Examples of MemorySegment

eu.stratosphere.core.memory.MemorySegment
This class represents a piece of memory allocated from the memory manager. The segment is backed by a byte array and features random put and get methods for the basic types that are stored in a byte-wise fashion in the memory.
Comments on the implementation: We make heavy use of operations that are supported by native instructions, to achieve a high efficiency. Multi byte types (int, long, float, double, ...) are read and written with "unsafe" native commands. Little-endian to big-endian conversion and vice versa are done using the static reverseBytes methods in the boxing data types (for example {@link Integer#reverseBytes(int)}). On x86/amd64, these are translated by the jit compiler to bswap intrinsic commands. Below is an example of the code generated for the {@link MemorySegment#putLongBigEndian(int,long)}function by the just-in-time compiler. The code is grabbed from an oracle jvm 7 using the hotspot disassembler library (hsdis32.dll) and the jvm command -XX:+UnlockDiagnosticVMOptions -XX:CompileCommand=print,*UnsafeMemorySegment.putLongBigEndian. Note that this code realizes both the byte order swapping and the reinterpret cast access to get a long from the byte array.
```
 [Verified Entry Point] 0x00007fc403e19920: sub    $0x18,%rsp 0x00007fc403e19927: mov    %rbp,0x10(%rsp)    ;*synchronization entry ; - eu.stratosphere.nephele.services.memorymanager.UnsafeMemorySegment::putLongBigEndian@-1 (line 652) 0x00007fc403e1992c: mov    0xc(%rsi),%r10d    ;*getfield memory ; - eu.stratosphere.nephele.services.memorymanager.UnsafeMemorySegment::putLong@4 (line 611) ; - eu.stratosphere.nephele.services.memorymanager.UnsafeMemorySegment::putLongBigEndian@12 (line 653) 0x00007fc403e19930: bswap  %rcx 0x00007fc403e19933: shl    $0x3,%r10 0x00007fc403e19937: movslq %edx,%r11 0x00007fc403e1993a: mov    %rcx,0x10(%r10,%r11,1)  ;*invokevirtual putLong ; - eu.stratosphere.nephele.services.memorymanager.UnsafeMemorySegment::putLong@14 (line 611) ; - eu.stratosphere.nephele.services.memorymanager.UnsafeMemorySegment::putLongBigEndian@12 (line 653) 0x00007fc403e1993f: add    $0x10,%rsp 0x00007fc403e19943: pop    %rbp 0x00007fc403e19944: test   %eax,0x5ba76b6(%rip)        # 0x00007fc4099c1000 ;   {poll_return} 0x00007fc403e1994a: retq  
```
org.apache.flink.core.memory.MemorySegment
This class represents a piece of memory allocated from the memory manager. The segment is backed by a byte array and features random put and get methods for the basic types that are stored in a byte-wise fashion in the memory.
Comments on the implementation: We make heavy use of operations that are supported by native instructions, to achieve a high efficiency. Multi byte types (int, long, float, double, ...) are read and written with "unsafe" native commands. Little-endian to big-endian conversion and vice versa are done using the static reverseBytes methods in the boxing data types (for example {@link Integer#reverseBytes(int)}). On x86/amd64, these are translated by the jit compiler to bswap intrinsic commands. Below is an example of the code generated for the {@link MemorySegment#putLongBigEndian(int,long)}function by the just-in-time compiler. The code is grabbed from an oracle jvm 7 using the hotspot disassembler library (hsdis32.dll) and the jvm command -XX:+UnlockDiagnosticVMOptions -XX:CompileCommand=print,*UnsafeMemorySegment.putLongBigEndian. Note that this code realizes both the byte order swapping and the reinterpret cast access to get a long from the byte array.
```
 [Verified Entry Point] 0x00007fc403e19920: sub    $0x18,%rsp 0x00007fc403e19927: mov    %rbp,0x10(%rsp)    ;*synchronization entry ; - org.apache.flink.runtime.memory.UnsafeMemorySegment::putLongBigEndian@-1 (line 652) 0x00007fc403e1992c: mov    0xc(%rsi),%r10d    ;*getfield memory ; - org.apache.flink.runtime.memory.UnsafeMemorySegment::putLong@4 (line 611) ; - org.apache.flink.runtime.memory.UnsafeMemorySegment::putLongBigEndian@12 (line 653) 0x00007fc403e19930: bswap  %rcx 0x00007fc403e19933: shl    $0x3,%r10 0x00007fc403e19937: movslq %edx,%r11 0x00007fc403e1993a: mov    %rcx,0x10(%r10,%r11,1)  ;*invokevirtual putLong ; - org.apache.flink.runtime.memory.UnsafeMemorySegment::putLong@14 (line 611) ; - org.apache.flink.runtime.memory.UnsafeMemorySegment::putLongBigEndian@12 (line 653) 0x00007fc403e1993f: add    $0x10,%rsp 0x00007fc403e19943: pop    %rbp 0x00007fc403e19944: test   %eax,0x5ba76b6(%rip)        # 0x00007fc4099c1000 ;   {poll_return} 0x00007fc403e1994a: retq  
```

Examples of org.apache.flink.core.memory.MemorySegment

    } else {
      this.numSegments = memory.size();
      // load the segments into the queue
      final LinkedBlockingQueue<MemorySegment> queue = writer.getReturnQueue();
      for (int i = memory.size() - 1; i >= 0; --i) {
        final MemorySegment seg = memory.get(i);
        if (seg.size() != segmentSize) {
          throw new IllegalArgumentException("The supplied memory segments are not of the specified size.");
        }
        queue.add(seg);
      }
    }

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Examples of org.apache.flink.core.memory.MemorySegment

    @Override
    protected MemorySegment nextSegment(MemorySegment current, int bytesUsed) throws IOException
    {
      finalizeSegment(current, bytesUsed);
      
      final MemorySegment next;
      if (this.writer == null) {
        this.targetList.add(current);
        next = this.memSource.nextSegment();
      } else {
        this.writer.writeBlock(current);

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