icuSources/common/ucmndata.h

   1 /*
   2 ******************************************************************************
   3 *
   4 *   Copyright (C) 1999-2010, 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 /*
  75  *  "Virtual" functions for data lookup.
  76  *  To call one, given a UDataMemory *p, the code looks like this:
  77  *     p->vFuncs.Lookup(p, tocEntryName, pErrorCode);
  78  *          (I sure do wish this was written in C++, not C)
  79  */
  80
  81 typedef const DataHeader *
  82 (* LookupFn)(const UDataMemory *pData,
  83              const char *tocEntryName,
  84              int32_t *pLength,
  85              UErrorCode *pErrorCode);
  86
  87 typedef uint32_t
  88 (* NumEntriesFn)(const UDataMemory *pData);
  89
  90 typedef struct {
  91     LookupFn      Lookup;
  92     NumEntriesFn  NumEntries;
  93 } commonDataFuncs;
  94
  95
  96 /*
  97  *  Functions to check whether a UDataMemory refers to memory containing
  98  *     a recognizable header and table of contents a Common Data Format
  99  *
 100  *     If a valid header and TOC are found,
 101  *         set the CommonDataFuncs function dispatch vector in the UDataMemory
 102  *             to point to the right functions for the TOC type.
 103  *     otherwise
 104  *         set an errorcode.
 105  */
 106 U_CFUNC void udata_checkCommonData(UDataMemory *pData, UErrorCode *pErrorCode);
 107
 108 #endif