Index: Lib/json/decoder.py
===================================================================
--- Lib/json/decoder.py	(revision 66961)
+++ Lib/json/decoder.py	(working copy)
@@ -3,8 +3,9 @@
 
 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:
@@ -40,36 +41,8 @@
     '-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'/',
@@ -100,7 +73,7 @@
             break
         elif terminator != '\\':
             if strict:
-                msg = "Invalid control character {0!r} at".format(terminator)
+                msg = "Invalid control character {0!r} at".format(esc)
                 raise ValueError(errmsg(msg, s, end))
             else:
                 _append(terminator)
@@ -114,8 +87,8 @@
             try:
                 m = _b[esc]
             except KeyError:
-                msg = "Invalid \\escape: {0!r}".format(esc)
-                raise ValueError(errmsg(msg, s, end))
+                raise ValueError(
+                    errmsg("Invalid \\escape: {0!r}".format(esc), s, end))
             end += 1
         else:
             esc = s[end + 1:end + 5]
@@ -143,104 +116,121 @@
     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()
     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()
-    # Look-ahead for trivial empty array
     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
     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()
-    return values, end
-pattern(r'\[')(JSONArray)
 
+        try:
+            if s[end] in _ws:
+                end += 1
+                if s[end] in _ws:
+                    end = _w(s, end + 1).end()
+        except IndexError:
+            pass
 
-ANYTHING = [
-    JSONObject,
-    JSONArray,
-    JSONString,
-    JSONConstant,
-    JSONNumber,
-]
+    return values, end
 
-JSONScanner = Scanner(ANYTHING)
-
-
 class JSONDecoder(object):
     """Simple JSON <http://json.org> decoder
 
@@ -270,7 +260,6 @@
     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,
@@ -282,8 +271,8 @@
         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).
 
@@ -298,21 +287,24 @@
         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)
 
         """
@@ -322,7 +314,7 @@
             raise ValueError(errmsg("Extra data", s, end, len(s)))
         return obj
 
-    def raw_decode(self, s, **kw):
+    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.
@@ -331,9 +323,8 @@
         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