tasks_file.h

This library provides assynchronous file operations. It uses STask to execute the synchronous operations from interface/file.h in a seperate thread.

File information

File	common/lib/tasks_file.h
Classes	TaskFileWrite TaskFileRead

Classes

TaskFileWrite

Used to write to a file. A file may be created, an existing file replaced or to an existing file appended.

class TaskFileWrite : public STask {
    void SStart();

    char * workingPath;
    char * fileName;
    bool append;
    class IFileWrite * file;
    byte * buffer;
    unsigned length;
    bool last;

public:
    TaskFileWrite(class STaskContext * context, const char * workingPath, const char * fileName, bool append);
    ~TaskFileWrite();

    void write(byte * buffer, unsigned length, bool last);
    void writeBuffer(byte * buffer, unsigned length, bool last);
};

TaskFileWrite

Contructor. TaskFileWrite uses STask as base class, which means for the operation, first the class is allocated with all required parameters and then SStart() is used to start it. The TaskProgress, TaskComplete and TaskFailed functions are used to indicate progress and completion of the Task.

Parameters

class STaskContext * context	An STaskContext must be allocated for the operation. It manages a pool of threads for the execution.
const char * workingPath	The path in which the file is written. If parts of the path do not exist the folders are created.
const char * fileName	The name of the file to be written. If the file does not exist, it is created.
bool append	If true the data is appended to the file, if it already exists, otherwise the file is overwritten

write

Write data to the file. May be called after the TaskProgress callback was called, either after SStart() or the last write() call. The data passed by this function is copied into a new buffer.

Parameters

byte * buffer	Buffer containing the data
unsigned length	The length of the data in bytes
bool last	Indicates that this is the last block of data. The operation completes when this parameter is set to true

writeBuffer

Same functionality as write, except the data is not copied and the buffer is freed after the data is written.

TaskFileRead

Used to read from a file.

class TaskFileRead : public STask {
    void SStart();

    char * workingPath;
    char * fileName;
    class IFileRead * file;
    byte * buffer;
    unsigned length;
    bool last;
public:
    TaskFileRead(class STaskContext * context, const char * workingPath, const char * fileName, unsigned length, bool last);
    ~TaskFileRead();

    void read(unsigned length, bool last);
    unsigned getLength() { return length; };
    void getData(byte * buffer, unsigned length) { memcpy(buffer, this->buffer, length); };
};

TaskFileRead

Contructor. TaskFileRead uses STask as base class, which means for the operation, first the class is allocated with all required parameters and then SStart() is used to start it. The TaskProgress, TaskComplete and TaskFailed functions are used to indicate progress and completion of the Task.

Parameters

class STaskContext * context	An STaskContext must be allocated for the operation. It manages a pool of threads for the execution.
const char * workingPath	The path from which the file is read
const char * fileName	The name of the file to be read.
unsigned length	The length to be read initially
bool last	If true no othe data shall be read after the initial block.

read

Initiates reading of the next block of data. May be called after the TaskProgress callback was called, either after SStart() or the last read() call.

Parameters

unsigned length	The length to be read initially
bool last	If true no othe data shall be read after the initial block.

getLength

Return the actual read length after the TaskProgress call

getData

Copies the read data.

Parameters

byte * buffer	The buffer the data is copied to.
unsigned length	The length to be copied.