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      1 /*
      2 ******************************************************************************
      3 *
      4 *   Copyright (C) 1999-2011, International Business Machines
      5 *   Corporation and others.  All Rights Reserved.
      6 *
      7 ******************************************************************************/
      8 
      9 
     10 /*----------------------------------------------------------------------------------
     11  *
     12  *   UCommonData   An abstract interface for dealing with ICU Common Data Files.
     13  *                 ICU Common Data Files are a grouping of a number of individual
     14  *                 data items (resources, converters, tables, anything) into a
     15  *                 single file or dll.  The combined format includes a table of
     16  *                 contents for locating the individual items by name.
     17  *
     18  *                 Two formats for the table of contents are supported, which is
     19  *                 why there is an abstract inteface involved.
     20  *
     21  *                 These functions are part of the ICU internal implementation, and
     22  *                 are not inteded to be used directly by applications.
     23  */
     24 
     25 #ifndef __UCMNDATA_H__
     26 #define __UCMNDATA_H__
     27 
     28 #include "unicode/udata.h"
     29 #include "umapfile.h"
     30 
     31 
     32 #define COMMON_DATA_NAME U_ICUDATA_NAME
     33 
     34 typedef struct  {
     35     uint16_t    headerSize;
     36     uint8_t     magic1;
     37     uint8_t     magic2;
     38 } MappedData;
     39 
     40 
     41 typedef struct  {
     42     MappedData  dataHeader;
     43     UDataInfo   info;
     44 } DataHeader;
     45 
     46 typedef struct {
     47     uint32_t nameOffset;
     48     uint32_t dataOffset;
     49 } UDataOffsetTOCEntry;
     50 
     51 typedef struct {
     52     uint32_t count;
     53     UDataOffsetTOCEntry entry[2];    /* Actual size of array is from count. */
     54 } UDataOffsetTOC;
     55 
     56 /**
     57  * Get the header size from a const DataHeader *udh.
     58  * Handles opposite-endian data.
     59  *
     60  * @internal
     61  */
     62 U_CFUNC uint16_t
     63 udata_getHeaderSize(const DataHeader *udh);
     64 
     65 /**
     66  * Get the UDataInfo.size from a const UDataInfo *info.
     67  * Handles opposite-endian data.
     68  *
     69  * @internal
     70  */
     71 U_CFUNC uint16_t
     72 udata_getInfoSize(const UDataInfo *info);
     73 
     74 U_CDECL_BEGIN
     75 /*
     76  *  "Virtual" functions for data lookup.
     77  *  To call one, given a UDataMemory *p, the code looks like this:
     78  *     p->vFuncs.Lookup(p, tocEntryName, pErrorCode);
     79  *          (I sure do wish this was written in C++, not C)
     80  */
     81 
     82 typedef const DataHeader *
     83 (U_CALLCONV * LookupFn)(const UDataMemory *pData,
     84                         const char *tocEntryName,
     85                         int32_t *pLength,
     86                         UErrorCode *pErrorCode);
     87 
     88 typedef uint32_t
     89 (U_CALLCONV * NumEntriesFn)(const UDataMemory *pData);
     90 
     91 U_CDECL_END
     92 
     93 typedef struct {
     94     LookupFn      Lookup;
     95     NumEntriesFn  NumEntries;
     96 } commonDataFuncs;
     97 
     98 
     99 /*
    100  *  Functions to check whether a UDataMemory refers to memory containing
    101  *     a recognizable header and table of contents a Common Data Format
    102  *
    103  *     If a valid header and TOC are found,
    104  *         set the CommonDataFuncs function dispatch vector in the UDataMemory
    105  *             to point to the right functions for the TOC type.
    106  *     otherwise
    107  *         set an errorcode.
    108  */
    109 U_CFUNC void udata_checkCommonData(UDataMemory *pData, UErrorCode *pErrorCode);
    110 
    111 #endif
    112