icuSources/common/ucmndata.cpp

   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) 1999-2011, International Business Machines
   7 *   Corporation and others.  All Rights Reserved.
   8 *
   9 ******************************************************************************/
  10
  11
  12 /*------------------------------------------------------------------------------
  13  *
  14  *   UCommonData   An abstract interface for dealing with ICU Common Data Files.
  15  *                 ICU Common Data Files are a grouping of a number of individual
  16  *                 data items (resources, converters, tables, anything) into a
  17  *                 single file or dll.  The combined format includes a table of
  18  *                 contents for locating the individual items by name.
  19  *
  20  *                 Two formats for the table of contents are supported, which is
  21  *                 why there is an abstract inteface involved.
  22  *
  23  */
  24
  25 #include "unicode/utypes.h"
  26 #include "unicode/udata.h"
  27 #include "cstring.h"
  28 #include "ucmndata.h"
  29 #include "udatamem.h"
  30
  31 #if defined(UDATA_DEBUG) || defined(UDATA_DEBUG_DUMP)
  32 #   include <stdio.h>
  33 #endif
  34
  35 U_CFUNC uint16_t
  36 udata_getHeaderSize(const DataHeader *udh) {
  37     if(udh==NULL) {
  38         return 0;
  39     } else if(udh->info.isBigEndian==U_IS_BIG_ENDIAN) {
  40         /* same endianness */
  41         return udh->dataHeader.headerSize;
  42     } else {
  43         /* opposite endianness */
  44         uint16_t x=udh->dataHeader.headerSize;
  45         return (uint16_t)((x<<8)|(x>>8));
  46     }
  47 }
  48
  49 U_CFUNC uint16_t
  50 udata_getInfoSize(const UDataInfo *info) {
  51     if(info==NULL) {
  52         return 0;
  53     } else if(info->isBigEndian==U_IS_BIG_ENDIAN) {
  54         /* same endianness */
  55         return info->size;
  56     } else {
  57         /* opposite endianness */
  58         uint16_t x=info->size;
  59         return (uint16_t)((x<<8)|(x>>8));
  60     }
  61 }
  62
  63 /*-----------------------------------------------------------------------------*
  64  *                                                                             *
  65  *  Pointer TOCs.   TODO: This form of table-of-contents should be removed     *
  66  *                  because DLLs must be relocated on loading to correct the   *
  67  *                  pointer values and this operation makes shared memory      *
  68  *                  mapping of the data much less likely to work.              *
  69  *                                                                             *
  70  *-----------------------------------------------------------------------------*/
  71 typedef struct {
  72     const char       *entryName;
  73     const DataHeader *pHeader;
  74 } PointerTOCEntry;
  75
  76
  77 typedef struct  {
  78     uint32_t          count;
  79     uint32_t          reserved;
  80     PointerTOCEntry   entry[2];   /* Actual size is from count. */
  81 }  PointerTOC;
  82
  83
  84 /* definition of OffsetTOC struct types moved to ucmndata.h */
  85
  86 /*-----------------------------------------------------------------------------*
  87  *                                                                             *
  88  *    entry point lookup implementations                                       *
  89  *                                                                             *
  90  *-----------------------------------------------------------------------------*/
  91
  92 #ifndef MIN
  93 #define MIN(a,b) (((a)<(b)) ? (a) : (b))
  94 #endif
  95
  96 /**
  97  * Compare strings where we know the shared prefix length,
  98  * and advance the prefix length as we find that the strings share even more characters.
  99  */
 100 static int32_t
 101 strcmpAfterPrefix(const char *s1, const char *s2, int32_t *pPrefixLength) {
 102     int32_t pl=*pPrefixLength;
 103     int32_t cmp=0;
 104     s1+=pl;
 105     s2+=pl;
 106     for(;;) {
 107         int32_t c1=(uint8_t)*s1++;
 108         int32_t c2=(uint8_t)*s2++;
 109         cmp=c1-c2;
 110         if(cmp!=0 || c1==0) {  /* different or done */
 111             break;
 112         }
 113         ++pl;  /* increment shared same-prefix length */
 114     }
 115     *pPrefixLength=pl;
 116     return cmp;
 117 }
 118
 119 static int32_t
 120 offsetTOCPrefixBinarySearch(const char *s, const char *names,
 121                             const UDataOffsetTOCEntry *toc, int32_t count) {
 122     int32_t start=0;
 123     int32_t limit=count;
 124     /*
 125      * Remember the shared prefix between s, start and limit,
 126      * and don't compare that shared prefix again.
 127      * The shared prefix should get longer as we narrow the [start, limit[ range.
 128      */
 129     int32_t startPrefixLength=0;
 130     int32_t limitPrefixLength=0;
 131     if(count==0) {
 132         return -1;
 133     }
 134     /*
 135      * Prime the prefix lengths so that we don't keep prefixLength at 0 until
 136      * both the start and limit indexes have moved.
 137      * At the same time, we find if s is one of the start and (limit-1) names,
 138      * and if not, exclude them from the actual binary search.
 139      */
 140     if(0==strcmpAfterPrefix(s, names+toc[0].nameOffset, &startPrefixLength)) {
 141         return 0;
 142     }
 143     ++start;
 144     --limit;
 145     if(0==strcmpAfterPrefix(s, names+toc[limit].nameOffset, &limitPrefixLength)) {
 146         return limit;
 147     }
 148     while(start<limit) {
 149         int32_t i=(start+limit)/2;
 150         int32_t prefixLength=MIN(startPrefixLength, limitPrefixLength);
 151         int32_t cmp=strcmpAfterPrefix(s, names+toc[i].nameOffset, &prefixLength);
 152         if(cmp<0) {
 153             limit=i;
 154             limitPrefixLength=prefixLength;
 155         } else if(cmp==0) {
 156             return i;
 157         } else {
 158             start=i+1;
 159             startPrefixLength=prefixLength;
 160         }
 161     }
 162     return -1;
 163 }
 164
 165 static int32_t
 166 pointerTOCPrefixBinarySearch(const char *s, const PointerTOCEntry *toc, int32_t count) {
 167     int32_t start=0;
 168     int32_t limit=count;
 169     /*
 170      * Remember the shared prefix between s, start and limit,
 171      * and don't compare that shared prefix again.
 172      * The shared prefix should get longer as we narrow the [start, limit[ range.
 173      */
 174     int32_t startPrefixLength=0;
 175     int32_t limitPrefixLength=0;
 176     if(count==0) {
 177         return -1;
 178     }
 179     /*
 180      * Prime the prefix lengths so that we don't keep prefixLength at 0 until
 181      * both the start and limit indexes have moved.
 182      * At the same time, we find if s is one of the start and (limit-1) names,
 183      * and if not, exclude them from the actual binary search.
 184      */
 185     if(0==strcmpAfterPrefix(s, toc[0].entryName, &startPrefixLength)) {
 186         return 0;
 187     }
 188     ++start;
 189     --limit;
 190     if(0==strcmpAfterPrefix(s, toc[limit].entryName, &limitPrefixLength)) {
 191         return limit;
 192     }
 193     while(start<limit) {
 194         int32_t i=(start+limit)/2;
 195         int32_t prefixLength=MIN(startPrefixLength, limitPrefixLength);
 196         int32_t cmp=strcmpAfterPrefix(s, toc[i].entryName, &prefixLength);
 197         if(cmp<0) {
 198             limit=i;
 199             limitPrefixLength=prefixLength;
 200         } else if(cmp==0) {
 201             return i;
 202         } else {
 203             start=i+1;
 204             startPrefixLength=prefixLength;
 205         }
 206     }
 207     return -1;
 208 }
 209
 210 U_CDECL_BEGIN
 211 static uint32_t U_CALLCONV
 212 offsetTOCEntryCount(const UDataMemory *pData) {
 213     int32_t          retVal=0;
 214     const UDataOffsetTOC *toc = (UDataOffsetTOC *)pData->toc;
 215     if (toc != NULL) {
 216         retVal = toc->count;
 217     }
 218     return retVal;
 219 }
 220
 221 static const DataHeader * U_CALLCONV
 222 offsetTOCLookupFn(const UDataMemory *pData,
 223                   const char *tocEntryName,
 224                   int32_t *pLength,
 225                   UErrorCode *pErrorCode) {
 226     (void)pErrorCode;
 227     const UDataOffsetTOC  *toc = (UDataOffsetTOC *)pData->toc;
 228     if(toc!=NULL) {
 229         const char *base=(const char *)toc;
 230         int32_t number, count=(int32_t)toc->count;
 231
 232         /* perform a binary search for the data in the common data's table of contents */
 233 #if defined (UDATA_DEBUG_DUMP)
 234         /* list the contents of the TOC each time .. not recommended */
 235         for(number=0; number<count; ++number) {
 236             fprintf(stderr, "\tx%d: %s\n", number, &base[toc->entry[number].nameOffset]);
 237         }
 238 #endif
 239         number=offsetTOCPrefixBinarySearch(tocEntryName, base, toc->entry, count);
 240         if(number>=0) {
 241             /* found it */
 242             const UDataOffsetTOCEntry *entry=toc->entry+number;
 243 #ifdef UDATA_DEBUG
 244             fprintf(stderr, "%s: Found.\n", tocEntryName);
 245 #endif
 246             if((number+1) < count) {
 247                 *pLength = (int32_t)(entry[1].dataOffset - entry->dataOffset);
 248             } else {
 249                 *pLength = -1;
 250             }
 251             return (const DataHeader *)(base+entry->dataOffset);
 252         } else {
 253 #ifdef UDATA_DEBUG
 254             fprintf(stderr, "%s: Not found.\n", tocEntryName);
 255 #endif
 256             return NULL;
 257         }
 258     } else {
 259 #ifdef UDATA_DEBUG
 260         fprintf(stderr, "returning header\n");
 261 #endif
 262
 263         return pData->pHeader;
 264     }
 265 }
 266
 267
 268 static uint32_t U_CALLCONV pointerTOCEntryCount(const UDataMemory *pData) {
 269     const PointerTOC *toc = (PointerTOC *)pData->toc;
 270     return (uint32_t)((toc != NULL) ? (toc->count) : 0);
 271 }
 272
 273 static const DataHeader * U_CALLCONV pointerTOCLookupFn(const UDataMemory *pData,
 274                    const char *name,
 275                    int32_t *pLength,
 276                    UErrorCode *pErrorCode) {
 277     (void)pErrorCode;
 278     if(pData->toc!=NULL) {
 279         const PointerTOC *toc = (PointerTOC *)pData->toc;
 280         int32_t number, count=(int32_t)toc->count;
 281
 282 #if defined (UDATA_DEBUG_DUMP)
 283         /* list the contents of the TOC each time .. not recommended */
 284         for(number=0; number<count; ++number) {
 285             fprintf(stderr, "\tx%d: %s\n", number, toc->entry[number].entryName);
 286         }
 287 #endif
 288         number=pointerTOCPrefixBinarySearch(name, toc->entry, count);
 289         if(number>=0) {
 290             /* found it */
 291 #ifdef UDATA_DEBUG
 292             fprintf(stderr, "%s: Found.\n", toc->entry[number].entryName);
 293 #endif
 294             *pLength=-1;
 295             return UDataMemory_normalizeDataPointer(toc->entry[number].pHeader);
 296         } else {
 297 #ifdef UDATA_DEBUG
 298             fprintf(stderr, "%s: Not found.\n", name);
 299 #endif
 300             return NULL;
 301         }
 302     } else {
 303         return pData->pHeader;
 304     }
 305 }
 306 U_CDECL_END
 307
 308
 309 static const commonDataFuncs CmnDFuncs = {offsetTOCLookupFn,  offsetTOCEntryCount};
 310 static const commonDataFuncs ToCPFuncs = {pointerTOCLookupFn, pointerTOCEntryCount};
 311
 312
 313
 314 /*----------------------------------------------------------------------*
 315  *                                                                      *
 316  *  checkCommonData   Validate the format of a common data file.        *
 317  *                    Fill in the virtual function ptr based on TOC type *
 318  *                    If the data is invalid, close the UDataMemory     *
 319  *                    and set the appropriate error code.               *
 320  *                                                                      *
 321  *----------------------------------------------------------------------*/
 322 U_CFUNC void udata_checkCommonData(UDataMemory *udm, UErrorCode *err) {
 323     if (U_FAILURE(*err)) {
 324         return;
 325     }
 326
 327     if(udm==NULL || udm->pHeader==NULL) {
 328       *err=U_INVALID_FORMAT_ERROR;
 329     } else if(!(udm->pHeader->dataHeader.magic1==0xda &&
 330         udm->pHeader->dataHeader.magic2==0x27 &&
 331         udm->pHeader->info.isBigEndian==U_IS_BIG_ENDIAN &&
 332         udm->pHeader->info.charsetFamily==U_CHARSET_FAMILY)
 333         ) {
 334         /* header not valid */
 335         *err=U_INVALID_FORMAT_ERROR;
 336     }
 337     else if (udm->pHeader->info.dataFormat[0]==0x43 &&
 338         udm->pHeader->info.dataFormat[1]==0x6d &&
 339         udm->pHeader->info.dataFormat[2]==0x6e &&
 340         udm->pHeader->info.dataFormat[3]==0x44 &&
 341         udm->pHeader->info.formatVersion[0]==1
 342         ) {
 343         /* dataFormat="CmnD" */
 344         udm->vFuncs = &CmnDFuncs;
 345         udm->toc=(const char *)udm->pHeader+udata_getHeaderSize(udm->pHeader);
 346     }
 347     else if(udm->pHeader->info.dataFormat[0]==0x54 &&
 348         udm->pHeader->info.dataFormat[1]==0x6f &&
 349         udm->pHeader->info.dataFormat[2]==0x43 &&
 350         udm->pHeader->info.dataFormat[3]==0x50 &&
 351         udm->pHeader->info.formatVersion[0]==1
 352         ) {
 353         /* dataFormat="ToCP" */
 354         udm->vFuncs = &ToCPFuncs;
 355         udm->toc=(const char *)udm->pHeader+udata_getHeaderSize(udm->pHeader);
 356     }
 357     else {
 358         /* dataFormat not recognized */
 359         *err=U_INVALID_FORMAT_ERROR;
 360     }
 361
 362     if (U_FAILURE(*err)) {
 363         /* If the data is no good and we memory-mapped it ourselves,
 364          *  close the memory mapping so it doesn't leak.  Note that this has
 365          *  no effect on non-memory mapped data, other than clearing fields in udm.
 366          */
 367         udata_close(udm);
 368     }
 369 }
 370
 371 /*
 372  * TODO: Add a udata_swapPackageHeader() function that swaps an ICU .dat package
 373  * header but not its sub-items.
 374  * This function will be needed for automatic runtime swapping.
 375  * Sub-items should not be swapped to limit the swapping to the parts of the
 376  * package that are actually used.
 377  *
 378  * Since lengths of items are implicit in the order and offsets of their
 379  * ToC entries, and since offsets are relative to the start of the ToC,
 380  * a swapped version may need to generate a different data structure
 381  * with pointers to the original data items and with their lengths
 382  * (-1 for the last one if it is not known), and maybe even pointers to the
 383  * swapped versions of the items.
 384  * These pointers to swapped versions would establish a cache;
 385  * instead, each open data item could simply own the storage for its swapped
 386  * data. This fits better with the current design.
 387  *
 388  * markus 2003sep18 Jitterbug 2235
 389  */