428 lines
13 KiB
Plaintext
428 lines
13 KiB
Plaintext
/*
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* Copyright 2009-2014 Haiku, Inc. All rights reserved.
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* Distributed under the terms of the MIT License.
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*
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* Authors:
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* Tyler Dauwalder
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* John Scipione, jscipione@gmail.com
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* Ingo Weinhold, bonefish@users.sf.net
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*
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* Corresponds to:
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* headers/os/storage/File.h hrev47402
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* src/kits/storage/File.cpp hrev47402
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*/
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/*!
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\file File.h
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\ingroup storage
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\ingroup libbe
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\brief Provides the BFile class.
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*/
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/*!
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\class BFile
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\ingroup storage
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\ingroup libbe
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\brief Provides the ability to read and write the data of a file.
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The file is automatically opened when you initialize a BFile and is
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automatically closed when you re-initialize or destroy the object.
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Symbolic links are automatically transversed by opening a BFile.
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The node that the BFile ends up opening will be the file or directory
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that the link points to, not the symbolic link file itself.
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\since BeOS R3
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*/
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/*!
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\fn BFile::BFile()
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\brief Creates an uninitialized BFile object.
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Should be followed by a call to one of the SetTo() methods, or an
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assignment:
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- SetTo(const entry_ref* ref, uint32 openMode)
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- SetTo(const BEntry* entry, uint32 openMode)
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- SetTo(const char* path, uint32 openMode)
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- SetTo(const BDirectory* dir, const char* path, uint32 openMode)
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- operator=(const BFile &file)
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\since BeOS R3
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*/
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/*!
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\fn BFile::BFile(const BFile& file)
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\brief Creates a copy of the supplied BFile.
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If \a file is uninitialized, the newly constructed BFile will be too.
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\param file The BFile object to be copied.
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\since BeOS R3
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*/
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/*!
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\fn BFile::BFile(const entry_ref* ref, uint32 openMode)
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\brief Creates a BFile and initializes it to the file referred to by
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the supplied entry_ref and according to the specified open mode.
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\param ref The entry_ref referring to the file.
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\param openMode The mode in which the file should be opened.
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\see SetTo(const entry_ref* ref, uint32 openMode)
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\since BeOS R3
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*/
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/*!
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\fn BFile::BFile(const BEntry* entry, uint32 openMode)
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\brief Creates a BFile and initializes it to the file referred to by
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the supplied BEntry and according to the specified open mode.
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\param entry The BEntry referring to the file.
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\param openMode The mode in which the file should be opened.
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\see SetTo(const BEntry* entry, uint32 openMode)
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\since BeOS R3
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*/
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/*!
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\fn BFile::BFile(const char* path, uint32 openMode)
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\brief Creates a BFile and initializes it to the file referred to by
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the supplied path name and according to the specified open mode.
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\param path The file's path name.
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\param openMode The mode in which the file should be opened.
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\see SetTo(const char* path, uint32 openMode)
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\since BeOS R3
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*/
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/*!
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\fn BFile::BFile(const BDirectory *dir, const char* path, uint32 openMode)
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\brief Creates a BFile and initializes it to the file referred to by
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the supplied path name relative to the specified BDirectory and
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according to the specified open mode.
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\param dir The BDirectory, relative to which the file's path name is
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given.
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\param path The file's path name relative to \a dir.
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\param openMode The mode in which the file should be opened.
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\see SetTo(const BDirectory* dir, const char* path, uint32 openMode)
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\since BeOS R3
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*/
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/*!
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\fn BFile::~BFile()
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\brief Destroys the BFile object and frees all allocated resources.
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If the file is properly initialized, the file descriptor is closed.
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\since BeOS R3
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*/
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/*!
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\fn status_t BFile::SetTo(const entry_ref* ref, uint32 openMode)
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\brief Re-initializes the BFile to the file referred to by the
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supplied entry_ref and according to the specified open mode.
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\param ref The entry_ref referring to the file.
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\param openMode The mode in which the file should be opened
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\a openMode must be a bitwise or of exactly one of the flags.
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- \c B_READ_ONLY: The file is opened read only.
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- \c B_WRITE_ONLY: The file is opened write only.
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- \c B_READ_WRITE: The file is opened for random read/write access.
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and any number of the flags
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- \c B_CREATE_FILE: A new file will be created, if it does not
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already exist.
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- \c B_FAIL_IF_EXISTS: If the file does already exist and
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\c B_CREATE_FILE is set, SetTo() fails.
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- \c B_ERASE_FILE: An already existing file is truncated to zero
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size.
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- \c B_OPEN_AT_END: Seek() to the end of the file after opening.
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\returns A status code.
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\retval B_OK Everything went fine.
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\retval B_BAD_VALUE \c NULL \a ref or bad \a openMode.
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\retval B_ENTRY_NOT_FOUND File not found or failed to create file.
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\retval B_FILE_EXISTS File exists and \c B_FAIL_IF_EXISTS was passed.
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\retval B_PERMISSION_DENIED File permissions didn't allow operation.
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\retval B_NO_MEMORY Insufficient memory for operation.
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\retval B_LINK_LIMIT Indicates a cyclic loop within the file system.
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\retval B_BUSY A node was busy.
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\retval B_FILE_ERROR A general file error.
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\retval B_NO_MORE_FDS The application has run out of file descriptors.
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\since BeOS R3
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*/
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/*!
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\fn status_t BFile::SetTo(const BEntry* entry, uint32 openMode)
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\brief Re-initializes the BFile to the file referred to by the
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supplied BEntry and according to the specified open mode.
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\param entry the BEntry referring to the file
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\param openMode the mode in which the file should be opened
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\returns A status code.
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\retval B_OK Everything went fine.
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\retval B_BAD_VALUE \c NULL \a entry or bad \a openMode.
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\retval B_ENTRY_NOT_FOUND File not found or failed to create file.
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\retval B_FILE_EXISTS File exists and \c B_FAIL_IF_EXISTS was passed.
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\retval B_PERMISSION_DENIED File permissions didn't allow operation.
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\retval B_NO_MEMORY Insufficient memory for operation.
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\retval B_LINK_LIMIT Indicates a cyclic loop within the file system.
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\retval B_BUSY A node was busy.
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\retval B_FILE_ERROR A general file error.
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\retval B_NO_MORE_FDS The application has run out of file descriptors.
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\todo Implemented using SetTo(entry_ref*, uint32). Check, if necessary
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to re-implement!
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\since BeOS R3
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*/
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/*!
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\fn status_t BFile::SetTo(const char* path, uint32 openMode)
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\brief Re-initializes the BFile to the file referred to by the
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supplied path name and according to the specified open mode.
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\param path The file's path name.
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\param openMode The mode in which the file should be opened.
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\returns A status code.
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\retval B_OK Everything went fine.
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\retval B_BAD_VALUE \c NULL \a path or bad \a openMode.
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\retval B_ENTRY_NOT_FOUND File not found or failed to create file.
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\retval B_FILE_EXISTS File exists and \c B_FAIL_IF_EXISTS was passed.
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\retval B_PERMISSION_DENIED File permissions didn't allow operation.
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\retval B_NO_MEMORY Insufficient memory for operation.
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\retval B_LINK_LIMIT Indicates a cyclic loop within the file system.
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\retval B_BUSY A node was busy.
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\retval B_FILE_ERROR A general file error.
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\retval B_NO_MORE_FDS The application has run out of file descriptors.
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\since BeOS R3
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*/
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/*!
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\fn status_t BFile::SetTo(const BDirectory* dir, const char* path,
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uint32 openMode)
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\brief Re-initializes the BFile to the file referred to by the
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supplied path name relative to the specified BDirectory and
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according to the specified open mode.
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\param dir The BDirectory, relative to which the file's path name is
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given.
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\param path The file's path name relative to \a dir.
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\param openMode The mode in which the file should be opened.
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\returns A status code.
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\retval B_OK Everything went fine.
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\retval B_BAD_VALUE \c NULL \a dir or \a path or bad \a openMode.
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\retval B_ENTRY_NOT_FOUND File not found or failed to create file.
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\retval B_FILE_EXISTS File exists and \c B_FAIL_IF_EXISTS was passed.
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\retval B_PERMISSION_DENIED File permissions didn't allow operation.
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\retval B_NO_MEMORY Insufficient memory for operation.
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\retval B_LINK_LIMIT Indicates a cyclic loop within the file system.
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\retval B_BUSY A node was busy.
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\retval B_FILE_ERROR A general file error.
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\retval B_NO_MORE_FDS The application has run out of file descriptors.
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\todo Implemented using SetTo(BEntry*, uint32). Check, if necessary
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to re-implement!
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\since BeOS R3
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*/
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/*!
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\fn bool BFile::IsReadable() const
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\brief Reports whether or not the file is readable.
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\return
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- \c true, if the BFile has been initialized properly and the file has
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been been opened for reading,
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- \c false, otherwise.
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\since BeOS R3
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*/
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/*!
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\fn bool BFile::IsWritable() const
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\brief Reports whether or not the file is writable.
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\return
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- \c true, if the BFile has been initialized properly and the file has
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been opened for writing,
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- \c false, otherwise.
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\since BeOS R3
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*/
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/*!
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ssize_t BFile::Read(void* buffer, size_t size)
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\brief Reads a number of bytes from the file into a buffer.
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\param buffer The buffer the data from the file shall be written to.
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\param size The number of bytes that shall be read.
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\returns The number of bytes read or an error code.
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\since BeOS R3
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*/
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/*!
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\fn ssize_t BFile::ReadAt(off_t location, void* buffer, size_t size)
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\brief Reads a number of bytes from a certain position within the file
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into a buffer.
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\param location The position (in bytes) within the file from which the
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data shall be read.
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\param buffer The buffer the data from the file shall be written to.
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\param size The number of bytes that shall be read.
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\returns The number of bytes read or an error code.
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\since BeOS R3
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*/
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/*!
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\fn ssize_t BFile::Write(const void* buffer, size_t size)
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\brief Writes a number of bytes from a buffer into the file.
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\param buffer The buffer containing the data to be written to the file.
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\param size The number of bytes that shall be written.
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\returns The number of bytes actually written or an error code.
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\since BeOS R3
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*/
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/*!
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\fn ssize_t BFile::WriteAt(off_t location, const void* buffer, size_t size)
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\brief Writes a number of bytes from a buffer at a certain position
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into the file.
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\param location The position (in bytes) within the file at which the data
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shall be written.
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\param buffer The buffer containing the data to be written to the file.
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\param size The number of bytes that shall be written.
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\returns The number of bytes actually written or an error code.
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\since BeOS R3
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*/
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/*!
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\fn off_t BFile::Seek(off_t offset, uint32 seekMode)
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\brief Seeks to another read/write position within the file.
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It is allowed to seek past the end of the file. A subsequent call to
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Write() will pad the file with undefined data. Seeking before the
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beginning of the file will fail and the behavior of subsequent Read()
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or Write() invocations will be undefined.
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\param offset New read/write position, depending on \a seekMode relative
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to the beginning or the end of the file or the current position.
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\param seekMode
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- \c SEEK_SET: move relative to the beginning of the file.
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- \c SEEK_CUR: move relative to the current position.
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- \c SEEK_END: move relative to the end of the file.
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\returns The new read/write position relative to the beginning of the
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file or an error code.
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\retval B_ERROR Trying to seek before the beginning of the file.
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\retval B_FILE_ERROR The file is not properly initialized.
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\since BeOS R3
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*/
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/*!
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\fn off_t BFile::Position() const
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\brief Gets the current read/write position within the file.
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\returns The current read/write position relative to the beginning of the
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file or an error code.
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\retval B_ERROR After a Seek() before the beginning of the file.
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\retval B_FILE_ERROR The file has not been initialized.
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\since BeOS R3
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*/
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/*!
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\fn status_t BFile::SetSize(off_t size)
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\brief Sets the size of the file.
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If the file is shorter than \a size bytes it will be padded with
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unspecified data to the requested size. If it is larger, it will be
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truncated.
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\note There's no problem with setting the size of a BFile opened in
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\c B_READ_ONLY mode, unless the file resides on a read only volume.
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\param size The new file size.
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\returns A status code.
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\retval B_OK Everything went fine.
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\retval B_NOT_ALLOWED Trying to set the size of a file on a read only
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volume.
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\retval B_DEVICE_FULL There's not enough space left on the volume.
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\since BeOS R3
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*/
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/*!
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\fn status_t BFile::GetSize(off_t* size) const
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\brief Gets the size of the file.
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\param size The file size to fill out.
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\returns A status code.
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\see BStatable::GetSize()
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\since BeOS R3
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*/
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/*!
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\fn BFile& BFile::operator=(const BFile &file)
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\brief Assigns another BFile to this BFile.
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If the other BFile is uninitialized, this one will be too. Otherwise it
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will refer to the same file using the same mode, unless an error occurs.
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\param file The original BFile to assign from.
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\returns A reference to the assigned BFile.
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\since BeOS R3
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*/
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