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gencnvex.c (35007B)


      1 // © 2016 and later: Unicode, Inc. and others.
      2 // License & terms of use: http://www.unicode.org/copyright.html
      3 /*
      4 *******************************************************************************
      5 *
      6 *   Copyright (C) 2003-2014, International Business Machines
      7 *   Corporation and others.  All Rights Reserved.
      8 *
      9 *******************************************************************************
     10 *   file name:  gencnvex.c
     11 *   encoding:   UTF-8
     12 *   tab size:   8 (not used)
     13 *   indentation:4
     14 *
     15 *   created on: 2003oct12
     16 *   created by: Markus W. Scherer
     17 */
     18 
     19 #include <stdbool.h>
     20 #include <stdio.h>
     21 #include "unicode/utypes.h"
     22 #include "unicode/ustring.h"
     23 #include "cstring.h"
     24 #include "cmemory.h"
     25 #include "ucnv_cnv.h"
     26 #include "ucnvmbcs.h"
     27 #include "toolutil.h"
     28 #include "unewdata.h"
     29 #include "ucm.h"
     30 #include "makeconv.h"
     31 #include "genmbcs.h"
     32 
     33 static void
     34 CnvExtClose(NewConverter *cnvData);
     35 
     36 static UBool
     37 CnvExtIsValid(NewConverter *cnvData,
     38              const uint8_t *bytes, int32_t length);
     39 
     40 static UBool
     41 CnvExtAddTable(NewConverter *cnvData, UCMTable *table, UConverterStaticData *staticData);
     42 
     43 static uint32_t
     44 CnvExtWrite(NewConverter *cnvData, const UConverterStaticData *staticData,
     45            UNewDataMemory *pData, int32_t tableType);
     46 
     47 typedef struct CnvExtData {
     48    NewConverter newConverter;
     49 
     50    UCMFile *ucm;
     51 
     52    /* toUnicode (state table in ucm->states) */
     53    UToolMemory *toUTable, *toUUChars;
     54 
     55    /* fromUnicode */
     56    UToolMemory *fromUTableUChars, *fromUTableValues, *fromUBytes;
     57 
     58    uint16_t stage1[MBCS_STAGE_1_SIZE];
     59    uint16_t stage2[MBCS_STAGE_2_SIZE];
     60    uint16_t stage3[0x10000<<UCNV_EXT_STAGE_2_LEFT_SHIFT]; /* 0x10000 because of 16-bit stage 2/3 indexes */
     61    uint32_t stage3b[0x10000];
     62 
     63    int32_t stage1Top, stage2Top, stage3Top, stage3bTop;
     64 
     65    /* for stage3 compaction of <subchar1> |2 mappings */
     66    uint16_t stage3Sub1Block;
     67 
     68    /* statistics */
     69    int32_t
     70        maxInBytes, maxOutBytes, maxBytesPerUChar,
     71        maxInUChars, maxOutUChars, maxUCharsPerByte;
     72 } CnvExtData;
     73 
     74 NewConverter *
     75 CnvExtOpen(UCMFile *ucm) {
     76    CnvExtData *extData;
     77    
     78    extData=(CnvExtData *)uprv_malloc(sizeof(CnvExtData));
     79    if(extData==NULL) {
     80        printf("out of memory\n");
     81        exit(U_MEMORY_ALLOCATION_ERROR);
     82    }
     83    uprv_memset(extData, 0, sizeof(CnvExtData));
     84 
     85    extData->ucm=ucm; /* aliased, not owned */
     86 
     87    extData->newConverter.close=CnvExtClose;
     88    extData->newConverter.isValid=CnvExtIsValid;
     89    extData->newConverter.addTable=CnvExtAddTable;
     90    extData->newConverter.write=CnvExtWrite;
     91    return &extData->newConverter;
     92 }
     93 
     94 static void
     95 CnvExtClose(NewConverter *cnvData) {
     96    CnvExtData *extData=(CnvExtData *)cnvData;
     97    if(extData!=NULL) {
     98        utm_close(extData->toUTable);
     99        utm_close(extData->toUUChars);
    100        utm_close(extData->fromUTableUChars);
    101        utm_close(extData->fromUTableValues);
    102        utm_close(extData->fromUBytes);
    103        uprv_free(extData);
    104    }
    105 }
    106 
    107 /* we do not expect this to be called */
    108 static UBool
    109 CnvExtIsValid(NewConverter *cnvData,
    110        const uint8_t *bytes, int32_t length) {
    111    // suppress compiler warnings about unused variables
    112    (void)cnvData;
    113    (void)bytes;
    114    (void)length;
    115    return false;
    116 }
    117 
    118 static uint32_t
    119 CnvExtWrite(NewConverter *cnvData, const UConverterStaticData *staticData,
    120            UNewDataMemory *pData, int32_t tableType) {
    121    (void) staticData; // suppress compiler warnings about unused variable
    122    CnvExtData *extData=(CnvExtData *)cnvData;
    123    int32_t length, top, headerSize;
    124 
    125    int32_t indexes[UCNV_EXT_INDEXES_MIN_LENGTH]={ 0 };
    126 
    127    if(tableType&TABLE_BASE) {
    128        headerSize=0;
    129    } else {
    130        _MBCSHeader header={ { 0, 0, 0, 0 }, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
    131 
    132        /* write the header and base table name for an extension-only table */
    133        length=(int32_t)uprv_strlen(extData->ucm->baseName)+1;
    134        while(length&3) {
    135            /* add padding */
    136            extData->ucm->baseName[length++]=0;
    137        }
    138 
    139        headerSize=MBCS_HEADER_V4_LENGTH*4+length;
    140 
    141        /* fill the header */
    142        header.version[0]=4;
    143        header.version[1]=2;
    144        header.flags=(uint32_t)((headerSize<<8)|MBCS_OUTPUT_EXT_ONLY);
    145 
    146        /* write the header and the base table name */
    147        udata_writeBlock(pData, &header, MBCS_HEADER_V4_LENGTH*4);
    148        udata_writeBlock(pData, extData->ucm->baseName, length);
    149    }
    150 
    151    /* fill indexes[] - offsets/indexes are in units of the target array */
    152    top=0;
    153 
    154    indexes[UCNV_EXT_INDEXES_LENGTH]=length=UCNV_EXT_INDEXES_MIN_LENGTH;
    155    top+=length*4;
    156 
    157    indexes[UCNV_EXT_TO_U_INDEX]=top;
    158    indexes[UCNV_EXT_TO_U_LENGTH]=length=utm_countItems(extData->toUTable);
    159    top+=length*4;
    160 
    161    indexes[UCNV_EXT_TO_U_UCHARS_INDEX]=top;
    162    indexes[UCNV_EXT_TO_U_UCHARS_LENGTH]=length=utm_countItems(extData->toUUChars);
    163    top+=length*2;
    164 
    165    indexes[UCNV_EXT_FROM_U_UCHARS_INDEX]=top;
    166    length=utm_countItems(extData->fromUTableUChars);
    167    top+=length*2;
    168 
    169    if(top&3) {
    170        /* add padding */
    171        *((UChar *)utm_alloc(extData->fromUTableUChars))=0;
    172        *((uint32_t *)utm_alloc(extData->fromUTableValues))=0;
    173        ++length;
    174        top+=2;
    175    }
    176    indexes[UCNV_EXT_FROM_U_LENGTH]=length;
    177 
    178    indexes[UCNV_EXT_FROM_U_VALUES_INDEX]=top;
    179    top+=length*4;
    180 
    181    indexes[UCNV_EXT_FROM_U_BYTES_INDEX]=top;
    182    length=utm_countItems(extData->fromUBytes);
    183    top+=length;
    184 
    185    if(top&1) {
    186        /* add padding */
    187        *((uint8_t *)utm_alloc(extData->fromUBytes))=0;
    188        ++length;
    189        ++top;
    190    }
    191    indexes[UCNV_EXT_FROM_U_BYTES_LENGTH]=length;
    192 
    193    indexes[UCNV_EXT_FROM_U_STAGE_12_INDEX]=top;
    194    indexes[UCNV_EXT_FROM_U_STAGE_1_LENGTH]=length=extData->stage1Top;
    195    indexes[UCNV_EXT_FROM_U_STAGE_12_LENGTH]=length+=extData->stage2Top;
    196    top+=length*2;
    197 
    198    indexes[UCNV_EXT_FROM_U_STAGE_3_INDEX]=top;
    199    length=extData->stage3Top;
    200    top+=length*2;
    201 
    202    if(top&3) {
    203        /* add padding */
    204        extData->stage3[extData->stage3Top++]=0;
    205        ++length;
    206        top+=2;
    207    }
    208    indexes[UCNV_EXT_FROM_U_STAGE_3_LENGTH]=length;
    209 
    210    indexes[UCNV_EXT_FROM_U_STAGE_3B_INDEX]=top;
    211    indexes[UCNV_EXT_FROM_U_STAGE_3B_LENGTH]=length=extData->stage3bTop;
    212    top+=length*4;
    213 
    214    indexes[UCNV_EXT_SIZE]=top;
    215 
    216    /* statistics */
    217    indexes[UCNV_EXT_COUNT_BYTES]=
    218        (extData->maxInBytes<<16)|
    219        (extData->maxOutBytes<<8)|
    220        extData->maxBytesPerUChar;
    221    indexes[UCNV_EXT_COUNT_UCHARS]=
    222        (extData->maxInUChars<<16)|
    223        (extData->maxOutUChars<<8)|
    224        extData->maxUCharsPerByte;
    225 
    226    indexes[UCNV_EXT_FLAGS]=extData->ucm->ext->unicodeMask;
    227 
    228    /* write the extension data */
    229    udata_writeBlock(pData, indexes, sizeof(indexes));
    230    udata_writeBlock(pData, utm_getStart(extData->toUTable), indexes[UCNV_EXT_TO_U_LENGTH]*4);
    231    udata_writeBlock(pData, utm_getStart(extData->toUUChars), indexes[UCNV_EXT_TO_U_UCHARS_LENGTH]*2);
    232 
    233    udata_writeBlock(pData, utm_getStart(extData->fromUTableUChars), indexes[UCNV_EXT_FROM_U_LENGTH]*2);
    234    udata_writeBlock(pData, utm_getStart(extData->fromUTableValues), indexes[UCNV_EXT_FROM_U_LENGTH]*4);
    235    udata_writeBlock(pData, utm_getStart(extData->fromUBytes), indexes[UCNV_EXT_FROM_U_BYTES_LENGTH]);
    236 
    237    udata_writeBlock(pData, extData->stage1, extData->stage1Top*2);
    238    udata_writeBlock(pData, extData->stage2, extData->stage2Top*2);
    239    udata_writeBlock(pData, extData->stage3, extData->stage3Top*2);
    240    udata_writeBlock(pData, extData->stage3b, extData->stage3bTop*4);
    241 
    242 #if 0
    243    {
    244        int32_t i, j;
    245 
    246        length=extData->stage1Top;
    247        printf("\nstage1[%x]:\n", length);
    248 
    249        for(i=0; i<length; ++i) {
    250            if(extData->stage1[i]!=length) {
    251                printf("stage1[%04x]=%04x\n", i, extData->stage1[i]);
    252            }
    253        }
    254 
    255        j=length;
    256        length=extData->stage2Top;
    257        printf("\nstage2[%x]:\n", length);
    258 
    259        for(i=0; i<length; ++j, ++i) {
    260            if(extData->stage2[i]!=0) {
    261                printf("stage12[%04x]=%04x\n", j, extData->stage2[i]);
    262            }
    263        }
    264 
    265        length=extData->stage3Top;
    266        printf("\nstage3[%x]:\n", length);
    267 
    268        for(i=0; i<length; ++i) {
    269            if(extData->stage3[i]!=0) {
    270                printf("stage3[%04x]=%04x\n", i, extData->stage3[i]);
    271            }
    272        }
    273 
    274        length=extData->stage3bTop;
    275        printf("\nstage3b[%x]:\n", length);
    276 
    277        for(i=0; i<length; ++i) {
    278            if(extData->stage3b[i]!=0) {
    279                printf("stage3b[%04x]=%08x\n", i, extData->stage3b[i]);
    280            }
    281        }
    282    }
    283 #endif
    284 
    285    if(VERBOSE) {
    286        printf("size of extension data: %ld\n", (long)top);
    287    }
    288 
    289    /* return the number of bytes that should have been written */
    290    return (uint32_t)(headerSize+top);
    291 }
    292 
    293 /* to Unicode --------------------------------------------------------------- */
    294 
    295 /*
    296 * Remove fromUnicode fallbacks and SUB mappings which are irrelevant for
    297 * the toUnicode table.
    298 * This includes mappings with MBCS_FROM_U_EXT_FLAG which were suitable
    299 * for the base toUnicode table but not for the base fromUnicode table.
    300 * The table must be sorted.
    301 * Modifies previous data in the reverseMap.
    302 */
    303 static int32_t
    304 reduceToUMappings(UCMTable *table) {
    305    UCMapping *mappings;
    306    int32_t *map;
    307    int32_t i, j, count;
    308    int8_t flag;
    309 
    310    mappings=table->mappings;
    311    map=table->reverseMap;
    312    count=table->mappingsLength;
    313 
    314    /* leave the map alone for the initial mappings with desired flags */
    315    for(i=j=0; i<count; ++i) {
    316        flag=mappings[map[i]].f;
    317        if(flag!=0 && flag!=3) {
    318            break;
    319        }
    320    }
    321 
    322    /* reduce from here to the rest */
    323    for(j=i; i<count; ++i) {
    324        flag=mappings[map[i]].f;
    325        if(flag==0 || flag==3) {
    326            map[j++]=map[i];
    327        }
    328    }
    329 
    330    return j;
    331 }
    332 
    333 static uint32_t
    334 getToUnicodeValue(CnvExtData *extData, UCMTable *table, UCMapping *m) {
    335    UChar32 *u32;
    336    UChar *u;
    337    uint32_t value;
    338    int32_t u16Length, ratio;
    339    UErrorCode errorCode;
    340 
    341    /* write the Unicode result code point or string index */
    342    if(m->uLen==1) {
    343        u16Length=U16_LENGTH(m->u);
    344        value=(uint32_t)(UCNV_EXT_TO_U_MIN_CODE_POINT+m->u);
    345    } else {
    346        /* the parser enforces m->uLen<=UCNV_EXT_MAX_UCHARS */
    347 
    348        /* get the result code point string and its 16-bit string length */
    349        u32=UCM_GET_CODE_POINTS(table, m);
    350        errorCode=U_ZERO_ERROR;
    351        u_strFromUTF32(NULL, 0, &u16Length, u32, m->uLen, &errorCode);
    352        if(U_FAILURE(errorCode) && errorCode!=U_BUFFER_OVERFLOW_ERROR) {
    353            exit(errorCode);
    354        }
    355 
    356        /* allocate it and put its length and index into the value */
    357        value=
    358            (((uint32_t)u16Length+UCNV_EXT_TO_U_LENGTH_OFFSET)<<UCNV_EXT_TO_U_LENGTH_SHIFT)|
    359            ((uint32_t)utm_countItems(extData->toUUChars));
    360        u=utm_allocN(extData->toUUChars, u16Length);
    361 
    362        /* write the result 16-bit string */
    363        errorCode=U_ZERO_ERROR;
    364        u_strFromUTF32(u, u16Length, NULL, u32, m->uLen, &errorCode);
    365        if(U_FAILURE(errorCode) && errorCode!=U_BUFFER_OVERFLOW_ERROR) {
    366            exit(errorCode);
    367        }
    368    }
    369    if(m->f==0) {
    370        value|=UCNV_EXT_TO_U_ROUNDTRIP_FLAG;
    371    }
    372 
    373    /* update statistics */
    374    if(m->bLen>extData->maxInBytes) {
    375        extData->maxInBytes=m->bLen;
    376    }
    377    if(u16Length>extData->maxOutUChars) {
    378        extData->maxOutUChars=u16Length;
    379    }
    380 
    381    ratio=(u16Length+(m->bLen-1))/m->bLen;
    382    if(ratio>extData->maxUCharsPerByte) {
    383        extData->maxUCharsPerByte=ratio;
    384    }
    385 
    386    return value;
    387 }
    388 
    389 /*
    390 * Recursive toUTable generator core function.
    391 * Preconditions:
    392 * - start<limit (There is at least one mapping.)
    393 * - The mappings are sorted lexically. (Access is through the reverseMap.)
    394 * - All mappings between start and limit have input sequences that share
    395 *   the same prefix of unitIndex length, and therefore all of these sequences
    396 *   are at least unitIndex+1 long.
    397 * - There are only relevant mappings available through the reverseMap,
    398 *   see reduceToUMappings().
    399 *
    400 * One function invocation generates one section table.
    401 *
    402 * Steps:
    403 * 1. Count the number of unique unit values and get the low/high unit values
    404 *    that occur at unitIndex.
    405 * 2. Allocate the section table with possible optimization for linear access.
    406 * 3. Write temporary version of the section table with start indexes of
    407 *    subsections, each corresponding to one unit value at unitIndex.
    408 * 4. Iterate through the table once more, and depending on the subsection length:
    409 *    0: write 0 as a result value (unused byte in linear-access section table)
    410 *   >0: if there is one mapping with an input unit sequence of unitIndex+1
    411 *       then defaultValue=compute the mapping result for this whole sequence
    412 *       else defaultValue=0
    413 *
    414 *       recurse into the subsection
    415 */
    416 static UBool
    417 generateToUTable(CnvExtData *extData, UCMTable *table,
    418                 int32_t start, int32_t limit, int32_t unitIndex,
    419                 uint32_t defaultValue) {
    420    UCMapping *mappings, *m;
    421    int32_t *map;
    422    int32_t i, j, uniqueCount, count, subStart, subLimit;
    423 
    424    uint8_t *bytes;
    425    int32_t low, high, prev;
    426 
    427    uint32_t *section;
    428 
    429    mappings=table->mappings;
    430    map=table->reverseMap;
    431 
    432    /* step 1: examine the input units; set low, high, uniqueCount */
    433    m=mappings+map[start];
    434    bytes=UCM_GET_BYTES(table, m);
    435    low=bytes[unitIndex];
    436    uniqueCount=1;
    437 
    438    prev=high=low;
    439    for(i=start+1; i<limit; ++i) {
    440        m=mappings+map[i];
    441        bytes=UCM_GET_BYTES(table, m);
    442        high=bytes[unitIndex];
    443 
    444        if(high!=prev) {
    445            prev=high;
    446            ++uniqueCount;
    447        }
    448    }
    449 
    450    /* step 2: allocate the section; set count, section */
    451    count=(high-low)+1;
    452    if(count<0x100 && (unitIndex==0 || uniqueCount>=(3*count)/4)) {
    453        /*
    454         * for the root table and for fairly full tables:
    455         * allocate for direct, linear array access
    456         * by keeping count, to write an entry for each unit value
    457         * from low to high
    458         * exception: use a compact table if count==0x100 because
    459         * that cannot be encoded in the length byte
    460         */
    461    } else {
    462        count=uniqueCount;
    463    }
    464 
    465    if(count>=0x100) {
    466        fprintf(stderr, "error: toUnicode extension table section overflow: %ld section entries\n", (long)count);
    467        return false;
    468    }
    469 
    470    /* allocate the section: 1 entry for the header + count for the items */
    471    section=(uint32_t *)utm_allocN(extData->toUTable, 1+count);
    472 
    473    /* write the section header */
    474    *section++=((uint32_t)count<<UCNV_EXT_TO_U_BYTE_SHIFT)|defaultValue;
    475 
    476    /* step 3: write temporary section table with subsection starts */
    477    prev=low-1; /* just before low to prevent empty subsections before low */
    478    j=0; /* section table index */
    479    for(i=start; i<limit; ++i) {
    480        m=mappings+map[i];
    481        bytes=UCM_GET_BYTES(table, m);
    482        high=bytes[unitIndex];
    483 
    484        if(high!=prev) {
    485            /* start of a new subsection for unit high */
    486            if(count>uniqueCount) {
    487                /* write empty subsections for unused units in a linear table */
    488                while(++prev<high) {
    489                    section[j++]=((uint32_t)prev<<UCNV_EXT_TO_U_BYTE_SHIFT)|(uint32_t)i;
    490                }
    491            } else {
    492                prev=high;
    493            }
    494 
    495            /* write the entry with the subsection start */
    496            section[j++]=((uint32_t)high<<UCNV_EXT_TO_U_BYTE_SHIFT)|(uint32_t)i;
    497        }
    498    }
    499    /* assert(j==count) */
    500 
    501    /* step 4: recurse and write results */
    502    subLimit=UCNV_EXT_TO_U_GET_VALUE(section[0]);
    503    for(j=0; j<count; ++j) {
    504        subStart=subLimit;
    505        subLimit= (j+1)<count ? (int32_t)UCNV_EXT_TO_U_GET_VALUE(section[j+1]) : limit;
    506 
    507        /* remove the subStart temporary value */
    508        section[j]&=~UCNV_EXT_TO_U_VALUE_MASK;
    509 
    510        if(subStart==subLimit) {
    511            /* leave the value zero: empty subsection for unused unit in a linear table */
    512            continue;
    513        }
    514 
    515        /* see if there is exactly one input unit sequence of length unitIndex+1 */
    516        defaultValue=0;
    517        m=mappings+map[subStart];
    518        if(m->bLen==unitIndex+1) {
    519            /* do not include this in generateToUTable() */
    520            ++subStart;
    521 
    522            if(subStart<subLimit && mappings[map[subStart]].bLen==unitIndex+1) {
    523                /* print error for multiple same-input-sequence mappings */
    524                fprintf(stderr, "error: multiple mappings from same bytes\n");
    525                ucm_printMapping(table, m, stderr);
    526                ucm_printMapping(table, mappings+map[subStart], stderr);
    527                return false;
    528            }
    529 
    530            defaultValue=getToUnicodeValue(extData, table, m);
    531        }
    532 
    533        if(subStart==subLimit) {
    534            /* write the result for the input sequence ending here */
    535            section[j]|=defaultValue;
    536        } else {
    537            /* write the index to the subsection table */
    538            section[j]|=(uint32_t)utm_countItems(extData->toUTable);
    539 
    540            /* recurse */
    541            if(!generateToUTable(extData, table, subStart, subLimit, unitIndex+1, defaultValue)) {
    542                return false;
    543            }
    544        }
    545    }
    546    return true;
    547 }
    548 
    549 /*
    550 * Generate the toUTable and toUUChars from the input table.
    551 * The input table must be sorted, and all precision flags must be 0..3.
    552 * This function will modify the table's reverseMap.
    553 */
    554 static UBool
    555 makeToUTable(CnvExtData *extData, UCMTable *table) {
    556    int32_t toUCount;
    557 
    558    toUCount=reduceToUMappings(table);
    559 
    560    extData->toUTable=utm_open("cnv extension toUTable", 0x10000, UCNV_EXT_TO_U_MIN_CODE_POINT, 4);
    561    extData->toUUChars=utm_open("cnv extension toUUChars", 0x10000, UCNV_EXT_TO_U_INDEX_MASK+1, 2);
    562 
    563    return generateToUTable(extData, table, 0, toUCount, 0, 0);
    564 }
    565 
    566 /* from Unicode ------------------------------------------------------------- */
    567 
    568 /*
    569 * preprocessing:
    570 * rebuild reverseMap with mapping indexes for mappings relevant for from Unicode
    571 * change each Unicode string to encode all but the first code point in 16-bit form
    572 *
    573 * generation:
    574 * for each unique code point
    575 *   write an entry in the 3-stage trie
    576 *   check that there is only one single-code point sequence
    577 *   start recursion for following 16-bit input units
    578 */
    579 
    580 /*
    581 * Remove toUnicode fallbacks and non-<subchar1> SUB mappings
    582 * which are irrelevant for the fromUnicode extension table.
    583 * Remove MBCS_FROM_U_EXT_FLAG bits.
    584 * Overwrite the reverseMap with an index array to the relevant mappings.
    585 * Modify the code point sequences to a generator-friendly format where
    586 * the first code points remains unchanged but the following are recoded
    587 * into 16-bit Unicode string form.
    588 * The table must be sorted.
    589 * Destroys previous data in the reverseMap.
    590 */
    591 static int32_t
    592 prepareFromUMappings(UCMTable *table) {
    593    UCMapping *mappings, *m;
    594    int32_t *map;
    595    int32_t i, j, count;
    596    int8_t flag;
    597 
    598    mappings=table->mappings;
    599    map=table->reverseMap;
    600    count=table->mappingsLength;
    601 
    602    /*
    603     * we do not go through the map on input because the mappings are
    604     * sorted lexically
    605     */
    606    m=mappings;
    607 
    608    for(i=j=0; i<count; ++m, ++i) {
    609        flag=m->f;
    610        if(flag>=0) {
    611            flag&=MBCS_FROM_U_EXT_MASK;
    612            m->f=flag;
    613        }
    614        if(flag==0 || flag==1 || (flag==2 && m->bLen==1) || flag==4) {
    615            map[j++]=i;
    616 
    617            if(m->uLen>1) {
    618                /* recode all but the first code point to 16-bit Unicode */
    619                UChar32 *u32;
    620                UChar *u;
    621                UChar32 c;
    622                int32_t q, r;
    623 
    624                u32=UCM_GET_CODE_POINTS(table, m);
    625                u=(UChar *)u32; /* destructive in-place recoding */
    626                for(r=2, q=1; q<m->uLen; ++q) {
    627                    c=u32[q];
    628                    U16_APPEND_UNSAFE(u, r, c);
    629                }
    630 
    631                /* counts the first code point always at 2 - the first 16-bit unit is at 16-bit index 2 */
    632                m->uLen=(int8_t)r;
    633            }
    634        }
    635    }
    636 
    637    return j;
    638 }
    639 
    640 static uint32_t
    641 getFromUBytesValue(CnvExtData *extData, UCMTable *table, UCMapping *m) {
    642    uint8_t *bytes, *resultBytes;
    643    uint32_t value;
    644    int32_t u16Length, ratio;
    645 
    646    if(m->f==2) {
    647        /*
    648         * no mapping, <subchar1> preferred
    649         *
    650         * no need to count in statistics because the subchars are already
    651         * counted for maxOutBytes and maxBytesPerUChar in UConverterStaticData,
    652         * and this non-mapping does not count for maxInUChars which are always
    653         * trivially at least two if counting unmappable supplementary code points
    654         */
    655        return UCNV_EXT_FROM_U_SUBCHAR1;
    656    }
    657 
    658    bytes=UCM_GET_BYTES(table, m);
    659    value=0;
    660    switch(m->bLen) {
    661        /* 1..3: store the bytes in the value word */
    662    case 3:
    663        value=((uint32_t)*bytes++)<<16;
    664        U_FALLTHROUGH;
    665    case 2:
    666        value|=((uint32_t)*bytes++)<<8;
    667        U_FALLTHROUGH;
    668    case 1:
    669        value|=*bytes;
    670        break;
    671    default:
    672        /* the parser enforces m->bLen<=UCNV_EXT_MAX_BYTES */
    673        /* store the bytes in fromUBytes[] and the index in the value word */
    674        value=(uint32_t)utm_countItems(extData->fromUBytes);
    675        resultBytes=utm_allocN(extData->fromUBytes, m->bLen);
    676        uprv_memcpy(resultBytes, bytes, m->bLen);
    677        break;
    678    }
    679    value|=(uint32_t)m->bLen<<UCNV_EXT_FROM_U_LENGTH_SHIFT;
    680    if(m->f==0) {
    681        value|=UCNV_EXT_FROM_U_ROUNDTRIP_FLAG;
    682    } else if(m->f==4) {
    683        value|=UCNV_EXT_FROM_U_GOOD_ONE_WAY_FLAG;
    684    }
    685 
    686    /* calculate the real UTF-16 length (see recoding in prepareFromUMappings()) */
    687    if(m->uLen==1) {
    688        u16Length=U16_LENGTH(m->u);
    689    } else {
    690        u16Length=U16_LENGTH(UCM_GET_CODE_POINTS(table, m)[0])+(m->uLen-2);
    691    }
    692 
    693    /* update statistics */
    694    if(u16Length>extData->maxInUChars) {
    695        extData->maxInUChars=u16Length;
    696    }
    697    if(m->bLen>extData->maxOutBytes) {
    698        extData->maxOutBytes=m->bLen;
    699    }
    700 
    701    ratio=(m->bLen+(u16Length-1))/u16Length;
    702    if(ratio>extData->maxBytesPerUChar) {
    703        extData->maxBytesPerUChar=ratio;
    704    }
    705 
    706    return value;
    707 }
    708 
    709 /*
    710 * works like generateToUTable(), except that the
    711 * output section consists of two arrays, one for input UChars and one
    712 * for result values
    713 *
    714 * also, fromUTable sections are always stored in a compact form for
    715 * access via binary search
    716 */
    717 static UBool
    718 generateFromUTable(CnvExtData *extData, UCMTable *table,
    719                   int32_t start, int32_t limit, int32_t unitIndex,
    720                   uint32_t defaultValue) {
    721    UCMapping *mappings, *m;
    722    int32_t *map;
    723    int32_t i, j, uniqueCount, count, subStart, subLimit;
    724 
    725    UChar *uchars;
    726    UChar32 low, high, prev;
    727 
    728    UChar *sectionUChars;
    729    uint32_t *sectionValues;
    730 
    731    mappings=table->mappings;
    732    map=table->reverseMap;
    733 
    734    /* step 1: examine the input units; set low, high, uniqueCount */
    735    m=mappings+map[start];
    736    uchars=(UChar *)UCM_GET_CODE_POINTS(table, m);
    737    low=uchars[unitIndex];
    738    uniqueCount=1;
    739 
    740    prev=high=low;
    741    for(i=start+1; i<limit; ++i) {
    742        m=mappings+map[i];
    743        uchars=(UChar *)UCM_GET_CODE_POINTS(table, m);
    744        high=uchars[unitIndex];
    745 
    746        if(high!=prev) {
    747            prev=high;
    748            ++uniqueCount;
    749        }
    750    }
    751 
    752    /* step 2: allocate the section; set count, section */
    753    /* the fromUTable always stores for access via binary search */
    754    count=uniqueCount;
    755 
    756    /* allocate the section: 1 entry for the header + count for the items */
    757    sectionUChars=(UChar *)utm_allocN(extData->fromUTableUChars, 1+count);
    758    sectionValues=(uint32_t *)utm_allocN(extData->fromUTableValues, 1+count);
    759 
    760    /* write the section header */
    761    *sectionUChars++=(UChar)count;
    762    *sectionValues++=defaultValue;
    763 
    764    /* step 3: write temporary section table with subsection starts */
    765    prev=low-1; /* just before low to prevent empty subsections before low */
    766    j=0; /* section table index */
    767    for(i=start; i<limit; ++i) {
    768        m=mappings+map[i];
    769        uchars=(UChar *)UCM_GET_CODE_POINTS(table, m);
    770        high=uchars[unitIndex];
    771 
    772        if(high!=prev) {
    773            /* start of a new subsection for unit high */
    774            prev=high;
    775 
    776            /* write the entry with the subsection start */
    777            sectionUChars[j]=(UChar)high;
    778            sectionValues[j]=(uint32_t)i;
    779            ++j;
    780        }
    781    }
    782    /* assert(j==count) */
    783 
    784    /* step 4: recurse and write results */
    785    subLimit=(int32_t)(sectionValues[0]);
    786    for(j=0; j<count; ++j) {
    787        subStart=subLimit;
    788        subLimit= (j+1)<count ? (int32_t)(sectionValues[j+1]) : limit;
    789 
    790        /* see if there is exactly one input unit sequence of length unitIndex+1 */
    791        defaultValue=0;
    792        m=mappings+map[subStart];
    793        if(m->uLen==unitIndex+1) {
    794            /* do not include this in generateToUTable() */
    795            ++subStart;
    796 
    797            if(subStart<subLimit && mappings[map[subStart]].uLen==unitIndex+1) {
    798                /* print error for multiple same-input-sequence mappings */
    799                fprintf(stderr, "error: multiple mappings from same Unicode code points\n");
    800                ucm_printMapping(table, m, stderr);
    801                ucm_printMapping(table, mappings+map[subStart], stderr);
    802                return false;
    803            }
    804 
    805            defaultValue=getFromUBytesValue(extData, table, m);
    806        }
    807 
    808        if(subStart==subLimit) {
    809            /* write the result for the input sequence ending here */
    810            sectionValues[j]=defaultValue;
    811        } else {
    812            /* write the index to the subsection table */
    813            sectionValues[j]=(uint32_t)utm_countItems(extData->fromUTableValues);
    814 
    815            /* recurse */
    816            if(!generateFromUTable(extData, table, subStart, subLimit, unitIndex+1, defaultValue)) {
    817                return false;
    818            }
    819        }
    820    }
    821    return true;
    822 }
    823 
    824 /*
    825 * add entries to the fromUnicode trie,
    826 * assume to be called with code points in ascending order
    827 * and use that to build the trie in precompacted form
    828 */
    829 static void
    830 addFromUTrieEntry(CnvExtData *extData, UChar32 c, uint32_t value) {
    831    int32_t i1, i2, i3, i3b, nextOffset, min, newBlock;
    832 
    833    if(value==0) {
    834        return;
    835    }
    836 
    837    /*
    838     * compute the index for each stage,
    839     * allocate a stage block if necessary,
    840     * and write the stage value
    841     */
    842    i1=c>>10;
    843    if(i1>=extData->stage1Top) {
    844        extData->stage1Top=i1+1;
    845    }
    846 
    847    nextOffset=(c>>4)&0x3f;
    848 
    849    if(extData->stage1[i1]==0) {
    850        /* allocate another block in stage 2; overlap with the previous block */
    851        newBlock=extData->stage2Top;
    852        min=newBlock-nextOffset; /* minimum block start with overlap */
    853        while(min<newBlock && extData->stage2[newBlock-1]==0) {
    854            --newBlock;
    855        }
    856 
    857        extData->stage1[i1]=(uint16_t)newBlock;
    858        extData->stage2Top=newBlock+MBCS_STAGE_2_BLOCK_SIZE;
    859        if(extData->stage2Top>UPRV_LENGTHOF(extData->stage2)) {
    860            fprintf(stderr, "error: too many stage 2 entries at U+%04x\n", (int)c);
    861            exit(U_MEMORY_ALLOCATION_ERROR);
    862        }
    863    }
    864 
    865    i2=extData->stage1[i1]+nextOffset;
    866    nextOffset=c&0xf;
    867 
    868    if(extData->stage2[i2]==0) {
    869        /* allocate another block in stage 3; overlap with the previous block */
    870        newBlock=extData->stage3Top;
    871        min=newBlock-nextOffset; /* minimum block start with overlap */
    872        while(min<newBlock && extData->stage3[newBlock-1]==0) {
    873            --newBlock;
    874        }
    875 
    876        /* round up to a multiple of stage 3 granularity >1 (similar to utrie.c) */
    877        newBlock=(newBlock+(UCNV_EXT_STAGE_3_GRANULARITY-1))&~(UCNV_EXT_STAGE_3_GRANULARITY-1);
    878        extData->stage2[i2]=(uint16_t)(newBlock>>UCNV_EXT_STAGE_2_LEFT_SHIFT);
    879 
    880        extData->stage3Top=newBlock+MBCS_STAGE_3_BLOCK_SIZE;
    881        if(extData->stage3Top>UPRV_LENGTHOF(extData->stage3)) {
    882            fprintf(stderr, "error: too many stage 3 entries at U+%04x\n", (int)c);
    883            exit(U_MEMORY_ALLOCATION_ERROR);
    884        }
    885    }
    886 
    887    i3=((int32_t)extData->stage2[i2]<<UCNV_EXT_STAGE_2_LEFT_SHIFT)+nextOffset;
    888    /*
    889     * assume extData->stage3[i3]==0 because we get
    890     * code points in strictly ascending order
    891     */
    892 
    893    if(value==UCNV_EXT_FROM_U_SUBCHAR1) {
    894        /* <subchar1> SUB mapping, see getFromUBytesValue() and prepareFromUMappings() */
    895        extData->stage3[i3]=1;
    896 
    897        /*
    898         * precompaction is not optimal for <subchar1> |2 mappings because
    899         * stage3 values for them are all the same, unlike for other mappings
    900         * which all have unique values;
    901         * use a simple compaction of reusing a whole block filled with these
    902         * mappings
    903         */
    904 
    905        /* is the entire block filled with <subchar1> |2 mappings? */
    906        if(nextOffset==MBCS_STAGE_3_BLOCK_SIZE-1) {
    907            for(min=i3-nextOffset;
    908                min<i3 && extData->stage3[min]==1;
    909                ++min) {}
    910 
    911            if(min==i3) {
    912                /* the entire block is filled with these mappings */
    913                if(extData->stage3Sub1Block!=0) {
    914                    /* point to the previous such block and remove this block from stage3 */
    915                    extData->stage2[i2]=extData->stage3Sub1Block;
    916                    extData->stage3Top-=MBCS_STAGE_3_BLOCK_SIZE;
    917                    uprv_memset(extData->stage3+extData->stage3Top, 0, MBCS_STAGE_3_BLOCK_SIZE*2);
    918                } else {
    919                    /* remember this block's stage2 entry */
    920                    extData->stage3Sub1Block=extData->stage2[i2];
    921                }
    922            }
    923        }
    924    } else {
    925        if((i3b=extData->stage3bTop++)>=UPRV_LENGTHOF(extData->stage3b)) {
    926            fprintf(stderr, "error: too many stage 3b entries at U+%04x\n", (int)c);
    927            exit(U_MEMORY_ALLOCATION_ERROR);
    928        }
    929 
    930        /* roundtrip or fallback mapping */
    931        extData->stage3[i3]=(uint16_t)i3b;
    932        extData->stage3b[i3b]=value;
    933    }
    934 }
    935 
    936 static UBool
    937 generateFromUTrie(CnvExtData *extData, UCMTable *table, int32_t mapLength) {
    938    UCMapping *mappings, *m;
    939    int32_t *map;
    940    uint32_t value;
    941    int32_t subStart, subLimit;
    942 
    943    UChar32 *codePoints;
    944    UChar32 c, next;
    945 
    946    if(mapLength==0) {
    947        return true;
    948    }
    949 
    950    mappings=table->mappings;
    951    map=table->reverseMap;
    952 
    953    /*
    954     * iterate over same-initial-code point mappings,
    955     * enter the initial code point into the trie,
    956     * and start a recursion on the corresponding mappings section
    957     * with generateFromUTable()
    958     */
    959    m=mappings+map[0];
    960    codePoints=UCM_GET_CODE_POINTS(table, m);
    961    next=codePoints[0];
    962    subLimit=0;
    963    while(subLimit<mapLength) {
    964        /* get a new subsection of mappings starting with the same code point */
    965        subStart=subLimit;
    966        c=next;
    967        while(next==c && ++subLimit<mapLength) {
    968            m=mappings+map[subLimit];
    969            codePoints=UCM_GET_CODE_POINTS(table, m);
    970            next=codePoints[0];
    971        }
    972 
    973        /*
    974         * compute the value for this code point;
    975         * if there is a mapping for this code point alone, it is at subStart
    976         * because the table is sorted lexically
    977         */
    978        value=0;
    979        m=mappings+map[subStart];
    980        codePoints=UCM_GET_CODE_POINTS(table, m);
    981        if(m->uLen==1) {
    982            /* do not include this in generateFromUTable() */
    983            ++subStart;
    984 
    985            if(subStart<subLimit && mappings[map[subStart]].uLen==1) {
    986                /* print error for multiple same-input-sequence mappings */
    987                fprintf(stderr, "error: multiple mappings from same Unicode code points\n");
    988                ucm_printMapping(table, m, stderr);
    989                ucm_printMapping(table, mappings+map[subStart], stderr);
    990                return false;
    991            }
    992 
    993            value=getFromUBytesValue(extData, table, m);
    994        }
    995 
    996        if(subStart==subLimit) {
    997            /* write the result for this one code point */
    998            addFromUTrieEntry(extData, c, value);
    999        } else {
   1000            /* write the index to the subsection table */
   1001            addFromUTrieEntry(extData, c, (uint32_t)utm_countItems(extData->fromUTableValues));
   1002 
   1003            /* recurse, starting from 16-bit-unit index 2, the first 16-bit unit after c */
   1004            if(!generateFromUTable(extData, table, subStart, subLimit, 2, value)) {
   1005                return false;
   1006            }
   1007        }
   1008    }
   1009    return true;
   1010 }
   1011 
   1012 /*
   1013 * Generate the fromU data structures from the input table.
   1014 * The input table must be sorted, and all precision flags must be 0..3.
   1015 * This function will modify the table's reverseMap.
   1016 */
   1017 static UBool
   1018 makeFromUTable(CnvExtData *extData, UCMTable *table) {
   1019    uint16_t *stage1;
   1020    int32_t i, stage1Top, fromUCount;
   1021 
   1022    fromUCount=prepareFromUMappings(table);
   1023 
   1024    extData->fromUTableUChars=utm_open("cnv extension fromUTableUChars", 0x10000, UCNV_EXT_FROM_U_DATA_MASK+1, 2);
   1025    extData->fromUTableValues=utm_open("cnv extension fromUTableValues", 0x10000, UCNV_EXT_FROM_U_DATA_MASK+1, 4);
   1026    extData->fromUBytes=utm_open("cnv extension fromUBytes", 0x10000, UCNV_EXT_FROM_U_DATA_MASK+1, 1);
   1027 
   1028    /* allocate all-unassigned stage blocks */
   1029    extData->stage2Top=MBCS_STAGE_2_FIRST_ASSIGNED;
   1030    extData->stage3Top=MBCS_STAGE_3_FIRST_ASSIGNED;
   1031 
   1032    /*
   1033     * stage 3b stores only unique values, and in
   1034     * index 0: 0 for "no mapping"
   1035     * index 1: "no mapping" with preference for <subchar1> rather than <subchar>
   1036     */
   1037    extData->stage3b[1]=UCNV_EXT_FROM_U_SUBCHAR1;
   1038    extData->stage3bTop=2;
   1039 
   1040    /* allocate the first entry in the fromUTable because index 0 means "no result" */
   1041    utm_alloc(extData->fromUTableUChars);
   1042    utm_alloc(extData->fromUTableValues);
   1043 
   1044    if(!generateFromUTrie(extData, table, fromUCount)) {
   1045        return false;
   1046    }
   1047 
   1048    /*
   1049     * offset the stage 1 trie entries by stage1Top because they will
   1050     * be stored in a single array
   1051     */
   1052    stage1=extData->stage1;
   1053    stage1Top=extData->stage1Top;
   1054    for(i=0; i<stage1Top; ++i) {
   1055        stage1[i]=(uint16_t)(stage1[i]+stage1Top);
   1056    }
   1057 
   1058    return true;
   1059 }
   1060 
   1061 /* -------------------------------------------------------------------------- */
   1062 
   1063 static UBool
   1064 CnvExtAddTable(NewConverter *cnvData, UCMTable *table, UConverterStaticData *staticData) {
   1065    CnvExtData *extData;
   1066 
   1067    if(table->unicodeMask&UCNV_HAS_SURROGATES) {
   1068        fprintf(stderr, "error: contains mappings for surrogate code points\n");
   1069        return false;
   1070    }
   1071 
   1072    staticData->conversionType=UCNV_MBCS;
   1073 
   1074    extData=(CnvExtData *)cnvData;
   1075 
   1076    /*
   1077     * assume that the table is sorted
   1078     *
   1079     * call the functions in this order because
   1080     * makeToUTable() modifies the original reverseMap,
   1081     * makeFromUTable() writes a whole new mapping into reverseMap
   1082     */
   1083    return
   1084        makeToUTable(extData, table) &&
   1085        makeFromUTable(extData, table);
   1086 }