"""Implementation of JSONEncoder

"""

import re

c_encode_basestring_ascii = None

c_make_encoder = None

ESCAPE = re.compile(r'[\x00-\x1f\\"\b\f\n\r\t]')

ESCAPE_ASCII = re.compile(r'([\\"]|[^\ -~])')

HAS_UTF8 = re.compile(r'[\x80-\xff]')

ESCAPE_DCT = {

    '\\': '\\\\',

    '"': '\\"',

    '\b': '\\b',

    '\f': '\\f',

    '\n': '\\n',

    '\r': '\\r',

    '\t': '\\t',

}

for i in range(0x20):

    ESCAPE_DCT.setdefault(chr(i), '\\u%04x' % (i,))

# Assume this produces an infinity on all machines (probably not guaranteed)

INFINITY = float('1e66666')

FLOAT_REPR = repr

def encode_basestring(s):

    """Return a JSON representation of a Python string

    """

    def replace(match):

        return ESCAPE_DCT[match.group(0)]

    return '"' + ESCAPE.sub(replace, s) + '"'

def py_encode_basestring_ascii(s):

    """Return an ASCII-only JSON representation of a Python string

    """

    if isinstance(s, str) and HAS_UTF8.search(s) is not None:

        s = s.decode('utf-8')

    def replace(match):

        s = match.group(0)

        try:

            return ESCAPE_DCT[s]

        except KeyError:

            n = ord(s)

            if n < 0x10000:

                return '\\u%04x' % (n,)

            else:

                # surrogate pair

                n -= 0x10000

                s1 = 0xd800 | ((n >> 10) & 0x3ff)

                s2 = 0xdc00 | (n & 0x3ff)

                return '\\u%04x\\u%04x' % (s1, s2)

    return '"' + str(ESCAPE_ASCII.sub(replace, s)) + '"'

encode_basestring_ascii = c_encode_basestring_ascii or py_encode_basestring_ascii

class JSONEncoder(object):

    """Extensible JSON <http://json.org> encoder for Python data structures.

    Supports the following objects and types by default:

    +-------------------+---------------+

    | Python            | JSON          |

    +===================+===============+

    | dict              | object        |

    +-------------------+---------------+

    | list, tuple       | array         |

    +-------------------+---------------+

    | str, unicode      | string        |

    +-------------------+---------------+

    | int, long, float  | number        |

    +-------------------+---------------+

    | True              | true          |

    +-------------------+---------------+

    | False             | false         |

    +-------------------+---------------+

    | None              | null          |

    +-------------------+---------------+

    To extend this to recognize other objects, subclass and implement a

    ``.default()`` method with another method that returns a serializable

    object for ``o`` if possible, otherwise it should call the superclass

    implementation (to raise ``TypeError``).

    """

    item_separator = ', '

    key_separator = ': '

    def __init__(self, skipkeys=False, ensure_ascii=True,

            check_circular=True, allow_nan=True, sort_keys=False,

            indent=None, separators=None, encoding='utf-8', default=None):

        """Constructor for JSONEncoder, with sensible defaults.

        If skipkeys is False, then it is a TypeError to attempt

        encoding of keys that are not str, int, long, float or None.  If

        skipkeys is True, such items are simply skipped.

        If ensure_ascii is True, the output is guaranteed to be str

        objects with all incoming unicode characters escaped.  If

        ensure_ascii is false, the output will be unicode object.

        If check_circular is True, then lists, dicts, and custom encoded

        objects will be checked for circular references during encoding to

        prevent an infinite recursion (which would cause an OverflowError).

        Otherwise, no such check takes place.

        If allow_nan is True, then NaN, Infinity, and -Infinity will be

        encoded as such.  This behavior is not JSON specification compliant,

        but is consistent with most JavaScript based encoders and decoders.

        Otherwise, it will be a ValueError to encode such floats.

        If sort_keys is True, then the output of dictionaries will be

        sorted by key; this is useful for regression tests to ensure

        that JSON serializations can be compared on a day-to-day basis.

        If indent is a non-negative integer, then JSON array

        elements and object members will be pretty-printed with that

        indent level.  An indent level of 0 will only insert newlines.

        None is the most compact representation.

        If specified, separators should be a (item_separator, key_separator)

        tuple.  The default is (', ', ': ').  To get the most compact JSON

        representation you should specify (',', ':') to eliminate whitespace.

        If specified, default is a function that gets called for objects

        that can't otherwise be serialized.  It should return a JSON encodable

        version of the object or raise a ``TypeError``.

        If encoding is not None, then all input strings will be

        transformed into unicode using that encoding prior to JSON-encoding.

        The default is UTF-8.

        """

        self.skipkeys = skipkeys

        self.ensure_ascii = ensure_ascii

        self.check_circular = check_circular

        self.allow_nan = allow_nan

        self.sort_keys = sort_keys

        self.indent = indent

        if separators is not None:

            self.item_separator, self.key_separator = separators

        if default is not None:

            self.default = default

        self.encoding = encoding

    def default(self, o):

        """Implement this method in a subclass such that it returns

        a serializable object for ``o``, or calls the base implementation

        (to raise a ``TypeError``).

        For example, to support arbitrary iterators, you could

        implement default like this::

            def default(self, o):

                try:

                    iterable = iter(o)

                except TypeError:

                    pass

                else:

                    return list(iterable)

                return JSONEncoder.default(self, o)

        """

        raise TypeError("%r is not JSON serializable" % (o,))

    def encode(self, o):

        """Return a JSON string representation of a Python data structure.

        >>> JSONEncoder().encode({"foo": ["bar", "baz"]})

        '{"foo": ["bar", "baz"]}'

        """

        # This is for extremely simple cases and benchmarks.

        if isinstance(o, basestring):

            if isinstance(o, str):

                _encoding = self.encoding

                if (_encoding is not None

                        and not (_encoding == 'utf-8')):

                    o = o.decode(_encoding)

            if self.ensure_ascii:

                return encode_basestring_ascii(o)

            else:

                return encode_basestring(o)

        # This doesn't pass the iterator directly to ''.join() because the

        # exceptions aren't as detailed.  The list call should be roughly

        # equivalent to the PySequence_Fast that ''.join() would do.

        chunks = self.iterencode(o, _one_shot=True)

        if not isinstance(chunks, (list, tuple)):

            chunks = list(chunks)

        return ''.join(chunks)

    def iterencode(self, o, _one_shot=False):

        """Encode the given object and yield each string

        representation as available.

        For example::

            for chunk in JSONEncoder().iterencode(bigobject):

                mysocket.write(chunk)

        """

        if self.check_circular:

            markers = {}

        else:

            markers = None

        if self.ensure_ascii:

            _encoder = encode_basestring_ascii

        else:

            _encoder = encode_basestring

        if self.encoding != 'utf-8':

            def _encoder(o, _orig_encoder=_encoder, _encoding=self.encoding):

                if isinstance(o, str):

                    o = o.decode(_encoding)

                return _orig_encoder(o)

        def floatstr(o, allow_nan=self.allow_nan, _repr=FLOAT_REPR, _inf=INFINITY, _neginf=-INFINITY):

            # Check for specials.  Note that this type of test is processor- and/or

            # platform-specific, so do tests which don't depend on the internals.

            if o != o:

                text = 'NaN'

            elif o == _inf:

                text = 'Infinity'

            elif o == _neginf:

                text = '-Infinity'

            else:

                return _repr(o)

            if not allow_nan:

                raise ValueError("Out of range float values are not JSON compliant: %r"

                    % (o,))

            return text

        if _one_shot and c_make_encoder is not None and not self.indent and not self.sort_keys:

            _iterencode = c_make_encoder(

                markers, self.default, _encoder, self.indent,

                self.key_separator, self.item_separator, self.sort_keys,

                self.skipkeys, self.allow_nan)

        else:

            _iterencode = _make_iterencode(

                markers, self.default, _encoder, self.indent, floatstr,

                self.key_separator, self.item_separator, self.sort_keys,

                self.skipkeys, _one_shot)

        return _iterencode(o, 0)

def _make_iterencode(markers, _default, _encoder, _indent, _floatstr, _key_separator, _item_separator, _sort_keys, _skipkeys, _one_shot,

        ## HACK: hand-optimized bytecode; turn globals into locals

        False=False,

        True=True,

        ValueError=ValueError,

        basestring=basestring,

        dict=dict,

        float=float,

        id=id,

        int=int,

        isinstance=isinstance,

        list=list,

        long=long,

        str=str,

        tuple=tuple,

    ):

    def _iterencode_list(lst, _current_indent_level):

        if not lst:

            yield '[]'

            return

        if markers is not None:

            markerid = id(lst)

            if markerid in markers:

                raise ValueError("Circular reference detected")

            markers[markerid] = lst

        buf = '['

        if _indent is not None:

            _current_indent_level += 1

            newline_indent = '\n' + (' ' * (_indent * _current_indent_level))

            separator = _item_separator + newline_indent

            buf += newline_indent

        else:

            newline_indent = None

            separator = _item_separator

        first = True

        for value in lst:

            if first:

                first = False

            else:

                buf = separator

            if isinstance(value, basestring):

                yield buf + _encoder(value)

            elif value is None:

                yield buf + 'null'

            elif value is True:

                yield buf + 'true'

            elif value is False:

                yield buf + 'false'

            elif isinstance(value, (int, long)):

                yield buf + str(value)

            elif isinstance(value, float):

                yield buf + _floatstr(value)

            else:

                yield buf

                if isinstance(value, (list, tuple)):

                    chunks = _iterencode_list(value, _current_indent_level)

                elif isinstance(value, dict):

                    chunks = _iterencode_dict(value, _current_indent_level)

                else:

                    chunks = _iterencode(value, _current_indent_level)

                for chunk in chunks:

                    yield chunk

        if newline_indent is not None:

            _current_indent_level -= 1

            yield '\n' + (' ' * (_indent * _current_indent_level))

        yield ']'

        if markers is not None:

            del markers[markerid]

    def _iterencode_dict(dct, _current_indent_level):

        if not dct:

            yield '{}'

            return

        if markers is not None:

            markerid = id(dct)

            if markerid in markers:

                raise ValueError("Circular reference detected")

            markers[markerid] = dct

        yield '{'

        if _indent is not None:

            _current_indent_level += 1

            newline_indent = '\n' + (' ' * (_indent * _current_indent_level))

            item_separator = _item_separator + newline_indent

            yield newline_indent

        else:

            newline_indent = None

            item_separator = _item_separator

        first = True

        if _sort_keys:

            items = dct.items()

            items.sort(key=lambda kv: kv[0])

        else:

            items = dct.iteritems()

        for key, value in items:

            if isinstance(key, basestring):

                pass

            # JavaScript is weakly typed for these, so it makes sense to

            # also allow them.  Many encoders seem to do something like this.

            elif isinstance(key, float):

                key = _floatstr(key)

            elif isinstance(key, (int, long)):

                key = str(key)

            elif key is True:

                key = 'true'

            elif key is False:

                key = 'false'

            elif key is None:

                key = 'null'

            elif _skipkeys:

                continue

            else:

                raise TypeError("key %r is not a string" % (key,))

            if first:

                first = False

            else:

                yield item_separator

            yield _encoder(key)

            yield _key_separator

            if isinstance(value, basestring):

                yield _encoder(value)

            elif value is None:

                yield 'null'

            elif value is True:

                yield 'true'

            elif value is False:

                yield 'false'

            elif isinstance(value, (int, long)):

                yield str(value)

            elif isinstance(value, float):

                yield _floatstr(value)

            else:

                if isinstance(value, (list, tuple)):

                    chunks = _iterencode_list(value, _current_indent_level)

                elif isinstance(value, dict):

                    chunks = _iterencode_dict(value, _current_indent_level)

                else:

                    chunks = _iterencode(value, _current_indent_level)

                for chunk in chunks:

                    yield chunk

        if newline_indent is not None:

            _current_indent_level -= 1

            yield '\n' + (' ' * (_indent * _current_indent_level))

        yield '}'

        if markers is not None:

            del markers[markerid]

    def _iterencode(o, _current_indent_level):

        if isinstance(o, basestring):

            yield _encoder(o)

        elif o is None:

            yield 'null'

        elif o is True:

            yield 'true'

        elif o is False:

            yield 'false'

        elif isinstance(o, (int, long)):

            yield str(o)

        elif isinstance(o, float):

            yield _floatstr(o)

        elif isinstance(o, (list, tuple)):

            for chunk in _iterencode_list(o, _current_indent_level):

                yield chunk

        elif isinstance(o, dict):

            for chunk in _iterencode_dict(o, _current_indent_level):