text: /*
  ******************************************************************************
  *
  *   Copyright (C) 1999-2010, International Business Machines
  *   Corporation and others.  All Rights Reserved.
  *
  ******************************************************************************
  *   file name:  udata.cpp
  *   encoding:   US-ASCII
  *   tab size:   8 (not used)
  *   indentation:4
  *
  *   created on: 1999oct25
  *   created by: Markus W. Scherer
  */
  
  #include "unicode/utypes.h"  /* U_LINUX */
  
  #ifdef U_LINUX
  /* if gcc
  #define ATTRIBUTE_WEAK __attribute__ ((weak))
  might have to #include some other header
  */
  #endif
  
  #include "unicode/putil.h"
  #include "unicode/udata.h"
  #include "unicode/uversion.h"
  #include "charstr.h"
  #include "cmemory.h"
  #include "cstring.h"
  #include "putilimp.h"
  #include "ucln_cmn.h"
  #include "ucmndata.h"
  #include "udatamem.h"
  #include "uhash.h"
  #include "umapfile.h"
  #include "umutex.h"
  
  /***********************************************************************
  *
  *   Notes on the organization of the ICU data implementation
  *
  *      All of the public API is defined in udata.h
  *
  *      The implementation is split into several files...
  *
  *         - udata.c  (this file) contains higher level code that knows about
  *                     the search paths for locating data, caching opened data, etc.
  *
  *         - umapfile.c  contains the low level platform-specific code for actually loading
  *                     (memory mapping, file reading, whatever) data into memory.
  *
  *         - ucmndata.c  deals with the tables of contents of ICU data items within
  *                     an ICU common format data file.  The implementation includes
  *                     an abstract interface and support for multiple TOC formats.
  *                     All knowledge of any specific TOC format is encapsulated here.
  *
  *         - udatamem.c has code for managing UDataMemory structs.  These are little
  *                     descriptor objects for blocks of memory holding ICU data of
  *                     various types.
  */
  
  /* configuration ---------------------------------------------------------- */
  
  /* If you are excruciatingly bored turn this on .. */
  /* #define UDATA_DEBUG 1 */
  
  #if defined(UDATA_DEBUG)
  #   include <stdio.h>
  #endif
  
  #define LENGTHOF(array) (int32_t)(sizeof(array)/sizeof((array)[0]))
  
  U_NAMESPACE_USE
  
  /***********************************************************************
  *
  *    static (Global) data
  *
  ************************************************************************/
  
  /*
   * Pointers to the common ICU data.
   *
   * We store multiple pointers to ICU data packages and iterate through them
   * when looking for a data item.
   *
   * It is possible to combine this with dependency inversion:
   * One or more data package libraries may export
   * functions that each return a pointer to their piece of the ICU data,
   * and this file would import them as weak functions, without a
   * strong linker dependency from the common library on the data library.
   *
   * Then we can have applications depend on only that part of ICU's data
   * that they really need, reducing the size of binaries that take advantage
   * of this.
   */
  static UDataMemory *gCommonICUDataArray[10] = { NULL };
  
  static UBool gHaveTriedToLoadCommonData = FALSE;  /* See extendICUData(). */
  
  static UHashtable  *gCommonDataCache = NULL;  /* Global hash table of opened ICU data files.  */
  
  static UDataFileAccess  gDataFileAccess = UDATA_DEFAULT_ACCESS;
  
  static UBool U_CALLCONV
  udata_cleanup(void)
  {
      int32_t i;
  
      if (gCommonDataCache) {             /* Delete the cache of user data mappings.  */
          uhash_close(gCommonDataCache);  /*   Table owns the contents, and will delete them. */
          gCommonDataCache = NULL;        /*   Cleanup is not thread safe.                */
      }
  
      for (i = 0; i < LENGTHOF(gCommonICUDataArray) && gCommonICUDataArray[i] != NULL; ++i) {
          udata_close(gCommonICUDataArray[i]);
          gCommonICUDataArray[i] = NULL;
      }
      gHaveTriedToLoadCommonData = FALSE;
  
      return TRUE;                   /* Everything was cleaned up */
  }
  
  
  
  
  /*
   * setCommonICUData.   Set a UDataMemory to be the global ICU Data
   */
  static UBool
  setCommonICUData(UDataMemory *pData,     /*  The new common data.  Belongs to caller, we copy it. */
                   UBool       warn,       /*  If true, set USING_DEFAULT warning if ICUData was    */
                                           /*    changed by another thread before we got to it.     */
                   UErrorCode *pErr)
  {
      UDataMemory  *newCommonData = UDataMemory_createNewInstance(pErr);
      int32_t i;
      UBool didUpdate = FALSE;
      if (U_FAILURE(*pErr)) {
          return FALSE;
      }
  
      /*  For the assignment, other threads must cleanly see either the old            */
      /*    or the new, not some partially initialized new.  The old can not be        */
      /*    deleted - someone may still have a pointer to it lying around in           */
      /*    their locals.                                                              */
      UDatamemory_assign(newCommonData, pData);
      umtx_lock(NULL);
      for (i = 0; i < LENGTHOF(gCommonICUDataArray); ++i) {
          if (gCommonICUDataArray[i] == NULL) {
              gCommonICUDataArray[i] = newCommonData;
              ucln_common_registerCleanup(UCLN_COMMON_UDATA, udata_cleanup);
              didUpdate = TRUE;
              break;
          } else if (gCommonICUDataArray[i]->pHeader == pData->pHeader) {
              /* The same data pointer is already in the array. */
              break;
          }
      }
      umtx_unlock(NULL);
  
      if (i == LENGTHOF(gCommonICUDataArray) && warn) {
          *pErr = U_USING_DEFAULT_WARNING;
      }
      if (!didUpdate) {
          uprv_free(newCommonData);
      }
      return didUpdate;
  }
  
  static UBool
  setCommonICUDataPointer(const void *pData, UBool /*warn*/, UErrorCode *pErrorCode) {
      UDataMemory tData;
      UDataMemory_init(&tData);
      tData.pHeader = (const DataHeader *)pData;
      udata_checkCommonData(&tData, pErrorCode);
      return setCommonICUData(&tData, FALSE, pErrorCode);
  }
  
  static const char *
  findBasename(const char *path) {
      const char *basename=uprv_strrchr(path, U_FILE_SEP_CHAR);
      if(basename==NULL) {
          return path;
      } else {
          return basename+1;
      }
  }
  
  #ifdef UDATA_DEBUG
  static const char *
  packageNameFromPath(const char *path)
  {
      if((path == NULL) || (*path == 0)) {
          return U_ICUDATA_NAME;
      }
  
      path = findBasename(path);
  
      if((path == NULL) || (*path == 0)) {
          return U_ICUDATA_NAME;
      }
  
      return path;
  }
  #endif
  
  /*----------------------------------------------------------------------*
   *                                                                      *
   *   Cache for common data                                              *
   *      Functions for looking up or adding entries to a cache of        *
   *      data that has been previously opened.  Avoids a potentially     *
   *      expensive operation of re-opening the data for subsequent       *
   *      uses.                                                           *
   *                                                                      *
   *      Data remains cached for the duration of the process.            *
   *                                                                      *
   *----------------------------------------------------------------------*/
  
  typedef struct DataCacheElement {
      char          *name;
      UDataMemory   *item;
  } DataCacheElement;
  
  
  
  /*
   * Deleter function for DataCacheElements.
   *         udata cleanup function closes the hash table; hash table in turn calls back to
   *         here for each entry.
   */
  static void U_CALLCONV DataCacheElement_deleter(void *pDCEl) {
      DataCacheElement *p = (DataCacheElement *)pDCEl;
      udata_close(p->item);              /* unmaps storage */
      uprv_free(p->name);                /* delete the hash key string. */
      uprv_free(pDCEl);                  /* delete 'this'          */
  }
  
   /*   udata_getCacheHashTable()
   *     Get the hash table used to store the data cache entries.
   *     Lazy create it if it doesn't yet exist.
   */
  static UHashtable *udata_getHashTable() {
      UErrorCode   err = U_ZERO_ERROR;
      UBool        cacheIsInitialized;
      UHashtable  *tHT = NULL;
  
      UMTX_CHECK(NULL, (gCommonDataCache != NULL), cacheIsInitialized);
  
      if (cacheIsInitialized) {
          return gCommonDataCache;
      }
  
      tHT = uhash_open(uhash_hashChars, uhash_compareChars, NULL, &err);
      /* Check for null pointer. */
      if (tHT == NULL) {
      	return NULL; /* TODO:  Handle this error better. */
      }
      uhash_setValueDeleter(tHT, DataCacheElement_deleter);
  
      umtx_lock(NULL);
      if (gCommonDataCache == NULL) {
          gCommonDataCache = tHT;
          tHT = NULL;
          ucln_common_registerCleanup(UCLN_COMMON_UDATA, udata_cleanup);
      }
      umtx_unlock(NULL);
      if (tHT != NULL) {
          uhash_close(tHT);
      }
  
      if (U_FAILURE(err)) {
          return NULL;      /* TODO:  handle this error better.  */
      }
      return gCommonDataCache;
  }
  
  
  
  static UDataMemory *udata_findCachedData(const char *path)
  {
      UHashtable        *htable;
      UDataMemory       *retVal = NULL;
      DataCacheElement  *el;
      const char        *baseName;
  
      baseName = findBasename(path);   /* Cache remembers only the base name, not the full path. */
      htable = udata_getHashTable();
      umtx_lock(NULL);
      el = (DataCacheElement *)uhash_get(htable, baseName);
      umtx_unlock(NULL);
      if (el != NULL) {
          retVal = el->item;
      }
  #ifdef UDATA_DEBUG
      fprintf(stderr, "Cache: [%s] -> %p\n", baseName, retVal);
  #endif
      return retVal;
  }
  
  
  static UDataMemory *udata_cacheDataItem(const char *path, UDataMemory *item, UErrorCode *pErr) {
      DataCacheElement *newElement;
      const char       *baseName;
      int32_t           nameLen;
      UHashtable       *htable;
      DataCacheElement *oldValue = NULL;
      UErrorCode        subErr = U_ZERO_ERROR;
  
      if (U_FAILURE(*pErr)) {
          return NULL;
      }
  
      /* Create a new DataCacheElement - the thingy we store in the hash table -
       * and copy the supplied path and UDataMemoryItems into it.
       */
      newElement = (DataCacheElement *)uprv_malloc(sizeof(DataCacheElement));
      if (newElement == NULL) {
          *pErr = U_MEMORY_ALLOCATION_ERROR;
          return NULL;
      }
      newElement->item = UDataMemory_createNewInstance(pErr);
      if (U_FAILURE(*pErr)) {
          uprv_free(newElement);
          return NULL;
      }
      UDatamemory_assign(newElement->item, item);
  
      baseName = findBasename(path);
      nameLen = (int32_t)uprv_strlen(baseName);
      newElement->name = (char *)uprv_malloc(nameLen+1);
      if (newElement->name == NULL) {
          *pErr = U_MEMORY_ALLOCATION_ERROR;
          uprv_free(newElement->item);
          uprv_free(newElement);
          return NULL;
      }
      uprv_strcpy(newElement->name, baseName);
  
      /* Stick the new DataCacheElement into the hash table.
      */
      htable = udata_getHashTable();
      umtx_lock(NULL);
      oldValue = (DataCacheElement *)uhash_get(htable, path);
      if (oldValue != NULL) {
          subErr = U_USING_DEFAULT_WARNING;
      }
      else {
          uhash_put(
              htable,
              newElement->name,               /* Key   */
              newElement,                     /* Value */
              &subErr);
      }
      umtx_unlock(NULL);
  
  #ifdef UDATA_DEBUG
      fprintf(stderr, "Cache: [%s] <<< %p : %s. vFunc=%p\n", newElement->name, 
      newElement->item, u_errorName(subErr), newElement->item->vFuncs);
  #endif
  
      if (subErr == U_USING_DEFAULT_WARNING || U_FAILURE(subErr)) {
          *pErr = subErr; /* copy sub err unto fillin ONLY if something happens. */
          uprv_free(newElement->name);
          uprv_free(newElement->item);
          uprv_free(newElement);
          return oldValue ? oldValue->item : NULL;
      }
  
      return newElement->item;
  }
  
  /*----------------------------------------------------------------------*==============
   *                                                                      *
   *  Path management.  Could be shared with other tools/etc if need be   *
   * later on.                                                            *
   *                                                                      *
   *----------------------------------------------------------------------*/
  
  #define U_DATA_PATHITER_BUFSIZ  128        /* Size of local buffer for paths         */
                                             /*   Overflow causes malloc of larger buf */
  
  U_NAMESPACE_BEGIN
  
  class UDataPathIterator
  {
  public:
      UDataPathIterator(const char *path, const char *pkg,
                        const char *item, const char *suffix, UBool doCheckLastFour,
                        UErrorCode *pErrorCode);
      const char *next(UErrorCode *pErrorCode);
  
  private:
      const char *path;                              /* working path (u_icudata_Dir) */
      const char *nextPath;                          /* path following this one */
      const char *basename;                          /* item's basename (icudt22e_mt.res)*/
      const char *suffix;                            /* item suffix (can be null) */
  
      uint32_t    basenameLen;                       /* length of basename */
  
      CharString  itemPath;                          /* path passed in with item name */
      CharString  pathBuffer;                        /* output path for this it'ion */
      CharString  packageStub;                       /* example:  "/icudt28b". Will ignore that leaf in set paths. */
  
      UBool       checkLastFour;                     /* if TRUE then allow paths such as '/foo/myapp.dat'
                                                      * to match, checks last 4 chars of suffix with
                                                      * last 4 of path, then previous chars. */
  };
  
  /**
   * @param iter  The iterator to be initialized. Its current state does not matter. 
   * @param path  The full pathname to be iterated over.  If NULL, defaults to U_ICUDATA_NAME 
   * @param pkg   Package which is being searched for, ex "icudt28l".  Will ignore leave directories such as /icudt28l 
   * @param item  Item to be searched for.  Can include full path, such as /a/b/foo.dat 
   * @param suffix  Optional item suffix, if not-null (ex. ".dat") then 'path' can contain 'item' explicitly.
   *               Ex:   'stuff.dat' would be found in '/a/foo:/tmp/stuff.dat:/bar/baz' as item #2.   
   *                     '/blarg/stuff.dat' would also be found.
   */
  UDataPathIterator::UDataPathIterator(const char *inPath, const char *pkg,
                                       const char *item, const char *inSuffix, UBool doCheckLastFour,
                                       UErrorCode *pErrorCode)
  {
  #ifdef UDATA_DEBUG
          fprintf(stderr, "SUFFIX1=%s PATH=%s\n", inSuffix, inPath);
  #endif
      /** Path **/
      if(inPath == NULL) {
          path = u_getDataDirectory();
      } else {
          path = inPath;
      }
  
      /** Package **/
      if(pkg != NULL) {
        packageStub.append(U_FILE_SEP_CHAR, *pErrorCode).append(pkg, *pErrorCode);
  #ifdef UDATA_DEBUG
        fprintf(stderr, "STUB=%s [%d]\n", packageStub.data(), packageStub.length());
  #endif
      }
  
      /** Item **/
      basename = findBasename(item);
      basenameLen = (int32_t)uprv_strlen(basename);
  
      /** Item path **/
      if(basename == item) {
          nextPath = path;
      } else {
          itemPath.append(item, (int32_t)(basename-item), *pErrorCode);
          nextPath = itemPath.data();
      }
  #ifdef UDATA_DEBUG
      fprintf(stderr, "SUFFIX=%s [%p]\n", inSuffix, inSuffix);
  #endif
  
      /** Suffix  **/
      if(inSuffix != NULL) {
          suffix = inSuffix;
      } else {
          suffix = "";
      }
  
      checkLastFour = doCheckLastFour;
  
      /* pathBuffer will hold the output path strings returned by this iterator */
  
  #ifdef UDATA_DEBUG
      fprintf(stderr, "%p: init %s -> [path=%s], [base=%s], [suff=%s], [itempath=%s], [nextpath=%s], [checklast4=%s]\n",
              iter,
              item,
              path,
              basename,
              suffix,
              itemPath.data(),
              nextPath,
              checkLastFour?"TRUE":"false");
  #endif
  }
  
  /**
   * Get the next path on the list.
   *
   * @param iter The Iter to be used 
   * @param len  If set, pointer to the length of the returned path, for convenience. 
   * @return Pointer to the next path segment, or NULL if there are no more.
   */
  const char *UDataPathIterator::next(UErrorCode *pErrorCode)
  {
      if(U_FAILURE(*pErrorCode)) {
          return NULL;
      }
  
      const char *currentPath = NULL;
      int32_t     pathLen = 0;
      const char *pathBasename;
  
      do
      {
          if( nextPath == NULL ) {
              break;
          }
          currentPath = nextPath;
  
          if(nextPath == itemPath.data()) { /* we were processing item's path. */
              nextPath = path; /* start with regular path next tm. */
              pathLen = (int32_t)uprv_strlen(currentPath);
          } else {
              /* fix up next for next time */
              nextPath = uprv_strchr(currentPath, U_PATH_SEP_CHAR);
              if(nextPath == NULL) {
                  /* segment: entire path */
                  pathLen = (int32_t)uprv_strlen(currentPath); 
              } else {
                  /* segment: until next segment */
                  pathLen = (int32_t)(nextPath - currentPath);
                  /* skip divider */
                  nextPath ++;
              }
          }
  
          if(pathLen == 0) {
              continue;
          }
  
  #ifdef UDATA_DEBUG
          fprintf(stderr, "rest of path (IDD) = %s\n", currentPath);
          fprintf(stderr, "                     ");
          { 
              uint32_t qqq;
              for(qqq=0;qqq<pathLen;qqq++)
              {
                  fprintf(stderr, " ");
              }
  
              fprintf(stderr, "^\n");
          }
  #endif
          pathBuffer.clear().append(currentPath, pathLen, *pErrorCode);
  
          /* check for .dat files */
          pathBasename = findBasename(pathBuffer.data());
  
          if(checkLastFour == TRUE && 
             (pathLen>=4) &&
             uprv_strncmp(pathBuffer.data() +(pathLen-4), suffix, 4)==0 && /* suffix matches */
             uprv_strncmp(findBasename(pathBuffer.data()), basename, basenameLen)==0  && /* base matches */
             uprv_strlen(pathBasename)==(basenameLen+4)) { /* base+suffix = full len */
  
  #ifdef UDATA_DEBUG
              fprintf(stderr, "Have %s file on the path: %s\n", suffix, pathBuffer.data());
  #endif
              /* do nothing */
          }
          else 
          {       /* regular dir path */
              if(pathBuffer[pathLen-1] != U_FILE_SEP_CHAR) {
                  if((pathLen>=4) &&
                     uprv_strncmp(pathBuffer.data()+(pathLen-4), ".dat", 4) == 0)
                  {
  #ifdef UDATA_DEBUG
                      fprintf(stderr, "skipping non-directory .dat file %s\n", pathBuffer.data());
  #endif
                      continue;
                  }
  
                  /* Check if it is a directory with the same name as our package */
                  if(!packageStub.isEmpty() &&
                     (pathLen > packageStub.length()) &&
                     !uprv_strcmp(pathBuffer.data() + pathLen - packageStub.length(), packageStub.data())) {
  #ifdef UDATA_DEBUG
                    fprintf(stderr, "Found stub %s (will add package %s of len %d)\n", packageStub.data(), basename, basenameLen);
  #endif
                    pathBuffer.truncate(pathLen - packageStub.length());
                  }
                  pathBuffer.append(U_FILE_SEP_CHAR, *pErrorCode);
              }
  
              /* + basename */
              pathBuffer.append(packageStub.data()+1, packageStub.length()-1, *pErrorCode);
  
              if(*suffix)  /* tack on suffix */
              {
                  pathBuffer.append(suffix, *pErrorCode);
              }
          }
  
  #ifdef UDATA_DEBUG
          fprintf(stderr, " -->  %s\n", pathBuffer.data());
  #endif
  
          return pathBuffer.data();
  
      } while(path);
  
      /* fell way off the end */
      return NULL;
  }
  
  U_NAMESPACE_END
  
  /* ==================================================================================*/
  
  
  /*----------------------------------------------------------------------*
   *                                                                      *
   *  Add a static reference to the common data  library                  *
   *   Unless overridden by an explicit udata_setCommonData, this will be *
   *      our common data.                                                *
   *                                                                      *
   *----------------------------------------------------------------------*/
  extern "C" const DataHeader U_DATA_API U_ICUDATA_ENTRY_POINT;
  
  /*
   * This would be a good place for weak-linkage declarations of
   * partial-data-library access functions where each returns a pointer
   * to its data package, if it is linked in.
   */
  /*
  extern const void *uprv_getICUData_collation(void) ATTRIBUTE_WEAK;
  extern const void *uprv_getICUData_conversion(void) ATTRIBUTE_WEAK;
  */
  
  /*----------------------------------------------------------------------*
   *                                                                      *
   *   openCommonData   Attempt to open a common format (.dat) file       *
   *                    Map it into memory (if it's not there already)    *
   *                    and return a UDataMemory object for it.           *
   *                                                                      *
   *                    If the requested data is already open and cached  *
   *                       just return the cached UDataMem object.        *
   *                                                                      *
   *----------------------------------------------------------------------*/
  static UDataMemory *
  openCommonData(const char *path,          /*  Path from OpenChoice?          */
                 int32_t commonDataIndex,   /*  ICU Data (index >= 0) if path == NULL */
                 UErrorCode *pErrorCode)
  {
      UDataMemory tData;
      const char *pathBuffer;
      const char *inBasename;
  
      if (U_FAILURE(*pErrorCode)) {
          return NULL;
      }
  
      UDataMemory_init(&tData);
  
      /* ??????? TODO revisit this */ 
      if (commonDataIndex >= 0) {
          /* "mini-cache" for common ICU data */
          if(commonDataIndex >= LENGTHOF(gCommonICUDataArray)) {
              return NULL;
          }
          if(gCommonICUDataArray[commonDataIndex] == NULL) {
              int32_t i;
              for(i = 0; i < commonDataIndex; ++i) {
                  if(gCommonICUDataArray[i]->pHeader == &U_ICUDATA_ENTRY_POINT) {
                      /* The linked-in data is already in the list. */
                      return NULL;
                  }
              }
  
              /* Add the linked-in data to the list. */
              /*
               * This is where we would check and call weakly linked partial-data-library
               * access functions.
               */
              /*
              if (uprv_getICUData_collation) {
                  setCommonICUDataPointer(uprv_getICUData_collation(), FALSE, pErrorCode);
              }
              if (uprv_getICUData_conversion) {
                  setCommonICUDataPointer(uprv_getICUData_conversion(), FALSE, pErrorCode);
              }
              */
              setCommonICUDataPointer(&U_ICUDATA_ENTRY_POINT, FALSE, pErrorCode);
          }
          return gCommonICUDataArray[commonDataIndex];
      }
  
  
      /* request is NOT for ICU Data.  */
  
      /* Find the base name portion of the supplied path.   */
      /*   inBasename will be left pointing somewhere within the original path string.      */
      inBasename = findBasename(path);
  #ifdef UDATA_DEBUG
      fprintf(stderr, "inBasename = %s\n", inBasename);
  #endif
  
      if(*inBasename==0) {
          /* no basename.     This will happen if the original path was a directory name,   */
          /*    like  "a/b/c/".   (Fallback to separate files will still work.)             */
  #ifdef UDATA_DEBUG
          fprintf(stderr, "ocd: no basename in %s, bailing.\n", path);
  #endif
          *pErrorCode=U_FILE_ACCESS_ERROR;
          return NULL;
      }
  
     /* Is the requested common data file already open and cached?                     */
     /*   Note that the cache is keyed by the base name only.  The rest of the path,   */
     /*     if any, is not considered.                                                 */
     {
          UDataMemory  *dataToReturn = udata_findCachedData(inBasename);
          if (dataToReturn != NULL) {
              return dataToReturn;
          }
      }
  
      /* Requested item is not in the cache.
       * Hunt it down, trying all the path locations
       */
  
      UDataPathIterator iter(u_getDataDirectory(), inBasename, path, ".dat", TRUE, pErrorCode);
  
      while((UDataMemory_isLoaded(&tData)==FALSE) && (pathBuffer = iter.next(pErrorCode)) != NULL)
      {
  #ifdef UDATA_DEBUG
          fprintf(stderr, "ocd: trying path %s - ", pathBuffer);
  #endif
          uprv_mapFile(&tData, pathBuffer);
  #ifdef UDATA_DEBUG
          fprintf(stderr, "%s\n", UDataMemory_isLoaded(&tData)?"LOADED":"not loaded");
  #endif
      }
  
  #if defined(OS390_STUBDATA) && defined(OS390BATCH)
      if (!UDataMemory_isLoaded(&tData)) {
          char ourPathBuffer[1024];
          /* One more chance, for extendCommonData() */
          uprv_strncpy(ourPathBuffer, path, 1019);
          ourPathBuffer[1019]=0;
          uprv_strcat(ourPathBuffer, ".dat");
          uprv_mapFile(&tData, ourPathBuffer);
      }
  #endif
  
      if (!UDataMemory_isLoaded(&tData)) {
          /* no common data */
          *pErrorCode=U_FILE_ACCESS_ERROR;
          return NULL;
      }
  
      /* we have mapped a file, check its header */
      udata_checkCommonData(&tData, pErrorCode);
  
  
      /* Cache the UDataMemory struct for this .dat file,
       *   so we won't need to hunt it down and map it again next time
       *   something is needed from it.                */
      return udata_cacheDataItem(inBasename, &tData, pErrorCode);
  }
  
  
  /*----------------------------------------------------------------------*
   *                                                                      *
   *   extendICUData   If the full set of ICU data was not loaded at      *
   *                   program startup, load it now.  This function will  *
   *                   be called when the lookup of an ICU data item in   *
   *                   the common ICU data fails.                         *
   *                                                                      *
   *                   return true if new data is loaded, false otherwise.*
   *                                                                      *
   *----------------------------------------------------------------------*/
  static UBool extendICUData(UErrorCode *pErr)
  {
      UDataMemory   *pData;
      UDataMemory   copyPData;
      UBool         didUpdate = FALSE;
  
      /*
       * There is a chance for a race condition here.
       * Normally, ICU data is loaded from a DLL or via mmap() and
       * setCommonICUData() will detect if the same address is set twice.
       * If ICU is built with data loading via fread() then the address will
       * be different each time the common data is loaded and we may add
       * multiple copies of the data.
       * In this case, use a mutex to prevent the race.
       * Use a specific mutex to avoid nested locks of the global mutex.
       */
  #if MAP_IMPLEMENTATION==MAP_STDIO
      static UMTX extendICUDataMutex = NULL;
      umtx_lock(&extendICUDataMutex);
  #endif
      if(!gHaveTriedToLoadCommonData) {
          gHaveTriedToLoadCommonData = TRUE;
  
          /* See if we can explicitly open a .dat file for the ICUData. */
          pData = openCommonData(
                     U_ICUDATA_NAME,            /*  "icudt20l" , for example.          */
                     -1,                        /*  Pretend we're not opening ICUData  */
                     pErr);
  
          /* How about if there is no pData, eh... */
  
         UDataMemory_init(&copyPData);
         if(pData != NULL) {
            UDatamemory_assign(&copyPData, pData);
            copyPData.map = 0;              /* The mapping for this data is owned by the hash table */
            copyPData.mapAddr = 0;          /*   which will unmap it when ICU is shut down.         */
                                            /* CommonICUData is also unmapped when ICU is shut down.*/
                                            /* To avoid unmapping the data twice, zero out the map  */
                                            /*   fields in the UDataMemory that we're assigning     */
                                            /*   to CommonICUData.                                  */
  
            didUpdate =
                setCommonICUData(&copyPData,/*  The new common data.                                */
                         FALSE,             /*  No warnings if write didn't happen                  */
                         pErr);             /*  setCommonICUData honors errors; NOP if error set    */
          }
      }
  #if MAP_IMPLEMENTATION==MAP_STDIO
      umtx_unlock(&extendICUDataMutex);
  #endif
      return didUpdate;               /* Return true if ICUData pointer was updated.   */
                                      /*   (Could potentialy have been done by another thread racing */
                                      /*   us through here, but that's fine, we still return true    */
                                      /*   so that current thread will also examine extended data.   */
  }
  
  /*----------------------------------------------------------------------*
   *                                                                      *
   *   udata_setCommonData                                                *
   *                                                                      *
   *----------------------------------------------------------------------*/
  U_CAPI void U_EXPORT2
  udata_setCommonData(const void *data, UErrorCode *pErrorCode) {
      UDataMemory dataMemory;
  
      if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
          return;
      }
  
      if(data==NULL) {
          *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
          return;
      }
  
      /* set the data pointer and test for validity */
      UDataMemory_init(&dataMemory);
      UDataMemory_setData(&dataMemory, data);
      udata_checkCommonData(&dataMemory, pErrorCode);
      if (U_FAILURE(*pErrorCode)) {return;}
  
      /* we have good data */
      /* Set it up as the ICU Common Data.  */
      setCommonICUData(&dataMemory, TRUE, pErrorCode);
  }
  
  /*---------------------------------------------------------------------------
   *
   *  udata_setAppData
   *
   *---------------------------------------------------------------------------- */
  U_CAPI void U_EXPORT2
  udata_setAppData(const char *path, const void *data, UErrorCode *err)
  {
      UDataMemory     udm;
  
      if(err==NULL || U_FAILURE(*err)) {
          return;
      }
      if(data==NULL) {
          *err=U_ILLEGAL_ARGUMENT_ERROR;
          return;
      }
  
      UDataMemory_init(&udm);
      UDataMemory_setData(&udm, data);
      udata_checkCommonData(&udm, err);
      udata_cacheDataItem(path, &udm, err);
  }
  
  /*----------------------------------------------------------------------------*
   *                                                                            *
   *  checkDataItem     Given a freshly located/loaded data item, either        *
   *                    an entry in a common file or a separately loaded file,  *
   *                    sanity check its header, and see if the data is         *
   *                    acceptable to the app.                                  *
   *                    If the data is good, create and return a UDataMemory    *
   *                    object that can be returned to the application.         *
   *                    Return NULL on any sort of failure.                     *
   *                                                                            *
   *----------------------------------------------------------------------------*/
  static UDataMemory *
  checkDataItem
  (
   const DataHeader         *pHeader,         /* The data item to be checked.                */
   UDataMemoryIsAcceptable  *isAcceptable,    /* App's call-back function                    */
   void                     *context,         /*   pass-thru param for above.                */
   const char               *type,            /*   pass-thru param for above.                */
   const char               *name,            /*   pass-thru param for above.                */
   UErrorCode               *nonFatalErr,     /* Error code if this data was not acceptable  */
                                              /*   but openChoice should continue with       */
                                              /*   trying to get data from fallback path.    */
   UErrorCode               *fatalErr         /* Bad error, caller should return immediately */
   )
  {
      UDataMemory  *rDataMem = NULL;          /* the new UDataMemory, to be returned.        */
  
      if (U_FAILURE(*fatalErr)) {
          return NULL;
      }
  
      if(pHeader->dataHeader.magic1==0xda &&
          pHeader->dataHeader.magic2==0x27 &&
          (isAcceptable==NULL || isAcceptable(context, type, name, &pHeader->info))
      ) {
          rDataMem=UDataMemory_createNewInstance(fatalErr);
          if (U_FAILURE(*fatalErr)) {
              return NULL;
          }
          rDataMem->pHeader = pHeader;
      } else {
          /* the data is not acceptable, look further */
          /* If we eventually find something good, this errorcode will be */
          /*    cleared out.                                              */
          *nonFatalErr=U_INVALID_FORMAT_ERROR;
      }
      return rDataMem;
  }
  
  /**
   * @return 0 if not loaded, 1 if loaded or err 
   */
  static UDataMemory *doLoadFromIndividualFiles(const char *pkgName, 
          const char *dataPath, const char *tocEntryPathSuffix,
              /* following arguments are the same as doOpenChoice itself */
              const char *path, const char *type, const char *name,
               UDataMemoryIsAcceptable *isAcceptable, void *context,
               UErrorCode *subErrorCode,
               UErrorCode *pErrorCode)
  {
      const char         *pathBuffer;
      UDataMemory         dataMemory;
      UDataMemory *pEntryData;
  
      /* look in ind. files: package\nam.typ  ========================= */
      /* init path iterator for individual files */
      UDataPathIterator iter(dataPath, pkgName, path, tocEntryPathSuffix, FALSE, pErrorCode);
  
      while((pathBuffer = iter.next(pErrorCode)))
      {
  #ifdef UDATA_DEBUG
          fprintf(stderr, "UDATA: trying individual file %s\n", pathBuffer);
  #endif
          if(uprv_mapFile(&dataMemory, pathBuffer))
          {
              pEntryData = checkDataItem(dataMemory.pHeader, isAcceptable, context, type, name, subErrorCode, pErrorCode);
              if (pEntryData != NULL) {
                  /* Data is good.
                  *  Hand off ownership of the backing memory to the user's UDataMemory.
                  *  and return it.   */
                  pEntryData->mapAddr = dataMemory.mapAddr;
                  pEntryData->map     = dataMemory.map;
  
  #ifdef UDATA_DEBUG
                  fprintf(stderr, "** Mapped file: %s\n", pathBuffer);
  #endif
                  return pEntryData;
              }
  
              /* the data is not acceptable, or some error occured.  Either way, unmap the memory */
              udata_close(&dataMemory);
  
              /* If we had a nasty error, bail out completely.  */
              if (U_FAILURE(*pErrorCode)) {
                  return NULL;
              }
  
              /* Otherwise remember that we found data but didn't like it for some reason  */
              *subErrorCode=U_INVALID_FORMAT_ERROR;
          }
  #ifdef UDATA_DEBUG
          fprintf(stderr, "%s\n", UDataMemory_isLoaded(&dataMemory)?"LOADED":"not loaded");
  #endif
      }
      return NULL;
  }
  
  /**
   * @return 0 if not loaded, 1 if loaded or err 
   */
  static UDataMemory *doLoadFromCommonData(UBool isICUData, const char * /*pkgName*/, 
          const char * /*dataPath*/, const char * /*tocEntryPathSuffix*/, const char *tocEntryName,
              /* following arguments are the same as doOpenChoice itself */
              const char *path, const char *type, const char *name,
               UDataMemoryIsAcceptable *isAcceptable, void *context,
               UErrorCode *subErrorCode,
               UErrorCode *pErrorCode)
  {
      UDataMemory        *pEntryData;
      const DataHeader   *pHeader;
      UDataMemory        *pCommonData;
      int32_t            commonDataIndex;
      /* try to get common data.  The loop is for platforms such as the 390 that do
       *  not initially load the full set of ICU data.  If the lookup of an ICU data item
       *  fails, the full (but slower to load) set is loaded, the and the loop repeats,
       *  trying the lookup again.  Once the full set of ICU data is loaded, the loop wont
       *  repeat because the full set will be checked the first time through.
       *
       *  The loop also handles the fallback to a .dat file if the application linked
       *   to the stub data library rather than a real library.
       */
      for (commonDataIndex = isICUData ? 0 : -1;;) {
          pCommonData=openCommonData(path, commonDataIndex, subErrorCode); /** search for pkg **/
  
          if(U_SUCCESS(*subErrorCode) && pCommonData!=NULL) {
              int32_t length;
  
              /* look up the data piece in the common data */
              pHeader=pCommonData->vFuncs->Lookup(pCommonData, tocEntryName, &length, subErrorCode);
  #ifdef UDATA_DEBUG
              fprintf(stderr, "%s: pHeader=%p - %s\n", tocEntryName, pHeader, u_errorName(*subErrorCode));
  #endif
  
              if(pHeader!=NULL) {
                  pEntryData = checkDataItem(pHeader, isAcceptable, context, type, name, subErrorCode, pErrorCode);
  #ifdef UDATA_DEBUG
                  fprintf(stderr, "pEntryData=%p\n", pEntryData);
  #endif
                  if (U_FAILURE(*pErrorCode)) {
                      return NULL;
                  }
                  if (pEntryData != NULL) {
                      pEntryData->length = length;
                      return pEntryData;
                  }
              }
          }
          /* Data wasn't found.  If we were looking for an ICUData item and there is
           * more data available, load it and try again,
           * otherwise break out of this loop. */
          if (!isICUData) {
              return NULL;
          } else if (pCommonData != NULL) {
              ++commonDataIndex;  /* try the next data package */
          } else if (extendICUData(subErrorCode)) {
              /* try this data package slot again: it changed from NULL to non-NULL */
          } else {
              return NULL;
          }
      }
  }
  
  /*
   *  A note on the ownership of Mapped Memory
   *
   *  For common format files, ownership resides with the UDataMemory object
   *    that lives in the cache of opened common data.  These UDataMemorys are private
   *    to the udata implementation, and are never seen directly by users.
   *
   *    The UDataMemory objects returned to users will have the address of some desired
   *    data within the mapped region, but they wont have the mapping info itself, and thus
   *    won't cause anything to be removed from memory when they are closed.
   *
   *  For individual data files, the UDataMemory returned to the user holds the
   *  information necessary to unmap the data on close.  If the user independently
   *  opens the same data file twice, two completely independent mappings will be made.
   *  (There is no cache of opened data items from individual files, only a cache of
   *   opened Common Data files, that is, files containing a collection of data items.)
   *
   *  For common data passed in from the user via udata_setAppData() or
   *  udata_setCommonData(), ownership remains with the user.
   *
   *  UDataMemory objects themselves, as opposed to the memory they describe,
   *  can be anywhere - heap, stack/local or global.
   *  They have a flag to indicate when they're heap allocated and thus
   *  must be deleted when closed.
   */
  
  
  /*----------------------------------------------------------------------------*
   *                                                                            *
   * main data loading functions                                                *
   *                                                                            *
   *----------------------------------------------------------------------------*/
  static UDataMemory *
  doOpenChoice(const char *path, const char *type, const char *name,
               UDataMemoryIsAcceptable *isAcceptable, void *context,
               UErrorCode *pErrorCode)
  {
      UDataMemory         *retVal = NULL;
  
      const char         *dataPath;
  
      int32_t             tocEntrySuffixIndex;
      const char         *tocEntryPathSuffix;
      UErrorCode          subErrorCode=U_ZERO_ERROR;
      const char         *treeChar;
  
      UBool               isICUData = FALSE;
  
  
      /* Is this path ICU data? */
      if(path == NULL ||
         !strcmp(path, U_ICUDATA_ALIAS) ||  /* "ICUDATA" */
         !uprv_strncmp(path, U_ICUDATA_NAME U_TREE_SEPARATOR_STRING, /* "icudt26e-" */
                       uprv_strlen(U_ICUDATA_NAME U_TREE_SEPARATOR_STRING)) ||  
         !uprv_strncmp(path, U_ICUDATA_ALIAS U_TREE_SEPARATOR_STRING, /* "ICUDATA-" */
                       uprv_strlen(U_ICUDATA_ALIAS U_TREE_SEPARATOR_STRING))) {
        isICUData = TRUE;
      }
  
  #if (U_FILE_SEP_CHAR != U_FILE_ALT_SEP_CHAR)  /* Windows:  try "foo\bar" and "foo/bar" */
      /* remap from alternate path char to the main one */
      CharString altSepPath;
      if(path) {
          if(uprv_strchr(path,U_FILE_ALT_SEP_CHAR) != NULL) {
              altSepPath.append(path, *pErrorCode);
              char *p;
              while((p=uprv_strchr(altSepPath.data(), U_FILE_ALT_SEP_CHAR))) {
                  *p = U_FILE_SEP_CHAR;
              }
  #if defined (UDATA_DEBUG)
              fprintf(stderr, "Changed path from [%s] to [%s]\n", path, altSepPath.s);
  #endif
              path = altSepPath.data();
          }
      }
  #endif
  
      CharString tocEntryName; /* entry name in tree format. ex:  'icudt28b/coll/ar.res' */
      CharString tocEntryPath; /* entry name in path format. ex:  'icudt28b\\coll\\ar.res' */
  
      CharString pkgName;
      CharString treeName;
  
      /* ======= Set up strings */
      if(path==NULL) {
          pkgName.append(U_ICUDATA_NAME, *pErrorCode);
      } else {
          const char *pkg;
          const char *first;
          pkg = uprv_strrchr(path, U_FILE_SEP_CHAR);
          first = uprv_strchr(path, U_FILE_SEP_CHAR);
          if(uprv_pathIsAbsolute(path) || (pkg != first)) { /* more than one slash in the path- not a tree name */
              /* see if this is an /absolute/path/to/package  path */
              if(pkg) {
                  pkgName.append(pkg+1, *pErrorCode);
              } else {
                  pkgName.append(path, *pErrorCode);
              }
          } else {
              treeChar = uprv_strchr(path, U_TREE_SEPARATOR);
              if(treeChar) { 
                  treeName.append(treeChar+1, *pErrorCode); /* following '-' */
                  if(isICUData) {
                      pkgName.append(U_ICUDATA_NAME, *pErrorCode);
                  } else {
                      pkgName.append(path, (int32_t)(treeChar-path), *pErrorCode);
                      if (first == NULL) {
                          /*
                          This user data has no path, but there is a tree name.
                          Look up the correct path from the data cache later.
                          */
                          path = pkgName.data();
                      }
                  }
              } else {
                  if(isICUData) {
                      pkgName.append(U_ICUDATA_NAME, *pErrorCode);
                  } else {
                      pkgName.append(path, *pErrorCode);
                  }
              }
          }
      }
  
  #ifdef UDATA_DEBUG
      fprintf(stderr, " P=%s T=%s\n", pkgName.data(), treeName.data());
  #endif
  
      /* setting up the entry name and file name 
       * Make up a full name by appending the type to the supplied
       *  name, assuming that a type was supplied.
       */
  
      /* prepend the package */
      tocEntryName.append(pkgName, *pErrorCode);
      tocEntryPath.append(pkgName, *pErrorCode);
      tocEntrySuffixIndex = tocEntryName.length();
  
      if(!treeName.isEmpty()) {
          tocEntryName.append(U_TREE_ENTRY_SEP_CHAR, *pErrorCode).append(treeName, *pErrorCode);
          tocEntryPath.append(U_FILE_SEP_CHAR, *pErrorCode).append(treeName, *pErrorCode);
      }
  
      tocEntryName.append(U_TREE_ENTRY_SEP_CHAR, *pErrorCode).append(name, *pErrorCode);
      tocEntryPath.append(U_FILE_SEP_CHAR, *pErrorCode).append(name, *pErrorCode);
      if(type!=NULL && *type!=0) {
          tocEntryName.append(".", *pErrorCode).append(type, *pErrorCode);
          tocEntryPath.append(".", *pErrorCode).append(type, *pErrorCode);
      }
      tocEntryPathSuffix = tocEntryPath.data()+tocEntrySuffixIndex; /* suffix starts here */
  
  #ifdef UDATA_DEBUG
      fprintf(stderr, " tocEntryName = %s\n", tocEntryName.data());
      fprintf(stderr, " tocEntryPath = %s\n", tocEntryName.data());
  #endif
  
      if(path == NULL) {
          path = COMMON_DATA_NAME; /* "icudt26e" */
      }
  
      /************************ Begin loop looking for ind. files ***************/
  #ifdef UDATA_DEBUG
      fprintf(stderr, "IND: inBasename = %s, pkg=%s\n", "(n/a)", packageNameFromPath(path));
  #endif
  
      /* End of dealing with a null basename */
      dataPath = u_getDataDirectory();
  
      /****    COMMON PACKAGE  - only if packages are first. */
      if(gDataFileAccess == UDATA_PACKAGES_FIRST) {
  #ifdef UDATA_DEBUG
          fprintf(stderr, "Trying packages (UDATA_PACKAGES_FIRST)\n");
  #endif
          /* #2 */
          retVal = doLoadFromCommonData(isICUData, 
                              pkgName.data(), dataPath, tocEntryPathSuffix, tocEntryName.data(),
                              path, type, name, isAcceptable, context, &subErrorCode, pErrorCode);
          if((retVal != NULL) || U_FAILURE(*pErrorCode)) {
              return retVal;
          }
      }
  
      /****    INDIVIDUAL FILES  */
      if((gDataFileAccess==UDATA_PACKAGES_FIRST) ||
         (gDataFileAccess==UDATA_FILES_FIRST)) {
  #ifdef UDATA_DEBUG
          fprintf(stderr, "Trying individual files\n");
  #endif
          /* Check to make sure that there is a dataPath to iterate over */
          if ((dataPath && *dataPath) || !isICUData) {
              retVal = doLoadFromIndividualFiles(pkgName.data(), dataPath, tocEntryPathSuffix,
                              path, type, name, isAcceptable, context, &subErrorCode, pErrorCode);
              if((retVal != NULL) || U_FAILURE(*pErrorCode)) {
                  return retVal;
              }
          }
      }
  
      /****    COMMON PACKAGE  */
      if((gDataFileAccess==UDATA_ONLY_PACKAGES) || 
         (gDataFileAccess==UDATA_FILES_FIRST)) {
  #ifdef UDATA_DEBUG
          fprintf(stderr, "Trying packages (UDATA_ONLY_PACKAGES || UDATA_FILES_FIRST)\n");
  #endif
          retVal = doLoadFromCommonData(isICUData,
                              pkgName.data(), dataPath, tocEntryPathSuffix, tocEntryName.data(),
                              path, type, name, isAcceptable, context, &subErrorCode, pErrorCode);
          if((retVal != NULL) || U_FAILURE(*pErrorCode)) {
              return retVal;
          }
      }
      
      /* Load from DLL.  If we haven't attempted package load, we also haven't had any chance to
          try a DLL (static or setCommonData/etc)  load.
           If we ever have a "UDATA_ONLY_FILES", add it to the or list here.  */  
      if(gDataFileAccess==UDATA_NO_FILES) {
  #ifdef UDATA_DEBUG
          fprintf(stderr, "Trying common data (UDATA_NO_FILES)\n");
  #endif
          retVal = doLoadFromCommonData(isICUData,
                              pkgName.data(), "", tocEntryPathSuffix, tocEntryName.data(),
                              path, type, name, isAcceptable, context, &subErrorCode, pErrorCode);
          if((retVal != NULL) || U_FAILURE(*pErrorCode)) {
              return retVal;
          }
      }
  
      /* data not found */
      if(U_SUCCESS(*pErrorCode)) {
          if(U_SUCCESS(subErrorCode)) {
              /* file not found */
              *pErrorCode=U_FILE_ACCESS_ERROR;
          } else {
              /* entry point not found or rejected */
              *pErrorCode=subErrorCode;
          }
      }
      return retVal;
  }
  
  
  
  /* API ---------------------------------------------------------------------- */
  
  U_CAPI UDataMemory * U_EXPORT2
  udata_open(const char *path, const char *type, const char *name,
             UErrorCode *pErrorCode) {
  #ifdef UDATA_DEBUG
    fprintf(stderr, "udata_open(): Opening: %s : %s . %s\n", (path?path:"NULL"), name, type);
      fflush(stderr);
  #endif
  
      if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
          return NULL;
      } else if(name==NULL || *name==0) {
          *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
          return NULL;
      } else {
          return doOpenChoice(path, type, name, NULL, NULL, pErrorCode);
      }
  }
  
  
  
  U_CAPI UDataMemory * U_EXPORT2
  udata_openChoice(const char *path, const char *type, const char *name,
                   UDataMemoryIsAcceptable *isAcceptable, void *context,
                   UErrorCode *pErrorCode) {
  #ifdef UDATA_DEBUG
    fprintf(stderr, "udata_openChoice(): Opening: %s : %s . %s\n", (path?path:"NULL"), name, type);
  #endif
  
      if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
          return NULL;
      } else if(name==NULL || *name==0 || isAcceptable==NULL) {
          *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
          return NULL;
      } else {
          return doOpenChoice(path, type, name, isAcceptable, context, pErrorCode);
      }
  }
  
  
  
  U_CAPI void U_EXPORT2
  udata_getInfo(UDataMemory *pData, UDataInfo *pInfo) {
      if(pInfo!=NULL) {
          if(pData!=NULL && pData->pHeader!=NULL) {
              const UDataInfo *info=&pData->pHeader->info;
              uint16_t dataInfoSize=udata_getInfoSize(info);
              if(pInfo->size>dataInfoSize) {
                  pInfo->size=dataInfoSize;
              }
              uprv_memcpy((uint16_t *)pInfo+1, (const uint16_t *)info+1, pInfo->size-2);
              if(info->isBigEndian!=U_IS_BIG_ENDIAN) {
                  /* opposite endianness */
                  uint16_t x=info->reservedWord;
                  pInfo->reservedWord=(uint16_t)((x<<8)|(x>>8));
              }
          } else {
              pInfo->size=0;
          }
      }
  }
  
  
  U_CAPI void U_EXPORT2 udata_setFileAccess(UDataFileAccess access, UErrorCode * /*status*/)
  {
      gDataFileAccess = access;
  }
  