Author: Antonio Cuni <[email protected]>
Branch: fastjson
Changeset: r64792:535479329816
Date: 2013-06-05 14:14 +0200
http://bitbucket.org/pypy/pypy/changeset/535479329816/
Log: add support for parsing float values
diff --git a/pypy/module/_fastjson/interp_decoder.py
b/pypy/module/_fastjson/interp_decoder.py
--- a/pypy/module/_fastjson/interp_decoder.py
+++ b/pypy/module/_fastjson/interp_decoder.py
@@ -7,6 +7,15 @@
def is_whitespace(ch):
return ch == ' ' or ch == '\t' or ch == '\r' or ch == '\n'
+# precomputing negative powers of 10 is MUCH faster than using e.g. math.pow
+# at runtime
+NEG_POW_10 = [10**-i for i in range(16)]
+def neg_pow_10(x, exp):
+ if exp >= len(NEG_POW_10):
+ return 0.0
+ return x * NEG_POW_10[exp]
+
+
TYPE_UNKNOWN = 0
TYPE_STRING = 1
@@ -23,6 +32,12 @@
def peek(self):
return self.s[self.i]
+ def peek_maybe(self):
+ if self.eof():
+ return '\0'
+ else:
+ return self.peek()
+
def next(self):
ch = self.peek()
self.i += 1
@@ -56,30 +71,69 @@
self.next()
return self.decode_string()
elif ch.isdigit() or ch == '-':
- return self.decode_numeric(ch)
+ return self.decode_numeric()
elif ch == '{':
self.next()
return self.decode_object()
else:
- assert False, 'Unkown char: %s' % ch
+ self._raise("No JSON object could be decoded: unexpected '%s' at
char %d",
+ ch, self.i)
- def decode_numeric(self, ch):
- intval = 0
+ def decode_numeric(self):
+ intval = self.parse_integer()
+ #
+ is_float = False
+ exp = 0
+ frcval = 0.0
+ frccount = 0
+ #
+ # check for the optional fractional part
+ ch = self.peek_maybe()
+ if ch == '.':
+ is_float = True
+ self.next()
+ frcval, frccount = self.parse_digits()
+ frcval = neg_pow_10(frcval, frccount)
+ ch = self.peek_maybe()
+ # check for the optional exponent part
+ if ch == 'E' or ch == 'e':
+ is_float = True
+ self.next()
+ exp = self.parse_integer()
+ #
+ if is_float:
+ # build the float
+ floatval = intval + frcval
+ floatval = floatval * 10**exp
+ return self.space.wrap(floatval)
+ else:
+ return self.space.wrap(intval)
+
+ def parse_integer(self):
+ "Parse a decimal number with an optional minus sign"
sign = 1
- if ch == '-':
+ if self.peek_maybe() == '-':
sign = -1
self.next()
+ intval, _ = self.parse_digits()
+ return sign * intval
+ def parse_digits(self):
+ "Parse a sequence of digits as a decimal number. No sign allowed"
+ intval = 0
+ count = 0
while not self.eof():
ch = self.peek()
if ch.isdigit():
intval = intval*10 + ord(ch)-ord('0')
+ count += 1
self.next()
else:
break
- #
- intval = intval*sign
- return self.space.wrap(intval)
+ if count == 0:
+ self._raise("Expected digit at char %d", self.i)
+ return intval, count
+
def decode_object(self):
start = self.i
diff --git a/pypy/module/_fastjson/test/test__fastjson.py
b/pypy/module/_fastjson/test/test__fastjson.py
--- a/pypy/module/_fastjson/test/test__fastjson.py
+++ b/pypy/module/_fastjson/test/test__fastjson.py
@@ -71,9 +71,31 @@
def test_decode_numeric(self):
import _fastjson
- assert _fastjson.loads('42') == 42
- assert _fastjson.loads('-42') == -42
- raises(ValueError, "_fastjson.loads('42 abc')")
+ def check(s, val):
+ res = _fastjson.loads(s)
+ assert type(res) is type(val)
+ assert res == val
+ #
+ check('42', 42)
+ check('-42', -42)
+ check('42.123', 42.123)
+ check('42E0', 42.0)
+ check('42E3', 42000.0)
+ check('42E-1', 4.2)
+ check('42.123E3', 42123.0)
+
+ def test_decode_numeric_invalid(self):
+ import _fastjson
+ def error(s):
+ raises(ValueError, _fastjson.loads, s)
+ #
+ error(' 42 abc')
+ error('.123')
+ error('12.')
+ error('12.-3')
+ error('12E')
+ error('12E-')
+
def test_decode_object(self):
import _fastjson
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