Package nonapi.io.github.classgraph.fileslice.reader

Class RandomAccessFileChannelReader

java.lang.Object

nonapi.io.github.classgraph.fileslice.reader.RandomAccessFileChannelReader

All Implemented Interfaces:

RandomAccessReader

public class RandomAccessFileChannelReader
extends java.lang.Object
implements RandomAccessReader

RandomAccessReader for a File. Reads in little endian order, as required by the zipfile format.

Field Summary

Fields

Modifier and Type	Field	Description
private java.nio.channels.FileChannel	fileChannel	The file channel.
private java.nio.ByteBuffer	reusableByteBuffer	The reusable byte buffer.
private byte[]	scratchArr	The scratch arr.
private java.nio.ByteBuffer	scratchByteBuf	The scratch byte buf.
private long	sliceLength	The slice length.
private long	sliceStartPos	The slice start pos.
private byte[]	utf8Bytes	The utf 8 bytes.

Constructor Summary

Constructors

Constructor	Description
RandomAccessFileChannelReader(java.nio.channels.FileChannel fileChannel, long sliceStartPos, long sliceLength)	Constructor.

Method Summary

Modifier and Type	Method	Description
int	read(long srcOffset, byte[] dstArr, int dstArrStart, int numBytes)	Read bytes into a byte array.
int	read(long srcOffset, java.nio.ByteBuffer dstBuf, int dstBufStart, int numBytes)	Read bytes into a ByteBuffer.
byte	readByte(long offset)	Read a byte at a specific offset (without changing the current cursor offset).
int	readInt(long offset)	Read a int at a specific offset (without changing the current cursor offset).
long	readLong(long offset)	Read a long at a specific offset (without changing the current cursor offset).
short	readShort(long offset)	Read a short at a specific offset (without changing the current cursor offset).
java.lang.String	readString(long offset, int numBytes)	Reads the "modified UTF8" format defined in the Java classfile spec.
java.lang.String	readString(long offset, int numBytes, boolean replaceSlashWithDot, boolean stripLSemicolon)	Reads the "modified UTF8" format defined in the Java classfile spec, optionally replacing '/' with '.', and optionally removing the prefix "L" and the suffix ";".
int	readUnsignedByte(long offset)	Read an unsigned byte at a specific offset (without changing the current cursor offset).
long	readUnsignedInt(long offset)	Read a unsigned int at a specific offset (without changing the current cursor offset).
int	readUnsignedShort(long offset)	Read a unsigned short at a specific offset (without changing the current cursor offset).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

fileChannel

private final java.nio.channels.FileChannel fileChannel

The file channel.

sliceStartPos

private final long sliceStartPos

The slice start pos.

sliceLength

private final long sliceLength

The slice length.

reusableByteBuffer

private java.nio.ByteBuffer reusableByteBuffer

The reusable byte buffer.

scratchArr

private final byte[] scratchArr

The scratch arr.

scratchByteBuf

private final java.nio.ByteBuffer scratchByteBuf

The scratch byte buf.

utf8Bytes

private byte[] utf8Bytes

The utf 8 bytes.

Constructor Detail

RandomAccessFileChannelReader

public RandomAccessFileChannelReader(java.nio.channels.FileChannel fileChannel,
                                     long sliceStartPos,
                                     long sliceLength)

Constructor.

Parameters:

fileChannel - the file channel

sliceStartPos - the slice start pos

sliceLength - the slice length

Method Detail

read

public int read(long srcOffset,
                java.nio.ByteBuffer dstBuf,
                int dstBufStart,
                int numBytes)
         throws java.io.IOException

Description copied from interface: RandomAccessReader

Read bytes into a ByteBuffer.

Specified by:

read in interface RandomAccessReader

Parameters:

srcOffset - The offset to start reading from.

dstBuf - The ByteBuffer to write into.

dstBufStart - The offset within the destination buffer to start writing at.

numBytes - The number of bytes to read.

Returns:

The number of bytes actually read, or -1 if no more bytes could be read.

Throws:

java.io.IOException - If there was an exception while reading.

read

public int read(long srcOffset,
                byte[] dstArr,
                int dstArrStart,
                int numBytes)
         throws java.io.IOException

Description copied from interface: RandomAccessReader

Read bytes into a byte array.

Specified by:

read in interface RandomAccessReader

Parameters:

srcOffset - The offset to start reading from.

dstArr - The byte array to write into.

dstArrStart - The offset within the destination array to start writing at.

numBytes - The number of bytes to read.

Returns:

The number of bytes actually read, or -1 if no more bytes could be read.

Throws:

java.io.IOException - If there was an exception while reading.

readByte

public byte readByte(long offset)
              throws java.io.IOException

Description copied from interface: RandomAccessReader

Read a byte at a specific offset (without changing the current cursor offset).

Specified by:

readByte in interface RandomAccessReader

Parameters:

offset - The buffer offset to read from.

Returns:

The byte at the offset.

Throws:

java.io.IOException - If there was an exception while reading.

readUnsignedByte

public int readUnsignedByte(long offset)
                     throws java.io.IOException

Description copied from interface: RandomAccessReader

Read an unsigned byte at a specific offset (without changing the current cursor offset).

Specified by:

readUnsignedByte in interface RandomAccessReader

Parameters:

offset - The buffer offset to read from.

Returns:

The unsigned byte at the offset.

Throws:

java.io.IOException - If there was an exception while reading.

readShort

public short readShort(long offset)
                throws java.io.IOException

Description copied from interface: RandomAccessReader

Read a short at a specific offset (without changing the current cursor offset).

Specified by:

readShort in interface RandomAccessReader

Parameters:

offset - The buffer offset to read from.

Returns:

The short at the offset.

Throws:

java.io.IOException - If there was an exception while reading.

readUnsignedShort

public int readUnsignedShort(long offset)
                      throws java.io.IOException

Description copied from interface: RandomAccessReader

Read a unsigned short at a specific offset (without changing the current cursor offset).

Specified by:

readUnsignedShort in interface RandomAccessReader

Parameters:

offset - The buffer offset to read from.

Returns:

The unsigned short at the offset.

Throws:

java.io.IOException - If there was an exception while reading.

readInt

public int readInt(long offset)
            throws java.io.IOException

Description copied from interface: RandomAccessReader

Read a int at a specific offset (without changing the current cursor offset).

Specified by:

readInt in interface RandomAccessReader

Parameters:

offset - The buffer offset to read from.

Returns:

The int at the offset.

Throws:

java.io.IOException - If there was an exception while reading.

readUnsignedInt

public long readUnsignedInt(long offset)
                     throws java.io.IOException

Description copied from interface: RandomAccessReader

Read a unsigned int at a specific offset (without changing the current cursor offset).

Specified by:

readUnsignedInt in interface RandomAccessReader

Parameters:

offset - The buffer offset to read from.

Returns:

The int at the offset, as a long.

Throws:

java.io.IOException - If there was an exception while reading.

readLong

public long readLong(long offset)
              throws java.io.IOException

Description copied from interface: RandomAccessReader

Read a long at a specific offset (without changing the current cursor offset).

Specified by:

readLong in interface RandomAccessReader

Parameters:

offset - The buffer offset to read from.

Returns:

The long at the offset.

Throws:

java.io.IOException - If there was an exception while reading.

readString

public java.lang.String readString(long offset,
                                   int numBytes,
                                   boolean replaceSlashWithDot,
                                   boolean stripLSemicolon)
                            throws java.io.IOException

Description copied from interface: RandomAccessReader

Reads the "modified UTF8" format defined in the Java classfile spec, optionally replacing '/' with '.', and optionally removing the prefix "L" and the suffix ";".

Specified by:

readString in interface RandomAccessReader

Parameters:

offset - The start offset of the string.

numBytes - The number of bytes of the UTF8 encoding of the string.

replaceSlashWithDot - If true, replace '/' with '.'.

stripLSemicolon - If true, string final ';' character.

Returns:

The string.

Throws:

java.io.IOException - If an I/O exception occurs.

readString

public java.lang.String readString(long offset,
                                   int numBytes)
                            throws java.io.IOException

Description copied from interface: RandomAccessReader

Reads the "modified UTF8" format defined in the Java classfile spec.

Specified by:

readString in interface RandomAccessReader

Parameters:

offset - The start offset of the string.

numBytes - The number of bytes of the UTF8 encoding of the string.

Returns:

The string.

Throws:

java.io.IOException - If an I/O exception occurs.