java.lang.Object
- java.io.InputStream
- - com.alibaba.graphscope.serialization.FakeFFIByteVectorInputStream

All Implemented Interfaces:

Closeable, DataInput, AutoCloseable
```
public class FakeFFIByteVectorInputStream
extends InputStream
implements DataInput
```
FFIByteVectorInput stream wrap a byte vector as a stream. One stream can accept appended bytes. We use one read offset to mark from where we start reading and read limit to mark how many bytes we can read.

Constructor Summary

Constructors
Constructor Description

FakeFFIByteVectorInputStream(FakeFFIByteVector vector)
When Use vector to initialize a input stream, we assume it is compact, i.e.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`int`	`available()`
`void`	`clear()`
`long`	`longAvailable()`
`int`	`read()`	Reads the next byte of data from the input stream.
`int`	`read(byte[] b)`
`int`	`read(byte[] b, int off, int len)`
`int`	`read(char[] b, int off, int len)`
`boolean`	`readBoolean()`	Reads one input byte and returns `true` if that byte is nonzero, `false` if that byte is zero.
`byte`	`readByte()`	Reads and returns one input byte.
`char`	`readChar()`	Reads two input bytes and returns a `char` value.
`double`	`readDouble()`	Reads eight input bytes and returns a `double` value.
`float`	`readFloat()`	Reads four input bytes and returns a `float` value.
`void`	`readFully(byte[] b)`	Reads some bytes from an input stream and stores them into the buffer array `b`.
`void`	`readFully(byte[] b, int off, int len)`	Reads `len` bytes from an input stream.
`int`	`readInt()`	Reads four input bytes and returns an `int` value.
`String`	`readLine()`	Reads the next line of text from the input stream.
`long`	`readLong()`	Reads eight input bytes and returns a `long` value.
`short`	`readShort()`	Reads two input bytes and returns a `short` value.
`int`	`readUnsignedByte()`	Reads one input byte, zero-extends it to type `int`, and returns the result, which is therefore in the range `0` through `255`.
`int`	`readUnsignedShort()`	Reads two input bytes and returns an `int` value in the range `0` through `65535`.
`String`	`readUTF()`	Reads in a string that has been encoded using a modified UTF-8 format.
`void`	`reset()`	Reset to the first pos.
`int`	`skipBytes(int n)`	Makes an attempt to skip over `n` bytes of data from the input stream, discarding the skipped bytes.

Methods inherited from class java.io.InputStream
close, mark, markSupported, nullInputStream, readAllBytes, readNBytes, readNBytes, skip, transferTo

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - FakeFFIByteVectorInputStream
```
public FakeFFIByteVectorInputStream(FakeFFIByteVector vector)
```
    When Use vector to initialize a input stream, we assume it is compact, i.e. vector.size == readableBytes.
    
    Parameters:
    
    vector - vector to use.
- Method Detail
  - reset
```
public void reset()
```
    Reset to the first pos. byte still readable.
    
    Overrides:
    
    reset in class InputStream
  - clear
```
public void clear()
```
  - readFully
```
public void readFully(byte[] b)
               throws IOException
```
    Reads some bytes from an input stream and stores them into the buffer array b. The number of bytes read is equal to the length of b.
    This method blocks until one of the following conditions occurs:
    
    b.length bytes of input data are available, in which case a normal return is made.
    End of file is detected, in which case an EOFException is thrown.
    An I/O error occurs, in which case an IOException other than EOFException is thrown.
    
    If b is null, a NullPointerException is thrown. If b.length is zero, then no bytes are read. Otherwise, the first byte read is stored into element b[0], the next one into b[1], and so on. If an exception is thrown from this method, then it may be that some but not all bytes of b have been updated with data from the input stream.
    Specified by:
    
    readFully in interface DataInput
    
    Parameters:
    
    b - the buffer into which the data is read.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - readFully
```
public void readFully(byte[] b,
                      int off,
                      int len)
               throws IOException
```
    Reads len bytes from an input stream.
    This method blocks until one of the following conditions occurs:
    
    len bytes of input data are available, in which case a normal return is made.
    End of file is detected, in which case an EOFException is thrown.
    An I/O error occurs, in which case an IOException other than EOFException is thrown.
    
    If b is null, a NullPointerException is thrown. If off is negative, or len is negative, or off+len is greater than the length of the array b, then an IndexOutOfBoundsException is thrown. If len is zero, then no bytes are read. Otherwise, the first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len.
    Specified by:
    
    readFully in interface DataInput
    
    Parameters:
    
    b - the buffer into which the data is read.
    
    off - an int specifying the offset into the data.
    
    len - an int specifying the number of bytes to read.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - skipBytes
```
public int skipBytes(int n)
              throws IOException
```
    Makes an attempt to skip over n bytes of data from the input stream, discarding the skipped bytes. However, it may skip over some smaller number of bytes, possibly zero. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. This method never throws an EOFException. The actual number of bytes skipped is returned.
    
    Specified by:
    
    skipBytes in interface DataInput
    
    Parameters:
    
    n - the number of bytes to be skipped.
    
    Returns:
    
    the number of bytes actually skipped.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - readBoolean
```
public boolean readBoolean()
                    throws IOException
```
    Reads one input byte and returns true if that byte is nonzero, false if that byte is zero. This method is suitable for reading the byte written by the writeBoolean method of interface DataOutput.
    
    Specified by:
    
    readBoolean in interface DataInput
    
    Returns:
    
    the boolean value read.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - readByte
```
public byte readByte()
              throws IOException
```
    Reads and returns one input byte. The byte is treated as a signed value in the range -128 through 127, inclusive. This method is suitable for reading the byte written by the writeByte method of interface DataOutput.
    
    Specified by:
    
    readByte in interface DataInput
    
    Returns:
    
    the 8-bit value read.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - readUnsignedByte
```
public int readUnsignedByte()
                     throws IOException
```
    Reads one input byte, zero-extends it to type int, and returns the result, which is therefore in the range 0 through 255. This method is suitable for reading the byte written by the writeByte method of interface DataOutput if the argument to writeByte was intended to be a value in the range 0 through 255.
    
    Specified by:
    
    readUnsignedByte in interface DataInput
    
    Returns:
    
    the unsigned 8-bit value read.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - readShort
```
public short readShort()
                throws IOException
```
    Reads two input bytes and returns a short value. Let a be the first byte read and b be the second byte. The value returned is:
    (short)((a << 8) | (b & 0xff))
    
    This method is suitable for reading the bytes written by the writeShort method of interface DataOutput.
    Specified by:
    
    readShort in interface DataInput
    
    Returns:
    
    the 16-bit value read.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - readUnsignedShort
```
public int readUnsignedShort()
                      throws IOException
```
    Reads two input bytes and returns an int value in the range 0 through 65535. Let a be the first byte read and b be the second byte. The value returned is:
    (((a & 0xff) << 8) | (b & 0xff))
    
    This method is suitable for reading the bytes written by the writeShort method of interface DataOutput if the argument to writeShort was intended to be a value in the range 0 through 65535.
    Specified by:
    
    readUnsignedShort in interface DataInput
    
    Returns:
    
    the unsigned 16-bit value read.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - readChar
```
public char readChar()
              throws IOException
```
    Reads two input bytes and returns a char value. Let a be the first byte read and b be the second byte. The value returned is:
    (char)((a << 8) | (b & 0xff))
    
    This method is suitable for reading bytes written by the writeChar method of interface DataOutput.
    Specified by:
    
    readChar in interface DataInput
    
    Returns:
    
    the char value read.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - readInt
```
public int readInt()
            throws IOException
```
    Reads four input bytes and returns an int value. Let a-d be the first through fourth bytes read. The value returned is:
    (((a & 0xff) << 24) | ((b & 0xff) << 16) | ((c & 0xff) << 8) | (d & 0xff))
    
    This method is suitable for reading bytes written by the writeInt method of interface DataOutput.
    Specified by:
    
    readInt in interface DataInput
    
    Returns:
    
    the int value read.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - readLong
```
public long readLong()
              throws IOException
```
    Reads eight input bytes and returns a long value. Let a-h be the first through eighth bytes read. The value returned is:
    (((long)(a & 0xff) << 56) | ((long)(b & 0xff) << 48) | ((long)(c & 0xff) << 40) | ((long)(d & 0xff) << 32) | ((long)(e & 0xff) << 24) | ((long)(f & 0xff) << 16) | ((long)(g & 0xff) << 8) | ((long)(h & 0xff)))
    
    This method is suitable for reading bytes written by the writeLong method of interface DataOutput.
    Specified by:
    
    readLong in interface DataInput
    
    Returns:
    
    the long value read.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - readFloat
```
public float readFloat()
                throws IOException
```
    Reads four input bytes and returns a float value. It does this by first constructing an int value in exactly the manner of the readInt method, then converting this int value to a float in exactly the manner of the method Float.intBitsToFloat. This method is suitable for reading bytes written by the writeFloat method of interface DataOutput.
    
    Specified by:
    
    readFloat in interface DataInput
    
    Returns:
    
    the float value read.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - readDouble
```
public double readDouble()
                  throws IOException
```
    Reads eight input bytes and returns a double value. It does this by first constructing a long value in exactly the manner of the readLong method, then converting this long value to a double in exactly the manner of the method Double.longBitsToDouble. This method is suitable for reading bytes written by the writeDouble method of interface DataOutput.
    
    Specified by:
    
    readDouble in interface DataInput
    
    Returns:
    
    the double value read.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - readLine
```
public String readLine()
                throws IOException
```
    Reads the next line of text from the input stream. It reads successive bytes, converting each byte separately into a character, until it encounters a line terminator or end of file; the characters read are then returned as a String. Note that because this method processes bytes, it does not support input of the full Unicode character set.
    If end of file is encountered before even one byte can be read, then null is returned. Otherwise, each byte that is read is converted to type char by zero-extension. If the character '\n' is encountered, it is discarded and reading ceases. If the character '\r' is encountered, it is discarded and, if the following byte converts to the character '\n', then that is discarded also; reading then ceases. If end of file is encountered before either of the characters '\n' and '\r' is encountered, reading ceases. Once reading has ceased, a String is returned that contains all the characters read and not discarded, taken in order. Note that every character in this string will have a value less than \u0100, that is, (char)256.
    
    Specified by:
    
    readLine in interface DataInput
    
    Returns:
    
    the next line of text from the input stream, or null if the end of file is encountered before a byte can be read.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - readUTF
```
public String readUTF()
               throws IOException
```
    Reads in a string that has been encoded using a modified UTF-8 format. The general contract of readUTF is that it reads a representation of a Unicode character string encoded in modified UTF-8 format; this string of characters is then returned as a String.
    First, two bytes are read and used to construct an unsigned 16-bit integer in exactly the manner of the readUnsignedShort method . This integer value is called the UTF length and specifies the number of additional bytes to be read. These bytes are then converted to characters by considering them in groups. The length of each group is computed from the value of the first byte of the group. The byte following a group, if any, is the first byte of the next group.
    If the first byte of a group matches the bit pattern 0xxxxxxx (where x means "may be 0 or 1"), then the group consists of just that byte. The byte is zero-extended to form a character.
    If the first byte of a group matches the bit pattern 110xxxxx, then the group consists of that byte a and a second byte b. If there is no byte b (because byte a was the last of the bytes to be read), or if byte b does not match the bit pattern 10xxxxxx, then a UTFDataFormatException is thrown. Otherwise, the group is converted to the character:
    (char)(((a & 0x1F) << 6) | (b & 0x3F))
    
    If the first byte of a group matches the bit pattern 1110xxxx, then the group consists of that byte a and two more bytes b and c. If there is no byte c (because byte a was one of the last two of the bytes to be read), or either byte b or byte c does not match the bit pattern 10xxxxxx, then a UTFDataFormatException is thrown. Otherwise, the group is converted to the character:
    (char)(((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F))
    
    If the first byte of a group matches the pattern 1111xxxx or the pattern 10xxxxxx, then a UTFDataFormatException is thrown.
    If end of file is encountered at any time during this entire process, then an EOFException is thrown.
    After every group has been converted to a character by this process, the characters are gathered, in the same order in which their corresponding groups were read from the input stream, to form a String, which is returned.
    The writeUTF method of interface DataOutput may be used to write data that is suitable for reading by this method.
    Specified by:
    
    readUTF in interface DataInput
    
    Returns:
    
    a Unicode string.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
    
    UTFDataFormatException - if the bytes do not represent a valid modified UTF-8 encoding of a string.
  - read
```
public int read()
         throws IOException
```
    Reads the next byte of data from the input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.
    A subclass must provide an implementation of this method.
    
    Specified by:
    
    read in class InputStream
    
    Returns:
    
    the next byte of data, or -1 if the end of the stream is reached.
    
    Throws:
    
    IOException - if an I/O error occurs.
  - read
```
public final int read(byte[] b)
               throws IOException
```
    Overrides:
    
    read in class InputStream
    
    Throws:
    
    IOException
  - read
```
public int read(byte[] b,
                int off,
                int len)
         throws IOException
```
    Overrides:
    
    read in class InputStream
    
    Throws:
    
    IOException
  - read
```
public int read(char[] b,
                int off,
                int len)
         throws IOException
```
    Throws:
    
    IOException
  - available
```
public int available()
              throws IOException
```
    Overrides:
    
    available in class InputStream
    
    Throws:
    
    IOException
  - longAvailable
```
public long longAvailable()
```

Class FakeFFIByteVectorInputStream

Constructor Summary

Method Summary

Methods inherited from class java.io.InputStream

Methods inherited from class java.lang.Object

Constructor Detail

FakeFFIByteVectorInputStream

Method Detail

reset

clear

readFully

readFully

skipBytes

readBoolean

readByte

readUnsignedByte

readShort

readUnsignedShort

readChar

readInt

readLong

readFloat

readDouble

readLine

readUTF

read

read

read

read

available

longAvailable