diff --git a/simplejson/encoder.py b/simplejson/encoder.py
new file mode 100644
index 0000000..cab8456
--- /dev/null
+++ b/simplejson/encoder.py
@@ -0,0 +1,501 @@
+"""Implementation of JSONEncoder
+"""
+import re
+from decimal import Decimal
+
+def _import_speedups():
+    try:
+        from simplejson import _speedups
+        return _speedups.encode_basestring_ascii, _speedups.make_encoder
+    except ImportError:
+        return None, None
+c_encode_basestring_ascii, c_make_encoder = _import_speedups()
+
+from simplejson.decoder import PosInf
+
+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{0:04x}'.format(i))
+    ESCAPE_DCT.setdefault(chr(i), '\\u%04x' % (i,))
+
+FLOAT_REPR = repr
+
+def encode_basestring(s):
+    """Return a 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):
+        return ESCAPE_DCT[match.group(0)]
+    return u'"' + ESCAPE.sub(replace, s) + u'"'
+
+
+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{0:04x}'.format(n)
+                return '\\u%04x' % (n,)
+            else:
+                # surrogate pair
+                n -= 0x10000
+                s1 = 0xd800 | ((n >> 10) & 0x3ff)
+                s2 = 0xdc00 | (n & 0x3ff)
+                #return '\\u{0:04x}\\u{1:04x}'.format(s1, s2)
+                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,
+            use_decimal=False):
+        """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 string, then JSON array elements and object members
+        will be pretty-printed with a newline followed by that string repeated
+        for each level of nesting. ``None`` (the default) selects the most compact
+        representation without any newlines. For backwards compatibility with
+        versions of simplejson earlier than 2.1.0, an integer is also accepted
+        and is converted to a string with that many spaces.
+
+        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.
+        
+        If use_decimal is true (not the default), ``decimal.Decimal`` will
+        be supported directly by the encoder. For the inverse, decode JSON
+        with ``parse_float=decimal.Decimal``.
+
+        """
+
+        self.skipkeys = skipkeys
+        self.ensure_ascii = ensure_ascii
+        self.check_circular = check_circular
+        self.allow_nan = allow_nan
+        self.sort_keys = sort_keys
+        self.use_decimal = use_decimal
+        if isinstance(indent, (int, long)):
+            indent = ' ' * indent
+        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(repr(o) + " is not JSON serializable")
+
+    def encode(self, o):
+        """Return a JSON string representation of a Python data structure.
+
+        >>> from simplejson import JSONEncoder
+        >>> 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)
+        if self.ensure_ascii:
+            return ''.join(chunks)
+        else:
+            return u''.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=PosInf, _neginf=-PosInf):
+            # 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: " +
+                    repr(o))
+
+            return text
+
+
+        key_memo = {}
+        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, key_memo, self.use_decimal)
+        else:
+            _iterencode = _make_iterencode(
+                markers, self.default, _encoder, self.indent, floatstr,
+                self.key_separator, self.item_separator, self.sort_keys,
+                self.skipkeys, _one_shot, self.use_decimal)
+        try:
+            return _iterencode(o, 0)
+        finally:
+            key_memo.clear()
+
+
+class JSONEncoderForHTML(JSONEncoder):
+    """An encoder that produces JSON safe to embed in HTML.
+
+    To embed JSON content in, say, a script tag on a web page, the
+    characters &, < and > should be escaped. They cannot be escaped
+    with the usual entities (e.g. &amp;) because they are not expanded
+    within <script> tags.
+    """
+
+    def encode(self, o):
+        # Override JSONEncoder.encode because it has hacks for
+        # performance that make things more complicated.
+        chunks = self.iterencode(o, True)
+        if self.ensure_ascii:
+            return ''.join(chunks)
+        else:
+            return u''.join(chunks)
+
+    def iterencode(self, o, _one_shot=False):
+        chunks = super(JSONEncoderForHTML, self).iterencode(o, _one_shot)
+        for chunk in chunks:
+            chunk = chunk.replace('&', '\\u0026')
+            chunk = chunk.replace('<', '\\u003c')
+            chunk = chunk.replace('>', '\\u003e')
+            yield chunk
+
+
+def _make_iterencode(markers, _default, _encoder, _indent, _floatstr,
+        _key_separator, _item_separator, _sort_keys, _skipkeys, _one_shot,
+        _use_decimal,
+        ## HACK: hand-optimized bytecode; turn globals into locals
+        False=False,
+        True=True,
+        ValueError=ValueError,
+        basestring=basestring,
+        Decimal=Decimal,
+        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)
+            elif _use_decimal and isinstance(value, Decimal):
+                yield buf + str(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 key is True:
+                key = 'true'
+            elif key is False:
+                key = 'false'
+            elif key is None:
+                key = 'null'
+            elif isinstance(key, (int, long)):
+                key = str(key)
+            elif _skipkeys:
+                continue
+            else:
+                raise TypeError("key " + repr(key) + " is not a string")
+            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)
+            elif _use_decimal and isinstance(value, Decimal):
+                yield str(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):
+                yield chunk
+        elif _use_decimal and isinstance(o, Decimal):
+            yield str(o)
+        else:
+            if markers is not None:
+                markerid = id(o)
+                if markerid in markers:
+                    raise ValueError("Circular reference detected")
+                markers[markerid] = o
+            o = _default(o)
+            for chunk in _iterencode(o, _current_indent_level):
+                yield chunk
+            if markers is not None:
+                del markers[markerid]
+
+    return _iterencode