Module io.netty5.common
Package io.netty5.util.internal

Class PlatformDependent

  • public final class PlatformDependent
extends Object
    Utility that detects various properties specific to the current runtime environment, such as Java version and the availability of the sun.misc.Unsafe object.

    You can disable the use of sun.misc.Unsafe if you specify the system property io.netty5.noUnsafe.

    • Field Detail

      • BIG_ENDIAN_NATIVE_ORDER

        public static final boolean BIG_ENDIAN_NATIVE_ORDER

    • Method Detail

      • byteArrayBaseOffset

        public static long byteArrayBaseOffset()

      • hasDirectBufferNoCleanerConstructor

        public static boolean hasDirectBufferNoCleanerConstructor()

      • allocateUninitializedArray

        public static byte[] allocateUninitializedArray​(int size)

      • isAndroid

        public static boolean isAndroid()
        Returns true if and only if the current platform is Android

      • isWindows

        public static boolean isWindows()
        Return true if the JVM is running on Windows

      • isOsx

        public static boolean isOsx()
        Return true if the JVM is running on OSX / MacOS

      • maybeSuperUser

        public static boolean maybeSuperUser()
        Return true if the current user may be a super-user. Be aware that this is just an hint and so it may return false-positives.

      • javaVersion

        public static int javaVersion()
        Return the version of Java under which this library is used.

      • canEnableTcpNoDelayByDefault

        public static boolean canEnableTcpNoDelayByDefault()
        Returns true if and only if it is fine to enable TCP_NODELAY socket option by default.

      • hasUnsafe

        public static boolean hasUnsafe()
        Return true if sun.misc.Unsafe was found on the classpath and can be used for accelerated direct memory access.

      • getUnsafeUnavailabilityCause

        public static Throwable getUnsafeUnavailabilityCause()
        Return the reason (if any) why sun.misc.Unsafe was not available.

      • isUnaligned

        public static boolean isUnaligned()
        true if and only if the platform supports unaligned access.
        See Also:
        Wikipedia on segfault

      • directBufferPreferred

        public static boolean directBufferPreferred()
        Returns true if the platform has reliable low-level direct buffer access API and a user has not specified -Dio.netty5.noPreferDirect option.

      • maxDirectMemory

        public static long maxDirectMemory()
        Returns the maximum memory reserved for direct buffer allocation.

      • usedDirectMemory

        public static long usedDirectMemory()
        Returns the current memory reserved for direct buffer allocation. This method returns -1 in case that a value is not available.
        See Also:
        maxDirectMemory()

      • tmpdir

        public static File tmpdir()
        Returns the temporary directory.

      • bitMode

        public static int bitMode()
        Returns the bit mode of the current VM (usually 32 or 64.)

      • addressSize

        public static int addressSize()
        Return the address size of the OS. 4 (for 32 bits systems ) and 8 (for 64 bits systems).

      • allocateMemory

        public static long allocateMemory​(long size)

      • freeMemory

        public static void freeMemory​(long address)

      • reallocateMemory

        public static long reallocateMemory​(long address,
                                    long newSize)

      • throwException

        public static void throwException​(Throwable t)
        Raises an exception bypassing compiler checks for checked exceptions.

      • freeDirectBuffer

        public static void freeDirectBuffer​(ByteBuffer buffer)
        Try to deallocate the specified direct ByteBuffer. Please note this method does nothing if the current platform does not support this operation or the specified buffer is not a direct buffer.

      • directBufferAddress

        public static long directBufferAddress​(ByteBuffer buffer)

      • directBuffer

        public static ByteBuffer directBuffer​(long memoryAddress,
                                      int size,
                                      Object attachment)

      • getObject

        public static Object getObject​(Object object,
                               long fieldOffset)

      • getByte

        public static byte getByte​(Object object,
                           long fieldOffset)

      • getShort

        public static short getShort​(Object object,
                             long fieldOffset)

      • getChar

        public static char getChar​(Object object,
                           long fieldOffset)

      • getInt

        public static int getInt​(Object object,
                         long fieldOffset)

      • getFloat

        public static float getFloat​(Object object,
                             long fieldOffset)

      • getLong

        public static long getLong​(Object object,
                           long fieldOffset)

      • getDouble

        public static double getDouble​(Object object,
                               long fieldOffset)

      • getIntVolatile

        public static int getIntVolatile​(long address)

      • putIntOrdered

        public static void putIntOrdered​(long adddress,
                                 int newValue)

      • getByte

        public static byte getByte​(long address)

      • getShort

        public static short getShort​(long address)

      • getInt

        public static int getInt​(long address)

      • getLong

        public static long getLong​(long address)

      • getByte

        public static byte getByte​(byte[] data,
                           int index)

      • getByte

        public static byte getByte​(byte[] data,
                           long index)

      • getShort

        public static short getShort​(byte[] data,
                             int index)

      • getInt

        public static int getInt​(byte[] data,
                         int index)

      • getInt

        public static int getInt​(int[] data,
                         long index)

      • getLong

        public static long getLong​(byte[] data,
                           int index)

      • getLong

        public static long getLong​(long[] data,
                           long index)

      • putByte

        public static void putByte​(long address,
                           byte value)

      • putShort

        public static void putShort​(long address,
                            short value)

      • putInt

        public static void putInt​(long address,
                          int value)

      • putLong

        public static void putLong​(long address,
                           long value)

      • putByte

        public static void putByte​(byte[] data,
                           int index,
                           byte value)

      • putByte

        public static void putByte​(Object data,
                           long offset,
                           byte value)

      • putShort

        public static void putShort​(Object data,
                            long offset,
                            short value)

      • putChar

        public static void putChar​(Object data,
                           long offset,
                           char value)

      • putInt

        public static void putInt​(Object data,
                          long offset,
                          int value)

      • putFloat

        public static void putFloat​(Object data,
                            long offset,
                            float value)

      • putLong

        public static void putLong​(Object data,
                           long offset,
                           long value)

      • putDouble

        public static void putDouble​(Object data,
                             long offset,
                             double value)

      • putShort

        public static void putShort​(byte[] data,
                            int index,
                            short value)

      • putInt

        public static void putInt​(byte[] data,
                          int index,
                          int value)

      • putLong

        public static void putLong​(byte[] data,
                           int index,
                           long value)

      • putObject

        public static void putObject​(Object o,
                             long offset,
                             Object x)

      • objectFieldOffset

        public static long objectFieldOffset​(Field field)

      • copyMemory

        public static void copyMemory​(long srcAddr,
                              long dstAddr,
                              long length)

      • copyMemory

        public static void copyMemory​(byte[] src,
                              int srcIndex,
                              long dstAddr,
                              long length)

      • copyMemory

        public static void copyMemory​(byte[] src,
                              int srcIndex,
                              byte[] dst,
                              int dstIndex,
                              long length)

      • copyMemory

        public static void copyMemory​(Object src,
                              long srcOffset,
                              Object dst,
                              long dstOffset,
                              long length)

      • copyMemory

        public static void copyMemory​(long srcAddr,
                              byte[] dst,
                              int dstIndex,
                              long length)

      • setMemory

        public static void setMemory​(byte[] dst,
                             int dstIndex,
                             long bytes,
                             byte value)

      • setMemory

        public static void setMemory​(Object base,
                             long offset,
                             long length,
                             byte value)

      • setMemory

        public static void setMemory​(long address,
                             long bytes,
                             byte value)

      • hasAlignDirectByteBuffer

        public static boolean hasAlignDirectByteBuffer()

      • alignDirectBuffer

        public static ByteBuffer alignDirectBuffer​(ByteBuffer buffer,
                                           int alignment)

      • align

        public static long align​(long value,
                         int alignment)

      • roundToPowerOfTwo

        public static int roundToPowerOfTwo​(int value)

      • useDirectBufferNoCleaner

        public static boolean useDirectBufferNoCleaner()

      • equals

        public static boolean equals​(byte[] bytes1,
                             int startPos1,
                             byte[] bytes2,
                             int startPos2,
                             int length)
        Compare two byte arrays for equality. For performance reasons no bounds checking on the parameters is performed.
        Parameters:
        bytes1 - the first byte array.
        startPos1 - the position (inclusive) to start comparing in bytes1.
        bytes2 - the second byte array.
        startPos2 - the position (inclusive) to start comparing in bytes2.
        length - the amount of bytes to compare. This is assumed to be validated as not going out of bounds by the caller.

      • isZero

        public static boolean isZero​(byte[] bytes,
                             int startPos,
                             int length)
        Determine if a subsection of an array is zero.
        Parameters:
        bytes - The byte array.
        startPos - The starting index (inclusive) in bytes.
        length - The amount of bytes to check for zero.
        Returns:
        false if bytes[startPos:startsPos+length) contains a value other than zero.

      • equalsConstantTime

        public static int equalsConstantTime​(byte[] bytes1,
                                     int startPos1,
                                     byte[] bytes2,
                                     int startPos2,
                                     int length)
        Compare two byte arrays for equality without leaking timing information. For performance reasons no bounds checking on the parameters is performed.

        The int return type is intentional and is designed to allow cascading of constant time operations: 

             byte[] s1 = new {1, 2, 3};
     byte[] s2 = new {1, 2, 3};
     byte[] s3 = new {1, 2, 3};
     byte[] s4 = new {4, 5, 6};
     boolean equals = (equalsConstantTime(s1, 0, s2, 0, s1.length) &
                       equalsConstantTime(s3, 0, s4, 0, s3.length)) != 0;
        Parameters:
        bytes1 - the first byte array.
        startPos1 - the position (inclusive) to start comparing in bytes1.
        bytes2 - the second byte array.
        startPos2 - the position (inclusive) to start comparing in bytes2.
        length - the amount of bytes to compare. This is assumed to be validated as not going out of bounds by the caller.
        Returns:
        0 if not equal. 1 if equal.

      • hashCodeAscii

        public static int hashCodeAscii​(byte[] bytes,
                                int startPos,
                                int length)
        Calculate a hash code of a byte array assuming ASCII character encoding. The resulting hash code will be case insensitive.
        Parameters:
        bytes - The array which contains the data to hash.
        startPos - What index to start generating a hash code in bytes
        length - The amount of bytes that should be accounted for in the computation.
        Returns:
        The hash code of bytes assuming ASCII character encoding. The resulting hash code will be case insensitive.

      • hashCodeAscii

        public static int hashCodeAscii​(CharSequence bytes)
        Calculate a hash code of a byte array assuming ASCII character encoding. The resulting hash code will be case insensitive.

        This method assumes that bytes is equivalent to a byte[] but just using CharSequence for storage. The upper most byte of each char from bytes is ignored.

        Parameters:
        bytes - The array which contains the data to hash (assumed to be equivalent to a byte[]).
        Returns:
        The hash code of bytes assuming ASCII character encoding. The resulting hash code will be case insensitive.

      • newMpscQueue

        public static <T> Queue<T> newMpscQueue()
        Create a new Queue which is safe to use for multiple producers (different threads) and a single consumer (one thread!).
        Returns:
        A MPSC queue which may be unbounded.

      • newMpscQueue

        public static <T> Queue<T> newMpscQueue​(int maxCapacity)
        Create a new Queue which is safe to use for multiple producers (different threads) and a single consumer (one thread!).

      • newMpscQueue

        public static <T> Queue<T> newMpscQueue​(int chunkSize,
                                        int maxCapacity)
        Create a new Queue which is safe to use for multiple producers (different threads) and a single consumer (one thread!). The queue will grow and shrink its capacity in units of the given chunk size.

      • newSpscQueue

        public static <T> Queue<T> newSpscQueue()
        Create a new Queue which is safe to use for single producer (one thread!) and a single consumer (one thread!).

      • newFixedMpscQueue

        public static <T> Queue<T> newFixedMpscQueue​(int capacity)
        Create a new Queue which is safe to use for multiple producers (different threads) and a single consumer (one thread!) with the given fixes capacity.

      • newConcurrentDeque

        public static <C> Deque<C> newConcurrentDeque()
        Returns a new concurrent Deque.

      • unwrapUnsafeOrNull

        public static Object unwrapUnsafeOrNull()

      • isJ9Jvm

        public static boolean isJ9Jvm()
        Returns true if the running JVM is either IBM J9 or Eclipse OpenJ9, false otherwise.

      • isIkvmDotNet

        public static boolean isIkvmDotNet()
        Returns true if the running JVM is IKVM.NET, false otherwise.

      • estimateMaxDirectMemory

        public static long estimateMaxDirectMemory()
        Compute an estimate of the maximum amount of direct memory available to this JVM.

        The computation is not cached, so you probably want to use maxDirectMemory() instead.

        This will produce debug log output when called.

        Returns:
        The estimated max direct memory, in bytes.

      • normalizedArch

        public static String normalizedArch()

      • normalizedOs

        public static String normalizedOs()

      • normalizedLinuxClassifiers

        public static Set<String> normalizedLinuxClassifiers()