1 files changed, 56 insertions, 59 deletions
diff --git a/Lib/json/scanner.py b/Lib/json/scanner.py
index 4b065ab..00c5470 100644
--- a/Lib/json/scanner.py
+++ b/Lib/json/scanner.py
@@ -1,69 +1,66 @@
-"""Iterator based sre token scanner
-
+"""JSON token scanner
 """
-
 import re
-import sre_parse
-import sre_compile
-import sre_constants
-
-from re import VERBOSE, MULTILINE, DOTALL
-from sre_constants import BRANCH, SUBPATTERN
+try:
+    from _json import make_scanner as c_make_scanner
+except ImportError:
+    c_make_scanner = None
 
-__all__ = ['Scanner', 'pattern']
+__all__ = ['make_scanner']
 
-FLAGS = (VERBOSE | MULTILINE | DOTALL)
+NUMBER_RE = re.compile(
+    r'(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]?\d+)?',
+    (re.VERBOSE | re.MULTILINE | re.DOTALL))
 
-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)
+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
 
-        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)
+    def _scan_once(string, idx):
+        try:
+            nextchar = string[idx]
+        except IndexError:
+            raise StopIteration
 
-    def iterscan(self, string, idx=0, context=None):
-        """Yield match, end_idx for each match
+        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
 
-        """
-        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
+        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
 
+    return _scan_once
 
-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