/*

******************************************************************************

*

*   Copyright (C) 1999-2003, International Business Machines

*   Corporation and others.  All Rights Reserved.

*

******************************************************************************/

/*----------------------------------------------------------------------------------

 *

 *   UCommonData   An abstract interface for dealing with ICU Common Data Files.

 *                 ICU Common Data Files are a grouping of a number of individual

 *                 data items (resources, converters, tables, anything) into a

 *                 single file or dll.  The combined format includes a table of

 *                 contents for locating the individual items by name.

 *

 *                 Two formats for the table of contents are supported, which is

 *                 why there is an abstract inteface involved.

 *

 *                 These functions are part of the ICU internal implementation, and

 *                 are not inteded to be used directly by applications.

 */

#ifndef __UCMNDATA_H__

#define __UCMNDATA_H__

#include "unicode/udata.h"

#include "umapfile.h"

#define COMMON_DATA_NAME U_ICUDATA_NAME

typedef struct  {

    uint16_t    headerSize;

    uint8_t     magic1;

    uint8_t     magic2;

} MappedData;

typedef struct  {

    MappedData  dataHeader;

    UDataInfo   info;

} DataHeader;

typedef struct {

    uint32_t nameOffset;

    uint32_t dataOffset;

} UDataOffsetTOCEntry;

typedef struct {

    uint32_t count;

    UDataOffsetTOCEntry entry[2];    /* Actual size of array is from count. */

} UDataOffsetTOC;

/**

 * Get the header size from a const DataHeader *udh.

 * Handles opposite-endian data.

 *

 * @internal

 */

U_CFUNC uint16_t

udata_getHeaderSize(const DataHeader *udh);

/**

 * Get the UDataInfo.size from a const UDataInfo *info.

 * Handles opposite-endian data.

 *

 * @internal

 */

U_CFUNC uint16_t

udata_getInfoSize(const UDataInfo *info);

/*

 *  "Virtual" functions for data lookup.

 *  To call one, given a UDataMemory *p, the code looks like this:

 *     p->vFuncs.Lookup(p, tocEntryName, pErrorCode);

 *          (I sure do wish this was written in C++, not C)

 */

typedef const DataHeader *

(* LookupFn)(const UDataMemory *pData,

             const char *tocEntryName,

             int32_t *pLength,

             UErrorCode *pErrorCode);

typedef uint32_t

(* NumEntriesFn)(const UDataMemory *pData);

typedef struct {

    LookupFn      Lookup;

    NumEntriesFn  NumEntries; 

} commonDataFuncs;

/*

 *  Functions to check whether a UDataMemory refers to memory containing 

 *     a recognizable header and table of contents a Common Data Format

 *

 *     If a valid header and TOC are found,

 *         set the CommonDataFuncs function dispatch vector in the UDataMemory

 *             to point to the right functions for the TOC type.

 *     otherwise

 *         set an errorcode.

 */

void   udata_checkCommonData(UDataMemory *pData, UErrorCode *pErrorCode);

#endif