297 lines
12 KiB
C
297 lines
12 KiB
C
/*
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* Copyright (C) 2007 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* File Porting Layer.
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*/
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#ifndef __DRM_FILE_H__
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#define __DRM_FILE_H__
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <drm_common_types.h>
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/** Type value of a regular file or file name. */
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#define DRM_FILE_ISREG 1
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/** Type value of a directory or directory name. */
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#define DRM_FILE_ISDIR 2
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/** Type value of a filter name */
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#define DRM_FILE_ISFILTER 3
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/** Return code that indicates successful completion of an operation. */
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#define DRM_FILE_SUCCESS 0
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/** Indicates that an operation failed. */
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#define DRM_FILE_FAILURE -1
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/** Indicates that the a DRM_file_read() call reached the end of the file. */
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#define DRM_FILE_EOF -2
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/** Open for read access. */
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#define DRM_FILE_MODE_READ 1
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/** Open for write access. */
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#define DRM_FILE_MODE_WRITE 2
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#ifndef MAX_FILENAME_LEN
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/** Maximum number of characters that a filename may have. By default assumes
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* that the entry results of DRM_file_listNextEntry() are returned in the async state
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* buffer, after the #DRM_file_result_s, and calculates the maximum name
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* from that.
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*/
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#define MAX_FILENAME_LEN 1024
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#endif
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/**
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* Performs one-time initialization of the File System (FS).
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* This function is called once during the lifetime of an application,
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* and before any call to <code>DRM_file_*</code> functions by this application.
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* When several applications are using the file interface, this function may be called
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* several times, once per application.
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*
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* @return #DRM_FILE_SUCCESS, #DRM_FILE_FAILURE.
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*/
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int32_t DRM_file_startup(void);
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/**
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* Returns the length of a file (by name, opened or unopened).
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*
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* @param name Name of the file, UCS-2 encoded.
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* @param nameChars Number characters encoded in name.
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* asynchronous operation returns #DRM_FILE_WOULDBLOCK.
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* @return #DRM_FILE_WOULDBLOCK, #DRM_FILE_FAILURE or the file length.
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*/
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int32_t DRM_file_getFileLength(const uint16_t* name,
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int32_t nameChars);
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/**
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* Initializes a list iteration session.
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*
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* @param prefix Prefix that must be matched, UCS-2 encoded. *
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* @param prefixChars Number characters encoded in prefix.
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* @param session List session identifier.
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* @param iteration List iteration identifier.
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*
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* @return #DRM_FILE_WOULDBLOCK, #DRM_FILE_SUCCESS, #DRM_FILE_FAILURE.
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*/
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int32_t DRM_file_listOpen(const uint16_t* prefix,
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int32_t prefixChars,
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int32_t* session,
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int32_t* iteration);
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/**
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* Used to fetch a list of file names that match a given name prefix.
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*
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* @param prefix See DRM_file_listOpen(). This does not change during the
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* iteration session.
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* @param prefixChars See DRM_file_listOpen(). This does not change during
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* the iteration session.
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* @param entry Buffer parameter to return the next file name that matches the
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* #prefix parameter, if any, when the function returns a positive number of
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* characters.
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* @param entryBytes Size of entry in bytes.
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* @param session See DRM_file_listOpen().
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* @param iteration See DRM_file_listOpen().
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* @return #DRM_FILE_WOULDBLOCK, #DRM_FILE_FAILURE or the number of
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* characters encoded in entry. Returns 0 when the end of the list is reached.
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*/
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int32_t DRM_file_listNextEntry(const uint16_t* prefix,
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int32_t prefixChars,
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uint16_t* entry,
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int32_t entryBytes,
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int32_t* session,
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int32_t* iteration);
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/**
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* Ends a list iteration session. Notifies the implementation
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* that the list session is over and that any session resources
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* can be released.
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*
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* @param session See DRM_file_listOpen().
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* @param iteration See DRM_file_listOpen().
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* @return #DRM_FILE_WOULDBLOCK, #DRM_FILE_SUCCESS, #DRM_FILE_FAILURE.
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*/
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int32_t DRM_file_listClose(int32_t session, int32_t iteration);
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/**
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* Renames a file, given its old name. The file or directory is renamed
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* immediately on the actual file system upon invocation of this method.
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* Any open handles on the file specified by oldName become invalid after
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* this method has been called.
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*
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* @param oldName Current file name (unopened), UCS-2 encoded.
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* @param oldNameChars Number of characters encoded on oldName.
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* @param newName New name for the file (unopened), UCS-2 encoded.
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* @param newNameChars Number of characters encoded on newName.
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* @return #DRM_FILE_WOULDBLOCK, #DRM_FILE_SUCCESS, #DRM_FILE_FAILURE. In particular,
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* #DRM_FILE_FAILURE if a file or directory already exists with the new name.
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*/
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int32_t DRM_file_rename(const uint16_t* oldName,
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int32_t oldNameChars,
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const uint16_t* newName,
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int32_t newNameChars);
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/**
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* Tests if a file exists given its name.
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*
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* @param name Name of the file, UCS-2 encoded.
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* @param nameChars Number of characters encoded in name.
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* @return #DRM_FILE_WOULDBLOCK, #DRM_FILE_ISREG, #DRM_FILE_ISDIR, #DRM_FILE_FAILURE. If name
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* exists, returns #DRM_FILE_ISREG if it is a regular file and #DRM_FILE_ISDIR if it is a directory.
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* Returns #DRM_FILE_FAILURE in all other cases, including those where name exists but is neither
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* a regular file nor a directory. Platforms that do not support directories MUST NOT return
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* #DRM_FILE_ISDIR.
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*/
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int32_t DRM_file_exists(const uint16_t* name,
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int32_t nameChars);
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/**
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* Opens a file with the given name and returns its file handle.
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*
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* @param name Name of the file, UCS-2 encoded.
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* @param nameChars Number of characters encoded in name.
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* @param mode Any combination of the #DRM_FILE_MODE_READ and
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* #DRM_FILE_MODE_WRITE flags. If the file does not exist and mode contains the
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* #DRM_FILE_MODE_WRITE flag, then the file is automatically created. If the
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* file exists and the mode contains the #DRM_FILE_MODE_WRITE flag, the file is
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* opened so it can be modified, but the data is not modified by the open call.
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* In all cases the current position is set to the start of the file.
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* The following table shows how to map the mode semantics above to UNIX
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* fopen-style modes. For brevity in the table, R=#DRM_FILE_MODE_READ,
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* W=#DRM_FILE_MODE_WRITE, E=File exists:
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* <table>
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* <tr><td>RW</td><td>E</td><td>Maps-to</td></tr>
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* <tr><td>00</td><td>0</td><td>Return #DRM_FILE_FAILURE</td></tr>
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* <tr><td>00</td><td>1</td><td>Return #DRM_FILE_FAILURE</td></tr>
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* <tr><td>01</td><td>0</td><td>Use fopen mode "w"</td></tr>
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* <tr><td>01</td><td>1</td><td>Use fopen mode "a" and fseek to the start</td></tr>
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* <tr><td>10</td><td>0</td><td>Return #DRM_FILE_FAILURE</td></tr>
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* <tr><td>10</td><td>1</td><td>Use fopen mode "r"</td></tr>
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* <tr><td>11</td><td>0</td><td>Use fopen mode "w+"</td></tr>
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* <tr><td>11</td><td>1</td><td>Use fopen mode "r+"</td></tr>
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* </table>
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* @param handle Pointer where the result handle value is placed when the function
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* is called synchronously.
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* @return #DRM_FILE_WOULDBLOCK, #DRM_FILE_SUCCESS, #DRM_FILE_FAILURE.
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*/
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int32_t DRM_file_open(const uint16_t* name,
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int32_t nameChars,
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int32_t mode,
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int32_t* handle);
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/**
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* Deletes a file given its name, UCS-2 encoded. The file or directory is
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* deleted immediately on the actual file system upon invocation of this
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* method. Any open handles on the file specified by name become invalid
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* after this method has been called.
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*
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* If the port needs to ensure that a specific application does not exceed a given storage
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* space quota, then the bytes freed by the deletion must be added to the available space for
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* that application.
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*
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* @param name Name of the file, UCS-2 encoded.
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* @param nameChars Number of characters encoded in name.
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* @return #DRM_FILE_WOULDBLOCK, #DRM_FILE_SUCCESS, #DRM_FILE_FAILURE.
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*/
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int32_t DRM_file_delete(const uint16_t* name,
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int32_t nameChars);
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/**
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* Read bytes from a file at the current position to a buffer. Afterwards the
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* new file position is the byte after the last byte read.
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* DRM_FILE_FAILURE is returned if the handle is invalid (e.g., as a
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* consquence of DRM_file_delete, DRM_file_rename, or DRM_file_close).
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*
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* @param handle File handle as returned by DRM_file_open().
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* @param dst Buffer where the data is to be copied.
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* @param length Number of bytes to be copied.
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* @return #DRM_FILE_WOULDBLOCK, #DRM_FILE_SUCCESS, #DRM_FILE_FAILURE, #DRM_FILE_EOF
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* or the number of bytes that were read, i.e. in the range 0..length.
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*/
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int32_t DRM_file_read(int32_t handle,
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uint8_t* dst,
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int32_t length);
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/**
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* Write bytes from a buffer to the file at the current position. If the
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* current position + number of bytes written > current size of the file,
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* then the file is grown. Afterwards the new file position is the byte
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* after the last byte written.
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* DRM_FILE_FAILURE is returned if the handle is invalid (e.g., as a
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* consquence of DRM_file_delete, DRM_file_rename, or DRM_file_close).
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*
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* @param handle File handle as returned by DRM_file_open().
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* @param src Buffer that contains the bytes to be written.
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* @param length Number of bytes to be written.
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* If the port needs to ensure that a specific application does not exceed a given storage
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* space quota, the implementation must make sure the call does not violate that invariant.
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* @return #DRM_FILE_WOULDBLOCK, #DRM_FILE_FAILURE or the number of bytes
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* that were written. This number must be in the range 0..length.
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* Returns #DRM_FILE_FAILURE when storage is full or exceeds quota.
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*/
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int32_t DRM_file_write(int32_t handle,
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const uint8_t* src,
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int32_t length);
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/**
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* Closes a file.
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* DRM_FILE_SUCCESS is returned if the handle is invalid (e.g., as a
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* consquence of DRM_file_delete or DRM_file_rename).
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*
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* @param handle File handle as returned by DRM_file_open().
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* @return #DRM_FILE_WOULDBLOCK, #DRM_FILE_SUCCESS, #DRM_FILE_FAILURE.
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*/
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int32_t DRM_file_close(int32_t handle);
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/**
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* Sets the current position in an opened file.
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* DRM_FILE_FAILURE is returned if the handle is invalid (e.g., as a
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* consquence of DRM_file_delete, DRM_file_rename, or DRM_file_close).
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*
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* @param handle File handle as returned by DRM_file_open().
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* @param value The new current position of the file. If value is greater
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* than the length of the file then the file should be extended. The contents
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* of the newly extended portion of the file is undefined.
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* If the port needs to ensure that a specific application does not exceed a given storage
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* space quota, the implementation must make sure the call does not violate that invariant.
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* @return #DRM_FILE_WOULDBLOCK, #DRM_FILE_SUCCESS, #DRM_FILE_FAILURE.
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* Returns #DRM_FILE_FAILURE when storage is full or exceeds quota.
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*/
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int32_t DRM_file_setPosition(int32_t handle, int32_t value);
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/**
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* Creates a directory with the assigned name and full file permissions on
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* the file system. The full path to the new directory must already exist.
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* The directory is created immediately on the actual file system upon
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* invocation of this method.
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*
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* @param name Name of the directory, UCS-2 encoded.
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* @param nameChars Number of characters encoded in name.
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* @return #DRM_FILE_WOULDBLOCK, #DRM_FILE_SUCCESS, #DRM_FILE_FAILURE.
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*/
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int32_t DRM_file_mkdir(const uint16_t* name,
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int32_t nameChars);
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#ifdef __cplusplus
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}
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#endif
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#endif /* __DRM_FILE_H__ */
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