ObjectRangeStream

Range query stream reading object

RangeStream objects are used toSeekableStreamObject data is intercepted. Creation method:

1
2
3
4
5
var stm = new io.RangeStream(stream, '0-10');
stm.end // 11

var stm = new io.RangeStream(stream, 0, 10);
stm.end // 10

inheritance relationship

Constructor

RangeStream

RangeStream constructor

1
2
new RangeStream(SeekableStream stm,
    String range);

Call parameters:

• stm:SeekableStream, the binary underlying stream object of RangeStream, must beSeekableStream
• range: String, a string describing the range, in the format of 'begin-[end]', '[begin]-end'

---

RangeStream constructor

1
2
3
new RangeStream(SeekableStream stm,
    Long begin,
    Long end);

Call parameters:

• stm:SeekableStream, the binary underlying stream object of RangeStream, must beSeekableStream
• begin: Long, the starting position of the content read from stm
• end: Long, the end position of the content read from stm

member properties

begin

Long, query the starting value of range

1
readonly Long RangeStream.begin;

---

end

Long, query range end value

1
readonly Long RangeStream.end;

---

fd

Integer, queryStreamThe corresponding file descriptor value, implemented by subclasses

1
readonly Integer RangeStream.fd;

member function

seek

Move the current file operation location

1
2
RangeStream.seek(Long offset,
    Integer whence = fs.SEEK_SET);

Call parameters:

• offset: Long, specify the new location
• whence: Integer, specifies the position reference, allowed values ​​are: SEEK_SET, SEEK_CUR, SEEK_END

---

tell

Query the current position of the stream

1
Long RangeStream.tell();

Return results:

• Long, returns the current position of the stream

---

rewind

Move the current position to the beginning of the stream

1
RangeStream.rewind();

---

size

Query stream size

1
Long RangeStream.size();

Return results:

• Long, returns the stream size

---

readAll

Read all remaining data from the stream

1
Buffer RangeStream.readAll() async;

Return results:

• Buffer, returns the data read from the stream. If there is no data to read or the connection is interrupted, null is returned.

---

truncate

Modify the file size. If the new size is smaller than the original size, the file will be truncated.

1
RangeStream.truncate(Long bytes) async;

Call parameters:

• bytes: Long, new file size

---

eof

Query whether the file reaches the end

1
Boolean RangeStream.eof();

Return results:

• Boolean, returns True to indicate the end

---

stat

Query basic information of the current file

1
Stat RangeStream.stat() async;

Return results:

• Stat, returnStatObject description file information

---

read

Read data of specified size from the stream

1
Buffer RangeStream.read(Integer bytes = -1) async;

Call parameters:

• bytes: Integer, specifies the amount of data to be read. The default is to read data blocks of random size. The size of the data read depends on the device.

Return results:

• Buffer, returns the data read from the stream. If there is no data to read or the connection is interrupted, null is returned.

---

write

Write the given data to the stream

1
RangeStream.write(Buffer data) async;

Call parameters:

• data:Buffer, given the data to be written

---

flush

Write file buffer contents to physical device

1
RangeStream.flush() async;

---

close

Close the current stream object

1
RangeStream.close() async;

---

copyTo

Copy stream data to target stream

1
2
Long RangeStream.copyTo(Stream stm,
    Long bytes = -1) async;

Call parameters:

• stm:Stream, target stream object
• bytes: Long, number of bytes copied

Return results:

• Long, returns the number of bytes copied

---

toString

Returns the string representation of the object. Generally, "[Native Object]" is returned. The object can be re-implemented according to its own characteristics.

1
String RangeStream.toString();

Return results:

• String, returns the string representation of the object

---

toJSON

Returns a JSON format representation of the object, generally returning a collection of readable properties defined by the object.

1
Value RangeStream.toJSON(String key = "");

Call parameters:

• key: String, not used

Return results:

• Value, returns a value containing JSON serializable