Pop data from the Stack.

@return topmost element of the stack, or null if stack is empty.
198101
public E pop() {
        StackNode<E> oldTop, newTop;

        while (true) {
            oldTop = top.get();
            if (oldTop == null)
                return null;
            newTop = oldTop.next;
            if (top.compareAndSet(oldTop, newTop))
                break;
        }

        return oldTop.data;
    }
778091
public E removeLast () {
		if (size > 0) {
			E e = data[--size];
			data[size] = null;
			return e;
		}

		return null;
	}
1121837
@Override
    public final N pop() {

        int spin = 0;
        // now pop the stack
        for(;;) {
            final long writeLock = seqLock.tryWriteLock();
            if(writeLock > 0) {
                try {
                    final int stackTop = this.stackTop.get();
                    final int lastRef = stackTop-1;
                    if(stackTop>0) {
                        try {
                            // if we can modify the stack - i.e. nobody else is modifying
                            final N n = stack.get(lastRef);
                            stack.set(lastRef, null);
                            stackNotFullCondition.signal();
                            return n;
                        } finally {
                            this.stackTop.set(lastRef);
                        }
                    } else {
                        return null;
                    }
                } finally {
                    seqLock.unlock(writeLock);
                }
            }

            spin = Condition.progressiveYield(spin);

        }
    }
364894
public final T allocate()
  {
    AtomicInteger topRef = _top;
    
    while (true) {
      final int top = topRef.get();

      if (top <= 0) {
        return null;
      }
      else if (topRef.compareAndSet(top, top - 1)) {
        T value = _freeStack.getAndSet(top - 1, null);
        
        if (value != null) {
          return value;
        }
      }
    }
  }
419229
public StackNode<E> clean() {
        do {
            final StackNode<E> oldTop = top.get();
            if (top.compareAndSet(oldTop, null))
                return oldTop;

        } while (true);
    }
452586
def pop(self):
        """"""
        e = self.data[self.start]
        self.start += 1
        if self.start > 5 and self.start > len(self.data)//2:
            self.data = self.data[self.start:]
            self.start = 0
        return e
450695
public final Node pop()
  {

    m_firstFree--;

    Node n = m_map[m_firstFree];

    m_map[m_firstFree] = null;

    return n;
  }
1187494
public boolean popTable() {
        if (currentLevel > 0) {
            //Remove all the variable having a level equals to currentLevel
            for (Iterator<Map.Entry<String, Integer>> ite = level.entrySet().iterator(); ite.hasNext(); ) {
                Map.Entry<String, Integer> e = ite.next();
                if (e.getValue() == currentLevel) {
                    ite.remove();
                    type.remove(e.getKey());
                }
            }
            currentLevel--;
            return true;
        }
        return false;
    }
1056186
public Object pop()
  {
    Object val = m_map[--m_firstFree];
    m_map[m_firstFree] = null;
    
    return val;
  }
1297026
public T pop()
    {
        T val = beginChunk.values[beginPos];
        beginChunk.values[beginPos] = null;
        beginPos++;
        if (beginPos == size) {
            beginChunk = beginChunk.next;
            beginChunk.prev = null;
            beginPos = 0;
        }
        return val;
    }
112637
public function pop()
    {
        if (isset($this->input[$this->pos])) {
            return $this->input[$this->pos ++];
        }
        return null;
    }
661487
public function pop()
	{
		if($this->_c)
		{
			--$this->_c;
			return array_pop($this->_d);
		}
		else
			throw new CException(Yii::t('yii','The stack is empty.'));
	}
1051993
public function pop() {
        if (null === $this->stack) return null;
        if ($this->isEmpty()) return null;

        $this->size--;
        $value = $this->stack[$this->size];
        return $value;
    }
1305431
public static InsnList pop() {
        InsnList ret = new InsnList();
        ret.add(new InsnNode(Opcodes.POP));

        return ret;
    }
379929
protected String popOrNull(Stack<String> stack) {
        if (stack != null && !stack.isEmpty()) {
            return stack.pop();
        } else {
            return null;
        }
    }
1228582
public T removeLast()
   {
      T element = elementData[--size];
      elementData[size] = null;
      return element;
   }
1025304
public function pop()
    {
        if ($this->count() == 0) {
            return null;
        }
        $ret = $this->getLast();
        $lastKey = $this->getInternalIterator()->key();
        $this->offsetUnset((string) $lastKey);

        return $ret;
    }