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      1 // Copyright (C) 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  *                 These functions are part of the ICU internal implementation, and
     24  *                 are not inteded to be used directly by applications.
     25  */
     26 
     27 #ifndef __UCMNDATA_H__
     28 #define __UCMNDATA_H__
     29 
     30 #include "unicode/udata.h"
     31 #include "umapfile.h"
     32 
     33 
     34 #define COMMON_DATA_NAME U_ICUDATA_NAME
     35 
     36 typedef struct  {
     37     uint16_t    headerSize;
     38     uint8_t     magic1;
     39     uint8_t     magic2;
     40 } MappedData;
     41 
     42 
     43 typedef struct  {
     44     MappedData  dataHeader;
     45     UDataInfo   info;
     46 } DataHeader;
     47 
     48 typedef struct {
     49     uint32_t nameOffset;
     50     uint32_t dataOffset;
     51 } UDataOffsetTOCEntry;
     52 
     53 typedef struct {
     54     uint32_t count;
     55     UDataOffsetTOCEntry entry[2];    /* Actual size of array is from count. */
     56 } UDataOffsetTOC;
     57 
     58 /**
     59  * Get the header size from a const DataHeader *udh.
     60  * Handles opposite-endian data.
     61  *
     62  * @internal
     63  */
     64 U_CFUNC uint16_t
     65 udata_getHeaderSize(const DataHeader *udh);
     66 
     67 /**
     68  * Get the UDataInfo.size from a const UDataInfo *info.
     69  * Handles opposite-endian data.
     70  *
     71  * @internal
     72  */
     73 U_CFUNC uint16_t
     74 udata_getInfoSize(const UDataInfo *info);
     75 
     76 U_CDECL_BEGIN
     77 /*
     78  *  "Virtual" functions for data lookup.
     79  *  To call one, given a UDataMemory *p, the code looks like this:
     80  *     p->vFuncs.Lookup(p, tocEntryName, pErrorCode);
     81  *          (I sure do wish this was written in C++, not C)
     82  */
     83 
     84 typedef const DataHeader *
     85 (U_CALLCONV * LookupFn)(const UDataMemory *pData,
     86                         const char *tocEntryName,
     87                         int32_t *pLength,
     88                         UErrorCode *pErrorCode);
     89 
     90 typedef uint32_t
     91 (U_CALLCONV * NumEntriesFn)(const UDataMemory *pData);
     92 
     93 U_CDECL_END
     94 
     95 typedef struct {
     96     LookupFn      Lookup;
     97     NumEntriesFn  NumEntries;
     98 } commonDataFuncs;
     99 
    100 
    101 /*
    102  *  Functions to check whether a UDataMemory refers to memory containing
    103  *     a recognizable header and table of contents a Common Data Format
    104  *
    105  *     If a valid header and TOC are found,
    106  *         set the CommonDataFuncs function dispatch vector in the UDataMemory
    107  *             to point to the right functions for the TOC type.
    108  *     otherwise
    109  *         set an errorcode.
    110  */
    111 U_CFUNC void udata_checkCommonData(UDataMemory *pData, UErrorCode *pErrorCode);
    112 
    113 #endif
    114