Commits

Bob Ippolito committed d95e5ad

merge json library with simplejson 2.0.9 (issue 4136)

Comments (0)

Files changed (13)

Lib/json/__init__.py

-r"""A simple, fast, extensible JSON encoder and decoder
-
-JSON (JavaScript Object Notation) <http://json.org> is a subset of
+r"""JSON (JavaScript Object Notation) <http://json.org> is a subset of
 JavaScript syntax (ECMA-262 3rd edition) used as a lightweight data
 interchange format.
 
-json exposes an API familiar to uses of the standard library
-marshal and pickle modules.
+:mod:`json` exposes an API familiar to users of the standard library
+:mod:`marshal` and :mod:`pickle` modules. It is the externally maintained
+version of the :mod:`json` library contained in Python 2.6, but maintains
+compatibility with Python 2.4 and Python 2.5 and (currently) has
+significant performance advantages, even without using the optional C
+extension for speedups.
 
 Encoding basic Python object hierarchies::
 
     >>> json.dumps([1,2,3,{'4': 5, '6': 7}], separators=(',',':'))
     '[1,2,3,{"4":5,"6":7}]'
 
-Pretty printing (using repr() because of extraneous whitespace in the output)::
+Pretty printing::
 
     >>> import json
-    >>> print repr(json.dumps({'4': 5, '6': 7}, sort_keys=True, indent=4))
-    '{\n    "4": 5, \n    "6": 7\n}'
+    >>> s = json.dumps({'4': 5, '6': 7}, sort_keys=True, indent=4)
+    >>> print '\n'.join([l.rstrip() for l in  s.splitlines()])
+    {
+        "4": 5,
+        "6": 7
+    }
 
 Decoding JSON::
 
     >>> import json
-    >>> json.loads('["foo", {"bar":["baz", null, 1.0, 2]}]')
-    [u'foo', {u'bar': [u'baz', None, 1.0, 2]}]
-    >>> json.loads('"\\"foo\\bar"')
-    u'"foo\x08ar'
+    >>> obj = [u'foo', {u'bar': [u'baz', None, 1.0, 2]}]
+    >>> json.loads('["foo", {"bar":["baz", null, 1.0, 2]}]') == obj
+    True
+    >>> json.loads('"\\"foo\\bar"') == u'"foo\x08ar'
+    True
     >>> from StringIO import StringIO
     >>> io = StringIO('["streaming API"]')
-    >>> json.load(io)
-    [u'streaming API']
+    >>> json.load(io)[0] == 'streaming API'
+    True
 
 Specializing JSON object decoding::
 
     >>> json.loads('{"__complex__": true, "real": 1, "imag": 2}',
     ...     object_hook=as_complex)
     (1+2j)
-    >>> import decimal
-    >>> json.loads('1.1', parse_float=decimal.Decimal)
-    Decimal('1.1')
+    >>> from decimal import Decimal
+    >>> json.loads('1.1', parse_float=Decimal) == Decimal('1.1')
+    True
 
-Extending JSONEncoder::
+Specializing JSON object encoding::
 
     >>> import json
-    >>> class ComplexEncoder(json.JSONEncoder):
-    ...     def default(self, obj):
-    ...         if isinstance(obj, complex):
-    ...             return [obj.real, obj.imag]
-    ...         return json.JSONEncoder.default(self, obj)
+    >>> def encode_complex(obj):
+    ...     if isinstance(obj, complex):
+    ...         return [obj.real, obj.imag]
+    ...     raise TypeError(repr(o) + " is not JSON serializable")
     ...
-    >>> dumps(2 + 1j, cls=ComplexEncoder)
+    >>> json.dumps(2 + 1j, default=encode_complex)
     '[2.0, 1.0]'
-    >>> ComplexEncoder().encode(2 + 1j)
+    >>> json.JSONEncoder(default=encode_complex).encode(2 + 1j)
     '[2.0, 1.0]'
-    >>> list(ComplexEncoder().iterencode(2 + 1j))
-    ['[', '2.0', ', ', '1.0', ']']
+    >>> ''.join(json.JSONEncoder(default=encode_complex).iterencode(2 + 1j))
+    '[2.0, 1.0]'
 
 
-Using json.tool from the shell to validate and
-pretty-print::
+Using json.tool from the shell to validate and pretty-print::
 
-    $ echo '{"json":"obj"}' | python -mjson.tool
+    $ echo '{"json":"obj"}' | python -m json.tool
     {
         "json": "obj"
     }
-    $ echo '{ 1.2:3.4}' | python -mjson.tool
+    $ echo '{ 1.2:3.4}' | python -m json.tool
     Expecting property name: line 1 column 2 (char 2)
-
-Note that the JSON produced by this module's default settings
-is a subset of YAML, so it may be used as a serializer for that as well.
-
 """
-
-__version__ = '1.9'
+__version__ = '2.0.9'
 __all__ = [
     'dump', 'dumps', 'load', 'loads',
     'JSONDecoder', 'JSONEncoder',
     """Serialize ``obj`` as a JSON formatted stream to ``fp`` (a
     ``.write()``-supporting file-like object).
 
-    If ``skipkeys`` is ``True`` then ``dict`` keys that are not basic types
+    If ``skipkeys`` is true then ``dict`` keys that are not basic types
     (``str``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``)
     will be skipped instead of raising a ``TypeError``.
 
-    If ``ensure_ascii`` is ``False``, then the some chunks written to ``fp``
+    If ``ensure_ascii`` is false, then the some chunks written to ``fp``
     may be ``unicode`` instances, subject to normal Python ``str`` to
     ``unicode`` coercion rules. Unless ``fp.write()`` explicitly
     understands ``unicode`` (as in ``codecs.getwriter()``) this is likely
     to cause an error.
 
-    If ``check_circular`` is ``False``, then the circular reference check
+    If ``check_circular`` is false, then the circular reference check
     for container types will be skipped and a circular reference will
     result in an ``OverflowError`` (or worse).
 
-    If ``allow_nan`` is ``False``, then it will be a ``ValueError`` to
+    If ``allow_nan`` is false, then it will be a ``ValueError`` to
     serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``)
     in strict compliance of the JSON specification, instead of using the
     JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``).
 
-    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 ``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 ``separators`` is an ``(item_separator, dict_separator)`` tuple
     then it will be used instead of the default ``(', ', ': ')`` separators.
 
     """
     # cached encoder
-    if (skipkeys is False and ensure_ascii is True and
-        check_circular is True and allow_nan is True and
+    if (not skipkeys and ensure_ascii and
+        check_circular and allow_nan and
         cls is None and indent is None and separators is None and
         encoding == 'utf-8' and default is None and not kw):
         iterable = _default_encoder.iterencode(obj)
         encoding='utf-8', default=None, **kw):
     """Serialize ``obj`` to a JSON formatted ``str``.
 
-    If ``skipkeys`` is ``True`` then ``dict`` keys that are not basic types
+    If ``skipkeys`` is false then ``dict`` keys that are not basic types
     (``str``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``)
     will be skipped instead of raising a ``TypeError``.
 
-    If ``ensure_ascii`` is ``False``, then the return value will be a
+    If ``ensure_ascii`` is false, then the return value will be a
     ``unicode`` instance subject to normal Python ``str`` to ``unicode``
     coercion rules instead of being escaped to an ASCII ``str``.
 
-    If ``check_circular`` is ``False``, then the circular reference check
+    If ``check_circular`` is false, then the circular reference check
     for container types will be skipped and a circular reference will
     result in an ``OverflowError`` (or worse).
 
-    If ``allow_nan`` is ``False``, then it will be a ``ValueError`` to
+    If ``allow_nan`` is false, then it will be a ``ValueError`` to
     serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``) in
     strict compliance of the JSON specification, instead of using the
     JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``).
 
     """
     # cached encoder
-    if (skipkeys is False and ensure_ascii is True and
-        check_circular is True and allow_nan is True and
+    if (not skipkeys and ensure_ascii and
+        check_circular and allow_nan and
         cls is None and indent is None and separators is None and
         encoding == 'utf-8' and default is None and not kw):
         return _default_encoder.encode(obj)
 
 def load(fp, encoding=None, cls=None, object_hook=None, parse_float=None,
         parse_int=None, parse_constant=None, **kw):
-    """Deserialize ``fp`` (a ``.read()``-supporting file-like object
-    containing a JSON document) to a Python object.
+    """Deserialize ``fp`` (a ``.read()``-supporting file-like object containing
+    a JSON document) to a Python object.
 
     If the contents of ``fp`` is encoded with an ASCII based encoding other
     than utf-8 (e.g. latin-1), then an appropriate ``encoding`` name must

Lib/json/decoder.py

 """Implementation of JSONDecoder
 """
-
 import re
 import sys
+import struct
 
-from json.scanner import Scanner, pattern
+from json.scanner import make_scanner
 try:
     from _json import scanstring as c_scanstring
 except ImportError:
 
 FLAGS = re.VERBOSE | re.MULTILINE | re.DOTALL
 
-NaN, PosInf, NegInf = float('nan'), float('inf'), float('-inf')
+def _floatconstants():
+    _BYTES = '7FF80000000000007FF0000000000000'.decode('hex')
+    if sys.byteorder != 'big':
+        _BYTES = _BYTES[:8][::-1] + _BYTES[8:][::-1]
+    nan, inf = struct.unpack('dd', _BYTES)
+    return nan, inf, -inf
+
+NaN, PosInf, NegInf = _floatconstants()
 
 
 def linecol(doc, pos):
 
 
 def errmsg(msg, doc, pos, end=None):
+    # Note that this function is called from _json
     lineno, colno = linecol(doc, pos)
     if end is None:
         fmt = '{0}: line {1} column {2} (char {3})'
         return fmt.format(msg, lineno, colno, pos)
+        #fmt = '%s: line %d column %d (char %d)'
+        #return fmt % (msg, lineno, colno, pos)
     endlineno, endcolno = linecol(doc, end)
     fmt = '{0}: line {1} column {2} - line {3} column {4} (char {5} - {6})'
     return fmt.format(msg, lineno, colno, endlineno, endcolno, pos, end)
+    #fmt = '%s: line %d column %d - line %d column %d (char %d - %d)'
+    #return fmt % (msg, lineno, colno, endlineno, endcolno, pos, end)
 
 
 _CONSTANTS = {
     '-Infinity': NegInf,
     'Infinity': PosInf,
     'NaN': NaN,
-    'true': True,
-    'false': False,
-    'null': None,
 }
 
-
-def JSONConstant(match, context, c=_CONSTANTS):
-    s = match.group(0)
-    fn = getattr(context, 'parse_constant', None)
-    if fn is None:
-        rval = c[s]
-    else:
-        rval = fn(s)
-    return rval, None
-pattern('(-?Infinity|NaN|true|false|null)')(JSONConstant)
-
-
-def JSONNumber(match, context):
-    match = JSONNumber.regex.match(match.string, *match.span())
-    integer, frac, exp = match.groups()
-    if frac or exp:
-        fn = getattr(context, 'parse_float', None) or float
-        res = fn(integer + (frac or '') + (exp or ''))
-    else:
-        fn = getattr(context, 'parse_int', None) or int
-        res = fn(integer)
-    return res, None
-pattern(r'(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]?\d+)?')(JSONNumber)
-
-
 STRINGCHUNK = re.compile(r'(.*?)(["\\\x00-\x1f])', FLAGS)
 BACKSLASH = {
     '"': u'"', '\\': u'\\', '/': u'/',
 
 DEFAULT_ENCODING = "utf-8"
 
+def py_scanstring(s, end, encoding=None, strict=True,
+        _b=BACKSLASH, _m=STRINGCHUNK.match):
+    """Scan the string s for a JSON string. End is the index of the
+    character in s after the quote that started the JSON string.
+    Unescapes all valid JSON string escape sequences and raises ValueError
+    on attempt to decode an invalid string. If strict is False then literal
+    control characters are allowed in the string.
 
-def py_scanstring(s, end, encoding=None, strict=True, _b=BACKSLASH, _m=STRINGCHUNK.match):
+    Returns a tuple of the decoded string and the index of the character in s
+    after the end quote."""
     if encoding is None:
         encoding = DEFAULT_ENCODING
     chunks = []
                 errmsg("Unterminated string starting at", s, begin))
         end = chunk.end()
         content, terminator = chunk.groups()
+        # Content is contains zero or more unescaped string characters
         if content:
             if not isinstance(content, unicode):
                 content = unicode(content, encoding)
             _append(content)
+        # Terminator is the end of string, a literal control character,
+        # or a backslash denoting that an escape sequence follows
         if terminator == '"':
             break
         elif terminator != '\\':
             if strict:
+                #msg = "Invalid control character %r at" % (terminator,)
                 msg = "Invalid control character {0!r} at".format(terminator)
                 raise ValueError(errmsg(msg, s, end))
             else:
         except IndexError:
             raise ValueError(
                 errmsg("Unterminated string starting at", s, begin))
+        # If not a unicode escape sequence, must be in the lookup table
         if esc != 'u':
             try:
-                m = _b[esc]
+                char = _b[esc]
             except KeyError:
-                msg = "Invalid \\escape: {0!r}".format(esc)
+                msg = "Invalid \\escape: " + repr(esc)
                 raise ValueError(errmsg(msg, s, end))
             end += 1
         else:
+            # Unicode escape sequence
             esc = s[end + 1:end + 5]
             next_end = end + 5
-            msg = "Invalid \\uXXXX escape"
-            try:
-                if len(esc) != 4:
-                    raise ValueError
-                uni = int(esc, 16)
-                if 0xd800 <= uni <= 0xdbff and sys.maxunicode > 65535:
-                    msg = "Invalid \\uXXXX\\uXXXX surrogate pair"
-                    if not s[end + 5:end + 7] == '\\u':
-                        raise ValueError
-                    esc2 = s[end + 7:end + 11]
-                    if len(esc2) != 4:
-                        raise ValueError
-                    uni2 = int(esc2, 16)
-                    uni = 0x10000 + (((uni - 0xd800) << 10) | (uni2 - 0xdc00))
-                    next_end += 6
-                m = unichr(uni)
-            except ValueError:
+            if len(esc) != 4:
+                msg = "Invalid \\uXXXX escape"
                 raise ValueError(errmsg(msg, s, end))
+            uni = int(esc, 16)
+            # Check for surrogate pair on UCS-4 systems
+            if 0xd800 <= uni <= 0xdbff and sys.maxunicode > 65535:
+                msg = "Invalid \\uXXXX\\uXXXX surrogate pair"
+                if not s[end + 5:end + 7] == '\\u':
+                    raise ValueError(errmsg(msg, s, end))
+                esc2 = s[end + 7:end + 11]
+                if len(esc2) != 4:
+                    raise ValueError(errmsg(msg, s, end))
+                uni2 = int(esc2, 16)
+                uni = 0x10000 + (((uni - 0xd800) << 10) | (uni2 - 0xdc00))
+                next_end += 6
+            char = unichr(uni)
             end = next_end
-        _append(m)
+        # Append the unescaped character
+        _append(char)
     return u''.join(chunks), end
 
 
-# Use speedup
-if c_scanstring is not None:
-    scanstring = c_scanstring
-else:
-    scanstring = py_scanstring
+# Use speedup if available
+scanstring = c_scanstring or py_scanstring
 
-def JSONString(match, context):
-    encoding = getattr(context, 'encoding', None)
-    strict = getattr(context, 'strict', True)
-    return scanstring(match.string, match.end(), encoding, strict)
-pattern(r'"')(JSONString)
+WHITESPACE = re.compile(r'[ \t\n\r]*', FLAGS)
+WHITESPACE_STR = ' \t\n\r'
 
-
-WHITESPACE = re.compile(r'\s*', FLAGS)
-
-
-def JSONObject(match, context, _w=WHITESPACE.match):
+def JSONObject((s, end), encoding, strict, scan_once, object_hook,
+        _w=WHITESPACE.match, _ws=WHITESPACE_STR):
     pairs = {}
-    s = match.string
-    end = _w(s, match.end()).end()
+    # Use a slice to prevent IndexError from being raised, the following
+    # check will raise a more specific ValueError if the string is empty
     nextchar = s[end:end + 1]
-    # Trivial empty object
-    if nextchar == '}':
-        return pairs, end + 1
+    # Normally we expect nextchar == '"'
     if nextchar != '"':
-        raise ValueError(errmsg("Expecting property name", s, end))
+        if nextchar in _ws:
+            end = _w(s, end).end()
+            nextchar = s[end:end + 1]
+        # Trivial empty object
+        if nextchar == '}':
+            return pairs, end + 1
+        elif nextchar != '"':
+            raise ValueError(errmsg("Expecting property name", s, end))
     end += 1
-    encoding = getattr(context, 'encoding', None)
-    strict = getattr(context, 'strict', True)
-    iterscan = JSONScanner.iterscan
     while True:
         key, end = scanstring(s, end, encoding, strict)
-        end = _w(s, end).end()
+
+        # To skip some function call overhead we optimize the fast paths where
+        # the JSON key separator is ": " or just ":".
         if s[end:end + 1] != ':':
-            raise ValueError(errmsg("Expecting : delimiter", s, end))
-        end = _w(s, end + 1).end()
+            end = _w(s, end).end()
+            if s[end:end + 1] != ':':
+                raise ValueError(errmsg("Expecting : delimiter", s, end))
+
+        end += 1
+
         try:
-            value, end = iterscan(s, idx=end, context=context).next()
+            if s[end] in _ws:
+                end += 1
+                if s[end] in _ws:
+                    end = _w(s, end + 1).end()
+        except IndexError:
+            pass
+
+        try:
+            value, end = scan_once(s, end)
         except StopIteration:
             raise ValueError(errmsg("Expecting object", s, end))
         pairs[key] = value
-        end = _w(s, end).end()
-        nextchar = s[end:end + 1]
+
+        try:
+            nextchar = s[end]
+            if nextchar in _ws:
+                end = _w(s, end + 1).end()
+                nextchar = s[end]
+        except IndexError:
+            nextchar = ''
         end += 1
+
         if nextchar == '}':
             break
-        if nextchar != ',':
+        elif nextchar != ',':
             raise ValueError(errmsg("Expecting , delimiter", s, end - 1))
-        end = _w(s, end).end()
-        nextchar = s[end:end + 1]
+
+        try:
+            nextchar = s[end]
+            if nextchar in _ws:
+                end += 1
+                nextchar = s[end]
+                if nextchar in _ws:
+                    end = _w(s, end + 1).end()
+                    nextchar = s[end]
+        except IndexError:
+            nextchar = ''
+
         end += 1
         if nextchar != '"':
             raise ValueError(errmsg("Expecting property name", s, end - 1))
-    object_hook = getattr(context, 'object_hook', None)
+
     if object_hook is not None:
         pairs = object_hook(pairs)
     return pairs, end
-pattern(r'{')(JSONObject)
 
-
-def JSONArray(match, context, _w=WHITESPACE.match):
+def JSONArray((s, end), scan_once, _w=WHITESPACE.match, _ws=WHITESPACE_STR):
     values = []
-    s = match.string
-    end = _w(s, match.end()).end()
+    nextchar = s[end:end + 1]
+    if nextchar in _ws:
+        end = _w(s, end + 1).end()
+        nextchar = s[end:end + 1]
     # Look-ahead for trivial empty array
-    nextchar = s[end:end + 1]
     if nextchar == ']':
         return values, end + 1
-    iterscan = JSONScanner.iterscan
+    _append = values.append
     while True:
         try:
-            value, end = iterscan(s, idx=end, context=context).next()
+            value, end = scan_once(s, end)
         except StopIteration:
             raise ValueError(errmsg("Expecting object", s, end))
-        values.append(value)
-        end = _w(s, end).end()
+        _append(value)
         nextchar = s[end:end + 1]
+        if nextchar in _ws:
+            end = _w(s, end + 1).end()
+            nextchar = s[end:end + 1]
         end += 1
         if nextchar == ']':
             break
-        if nextchar != ',':
+        elif nextchar != ',':
             raise ValueError(errmsg("Expecting , delimiter", s, end))
-        end = _w(s, end).end()
+
+        try:
+            if s[end] in _ws:
+                end += 1
+                if s[end] in _ws:
+                    end = _w(s, end + 1).end()
+        except IndexError:
+            pass
+
     return values, end
-pattern(r'\[')(JSONArray)
-
-
-ANYTHING = [
-    JSONObject,
-    JSONArray,
-    JSONString,
-    JSONConstant,
-    JSONNumber,
-]
-
-JSONScanner = Scanner(ANYTHING)
-
 
 class JSONDecoder(object):
     """Simple JSON <http://json.org> decoder
 
     It also understands ``NaN``, ``Infinity``, and ``-Infinity`` as
     their corresponding ``float`` values, which is outside the JSON spec.
+
     """
 
-    _scanner = Scanner(ANYTHING)
-    __all__ = ['__init__', 'decode', 'raw_decode']
-
     def __init__(self, encoding=None, object_hook=None, parse_float=None,
             parse_int=None, parse_constant=None, strict=True):
         """``encoding`` determines the encoding used to interpret any ``str``
         Note that currently only encodings that are a superset of ASCII work,
         strings of other encodings should be passed in as ``unicode``.
 
-        ``object_hook``, if specified, will be called with the result of
-        every JSON object decoded and its return value will be used in
+        ``object_hook``, if specified, will be called with the result
+        of every JSON object decoded and its return value will be used in
         place of the given ``dict``.  This can be used to provide custom
         deserializations (e.g. to support JSON-RPC class hinting).
 
         for JSON integers (e.g. float).
 
         ``parse_constant``, if specified, will be called with one of the
-        following strings: -Infinity, Infinity, NaN, null, true, false.
+        following strings: -Infinity, Infinity, NaN.
         This can be used to raise an exception if invalid JSON numbers
         are encountered.
 
         """
         self.encoding = encoding
         self.object_hook = object_hook
-        self.parse_float = parse_float
-        self.parse_int = parse_int
-        self.parse_constant = parse_constant
+        self.parse_float = parse_float or float
+        self.parse_int = parse_int or int
+        self.parse_constant = parse_constant or _CONSTANTS.__getitem__
         self.strict = strict
+        self.parse_object = JSONObject
+        self.parse_array = JSONArray
+        self.parse_string = scanstring
+        self.scan_once = make_scanner(self)
 
     def decode(self, s, _w=WHITESPACE.match):
-        """
-        Return the Python representation of ``s`` (a ``str`` or ``unicode``
+        """Return the Python representation of ``s`` (a ``str`` or ``unicode``
         instance containing a JSON document)
 
         """
             raise ValueError(errmsg("Extra data", s, end, len(s)))
         return obj
 
-    def raw_decode(self, s, **kw):
-        """Decode a JSON document from ``s`` (a ``str`` or ``unicode`` beginning
-        with a JSON document) and return a 2-tuple of the Python
+    def raw_decode(self, s, idx=0):
+        """Decode a JSON document from ``s`` (a ``str`` or ``unicode``
+        beginning with a JSON document) and return a 2-tuple of the Python
         representation and the index in ``s`` where the document ended.
 
         This can be used to decode a JSON document from a string that may
         have extraneous data at the end.
 
         """
-        kw.setdefault('context', self)
         try:
-            obj, end = self._scanner.iterscan(s, **kw).next()
+            obj, end = self.scan_once(s, idx)
         except StopIteration:
             raise ValueError("No JSON object could be decoded")
         return obj, end

Lib/json/encoder.py

 """Implementation of JSONEncoder
 """
-
 import re
-import math
 
 try:
     from _json import encode_basestring_ascii as c_encode_basestring_ascii
 except ImportError:
     c_encode_basestring_ascii = None
-
-__all__ = ['JSONEncoder']
+try:
+    from _json import make_encoder as c_make_encoder
+except ImportError:
+    c_make_encoder = None
 
 ESCAPE = re.compile(r'[\x00-\x1f\\"\b\f\n\r\t]')
 ESCAPE_ASCII = re.compile(r'([\\"]|[^\ -~])')
 }
 for i in range(0x20):
     ESCAPE_DCT.setdefault(chr(i), '\\u{0:04x}'.format(i))
+    #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 floatstr(o, allow_nan=True):
-    # 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 math.isnan(o):
-        text = 'NaN'
-    elif math.isinf(o):
-        if math.copysign(1., o) == 1.:
-            text = 'Infinity'
-        else:
-            text = '-Infinity'
-    else:
-        return FLOAT_REPR(o)
-
-    if not allow_nan:
-        msg = "Out of range float values are not JSON compliant: " + repr(o)
-        raise ValueError(msg)
-
-    return text
-
-
 def encode_basestring(s):
     """Return a JSON representation of a Python string
 
 
 
 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):
             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)) + '"'
 
 
-if c_encode_basestring_ascii is not None:
-    encode_basestring_ascii = c_encode_basestring_ascii
-else:
-    encode_basestring_ascii = py_encode_basestring_ascii
-
+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.
     implementation (to raise ``TypeError``).
 
     """
-    __all__ = ['__init__', 'default', 'encode', 'iterencode']
     item_separator = ', '
     key_separator = ': '
     def __init__(self, skipkeys=False, ensure_ascii=True,
             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
+        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
+        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
+        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
+        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
+        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.
 
         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
-        self.current_indent_level = 0
         if separators is not None:
             self.item_separator, self.key_separator = separators
         if default is not None:
             self.default = default
         self.encoding = encoding
 
-    def _newline_indent(self):
-        return '\n' + (' ' * (self.indent * self.current_indent_level))
+    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``).
 
-    def _iterencode_list(self, lst, markers=None):
-        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
-        yield '['
-        if self.indent is not None:
-            self.current_indent_level += 1
-            newline_indent = self._newline_indent()
-            separator = self.item_separator + newline_indent
-            yield newline_indent
-        else:
-            newline_indent = None
-            separator = self.item_separator
-        first = True
-        for value in lst:
-            if first:
-                first = False
-            else:
-                yield separator
-            for chunk in self._iterencode(value, markers):
-                yield chunk
-        if newline_indent is not None:
-            self.current_indent_level -= 1
-            yield self._newline_indent()
-        yield ']'
-        if markers is not None:
-            del markers[markerid]
-
-    def _iterencode_dict(self, dct, markers=None):
-        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 '{'
-        key_separator = self.key_separator
-        if self.indent is not None:
-            self.current_indent_level += 1
-            newline_indent = self._newline_indent()
-            item_separator = self.item_separator + newline_indent
-            yield newline_indent
-        else:
-            newline_indent = None
-            item_separator = self.item_separator
-        first = True
-        if self.ensure_ascii:
-            encoder = encode_basestring_ascii
-        else:
-            encoder = encode_basestring
-        allow_nan = self.allow_nan
-        if self.sort_keys:
-            keys = dct.keys()
-            keys.sort()
-            items = [(k, dct[k]) for k in keys]
-        else:
-            items = dct.iteritems()
-        _encoding = self.encoding
-        _do_decode = (_encoding is not None
-            and not (_encoding == 'utf-8'))
-        for key, value in items:
-            if isinstance(key, str):
-                if _do_decode:
-                    key = key.decode(_encoding)
-            elif 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, allow_nan)
-            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 self.skipkeys:
-                continue
-            else:
-                raise TypeError("key {0!r} is not a string".format(key))
-            if first:
-                first = False
-            else:
-                yield item_separator
-            yield encoder(key)
-            yield key_separator
-            for chunk in self._iterencode(value, markers):
-                yield chunk
-        if newline_indent is not None:
-            self.current_indent_level -= 1
-            yield self._newline_indent()
-        yield '}'
-        if markers is not None:
-            del markers[markerid]
-
-    def _iterencode(self, o, markers=None):
-        if isinstance(o, basestring):
-            if self.ensure_ascii:
-                encoder = encode_basestring_ascii
-            else:
-                encoder = encode_basestring
-            _encoding = self.encoding
-            if (_encoding is not None and isinstance(o, str)
-                    and not (_encoding == 'utf-8')):
-                o = o.decode(_encoding)
-            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, self.allow_nan)
-        elif isinstance(o, (list, tuple)):
-            for chunk in self._iterencode_list(o, markers):
-                yield chunk
-        elif isinstance(o, dict):
-            for chunk in self._iterencode_dict(o, markers):
-                yield chunk
-        else:
-            if markers is not None:
-                markerid = id(o)
-                if markerid in markers:
-                    raise ValueError("Circular reference detected")
-                markers[markerid] = o
-            for chunk in self._iterencode_default(o, markers):
-                yield chunk
-            if markers is not None:
-                del markers[markerid]
-
-    def _iterencode_default(self, o, markers=None):
-        newobj = self.default(o)
-        return self._iterencode(newobj, markers)
-
-    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::
+        For example, to support arbitrary iterators, you could
+        implement default like this::
 
             def default(self, o):
                 try:
         # 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 = list(self.iterencode(o))
+        chunks = self.iterencode(o, _one_shot=True)
+        if not isinstance(chunks, (list, tuple)):
+            chunks = list(chunks)
         return ''.join(chunks)
 
-    def iterencode(self, o):
-        """Encode the given object and yield each string representation as
-        available.
+    def iterencode(self, o, _one_shot=False):
+        """Encode the given object and yield each string
+        representation as available.
 
         For example::
 
             markers = {}
         else:
             markers = None
-        return self._iterencode(o, markers)
+        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: " +
+                    repr(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 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)
+            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
+        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

Lib/json/scanner.py

-"""Iterator based sre token scanner
+"""JSON token scanner
+"""
+import re
+try:
+    from _json import make_scanner as c_make_scanner
+except ImportError:
+    c_make_scanner = None
 
-"""
+__all__ = ['make_scanner']
 
-import re
-import sre_parse
-import sre_compile
-import sre_constants
+NUMBER_RE = re.compile(
+    r'(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]?\d+)?',
+    (re.VERBOSE | re.MULTILINE | re.DOTALL))
 
-from re import VERBOSE, MULTILINE, DOTALL
-from sre_constants import BRANCH, SUBPATTERN
+def py_make_scanner(context):
+    parse_object = context.parse_object
+    parse_array = context.parse_array
+    parse_string = context.parse_string
+    match_number = NUMBER_RE.match
+    encoding = context.encoding
+    strict = context.strict
+    parse_float = context.parse_float
+    parse_int = context.parse_int
+    parse_constant = context.parse_constant
+    object_hook = context.object_hook
 
-__all__ = ['Scanner', 'pattern']
+    def _scan_once(string, idx):
+        try:
+            nextchar = string[idx]
+        except IndexError:
+            raise StopIteration
 
-FLAGS = (VERBOSE | MULTILINE | DOTALL)
+        if nextchar == '"':
+            return parse_string(string, idx + 1, encoding, strict)
+        elif nextchar == '{':
+            return parse_object((string, idx + 1), encoding, strict,
+                _scan_once, object_hook)
+        elif nextchar == '[':
+            return parse_array((string, idx + 1), _scan_once)
+        elif nextchar == 'n' and string[idx:idx + 4] == 'null':
+            return None, idx + 4
+        elif nextchar == 't' and string[idx:idx + 4] == 'true':
+            return True, idx + 4
+        elif nextchar == 'f' and string[idx:idx + 5] == 'false':
+            return False, idx + 5
 
-class Scanner(object):
-    def __init__(self, lexicon, flags=FLAGS):
-        self.actions = [None]
-        # Combine phrases into a compound pattern
-        s = sre_parse.Pattern()
-        s.flags = flags
-        p = []
-        for idx, token in enumerate(lexicon):
-            phrase = token.pattern
-            try:
-                subpattern = sre_parse.SubPattern(s,
-                    [(SUBPATTERN, (idx + 1, sre_parse.parse(phrase, flags)))])
-            except sre_constants.error:
-                raise
-            p.append(subpattern)
-            self.actions.append(token)
+        m = match_number(string, idx)
+        if m is not None:
+            integer, frac, exp = m.groups()
+            if frac or exp:
+                res = parse_float(integer + (frac or '') + (exp or ''))
+            else:
+                res = parse_int(integer)
+            return res, m.end()
+        elif nextchar == 'N' and string[idx:idx + 3] == 'NaN':
+            return parse_constant('NaN'), idx + 3
+        elif nextchar == 'I' and string[idx:idx + 8] == 'Infinity':
+            return parse_constant('Infinity'), idx + 8
+        elif nextchar == '-' and string[idx:idx + 9] == '-Infinity':
+            return parse_constant('-Infinity'), idx + 9
+        else:
+            raise StopIteration
 
-        s.groups = len(p) + 1 # NOTE(guido): Added to make SRE validation work
-        p = sre_parse.SubPattern(s, [(BRANCH, (None, p))])
-        self.scanner = sre_compile.compile(p)
+    return _scan_once
 
-    def iterscan(self, string, idx=0, context=None):
-        """Yield match, end_idx for each match
-
-        """
-        match = self.scanner.scanner(string, idx).match
-        actions = self.actions
-        lastend = idx
-        end = len(string)
-        while True:
-            m = match()
-            if m is None:
-                break
-            matchbegin, matchend = m.span()
-            if lastend == matchend:
-                break
-            action = actions[m.lastindex]
-            if action is not None:
-                rval, next_pos = action(m, context)
-                if next_pos is not None and next_pos != matchend:
-                    # "fast forward" the scanner
-                    matchend = next_pos
-                    match = self.scanner.scanner(string, matchend).match
-                yield rval, matchend
-            lastend = matchend
-
-
-def pattern(pattern, flags=FLAGS):
-    def decorator(fn):
-        fn.pattern = pattern
-        fn.regex = re.compile(pattern, flags)
-        return fn
-    return decorator
+make_scanner = c_make_scanner or py_make_scanner

Lib/json/tests/test_check_circular.py

+from unittest import TestCase
+import json
+
+def default_iterable(obj):
+    return list(obj)
+
+class TestCheckCircular(TestCase):
+    def test_circular_dict(self):
+        dct = {}
+        dct['a'] = dct
+        self.assertRaises(ValueError, json.dumps, dct)
+
+    def test_circular_list(self):
+        lst = []
+        lst.append(lst)
+        self.assertRaises(ValueError, json.dumps, lst)
+
+    def test_circular_composite(self):
+        dct2 = {}
+        dct2['a'] = []
+        dct2['a'].append(dct2)
+        self.assertRaises(ValueError, json.dumps, dct2)
+
+    def test_circular_default(self):
+        json.dumps([set()], default=default_iterable)
+        self.assertRaises(TypeError, json.dumps, [set()])
+
+    def test_circular_off_default(self):
+        json.dumps([set()], default=default_iterable, check_circular=False)
+        self.assertRaises(TypeError, json.dumps, [set()], check_circular=False)

Lib/json/tests/test_decode.py

         rval = json.loads('1', parse_int=float)
         self.assert_(isinstance(rval, float))
         self.assertEquals(rval, 1.0)
+
+    def test_decoder_optimizations(self):
+        # Several optimizations were made that skip over calls to
+        # the whitespace regex, so this test is designed to try and
+        # exercise the uncommon cases. The array cases are already covered.
+        rval = json.loads('{   "key"    :    "value"    ,  "k":"v"    }')
+        self.assertEquals(rval, {"key":"value", "k":"v"})

Lib/json/tests/test_dump.py

 
     def test_dumps(self):
         self.assertEquals(json.dumps({}), '{}')
+
+    def test_encode_truefalse(self):
+        self.assertEquals(json.dumps(
+                 {True: False, False: True}, sort_keys=True),
+                 '{"false": true, "true": false}')
+        self.assertEquals(json.dumps(
+                {2: 3.0, 4.0: 5L, False: 1, 6L: True, "7": 0}, sort_keys=True),
+                '{"false": 1, "2": 3.0, "4.0": 5, "6": true, "7": 0}')

Lib/json/tests/test_encode_basestring_ascii.py

         self._test_encode_basestring_ascii(json.encoder.py_encode_basestring_ascii)
 
     def test_c_encode_basestring_ascii(self):
+        if not json.encoder.c_encode_basestring_ascii:
+            return
         self._test_encode_basestring_ascii(json.encoder.c_encode_basestring_ascii)
 
     def _test_encode_basestring_ascii(self, encode_basestring_ascii):
         fname = encode_basestring_ascii.__name__
         for input_string, expect in CASES:
             result = encode_basestring_ascii(input_string)
-            self.assertEquals(result, expect)
+            self.assertEquals(result, expect,
+                '{0!r} != {1!r} for {2}({3!r})'.format(
+                    result, expect, fname, input_string))

Lib/json/tests/test_fail.py

             except ValueError:
                 pass
             else:
-                self.fail("Expected failure for fail%d.json: %r" % (idx, doc))
+                self.fail("Expected failure for fail{0}.json: {1!r}".format(idx, doc))

Lib/json/tests/test_float.py

 
 class TestFloat(TestCase):
     def test_floats(self):
-        for num in [1617161771.7650001, math.pi, math.pi**100, math.pi**-100]:
+        for num in [1617161771.7650001, math.pi, math.pi**100, math.pi**-100, 3.1]:
             self.assertEquals(float(json.dumps(num)), num)
+            self.assertEquals(json.loads(json.dumps(num)), num)
+
+    def test_ints(self):
+        for num in [1, 1L, 1<<32, 1<<64]:
+            self.assertEquals(json.dumps(num), str(num))
+            self.assertEquals(int(json.dumps(num)), num)

Lib/json/tests/test_unicode.py

     def test_unicode_decode(self):
         for i in range(0, 0xd7ff):
             u = unichr(i)
-            js = '"\\u{0:04x}"'.format(i)
-            self.assertEquals(json.loads(js), u)
+            s = '"\\u{0:04x}"'.format(i)
+            self.assertEquals(json.loads(s), u)
+
+    def test_default_encoding(self):
+        self.assertEquals(json.loads(u'{"a": "\xe9"}'.encode('utf-8')),
+            {'a': u'\xe9'})
+
+    def test_unicode_preservation(self):
+        self.assertEquals(type(json.loads(u'""')), unicode)
+        self.assertEquals(type(json.loads(u'"a"')), unicode)
+        self.assertEquals(type(json.loads(u'["a"]')[0]), unicode)
 
 Usage::
 
-    $ echo '{"json":"obj"}' | python -mjson.tool
+    $ echo '{"json":"obj"}' | python -m json.tool
     {
         "json": "obj"
     }
-    $ echo '{ 1.2:3.4}' | python -mjson.tool
+    $ echo '{ 1.2:3.4}' | python -m json.tool
     Expecting property name: line 1 column 2 (char 2)
 
 """
         infile = open(sys.argv[1], 'rb')
         outfile = open(sys.argv[2], 'wb')
     else:
-        raise SystemExit("{0} [infile [outfile]]".format(sys.argv[0]))
+        raise SystemExit(sys.argv[0] + " [infile [outfile]]")
     try:
         obj = json.load(infile)
     except ValueError, e:
 #include "Python.h"
+#include "structmember.h"
+#if PY_VERSION_HEX < 0x02060000 && !defined(Py_TYPE)
+#define Py_TYPE(ob)     (((PyObject*)(ob))->ob_type)
+#endif
+#if PY_VERSION_HEX < 0x02050000 && !defined(PY_SSIZE_T_MIN)
+typedef int Py_ssize_t;
+#define PY_SSIZE_T_MAX INT_MAX
+#define PY_SSIZE_T_MIN INT_MIN
+#define PyInt_FromSsize_t PyInt_FromLong
+#define PyInt_AsSsize_t PyInt_AsLong
+#endif
+#ifndef Py_IS_FINITE
+#define Py_IS_FINITE(X) (!Py_IS_INFINITY(X) && !Py_IS_NAN(X))
+#endif
+
+#ifdef __GNUC__
+#define UNUSED __attribute__((__unused__))
+#else
+#define UNUSED
+#endif
 
 #define DEFAULT_ENCODING "utf-8"
+
+#define PyScanner_Check(op) PyObject_TypeCheck(op, &PyScannerType)
+#define PyScanner_CheckExact(op) (Py_TYPE(op) == &PyScannerType)
+#define PyEncoder_Check(op) PyObject_TypeCheck(op, &PyEncoderType)
+#define PyEncoder_CheckExact(op) (Py_TYPE(op) == &PyEncoderType)
+
+static PyTypeObject PyScannerType;
+static PyTypeObject PyEncoderType;
+
+typedef struct _PyScannerObject {
+    PyObject_HEAD
+    PyObject *encoding;
+    PyObject *strict;
+    PyObject *object_hook;
+    PyObject *parse_float;
+    PyObject *parse_int;
+    PyObject *parse_constant;
+} PyScannerObject;
+
+static PyMemberDef scanner_members[] = {
+    {"encoding", T_OBJECT, offsetof(PyScannerObject, encoding), READONLY, "encoding"},
+    {"strict", T_OBJECT, offsetof(PyScannerObject, strict), READONLY, "strict"},
+    {"object_hook", T_OBJECT, offsetof(PyScannerObject, object_hook), READONLY, "object_hook"},
+    {"parse_float", T_OBJECT, offsetof(PyScannerObject, parse_float), READONLY, "parse_float"},
+    {"parse_int", T_OBJECT, offsetof(PyScannerObject, parse_int), READONLY, "parse_int"},
+    {"parse_constant", T_OBJECT, offsetof(PyScannerObject, parse_constant), READONLY, "parse_constant"},
+    {NULL}
+};
+
+typedef struct _PyEncoderObject {
+    PyObject_HEAD
+    PyObject *markers;
+    PyObject *defaultfn;
+    PyObject *encoder;
+    PyObject *indent;
+    PyObject *key_separator;
+    PyObject *item_separator;
+    PyObject *sort_keys;
+    PyObject *skipkeys;
+    int fast_encode;
+    int allow_nan;
+} PyEncoderObject;
+
+static PyMemberDef encoder_members[] = {
+    {"markers", T_OBJECT, offsetof(PyEncoderObject, markers), READONLY, "markers"},
+    {"default", T_OBJECT, offsetof(PyEncoderObject, defaultfn), READONLY, "default"},
+    {"encoder", T_OBJECT, offsetof(PyEncoderObject, encoder), READONLY, "encoder"},
+    {"indent", T_OBJECT, offsetof(PyEncoderObject, indent), READONLY, "indent"},
+    {"key_separator", T_OBJECT, offsetof(PyEncoderObject, key_separator), READONLY, "key_separator"},
+    {"item_separator", T_OBJECT, offsetof(PyEncoderObject, item_separator), READONLY, "item_separator"},
+    {"sort_keys", T_OBJECT, offsetof(PyEncoderObject, sort_keys), READONLY, "sort_keys"},
+    {"skipkeys", T_OBJECT, offsetof(PyEncoderObject, skipkeys), READONLY, "skipkeys"},
+    {NULL}
+};
+
+static Py_ssize_t
+ascii_escape_char(Py_UNICODE c, char *output, Py_ssize_t chars);
+static PyObject *
+ascii_escape_unicode(PyObject *pystr);
+static PyObject *
+ascii_escape_str(PyObject *pystr);
+static PyObject *
+py_encode_basestring_ascii(PyObject* self UNUSED, PyObject *pystr);
+void init_json(void);
+static PyObject *
+scan_once_str(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr);
+static PyObject *
+scan_once_unicode(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ssize_t *next_idx_ptr);
+static PyObject *
+_build_rval_index_tuple(PyObject *rval, Py_ssize_t idx);
+static PyObject *
+scanner_new(PyTypeObject *type, PyObject *args, PyObject *kwds);
+static int
+scanner_init(PyObject *self, PyObject *args, PyObject *kwds);
+static void
+scanner_dealloc(PyObject *self);
+static int
+scanner_clear(PyObject *self);
+static PyObject *
+encoder_new(PyTypeObject *type, PyObject *args, PyObject *kwds);
+static int
+encoder_init(PyObject *self, PyObject *args, PyObject *kwds);
+static void
+encoder_dealloc(PyObject *self);
+static int
+encoder_clear(PyObject *self);
+static int
+encoder_listencode_list(PyEncoderObject *s, PyObject *rval, PyObject *seq, Py_ssize_t indent_level);
+static int
+encoder_listencode_obj(PyEncoderObject *s, PyObject *rval, PyObject *obj, Py_ssize_t indent_level);
+static int
+encoder_listencode_dict(PyEncoderObject *s, PyObject *rval, PyObject *dct, Py_ssize_t indent_level);
+static PyObject *
+_encoded_const(PyObject *const);
+static void
+raise_errmsg(char *msg, PyObject *s, Py_ssize_t end);
+static PyObject *
+encoder_encode_string(PyEncoderObject *s, PyObject *obj);
+static int
+_convertPyInt_AsSsize_t(PyObject *o, Py_ssize_t *size_ptr);
+static PyObject *
+_convertPyInt_FromSsize_t(Py_ssize_t *size_ptr);
+static PyObject *
+encoder_encode_float(PyEncoderObject *s, PyObject *obj);
+
 #define S_CHAR(c) (c >= ' ' && c <= '~' && c != '\\' && c != '"')
+#define IS_WHITESPACE(c) (((c) == ' ') || ((c) == '\t') || ((c) == '\n') || ((c) == '\r'))
+
 #define MIN_EXPANSION 6
-
 #ifdef Py_UNICODE_WIDE
 #define MAX_EXPANSION (2 * MIN_EXPANSION)
 #else
 #define MAX_EXPANSION MIN_EXPANSION
 #endif
 
+static int
+_convertPyInt_AsSsize_t(PyObject *o, Py_ssize_t *size_ptr)
+{
+    /* PyObject to Py_ssize_t converter */
+    *size_ptr = PyInt_AsSsize_t(o);
+    if (*size_ptr == -1 && PyErr_Occurred());
+        return 1;
+    return 0;
+}
+
+static PyObject *
+_convertPyInt_FromSsize_t(Py_ssize_t *size_ptr)
+{
+    /* Py_ssize_t to PyObject converter */
+    return PyInt_FromSsize_t(*size_ptr);
+}
+
 static Py_ssize_t
 ascii_escape_char(Py_UNICODE c, char *output, Py_ssize_t chars)
 {
-    Py_UNICODE x;
+    /* Escape unicode code point c to ASCII escape sequences
+    in char *output. output must have at least 12 bytes unused to
+    accommodate an escaped surrogate pair "\uXXXX\uXXXX" */
     output[chars++] = '\\';
     switch (c) {
         case '\\': output[chars++] = (char)c; break;
                 Py_UNICODE v = c - 0x10000;
                 c = 0xd800 | ((v >> 10) & 0x3ff);
                 output[chars++] = 'u';
-                x = (c & 0xf000) >> 12;
-                output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
-                x = (c & 0x0f00) >> 8;
-                output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
-                x = (c & 0x00f0) >> 4;
-                output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
-                x = (c & 0x000f);
-                output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
+                output[chars++] = "0123456789abcdef"[(c >> 12) & 0xf];
+                output[chars++] = "0123456789abcdef"[(c >>  8) & 0xf];
+                output[chars++] = "0123456789abcdef"[(c >>  4) & 0xf];
+                output[chars++] = "0123456789abcdef"[(c      ) & 0xf];
                 c = 0xdc00 | (v & 0x3ff);
                 output[chars++] = '\\';
             }
 #endif
             output[chars++] = 'u';
-            x = (c & 0xf000) >> 12;
-            output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
-            x = (c & 0x0f00) >> 8;
-            output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
-            x = (c & 0x00f0) >> 4;
-            output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
-            x = (c & 0x000f);
-            output[chars++] = (x < 10) ? '0' + x : 'a' + (x - 10);
+            output[chars++] = "0123456789abcdef"[(c >> 12) & 0xf];
+            output[chars++] = "0123456789abcdef"[(c >>  8) & 0xf];
+            output[chars++] = "0123456789abcdef"[(c >>  4) & 0xf];
+            output[chars++] = "0123456789abcdef"[(c      ) & 0xf];
     }
     return chars;
 }
 static PyObject *
 ascii_escape_unicode(PyObject *pystr)
 {
+    /* Take a PyUnicode pystr and return a new ASCII-only escaped PyString */
     Py_ssize_t i;
     Py_ssize_t input_chars;
     Py_ssize_t output_size;
+    Py_ssize_t max_output_size;
     Py_ssize_t chars;
     PyObject *rval;
     char *output;
 
     input_chars = PyUnicode_GET_SIZE(pystr);
     input_unicode = PyUnicode_AS_UNICODE(pystr);
+
     /* One char input can be up to 6 chars output, estimate 4 of these */
     output_size = 2 + (MIN_EXPANSION * 4) + input_chars;
+    max_output_size = 2 + (input_chars * MAX_EXPANSION);
     rval = PyString_FromStringAndSize(NULL, output_size);
     if (rval == NULL) {
         return NULL;
         if (S_CHAR(c)) {
             output[chars++] = (char)c;
         }
-	else {
+        else {
             chars = ascii_escape_char(c, output, chars);
         }
         if (output_size - chars < (1 + MAX_EXPANSION)) {
             /* There's more than four, so let's resize by a lot */
-            output_size *= 2;
+            Py_ssize_t new_output_size = output_size * 2;
             /* This is an upper bound */
-            if (output_size > 2 + (input_chars * MAX_EXPANSION)) {
-                output_size = 2 + (input_chars * MAX_EXPANSION);
+            if (new_output_size > max_output_size) {
+                new_output_size = max_output_size;
             }
-            if (_PyString_Resize(&rval, output_size) == -1) {
-                return NULL;
+            /* Make sure that the output size changed before resizing */
+            if (new_output_size != output_size) {
+                output_size = new_output_size;
+                if (_PyString_Resize(&rval, output_size) == -1) {
+                    return NULL;
+                }
+                output = PyString_AS_STRING(rval);
             }
-            output = PyString_AS_STRING(rval);
         }
     }
     output[chars++] = '"';
 static PyObject *
 ascii_escape_str(PyObject *pystr)
 {
+    /* Take a PyString pystr and return a new ASCII-only escaped PyString */
     Py_ssize_t i;
     Py_ssize_t input_chars;
     Py_ssize_t output_size;
 
     input_chars = PyString_GET_SIZE(pystr);
     input_str = PyString_AS_STRING(pystr);
-    /* One char input can be up to 6 chars output, estimate 4 of these */
-    output_size = 2 + (MIN_EXPANSION * 4) + input_chars;
+
+    /* Fast path for a string that's already ASCII */
+    for (i = 0; i < input_chars; i++) {
+        Py_UNICODE c = (Py_UNICODE)(unsigned char)input_str[i];
+        if (!S_CHAR(c)) {
+            /* If we have to escape something, scan the string for unicode */
+            Py_ssize_t j;
+            for (j = i; j < input_chars; j++) {
+                c = (Py_UNICODE)(unsigned char)input_str[j];
+                if (c > 0x7f) {
+                    /* We hit a non-ASCII character, bail to unicode mode */
+                    PyObject *uni;
+                    uni = PyUnicode_DecodeUTF8(input_str, input_chars, "strict");
+                    if (uni == NULL) {
+                        return NULL;
+                    }
+                    rval = ascii_escape_unicode(uni);
+                    Py_DECREF(uni);
+                    return rval;
+                }
+            }
+            break;
+        }
+    }
+
+    if (i == input_chars) {
+        /* Input is already ASCII */
+        output_size = 2 + input_chars;
+    }
+    else {
+        /* One char input can be up to 6 chars output, estimate 4 of these */
+        output_size = 2 + (MIN_EXPANSION * 4) + input_chars;
+    }
     rval = PyString_FromStringAndSize(NULL, output_size);
     if (rval == NULL) {
         return NULL;
     }
     output = PyString_AS_STRING(rval);
-    chars = 0;
-    output[chars++] = '"';
-    for (i = 0; i < input_chars; i++) {
-        Py_UNICODE c = (Py_UNICODE)input_str[i];
+    output[0] = '"';
+
+    /* We know that everything up to i is ASCII already */
+    chars = i + 1;
+    memcpy(&output[1], input_str, i);
+
+    for (; i < input_chars; i++) {
+        Py_UNICODE c = (Py_UNICODE)(unsigned char)input_str[i];
         if (S_CHAR(c)) {
             output[chars++] = (char)c;
         }
-	else if (c > 0x7F) {
-            /* We hit a non-ASCII character, bail to unicode mode */
-            PyObject *uni;
-            Py_DECREF(rval);
-            uni = PyUnicode_DecodeUTF8(input_str, input_chars, "strict");
-            if (uni == NULL) {
-                return NULL;
-            }
-            rval = ascii_escape_unicode(uni);
-            Py_DECREF(uni);
-            return rval;
-        }
-	else {
+        else {
             chars = ascii_escape_char(c, output, chars);
         }
         /* An ASCII char can't possibly expand to a surrogate! */
     return rval;
 }
 
-void
+static void
 raise_errmsg(char *msg, PyObject *s, Py_ssize_t end)
 {
+    /* Use the Python function json.decoder.errmsg to raise a nice
+    looking ValueError exception */
     static PyObject *errmsg_fn = NULL;
     PyObject *pymsg;
     if (errmsg_fn == NULL) {
         if (decoder == NULL)
             return;
         errmsg_fn = PyObject_GetAttrString(decoder, "errmsg");
+        Py_DECREF(decoder);
         if (errmsg_fn == NULL)
             return;
-        Py_DECREF(decoder);
     }
-    pymsg = PyObject_CallFunction(errmsg_fn, "(zOn)", msg, s, end);
+    pymsg = PyObject_CallFunction(errmsg_fn, "(zOO&)", msg, s, _convertPyInt_FromSsize_t, &end);
     if (pymsg) {
         PyErr_SetObject(PyExc_ValueError, pymsg);
         Py_DECREF(pymsg);
     }
-/*
-
-def linecol(doc, pos):
-    lineno = doc.count('\n', 0, pos) + 1
-    if lineno == 1:
-        colno = pos
-    else:
-        colno = pos - doc.rindex('\n', 0, pos)
-    return lineno, colno
-
-def errmsg(msg, doc, pos, end=None):
-    lineno, colno = linecol(doc, pos)
-    if end is None:
-        return '%s: line %d column %d (char %d)' % (msg, lineno, colno, pos)
-    endlineno, endcolno = linecol(doc, end)
-    return '%s: line %d column %d - line %d column %d (char %d - %d)' % (
-        msg, lineno, colno, endlineno, endcolno, pos, end)
-
-*/
 }
 
 static PyObject *
 join_list_unicode(PyObject *lst)
 {
-    static PyObject *ustr = NULL;
-    static PyObject *joinstr = NULL;
-    if (ustr == NULL) {
-        Py_UNICODE c = 0;
-        ustr = PyUnicode_FromUnicode(&c, 0);
+    /* return u''.join(lst) */
+    static PyObject *joinfn = NULL;
+    if (joinfn == NULL) {
+        PyObject *ustr = PyUnicode_FromUnicode(NULL, 0);
+        if (ustr == NULL)
+            return NULL;
+
+        joinfn = PyObject_GetAttrString(ustr, "join");
+        Py_DECREF(ustr);
+        if (joinfn == NULL)
+            return NULL;
     }
-    if (joinstr == NULL) {
-        joinstr = PyString_InternFromString("join");
-    }
-    if (joinstr == NULL || ustr == NULL) {
-        return NULL;
-    }
-    return PyObject_CallMethodObjArgs(ustr, joinstr, lst, NULL);
+    return PyObject_CallFunctionObjArgs(joinfn, lst, NULL);
 }
 
 static PyObject *
-scanstring_str(PyObject *pystr, Py_ssize_t end, char *encoding, int strict)
+join_list_string(PyObject *lst)
 {
+    /* return ''.join(lst) */
+    static PyObject *joinfn = NULL;
+    if (joinfn == NULL) {
+        PyObject *ustr = PyString_FromStringAndSize(NULL, 0);
+        if (ustr == NULL)
+            return NULL;
+
+        joinfn = PyObject_GetAttrString(ustr, "join");
+        Py_DECREF(ustr);
+        if (joinfn == NULL)
+            return NULL;
+    }
+    return PyObject_CallFunctionObjArgs(joinfn, lst, NULL);
+}
+
+static PyObject *
+_build_rval_index_tuple(PyObject *rval, Py_ssize_t idx) {
+    /* return (rval, idx) tuple, stealing reference to rval */
+    PyObject *tpl;
+    PyObject *pyidx;
+    /*
+    steal a reference to rval, returns (rval, idx)
+    */
+    if (rval == NULL) {
+        return NULL;
+    }
+    pyidx = PyInt_FromSsize_t(idx);
+    if (pyidx == NULL) {
+        Py_DECREF(rval);
+        return NULL;
+    }
+    tpl = PyTuple_New(2);
+    if (tpl == NULL) {
+        Py_DECREF(pyidx);
+        Py_DECREF(rval);
+        return NULL;
+    }
+    PyTuple_SET_ITEM(tpl, 0, rval);
+    PyTuple_SET_ITEM(tpl, 1, pyidx);
+    return tpl;
+}
+
+static PyObject *
+scanstring_str(PyObject *pystr, Py_ssize_t end, char *encoding, int strict, Py_ssize_t *next_end_ptr)
+{
+    /* Read the JSON string from PyString pystr.
+    end is the index of the first character after the quote.
+    encoding is the encoding of pystr (must be an ASCII superset)
+    if strict is zero then literal control characters are allowed
+    *next_end_ptr is a return-by-reference index of the character
+        after the end quote
+
+    Return value is a new PyString (if ASCII-only) or PyUnicode
+    */
     PyObject *rval;
     Py_ssize_t len = PyString_GET_SIZE(pystr);
     Py_ssize_t begin = end - 1;
     Py_ssize_t next = begin;
+    int has_unicode = 0;
     char *buf = PyString_AS_STRING(pystr);
     PyObject *chunks = PyList_New(0);
     if (chunks == NULL) {
         Py_UNICODE c = 0;
         PyObject *chunk = NULL;
         for (next = end; next < len; next++) {
-            c = buf[next];
+            c = (unsigned char)buf[next];
             if (c == '"' || c == '\\') {
                 break;
             }
                 raise_errmsg("Invalid control character at", pystr, next);
                 goto bail;
             }
+            else if (c > 0x7f) {
+                has_unicode = 1;
+            }
         }
         if (!(c == '"' || c == '\\')) {
             raise_errmsg("Unterminated string starting at", pystr, begin);
         }
         /* Pick up this chunk if it's not zero length */
         if (next != end) {
-            PyObject *strchunk = PyBuffer_FromMemory(&buf[end], next - end);
+            PyObject *strchunk = PyString_FromStringAndSize(&buf[end], next - end);
             if (strchunk == NULL) {
                 goto bail;
             }
-            chunk = PyUnicode_FromEncodedObject(strchunk, encoding, NULL);
-            Py_DECREF(strchunk);
-            if (chunk == NULL) {
-                goto bail;
+            if (has_unicode) {
+                chunk = PyUnicode_FromEncodedObject(strchunk, encoding, NULL);
+                Py_DECREF(strchunk);
+                if (chunk == NULL) {
+                    goto bail;
+                }
+            }
+            else {
+                chunk = strchunk;
             }
             if (PyList_Append(chunks, chunk)) {
                 Py_DECREF(chunk);
             }
             /* Decode 4 hex digits */
             for (; next < end; next++) {
-                Py_ssize_t shl = (end - next - 1) << 2;
                 Py_UNICODE digit = buf[next];
+                c <<= 4;
                 switch (digit) {
                     case '0': case '1': case '2': case '3': case '4':
                     case '5': case '6': case '7': case '8': case '9':
-                        c |= (digit - '0') << shl; break;
+                        c |= (digit - '0'); break;
                     case 'a': case 'b': case 'c': case 'd': case 'e':
                     case 'f':
-                        c |= (digit - 'a' + 10) << shl; break;
+                        c |= (digit - 'a' + 10); break;
                     case 'A': case 'B': case 'C': case 'D': case 'E':
                     case 'F':
-                        c |= (digit - 'A' + 10) << shl; break;
+                        c |= (digit - 'A' + 10); break;
                     default:
                         raise_errmsg("Invalid \\uXXXX escape", pystr, end - 5);
                         goto bail;
             }
 #ifdef Py_UNICODE_WIDE
             /* Surrogate pair */
-            if (c >= 0xd800 && c <= 0xdbff) {
+            if ((c & 0xfc00) == 0xd800) {
                 Py_UNICODE c2 = 0;
                 if (end + 6 >= len) {
-                    raise_errmsg("Invalid \\uXXXX\\uXXXX surrogate pair", pystr,
-                        end - 5);
+                    raise_errmsg("Unpaired high surrogate", pystr, end - 5);
+                    goto bail;
                 }
                 if (buf[next++] != '\\' || buf[next++] != 'u') {
-                    raise_errmsg("Invalid \\uXXXX\\uXXXX surrogate pair", pystr,
-                        end - 5);
+                    raise_errmsg("Unpaired high surrogate", pystr, end - 5);
+                    goto bail;
                 }
                 end += 6;
                 /* Decode 4 hex digits */
                 for (; next < end; next++) {
-                    Py_ssize_t shl = (end - next - 1) << 2;
+                    c2 <<= 4;
                     Py_UNICODE digit = buf[next];
                     switch (digit) {
                         case '0': case '1': case '2': case '3': case '4':
                         case '5': case '6': case '7': case '8': case '9':
-                            c2 |= (digit - '0') << shl; break;
+                            c2 |= (digit - '0'); break;
                         case 'a': case 'b': case 'c': case 'd': case 'e':
                         case 'f':
-                            c2 |= (digit - 'a' + 10) << shl; break;
+                            c2 |= (digit - 'a' + 10); break;
                         case 'A': case 'B': case 'C': case 'D': case 'E':
                         case 'F':
-                            c2 |= (digit - 'A' + 10) << shl; break;
+                            c2 |= (digit - 'A' + 10); break;
                         default:
                             raise_errmsg("Invalid \\uXXXX escape", pystr, end - 5);
                             goto bail;
                     }
                 }
+                if ((c2 & 0xfc00) != 0xdc00) {
+                    raise_errmsg("Unpaired high surrogate", pystr, end - 5);
+                    goto bail;
+                }
                 c = 0x10000 + (((c - 0xd800) << 10) | (c2 - 0xdc00));
             }
+            else if ((c & 0xfc00) == 0xdc00) {
+                raise_errmsg("Unpaired low surrogate", pystr, end - 5);
+                goto bail;
+            }
 #endif
         }
-        chunk = PyUnicode_FromUnicode(&c, 1);
-        if (chunk == NULL) {
-            goto bail;
+        if (c > 0x7f) {
+            has_unicode = 1;
+        }
+        if (has_unicode) {
+            chunk = PyUnicode_FromUnicode(&c, 1);
+            if (chunk == NULL) {
+                goto bail;
+            }
+        }
+        else {
+            char c_char = Py_CHARMASK(c);
+            chunk = PyString_FromStringAndSize(&c_char, 1);
+            if (chunk == NULL) {
+                goto bail;
+            }
         }
         if (PyList_Append(chunks, chunk)) {
             Py_DECREF(chunk);
         Py_DECREF(chunk);
     }
 
-    rval = join_list_unicode(chunks);
+    rval = join_list_string(chunks);
     if (rval == NULL) {
         goto bail;
     }
     Py_CLEAR(chunks);
-    return Py_BuildValue("(Nn)", rval, end);
+    *next_end_ptr = end;
+    return rval;
 bail:
+    *next_end_ptr = -1;
     Py_XDECREF(chunks);
     return NULL;
 }
 
 
 static PyObject *
-scanstring_unicode(PyObject *pystr, Py_ssize_t end, int strict)
+scanstring_unicode(PyObject *pystr, Py_ssize_t end, int strict, Py_ssize_t *next_end_ptr)
 {
+    /* Read the JSON string from PyUnicode pystr.
+    end is the index of the first character after the quote.