BufferedDataInputStream (FITS API)

java.lang.Object
- java.io.InputStream
- - java.io.FilterInputStream
  - - java.io.BufferedInputStream
    - - nom.tam.util.BufferedDataInputStream

All Implemented Interfaces:

java.io.Closeable, java.io.DataInput, java.lang.AutoCloseable, ArrayDataInput, FitsIO
```
public class BufferedDataInputStream
extends java.io.BufferedInputStream
implements ArrayDataInput
```
This class is intended for high performance I/O in scientific applications. It combines the functionality of the BufferedInputStream and the DataInputStream as well as more efficient handling of arrays. This minimizes the number of method calls that are required to read data. Informal tests of this method show that it can be as much as 10 times faster than using a DataInputStream layered on a BufferedInputStream for writing large arrays. The performance gain on scalars or small arrays will be less but there should probably never be substantial degradation of performance.
Many new read calls are added to allow efficient reading off array data. The read(Object o) call provides for reading a primitive array of arbitrary type or dimensionality. There are also reads for each type of one dimensional array.
Note that there is substantial duplication of code to minimize method invocations. E.g., the floating point read routines read the data as integer values and then convert to float. However the integer code is duplicated rather than invoked. There has been considerable effort expended to ensure that these routines are efficient, but they could easily be superceded if an efficient underlying I/O package were ever delivered as part of the basic Java libraries. [This has subsequently happened with the NIO package and in an ideal universe these classes would be rewritten to take advantage of NIO.]
Testing and timing routines are provided in the nom.tam.util.test.BufferedFileTester class. Version 1.1: October 12, 2000: Fixed handling of EOF to return partially read arrays when EOF is detected. Version 1.2: July 20, 2009: Added handling of very large Object arrays. Additional work is required to handle very large arrays generally.

Field Summary
- Fields inherited from class java.io.BufferedInputStream
  buf, count, marklimit, markpos, pos
- Fields inherited from class java.io.FilterInputStream
  in
- Fields inherited from interface nom.tam.util.FitsIO
  BITS_OF_1_BYTE, BITS_OF_2_BYTES, BITS_OF_3_BYTES, BITS_OF_4_BYTES, BITS_OF_5_BYTES, BITS_OF_6_BYTES, BITS_OF_7_BYTES, BYTE_1_OF_LONG_MASK, BYTE_2_OF_LONG_MASK, BYTE_3_OF_LONG_MASK, BYTE_4_OF_LONG_MASK, BYTE_MASK, BYTES_IN_BOOLEAN, BYTES_IN_BYTE, BYTES_IN_CHAR, BYTES_IN_DOUBLE, BYTES_IN_FLOAT, BYTES_IN_INTEGER, BYTES_IN_LONG, BYTES_IN_SHORT, DEFAULT_BUFFER_SIZE, HIGH_INTEGER_MASK, INTEGER_MASK, SHORT_MASK, SHORT_OF_LONG_MASK

Constructor Summary

Constructors
Constructor and Description
`BufferedDataInputStream(java.io.InputStream o)` Create a BufferedInputStream based on an input stream.
`BufferedDataInputStream(java.io.InputStream o, int bufLength)` Create a BufferedInputStream based on a input stream with a specified buffer size.

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`int`	`read(boolean[] b)` Read an array of boolean's.
`int`	`read(boolean[] b, int start, int length)` Read a segment of an array of boolean's.
`int`	`read(byte[] obuf, int offset, int length)` Read a segment of an array of byte's.
`int`	`read(char[] c)` Read an array of char's.
`int`	`read(char[] c, int start, int length)` Read a segment of an array of char's.
`int`	`read(double[] d)` Read an array of double's.
`int`	`read(double[] d, int start, int length)` Read a segment of an array of double's.
`int`	`read(float[] f)` Read an array of float's.
`int`	`read(float[] f, int start, int length)` Read a segment of an array of float's.
`int`	`read(int[] i)` Read an array of int's.
`int`	`read(int[] i, int start, int length)` Read a segment of an array of int's.
`int`	`read(long[] l)` Read a segment of an array of long's.
`int`	`read(long[] l, int start, int length)` Read a segment of an array of long's.
`int`	`read(short[] s)` Read an array of short's.
`int`	`read(short[] s, int start, int length)` Read a segment of an array of short's.
`int`	`readArray(java.lang.Object o)` Deprecated.
`boolean`	`readBoolean()`
`byte`	`readByte()`
`char`	`readChar()`
`double`	`readDouble()`
`float`	`readFloat()`
`void`	`readFully(byte[] b)`
`void`	`readFully(byte[] b, int off, int len)` Read a buffer and signal an EOF if the requested elements cannot be read.
`int`	`readInt()`
`long`	`readLArray(java.lang.Object o)` Read an object.
`java.lang.String`	`readLine()` Deprecated. Use `BufferedReader` methods.
`long`	`readLong()`
`int`	`readPrimitiveArray(java.lang.Object o)` Deprecated. use `readLArray(Object)` instead
`short`	`readShort()`
`int`	`readUnsignedByte()`
`int`	`readUnsignedShort()`
`java.lang.String`	`readUTF()`
`void`	`skipAllBytes(int toSkip)` Skip the number of bytes.
`void`	`skipAllBytes(long toSkip)` Skip the number of bytes.
`int`	`skipBytes(int toSkip)`
`java.lang.String`	`toString()`

Methods inherited from class java.io.BufferedInputStream
available, close, mark, markSupported, read, reset, skip

Methods inherited from class java.io.FilterInputStream
read

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

Methods inherited from interface nom.tam.util.ArrayDataInput
mark, read, reset, skip

Methods inherited from interface nom.tam.util.FitsIO
close

- Constructor Detail
  - BufferedDataInputStream
```
public BufferedDataInputStream(java.io.InputStream o)
```
    Create a BufferedInputStream based on an input stream.
    
    Parameters:
    
    o - the input stream to use for reading.
  - BufferedDataInputStream
```
public BufferedDataInputStream(java.io.InputStream o,
                               int bufLength)
```
    Create a BufferedInputStream based on a input stream with a specified buffer size.
    
    Parameters:
    
    o - the input stream to use for reading.
    
    bufLength - the buffer length to use.
- Method Detail
  - read
```
public int read(boolean[] b)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read an array of boolean's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Parameters:
    
    b - array of boolean's.
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
  - read
```
public int read(boolean[] b,
                int start,
                int length)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read a segment of an array of boolean's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Parameters:
    
    b - array of boolean's.
    
    start - start index in the array
    
    length - number of array elements to read
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
  - read
```
public int read(byte[] obuf,
                int offset,
                int length)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read a segment of an array of byte's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Overrides:
    
    read in class java.io.BufferedInputStream
    
    Parameters:
    
    obuf - array of byte's.
    
    offset - start index in the array
    
    length - number of array elements to read
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
    
    See Also:
    
    ArrayDataInput.readFully(byte[], int, int)
  - read
```
public int read(char[] c)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read an array of char's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Parameters:
    
    c - array of char's.
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
  - read
```
public int read(char[] c,
                int start,
                int length)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read a segment of an array of char's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Parameters:
    
    c - array of char's.
    
    start - start index in the array
    
    length - number of array elements to read
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
  - read
```
public int read(double[] d)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read an array of double's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Parameters:
    
    d - array of double's.
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
  - read
```
public int read(double[] d,
                int start,
                int length)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read a segment of an array of double's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Parameters:
    
    d - array of double's.
    
    start - start index in the array
    
    length - number of array elements to read
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
  - read
```
public int read(float[] f)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read an array of float's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Parameters:
    
    f - array of float's.
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
  - read
```
public int read(float[] f,
                int start,
                int length)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read a segment of an array of float's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Parameters:
    
    f - array of float's.
    
    start - start index in the array
    
    length - number of array elements to read
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
  - read
```
public int read(int[] i)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read an array of int's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Parameters:
    
    i - array of int's.
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
  - read
```
public int read(int[] i,
                int start,
                int length)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read a segment of an array of int's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Parameters:
    
    i - array of int's.
    
    start - start index in the array
    
    length - number of array elements to read
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
  - read
```
public int read(long[] l)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read a segment of an array of long's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Parameters:
    
    l - array of long's.
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
  - read
```
public int read(long[] l,
                int start,
                int length)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read a segment of an array of long's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Parameters:
    
    l - array of long's.
    
    start - start index in the array
    
    length - number of array elements to read
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
  - read
```
public int read(short[] s)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read an array of short's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Parameters:
    
    s - array of short's.
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
  - read
```
public int read(short[] s,
                int start,
                int length)
         throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read a segment of an array of short's.
    
    Specified by:
    
    read in interface ArrayDataInput
    
    Parameters:
    
    s - array of short's.
    
    start - start index in the array
    
    length - number of array elements to read
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if one of the underlying read operations failed
  - readArray
```
@Deprecated
public int readArray(java.lang.Object o)
                          throws java.io.IOException
```
    Deprecated.
    
    Description copied from interface: ArrayDataInput
    
    Read a generic (possibly multidimensional) primitive array. An Object[] array is also a legal argument if each element of the array is a legal.
    The ArrayDataInput classes do not support String input since it is unclear how one would read in an Array of strings.
    
    Specified by:
    
    readArray in interface ArrayDataInput
    
    Parameters:
    
    o - A [multidimensional] primitive (or Object) array.
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if the underlying stream failed
  - readBoolean
```
public boolean readBoolean()
                    throws java.io.IOException
```
    Specified by:
    
    readBoolean in interface java.io.DataInput
    
    Throws:
    
    java.io.IOException
  - readByte
```
public byte readByte()
              throws java.io.IOException
```
    Specified by:
    
    readByte in interface java.io.DataInput
    
    Throws:
    
    java.io.IOException
  - readChar
```
public char readChar()
              throws java.io.IOException
```
    Specified by:
    
    readChar in interface java.io.DataInput
    
    Throws:
    
    java.io.IOException
  - readDouble
```
public double readDouble()
                  throws java.io.IOException
```
    Specified by:
    
    readDouble in interface java.io.DataInput
    
    Throws:
    
    java.io.IOException
  - readFloat
```
public float readFloat()
                throws java.io.IOException
```
    Specified by:
    
    readFloat in interface java.io.DataInput
    
    Throws:
    
    java.io.IOException
  - readFully
```
public void readFully(byte[] b)
               throws java.io.IOException
```
    Specified by:
    
    readFully in interface java.io.DataInput
    
    Throws:
    
    java.io.IOException
  - readFully
```
public void readFully(byte[] b,
                      int off,
                      int len)
               throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read a buffer and signal an EOF if the requested elements cannot be read. This differs from read(b,off,len) since that call will not signal and end of file unless no bytes can be read. However both of these routines will attempt to fill their buffers completely.
    
    Specified by:
    
    readFully in interface java.io.DataInput
    
    Specified by:
    
    readFully in interface ArrayDataInput
    
    Parameters:
    
    b - The input buffer.
    
    off - The requested offset into the buffer.
    
    len - The number of bytes requested.
    
    Throws:
    
    java.io.IOException
  - readInt
```
public int readInt()
            throws java.io.IOException
```
    Specified by:
    
    readInt in interface java.io.DataInput
    
    Throws:
    
    java.io.IOException
  - readLArray
```
public long readLArray(java.lang.Object o)
                throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Read an object. An EOF will be signaled if the object cannot be fully read. This version works even if the underlying data is more than 2 Gigabytes.
    
    Specified by:
    
    readLArray in interface ArrayDataInput
    
    Parameters:
    
    o - The object to be read. This object should be a primitive (possibly multi-dimensional) array.
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if the underlying stream failed
  - readLine
```
@Deprecated
public java.lang.String readLine()
                                      throws java.io.IOException
```
    Deprecated. Use BufferedReader methods.
    
    Emulate the deprecated DataInputStream.readLine() method. Originally we used the method itself, but Alan Brighton suggested using a java.io.BufferedReader to eliminate the deprecation warning. This was used for a long time, but more recently we noted that this doesn't work. We now use a simple method that largely ignores character encodings and only uses the "\n" as the line separator. This method is slow regardless. In the current version
    
    Specified by:
    
    readLine in interface java.io.DataInput
    
    Returns:
    
    The String read.
    
    Throws:
    
    java.io.IOException
  - readLong
```
public long readLong()
              throws java.io.IOException
```
    Specified by:
    
    readLong in interface java.io.DataInput
    
    Throws:
    
    java.io.IOException
  - readPrimitiveArray
```
@Deprecated
public int readPrimitiveArray(java.lang.Object o)
                                   throws java.io.IOException
```
    Deprecated. use readLArray(Object) instead
    
    This routine provides efficient reading of arrays of any primitive type. It is an error to invoke this method with an object that is not an array of some primitive type. Note that there is no corresponding capability to writePrimitiveArray in BufferedDataOutputStream to read in an array of Strings.
    
    Parameters:
    
    o - The object to be read. It must be an array of a primitive type, or an array of Object's.
    
    Returns:
    
    number of bytes read.
    
    Throws:
    
    java.io.IOException - if the underlying read operation fails
  - readShort
```
public short readShort()
                throws java.io.IOException
```
    Specified by:
    
    readShort in interface java.io.DataInput
    
    Throws:
    
    java.io.IOException
  - readUnsignedByte
```
public int readUnsignedByte()
                     throws java.io.IOException
```
    Specified by:
    
    readUnsignedByte in interface java.io.DataInput
    
    Throws:
    
    java.io.IOException
  - readUnsignedShort
```
public int readUnsignedShort()
                      throws java.io.IOException
```
    Specified by:
    
    readUnsignedShort in interface java.io.DataInput
    
    Throws:
    
    java.io.IOException
  - readUTF
```
public java.lang.String readUTF()
                         throws java.io.IOException
```
    Specified by:
    
    readUTF in interface java.io.DataInput
    
    Throws:
    
    java.io.IOException
  - skipAllBytes
```
public void skipAllBytes(int toSkip)
                  throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Skip the number of bytes. This differs from the skip method in that it will throw an EOF if a forward skip cannot be fully accomplished... (However that isn't supposed to happen with a random access file, so there is probably no operational difference).
    
    Specified by:
    
    skipAllBytes in interface ArrayDataInput
    
    Parameters:
    
    toSkip - the number of bytes to skip
    
    Throws:
    
    java.io.IOException - if the underlying stream failed
  - skipAllBytes
```
public void skipAllBytes(long toSkip)
                  throws java.io.IOException
```
    Description copied from interface: ArrayDataInput
    
    Skip the number of bytes. This differs from the skip method in that it will throw an EOF if a forward skip cannot be fully accomplished... (However that isn't supposed to happen with a random access file, so there is probably no operational difference).
    
    Specified by:
    
    skipAllBytes in interface ArrayDataInput
    
    Parameters:
    
    toSkip - the number of bytes to skip
    
    Throws:
    
    java.io.IOException - if the underlying stream failed
  - skipBytes
```
public int skipBytes(int toSkip)
              throws java.io.IOException
```
    Specified by:
    
    skipBytes in interface java.io.DataInput
    
    Throws:
    
    java.io.IOException
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object

Class BufferedDataInputStream

Field Summary

Fields inherited from class java.io.BufferedInputStream

Fields inherited from class java.io.FilterInputStream

Fields inherited from interface nom.tam.util.FitsIO

Constructor Summary

Method Summary

Methods inherited from class java.io.BufferedInputStream

Methods inherited from class java.io.FilterInputStream

Methods inherited from class java.lang.Object

Methods inherited from interface nom.tam.util.ArrayDataInput

Methods inherited from interface nom.tam.util.FitsIO

Constructor Detail

BufferedDataInputStream

BufferedDataInputStream

Method Detail

read

read

read

read

read

read

read

read

read

read

read

read

read

read

read

readArray

readBoolean

readByte

readChar

readDouble

readFloat

readFully

readFully

readInt

readLArray

readLine

readLong

readPrimitiveArray

readShort

readUnsignedByte

readUnsignedShort

readUTF

skipAllBytes

skipAllBytes

skipBytes

toString