FileHelperRK Class Reference

Class to perform common file operations. More...

#include <FileHelperRK.h>

Data Structures
class	FileStreamBase
	Class for providing Stream and Print object for reading or writing a file. More...
class	FileStreamRead
	Class for reading from a file as a Stream. More...
class	FileStreamWrite
	Class for writing to a file as a Print. More...
class	ParsedPath
	Container for a parsed pathname (Unix-style, with slashes) More...
class	Usage
	Measure file system usage. More...
struct	WalkParameters
	Structure to hold the parameters to the walk method. More...

Static Public Member Functions
static int	mkdirs (const char *path)
	Create all of the directories in path.
static int	deleteRecursive (const char *path, bool contentsOfPathOnly=false)
	Delete a directory and all of the subdirectories and files.
static int	storeBytes (const char *fileName, const uint8_t *dataPtr, size_t dataLen)
	Store bytes to a file.
static int	storeString (const char *fileName, const String &data)
	Store a String object to a file.
static int	storeString (const char *fileName, const char *str)
	Store a c-string to a file.
template<typename T >
static const T &	storeStruct (const char *fileName, const T &t)
	Store a struct in a file.
static int	readBytes (const char *fileName, uint8_t *&dataPtr, size_t &dataLen, bool nullTerminate=false)
	Read bytes from a file.
static int	readBytesNoAlloc (const char *fileName, uint8_t *dataPtr, size_t &dataLen)
	Read bytes from a file into a buffer instead of allocating one.
static int	readString (const char *fileName, String &result)
	Read file contents to a String object.
template<typename T >
static T &	readStruct (const char *fileName, T &t)
	Read file contents to a struct.
static int	errnoToSystemError ()
	Internal function to convert the value of errno into a Particle system error code.
static String	pathJoin (const char *a, const char *b)
	Join two pathnames or filenames, adding a / delimeter in between if necessary.
static int	walk (const char *path, std::function< void(const WalkParameters &walkParameters)> cb)
	Walk the file system calling the callback function or lambda.

Static Public Attributes
static const char *	pathDelim = "/"
	Path delimeter ("/")

Detailed Description

Class to perform common file operations.

License: MIT (can use in free or commercial open or closed source products) Repository: https://github.com/rickkas7/FileHelperRK

Member Function Documentation

deleteRecursive()

int FileHelperRK::deleteRecursive ( const char * path, bool contentsOfPathOnly = false )

static

Delete a directory and all of the subdirectories and files.

Parameters

path	The directory (or contents of the directory) to delete
contentsOfPathOnly	If true, only delete the contents of path, leaving the top directory.

Returns

int SYSTEM_ERROR_NONE (0) on success or a system error code (non-zero)

errnoToSystemError()

int FileHelperRK::errnoToSystemError ( )

static

Internal function to convert the value of errno into a Particle system error code.

Returns

int A system_error_t error code (0 = success, negative value on error)

File system errors are only defined in Device OS 5.5.0 and later. If targeting an earlier version of Device OS, returns SYSTEM_ERROR_UNKNOWN.

mkdirs()

int FileHelperRK::mkdirs ( const char * path )

static

Create all of the directories in path.

Parameters

path

Returns

int SYSTEM_ERROR_NONE (0) on success or a system error code (non-zero)

The standard mkdir() function only will create the last component of the path.

pathJoin()

String FileHelperRK::pathJoin ( const char * a, const char * b )

static

Join two pathnames or filenames, adding a / delimeter in between if necessary.

Parameters

a	Path component(s). Can be slash separated parts, a filename, an empty string, or NULL.
b	Path component(s). Can be slash separated parts, a filename, an empty string, or NULL.

Returns

String The combined pathname

readBytes()

int FileHelperRK::readBytes ( const char * fileName, uint8_t *& dataPtr, size_t & dataLen, bool nullTerminate = false )

static

Read bytes from a file.

Parameters

fileName	Filename to read from
dataPtr	Filled in with an allocated pointer containing the data
dataLen	On return, the length of the data in bytes
nullTerminate	Set to true to null-terminate the buffer. Default is false. If null terminated, the dataLen is the actual string length, not including the null terminator.

Returns

int SYSTEM_ERROR_NONE (0) on success or a system error code (non-zero)

If the returned value in dataPtr is non-zero, you must delete it using delete[] dataPtr.

readBytesNoAlloc()

int FileHelperRK::readBytesNoAlloc ( const char * fileName, uint8_t * dataPtr, size_t & dataLen )

static

Read bytes from a file into a buffer instead of allocating one.

Parameters

fileName	Filename to read from
dataPtr	Buffer filled in with up to dataLen bytes
dataLen	On entry, size of the buffer in dataPtr. On exit, number of bytes copied to dataPtr

Returns

int SYSTEM_ERROR_NONE (0) on success or a system error code (non-zero)

readString()

int FileHelperRK::readString ( const char * fileName, String & result )

static

Read file contents to a String object.

Parameters

fileName	Filename to read from
result	String object filled in with the data

Returns

int SYSTEM_ERROR_NONE (0) on success or a system error code (non-zero)

readStruct()

template<typename T >

static T & FileHelperRK::readStruct ( const char * fileName, T & t )

inlinestatic

Read file contents to a struct.

Template Parameters

T	The struct/class to read

Parameters

fileName	Filename to read from
t	The variable to read into

Returns

T& Returns t.

If the struct is larger than the file, the extra space is padded with 0 bytes. If the struct is smaller than the file, the extra bytes rae ignored. If an error occurs, the struct is filled with 0 bytes.

storeBytes()

int FileHelperRK::storeBytes ( const char * fileName, const uint8_t * dataPtr, size_t dataLen )

static

Store bytes to a file.

Parameters

fileName	Filename to write to. File will be created and truncated.
dataPtr	Pointer to binary data to write
dataLen	Length of data (0 or more bytes)

Returns

int SYSTEM_ERROR_NONE (0) on success or a system error code (non-zero)

See also storeString()

storeString() [1/2]

int FileHelperRK::storeString ( const char * fileName, const char * str )

static

Store a c-string to a file.

Parameters

fileName	Filename to write to. File will be created and truncated.
str	c-string to write. Can be an empty string or NULL to save an empty file.

Returns

int SYSTEM_ERROR_NONE (0) on success or a system error code (non-zero)

storeString() [2/2]

int FileHelperRK::storeString ( const char * fileName, const String & data )

static

Store a String object to a file.

Parameters

fileName	Filename to write to. File will be created and truncated.
data	String object to write. It only needs to remain valid until this method returns.

Returns

int SYSTEM_ERROR_NONE (0) on success or a system error code (non-zero)

storeStruct()

template<typename T >

static const T & FileHelperRK::storeStruct ( const char * fileName, const T & t )

inlinestatic

Store a struct in a file.

Template Parameters

T	The struct/class to read

Parameters

fileName	Filename to read from
t	The variable to write

Returns

const T& returns t that was passed in

The struct must be flat; embedded objects including String are not serialized and will not be saved and restored properly.

walk()

int FileHelperRK::walk ( const char * path, std::function< void(const WalkParameters &walkParameters)> cb )

static

Walk the file system calling the callback function or lambda.

Parameters

path	Path to start checking (can be file or directory)
cb	Callback function or lambda to call

Returns

int SYSTEM_ERROR_NONE (0) on success or a system error code (non-zero)

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The documentation for this class was generated from the following files:

• src/FileHelperRK.h
• src/FileHelperRK.cpp