Package org.apache.datasketches.memory

Interface WritableMemory

  • All Superinterfaces:
    BaseState, Memory
    public interface WritableMemory
extends Memory
    Defines the writable API for offset access to a resource.
    Author:
    Lee Rhodes

    • Method Detail

      • writableWrap

        static WritableMemory writableWrap​(ByteBuffer byteBuffer)
        Accesses the given ByteBuffer for write operations. The returned WritableMemory object has the same byte order, as the given ByteBuffer.
        Parameters:
        byteBuffer - the given ByteBuffer. It must be non-null, with capacity ≥ 0, and writable.
        Returns:
        a new WritableMemory for write operations on the given ByteBuffer.

      • writableWrap

        static WritableMemory writableWrap​(ByteBuffer byteBuffer,
                                   ByteOrder byteOrder)
        Accesses the given ByteBuffer for write operations. The returned WritableMemory object has the given byte order, ignoring the byte order of the given ByteBuffer for future writes and following reads. However, this does not change the byte order of data already in the ByteBuffer.
        Parameters:
        byteBuffer - the given ByteBuffer. It must be non-null, with capacity ≥ 0, and writable.
        byteOrder - the byte order to be used. It must be non-null.
        Returns:
        a new WritableMemory for write operations on the given ByteBuffer.

      • writableWrap

        static WritableMemory writableWrap​(ByteBuffer byteBuffer,
                                   ByteOrder byteOrder,
                                   MemoryRequestServer memReqSvr)
        Accesses the given ByteBuffer for write operations. The returned WritableMemory object has the given byte order, ignoring the byte order of the given ByteBuffer for future reads and writes. However, this does not change the byte order of data already in the ByteBuffer.
        Parameters:
        byteBuffer - the given ByteBuffer. It must be non-null, with capacity ≥ 0, and writable.
        byteOrder - the byte order to be used. It must be non-null.
        memReqSvr - A user-specified MemoryRequestServer, which may be null. This is a callback mechanism for a user client to request a larger WritableMemory.
        Returns:
        a new WritableMemory for write operations on the given ByteBuffer.

      • writableMap

        static WritableMapHandle writableMap​(File file)
        Maps the entire given file into native-ordered WritableMemory for write operations Calling this method is equivalent to calling writableMap(file, 0, file.length(), ByteOrder.nativeOrder()).
        Parameters:
        file - the given file to map. It must be non-null, with length ≥ 0, and writable.
        Returns:
        WritableMapHandle for managing the mapped Memory. Please read Javadocs for Handle.

      • writableMap

        static WritableMapHandle writableMap​(File file,
                                     long fileOffsetBytes,
                                     long capacityBytes,
                                     ByteOrder byteOrder)
        Maps the specified portion of the given file into Memory for write operations.

        Note: Always qualify this method with the class name, e.g., WritableMemory.map(...).

        Parameters:
        file - the given file to map. It must be non-null, writable and length ≥ 0.
        fileOffsetBytes - the position in the given file in bytes. It must not be negative.
        capacityBytes - the size of the mapped Memory. It must not be negative.
        byteOrder - the byte order to be used for the given file. It must be non-null.
        Returns:
        WritableMapHandle for managing the mapped Memory. Please read Javadocs for Handle.

      • allocateDirect

        static WritableHandle allocateDirect​(long capacityBytes)
        Allocates and provides access to capacityBytes directly in native (off-heap) memory. Native byte order is assumed. The allocated memory will be 8-byte aligned, but may not be page aligned.

        NOTE: Native/Direct memory acquired may have garbage in it. It is the responsibility of the using application to clear this memory, if required, and to call close() when done.

        Parameters:
        capacityBytes - the size of the desired memory in bytes. It must be ≥ 0.
        Returns:
        WritableHandle for this off-heap resource. Please read Javadocs for Handle.

      • allocateDirect

        static WritableHandle allocateDirect​(long capacityBytes,
                                     ByteOrder byteOrder,
                                     MemoryRequestServer memReqSvr)
        Allocates and provides access to capacityBytes directly in native (off-heap) memory. The allocated memory will be 8-byte aligned, but may not be page aligned.

        NOTE: Native/Direct memory acquired may have garbage in it. It is the responsibility of the using application to clear this memory, if required, and to call close() when done.

        Parameters:
        capacityBytes - the size of the desired memory in bytes. It must be ≥ 0.
        byteOrder - the given byte order. It must be non-null.
        memReqSvr - A user-specified MemoryRequestServer, which may be null. This is a callback mechanism for a user client of direct memory to request more memory.
        Returns:
        WritableHandle for this off-heap resource. Please read Javadocs for Handle.

      • writableRegion

        default WritableMemory writableRegion​(long offsetBytes,
                                      long capacityBytes)
        A writable region is a writable view of this object. This returns a new WritableMemory representing the defined writable region with the given offsetBytes and capacityBytes.
        • Returned object's origin = this objects' origin + offsetBytes
        • Returned object's capacity = capacityBytes
        Parameters:
        offsetBytes - the starting offset with respect to this object. It must be ≥ 0.
        capacityBytes - the capacity of the returned object in bytes. It must be ≥ 0.
        Returns:
        a new WritableMemory representing the defined writable region.

      • writableRegion

        WritableMemory writableRegion​(long offsetBytes,
                              long capacityBytes,
                              ByteOrder byteOrder)
        A writable region is a writable view of this object. This returns a new WritableMemory representing the defined writable region with the given offsetBytes, capacityBytes and byte order.
        • Returned object's origin = this objects' origin + offsetBytes
        • Returned object's capacity = capacityBytes
        • Returned object's byte order = byteOrder
        Parameters:
        offsetBytes - the starting offset with respect to this object. It must be ≥ 0.
        capacityBytes - the capacity of the returned object in bytes. It must be ≥ 0.
        byteOrder - the given byte order. It must be non-null.
        Returns:
        a new WritableMemory representing the defined writable region.

      • asWritableBuffer

        default WritableBuffer asWritableBuffer()
        Returns a new WritableBuffer with a writable view of this object.
        • Returned object's origin = this object's origin
        • Returned object's start = 0
        • Returned object's position = 0
        • Returned object's end = this object's capacity
        • Returned object's capacity = this object's capacity
        • Returned object's start, position and end are mutable
        Returns:
        a new WritableBuffer with a view of this WritableMemory

      • asWritableBuffer

        WritableBuffer asWritableBuffer​(ByteOrder byteOrder)
        Returns a new WritableBuffer with a writable view of this object with the given byte order.
        • Returned object's origin = this object's origin
        • Returned object's start = 0
        • Returned object's position = 0
        • Returned object's end = this object's capacity
        • Returned object's capacity = this object's capacity
        • Returned object's start, position and end are mutable
        Parameters:
        byteOrder - the given byte order
        Returns:
        a new WritableBuffer with a view of this WritableMemory

      • allocate

        static WritableMemory allocate​(int capacityBytes)
        Creates on-heap WritableMemory with the given capacity and the native byte order.
        Parameters:
        capacityBytes - the given capacity in bytes. It must be ≥ 0.
        Returns:
        a new WritableMemory for write operations on a new byte array.

      • allocate

        static WritableMemory allocate​(int capacityBytes,
                               ByteOrder byteOrder)
        Creates on-heap WritableMemory with the given capacity and the given byte order.
        Parameters:
        capacityBytes - the given capacity in bytes. It must be ≥ 0.
        byteOrder - the given byte order to allocate new Memory object with. It must be non-null.
        Returns:
        a new WritableMemory for write operations on a new byte array.

      • allocate

        static WritableMemory allocate​(int capacityBytes,
                               ByteOrder byteOrder,
                               MemoryRequestServer memReqSvr)
        Creates on-heap WritableMemory with the given capacity and the given byte order.
        Parameters:
        capacityBytes - the given capacity in bytes. It must be ≥ 0.
        byteOrder - the given byte order to allocate new Memory object with. It must be non-null.
        memReqSvr - A user-specified MemoryRequestServer, which may be null. This is a callback mechanism for a user client to request a larger WritableMemory.
        Returns:
        a new WritableMemory for write operations on a new byte array.

      • writableWrap

        static WritableMemory writableWrap​(byte[] array)
        Wraps the given primitive array for write operations assuming native byte order.

        Note: Always qualify this method with the class name, e.g., WritableMemory.wrap(...).

        Parameters:
        array - the given primitive array. It must be non-null.
        Returns:
        a new WritableMemory for write operations on the given primitive array.

      • writableWrap

        static WritableMemory writableWrap​(byte[] array,
                                   ByteOrder byteOrder)
        Wraps the given primitive array for write operations with the given byte order.

        Note: Always qualify this method with the class name, e.g., WritableMemory.wrap(...).

        Parameters:
        array - the given primitive array. It must be non-null.
        byteOrder - the byte order to be used. It must be non-null.
        Returns:
        a new WritableMemory for write operations on the given primitive array.

      • writableWrap

        static WritableMemory writableWrap​(byte[] array,
                                   int offsetBytes,
                                   int lengthBytes,
                                   ByteOrder byteOrder)
        Wraps the given primitive array for write operations with the given byte order.

        Note: Always qualify this method with the class name, e.g., WritableMemory.wrap(...).

        Parameters:
        array - the given primitive array. It must be non-null.
        offsetBytes - the byte offset into the given array. It must be ≥ 0.
        lengthBytes - the number of bytes to include from the given array. It must be ≥ 0.
        byteOrder - the byte order to be used. It must be non-null.
        Returns:
        a new WritableMemory for write operations on the given primitive array.

      • writableWrap

        static WritableMemory writableWrap​(byte[] array,
                                   int offsetBytes,
                                   int lengthBytes,
                                   ByteOrder byteOrder,
                                   MemoryRequestServer memReqSvr)
        Wraps the given primitive array for write operations with the given byte order. If the given lengthBytes is zero, backing storage, byte order and read-only status of the returned WritableMemory object are unspecified.

        Note: Always qualify this method with the class name, e.g., WritableMemory.wrap(...).

        Parameters:
        array - the given primitive array. It must be non-null.
        offsetBytes - the byte offset into the given array. It must be ≥ 0.
        lengthBytes - the number of bytes to include from the given array. It must be ≥ 0.
        byteOrder - the byte order to be used. It must be non-null.
        memReqSvr - A user-specified MemoryRequestServer, which may be null. This is a callback mechanism for a user client to request a larger WritableMemory.
        Returns:
        a new WritableMemory for write operations on the given primitive array.

      • writableWrap

        static WritableMemory writableWrap​(boolean[] array)
        Wraps the given primitive array for write operations assuming native byte order.
        Parameters:
        array - the given primitive array. It must be non-null.
        Returns:
        a new WritableMemory for write operations on the given primitive array.

      • writableWrap

        static WritableMemory writableWrap​(char[] array)
        Wraps the given primitive array for write operations assuming native byte order.
        Parameters:
        array - the given primitive array.
        Returns:
        a new WritableMemory for write operations on the given primitive array.

      • writableWrap

        static WritableMemory writableWrap​(short[] array)
        Wraps the given primitive array for write operations assuming native byte order.
        Parameters:
        array - the given primitive array.
        Returns:
        a new WritableMemory for write operations on the given primitive array.

      • writableWrap

        static WritableMemory writableWrap​(int[] array)
        Wraps the given primitive array for write operations assuming native byte order.
        Parameters:
        array - the given primitive array.
        Returns:
        a new WritableMemory for write operations on the given primitive array.

      • writableWrap

        static WritableMemory writableWrap​(long[] array)
        Wraps the given primitive array for write operations assuming native byte order.
        Parameters:
        array - the given primitive array.
        Returns:
        a new WritableMemory for write operations on the given primitive array.

      • writableWrap

        static WritableMemory writableWrap​(float[] array)
        Wraps the given primitive array for write operations assuming native byte order.
        Parameters:
        array - the given primitive array.
        Returns:
        a new WritableMemory for write operations on the given primitive array.

      • writableWrap

        static WritableMemory writableWrap​(double[] array)
        Wraps the given primitive array for write operations assuming native byte order.
        Parameters:
        array - the given primitive array.
        Returns:
        a new WritableMemory for write operations on the given primitive array.

      • putBoolean

        void putBoolean​(long offsetBytes,
                boolean value)
        Puts the boolean value at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        value - the value to put

      • putBooleanArray

        void putBooleanArray​(long offsetBytes,
                     boolean[] srcArray,
                     int srcOffsetBooleans,
                     int lengthBooleans)
        Puts the boolean array at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        srcArray - The source array.
        srcOffsetBooleans - offset in array units
        lengthBooleans - number of array units to transfer

      • putByte

        void putByte​(long offsetBytes,
             byte value)
        Puts the byte value at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        value - the value to put

      • putByteArray

        void putByteArray​(long offsetBytes,
                  byte[] srcArray,
                  int srcOffsetBytes,
                  int lengthBytes)
        Puts the byte array at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        srcArray - The source array.
        srcOffsetBytes - offset in array units
        lengthBytes - number of array units to transfer

      • putChar

        void putChar​(long offsetBytes,
             char value)
        Puts the char value at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        value - the value to put

      • putCharArray

        void putCharArray​(long offsetBytes,
                  char[] srcArray,
                  int srcOffsetChars,
                  int lengthChars)
        Puts the char array at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        srcArray - The source array.
        srcOffsetChars - offset in array units
        lengthChars - number of array units to transfer

      • putCharsToUtf8

        long putCharsToUtf8​(long offsetBytes,
                    CharSequence src)
        Encodes characters from the given CharSequence into UTF-8 bytes and puts them into this WritableMemory begining at the given offsetBytes. This is specifically designed to reduce the production of intermediate objects (garbage), thus significantly reducing pressure on the JVM Garbage Collector.
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        src - The source CharSequence to be encoded and put into this WritableMemory. It is the responsibility of the caller to provide sufficient capacity in this WritableMemory for the encoded Utf8 bytes. Characters outside the ASCII range can require 2, 3 or 4 bytes per character to encode.
        Returns:
        the number of bytes encoded

      • putDouble

        void putDouble​(long offsetBytes,
               double value)
        Puts the double value at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        value - the value to put

      • putDoubleArray

        void putDoubleArray​(long offsetBytes,
                    double[] srcArray,
                    int srcOffsetDoubles,
                    int lengthDoubles)
        Puts the double array at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        srcArray - The source array.
        srcOffsetDoubles - offset in array units
        lengthDoubles - number of array units to transfer

      • putFloat

        void putFloat​(long offsetBytes,
              float value)
        Puts the float value at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        value - the value to put

      • putFloatArray

        void putFloatArray​(long offsetBytes,
                   float[] srcArray,
                   int srcOffsetFloats,
                   int lengthFloats)
        Puts the float array at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        srcArray - The source array.
        srcOffsetFloats - offset in array units
        lengthFloats - number of array units to transfer

      • putInt

        void putInt​(long offsetBytes,
            int value)
        Puts the int value at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        value - the value to put

      • putIntArray

        void putIntArray​(long offsetBytes,
                 int[] srcArray,
                 int srcOffsetInts,
                 int lengthInts)
        Puts the int array at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        srcArray - The source array.
        srcOffsetInts - offset in array units
        lengthInts - number of array units to transfer

      • putLong

        void putLong​(long offsetBytes,
             long value)
        Puts the long value at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        value - the value to put

      • putLongArray

        void putLongArray​(long offsetBytes,
                  long[] srcArray,
                  int srcOffsetLongs,
                  int lengthLongs)
        Puts the long array at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        srcArray - The source array.
        srcOffsetLongs - offset in array units
        lengthLongs - number of array units to transfer

      • putShort

        void putShort​(long offsetBytes,
              short value)
        Puts the short value at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        value - the value to put

      • putShortArray

        void putShortArray​(long offsetBytes,
                   short[] srcArray,
                   int srcOffsetShorts,
                   int lengthShorts)
        Puts the short array at the given offset
        Parameters:
        offsetBytes - offset bytes relative to this WritableMemory start
        srcArray - The source array.
        srcOffsetShorts - offset in array units
        lengthShorts - number of array units to transfer

      • getAndAddLong

        long getAndAddLong​(long offsetBytes,
                   long delta)
        Atomically adds the given value to the long located at offsetBytes.
        Parameters:
        offsetBytes - offset bytes relative to this Memory start
        delta - the amount to add
        Returns:
        the the previous value

      • compareAndSwapLong

        boolean compareAndSwapLong​(long offsetBytes,
                           long expect,
                           long update)
        Atomically sets the current value at the memory location to the given updated value if and only if the current value == the expected value.
        Parameters:
        offsetBytes - offset bytes relative to this Memory start
        expect - the expected value
        update - the new value
        Returns:
        true if successful. False return indicates that the current value at the memory location was not equal to the expected value.

      • getAndSetLong

        long getAndSetLong​(long offsetBytes,
                   long newValue)
        Atomically exchanges the given value with the current value located at offsetBytes.
        Parameters:
        offsetBytes - offset bytes relative to this Memory start
        newValue - new value
        Returns:
        the previous value

      • getArray

        Object getArray()
        Returns the primitive backing array, otherwise null.
        Returns:
        the primitive backing array, otherwise null.

      • clear

        void clear()
        Clears all bytes of this Memory to zero

      • clear

        void clear​(long offsetBytes,
           long lengthBytes)
        Clears a portion of this Memory to zero.
        Parameters:
        offsetBytes - offset bytes relative to this Memory start
        lengthBytes - the length in bytes

      • clearBits

        void clearBits​(long offsetBytes,
               byte bitMask)
        Clears the bits defined by the bitMask
        Parameters:
        offsetBytes - offset bytes relative to this Memory start.
        bitMask - the bits set to one will be cleared

      • fill

        void fill​(byte value)
        Fills all bytes of this Memory region to the given byte value.
        Parameters:
        value - the given byte value

      • fill

        void fill​(long offsetBytes,
          long lengthBytes,
          byte value)
        Fills a portion of this Memory region to the given byte value.
        Parameters:
        offsetBytes - offset bytes relative to this Memory start
        lengthBytes - the length in bytes
        value - the given byte value

      • setBits

        void setBits​(long offsetBytes,
             byte bitMask)
        Sets the bits defined by the bitMask
        Parameters:
        offsetBytes - offset bytes relative to this Memory start
        bitMask - the bits set to one will be set

      • getMemoryRequestServer

        MemoryRequestServer getMemoryRequestServer()
        WritableMemory enables this for ByteBuffer, Heap and Direct Memory backed resources. Map backed resources will always return null. Gets the MemoryRequestServer object, if set, for the above resources to request additional memory. The user must customize the actions of the MemoryRequestServer by implementing the MemoryRequestServer interface and set using one of these methods: Simple implementation examples include the DefaultMemoryRequestServer in the main tree, as well as the ExampleMemoryRequestServerTest and the use with ByteBuffer documented in the DruidIssue11544Test in the test tree.
        Returns:
        the MemoryRequestServer object or null.