//Write data into an open file.
//file: The file handle.
//buffer: The data.
//length: The no. of bytes to write.
//Returns the number of bytes written; or error.
func (fs *Fs) Write(file *File, buffer []byte, length int) (uint32, error) {
file.Lock()
defer file.Unlock()
ret, err := C.hdfsWrite(fs.cptr, file.cptr, (unsafe.Pointer(&buffer[0])), C.tSize(length))
if err != nil && ret == C.tSize(-1) {
return 0, err
}
return uint32(ret), nil
}
//Positional read of data from an open file.
//file: The file handle.
//position: Position from which to read.
//buffer: The buffer to copy read bytes into.
//length: The length of the buffer.
//Returns the number of bytes actually read, possibly less than length; or error.
func (fs *Fs) Pread(file *File, position int64, buffer []byte, length int) (uint32, error) {
file.RLock()
defer file.RUnlock()
ret, err := C.hdfsPread(fs.cptr, file.cptr, C.tOffset(position), (unsafe.Pointer(&buffer[0])), C.tSize(length))
if err != nil && ret == C.tSize(-1) {
return 0, err
}
return uint32(ret), nil
}
//Open a hdfs file in given mode.
//path: The full path to the file.
//flags: - an | of bits/fcntl.h file flags - supported flags are O_RDONLY, O_WRONLY (meaning create or overwrite i.e., implies O_TRUNCAT), O_WRONLY|O_APPEND. Other flags are generally ignored other than (O_RDWR || (O_EXCL & O_CREAT)) which return nil and set error equal ENOTSUP.
//bufferSize: Size of buffer for read/write - pass 0 if you want to use the default configured values.
//replication: Block replication - pass 0 if you want to use the default configured values.
//blocksize: Size of block - pass 0 if you want to use the default configured values.
//Returns the handle to the open file or nil on error.
func (fs *Fs) OpenFile(path string, flags int, buffersize int, replication int, blocksize uint32) (*File, error) {
p := C.CString(path)
defer C.free(unsafe.Pointer(p))
file, err := C.hdfsOpenFile(fs.cptr, p, C.int(flags), C.int(buffersize), C.short(replication), C.tSize(blocksize))
if err != nil && file == (C.hdfsFile)(unsafe.Pointer(uintptr(0))) {
return nil, err
}
return &File{file, new(sync.RWMutex)}, nil
}