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# Source code for astropy.table.soco

    # Licensed under a 3-clause BSD style license - see LICENSE.rst

    """
    The SCEngine class uses the ``sortedcontainers`` package to implement an
    Index engine for Tables.
    """

    from collections import OrderedDict
    from itertools import starmap

    from astropy.utils.compat.optional_deps import HAS_SORTEDCONTAINERS

    if HAS_SORTEDCONTAINERS:
        from sortedcontainers import SortedList

    class Node:
        __slots__ = ("key", "value")

        def __init__(self, key, value):
            self.key = key
            self.value = value

        def __lt__(self, other):
            if other.__class__ is Node:
                return (self.key, self.value) < (other.key, other.value)
            return self.key < other

        def __le__(self, other):
            if other.__class__ is Node:
                return (self.key, self.value) <= (other.key, other.value)
            return self.key <= other

        def __eq__(self, other):
            if other.__class__ is Node:
                return (self.key, self.value) == (other.key, other.value)
            return self.key == other

        def __ne__(self, other):
            if other.__class__ is Node:
                return (self.key, self.value) != (other.key, other.value)
            return self.key != other

        def __gt__(self, other):
            if other.__class__ is Node:
                return (self.key, self.value) > (other.key, other.value)
            return self.key > other

        def __ge__(self, other):
            if other.__class__ is Node:
                return (self.key, self.value) >= (other.key, other.value)
            return self.key >= other

        __hash__ = None

        def __repr__(self):
            return f"Node({self.key!r}, {self.value!r})"

    class SCEngine:
        """
        Fast tree-based implementation for indexing, using the
        ``sortedcontainers`` package.

        Parameters
        ----------
        data : Table
            Sorted columns of the original table
        row_index : Column object
            Row numbers corresponding to data columns
        unique : bool
            Whether the values of the index must be unique.
            Defaults to False.
        """

        def __init__(self, data, row_index, unique=False):
            if not HAS_SORTEDCONTAINERS:
                raise ImportError("sortedcontainers is needed for using SCEngine")

            node_keys = map(tuple, data)
            self._nodes = SortedList(starmap(Node, zip(node_keys, row_index)))
            self._unique = unique

        def add(self, key, value):
            """
            Add a key, value pair.
            """
            if self._unique and (key in self._nodes):
                message = f"duplicate {key!r} in unique index"
                raise ValueError(message)
            self._nodes.add(Node(key, value))

        def find(self, key):
            """
            Find rows corresponding to the given key.
            """
            return [node.value for node in self._nodes.irange(key, key)]

        def remove(self, key, data=None):
            """
            Remove data from the given key.
            """
            if data is not None:
                item = Node(key, data)
                try:
                    self._nodes.remove(item)
                except ValueError:
                    return False
                return True
            items = list(self._nodes.irange(key, key))
            for item in items:
                self._nodes.remove(item)
            return bool(items)

        def shift_left(self, row):
            """
            Decrement rows larger than the given row.
            """
            for node in self._nodes:
                if node.value > row:
                    node.value -= 1

        def shift_right(self, row):
            """
            Increment rows greater than or equal to the given row.
            """
            for node in self._nodes:
                if node.value >= row:
                    node.value += 1

        def items(self):
            """
            Return a list of key, data tuples.
            """
            result = OrderedDict()
            for node in self._nodes:
                if node.key in result:
                    result[node.key].append(node.value)
                else:
                    result[node.key] = [node.value]
            return result.items()

        def sort(self):
            """
            Make row order align with key order.
            """
            for index, node in enumerate(self._nodes):
                node.value = index

        def sorted_data(self):
            """
            Return a list of rows in order sorted by key.
            """
            return [node.value for node in self._nodes]

        def range(self, lower, upper, bounds=(True, True)):
            """
            Return row values in the given range.
            """
            iterator = self._nodes.irange(lower, upper, bounds)
            return [node.value for node in iterator]

        def replace_rows(self, row_map):
            """
            Replace rows with the values in row_map.
            """
            nodes = [node for node in self._nodes if node.value in row_map]
            for node in nodes:
                node.value = row_map[node.value]
            self._nodes.clear()
            self._nodes.update(nodes)

        def __repr__(self):
            if len(self._nodes) > 6:
                nodes = list(self._nodes[:3]) + ["..."] + list(self._nodes[-3:])
            else:
                nodes = self._nodes
            nodes_str = ", ".join(str(node) for node in nodes)
            return f"<{self.__class__.__name__} nodes={nodes_str}>"