1 files changed, 275 insertions, 0 deletions
diff --git a/simple_json/encoder.py b/simple_json/encoder.py
new file mode 100644
index 0000000..71dfdb4
--- /dev/null
+++ b/simple_json/encoder.py
@@ -0,0 +1,275 @@
+"""
+Implementation of JSONEncoder
+"""
+import re
+import math
+
+# this should match any kind of infinity
+INFCHARS = re.compile(r'[infINF]')
+ESCAPE = re.compile(r'[\x00-\x19\\"\b\f\n\r\t]')
+ESCAPE_ASCII = re.compile(r'([\\"]|[^\ -~])')
+ESCAPE_DCT = {
+    '\\': '\\\\',
+    '"': '\\"',
+    '\b': '\\b',
+    '\f': '\\f',
+    '\n': '\\n',
+    '\r': '\\r',
+    '\t': '\\t',
+}
+for i in range(20):
+    ESCAPE_DCT.setdefault(chr(i), '\\u%04x' % (i,))
+
+def floatstr(o, allow_nan=True):
+    s = str(o)
+    # If the first non-sign is a digit then it's not a special value
+    if (o < 0.0 and s[1].isdigit()) or s[0].isdigit():
+        return s
+    elif not allow_nan:
+        raise ValueError("Out of range float values are not JSON compliant: %r"
+            % (o,))
+    # These are the string representations on the platforms I've tried
+    if s == 'nan':
+        return 'NaN'
+    if s == 'inf':
+        return 'Infinity'
+    if s == '-inf':
+        return '-Infinity'
+    # NaN should either be inequal to itself, or equal to everything
+    if o != o or o == 0.0:
+        return 'NaN'
+    # Last ditch effort, assume inf
+    if o < 0:
+        return '-Infinity'
+    return 'Infinity'
+
+def encode_basestring(s):
+    """
+    Return a JSON representation of a Python string
+    """
+    def replace(match):
+        return ESCAPE_DCT[match.group(0)]
+    return '"' + ESCAPE.sub(replace, s) + '"'
+
+def encode_basestring_ascii(s):
+    def replace(match):
+        s = match.group(0)
+        try:
+            return ESCAPE_DCT[s]
+        except KeyError:
+            return '\\u%04x' % (ord(s),)
+    return '"' + str(ESCAPE_ASCII.sub(replace, s)) + '"'
+        
+
+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(o)`` method with another method that returns a serializable
+    object for ``o`` if possible, otherwise it should call the superclass
+    implementation (to raise ``TypeError``).
+    """
+    def __init__(self, skipkeys=False, ensure_ascii=True, check_circular=True,
+            allow_nan=True):
+        """
+        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.
+        """
+        
+        self.skipkeys = skipkeys
+        self.ensure_ascii = ensure_ascii
+        self.check_circular = check_circular
+        self.allow_nan = allow_nan
+
+    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 '['
+        first = True
+        for value in lst:
+            if first:
+                first = False
+            else:
+                yield ', '
+            for chunk in self._iterencode(value, markers):
+                yield chunk
+        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 '{'
+        first = True
+        if self.ensure_ascii:
+            encoder = encode_basestring_ascii
+        else:
+            encoder = encode_basestring
+        allow_nan = self.allow_nan
+        for key, value in dct.iteritems():
+            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, 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 %r is not a string" % (key,))
+            if first:
+                first = False
+            else:
+                yield ', '
+            yield encoder(key)
+            yield ':'
+            for chunk in self._iterencode(value, markers):
+                yield chunk
+        yield '}'
+        if markers is not None:
+            del markers[markerid]
+
+    def iterencode(self, o):
+        """
+        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
+        return self._iterencode(o, markers)
+
+    def _iterencode(self, o, markers=None):
+        if isinstance(o, basestring):
+            if self.ensure_ascii:
+                encoder = encode_basestring_ascii
+            else:
+                encoder = encode_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, 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::
+            
+            def default(self, o):
+                try:
+                    iterable = iter(o)
+                except TypeError:
+                    pass
+                else:
+                    return list(iterable)
+                return JSONEncoder.default(self, o)
+        """
+        raise TypeError("%r is not JSON serializable" % (o,))
+
+    def encode(self, o):
+        """
+        Return a JSON string representation of a Python data structure.
+        """
+        # This doesn't pass the iterator directly to ''.join() because it
+        # sucks at reporting exceptions.  It's going to do this internally
+        # anyway because it uses PySequence_Fast or similar.
+        chunks = list(self.iterencode(o))
+        return ''.join(chunks)
+
+__all__ = ['JSONEncoder']