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 // © 2016 and later: Unicode, Inc. and others.
 // License & terms of use: http://www.unicode.org/copyright.html
 /*
 ******************************************************************************
 *
 *   Copyright (C) 1999-2014, International Business Machines
 *   Corporation and others.  All Rights Reserved.
 *
 ******************************************************************************
 *   file name:  udata.h
 *   encoding:   UTF-8
 *   tab size:   8 (not used)
 *   indentation:4
 *
 *   created on: 1999oct25
 *   created by: Markus W. Scherer
 */
 
 #ifndef __UDATA_H__
 #define __UDATA_H__
 
 #include "unicode/utypes.h"
 
 #if U_SHOW_CPLUSPLUS_API
 #include "unicode/localpointer.h"
 #endif   // U_SHOW_CPLUSPLUS_API
 
 U_CDECL_BEGIN
 
 /**
  * \file
  * \brief C API: Data loading interface
  *
  * <h2>Information about data loading interface</h2>
  *
  * This API is used to find and efficiently load data for ICU and applications
  * using ICU. It provides an abstract interface that specifies a data type and
  * name to find and load the data. Normally this API is used by other ICU APIs
  * to load required data out of the ICU data library, but it can be used to
  * load data out of other places.
  *
  * See the User Guide Data Management chapter.
  */
  
 #ifndef U_HIDE_INTERNAL_API
 /**
  * Character used to separate package names from tree names 
  * @internal ICU 3.0
  */
 #define U_TREE_SEPARATOR '-'
 
 /**
  * String used to separate package names from tree names 
  * @internal ICU 3.0
  */
 #define U_TREE_SEPARATOR_STRING "-"
 
 /**
  * Character used to separate parts of entry names
  * @internal ICU 3.0
  */
 #define U_TREE_ENTRY_SEP_CHAR '/'
 
 /**
  * String used to separate parts of entry names
  * @internal ICU 3.0
  */
 #define U_TREE_ENTRY_SEP_STRING "/"
 
 /**
  * Alias for standard ICU data 
  * @internal ICU 3.0
  */
 #define U_ICUDATA_ALIAS "ICUDATA"
 
 #endif /* U_HIDE_INTERNAL_API */
 
 /**
  * UDataInfo contains the properties about the requested data.
  * This is meta data.
  *
  * <p>This structure may grow in the future, indicated by the
  * <code>size</code> field.</p>
  *
  * <p>ICU data must be at least 8-aligned, and should be 16-aligned.
  * The UDataInfo struct begins 4 bytes after the start of the data item,
  * so it is 4-aligned.
  *
  * <p>The platform data property fields help determine if a data
  * file can be efficiently used on a given machine.
  * The particular fields are of importance only if the data
  * is affected by the properties - if there is integer data
  * with word sizes > 1 byte, char* text, or UChar* text.</p>
  *
  * <p>The implementation for the <code>udata_open[Choice]()</code>
  * functions may reject data based on the value in <code>isBigEndian</code>.
  * No other field is used by the <code>udata</code> API implementation.</p>
  *
  * <p>The <code>dataFormat</code> may be used to identify
  * the kind of data, e.g. a converter table.</p>
  *
  * <p>The <code>formatVersion</code> field should be used to
  * make sure that the format can be interpreted.
  * It may be a good idea to check only for the one or two highest
  * of the version elements to allow the data memory to
  * get more or somewhat rearranged contents, for as long
  * as the using code can still interpret the older contents.</p>
  *
  * <p>The <code>dataVersion</code> field is intended to be a
  * common place to store the source version of the data;
  * for data from the Unicode character database, this could
  * reflect the Unicode version.</p>
  *
  * @stable ICU 2.0
  */
 typedef struct {
     /** sizeof(UDataInfo)
      *  @stable ICU 2.0 */
     uint16_t size;
 
     /** unused, set to 0 
      *  @stable ICU 2.0*/
     uint16_t reservedWord;
 
     /* platform data properties */
     /** 0 for little-endian machine, 1 for big-endian
      *  @stable ICU 2.0 */
     uint8_t isBigEndian;
 
     /** see U_CHARSET_FAMILY values in utypes.h 
      *  @stable ICU 2.0*/
     uint8_t charsetFamily;
 
     /** sizeof(UChar), one of { 1, 2, 4 } 
      *  @stable ICU 2.0*/
     uint8_t sizeofUChar;
 
     /** unused, set to 0 
      *  @stable ICU 2.0*/
     uint8_t reservedByte;
 
     /** data format identifier 
      *  @stable ICU 2.0*/
     uint8_t dataFormat[4];
 
     /** versions: [0] major [1] minor [2] milli [3] micro 
      *  @stable ICU 2.0*/
     uint8_t formatVersion[4];
 
     /** versions: [0] major [1] minor [2] milli [3] micro 
      *  @stable ICU 2.0*/
     uint8_t dataVersion[4];
 } UDataInfo;
 
 /* API for reading data -----------------------------------------------------*/
 
 /**
  * Forward declaration of the data memory type.
  * @stable ICU 2.0
  */
 typedef struct UDataMemory UDataMemory;
 
 /**
  * Callback function for udata_openChoice().
  * @param context parameter passed into <code>udata_openChoice()</code>.
  * @param type The type of the data as passed into <code>udata_openChoice()</code>.
  *             It may be <code>NULL</code>.
  * @param name The name of the data as passed into <code>udata_openChoice()</code>.
  * @param pInfo A pointer to the <code>UDataInfo</code> structure
  *              of data that has been loaded and will be returned
  *              by <code>udata_openChoice()</code> if this function
  *              returns <code>true</code>.
  * @return true if the current data memory is acceptable
  * @stable ICU 2.0
  */
 typedef UBool U_CALLCONV
 UDataMemoryIsAcceptable(void *context,
                         const char *type, const char *name,
                         const UDataInfo *pInfo);
 
 
 /**
  * Convenience function.
  * This function works the same as <code>udata_openChoice</code>
  * except that any data that matches the type and name
  * is assumed to be acceptable.
  * @param path Specifies an absolute path and/or a basename for the
  *             finding of the data in the file system.
  *             <code>NULL</code> for ICU data.
  * @param type A string that specifies the type of data to be loaded.
  *             For example, resource bundles are loaded with type "res",
  *             conversion tables with type "cnv".
  *             This may be <code>NULL</code> or empty.
  * @param name A string that specifies the name of the data.
  * @param pErrorCode An ICU UErrorCode parameter. It must not be <code>NULL</code>.
  * @return A pointer (handle) to a data memory object, or <code>NULL</code>
  *         if an error occurs. Call <code>udata_getMemory()</code>
  *         to get a pointer to the actual data.
  *
  * @see udata_openChoice
  * @stable ICU 2.0
  */
 U_CAPI UDataMemory * U_EXPORT2
 udata_open(const char *path, const char *type, const char *name,
            UErrorCode *pErrorCode);
 
 /**
  * Data loading function.
  * This function is used to find and load efficiently data for
  * ICU and applications using ICU.
  * It provides an abstract interface that allows to specify a data
  * type and name to find and load the data.
  *
  * <p>The implementation depends on platform properties and user preferences
  * and may involve loading shared libraries (DLLs), mapping
  * files into memory, or fopen()/fread() files.
  * It may also involve using static memory or database queries etc.
  * Several or all data items may be combined into one entity
  * (DLL, memory-mappable file).</p>
  *
  * <p>The data is always preceded by a header that includes
  * a <code>UDataInfo</code> structure.
  * The caller's <code>isAcceptable()</code> function is called to make
  * sure that the data is useful. It may be called several times if it
  * rejects the data and there is more than one location with data
  * matching the type and name.</p>
  *
  * <p>If <code>path==NULL</code>, then ICU data is loaded.
  * Otherwise, it is separated into a basename and a basename-less directory string.
  * The basename is used as the data package name, and the directory is
  * logically prepended to the ICU data directory string.</p>
  *
  * <p>For details about ICU data loading see the User Guide
  * Data Management chapter. (https://unicode-org.github.io/icu/userguide/icu_data/)</p>
  *
  * @param path Specifies an absolute path and/or a basename for the
  *             finding of the data in the file system.
  *             <code>NULL</code> for ICU data.
  * @param type A string that specifies the type of data to be loaded.
  *             For example, resource bundles are loaded with type "res",
  *             conversion tables with type "cnv".
  *             This may be <code>NULL</code> or empty.
  * @param name A string that specifies the name of the data.
  * @param isAcceptable This function is called to verify that loaded data
  *                     is useful for the client code. If it returns false
  *                     for all data items, then <code>udata_openChoice()</code>
  *                     will return with an error.
  * @param context Arbitrary parameter to be passed into isAcceptable.
  * @param pErrorCode An ICU UErrorCode parameter. It must not be <code>NULL</code>.
  * @return A pointer (handle) to a data memory object, or <code>NULL</code>
  *         if an error occurs. Call <code>udata_getMemory()</code>
  *         to get a pointer to the actual data.
  * @stable ICU 2.0
  */
 U_CAPI UDataMemory * U_EXPORT2
 udata_openChoice(const char *path, const char *type, const char *name,
                  UDataMemoryIsAcceptable *isAcceptable, void *context,
                  UErrorCode *pErrorCode);
 
 /**
  * Close the data memory.
  * This function must be called to allow the system to
  * release resources associated with this data memory.
  * @param pData The pointer to data memory object
  * @stable ICU 2.0
  */
 U_CAPI void U_EXPORT2
 udata_close(UDataMemory *pData);
 
 /**
  * Get the pointer to the actual data inside the data memory.
  * The data is read-only.
  *
  * ICU data must be at least 8-aligned, and should be 16-aligned.
  *
  * @param pData The pointer to data memory object
  * @stable ICU 2.0
  */
 U_CAPI const void * U_EXPORT2
 udata_getMemory(UDataMemory *pData);
 
 /**
  * Get the information from the data memory header.
  * This allows to get access to the header containing
  * platform data properties etc. which is not part of
  * the data itself and can therefore not be accessed
  * via the pointer that <code>udata_getMemory()</code> returns.
  *
  * @param pData pointer to the data memory object
  * @param pInfo pointer to a UDataInfo object;
  *              its <code>size</code> field must be set correctly,
  *              typically to <code>sizeof(UDataInfo)</code>.
  *
  * <code>*pInfo</code> will be filled with the UDataInfo structure
  * in the data memory object. If this structure is smaller than
  * <code>pInfo->size</code>, then the <code>size</code> will be
  * adjusted and only part of the structure will be filled.
  * @stable ICU 2.0
  */
 U_CAPI void U_EXPORT2
 udata_getInfo(UDataMemory *pData, UDataInfo *pInfo);
 
 /**
  * This function bypasses the normal ICU data loading process and
  * allows you to force ICU's system data to come out of a user-specified
  * area in memory.
  *
  * ICU data must be at least 8-aligned, and should be 16-aligned.
  * See https://unicode-org.github.io/icu/userguide/icu_data
  *
  * The format of this data is that of the icu common data file, as is
  * generated by the pkgdata tool with mode=common or mode=dll.
  * You can read in a whole common mode file and pass the address to the start of the
  * data, or (with the appropriate link options) pass in the pointer to
  * the data that has been loaded from a dll by the operating system,
  * as shown in this code:
  *
  *       extern const char U_IMPORT U_ICUDATA_ENTRY_POINT [];
  *        // U_ICUDATA_ENTRY_POINT is same as entry point specified to pkgdata tool
  *       UErrorCode  status = U_ZERO_ERROR;
  *
  *       udata_setCommonData(&U_ICUDATA_ENTRY_POINT, &status);
  *
  * It is important that the declaration be as above. The entry point
  * must not be declared as an extern void*.
  *
  * Starting with ICU 4.4, it is possible to set several data packages,
  * one per call to this function.
  * udata_open() will look for data in the multiple data packages in the order
  * in which they were set.
  * The position of the linked-in or default-name ICU .data package in the
  * search list depends on when the first data item is loaded that is not contained
  * in the already explicitly set packages.
  * If data was loaded implicitly before the first call to this function
  * (for example, via opening a converter, constructing a UnicodeString
  * from default-codepage data, using formatting or collation APIs, etc.),
  * then the default data will be first in the list.
  *
  * This function has no effect on application (non ICU) data.  See udata_setAppData()
  * for similar functionality for application data.
  *
  * @param data pointer to ICU common data
  * @param err outgoing error status <code>U_USING_DEFAULT_WARNING, U_UNSUPPORTED_ERROR</code>
  * @stable ICU 2.0
  */
 U_CAPI void U_EXPORT2
 udata_setCommonData(const void *data, UErrorCode *err);
 
 
 /**
  * This function bypasses the normal ICU data loading process for application-specific
  * data and allows you to force the it to come out of a user-specified
  * pointer.
  *
  * ICU data must be at least 8-aligned, and should be 16-aligned.
  * See https://unicode-org.github.io/icu/userguide/icu_data
  *
  * The format of this data is that of the icu common data file, like 'icudt26l.dat'
  * or the corresponding shared library (DLL) file.
  * The application must read in or otherwise construct an image of the data and then
  * pass the address of it to this function.
  *
  *
  * Warning:  setAppData will set a U_USING_DEFAULT_WARNING code if
  *           data with the specified path that has already been opened, or
  *           if setAppData with the same path has already been called.
  *           Any such calls to setAppData will have no effect.
  *
  *
  * @param packageName the package name by which the application will refer
  *             to (open) this data
  * @param data pointer to the data
  * @param err outgoing error status <code>U_USING_DEFAULT_WARNING, U_UNSUPPORTED_ERROR</code>
  * @see udata_setCommonData
  * @stable ICU 2.0
  */
 U_CAPI void U_EXPORT2
 udata_setAppData(const char *packageName, const void *data, UErrorCode *err);
 
 /**
  * Possible settings for udata_setFileAccess()
  * @see udata_setFileAccess
  * @stable ICU 3.4
  */
 typedef enum UDataFileAccess {
     /** ICU looks for data in single files first, then in packages. (default) @stable ICU 3.4 */
     UDATA_FILES_FIRST,
     /** An alias for the default access mode. @stable ICU 3.4 */
     UDATA_DEFAULT_ACCESS = UDATA_FILES_FIRST,
     /** ICU only loads data from packages, not from single files. @stable ICU 3.4 */
     UDATA_ONLY_PACKAGES,
     /** ICU loads data from packages first, and only from single files
         if the data cannot be found in a package. @stable ICU 3.4 */
     UDATA_PACKAGES_FIRST,
     /** ICU does not access the file system for data loading. @stable ICU 3.4 */
     UDATA_NO_FILES,
 #ifndef U_HIDE_DEPRECATED_API
     /**
      * Number of real UDataFileAccess values.
      * @deprecated ICU 58 The numeric value may change over time, see ICU ticket #12420.
      */
     UDATA_FILE_ACCESS_COUNT
 #endif  // U_HIDE_DEPRECATED_API
 } UDataFileAccess;
 
 /**
  * This function may be called to control how ICU loads data. It must be called
  * before any ICU data is loaded, including application data loaded with 
  * ures/ResourceBundle or udata APIs. This function is not multithread safe.  
  * The results of calling it while other threads are loading data are undefined.
  * @param access The type of file access to be used
  * @param status Error code.
  * @see UDataFileAccess
  * @stable ICU 3.4 
  */
 U_CAPI void U_EXPORT2
 udata_setFileAccess(UDataFileAccess access, UErrorCode *status);
 
 U_CDECL_END
 
 #if U_SHOW_CPLUSPLUS_API
 
 U_NAMESPACE_BEGIN
 
 /**
  * \class LocalUDataMemoryPointer
  * "Smart pointer" class, closes a UDataMemory via udata_close().
  * For most methods see the LocalPointerBase base class.
  *
  * @see LocalPointerBase
  * @see LocalPointer
  * @stable ICU 4.4
  */
 U_DEFINE_LOCAL_OPEN_POINTER(LocalUDataMemoryPointer, UDataMemory, udata_close);
 
 U_NAMESPACE_END
 
 #endif  // U_SHOW_CPLUSPLUS_API
 
 #endif

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