1 """JSON token scanner |
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2 """ |
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3 import re |
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4 try: |
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5 from simplejson._speedups import make_scanner as c_make_scanner |
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6 except ImportError: |
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7 c_make_scanner = None |
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8 |
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9 __all__ = ['make_scanner'] |
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10 |
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11 NUMBER_RE = re.compile( |
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12 r'(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]?\d+)?', |
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13 (re.VERBOSE | re.MULTILINE | re.DOTALL)) |
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14 |
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15 def py_make_scanner(context): |
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16 parse_object = context.parse_object |
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17 parse_array = context.parse_array |
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18 parse_string = context.parse_string |
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19 match_number = NUMBER_RE.match |
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20 encoding = context.encoding |
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21 strict = context.strict |
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22 parse_float = context.parse_float |
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23 parse_int = context.parse_int |
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24 parse_constant = context.parse_constant |
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25 object_hook = context.object_hook |
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26 |
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27 def _scan_once(string, idx): |
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28 try: |
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29 nextchar = string[idx] |
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30 except IndexError: |
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31 raise StopIteration |
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32 |
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33 if nextchar == '"': |
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34 return parse_string(string, idx + 1, encoding, strict) |
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35 elif nextchar == '{': |
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36 return parse_object((string, idx + 1), encoding, strict, _scan_once, object_hook) |
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37 elif nextchar == '[': |
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38 return parse_array((string, idx + 1), _scan_once) |
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39 elif nextchar == 'n' and string[idx:idx + 4] == 'null': |
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40 return None, idx + 4 |
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41 elif nextchar == 't' and string[idx:idx + 4] == 'true': |
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42 return True, idx + 4 |
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43 elif nextchar == 'f' and string[idx:idx + 5] == 'false': |
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44 return False, idx + 5 |
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45 |
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46 m = match_number(string, idx) |
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47 if m is not None: |
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48 integer, frac, exp = m.groups() |
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49 if frac or exp: |
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50 res = parse_float(integer + (frac or '') + (exp or '')) |
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51 else: |
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52 res = parse_int(integer) |
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53 return res, m.end() |
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54 elif nextchar == 'N' and string[idx:idx + 3] == 'NaN': |
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55 return parse_constant('NaN'), idx + 3 |
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56 elif nextchar == 'I' and string[idx:idx + 8] == 'Infinity': |
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57 return parse_constant('Infinity'), idx + 8 |
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58 elif nextchar == '-' and string[idx:idx + 9] == '-Infinity': |
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59 return parse_constant('-Infinity'), idx + 9 |
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60 else: |
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61 raise StopIteration |
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62 |
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63 return _scan_once |
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64 |
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65 make_scanner = c_make_scanner or py_make_scanner |
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