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"""Fallback pure Python implementation of msgpack"""

import struct
import sys
from datetime import datetime as _DateTime

if hasattr(sys, "pypy_version_info"):
    from __pypy__ import newlist_hint
    from __pypy__.builders import BytesBuilder

    _USING_STRINGBUILDER = True

    class BytesIO:
        def __init__(self, s=b""):
            if s:
                self.builder = BytesBuilder(len(s))
                self.builder.append(s)
            else:
                self.builder = BytesBuilder()

        def write(self, s):
            if isinstance(s, memoryview):
                s = s.tobytes()
            elif isinstance(s, bytearray):
                s = bytes(s)
            self.builder.append(s)

        def getvalue(self):
            return self.builder.build()

else:
    from io import BytesIO

    _USING_STRINGBUILDER = False

    def newlist_hint(size):
        return []


from .exceptions import BufferFull, ExtraData, FormatError, OutOfData, StackError
from .ext import ExtType, Timestamp

EX_SKIP = 0
EX_CONSTRUCT = 1
EX_READ_ARRAY_HEADER = 2
EX_READ_MAP_HEADER = 3

TYPE_IMMEDIATE = 0
TYPE_ARRAY = 1
TYPE_MAP = 2
TYPE_RAW = 3
TYPE_BIN = 4
TYPE_EXT = 5

DEFAULT_RECURSE_LIMIT = 1024


def _check_type_strict(obj, t, type=type, tuple=tuple):
    if type(t) is tuple:
        return type(obj) in t
    else:
        return type(obj) is t


def _get_data_from_buffer(obj):
    view = memoryview(obj)
    if view.itemsize != 1:
        raise ValueError("cannot unpack from multi-byte object")
    return view


def unpackb(packed, **kwargs):
    """
    Unpack an object from `packed`.

    Raises ``ExtraData`` when *packed* contains extra bytes.
    Raises ``ValueError`` when *packed* is incomplete.
    Raises ``FormatError`` when *packed* is not valid msgpack.
    Raises ``StackError`` when *packed* contains too nested.
    Other exceptions can be raised during unpacking.

    See :class:`Unpacker` for options.
    """
    unpacker = Unpacker(None, max_buffer_size=len(packed), **kwargs)
    unpacker.feed(packed)
    try:
        ret = unpacker._unpack()
    except OutOfData:
        raise ValueError("Unpack failed: incomplete input")
    except RecursionError:
        raise StackError
    if unpacker._got_extradata():
        raise ExtraData(ret, unpacker._get_extradata())
    return ret


_NO_FORMAT_USED = ""
_MSGPACK_HEADERS = {
    0xC4: (1, _NO_FORMAT_USED, TYPE_BIN),
    0xC5: (2, ">H", TYPE_BIN),
    0xC6: (4, ">I", TYPE_BIN),
    0xC7: (2, "Bb", TYPE_EXT),
    0xC8: (3, ">Hb", TYPE_EXT),
    0xC9: (5, ">Ib", TYPE_EXT),
    0xCA: (4, ">f"),
    0xCB: (8, ">d"),
    0xCC: (1, _NO_FORMAT_USED),
    0xCD: (2, ">H"),
    0xCE: (4, ">I"),
    0xCF: (8, ">Q"),
    0xD0: (1, "b"),
    0xD1: (2, ">h"),
    0xD2: (4, ">i"),
    0xD3: (8, ">q"),
    0xD4: (1, "b1s", TYPE_EXT),
    0xD5: (2, "b2s", TYPE_EXT),
    0xD6: (4, "b4s", TYPE_EXT),
    0xD7: (8, "b8s", TYPE_EXT),
    0xD8: (16, "b16s", TYPE_EXT),
    0xD9: (1, _NO_FORMAT_USED, TYPE_RAW),
    0xDA: (2, ">H", TYPE_RAW),
    0xDB: (4, ">I", TYPE_RAW),
    0xDC: (2, ">H", TYPE_ARRAY),
    0xDD: (4, ">I", TYPE_ARRAY),
    0xDE: (2, ">H", TYPE_MAP),
    0xDF: (4, ">I", TYPE_MAP),
}


class Unpacker:
    """Streaming unpacker.

    Arguments:

    :param file_like:
        File-like object having `.read(n)` method.
        If specified, unpacker reads serialized data from it and `.feed()` is not usable.

    :param int read_size:
        Used as `file_like.read(read_size)`. Must be equal to or smaller than *max_buffer_size*.

    :param bool use_list:
        If true, unpack msgpack array to Python list.
        Otherwise, unpack to Python tuple. (default: True)

    :param bool raw:
        If true, unpack msgpack raw to Python bytes.
        Otherwise, unpack to Python str by decoding with UTF-8 encoding (default).

    :param int timestamp:
        Control how timestamp type is unpacked:

            0 - Timestamp
            1 - float  (Seconds from the EPOCH)
            2 - int  (Nanoseconds from the EPOCH)
            3 - datetime.datetime  (UTC).

    :param bool strict_map_key:
        If true (default), only str or bytes are accepted for map (dict) keys.

    :param object_hook:
        When specified, it should be callable.
        Unpacker calls it with a dict argument after unpacking msgpack map.
        (See also simplejson)

    :param object_pairs_hook:
        When specified, it should be callable.
        Unpacker calls it with a list of key-value pairs after unpacking msgpack map.
        (See also simplejson)

    :param str unicode_errors:
        The error handler for decoding unicode. (default: 'strict')
        This option should be used only when you have msgpack data which
        contains invalid UTF-8 string.

    :param int max_buffer_size:
        Limits size of data waiting unpacked.  0 means 2**32-1.
        The default value is 100*1024*1024 (100MiB).
        Raises `BufferFull` exception when it is insufficient.
        You should set this parameter when unpacking data from untrusted source.

    :param int max_str_len:
        Deprecated, use *max_buffer_size* instead.
        Limits max length of str. (default: max_buffer_size)

    :param int max_bin_len:
        Deprecated, use *max_buffer_size* instead.
        Limits max length of bin. (default: max_buffer_size)

    :param int max_array_len:
        Limits max length of array.
        (default: max_buffer_size)

    :param int max_map_len:
        Limits max length of map.
        (default: max_buffer_size//2)

    :param int max_ext_len:
        Deprecated, use *max_buffer_size* instead.
        Limits max size of ext type.  (default: max_buffer_size)

    Example of streaming deserialize from file-like object::

        unpacker = Unpacker(file_like)
        for o in unpacker:
            process(o)

    Example of streaming deserialize from socket::

        unpacker = Unpacker()
        while True:
            buf = sock.recv(1024**2)
            if not buf:
                break
            unpacker.feed(buf)
            for o in unpacker:
                process(o)

    Raises ``ExtraData`` when *packed* contains extra bytes.
    Raises ``OutOfData`` when *packed* is incomplete.
    Raises ``FormatError`` when *packed* is not valid msgpack.
    Raises ``StackError`` when *packed* contains too nested.
    Other exceptions can be raised during unpacking.
    """

    def __init__(
        self,
        file_like=None,
        *,
        read_size=0,
        use_list=True,
        raw=False,
        timestamp=0,
        strict_map_key=True,
        object_hook=None,
        object_pairs_hook=None,
        list_hook=None,
        unicode_errors=None,
        max_buffer_size=100 * 1024 * 1024,
        ext_hook=ExtType,
        max_str_len=-1,
        max_bin_len=-1,
        max_array_len=-1,
        max_map_len=-1,
        max_ext_len=-1,
    ):
        if unicode_errors is None:
            unicode_errors = "strict"

        if file_like is None:
            self._feeding = True
        else:
            if not callable(file_like.read):
                raise TypeError("`file_like.read` must be callable")
            self.file_like = file_like
            self._feeding = False

        #: array of bytes fed.
        self._buffer = bytearray()
        #: Which position we currently reads
        self._buff_i = 0

        # When Unpacker is used as an iterable, between the calls to next(),
        # the buffer is not "consumed" completely, for efficiency sake.
        # Instead, it is done sloppily.  To make sure we raise BufferFull at
        # the correct moments, we have to keep track of how sloppy we were.
        # Furthermore, when the buffer is incomplete (that is: in the case
        # we raise an OutOfData) we need to rollback the buffer to the correct
        # state, which _buf_checkpoint records.
        self._buf_checkpoint = 0

        if not max_buffer_size:
            max_buffer_size = 2**31 - 1
        if max_str_len == -1:
            max_str_len = max_buffer_size
        if max_bin_len == -1:
            max_bin_len = max_buffer_size
        if max_array_len == -1:
            max_array_len = max_buffer_size
        if max_map_len == -1:
            max_map_len = max_buffer_size // 2
        if max_ext_len == -1:
            max_ext_len = max_buffer_size

        self._max_buffer_size = max_buffer_size
        if read_size > self._max_buffer_size:
            raise ValueError("read_size must be smaller than max_buffer_size")
        self._read_size = read_size or min(self._max_buffer_size, 16 * 1024)
        self._raw = bool(raw)
        self._strict_map_key = bool(strict_map_key)
        self._unicode_errors = unicode_errors
        self._use_list = use_list
        if not (0  0:
            del self._buffer[: self._buf_checkpoint]
            self._buff_i -= self._buf_checkpoint
            self._buf_checkpoint = 0

        # Use extend here: INPLACE_ADD += doesn't reliably typecast memoryview in jython
        self._buffer.extend(view if view.contiguous else view.tobytes())
        view.release()

    def _consume(self):
        """Gets rid of the used parts of the buffer."""
        self._stream_offset += self._buff_i - self._buf_checkpoint
        self._buf_checkpoint = self._buff_i

    def _got_extradata(self):
        return self._buff_i < len(self._buffer)

    def _get_extradata(self):
        return self._buffer[self._buff_i :]

    def read_bytes(self, n):
        ret = self._read(n, raise_outofdata=False)
        self._consume()
        return ret

    def _read(self, n, raise_outofdata=True):
        # (int) -> bytearray
        self._reserve(n, raise_outofdata=raise_outofdata)
        i = self._buff_i
        ret = self._buffer[i : i + n]
        self._buff_i = i + len(ret)
        return ret

    def _reserve(self, n, raise_outofdata=True):
        remain_bytes = len(self._buffer) - self._buff_i - n

        # Fast path: buffer has n bytes already
        if remain_bytes >= 0:
            return

        if self._feeding:
            self._buff_i = self._buf_checkpoint
            raise OutOfData

        # Strip buffer before checkpoint before reading file.
        if self._buf_checkpoint > 0:
            del self._buffer[: self._buf_checkpoint]
            self._buff_i -= self._buf_checkpoint
            self._buf_checkpoint = 0

        # Read from file
        remain_bytes = -remain_bytes
        if remain_bytes + len(self._buffer) > self._max_buffer_size:
            raise BufferFull
        while remain_bytes > 0:
            to_read_bytes = max(self._read_size, remain_bytes)
            read_data = self.file_like.read(to_read_bytes)
            if not read_data:
                break
            assert isinstance(read_data, bytes)
            self._buffer += read_data
            remain_bytes -= len(read_data)

        if len(self._buffer) < n + self._buff_i and raise_outofdata:
            self._buff_i = 0  # rollback
            raise OutOfData

    def _read_header(self):
        typ = TYPE_IMMEDIATE
        n = 0
        obj = None
        self._reserve(1)
        b = self._buffer[self._buff_i]
        self._buff_i += 1
        if b & 0b10000000 == 0:
            obj = b
        elif b & 0b11100000 == 0b11100000:
            obj = -1 - (b ^ 0xFF)
        elif b & 0b11100000 == 0b10100000:
            n = b & 0b00011111
            typ = TYPE_RAW
            if n > self._max_str_len:
                raise ValueError(f"{n} exceeds max_str_len({self._max_str_len})")
            obj = self._read(n)
        elif b & 0b11110000 == 0b10010000:
            n = b & 0b00001111
            typ = TYPE_ARRAY
            if n > self._max_array_len:
                raise ValueError(f"{n} exceeds max_array_len({self._max_array_len})")
        elif b & 0b11110000 == 0b10000000:
            n = b & 0b00001111
            typ = TYPE_MAP
            if n > self._max_map_len:
                raise ValueError(f"{n} exceeds max_map_len({self._max_map_len})")
        elif b == 0xC0:
            obj = None
        elif b == 0xC2:
            obj = False
        elif b == 0xC3:
            obj = True
        elif 0xC4  self._max_bin_len:
                raise ValueError(f"{n} exceeds max_bin_len({self._max_bin_len})")
            obj = self._read(n)
        elif 0xC7 

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