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"""Implementation of HjsonDecoder
"""
from __future__ import absolute_import
import re
import sys
import struct
from .compat import fromhex, b, u, text_type, binary_type, PY3, unichr
from .scanner import HjsonDecodeError
# NOTE (3.1.0): HjsonDecodeError may still be imported from this module for
# compatibility, but it was never in the __all__
__all__ = ['HjsonDecoder']
FLAGS = re.VERBOSE | re.MULTILINE | re.DOTALL
def _floatconstants():
_BYTES = fromhex('7FF80000000000007FF0000000000000')
# The struct module in Python 2.4 would get frexp() out of range here
# when an endian is specified in the format string. Fixed in Python 2.5+
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()
WHITESPACE = ' \t\n\r'
PUNCTUATOR = '{}[],:'
NUMBER_RE = re.compile(r'[\t ]*(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]?\d+)?[\t ]*')
STRINGCHUNK = re.compile(r'(.*?)([\'"\\\x00-\x1f])', FLAGS)
BACKSLASH = {
'"': u('"'), '\'': u('\''), '\\': u('\u005c'), '/': u('/'),
'b': u('\b'), 'f': u('\f'), 'n': u('\n'), 'r': u('\r'), 't': u('\t'),
}
DEFAULT_ENCODING = "utf-8"
def getNext(s, end):
while 1:
# Use a slice to prevent IndexError from being raised
ch = s[end:end + 1]
# Skip whitespace.
while ch in WHITESPACE:
if ch == '': return ch, end
end += 1
ch = s[end:end + 1]
# Hjson allows comments
ch2 = s[end + 1:end + 2]
if ch == '#' or ch == '/' and ch2 == '/':
end = getEol(s, end)
elif ch == '/' and ch2 == '*':
end += 2
ch = s[end]
while ch != '' and not (ch == '*' and s[end + 1] == '/'):
end += 1
ch = s[end]
if ch != '':
end += 2
else:
break
return ch, end
def getEol(s, end):
# skip until eol
while 1:
ch = s[end:end + 1]
if ch == '\r' or ch == '\n' or ch == '':
return end
end += 1
def skipIndent(s, end, n):
ch = s[end:end + 1]
while ch != '' and ch in " \t\r" and (n > 0 or n < 0):
end += 1
n -= 1
ch = s[end:end + 1]
return end
def scanstring(s, end, encoding=None, strict=True,
_b=BACKSLASH, _m=STRINGCHUNK.match, _join=u('').join,
_PY3=PY3, _maxunicode=sys.maxunicode):
"""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.
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 = []
_append = chunks.append
begin = end - 1
# callers make sure that string starts with " or '
exitCh = s[begin]
while 1:
chunk = _m(s, end)
if chunk is None:
raise HjsonDecodeError(
"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 _PY3 and not isinstance(content, text_type):
content = text_type(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 == exitCh:
break
elif terminator == '"' or terminator == '\'':
_append(terminator)
continue
elif terminator != '\\':
if strict:
msg = "Invalid control character %r at"
raise HjsonDecodeError(msg, s, end)
else:
_append(terminator)
continue
try:
esc = s[end]
except IndexError:
raise HjsonDecodeError(
"Unterminated string starting at", s, begin)
# If not a unicode escape sequence, must be in the lookup table
if esc != 'u':
try:
char = _b[esc]
except KeyError:
msg = "Invalid \\X escape sequence %r"
raise HjsonDecodeError(msg, s, end)
end += 1
else:
# Unicode escape sequence
msg = "Invalid \\uXXXX escape sequence"
esc = s[end + 1:end + 5]
escX = esc[1:2]
if len(esc) != 4 or escX == 'x' or escX == 'X':
raise HjsonDecodeError(msg, s, end - 1)
try:
uni = int(esc, 16)
except ValueError:
raise HjsonDecodeError(msg, s, end - 1)
end += 5
# Check for surrogate pair on UCS-4 systems
# Note that this will join high/low surrogate pairs
# but will also pass unpaired surrogates through
if (_maxunicode > 65535 and
uni & 0xfc00 == 0xd800 and
s[end:end + 2] == '\\u'):
esc2 = s[end + 2:end + 6]
escX = esc2[1:2]
if len(esc2) == 4 and not (escX == 'x' or escX == 'X'):
try:
uni2 = int(esc2, 16)
except ValueError:
raise HjsonDecodeError(msg, s, end)
if uni2 & 0xfc00 == 0xdc00:
uni = 0x10000 + (((uni - 0xd800) << 10) |
(uni2 - 0xdc00))
end += 6
char = unichr(uni)
# Append the unescaped character
_append(char)
return _join(chunks), end
def mlscanstring(s, end):
"""Scan a multiline string"""
string = ""
triple = 0
# we are at ''' - get indent
indent = 0
while 1:
ch = s[end-indent-1]
if ch == '\n': break
indent += 1
# skip white/to (newline)
end = skipIndent(s, end + 3, -1)
ch = s[end]
if ch == '\n': end = skipIndent(s, end + 1, indent)
# When parsing multiline string values, we must look for ' characters
while 1:
ch = s[end:end + 1]
if ch == '':
raise HjsonDecodeError("Bad multiline string", s, end);
elif ch == '\'':
triple += 1
end += 1
if triple == 3:
if string and string[-1] == '\n':
string = string[:-1] # remove last EOL
return string, end
else:
continue
else:
while triple > 0:
string += '\''
triple -= 1
if ch == '\n':
string += ch
end = skipIndent(s, end + 1, indent)
else:
if ch != '\r':
string += ch
end += 1
def scantfnns(context, s, end):
"""Scan s until eol. return string, True, False or None"""
chf, begin = getNext(s, end)
end = begin
if chf in PUNCTUATOR:
raise HjsonDecodeError("Found a punctuator character when expecting a quoteless string (check your syntax)", s, end);
while 1:
ch = s[end:end + 1]
isEol = ch == '\r' or ch == '\n' or ch == ''
if isEol or ch == ',' or \
ch == '}' or ch == ']' or \
ch == '#' or \
ch == '/' and (s[end + 1:end + 2] == '/' or s[end + 1:end + 2] == '*'):
m = None
mend = end
if next: mend -= 1
if chf == 'n' and s[begin:end].strip() == 'null':
return None, end
elif chf == 't' and s[begin:end].strip() == 'true':
return True, end
elif chf == 'f' and s[begin:end].strip() == 'false':
return False, end
elif chf == '-' or chf >= '0' and chf <= '9':
m = NUMBER_RE.match(s, begin)
if m is not None and m.end() == end:
integer, frac, exp = m.groups()
if frac or exp:
res = context.parse_float(integer + (frac or '') + (exp or ''))
if int(res) == res and abs(res)<1e10: res = int(res)
else:
res = context.parse_int(integer)
return res, end
if isEol:
return s[begin:end].strip(), end
end += 1
def scanKeyName(s, end, encoding=None, strict=True):
"""Scan the string s for a JSON/Hjson key. see scanstring"""
ch, end = getNext(s, end)
if ch == '"' or ch == '\'':
return scanstring(s, end + 1, encoding, strict)
begin = end
space = -1
while 1:
ch = s[end:end + 1]
if ch == '':
raise HjsonDecodeError("Bad key name (eof)", s, end);
elif ch == ':':
if begin == end:
raise HjsonDecodeError("Found ':' but no key name (for an empty key name use quotes)", s, begin)
elif space >= 0:
if space != end - 1: raise HjsonDecodeError("Found whitespace in your key name (use quotes to include)", s, space)
return s[begin:end].rstrip(), end
else:
return s[begin:end], end
elif ch in WHITESPACE:
if space < 0 or space == end - 1: space = end
elif ch == '{' or ch == '}' or ch == '[' or ch == ']' or ch == ',':
raise HjsonDecodeError("Found '" + ch + "' where a key name was expected (check your syntax or use quotes if the key name includes {}[],: or whitespace)", s, begin)
end += 1
def make_scanner(context):
parse_object = context.parse_object
parse_array = context.parse_array
parse_string = context.parse_string
parse_mlstring = context.parse_mlstring
parse_tfnns = context.parse_tfnns
encoding = context.encoding
strict = context.strict
object_hook = context.object_hook
object_pairs_hook = context.object_pairs_hook
memo = context.memo
def _scan_once(string, idx):
try:
ch = string[idx]
except IndexError:
raise HjsonDecodeError('Expecting value', string, idx)
if ch == '"' or ch == '\'':
if string[idx:idx + 3] == '\'\'\'':
return parse_mlstring(string, idx)
else:
return parse_string(string, idx + 1, encoding, strict)
elif ch == '{':
return parse_object((string, idx + 1), encoding, strict,
_scan_once, object_hook, object_pairs_hook, memo)
elif ch == '[':
return parse_array((string, idx + 1), _scan_once)
return parse_tfnns(context, string, idx)
def scan_once(string, idx):
if idx < 0: raise HjsonDecodeError('Expecting value', string, idx)
try:
return _scan_once(string, idx)
finally:
memo.clear()
def scan_object_once(string, idx):
if idx < 0: raise HjsonDecodeError('Expecting value', string, idx)
try:
return parse_object((string, idx), encoding, strict,
_scan_once, object_hook, object_pairs_hook, memo, True)
finally:
memo.clear()
return scan_once, scan_object_once
def JSONObject(state, encoding, strict, scan_once, object_hook,
object_pairs_hook, memo=None, objectWithoutBraces=False):
(s, end) = state
# Backwards compatibility
if memo is None:
memo = {}
memo_get = memo.setdefault
pairs = []
ch, end = getNext(s, end)
# Trivial empty object
if not objectWithoutBraces and ch == '}':
if object_pairs_hook is not None:
result = object_pairs_hook(pairs)
return result, end + 1
pairs = {}
if object_hook is not None:
pairs = object_hook(pairs)
return pairs, end + 1
while True:
key, end = scanKeyName(s, end, encoding, strict)
key = memo_get(key, key)
ch, end = getNext(s, end)
if ch != ':':
raise HjsonDecodeError("Expecting ':' delimiter", s, end)
ch, end = getNext(s, end + 1)
value, end = scan_once(s, end)
pairs.append((key, value))
ch, end = getNext(s, end)
if ch == ',':
ch, end = getNext(s, end + 1)
if objectWithoutBraces:
if ch == '': break;
else:
if ch == '}':
end += 1
break
ch, end = getNext(s, end)
if object_pairs_hook is not None:
result = object_pairs_hook(pairs)
return result, end
pairs = dict(pairs)
if object_hook is not None:
pairs = object_hook(pairs)
return pairs, end
def JSONArray(state, scan_once):
(s, end) = state
values = []
ch, end = getNext(s, end)
# Look-ahead for trivial empty array
if ch == ']':
return values, end + 1
elif ch == '':
raise HjsonDecodeError("End of input while parsing an array (did you forget a closing ']'?)", s, end)
_append = values.append
while True:
value, end = scan_once(s, end)
_append(value)
ch, end = getNext(s, end)
if ch == ',':
ch, end = getNext(s, end + 1)
if ch == ']':
end += 1
break
ch, end = getNext(s, end)
return values, end
class HjsonDecoder(object):
"""Hjson decoder
Performs the following translations in decoding by default:
+---------------+-------------------+
| JSON | Python |
+===============+===================+
| object | dict |
+---------------+-------------------+
| array | list |
+---------------+-------------------+
| string | str, unicode |
+---------------+-------------------+
| number (int) | int, long |
+---------------+-------------------+
| number (real) | float |
+---------------+-------------------+
| true | True |
+---------------+-------------------+
| false | False |
+---------------+-------------------+
| null | None |
+---------------+-------------------+
"""
def __init__(self, encoding=None, object_hook=None, parse_float=None,
parse_int=None, strict=True,
object_pairs_hook=None):
"""
*encoding* determines the encoding used to interpret any
:class:`str` objects decoded by this instance (``'utf-8'`` by
default). It has no effect when decoding :class:`unicode` objects.
Note that currently only encodings that are a superset of ASCII work,
strings of other encodings should be passed in as :class:`unicode`.
*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 :class:`dict`. This can be used to provide custom
deserializations (e.g. to support JSON-RPC class hinting).
*object_pairs_hook* is an optional function that will be called with
the result of any object literal decode with an ordered list of pairs.
The return value of *object_pairs_hook* will be used instead of the
:class:`dict`. This feature can be used to implement custom decoders
that rely on the order that the key and value pairs are decoded (for
example, :func:`collections.OrderedDict` will remember the order of
insertion). If *object_hook* is also defined, the *object_pairs_hook*
takes priority.
*parse_float*, if specified, will be called with the string of every
JSON float to be decoded. By default, this is equivalent to
``float(num_str)``. This can be used to use another datatype or parser
for JSON floats (e.g. :class:`decimal.Decimal`).
*parse_int*, if specified, will be called with the string of every
JSON int to be decoded. By default, this is equivalent to
``int(num_str)``. This can be used to use another datatype or parser
for JSON integers (e.g. :class:`float`).
*strict* controls the parser's behavior when it encounters an
invalid control character in a string. The default setting of
``True`` means that unescaped control characters are parse errors, if
``False`` then control characters will be allowed in strings.
"""
if encoding is None:
encoding = DEFAULT_ENCODING
self.encoding = encoding
self.object_hook = object_hook
self.object_pairs_hook = object_pairs_hook
self.parse_float = parse_float or float
self.parse_int = parse_int or int
self.strict = strict
self.parse_object = JSONObject
self.parse_array = JSONArray
self.parse_string = scanstring
self.parse_mlstring = mlscanstring
self.parse_tfnns = scantfnns
self.memo = {}
(self.scan_once, self.scan_object_once) = make_scanner(self)
def decode(self, s, _PY3=PY3):
"""Return the Python representation of ``s`` (a ``str`` or ``unicode``
instance containing a JSON document)
"""
if _PY3 and isinstance(s, binary_type):
s = s.decode(self.encoding)
obj, end = self.raw_decode(s)
ch, end = getNext(s, end)
if end != len(s):
raise HjsonDecodeError("Extra data", s, end, len(s))
return obj
def raw_decode(self, s, idx=0, _PY3=PY3):
"""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.
Optionally, ``idx`` can be used to specify an offset in ``s`` where
the JSON document begins.
This can be used to decode a JSON document from a string that may
have extraneous data at the end.
"""
if idx < 0:
# Ensure that raw_decode bails on negative indexes, the regex
# would otherwise mask this behavior. #98
raise HjsonDecodeError('Expecting value', s, idx)
if _PY3 and not isinstance(s, text_type):
raise TypeError("Input string must be text")
# strip UTF-8 bom
if len(s) > idx:
ord0 = ord(s[idx])
if ord0 == 0xfeff:
idx += 1
elif ord0 == 0xef and s[idx:idx + 3] == '\xef\xbb\xbf':
idx += 3
start_index = idx
ch, idx = getNext(s, idx)
# If blank or comment only file, return dict
if start_index == 0 and ch == '':
return {}, 0
if ch == '{' or ch == '[':
return self.scan_once(s, idx)
else:
# assume we have a root object without braces
try:
return self.scan_object_once(s, idx)
except HjsonDecodeError as e:
# test if we are dealing with a single JSON value instead (true/false/null/num/"")
try:
return self.scan_once(s, idx)
except:
raise e
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