_OUTOFBOUNDS_ERROR;
 570             return 0;
 571         }
 572         hasArgNames=TRUE;
 573         addPart(UMSGPAT_PART_TYPE_ARG_NAME, nameIndex, length, 0, errorCode);
 574     } else {  // number<-1 (ARG_NAME_NOT_VALID)
 575         setParseError(parseError, nameIndex);  // Bad argument syntax.
 576         errorCode=U_PATTERN_SYNTAX_ERROR;
 577         return 0;
 578     }
 579     index=skipWhiteSpace(index);
 580     if(index==msg.length()) {
 581         setParseError(parseError, 0);  // Unmatched '{' braces in message.
 582         errorCode=U_UNMATCHED_BRACES;
 583         return 0;
 584     }
 585     UChar c=msg.charAt(index);
 586     if(c==u_rightCurlyBrace) {
 587         // all done
 588     } else if(c!=u_comma) {
 589         setParseError(parseError, nameIndex);  // Bad argument syntax.
 590         errorCode=U_PATTERN_SYNTAX_ERROR;
 591         return 0;
 592     } else /* ',' */ {
 593         // parse argument type: case-sensitive a-zA-Z
 594         int32_t typeIndex=index=skipWhiteSpace(index+1);
 595         while(index<msg.length() && isArgTypeChar(msg.charAt(index))) {
 596             ++index;
 597         }
 598         int32_t length=index-typeIndex;
 599         index=skipWhiteSpace(index);
 600         if(index==msg.length()) {
 601             setParseError(parseError, 0);  // Unmatched '{' braces in message.
 602             errorCode=U_UNMATCHED_BRACES;
 603             return 0;
 604         }
 605         if(length==0 || ((c=msg.charAt(index))!=u_comma && c!=u_rightCurlyBrace)) {
 606             setParseError(parseError, nameIndex);  // Bad argument syntax.
 607             errorCode=U_PATTERN_SYNTAX_ERROR;
 608             return 0;
 609         }
 610         if(length>Part::MAX_LENGTH) {
 611             setParseError(parseError, nameIndex);  // Argument type name too long.
 612             errorCode=U_INDEX_OUTOFBOUNDS_ERROR;
 613             return 0;
 614         }
 615         argType=UMSGPAT_ARG_TYPE_SIMPLE;
 616         if(length==6) {
 617             // case-insensitive comparisons for complex-type names
 618             if(isChoice(typeIndex)) {
 619                 argType=UMSGPAT_ARG_TYPE_CHOICE;
 620             } else if(isPlural(typeIndex)) {
 621                 argType=UMSGPAT_ARG_TYPE_PLURAL;
 622             } else if(isSelect(typeIndex)) {
 623                 argType=UMSGPAT_ARG_TYPE_SELECT;
 624             }
 625         } else if(length==13) {
 626             if(isSelect(typeIndex) && isOrdinal(typeIndex+6)) {
 627                 argType=UMSGPAT_ARG_TYPE_SELECTORDINAL;
 628             }
 629         }
 630         // change the ARG_START type from NONE to argType
 631         partsList->a[argStart].value=(int16_t)argType;
 632         if(argType==UMSGPAT_ARG_TYPE_SIMPLE) {
 633             addPart(UMSGPAT_PART_TYPE_ARG_TYPE, typeIndex, length, 0, errorCode);
 634         }
 635         // look for an argument style (pattern)
 636         if(c==u_rightCurlyBrace) {
 637             if(argType!=UMSGPAT_ARG_TYPE_SIMPLE) {
 638                 setParseError(parseError, nameIndex);  // No style field for complex argument.
 639                 errorCode=U_PATTERN_SYNTAX_ERROR;
 640                 return 0;
 641             }
 642         } else /* ',' */ {
 643             ++index;
 644             if(argType==UMSGPAT_ARG_TYPE_SIMPLE) {
 645                 index=parseSimpleStyle(index, parseError, errorCode);
 646             } else if(argType==UMSGPAT_ARG_TYPE_CHOICE) {
 647                 index=parseChoiceStyle(index, nestingLevel, parseError, errorCode);
 648             } else {
 649                 index=parsePluralOrSelectStyle(argType, index, nestingLevel, parseError, errorCode);
 650             }
 651         }
 652     }
 653     // Argument parsing stopped on the '}'.
 654     addLimitPart(argStart, UMSGPAT_PART_TYPE_ARG_LIMIT, index, 1, argType, errorCode);
 655     return index+1;
 656 }
 657
 658 int32_t
 659 MessagePattern::parseSimpleStyle(int32_t index, UParseError *parseError, UErrorCode &errorCode) {
 660     if(U_FAILURE(errorCode)) {
 661         return 0;
 662     }
 663     int32_t start=index;
 664     int32_t nestedBraces=0;
 665     while(index<msg.length()) {
 666         UChar c=msg.charAt(index++);
 667         if(c==u_apos) {
 668             // Treat apostrophe as quoting but include it in the style part.
 669             // Find the end of the quoted literal text.
 670             index=msg.indexOf(u_apos, index);
 671             if(index<0) {
 672                 // Quoted literal argument style text reaches to the end of the message.
 673                 setParseError(parseError, start);
 674                 errorCode=U_PATTERN_SYNTAX_ERROR;
 675                 return 0;
 676             }
 677             // skip the quote-ending apostrophe
 678             ++index;
 679         } else if(c==u_leftCurlyBrace) {
 680             ++nestedBraces;
 681         } else if(c==u_rightCurlyBrace) {
 682             if(nestedBraces>0) {
 683                 --nestedBraces;
 684             } else {
 685                 int32_t length=--index-start;
 686                 if(length>Part::MAX_LENGTH) {
 687                     setParseError(parseError, start);  // Argument style text too long.
 688                     errorCode=U_INDEX_OUTOFBOUNDS_ERROR;
 689                     return 0;
 690                 }
 691                 addPart(UMSGPAT_PART_TYPE_ARG_STYLE, start, length, 0, errorCode);
 692                 return index;
 693             }
 694         }  // c is part of literal text
 695     }
 696     setParseError(parseError, 0);  // Unmatched '{' braces in message.
 697     errorCode=U_UNMATCHED_BRACES;
 698     return 0;
 699 }
 700
 701 int32_t
 702 MessagePattern::parseChoiceStyle(int32_t index, int32_t nestingLevel,
 703                                  UParseError *parseError, UErrorCode &errorCode) {
 704     if(U_FAILURE(errorCode)) {
 705         return 0;
 706     }
 707     int32_t start=index;
 708     index=skipWhiteSpace(index);
 709     if(index==msg.length() || msg.charAt(index)==u_rightCurlyBrace) {
 710         setParseError(parseError, 0);  // Missing choice argument pattern.
 711         errorCode=U_PATTERN_SYNTAX_ERROR;
 712         return 0;
 713     }
 714     for(;;) {
 715         // The choice argument style contains |-separated (number, separator, message) triples.
 716         // Parse the number.
 717         int32_t numberIndex=index;
 718         index=skipDouble(index);
 719         int32_t length=index-numberIndex;
 720         if(length==0) {
 721             setParseError(parseError, start);  // Bad choice pattern syntax.
 722             errorCode=U_PATTERN_SYNTAX_ERROR;
 723             return 0;
 724         }
 725         if(length>Part::MAX_LENGTH) {
 726             setParseError(parseError, numberIndex);  // Choice number too long.
 727             errorCode=U_INDEX_OUTOFBOUNDS_ERROR;
 728             return 0;
 729         }
 730         parseDouble(numberIndex, index, TRUE, parseError, errorCode);  // adds ARG_INT or ARG_DOUBLE
 731         if(U_FAILURE(errorCode)) {
 732             return 0;
 733         }
 734         // Parse the separator.
 735         index=skipWhiteSpace(index);
 736         if(index==msg.length()) {
 737             setParseError(parseError, start);  // Bad choice pattern syntax.
 738             errorCode=U_PATTERN_SYNTAX_ERROR;
 739             return 0;
 740         }
 741         UChar c=msg.charAt(index);
 742         if(!(c==u_pound || c==u_lessThan || c==u_lessOrEqual)) {  // U+2264 is <=
 743             setParseError(parseError, start);  // Expected choice separator (#<\u2264) instead of c.
 744             errorCode=U_PATTERN_SYNTAX_ERROR;
 745             return 0;
 746         }
 747         addPart(UMSGPAT_PART_TYPE_ARG_SELECTOR, index, 1, 0, errorCode);
 748         // Parse the message fragment.
 749         index=parseMessage(++index, 0, nestingLevel+1, UMSGPAT_ARG_TYPE_CHOICE, parseError, errorCode);
 750         if(U_FAILURE(errorCode)) {
 751             return 0;
 752         }
 753         // parseMessage(..., CHOICE) returns the index of the terminator, or msg.length().
 754         if(index==msg.length()) {
 755             return index;
 756         }
 757         if(msg.charAt(index)==u_rightCurlyBrace) {
 758             if(!inMessageFormatPattern(nestingLevel)) {
 759                 setParseError(parseError, start);  // Bad choice pattern syntax.
 760                 errorCode=U_PATTERN_SYNTAX_ERROR;
 761                 return 0;
 762             }
 763             return index;
 764         }  // else the terminator is '|'
 765         index=skipWhiteSpace(index+1);
 766     }
 767 }
 768
 769 int32_t
 770 MessagePattern::parsePluralOrSelectStyle(UMessagePatternArgType argType,
 771                                          int32_t index, int32_t nestingLevel,
 772                                          UParseError *parseError, UErrorCode &errorCode) {
 773     if(U_FAILURE(errorCode)) {
 774         return 0;
 775     }
 776     int32_t start=index;
 777     UBool isEmpty=TRUE;
 778     UBool hasOther=FALSE;
 779     for(;;) {
 780         // First, collect the selector looking for a small set of terminators.
 781         // It would be a little faster to consider the syntax of each possible
 782         // token right here, but that makes the code too complicated.
 783         index=skipWhiteSpace(index);
 784         UBool eos=index==msg.length();
 785         if(eos || msg.charAt(index)==u_rightCurlyBrace) {
 786             if(eos==inMessageFormatPattern(nestingLevel)) {
 787                 setParseError(parseError, start);  // Bad plural/select pattern syntax.
 788                 errorCode=U_PATTERN_SYNTAX_ERROR;
 789                 return 0;
 790             }
 791             if(!hasOther) {
 792                 setParseError(parseError, 0);  // Missing 'other' keyword in plural/select pattern.
 793                 errorCode=U_DEFAULT_KEYWORD_MISSING;
 794                 return 0;
 795             }
 796             return index;
 797         }
 798         int32_t selectorIndex=index;
 799         if(UMSGPAT_ARG_TYPE_HAS_PLURAL_STYLE(argType) && msg.charAt(selectorIndex)==u_equal) {
 800             // explicit-value plural selector: =double
 801             index=skipDouble(index+1);
 802             int32_t length=index-selectorIndex;
 803             if(length==1) {
 804                 setParseError(parseError, start);  // Bad plural/select pattern syntax.
 805                 errorCode=U_PATTERN_SYNTAX_ERROR;
 806                 return 0;
 807             }
 808             if(length>Part::MAX_LENGTH) {
 809                 setParseError(parseError, selectorIndex);  // Argument selector too long.
 810                 errorCode=U_INDEX_OUTOFBOUNDS_ERROR;
 811                 return 0;
 812             }
 813             addPart(UMSGPAT_PART_TYPE_ARG_SELECTOR, selectorIndex, length, 0, errorCode);
 814             parseDouble(selectorIndex+1, index, FALSE,
 815                         parseError, errorCode);  // adds ARG_INT or ARG_DOUBLE
 816         } else {
 817             index=skipIdentifier(index);
 818             int32_t length=index-selectorIndex;
 819             if(length==0) {
 820                 setParseError(parseError, start);  // Bad plural/select pattern syntax.
 821                 errorCode=U_PATTERN_SYNTAX_ERROR;
 822                 return 0;
 823             }
 824             // Note: The ':' in "offset:" is just beyond the skipIdentifier() range.
 825             if( UMSGPAT_ARG_TYPE_HAS_PLURAL_STYLE(argType) && length==6 && index<msg.length() &&
 826                 0==msg.compare(selectorIndex, 7, kOffsetColon, 0, 7)
 827             ) {
 828                 // plural offset, not a selector
 829                 if(!isEmpty) {
 830                     // Plural argument 'offset:' (if present) must precede key-message pairs.
 831                     setParseError(parseError, start);
 832                     errorCode=U_PATTERN_SYNTAX_ERROR;
 833                     return 0;
 834                 }
 835                 // allow whitespace between offset: and its value
 836                 int32_t valueIndex=skipWhiteSpace(index+1);  // The ':' is at index.
 837                 index=skipDouble(valueIndex);
 838                 if(index==valueIndex) {
 839                     setParseError(parseError, start);  // Missing value for plural 'offset:'.
 840                     errorCode=U_PATTERN_SYNTAX_ERROR;
 841                     return 0;
 842                 }
 843                 if((index-valueIndex)>Part::MAX_LENGTH) {
 844                     setParseError(parseError, valueIndex);  // Plural offset value too long.
 845                     errorCode=U_INDEX_OUTOFBOUNDS_ERROR;
 846                     return 0;
 847                 }
 848                 parseDouble(valueIndex, index, FALSE,
 849                             parseError, errorCode);  // adds ARG_INT or ARG_DOUBLE
 850                 if(U_FAILURE(errorCode)) {
 851                     return 0;
 852                 }
 853                 isEmpty=FALSE;
 854                 continue;  // no message fragment after the offset
 855             } else {
 856                 // normal selector word
 857                 if(length>Part::MAX_LENGTH) {
 858                     setParseError(parseError, selectorIndex);  // Argument selector too long.
 859                     errorCode=U_INDEX_OUTOFBOUNDS_ERROR;
 860                     return 0;
 861                 }
 862                 addPart(UMSGPAT_PART_TYPE_ARG_SELECTOR, selectorIndex, length, 0, errorCode);
 863                 if(0==msg.compare(selectorIndex, length, kOther, 0, 5)) {
 864                     hasOther=TRUE;
 865                 }
 866             }
 867         }
 868         if(U_FAILURE(errorCode)) {
 869             return 0;
 870         }
 871
 872         // parse the message fragment following the selector
 873         index=skipWhiteSpace(index);
 874         if(index==msg.length() || msg.charAt(index)!=u_leftCurlyBrace) {
 875             setParseError(parseError, selectorIndex);  // No message fragment after plural/select selector.
 876             errorCode=U_PATTERN_SYNTAX_ERROR;
 877             return 0;
 878         }
 879         index=parseMessage(index, 1, nestingLevel+1, argType, parseError, errorCode);
 880         if(U_FAILURE(errorCode)) {
 881             return 0;
 882         }
 883         isEmpty=FALSE;
 884     }
 885 }
 886
 887 int32_t
 888 MessagePattern::parseArgNumber(const UnicodeString &s, int32_t start, int32_t limit) {
 889     // If the identifier contains only ASCII digits, then it is an argument _number_
 890     // and must not have leading zeros (except "0" itself).
 891     // Otherwise it is an argument _name_.
 892     if(start>=limit) {
 893         return UMSGPAT_ARG_NAME_NOT_VALID;
 894     }
 895     int32_t number;
 896     // Defer numeric errors until we know there are only digits.
 897     UBool badNumber;
 898     UChar c=s.charAt(start++);
 899     if(c==0x30) {
 900         if(start==limit) {
 901             return 0;
 902         } else {
 903             number=0;
 904             badNumber=TRUE;  // leading zero
 905         }
 906     } else if(0x31<=c && c<=0x39) {
 907         number=c-0x30;
 908         badNumber=FALSE;
 909     } else {
 910         return UMSGPAT_ARG_NAME_NOT_NUMBER;
 911     }
 912     while(start<limit) {
 913         c=s.charAt(start++);
 914         if(0x30<=c && c<=0x39) {
 915             if(number>=INT32_MAX/10) {
 916                 badNumber=TRUE;  // overflow
 917             }
 918             number=number*10+(c-0x30);
 919         } else {
 920             return UMSGPAT_ARG_NAME_NOT_NUMBER;
 921         }
 922     }
 923     // There are only ASCII digits.
 924     if(badNumber) {
 925         return UMSGPAT_ARG_NAME_NOT_VALID;
 926     } else {
 927         return number;
 928     }
 929 }
 930
 931 void
 932 MessagePattern::parseDouble(int32_t start, int32_t limit, UBool allowInfinity,
 933                             UParseError *parseError, UErrorCode &errorCode) {
 934     if(U_FAILURE(errorCode)) {
 935         return;
 936     }
 937     U_ASSERT(start<limit);
 938     // fake loop for easy exit and single throw statement
 939     for(;;) { /*loop doesn't iterate*/
 940         // fast path for small integers and infinity
 941         int32_t value=0;
 942         int32_t isNegative=0;  // not boolean so that we can easily add it to value
 943         int32_t index=start;
 944         UChar c=msg.charAt(index++);
 945         if(c==u_minus) {
 946             isNegative=1;
 947             if(index==limit) {
 948                 break;  // no number
 949             }
 950             c=msg.charAt(index++);
 951         } else if(c==u_plus) {
 952             if(index==limit) {
 953                 break;  // no number
 954             }
 955             c=msg.charAt(index++);
 956         }
 957         if(c==0x221e) {  // infinity
 958             if(allowInfinity && index==limit) {
 959                 double infinity=uprv_getInfinity();
 960                 addArgDoublePart(
 961                     isNegative!=0 ? -infinity : infinity,
 962                     start, limit-start, errorCode);
 963                 return;
 964             } else {
 965                 break;
 966             }
 967         }
 968         // try to parse the number as a small integer but fall back to a double
 969         while('0'<=c && c<='9') {
 970             value=value*10+(c-'0');
 971             if(value>(Part::MAX_VALUE+isNegative)) {
 972                 break;  // not a small-enough integer
 973             }
 974             if(index==limit) {
 975                 addPart(UMSGPAT_PART_TYPE_ARG_INT, start, limit-start,
 976                         isNegative!=0 ? -value : value, errorCode);
 977                 return;
 978             }
 979             c=msg.charAt(index++);
 980         }
 981         // Let Double.parseDouble() throw a NumberFormatException.
 982         char numberChars[128];
 983         int32_t capacity=(int32_t)sizeof(numberChars);
 984         int32_t length=limit-start;
 985         if(length>=capacity) {
 986             break;  // number too long
 987         }
 988         msg.extract(start, length, numberChars, capacity, US_INV);
 989         if((int32_t)uprv_strlen(numberChars)<length) {
 990             break;  // contains non-invariant character that was turned into NUL
 991         }
 992         char *end;
 993         double numericValue=uprv_strtod(numberChars, &end);
 994         if(end!=(numberChars+length)) {
 995             break;  // parsing error
 996         }
 997         addArgDoublePart(numericValue, start, length, errorCode);
 998         return;
 999     }
1000     setParseError(parseError, start /*, limit*/);  // Bad syntax for numeric value.
1001     errorCode=U_PATTERN_SYNTAX_ERROR;
1002     return;
1003 }
1004
1005 int32_t
1006 MessagePattern::skipWhiteSpace(int32_t index) {
1007     const UChar *s=msg.getBuffer();
1008     int32_t msgLength=msg.length();
1009     const UChar *t=PatternProps::skipWhiteSpace(s+index, msgLength-index);
1010     return (int32_t)(t-s);
1011 }
1012
1013 int32_t
1014 MessagePattern::skipIdentifier(int32_t index) {
1015     const UChar *s=msg.getBuffer();
1016     int32_t msgLength=msg.length();
1017     const UChar *t=PatternProps::skipIdentifier(s+index, msgLength-index);
1018     return (int32_t)(t-s);
1019 }
1020
1021 int32_t
1022 MessagePattern::skipDouble(int32_t index) {
1023     int32_t msgLength=msg.length();
1024     while(index<msgLength) {
1025         UChar c=msg.charAt(index);
1026         // U+221E: Allow the infinity symbol, for ChoiceFormat patterns.
1027         if((c<0x30 && c!=u_plus && c!=u_minus && c!=u_dot) || (c>0x39 && c!=u_e && c!=u_E && c!=0x221e)) {
1028             break;
1029         }
1030         ++index;
1031     }
1032     return index;
1033 }
1034
1035 UBool
1036 MessagePattern::isArgTypeChar(UChar32 c) {
1037     return (u_a<=c && c<=u_z) || (u_A<=c && c<=u_Z);
1038 }
1039
1040 UBool
1041 MessagePattern::isChoice(int32_t index) {
1042     UChar c;
1043     return
1044         ((c=msg.charAt(index++))==u_c || c==u_C) &&
1045         ((c=msg.charAt(index++))==u_h || c==u_H) &&
1046         ((c=msg.charAt(index++))==u_o || c==u_O) &&
1047         ((c=msg.charAt(index++))==u_i || c==u_I) &&
1048         ((c=msg.charAt(index++))==u_c || c==u_C) &&
1049         ((c=msg.charAt(index))==u_e || c==u_E);
1050 }
1051
1052 UBool
1053 MessagePattern::isPlural(int32_t index) {
1054     UChar c;
1055     return
1056         ((c=msg.charAt(index++))==u_p || c==u_P) &&
1057         ((c=msg.charAt(index++))==u_l || c==u_L) &&
1058         ((c=msg.charAt(index++))==u_u || c==u_U) &&
1059         ((c=msg.charAt(index++))==u_r || c==u_R) &&
1060         ((c=msg.charAt(index++))==u_a || c==u_A) &&
1061         ((c=msg.charAt(index))==u_l || c==u_L);
1062 }
1063
1064 UBool
1065 MessagePattern::isSelect(int32_t index) {
1066     UChar c;
1067     return
1068         ((c=msg.charAt(index++))==u_s || c==u_S) &&
1069         ((c=msg.charAt(index++))==u_e || c==u_E) &&
1070         ((c=msg.charAt(index++))==u_l || c==u_L) &&
1071         ((c=msg.charAt(index++))==u_e || c==u_E) &&
1072         ((c=msg.charAt(index++))==u_c || c==u_C) &&
1073         ((c=msg.charAt(index))==u_t || c==u_T);
1074 }
1075
1076 UBool
1077 MessagePattern::isOrdinal(int32_t index) {
1078     UChar c;
1079     return
1080         ((c=msg.charAt(index++))==u_o || c==u_O) &&
1081         ((c=msg.charAt(index++))==u_r || c==u_R) &&
1082         ((c=msg.charAt(index++))==u_d || c==u_D) &&
1083         ((c=msg.charAt(index++))==u_i || c==u_I) &&
1084         ((c=msg.charAt(index++))==u_n || c==u_N) &&
1085         ((c=msg.charAt(index++))==u_a || c==u_A) &&
1086         ((c=msg.charAt(index))==u_l || c==u_L);
1087 }
1088
1089 UBool
1090 MessagePattern::inMessageFormatPattern(int32_t nestingLevel) {
1091     return nestingLevel>0 || partsList->a[0].type==UMSGPAT_PART_TYPE_MSG_START;
1092 }
1093
1094 UBool
1095 MessagePattern::inTopLevelChoiceMessage(int32_t nestingLevel, UMessagePatternArgType parentType) {
1096     return
1097         nestingLevel==1 &&
1098         parentType==UMSGPAT_ARG_TYPE_CHOICE &&
1099         partsList->a[0].type!=UMSGPAT_PART_TYPE_MSG_START;
1100 }
1101
1102 void
1103 MessagePattern::addPart(UMessagePatternPartType type, int32_t index, int32_t length,
1104                         int32_t value, UErrorCode &errorCode) {
1105     if(partsList->ensureCapacityForOneMore(partsLength, errorCode)) {
1106         Part &part=partsList->a[partsLength++];
1107         part.type=type;
1108         part.index=index;
1109         part.length=(uint16_t)length;
1110         part.value=(int16_t)value;
1111         part.limitPartIndex=0;
1112     }
1113 }
1114
1115 void
1116 MessagePattern::addLimitPart(int32_t start,
1117                              UMessagePatternPartType type, int32_t index, int32_t length,
1118                              int32_t value, UErrorCode &errorCode) {
1119     partsList->a[start].limitPartIndex=partsLength;
1120     addPart(type, index, length, value, errorCode);
1121 }
1122
1123 void
1124 MessagePattern::addArgDoublePart(double numericValue, int32_t start, int32_t length,
1125                                  UErrorCode &errorCode) {
1126     if(U_FAILURE(errorCode)) {
1127         return;
1128     }
1129     int32_t numericIndex=numericValuesLength;
1130     if(numericValuesList==NULL) {
1131         numericValuesList=new MessagePatternDoubleList();
1132         if(numericValuesList==NULL) {
1133             errorCode=U_MEMORY_ALLOCATION_ERROR;
1134             return;
1135         }
1136     } else if(!numericValuesList->ensureCapacityForOneMore(numericValuesLength, errorCode)) {
1137         return;
1138     } else {
1139         if(numericIndex>Part::MAX_VALUE) {
1140             errorCode=U_INDEX_OUTOFBOUNDS_ERROR;
1141             return;
1142         }
1143     }
1144     numericValuesList->a[numericValuesLength++]=numericValue;
1145     addPart(UMSGPAT_PART_TYPE_ARG_DOUBLE, start, length, numericIndex, errorCode);
1146 }
1147
1148 void
1149 MessagePattern::setParseError(UParseError *parseError, int32_t index) {
1150     if(parseError==NULL) {
1151         return;
1152     }
1153     parseError->offset=index;
1154
1155     // Set preContext to some of msg before index.
1156     // Avoid splitting a surrogate pair.
1157     int32_t length=index;
1158     if(length>=U_PARSE_CONTEXT_LEN) {
1159         length=U_PARSE_CONTEXT_LEN-1;
1160         if(length>0 && U16_IS_TRAIL(msg[index-length])) {
1161             --length;
1162         }
1163     }
1164     msg.extract(index-length, length, parseError->preContext);
1165     parseError->preContext[length]=0;
1166
1167     // Set postContext to some of msg starting at index.
1168     length=msg.length()-index;
1169     if(length>=U_PARSE_CONTEXT_LEN) {
1170         length=U_PARSE_CONTEXT_LEN-1;
1171         if(length>0 && U16_IS_LEAD(msg[index+length-1])) {
1172             --length;
1173         }
1174     }
1175     msg.extract(index, length, parseError->postContext);
1176     parseError->postContext[length]=0;
1177 }
1178
1179 // MessageImpl ------------------------------------------------------------- ***
1180
1181 void
1182 MessageImpl::appendReducedApostrophes(const UnicodeString &s, int32_t start, int32_t limit,
1183                                       UnicodeString &sb) {
1184     int32_t doubleApos=-1;
1185     for(;;) {
1186         int32_t i=s.indexOf(u_apos, start);
1187         if(i<0 || i>=limit) {
1188             sb.append(s, start, limit-start);
1189             break;
1190         }
1191         if(i==doubleApos) {
1192             // Double apostrophe at start-1 and start==i, append one.
1193             sb.append(u_apos);
1194             ++start;
1195             doubleApos=-1;
1196         } else {
1197             // Append text between apostrophes and skip this one.
1198             sb.append(s, start, i-start);
1199             doubleApos=start=i+1;
1200         }
1201     }
1202 }
1203
1204 // Ported from second half of ICU4J SelectFormat.format(String).
1205 UnicodeString &
1206 MessageImpl::appendSubMessageWithoutSkipSyntax(const MessagePattern &msgPattern,
1207                                                int32_t msgStart,
1208                                                UnicodeString &result) {
1209     const UnicodeString &msgString=msgPattern.getPatternString();
1210     int32_t prevIndex=msgPattern.getPart(msgStart).getLimit();
1211     for(int32_t i=msgStart;;) {
1212         const MessagePattern::Part &part=msgPattern.getPart(++i);
1213         UMessagePatternPartType type=part.getType();
1214         int32_t index=part.getIndex();
1215         if(type==UMSGPAT_PART_TYPE_MSG_LIMIT) {
1216             return result.append(msgString, prevIndex, index-prevIndex);
1217         } else if(type==UMSGPAT_PART_TYPE_SKIP_SYNTAX) {
1218             result.append(msgString, prevIndex, index-prevIndex);
1219             prevIndex=part.getLimit();
1220         } else if(type==UMSGPAT_PART_TYPE_ARG_START) {
1221             result.append(msgString, prevIndex, index-prevIndex);
1222             prevIndex=index;
1223             i=msgPattern.getLimitPartIndex(i);
1224             index=msgPattern.getPart(i).getLimit();
1225             appendReducedApostrophes(msgString, prevIndex, index, result);
1226             prevIndex=index;
1227         }
1228     }
1229 }
1230
1231 U_NAMESPACE_END
1232
1233 #endif  // !UCONFIG_NO_FORMATTING