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      1 /*
      2  *******************************************************************************
      3  *
      4  *   Copyright (C) 2003-2014, International Business Machines
      5  *   Corporation and others.  All Rights Reserved.
      6  *
      7  *******************************************************************************
      8  *   file name:  uidna.cpp
      9  *   encoding:   US-ASCII
     10  *   tab size:   8 (not used)
     11  *   indentation:4
     12  *
     13  *   created on: 2003feb1
     14  *   created by: Ram Viswanadha
     15  */
     16 
     17 #include "unicode/utypes.h"
     18 
     19 #if !UCONFIG_NO_IDNA
     20 
     21 #include "unicode/uidna.h"
     22 #include "unicode/ustring.h"
     23 #include "unicode/usprep.h"
     24 #include "punycode.h"
     25 #include "ustr_imp.h"
     26 #include "cmemory.h"
     27 #include "uassert.h"
     28 #include "sprpimpl.h"
     29 
     30 /* it is official IDNA ACE Prefix is "xn--" */
     31 static const UChar ACE_PREFIX[] ={ 0x0078,0x006E,0x002d,0x002d } ;
     32 #define ACE_PREFIX_LENGTH 4
     33 
     34 #define MAX_LABEL_LENGTH 63
     35 /* The Max length of the labels should not be more than MAX_LABEL_LENGTH */
     36 #define MAX_LABEL_BUFFER_SIZE 100
     37 
     38 #define MAX_DOMAIN_NAME_LENGTH 255
     39 /* The Max length of the domain names should not be more than MAX_DOMAIN_NAME_LENGTH */
     40 #define MAX_IDN_BUFFER_SIZE   MAX_DOMAIN_NAME_LENGTH+1
     41 
     42 #define LOWER_CASE_DELTA 0x0020
     43 #define HYPHEN           0x002D
     44 #define FULL_STOP        0x002E
     45 #define CAPITAL_A        0x0041
     46 #define CAPITAL_Z        0x005A
     47 
     48 inline static UChar
     49 toASCIILower(UChar ch){
     50     if(CAPITAL_A <= ch && ch <= CAPITAL_Z){
     51         return ch + LOWER_CASE_DELTA;
     52     }
     53     return ch;
     54 }
     55 
     56 inline static UBool
     57 startsWithPrefix(const UChar* src , int32_t srcLength){
     58     UBool startsWithPrefix = TRUE;
     59 
     60     if(srcLength < ACE_PREFIX_LENGTH){
     61         return FALSE;
     62     }
     63 
     64     for(int8_t i=0; i< ACE_PREFIX_LENGTH; i++){
     65         if(toASCIILower(src[i]) != ACE_PREFIX[i]){
     66             startsWithPrefix = FALSE;
     67         }
     68     }
     69     return startsWithPrefix;
     70 }
     71 
     72 
     73 inline static int32_t
     74 compareCaseInsensitiveASCII(const UChar* s1, int32_t s1Len,
     75                             const UChar* s2, int32_t s2Len){
     76 
     77     int32_t minLength;
     78     int32_t lengthResult;
     79 
     80     // are we comparing different lengths?
     81     if(s1Len != s2Len) {
     82         if(s1Len < s2Len) {
     83             minLength = s1Len;
     84             lengthResult = -1;
     85         } else {
     86             minLength = s2Len;
     87             lengthResult = 1;
     88         }
     89     } else {
     90         // ok the lengths are equal
     91         minLength = s1Len;
     92         lengthResult = 0;
     93     }
     94 
     95     UChar c1,c2;
     96     int32_t rc;
     97 
     98     for(int32_t i =0;/* no condition */;i++) {
     99 
    100         /* If we reach the ends of both strings then they match */
    101         if(i == minLength) {
    102             return lengthResult;
    103         }
    104 
    105         c1 = s1[i];
    106         c2 = s2[i];
    107 
    108         /* Case-insensitive comparison */
    109         if(c1!=c2) {
    110             rc=(int32_t)toASCIILower(c1)-(int32_t)toASCIILower(c2);
    111             if(rc!=0) {
    112                 lengthResult=rc;
    113                 break;
    114             }
    115         }
    116     }
    117     return lengthResult;
    118 }
    119 
    120 
    121 /**
    122  * Ascertain if the given code point is a label separator as
    123  * defined by the IDNA RFC
    124  *
    125  * @param ch The code point to be ascertained
    126  * @return true if the char is a label separator
    127  * @stable ICU 2.8
    128  */
    129 static inline UBool isLabelSeparator(UChar ch){
    130     switch(ch){
    131         case 0x002e:
    132         case 0x3002:
    133         case 0xFF0E:
    134         case 0xFF61:
    135             return TRUE;
    136         default:
    137             return FALSE;
    138     }
    139 }
    140 
    141 // returns the length of the label excluding the separator
    142 // if *limit == separator then the length returned does not include
    143 // the separtor.
    144 static inline int32_t
    145 getNextSeparator(UChar *src, int32_t srcLength,
    146                  UChar **limit, UBool *done){
    147     if(srcLength == -1){
    148         int32_t i;
    149         for(i=0 ; ;i++){
    150             if(src[i] == 0){
    151                 *limit = src + i; // point to null
    152                 *done = TRUE;
    153                 return i;
    154             }
    155             if(isLabelSeparator(src[i])){
    156                 *limit = src + (i+1); // go past the delimiter
    157                 return i;
    158 
    159             }
    160         }
    161     }else{
    162         int32_t i;
    163         for(i=0;i<srcLength;i++){
    164             if(isLabelSeparator(src[i])){
    165                 *limit = src + (i+1); // go past the delimiter
    166                 return i;
    167             }
    168         }
    169         // we have not found the delimiter
    170         // if(i==srcLength)
    171         *limit = src+srcLength;
    172         *done = TRUE;
    173 
    174         return i;
    175     }
    176 }
    177 static inline UBool isLDHChar(UChar ch){
    178     // high runner case
    179     if(ch>0x007A){
    180         return FALSE;
    181     }
    182     //[\\u002D \\u0030-\\u0039 \\u0041-\\u005A \\u0061-\\u007A]
    183     if( (ch==0x002D) ||
    184         (0x0030 <= ch && ch <= 0x0039) ||
    185         (0x0041 <= ch && ch <= 0x005A) ||
    186         (0x0061 <= ch && ch <= 0x007A)
    187       ){
    188         return TRUE;
    189     }
    190     return FALSE;
    191 }
    192 
    193 static int32_t
    194 _internal_toASCII(const UChar* src, int32_t srcLength,
    195                   UChar* dest, int32_t destCapacity,
    196                   int32_t options,
    197                   UStringPrepProfile* nameprep,
    198                   UParseError* parseError,
    199                   UErrorCode* status)
    200 {
    201 
    202     // TODO Revisit buffer handling. The label should not be over 63 ASCII characters. ICU4J may need to be updated too.
    203     UChar b1Stack[MAX_LABEL_BUFFER_SIZE], b2Stack[MAX_LABEL_BUFFER_SIZE];
    204     //initialize pointers to stack buffers
    205     UChar  *b1 = b1Stack, *b2 = b2Stack;
    206     int32_t b1Len=0, b2Len,
    207             b1Capacity = MAX_LABEL_BUFFER_SIZE,
    208             b2Capacity = MAX_LABEL_BUFFER_SIZE ,
    209             reqLength=0;
    210 
    211     int32_t namePrepOptions = ((options & UIDNA_ALLOW_UNASSIGNED) != 0) ? USPREP_ALLOW_UNASSIGNED: 0;
    212     UBool* caseFlags = NULL;
    213 
    214     // the source contains all ascii codepoints
    215     UBool srcIsASCII  = TRUE;
    216     // assume the source contains all LDH codepoints
    217     UBool srcIsLDH = TRUE;
    218 
    219     int32_t j=0;
    220 
    221     //get the options
    222     UBool useSTD3ASCIIRules = (UBool)((options & UIDNA_USE_STD3_RULES) != 0);
    223 
    224     int32_t failPos = -1;
    225 
    226     if(srcLength == -1){
    227         srcLength = u_strlen(src);
    228     }
    229 
    230     if(srcLength > b1Capacity){
    231         b1 = (UChar*) uprv_malloc(srcLength * U_SIZEOF_UCHAR);
    232         if(b1==NULL){
    233             *status = U_MEMORY_ALLOCATION_ERROR;
    234             goto CLEANUP;
    235         }
    236         b1Capacity = srcLength;
    237     }
    238 
    239     // step 1
    240     for( j=0;j<srcLength;j++){
    241         if(src[j] > 0x7F){
    242             srcIsASCII = FALSE;
    243         }
    244         b1[b1Len++] = src[j];
    245     }
    246 
    247     // step 2 is performed only if the source contains non ASCII
    248     if(srcIsASCII == FALSE){
    249 
    250         // step 2
    251         b1Len = usprep_prepare(nameprep, src, srcLength, b1, b1Capacity, namePrepOptions, parseError, status);
    252 
    253         if(*status == U_BUFFER_OVERFLOW_ERROR){
    254             // redo processing of string
    255             // we do not have enough room so grow the buffer
    256             if(b1 != b1Stack){
    257                 uprv_free(b1);
    258             }
    259             b1 = (UChar*) uprv_malloc(b1Len * U_SIZEOF_UCHAR);
    260             if(b1==NULL){
    261                 *status = U_MEMORY_ALLOCATION_ERROR;
    262                 goto CLEANUP;
    263             }
    264 
    265             *status = U_ZERO_ERROR; // reset error
    266 
    267             b1Len = usprep_prepare(nameprep, src, srcLength, b1, b1Len, namePrepOptions, parseError, status);
    268         }
    269     }
    270     // error bail out
    271     if(U_FAILURE(*status)){
    272         goto CLEANUP;
    273     }
    274     if(b1Len == 0){
    275         *status = U_IDNA_ZERO_LENGTH_LABEL_ERROR;
    276         goto CLEANUP;
    277     }
    278 
    279     // for step 3 & 4
    280     srcIsASCII = TRUE;
    281     for( j=0;j<b1Len;j++){
    282         // check if output of usprep_prepare is all ASCII
    283         if(b1[j] > 0x7F){
    284             srcIsASCII = FALSE;
    285         }else if(isLDHChar(b1[j])==FALSE){  // if the char is in ASCII range verify that it is an LDH character
    286             srcIsLDH = FALSE;
    287             failPos = j;
    288         }
    289     }
    290     if(useSTD3ASCIIRules == TRUE){
    291         // verify 3a and 3b
    292         // 3(a) Verify the absence of non-LDH ASCII code points; that is, the
    293         //  absence of 0..2C, 2E..2F, 3A..40, 5B..60, and 7B..7F.
    294         // 3(b) Verify the absence of leading and trailing hyphen-minus; that
    295         //  is, the absence of U+002D at the beginning and end of the
    296         //  sequence.
    297         if( srcIsLDH == FALSE /* source at this point should not contain anyLDH characters */
    298             || b1[0] ==  HYPHEN || b1[b1Len-1] == HYPHEN){
    299             *status = U_IDNA_STD3_ASCII_RULES_ERROR;
    300 
    301             /* populate the parseError struct */
    302             if(srcIsLDH==FALSE){
    303                 // failPos is always set the index of failure
    304                 uprv_syntaxError(b1,failPos, b1Len,parseError);
    305             }else if(b1[0] == HYPHEN){
    306                 // fail position is 0
    307                 uprv_syntaxError(b1,0,b1Len,parseError);
    308             }else{
    309                 // the last index in the source is always length-1
    310                 uprv_syntaxError(b1, (b1Len>0) ? b1Len-1 : b1Len, b1Len,parseError);
    311             }
    312 
    313             goto CLEANUP;
    314         }
    315     }
    316     // Step 4: if the source is ASCII then proceed to step 8
    317     if(srcIsASCII){
    318         if(b1Len <= destCapacity){
    319             uprv_memmove(dest, b1, b1Len * U_SIZEOF_UCHAR);
    320             reqLength = b1Len;
    321         }else{
    322             reqLength = b1Len;
    323             goto CLEANUP;
    324         }
    325     }else{
    326         // step 5 : verify the sequence does not begin with ACE prefix
    327         if(!startsWithPrefix(b1,b1Len)){
    328 
    329             //step 6: encode the sequence with punycode
    330 
    331             // do not preserve the case flags for now!
    332             // TODO: Preserve the case while implementing the RFE
    333             // caseFlags = (UBool*) uprv_malloc(b1Len * sizeof(UBool));
    334             // uprv_memset(caseFlags,TRUE,b1Len);
    335 
    336             b2Len = u_strToPunycode(b1,b1Len,b2,b2Capacity,caseFlags, status);
    337 
    338             if(*status == U_BUFFER_OVERFLOW_ERROR){
    339                 // redo processing of string
    340                 /* we do not have enough room so grow the buffer*/
    341                 b2 = (UChar*) uprv_malloc(b2Len * U_SIZEOF_UCHAR);
    342                 if(b2 == NULL){
    343                     *status = U_MEMORY_ALLOCATION_ERROR;
    344                     goto CLEANUP;
    345                 }
    346 
    347                 *status = U_ZERO_ERROR; // reset error
    348 
    349                 b2Len = u_strToPunycode(b1,b1Len,b2,b2Len,caseFlags, status);
    350             }
    351             //error bail out
    352             if(U_FAILURE(*status)){
    353                 goto CLEANUP;
    354             }
    355             // TODO : Reconsider while implementing the case preserve RFE
    356             // convert all codepoints to lower case ASCII
    357             // toASCIILower(b2,b2Len);
    358             reqLength = b2Len+ACE_PREFIX_LENGTH;
    359 
    360             if(reqLength > destCapacity){
    361                 *status = U_BUFFER_OVERFLOW_ERROR;
    362                 goto CLEANUP;
    363             }
    364             //Step 7: prepend the ACE prefix
    365             uprv_memcpy(dest,ACE_PREFIX,ACE_PREFIX_LENGTH * U_SIZEOF_UCHAR);
    366             //Step 6: copy the contents in b2 into dest
    367             uprv_memcpy(dest+ACE_PREFIX_LENGTH, b2, b2Len * U_SIZEOF_UCHAR);
    368 
    369         }else{
    370             *status = U_IDNA_ACE_PREFIX_ERROR;
    371             //position of failure is 0
    372             uprv_syntaxError(b1,0,b1Len,parseError);
    373             goto CLEANUP;
    374         }
    375     }
    376     // step 8: verify the length of label
    377     if(reqLength > MAX_LABEL_LENGTH){
    378         *status = U_IDNA_LABEL_TOO_LONG_ERROR;
    379     }
    380 
    381 CLEANUP:
    382     if(b1 != b1Stack){
    383         uprv_free(b1);
    384     }
    385     if(b2 != b2Stack){
    386         uprv_free(b2);
    387     }
    388     uprv_free(caseFlags);
    389 
    390     return u_terminateUChars(dest, destCapacity, reqLength, status);
    391 }
    392 
    393 static int32_t
    394 _internal_toUnicode(const UChar* src, int32_t srcLength,
    395                     UChar* dest, int32_t destCapacity,
    396                     int32_t options,
    397                     UStringPrepProfile* nameprep,
    398                     UParseError* parseError,
    399                     UErrorCode* status)
    400 {
    401 
    402     //get the options
    403     //UBool useSTD3ASCIIRules = (UBool)((options & UIDNA_USE_STD3_RULES) != 0);
    404     int32_t namePrepOptions = ((options & UIDNA_ALLOW_UNASSIGNED) != 0) ? USPREP_ALLOW_UNASSIGNED: 0;
    405 
    406     // TODO Revisit buffer handling. The label should not be over 63 ASCII characters. ICU4J may need to be updated too.
    407     UChar b1Stack[MAX_LABEL_BUFFER_SIZE], b2Stack[MAX_LABEL_BUFFER_SIZE], b3Stack[MAX_LABEL_BUFFER_SIZE];
    408 
    409     //initialize pointers to stack buffers
    410     UChar  *b1 = b1Stack, *b2 = b2Stack, *b1Prime=NULL, *b3=b3Stack;
    411     int32_t b1Len = 0, b2Len, b1PrimeLen, b3Len,
    412             b1Capacity = MAX_LABEL_BUFFER_SIZE,
    413             b2Capacity = MAX_LABEL_BUFFER_SIZE,
    414             b3Capacity = MAX_LABEL_BUFFER_SIZE,
    415             reqLength=0;
    416 
    417     UBool* caseFlags = NULL;
    418 
    419     UBool srcIsASCII = TRUE;
    420     /*UBool srcIsLDH = TRUE;
    421     int32_t failPos =0;*/
    422 
    423     // step 1: find out if all the codepoints in src are ASCII
    424     if(srcLength==-1){
    425         srcLength = 0;
    426         for(;src[srcLength]!=0;){
    427             if(src[srcLength]> 0x7f){
    428                 srcIsASCII = FALSE;
    429             }/*else if(isLDHChar(src[srcLength])==FALSE){
    430                 // here we do not assemble surrogates
    431                 // since we know that LDH code points
    432                 // are in the ASCII range only
    433                 srcIsLDH = FALSE;
    434                 failPos = srcLength;
    435             }*/
    436             srcLength++;
    437         }
    438     }else if(srcLength > 0){
    439         for(int32_t j=0; j<srcLength; j++){
    440             if(src[j]> 0x7f){
    441                 srcIsASCII = FALSE;
    442             }/*else if(isLDHChar(src[j])==FALSE){
    443                 // here we do not assemble surrogates
    444                 // since we know that LDH code points
    445                 // are in the ASCII range only
    446                 srcIsLDH = FALSE;
    447                 failPos = j;
    448             }*/
    449         }
    450     }else{
    451         return 0;
    452     }
    453 
    454     if(srcIsASCII == FALSE){
    455         // step 2: process the string
    456         b1Len = usprep_prepare(nameprep, src, srcLength, b1, b1Capacity, namePrepOptions, parseError, status);
    457         if(*status == U_BUFFER_OVERFLOW_ERROR){
    458             // redo processing of string
    459             /* we do not have enough room so grow the buffer*/
    460             b1 = (UChar*) uprv_malloc(b1Len * U_SIZEOF_UCHAR);
    461             if(b1==NULL){
    462                 *status = U_MEMORY_ALLOCATION_ERROR;
    463                 goto CLEANUP;
    464             }
    465 
    466             *status = U_ZERO_ERROR; // reset error
    467 
    468             b1Len = usprep_prepare(nameprep, src, srcLength, b1, b1Len, namePrepOptions, parseError, status);
    469         }
    470         //bail out on error
    471         if(U_FAILURE(*status)){
    472             goto CLEANUP;
    473         }
    474     }else{
    475 
    476         //just point src to b1
    477         b1 = (UChar*) src;
    478         b1Len = srcLength;
    479     }
    480 
    481     // The RFC states that
    482     // <quote>
    483     // ToUnicode never fails. If any step fails, then the original input
    484     // is returned immediately in that step.
    485     // </quote>
    486 
    487     //step 3: verify ACE Prefix
    488     if(startsWithPrefix(b1,b1Len)){
    489 
    490         //step 4: Remove the ACE Prefix
    491         b1Prime = b1 + ACE_PREFIX_LENGTH;
    492         b1PrimeLen  = b1Len - ACE_PREFIX_LENGTH;
    493 
    494         //step 5: Decode using punycode
    495         b2Len = u_strFromPunycode(b1Prime, b1PrimeLen, b2, b2Capacity, caseFlags,status);
    496 
    497         if(*status == U_BUFFER_OVERFLOW_ERROR){
    498             // redo processing of string
    499             /* we do not have enough room so grow the buffer*/
    500             b2 = (UChar*) uprv_malloc(b2Len * U_SIZEOF_UCHAR);
    501             if(b2==NULL){
    502                 *status = U_MEMORY_ALLOCATION_ERROR;
    503                 goto CLEANUP;
    504             }
    505 
    506             *status = U_ZERO_ERROR; // reset error
    507 
    508             b2Len =  u_strFromPunycode(b1Prime, b1PrimeLen, b2, b2Len, caseFlags, status);
    509         }
    510 
    511 
    512         //step 6:Apply toASCII
    513         b3Len = uidna_toASCII(b2, b2Len, b3, b3Capacity, options, parseError, status);
    514 
    515         if(*status == U_BUFFER_OVERFLOW_ERROR){
    516             // redo processing of string
    517             /* we do not have enough room so grow the buffer*/
    518             b3 = (UChar*) uprv_malloc(b3Len * U_SIZEOF_UCHAR);
    519             if(b3==NULL){
    520                 *status = U_MEMORY_ALLOCATION_ERROR;
    521                 goto CLEANUP;
    522             }
    523 
    524             *status = U_ZERO_ERROR; // reset error
    525 
    526             b3Len =  uidna_toASCII(b2,b2Len,b3,b3Len,options,parseError, status);
    527 
    528         }
    529         //bail out on error
    530         if(U_FAILURE(*status)){
    531             goto CLEANUP;
    532         }
    533 
    534         //step 7: verify
    535         if(compareCaseInsensitiveASCII(b1, b1Len, b3, b3Len) !=0){
    536             // Cause the original to be returned.
    537             *status = U_IDNA_VERIFICATION_ERROR;
    538             goto CLEANUP;
    539         }
    540 
    541         //step 8: return output of step 5
    542         reqLength = b2Len;
    543         if(b2Len <= destCapacity) {
    544             uprv_memmove(dest, b2, b2Len * U_SIZEOF_UCHAR);
    545         }
    546     }
    547     else{
    548         // See the start of this if statement for why this is commented out.
    549         // verify that STD3 ASCII rules are satisfied
    550         /*if(useSTD3ASCIIRules == TRUE){
    551             if( srcIsLDH == FALSE // source contains some non-LDH characters
    552                 || src[0] ==  HYPHEN || src[srcLength-1] == HYPHEN){
    553                 *status = U_IDNA_STD3_ASCII_RULES_ERROR;
    554 
    555                 // populate the parseError struct
    556                 if(srcIsLDH==FALSE){
    557                     // failPos is always set the index of failure
    558                     uprv_syntaxError(src,failPos, srcLength,parseError);
    559                 }else if(src[0] == HYPHEN){
    560                     // fail position is 0
    561                     uprv_syntaxError(src,0,srcLength,parseError);
    562                 }else{
    563                     // the last index in the source is always length-1
    564                     uprv_syntaxError(src, (srcLength>0) ? srcLength-1 : srcLength, srcLength,parseError);
    565                 }
    566 
    567                 goto CLEANUP;
    568             }
    569         }*/
    570         // just return the source
    571         //copy the source to destination
    572         if(srcLength <= destCapacity){
    573             uprv_memmove(dest,src,srcLength * U_SIZEOF_UCHAR);
    574         }
    575         reqLength = srcLength;
    576     }
    577 
    578 
    579 CLEANUP:
    580 
    581     if(b1 != b1Stack && b1!=src){
    582         uprv_free(b1);
    583     }
    584     if(b2 != b2Stack){
    585         uprv_free(b2);
    586     }
    587     uprv_free(caseFlags);
    588 
    589     // The RFC states that
    590     // <quote>
    591     // ToUnicode never fails. If any step fails, then the original input
    592     // is returned immediately in that step.
    593     // </quote>
    594     // So if any step fails lets copy source to destination
    595     if(U_FAILURE(*status)){
    596         //copy the source to destination
    597         if(dest && srcLength <= destCapacity){
    598             // srcLength should have already been set earlier.
    599             U_ASSERT(srcLength >= 0);
    600             uprv_memmove(dest,src,srcLength * U_SIZEOF_UCHAR);
    601         }
    602         reqLength = srcLength;
    603         *status = U_ZERO_ERROR;
    604     }
    605 
    606     return u_terminateUChars(dest, destCapacity, reqLength, status);
    607 }
    608 
    609 U_CAPI int32_t U_EXPORT2
    610 uidna_toASCII(const UChar* src, int32_t srcLength,
    611               UChar* dest, int32_t destCapacity,
    612               int32_t options,
    613               UParseError* parseError,
    614               UErrorCode* status){
    615 
    616     if(status == NULL || U_FAILURE(*status)){
    617         return 0;
    618     }
    619     if((src==NULL) || (srcLength < -1) || (destCapacity<0) || (!dest && destCapacity > 0)){
    620         *status = U_ILLEGAL_ARGUMENT_ERROR;
    621         return 0;
    622     }
    623 
    624     UStringPrepProfile* nameprep = usprep_openByType(USPREP_RFC3491_NAMEPREP, status);
    625 
    626     if(U_FAILURE(*status)){
    627         return -1;
    628     }
    629 
    630     int32_t retLen = _internal_toASCII(src, srcLength, dest, destCapacity, options, nameprep, parseError, status);
    631 
    632     /* close the profile*/
    633     usprep_close(nameprep);
    634 
    635     return retLen;
    636 }
    637 
    638 U_CAPI int32_t U_EXPORT2
    639 uidna_toUnicode(const UChar* src, int32_t srcLength,
    640                 UChar* dest, int32_t destCapacity,
    641                 int32_t options,
    642                 UParseError* parseError,
    643                 UErrorCode* status){
    644 
    645     if(status == NULL || U_FAILURE(*status)){
    646         return 0;
    647     }
    648     if( (src==NULL) || (srcLength < -1) || (destCapacity<0) || (!dest && destCapacity > 0)){
    649         *status = U_ILLEGAL_ARGUMENT_ERROR;
    650         return 0;
    651     }
    652 
    653     UStringPrepProfile* nameprep = usprep_openByType(USPREP_RFC3491_NAMEPREP, status);
    654 
    655     if(U_FAILURE(*status)){
    656         return -1;
    657     }
    658 
    659     int32_t retLen = _internal_toUnicode(src, srcLength, dest, destCapacity, options, nameprep, parseError, status);
    660 
    661     usprep_close(nameprep);
    662 
    663     return retLen;
    664 }
    665 
    666 
    667 U_CAPI int32_t U_EXPORT2
    668 uidna_IDNToASCII(  const UChar *src, int32_t srcLength,
    669                    UChar* dest, int32_t destCapacity,
    670                    int32_t options,
    671                    UParseError *parseError,
    672                    UErrorCode *status){
    673 
    674     if(status == NULL || U_FAILURE(*status)){
    675         return 0;
    676     }
    677     if((src==NULL) || (srcLength < -1) || (destCapacity<0) || (!dest && destCapacity > 0)){
    678         *status = U_ILLEGAL_ARGUMENT_ERROR;
    679         return 0;
    680     }
    681 
    682     int32_t reqLength = 0;
    683 
    684     UStringPrepProfile* nameprep = usprep_openByType(USPREP_RFC3491_NAMEPREP, status);
    685 
    686     if(U_FAILURE(*status)){
    687         return 0;
    688     }
    689 
    690     //initialize pointers
    691     UChar *delimiter = (UChar*)src;
    692     UChar *labelStart = (UChar*)src;
    693     UChar *currentDest = (UChar*) dest;
    694     int32_t remainingLen = srcLength;
    695     int32_t remainingDestCapacity = destCapacity;
    696     int32_t labelLen = 0, labelReqLength = 0;
    697     UBool done = FALSE;
    698 
    699 
    700     for(;;){
    701 
    702         labelLen = getNextSeparator(labelStart,remainingLen, &delimiter,&done);
    703         labelReqLength = 0;
    704         if(!(labelLen==0 && done)){// make sure this is not a root label separator.
    705 
    706             labelReqLength = _internal_toASCII( labelStart, labelLen,
    707                                                 currentDest, remainingDestCapacity,
    708                                                 options, nameprep,
    709                                                 parseError, status);
    710 
    711             if(*status == U_BUFFER_OVERFLOW_ERROR){
    712 
    713                 *status = U_ZERO_ERROR; // reset error
    714                 remainingDestCapacity = 0;
    715             }
    716         }
    717 
    718 
    719         if(U_FAILURE(*status)){
    720             break;
    721         }
    722 
    723         reqLength +=labelReqLength;
    724         // adjust the destination pointer
    725         if(labelReqLength < remainingDestCapacity){
    726             currentDest = currentDest + labelReqLength;
    727             remainingDestCapacity -= labelReqLength;
    728         }else{
    729             // should never occur
    730             remainingDestCapacity = 0;
    731         }
    732 
    733         if(done == TRUE){
    734             break;
    735         }
    736 
    737         // add the label separator
    738         if(remainingDestCapacity > 0){
    739             *currentDest++ = FULL_STOP;
    740             remainingDestCapacity--;
    741         }
    742         reqLength++;
    743 
    744         labelStart = delimiter;
    745         if(remainingLen >0 ){
    746             remainingLen = (int32_t)(srcLength - (delimiter - src));
    747         }
    748 
    749     }
    750 
    751     if(reqLength > MAX_DOMAIN_NAME_LENGTH){
    752         *status = U_IDNA_DOMAIN_NAME_TOO_LONG_ERROR;
    753     }
    754 
    755     usprep_close(nameprep);
    756 
    757     return u_terminateUChars(dest, destCapacity, reqLength, status);
    758 }
    759 
    760 U_CAPI int32_t U_EXPORT2
    761 uidna_IDNToUnicode(  const UChar* src, int32_t srcLength,
    762                      UChar* dest, int32_t destCapacity,
    763                      int32_t options,
    764                      UParseError* parseError,
    765                      UErrorCode* status){
    766 
    767     if(status == NULL || U_FAILURE(*status)){
    768         return 0;
    769     }
    770     if((src==NULL) || (srcLength < -1) || (destCapacity<0) || (!dest && destCapacity > 0)){
    771         *status = U_ILLEGAL_ARGUMENT_ERROR;
    772         return 0;
    773     }
    774 
    775     int32_t reqLength = 0;
    776 
    777     UStringPrepProfile* nameprep = usprep_openByType(USPREP_RFC3491_NAMEPREP, status);
    778 
    779     if(U_FAILURE(*status)){
    780         return 0;
    781     }
    782 
    783     //initialize pointers
    784     UChar *delimiter = (UChar*)src;
    785     UChar *labelStart = (UChar*)src;
    786     UChar *currentDest = (UChar*) dest;
    787     int32_t remainingLen = srcLength;
    788     int32_t remainingDestCapacity = destCapacity;
    789     int32_t labelLen = 0, labelReqLength = 0;
    790     UBool done = FALSE;
    791 
    792     for(;;){
    793 
    794         labelLen = getNextSeparator(labelStart,remainingLen, &delimiter,&done);
    795 
    796         // The RFC states that
    797         // <quote>
    798         // ToUnicode never fails. If any step fails, then the original input
    799         // is returned immediately in that step.
    800         // </quote>
    801         // _internal_toUnicode will copy the label.
    802         /*if(labelLen==0 && done==FALSE){
    803             *status = U_IDNA_ZERO_LENGTH_LABEL_ERROR;
    804             break;
    805         }*/
    806 
    807         labelReqLength = _internal_toUnicode(labelStart, labelLen,
    808                                              currentDest, remainingDestCapacity,
    809                                              options, nameprep,
    810                                              parseError, status);
    811 
    812         if(*status == U_BUFFER_OVERFLOW_ERROR){
    813             *status = U_ZERO_ERROR; // reset error
    814             remainingDestCapacity = 0;
    815         }
    816 
    817         if(U_FAILURE(*status)){
    818             break;
    819         }
    820 
    821         reqLength +=labelReqLength;
    822         // adjust the destination pointer
    823         if(labelReqLength < remainingDestCapacity){
    824             currentDest = currentDest + labelReqLength;
    825             remainingDestCapacity -= labelReqLength;
    826         }else{
    827             // should never occur
    828             remainingDestCapacity = 0;
    829         }
    830 
    831         if(done == TRUE){
    832             break;
    833         }
    834 
    835         // add the label separator
    836         // Unlike the ToASCII operation we don't normalize the label separators
    837         if(remainingDestCapacity > 0){
    838             *currentDest++ = *(labelStart + labelLen);
    839             remainingDestCapacity--;
    840         }
    841         reqLength++;
    842 
    843         labelStart = delimiter;
    844         if(remainingLen >0 ){
    845             remainingLen = (int32_t)(srcLength - (delimiter - src));
    846         }
    847 
    848     }
    849 
    850     if(reqLength > MAX_DOMAIN_NAME_LENGTH){
    851         *status = U_IDNA_DOMAIN_NAME_TOO_LONG_ERROR;
    852     }
    853 
    854     usprep_close(nameprep);
    855 
    856     return u_terminateUChars(dest, destCapacity, reqLength, status);
    857 }
    858 
    859 U_CAPI int32_t U_EXPORT2
    860 uidna_compare(  const UChar *s1, int32_t length1,
    861                 const UChar *s2, int32_t length2,
    862                 int32_t options,
    863                 UErrorCode* status){
    864 
    865     if(status == NULL || U_FAILURE(*status)){
    866         return -1;
    867     }
    868 
    869     UChar b1Stack[MAX_IDN_BUFFER_SIZE], b2Stack[MAX_IDN_BUFFER_SIZE];
    870     UChar *b1 = b1Stack, *b2 = b2Stack;
    871     int32_t b1Len, b2Len, b1Capacity = MAX_IDN_BUFFER_SIZE, b2Capacity = MAX_IDN_BUFFER_SIZE;
    872     int32_t result=-1;
    873 
    874     UParseError parseError;
    875 
    876     b1Len = uidna_IDNToASCII(s1, length1, b1, b1Capacity, options, &parseError, status);
    877     if(*status == U_BUFFER_OVERFLOW_ERROR){
    878         // redo processing of string
    879         b1 = (UChar*) uprv_malloc(b1Len * U_SIZEOF_UCHAR);
    880         if(b1==NULL){
    881             *status = U_MEMORY_ALLOCATION_ERROR;
    882             goto CLEANUP;
    883         }
    884 
    885         *status = U_ZERO_ERROR; // reset error
    886 
    887         b1Len = uidna_IDNToASCII(s1,length1,b1,b1Len, options, &parseError, status);
    888 
    889     }
    890 
    891     b2Len = uidna_IDNToASCII(s2,length2, b2,b2Capacity, options, &parseError, status);
    892     if(*status == U_BUFFER_OVERFLOW_ERROR){
    893         // redo processing of string
    894         b2 = (UChar*) uprv_malloc(b2Len * U_SIZEOF_UCHAR);
    895         if(b2==NULL){
    896             *status = U_MEMORY_ALLOCATION_ERROR;
    897             goto CLEANUP;
    898         }
    899 
    900         *status = U_ZERO_ERROR; // reset error
    901 
    902         b2Len = uidna_IDNToASCII(s2, length2, b2, b2Len, options, &parseError, status);
    903 
    904     }
    905     // when toASCII is applied all label separators are replaced with FULL_STOP
    906     result = compareCaseInsensitiveASCII(b1,b1Len,b2,b2Len);
    907 
    908 CLEANUP:
    909     if(b1 != b1Stack){
    910         uprv_free(b1);
    911     }
    912 
    913     if(b2 != b2Stack){
    914         uprv_free(b2);
    915     }
    916 
    917     return result;
    918 }
    919 
    920 #endif /* #if !UCONFIG_NO_IDNA */
    921