Check in the pristine copy of ICU 4.6...

icu46/source/common/unicode/udata.h

+/*
+******************************************************************************
+*
+*   Copyright (C) 1999-2010, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+*
+******************************************************************************
+*   file name:  udata.h
+*   encoding:   US-ASCII
+*   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"
+#include "unicode/localpointer.h"
+
+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>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.
+ * I 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_STABLE 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. (http://icu-project.org/userguide/icudata.html)</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_STABLE 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_STABLE void U_EXPORT2
+udata_close(UDataMemory *pData);
+
+#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
+
+/**
+ * Get the pointer to the actual data inside the data memory.
+ * The data is read-only.
+ * @param pData The pointer to data memory object
+ * @stable ICU 2.0
+ */
+U_STABLE 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_STABLE 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.
+ *
+ * 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_STABLE 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.
+ *
+ * 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 specifed 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_STABLE 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) */
+    UDATA_FILES_FIRST,
+    /** ICU only loads data from packages, not from single files. */
+    UDATA_ONLY_PACKAGES,
+    /** ICU loads data from packages first, and only from single files
+        if the data cannot be found in a package. */
+    UDATA_PACKAGES_FIRST,
+    /** ICU does not access the file system for data loading. */
+    UDATA_NO_FILES,
+    /** An alias for the default access mode. */
+    UDATA_DEFAULT_ACCESS = UDATA_FILES_FIRST,
+    UDATA_FILE_ACCESS_COUNT
+} 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_STABLE void U_EXPORT2
+udata_setFileAccess(UDataFileAccess access, UErrorCode *status);
+
+U_CDECL_END
+
+#endif