// © 2016 and later: Unicode, Inc. and others.

// License & terms of use: http://www.unicode.org/copyright.html

/*

 *******************************************************************************

 *

 *   Copyright (C) 2003-2016, International Business Machines

 *   Corporation and others.  All Rights Reserved.

 *

 *******************************************************************************

 *   file name:  usprep.cpp

 *   encoding:   UTF-8

 *   tab size:   8 (not used)

 *   indentation:4

 *

 *   created on: 2003jul2

 *   created by: Ram Viswanadha

 */

#include "unicode/utypes.h"

#if !UCONFIG_NO_IDNA

#include "unicode/usprep.h"

#include "unicode/normalizer2.h"

#include "unicode/ustring.h"

#include "unicode/uchar.h"

#include "unicode/uversion.h"

#include "umutex.h"

#include "cmemory.h"

#include "sprpimpl.h"

#include "ustr_imp.h"

#include "uhash.h"

#include "cstring.h"

#include "udataswp.h"

#include "ucln_cmn.h"

#include "ubidi_props.h"

#include "uprops.h"

U_NAMESPACE_USE

U_CDECL_BEGIN

/*

Static cache for already opened StringPrep profiles

*/

static UHashtable *SHARED_DATA_HASHTABLE = NULL;

static icu::UInitOnce gSharedDataInitOnce;

static UMutex usprepMutex = U_MUTEX_INITIALIZER;

/* format version of spp file */

//static uint8_t formatVersion[4]={ 0, 0, 0, 0 };

/* the Unicode version of the sprep data */

static UVersionInfo dataVersion={ 0, 0, 0, 0 };

/* Profile names must be aligned to UStringPrepProfileType */

static const char * const PROFILE_NAMES[] = {

    "rfc3491",      /* USPREP_RFC3491_NAMEPREP */

    "rfc3530cs",    /* USPREP_RFC3530_NFS4_CS_PREP */

    "rfc3530csci",  /* USPREP_RFC3530_NFS4_CS_PREP_CI */

    "rfc3491",      /* USPREP_RFC3530_NSF4_CIS_PREP */

    "rfc3530mixp",  /* USPREP_RFC3530_NSF4_MIXED_PREP_PREFIX */

    "rfc3491",      /* USPREP_RFC3530_NSF4_MIXED_PREP_SUFFIX */

    "rfc3722",      /* USPREP_RFC3722_ISCSI */

    "rfc3920node",  /* USPREP_RFC3920_NODEPREP */

    "rfc3920res",   /* USPREP_RFC3920_RESOURCEPREP */

    "rfc4011",      /* USPREP_RFC4011_MIB */

    "rfc4013",      /* USPREP_RFC4013_SASLPREP */

    "rfc4505",      /* USPREP_RFC4505_TRACE */

    "rfc4518",      /* USPREP_RFC4518_LDAP */

    "rfc4518ci",    /* USPREP_RFC4518_LDAP_CI */

};

static UBool U_CALLCONV

isSPrepAcceptable(void * /* context */,

             const char * /* type */, 

             const char * /* name */,

             const UDataInfo *pInfo) {

    if(

        pInfo->size>=20 &&

        pInfo->isBigEndian==U_IS_BIG_ENDIAN &&

        pInfo->charsetFamily==U_CHARSET_FAMILY &&

        pInfo->dataFormat[0]==0x53 &&   /* dataFormat="SPRP" */

        pInfo->dataFormat[1]==0x50 &&

        pInfo->dataFormat[2]==0x52 &&

        pInfo->dataFormat[3]==0x50 &&

        pInfo->formatVersion[0]==3 &&

        pInfo->formatVersion[2]==UTRIE_SHIFT &&

        pInfo->formatVersion[3]==UTRIE_INDEX_SHIFT

    ) {

        //uprv_memcpy(formatVersion, pInfo->formatVersion, 4);

        uprv_memcpy(dataVersion, pInfo->dataVersion, 4);

        return TRUE;

    } else {

        return FALSE;

    }

}

static int32_t U_CALLCONV

getSPrepFoldingOffset(uint32_t data) {

    return (int32_t)data;

}

/* hashes an entry  */

static int32_t U_CALLCONV 

hashEntry(const UHashTok parm) {

    UStringPrepKey *b = (UStringPrepKey *)parm.pointer;

    UHashTok namekey, pathkey;

    namekey.pointer = b->name;

    pathkey.pointer = b->path;

    return uhash_hashChars(namekey)+37*uhash_hashChars(pathkey);

}

/* compares two entries */

static UBool U_CALLCONV 

compareEntries(const UHashTok p1, const UHashTok p2) {

    UStringPrepKey *b1 = (UStringPrepKey *)p1.pointer;

    UStringPrepKey *b2 = (UStringPrepKey *)p2.pointer;

    UHashTok name1, name2, path1, path2;

    name1.pointer = b1->name;

    name2.pointer = b2->name;

    path1.pointer = b1->path;

    path2.pointer = b2->path;

    return ((UBool)(uhash_compareChars(name1, name2) & 

        uhash_compareChars(path1, path2)));

}

static void 

usprep_unload(UStringPrepProfile* data){

    udata_close(data->sprepData);

}

static int32_t 

usprep_internal_flushCache(UBool noRefCount){

    UStringPrepProfile *profile = NULL;

    UStringPrepKey  *key  = NULL;

    int32_t pos = UHASH_FIRST;

    int32_t deletedNum = 0;

    const UHashElement *e;

    /*

     * if shared data hasn't even been lazy evaluated yet

     * return 0

     */

    umtx_lock(&usprepMutex);

    if (SHARED_DATA_HASHTABLE == NULL) {

        umtx_unlock(&usprepMutex);

        return 0;

    }

    /*creates an enumeration to iterate through every element in the table */

    while ((e = uhash_nextElement(SHARED_DATA_HASHTABLE, &pos)) != NULL)

    {

        profile = (UStringPrepProfile *) e->value.pointer;

        key  = (UStringPrepKey *) e->key.pointer;

        if ((noRefCount== FALSE && profile->refCount == 0) || 

             noRefCount== TRUE) {

            deletedNum++;

            uhash_removeElement(SHARED_DATA_HASHTABLE, e);

            /* unload the data */

            usprep_unload(profile);

            if(key->name != NULL) {

                uprv_free(key->name);

                key->name=NULL;

            }

            if(key->path != NULL) {

                uprv_free(key->path);

                key->path=NULL;

            }

            uprv_free(profile);

            uprv_free(key);

        }

    }

    umtx_unlock(&usprepMutex);

    return deletedNum;

}

/* Works just like ucnv_flushCache() 

static int32_t 

usprep_flushCache(){

    return usprep_internal_flushCache(FALSE);

}

*/

static UBool U_CALLCONV usprep_cleanup(void){

    if (SHARED_DATA_HASHTABLE != NULL) {

        usprep_internal_flushCache(TRUE);

        if (SHARED_DATA_HASHTABLE != NULL && uhash_count(SHARED_DATA_HASHTABLE) == 0) {

            uhash_close(SHARED_DATA_HASHTABLE);

            SHARED_DATA_HASHTABLE = NULL;

        }

    }

    gSharedDataInitOnce.reset();

    return (SHARED_DATA_HASHTABLE == NULL);

}

U_CDECL_END

/** Initializes the cache for resources */

static void U_CALLCONV

createCache(UErrorCode &status) {

    SHARED_DATA_HASHTABLE = uhash_open(hashEntry, compareEntries, NULL, &status);

    if (U_FAILURE(status)) {

        SHARED_DATA_HASHTABLE = NULL;

    }

    ucln_common_registerCleanup(UCLN_COMMON_USPREP, usprep_cleanup);

}

static void 

initCache(UErrorCode *status) {

    umtx_initOnce(gSharedDataInitOnce, &createCache, *status);

}

static UBool U_CALLCONV

loadData(UStringPrepProfile* profile, 

         const char* path, 

         const char* name, 

         const char* type, 

         UErrorCode* errorCode) {

    /* load Unicode SPREP data from file */    

    UTrie _sprepTrie={ 0,0,0,0,0,0,0 };

    UDataMemory *dataMemory;

    const int32_t *p=NULL;

    const uint8_t *pb;

    UVersionInfo normUnicodeVersion;

    int32_t normUniVer, sprepUniVer, normCorrVer;

    if(errorCode==NULL || U_FAILURE(*errorCode)) {

        return 0;

    }

    /* open the data outside the mutex block */

    //TODO: change the path

    dataMemory=udata_openChoice(path, type, name, isSPrepAcceptable, NULL, errorCode);

    if(U_FAILURE(*errorCode)) {

        return FALSE;

    }

    p=(const int32_t *)udata_getMemory(dataMemory);

    pb=(const uint8_t *)(p+_SPREP_INDEX_TOP);

    utrie_unserialize(&_sprepTrie, pb, p[_SPREP_INDEX_TRIE_SIZE], errorCode);

    _sprepTrie.getFoldingOffset=getSPrepFoldingOffset;

    if(U_FAILURE(*errorCode)) {

        udata_close(dataMemory);

        return FALSE;

    }

    /* in the mutex block, set the data for this process */

    umtx_lock(&usprepMutex);

    if(profile->sprepData==NULL) {

        profile->sprepData=dataMemory;

        dataMemory=NULL;

        uprv_memcpy(&profile->indexes, p, sizeof(profile->indexes));

        uprv_memcpy(&profile->sprepTrie, &_sprepTrie, sizeof(UTrie));

    } else {

        p=(const int32_t *)udata_getMemory(profile->sprepData);

    }

    umtx_unlock(&usprepMutex);

    /* initialize some variables */

    profile->mappingData=(uint16_t *)((uint8_t *)(p+_SPREP_INDEX_TOP)+profile->indexes[_SPREP_INDEX_TRIE_SIZE]);

    u_getUnicodeVersion(normUnicodeVersion);

    normUniVer = (normUnicodeVersion[0] << 24) + (normUnicodeVersion[1] << 16) + 

                 (normUnicodeVersion[2] << 8 ) + (normUnicodeVersion[3]);

    sprepUniVer = (dataVersion[0] << 24) + (dataVersion[1] << 16) + 

                  (dataVersion[2] << 8 ) + (dataVersion[3]);

    normCorrVer = profile->indexes[_SPREP_NORM_CORRECTNS_LAST_UNI_VERSION];

    if(U_FAILURE(*errorCode)){

        udata_close(dataMemory);

        return FALSE;

    }

    if( normUniVer < sprepUniVer && /* the Unicode version of SPREP file must be less than the Unicode Vesion of the normalization data */

        normUniVer < normCorrVer && /* the Unicode version of the NormalizationCorrections.txt file should be less than the Unicode Vesion of the normalization data */

        ((profile->indexes[_SPREP_OPTIONS] & _SPREP_NORMALIZATION_ON) > 0) /* normalization turned on*/

      ){

        *errorCode = U_INVALID_FORMAT_ERROR;

        udata_close(dataMemory);

        return FALSE;

    }

    profile->isDataLoaded = TRUE;

    /* if a different thread set it first, then close the extra data */

    if(dataMemory!=NULL) {

        udata_close(dataMemory); /* NULL if it was set correctly */

    }

    return profile->isDataLoaded;

}

static UStringPrepProfile* 

usprep_getProfile(const char* path, 

                  const char* name,

                  UErrorCode *status){

    UStringPrepProfile* profile = NULL;

    initCache(status);

    if(U_FAILURE(*status)){

        return NULL;

    }

    UStringPrepKey stackKey;

    /* 

     * const is cast way to save malloc, strcpy and free calls 

     * we use the passed in pointers for fetching the data from the 

     * hash table which is safe

     */

    stackKey.name = (char*) name;

    stackKey.path = (char*) path;

    /* fetch the data from the cache */

    umtx_lock(&usprepMutex);

    profile = (UStringPrepProfile*) (uhash_get(SHARED_DATA_HASHTABLE,&stackKey));

    if(profile != NULL) {

        profile->refCount++;

    }

    umtx_unlock(&usprepMutex);

    if(profile == NULL) {

        /* else load the data and put the data in the cache */

        LocalMemory<UStringPrepProfile> newProfile;

        if(newProfile.allocateInsteadAndReset() == NULL) {

            *status = U_MEMORY_ALLOCATION_ERROR;

            return NULL;

        }

        /* load the data */

        if(!loadData(newProfile.getAlias(), path, name, _SPREP_DATA_TYPE, status) || U_FAILURE(*status) ){

            return NULL;

        }

        /* get the options */

        newProfile->doNFKC = (UBool)((newProfile->indexes[_SPREP_OPTIONS] & _SPREP_NORMALIZATION_ON) > 0);

        newProfile->checkBiDi = (UBool)((newProfile->indexes[_SPREP_OPTIONS] & _SPREP_CHECK_BIDI_ON) > 0);

        LocalMemory<UStringPrepKey> key;

        LocalMemory<char> keyName;

        LocalMemory<char> keyPath;

        if( key.allocateInsteadAndReset() == NULL ||

            keyName.allocateInsteadAndCopy(uprv_strlen(name)+1) == NULL ||

            (path != NULL &&

             keyPath.allocateInsteadAndCopy(uprv_strlen(path)+1) == NULL)

         ) {

            *status = U_MEMORY_ALLOCATION_ERROR;

            usprep_unload(newProfile.getAlias());

            return NULL;

        }

        umtx_lock(&usprepMutex);

        // If another thread already inserted the same key/value, refcount and cleanup our thread data

        profile = (UStringPrepProfile*) (uhash_get(SHARED_DATA_HASHTABLE,&stackKey));

        if(profile != NULL) {

            profile->refCount++;

            usprep_unload(newProfile.getAlias());

        }

        else {

            /* initialize the key members */

            key->name = keyName.orphan();

            uprv_strcpy(key->name, name);

            if(path != NULL){

                key->path = keyPath.orphan();

                uprv_strcpy(key->path, path);

            }        

            profile = newProfile.orphan();

            /* add the data object to the cache */

            profile->refCount = 1;

            uhash_put(SHARED_DATA_HASHTABLE, key.orphan(), profile, status);

        }

        umtx_unlock(&usprepMutex);

    }

    return profile;

}

U_CAPI UStringPrepProfile* U_EXPORT2

usprep_open(const char* path, 

            const char* name,

            UErrorCode* status){

    if(status == NULL || U_FAILURE(*status)){

        return NULL;

    }

    /* initialize the profile struct members */

    return usprep_getProfile(path,name,status);

}

U_CAPI UStringPrepProfile* U_EXPORT2

usprep_openByType(UStringPrepProfileType type,

          UErrorCode* status) {

    if(status == NULL || U_FAILURE(*status)){

        return NULL;

    }

    int32_t index = (int32_t)type;

    if (index < 0 || index >= UPRV_LENGTHOF(PROFILE_NAMES)) {

        *status = U_ILLEGAL_ARGUMENT_ERROR;

        return NULL;

    }

    return usprep_open(NULL, PROFILE_NAMES[index], status);

}

U_CAPI void U_EXPORT2

usprep_close(UStringPrepProfile* profile){

    if(profile==NULL){

        return;

    }

    umtx_lock(&usprepMutex);

    /* decrement the ref count*/

    if(profile->refCount > 0){

        profile->refCount--;

    }

    umtx_unlock(&usprepMutex);

}

U_CFUNC void 

uprv_syntaxError(const UChar* rules, 

                 int32_t pos,

                 int32_t rulesLen,

                 UParseError* parseError){

    if(parseError == NULL){

        return;

    }

    parseError->offset = pos;

    parseError->line = 0 ; // we are not using line numbers 

    // for pre-context

    int32_t start = (pos < U_PARSE_CONTEXT_LEN)? 0 : (pos - (U_PARSE_CONTEXT_LEN-1));

    int32_t limit = pos;

    u_memcpy(parseError->preContext,rules+start,limit-start);

    //null terminate the buffer

    parseError->preContext[limit-start] = 0;

    // for post-context; include error rules[pos]

    start = pos;

    limit = start + (U_PARSE_CONTEXT_LEN-1);

    if (limit > rulesLen) {

        limit = rulesLen;

    }

    if (start < rulesLen) {

        u_memcpy(parseError->postContext,rules+start,limit-start);

    }

    //null terminate the buffer

    parseError->postContext[limit-start]= 0;

}

static inline UStringPrepType

getValues(uint16_t trieWord, int16_t& value, UBool& isIndex){

    UStringPrepType type;

    if(trieWord == 0){

        /* 

         * Initial value stored in the mapping table 

         * just return USPREP_TYPE_LIMIT .. so that

         * the source codepoint is copied to the destination

         */

        type = USPREP_TYPE_LIMIT;

        isIndex =FALSE;

        value = 0;

    }else if(trieWord >= _SPREP_TYPE_THRESHOLD){

        type = (UStringPrepType) (trieWord - _SPREP_TYPE_THRESHOLD);

        isIndex =FALSE;

        value = 0;

    }else{

        /* get the type */

        type = USPREP_MAP;

        /* ascertain if the value is index or delta */

        if(trieWord & 0x02){

            isIndex = TRUE;

            value = trieWord  >> 2; //mask off the lower 2 bits and shift

        }else{

            isIndex = FALSE;

            value = (int16_t)trieWord;

            value =  (value >> 2);

        }

        if((trieWord>>2) == _SPREP_MAX_INDEX_VALUE){

            type = USPREP_DELETE;

            isIndex =FALSE;

            value = 0;

        }

    }

    return type;

}

// TODO: change to writing to UnicodeString not UChar *

static int32_t 

usprep_map(  const UStringPrepProfile* profile, 

             const UChar* src, int32_t srcLength, 

             UChar* dest, int32_t destCapacity,

             int32_t options,

             UParseError* parseError,

             UErrorCode* status ){

    uint16_t result;

    int32_t destIndex=0;

    int32_t srcIndex;

    UBool allowUnassigned = (UBool) ((options & USPREP_ALLOW_UNASSIGNED)>0);

    UStringPrepType type;

    int16_t value;

    UBool isIndex;

    const int32_t* indexes = profile->indexes;

    // no error checking the caller check for error and arguments

    // no string length check the caller finds out the string length

    for(srcIndex=0;srcIndex<srcLength;){

        UChar32 ch;

        U16_NEXT(src,srcIndex,srcLength,ch);

        result=0;

        UTRIE_GET16(&profile->sprepTrie,ch,result);

        type = getValues(result, value, isIndex);

        // check if the source codepoint is unassigned

        if(type == USPREP_UNASSIGNED && allowUnassigned == FALSE){

            uprv_syntaxError(src,srcIndex-U16_LENGTH(ch), srcLength,parseError);

            *status = U_STRINGPREP_UNASSIGNED_ERROR;

            return 0;

        }else if(type == USPREP_MAP){

            int32_t index, length;

            if(isIndex){

                index = value;

                if(index >= indexes[_SPREP_ONE_UCHAR_MAPPING_INDEX_START] &&

                         index < indexes[_SPREP_TWO_UCHARS_MAPPING_INDEX_START]){

                    length = 1;

                }else if(index >= indexes[_SPREP_TWO_UCHARS_MAPPING_INDEX_START] &&

                         index < indexes[_SPREP_THREE_UCHARS_MAPPING_INDEX_START]){

                    length = 2;

                }else if(index >= indexes[_SPREP_THREE_UCHARS_MAPPING_INDEX_START] &&

                         index < indexes[_SPREP_FOUR_UCHARS_MAPPING_INDEX_START]){

                    length = 3;

                }else{

                    length = profile->mappingData[index++];

                }

                /* copy mapping to destination */

                for(int32_t i=0; i< length; i++){

                    if(destIndex < destCapacity  ){

                        dest[destIndex] = profile->mappingData[index+i];

                    }

                    destIndex++; /* for pre-flighting */

                }  

                continue;

            }else{

                // subtract the delta to arrive at the code point

                ch -= value;

            }

        }else if(type==USPREP_DELETE){

             // just consume the codepoint and contine

            continue;

        }

        //copy the code point into destination

        if(ch <= 0xFFFF){

            if(destIndex < destCapacity ){

                dest[destIndex] = (UChar)ch;

            }

            destIndex++;

        }else{

            if(destIndex+1 < destCapacity ){

                dest[destIndex]   = U16_LEAD(ch);

                dest[destIndex+1] = U16_TRAIL(ch);

            }

            destIndex +=2;

        }

    }

    return u_terminateUChars(dest, destCapacity, destIndex, status);

}

/*

   1) Map -- For each character in the input, check if it has a mapping

      and, if so, replace it with its mapping.  

   2) Normalize -- Possibly normalize the result of step 1 using Unicode

      normalization. 

   3) Prohibit -- Check for any characters that are not allowed in the

      output.  If any are found, return an error.  

   4) Check bidi -- Possibly check for right-to-left characters, and if

      any are found, make sure that the whole string satisfies the

      requirements for bidirectional strings.  If the string does not

      satisfy the requirements for bidirectional strings, return an

      error.  

      [Unicode3.2] defines several bidirectional categories; each character

       has one bidirectional category assigned to it.  For the purposes of

       the requirements below, an "RandALCat character" is a character that

       has Unicode bidirectional categories "R" or "AL"; an "LCat character"

       is a character that has Unicode bidirectional category "L".  Note

       that there are many characters which fall in neither of the above

       definitions; Latin digits (<U+0030> through <U+0039>) are examples of

       this because they have bidirectional category "EN".

       In any profile that specifies bidirectional character handling, all

       three of the following requirements MUST be met:

       1) The characters in section 5.8 MUST be prohibited.

       2) If a string contains any RandALCat character, the string MUST NOT

          contain any LCat character.

       3) If a string contains any RandALCat character, a RandALCat

          character MUST be the first character of the string, and a

          RandALCat character MUST be the last character of the string.

*/

U_CAPI int32_t U_EXPORT2

usprep_prepare(   const UStringPrepProfile* profile,

                  const UChar* src, int32_t srcLength, 

                  UChar* dest, int32_t destCapacity,

                  int32_t options,

                  UParseError* parseError,

                  UErrorCode* status ){

    // check error status

    if(U_FAILURE(*status)){

        return 0;

    }

    //check arguments

    if(profile==NULL ||

            (src==NULL ? srcLength!=0 : srcLength<-1) ||

            (dest==NULL ? destCapacity!=0 : destCapacity<0)) {

        *status=U_ILLEGAL_ARGUMENT_ERROR;

        return 0;

    }

    //get the string length

    if(srcLength < 0){

        srcLength = u_strlen(src);

    }

    // map

    UnicodeString s1;

    UChar *b1 = s1.getBuffer(srcLength);

    if(b1==NULL){

        *status = U_MEMORY_ALLOCATION_ERROR;

        return 0;

    }

    int32_t b1Len = usprep_map(profile, src, srcLength,

                               b1, s1.getCapacity(), options, parseError, status);

    s1.releaseBuffer(U_SUCCESS(*status) ? b1Len : 0);

    if(*status == U_BUFFER_OVERFLOW_ERROR){

        // redo processing of string

        /* we do not have enough room so grow the buffer*/

        b1 = s1.getBuffer(b1Len);

        if(b1==NULL){

            *status = U_MEMORY_ALLOCATION_ERROR;

            return 0;

        }

        *status = U_ZERO_ERROR; // reset error

        b1Len = usprep_map(profile, src, srcLength,

                           b1, s1.getCapacity(), options, parseError, status);

        s1.releaseBuffer(U_SUCCESS(*status) ? b1Len : 0);

    }

    if(U_FAILURE(*status)){

        return 0;

    }

    // normalize

    UnicodeString s2;

    if(profile->doNFKC){

        const Normalizer2 *n2 = Normalizer2::getNFKCInstance(*status);

        FilteredNormalizer2 fn2(*n2, *uniset_getUnicode32Instance(*status));

        if(U_FAILURE(*status)){

            return 0;

        }

        fn2.normalize(s1, s2, *status);

    }else{

        s2.fastCopyFrom(s1);

    }

    if(U_FAILURE(*status)){

        return 0;

    }

    // Prohibit and checkBiDi in one pass

    const UChar *b2 = s2.getBuffer();

    int32_t b2Len = s2.length();

    UCharDirection direction=U_CHAR_DIRECTION_COUNT, firstCharDir=U_CHAR_DIRECTION_COUNT;

    UBool leftToRight=FALSE, rightToLeft=FALSE;

    int32_t rtlPos =-1, ltrPos =-1;

    for(int32_t b2Index=0; b2Index<b2Len;){

        UChar32 ch = 0;

        U16_NEXT(b2, b2Index, b2Len, ch);

        uint16_t result;

        UTRIE_GET16(&profile->sprepTrie,ch,result);

        int16_t value;

        UBool isIndex;

        UStringPrepType type = getValues(result, value, isIndex);

        if( type == USPREP_PROHIBITED || 

            ((result < _SPREP_TYPE_THRESHOLD) && (result & 0x01) /* first bit says it the code point is prohibited*/)

           ){

            *status = U_STRINGPREP_PROHIBITED_ERROR;

            uprv_syntaxError(b1, b2Index-U16_LENGTH(ch), b2Len, parseError);

            return 0;

        }

        if(profile->checkBiDi) {

            direction = ubidi_getClass(ch);

            if(firstCharDir == U_CHAR_DIRECTION_COUNT){

                firstCharDir = direction;

            }

            if(direction == U_LEFT_TO_RIGHT){

                leftToRight = TRUE;

                ltrPos = b2Index-1;

            }

            if(direction == U_RIGHT_TO_LEFT || direction == U_RIGHT_TO_LEFT_ARABIC){

                rightToLeft = TRUE;

                rtlPos = b2Index-1;

            }

        }

    }

    if(profile->checkBiDi == TRUE){

        // satisfy 2

        if( leftToRight == TRUE && rightToLeft == TRUE){

            *status = U_STRINGPREP_CHECK_BIDI_ERROR;

            uprv_syntaxError(b2,(rtlPos>ltrPos) ? rtlPos : ltrPos, b2Len, parseError);

            return 0;

        }

        //satisfy 3

        if( rightToLeft == TRUE && 

            !((firstCharDir == U_RIGHT_TO_LEFT || firstCharDir == U_RIGHT_TO_LEFT_ARABIC) &&

              (direction == U_RIGHT_TO_LEFT || direction == U_RIGHT_TO_LEFT_ARABIC))

           ){

            *status = U_STRINGPREP_CHECK_BIDI_ERROR;

            uprv_syntaxError(b2, rtlPos, b2Len, parseError);

            return FALSE;

        }

    }

    return s2.extract(dest, destCapacity, *status);

}

/* data swapping ------------------------------------------------------------ */

U_CAPI int32_t U_EXPORT2

usprep_swap(const UDataSwapper *ds,

            const void *inData, int32_t length, void *outData,

            UErrorCode *pErrorCode) {

    const UDataInfo *pInfo;

    int32_t headerSize;

    const uint8_t *inBytes;

    uint8_t *outBytes;

    const int32_t *inIndexes;

    int32_t indexes[16];

    int32_t i, offset, count, size;

    /* udata_swapDataHeader checks the arguments */

    headerSize=udata_swapDataHeader(ds, inData, length, outData, pErrorCode);

    if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {

        return 0;

    }

    /* check data format and format version */

    pInfo=(const UDataInfo *)((const char *)inData+4);

    if(!(

        pInfo->dataFormat[0]==0x53 &&   /* dataFormat="SPRP" */

        pInfo->dataFormat[1]==0x50 &&

        pInfo->dataFormat[2]==0x52 &&

        pInfo->dataFormat[3]==0x50 &&

        pInfo->formatVersion[0]==3

    )) {

        udata_printError(ds, "usprep_swap(): data format %02x.%02x.%02x.%02x (format version %02x) is not recognized as StringPrep .spp data\n",

                         pInfo->dataFormat[0], pInfo->dataFormat[1],

                         pInfo->dataFormat[2], pInfo->dataFormat[3],

                         pInfo->formatVersion[0]);

        *pErrorCode=U_UNSUPPORTED_ERROR;

        return 0;

    }

    inBytes=(const uint8_t *)inData+headerSize;

    outBytes=(uint8_t *)outData+headerSize;

    inIndexes=(const int32_t *)inBytes;

    if(length>=0) {

        length-=headerSize;

        if(length<16*4) {

            udata_printError(ds, "usprep_swap(): too few bytes (%d after header) for StringPrep .spp data\n",

                             length);

            *pErrorCode=U_INDEX_OUTOFBOUNDS_ERROR;

            return 0;

        }

    }

    /* read the first 16 indexes (ICU 2.8/format version 3: _SPREP_INDEX_TOP==16, might grow) */

    for(i=0; i<16; ++i) {

        indexes[i]=udata_readInt32(ds, inIndexes[i]);

    }

    /* calculate the total length of the data */

    size=

        16*4+ /* size of indexes[] */

        indexes[_SPREP_INDEX_TRIE_SIZE]+

        indexes[_SPREP_INDEX_MAPPING_DATA_SIZE];

    if(length>=0) {

        if(length<size) {

            udata_printError(ds, "usprep_swap(): too few bytes (%d after header) for all of StringPrep .spp data\n",

                             length);

            *pErrorCode=U_INDEX_OUTOFBOUNDS_ERROR;

            return 0;

        }

        /* copy the data for inaccessible bytes */

        if(inBytes!=outBytes) {

            uprv_memcpy(outBytes, inBytes, size);

        }

        offset=0;

        /* swap the int32_t indexes[] */

        count=16*4;

        ds->swapArray32(ds, inBytes, count, outBytes, pErrorCode);

        offset+=count;

        /* swap the UTrie */

        count=indexes[_SPREP_INDEX_TRIE_SIZE];

        utrie_swap(ds, inBytes+offset, count, outBytes+offset, pErrorCode);

        offset+=count;

        /* swap the uint16_t mappingTable[] */

        count=indexes[_SPREP_INDEX_MAPPING_DATA_SIZE];

        ds->swapArray16(ds, inBytes+offset, count, outBytes+offset, pErrorCode);

        //offset+=count;

    }