Buf

All Known Implementing Classes:

BankBuf, SimpleNioBuf, WrapperBuf
```
public interface Buf
```
Represents a sequence of bytes along with operations to read primitive values from it. This interface abstracts away implementation details such as storage mechanism, data encoding and pointer length. It is capable of dealing with 64-bit lengths and offsets. All of the read* methods are safe for use from multiple threads concurrently.

Since:

18 Jun 2013

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`java.io.InputStream`	`createInputStream(long offset)` Returns an input stream consisting of all the bytes in this buf starting from the given offset.
`Buf`	`fillNewBuf(long count, java.io.InputStream in)` Creates a new Buf of a given length populated from a given input stream.
`long`	`getLength()` Returns the extent of this buf in bytes.
`boolean`	`isBigendian()` Determines the data encoding of this buf.
`boolean`	`isBit64()` Determines the 64bit-ness of this buf.
`java.lang.String`	`readAsciiString(Pointer ptr, int nbyte)` Reads a fixed number of bytes interpreting them as ASCII characters and returns the result as a string.
`void`	`readDataBytes(long offset, int count, byte[] array)` Reads a sequence of byte values from this buf into an array.
`void`	`readDataDoubles(long offset, int count, double[] array)` Reads a sequence of double values from this buf into an array.
`void`	`readDataFloats(long offset, int count, float[] array)` Reads a sequence of float values from this buf into an array.
`void`	`readDataInts(long offset, int count, int[] array)` Reads a sequence of int values from this buf into an array.
`void`	`readDataLongs(long offset, int count, long[] array)` Reads a sequence of long integer values from this buf into an array.
`void`	`readDataShorts(long offset, int count, short[] array)` Reads a sequence of short values from this buf into an array.
`int`	`readInt(Pointer ptr)` Reads a signed big-endian 4-byte integer from the pointer position.
`long`	`readOffset(Pointer ptr)` Reads a file offset or size from the pointer position.
`int`	`readUnsignedByte(Pointer ptr)` Reads a single byte from the pointer position, returning a value in the range 0..255.
`void`	`setBit64(boolean isBit64)` Sets the 64bit-ness of this buf.
`void`	`setEncoding(boolean isBigendian)` Sets the encoding for reading numeric values as performed by the `readData*` methods.

- Method Detail
  - getLength
```
long getLength()
```
    Returns the extent of this buf in bytes.
    
    Returns:
    
    buffer length
  - readUnsignedByte
```
int readUnsignedByte(Pointer ptr)
              throws java.io.IOException
```
    Reads a single byte from the pointer position, returning a value in the range 0..255. Pointer position is moved on appropriately.
    
    Parameters:
    
    ptr - pointer
    
    Returns:
    
    byte value
    
    Throws:
    
    java.io.IOException
  - readInt
```
int readInt(Pointer ptr)
     throws java.io.IOException
```
    Reads a signed big-endian 4-byte integer from the pointer position. Pointer position is moved on appropriately.
    
    Parameters:
    
    ptr - pointer
    
    Returns:
    
    integer value
    
    Throws:
    
    java.io.IOException
  - readOffset
```
long readOffset(Pointer ptr)
         throws java.io.IOException
```
    Reads a file offset or size from the pointer position. This is a signed big-endian integer, occupying either 4 or 8 bytes according to the return value of isBit64(). Pointer position is moved on appropriately.
    
    Returns:
    
    buffer size or offset value
    
    Throws:
    
    java.io.IOException
  - readAsciiString
```
java.lang.String readAsciiString(Pointer ptr,
                                 int nbyte)
                          throws java.io.IOException
```
    Reads a fixed number of bytes interpreting them as ASCII characters and returns the result as a string. If a character 0x00 appears before nbyte bytes have been read, it is taken as the end of the string. Pointer position is moved on appropriately.
    
    Parameters:
    
    ptr - pointer
    
    nbyte - maximum number of bytes in string
    
    Returns:
    
    ASCII string
    
    Throws:
    
    java.io.IOException
  - setBit64
```
void setBit64(boolean isBit64)
```
    Sets the 64bit-ness of this buf. This determines whether readOffset reads 4- or 8-byte values.
    This method should be called before the readOffset method is invoked.
    
    Parameters:
    
    isBit64 - true for 8-byte offsets, false for 4-byte offsets
  - isBit64
```
boolean isBit64()
```
    Determines the 64bit-ness of this buf. This determines whether readOffset reads 4- or 8-byte values.
    
    Returns:
    
    true for 8-byte offsets, false for 4-byte offsets
  - setEncoding
```
void setEncoding(boolean isBigendian)
```
    Sets the encoding for reading numeric values as performed by the readData* methods.
    As currently specified, there are only two possibiliies, Big-Endian and Little-Endian. Interface and implementation would need to be reworked somewhat to accommodate the (presumably, rarely seen in this day and age) D_FLOAT and G_FLOAT encodings supported by the CDF standard.
    This method should be called before any of the readData* methods are invoked.
    
    Parameters:
    
    isBigendian - true for big-endian, false for little-endian
  - isBigendian
```
boolean isBigendian()
```
    Determines the data encoding of this buf.
    
    Returns:
    
    true for big-endian, false for little-endian
  - readDataBytes
```
void readDataBytes(long offset,
                   int count,
                   byte[] array)
            throws java.io.IOException
```
    Reads a sequence of byte values from this buf into an array.
    
    Parameters:
    
    offset - position sequence start in this buffer in bytes
    
    count - number of byte values to read
    
    array - array to receive values, starting at array element 0
    
    Throws:
    
    java.io.IOException
  - readDataShorts
```
void readDataShorts(long offset,
                    int count,
                    short[] array)
             throws java.io.IOException
```
    Reads a sequence of short values from this buf into an array.
    
    Parameters:
    
    offset - position sequence start in this buffer in bytes
    
    count - number of short values to read
    
    array - array to receive values, starting at array element 0
    
    Throws:
    
    java.io.IOException
  - readDataInts
```
void readDataInts(long offset,
                  int count,
                  int[] array)
           throws java.io.IOException
```
    Reads a sequence of int values from this buf into an array.
    
    Parameters:
    
    offset - position sequence start in this buffer in bytes
    
    count - number of int values to read
    
    array - array to receive values, starting at array element 0
    
    Throws:
    
    java.io.IOException
  - readDataLongs
```
void readDataLongs(long offset,
                   int count,
                   long[] array)
            throws java.io.IOException
```
    Reads a sequence of long integer values from this buf into an array.
    
    Parameters:
    
    offset - position sequence start in this buffer in bytes
    
    count - number of long values to read
    
    array - array to receive values, starting at array element 0
    
    Throws:
    
    java.io.IOException
  - readDataFloats
```
void readDataFloats(long offset,
                    int count,
                    float[] array)
             throws java.io.IOException
```
    Reads a sequence of float values from this buf into an array.
    
    Parameters:
    
    offset - position sequence start in this buffer in bytes
    
    count - number of float values to read
    
    array - array to receive values, starting at array element 0
    
    Throws:
    
    java.io.IOException
  - readDataDoubles
```
void readDataDoubles(long offset,
                     int count,
                     double[] array)
              throws java.io.IOException
```
    Reads a sequence of double values from this buf into an array.
    
    Parameters:
    
    offset - position sequence start in this buffer in bytes
    
    count - number of double values to read
    
    array - array to receive values, starting at array element 0
    
    Throws:
    
    java.io.IOException
  - createInputStream
```
java.io.InputStream createInputStream(long offset)
```
    Returns an input stream consisting of all the bytes in this buf starting from the given offset.
    
    Parameters:
    
    offset - position of first byte in buf that will appear in the returned stream
    
    Returns:
    
    input stream
  - fillNewBuf
```
Buf fillNewBuf(long count,
               java.io.InputStream in)
        throws java.io.IOException
```
    Creates a new Buf of a given length populated from a given input stream. The new buf object must have the same data encoding and 64bit-ness as this one.
    
    Parameters:
    
    count - size of new buffer in bytes
    
    in - input stream capable of supplying (at least) count bytes
    
    Returns:
    
    new buffer of length count filled with bytes from in
    
    Throws:
    
    java.io.IOException

Interface Buf

Method Summary

Method Detail

getLength

readUnsignedByte

readInt

readOffset

readAsciiString

setBit64

isBit64

setEncoding

isBigendian

readDataBytes

readDataShorts

readDataInts

readDataLongs

readDataFloats

readDataDoubles

createInputStream

fillNewBuf