com.yahoo.memory

Class MemoryUtil

java.lang.Object

com.yahoo.memory.MemoryUtil

public final class MemoryUtil
extends Object

Useful utilities that work with Memory.

Author:

Lee Rhodes

Method Summary

Modifier and Type	Method and Description
static int	binarySearchLongs(Memory mem, int fromLongIndex, int toLongIndex, long key) Searches a range of the specified array of longs for the specified value using the binary search algorithm.
static void	copy(Memory source, long srcOffsetBytes, Memory destination, long dstOffsetBytes, long lengthBytes) Deprecated. Use Memory.copy(long, Memory, long, long) instead.
static Memory	memoryRequestHandler(Memory origMem, long newCapacityBytes, boolean copy) Exception handler for requesting a new Memory allocation of the given newCapacityBytes, using the MemoryRequest callback interface.

Methods inherited from class java.lang.Object

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

Method Detail

copy

@Deprecated
public static void copy(Memory source,
                                    long srcOffsetBytes,
                                    Memory destination,
                                    long dstOffsetBytes,
                                    long lengthBytes)

Deprecated. Use Memory.copy(long, Memory, long, long) instead.

General purpose copy function between two Memories.

Parameters:

source - the source Memory

srcOffsetBytes - the source offset

destination - the destination Memory

dstOffsetBytes - the destination offset

lengthBytes - the number of bytes to copy

binarySearchLongs

public static int binarySearchLongs(Memory mem,
                                    int fromLongIndex,
                                    int toLongIndex,
                                    long key)

Searches a range of the specified array of longs for the specified value using the binary search algorithm. The range must be sorted (as by the sort(long[], int, int) method) prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.

Parameters:

mem - the Memory to be searched

fromLongIndex - the index of the first element (inclusive) to be searched

toLongIndex - the index of the last element (exclusive) to be searched

key - the value to be searched for

Returns:

index of the search key, if it is contained in the array within the specified range; otherwise, (-(insertion point) - 1). The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element in the range greater than the key, or toIndex if all elements in the range are less than the specified key. Note that this guarantees that the return value will be ≥ 0 if and only if the key is found.

memoryRequestHandler

public static Memory memoryRequestHandler(Memory origMem,
                                          long newCapacityBytes,
                                          boolean copy)

Exception handler for requesting a new Memory allocation of the given newCapacityBytes, using the MemoryRequest callback interface. If copy is true, the origMem will be copied into the new Memory.

Parameters:

origMem - The original Memory that needs to be replaced by a newly allocated Memory.

newCapacityBytes - The required capacity of the new Memory.

copy - if true, data from the origMem will be copied to the new Memory as space allows and the origMemory will be requested to be freed. If false, no copy will occur and the request to free the origMem will not occur.

Returns:

the newly requested Memory