Provides random access to a file. More...

Public Member Functions
	FileContents (const File &file)
	Constructor.
	~FileContents ()
	Destructor.
uint64_t	getFileLength ()
	Return the length of the file.
void	copy (uint64_t offset, void *buf, uint64_t length)
	Copy some number of bytes of the file into a user-supplied buffer.
uint64_t	copyPartial (uint64_t offset, void *buf, uint64_t maxLength)
	Copy up to some number of bytes of the file into a user-supplied buffer.
template<typename T = void>
const T *	get (uint64_t offset, uint64_t length)
	Get a pointer to a region of the file.
Private Member Functions
const void *	getHelper (uint64_t offset, uint64_t length)
	Used internally by get().
	FileContents (const FileContents &)
FileContents &	operator= (const FileContents &)
Private Attributes
File	file
	An open file descriptor for the file to read.
uint64_t	fileLen
	The number of bytes in the file.
const void *	map
	The value returned by mmap(), or NULL for empty files.

Detailed Description

Provides random access to a file.

This implementation currently works by mmaping the file and working from the in-memory copy.

Definition at line 284 of file FilesystemUtil.h.

Constructor & Destructor Documentation

LogCabin::Storage::FilesystemUtil::FileContents::FileContents ( const File & file ) [explicit]

Constructor.

Parameters:

file	An open file descriptor for the file to read.

Definition at line 445 of file FilesystemUtil.cc.

LogCabin::Storage::FilesystemUtil::FileContents::~FileContents ( )

Destructor.

Definition at line 460 of file FilesystemUtil.cc.

LogCabin::Storage::FilesystemUtil::FileContents::FileContents ( const FileContents & ) [private]

uint64_t LogCabin::Storage::FilesystemUtil::FileContents::getFileLength ( ) [inline]

Return the length of the file.

Definition at line 297 of file FilesystemUtil.h.

void LogCabin::Storage::FilesystemUtil::FileContents::copy	(	uint64_t	offset,
		void *	buf,
		uint64_t	length
	)

Copy some number of bytes of the file into a user-supplied buffer.

If there are not enough bytes in the file, this will PANIC. See copyPartial if that's not what you want.

Parameters:

	offset	The number of bytes into the file at which to start copying.
[out]	buf	The destination buffer to copy into.
	length	The number of bytes to copy.

Definition at line 471 of file FilesystemUtil.cc.

uint64_t LogCabin::Storage::FilesystemUtil::FileContents::copyPartial	(	uint64_t	offset,
		void *	buf,
		uint64_t	maxLength
	)

Copy up to some number of bytes of the file into a user-supplied buffer.

Parameters:

	offset	The number of bytes into the file at which to start copying.
[out]	buf	The destination buffer to copy into.
	maxLength	The maximum number of bytes to copy.

Returns:: The number of bytes copied. This can be fewer than maxLength if the file ended first.

Definition at line 480 of file FilesystemUtil.cc.

template<typename T = void>

const T* LogCabin::Storage::FilesystemUtil::FileContents::get	(	uint64_t	offset,
		uint64_t	length
	)		`[inline]`

Get a pointer to a region of the file.

If there are not enough bytes in the file, this will PANIC.

Template Parameters:

T	The return type is casted to a pointer of T.

Parameters:

offset	The number of bytes into the file at which to return the pointer.
length	The number of bytes that must be valid after the offset.

Returns:: A pointer to a buffer containing the 'length' bytes starting at 'offset' in the file. The caller may not modify this buffer. The returned buffer will remain valid until this object is destroyed.

Definition at line 347 of file FilesystemUtil.h.