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  *                 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     /**
56      * Variable-length array declared with length 1 to disable bounds checkers.
57      * The actual array length is in the count field.
58      */
59     UDataOffsetTOCEntry entry[1];
60 } UDataOffsetTOC;
61 
62 /**
63  * Get the header size from a const DataHeader *udh.
64  * Handles opposite-endian data.
65  *
66  * @internal
67  */
68 U_CFUNC uint16_t
69 udata_getHeaderSize(const DataHeader *udh);
70 
71 /**
72  * Get the UDataInfo.size from a const UDataInfo *info.
73  * Handles opposite-endian data.
74  *
75  * @internal
76  */
77 U_CFUNC uint16_t
78 udata_getInfoSize(const UDataInfo *info);
79 
80 U_CDECL_BEGIN
81 /*
82  *  "Virtual" functions for data lookup.
83  *  To call one, given a UDataMemory *p, the code looks like this:
84  *     p->vFuncs.Lookup(p, tocEntryName, pErrorCode);
85  *          (I sure do wish this was written in C++, not C)
86  */
87 
88 typedef const DataHeader *
89 (U_CALLCONV * LookupFn)(const UDataMemory *pData,
90                         const char *tocEntryName,
91                         int32_t *pLength,
92                         UErrorCode *pErrorCode);
93 
94 typedef uint32_t
95 (U_CALLCONV * NumEntriesFn)(const UDataMemory *pData);
96 
97 U_CDECL_END
98 
99 typedef struct {
100     LookupFn      Lookup;
101     NumEntriesFn  NumEntries;
102 } commonDataFuncs;
103 
104 
105 /*
106  *  Functions to check whether a UDataMemory refers to memory containing
107  *     a recognizable header and table of contents a Common Data Format
108  *
109  *     If a valid header and TOC are found,
110  *         set the CommonDataFuncs function dispatch vector in the UDataMemory
111  *             to point to the right functions for the TOC type.
112  *     otherwise
113  *         set an errorcode.
114  */
115 U_CFUNC void udata_checkCommonData(UDataMemory *pData, UErrorCode *pErrorCode);
116 
117 #endif
118