diff options
Diffstat (limited to 'numpy/core/_internal.py')
| -rw-r--r-- | numpy/core/_internal.py | 122 |
1 files changed, 79 insertions, 43 deletions
diff --git a/numpy/core/_internal.py b/numpy/core/_internal.py index 01741cd1a..84261f3ee 100644 --- a/numpy/core/_internal.py +++ b/numpy/core/_internal.py @@ -419,7 +419,49 @@ _pep3118_standard_map = { } _pep3118_standard_typechars = ''.join(_pep3118_standard_map.keys()) -def _dtype_from_pep3118(spec, byteorder='@', is_subdtype=False): +def _dtype_from_pep3118(spec): + + class Stream(object): + def __init__(self, s): + self.s = s + self.byteorder = '@' + + def advance(self, n): + res = self.s[:n] + self.s = self.s[n:] + return res + + def consume(self, c): + if self.s[:len(c)] == c: + self.advance(len(c)) + return True + return False + + def consume_until(self, c): + if callable(c): + i = 0 + while i < len(self.s) and not c(self.s[i]): + i = i + 1 + return self.advance(i) + else: + i = self.s.index(c) + res = self.advance(i) + self.advance(len(c)) + return res + + @property + def next(self): + return self.s[0] + + def __bool__(self): + return bool(self.s) + __nonzero__ = __bool__ + + stream = Stream(spec) + + return __dtype_from_pep3118(stream, is_subdtype=False) + +def __dtype_from_pep3118(stream, is_subdtype): fields = {} offset = 0 explicit_name = False @@ -429,6 +471,7 @@ def _dtype_from_pep3118(spec, byteorder='@', is_subdtype=False): dummy_name_index = [0] + def next_dummy_name(): dummy_name_index[0] += 1 @@ -439,31 +482,30 @@ def _dtype_from_pep3118(spec, byteorder='@', is_subdtype=False): return name next_dummy_name() + # Parse spec - while spec: + while stream: value = None # End of structure, bail out to upper level - if spec[0] == '}': - spec = spec[1:] + if stream.consume('}'): break # Sub-arrays (1) shape = None - if spec[0] == '(': - j = spec.index(')') - shape = tuple(map(int, spec[1:j].split(','))) - spec = spec[j+1:] + if stream.consume('('): + shape = stream.consume_until(')') + shape = tuple(map(int, shape.split(','))) # Byte order - if spec[0] in ('@', '=', '<', '>', '^', '!'): - byteorder = spec[0] + if stream.next in ('@', '=', '<', '>', '^', '!'): + byteorder = stream.advance(1) if byteorder == '!': byteorder = '>' - spec = spec[1:] + stream.byteorder = byteorder # Byte order characters also control native vs. standard type sizes - if byteorder in ('@', '^'): + if stream.byteorder in ('@', '^'): type_map = _pep3118_native_map type_map_chars = _pep3118_native_typechars else: @@ -471,39 +513,35 @@ def _dtype_from_pep3118(spec, byteorder='@', is_subdtype=False): type_map_chars = _pep3118_standard_typechars # Item sizes - itemsize = 1 - if spec[0].isdigit(): - j = 1 - for j in range(1, len(spec)): - if not spec[j].isdigit(): - break - itemsize = int(spec[:j]) - spec = spec[j:] + itemsize_str = stream.consume_until(lambda c: not c.isdigit()) + if itemsize_str: + itemsize = int(itemsize_str) + else: + itemsize = 1 # Data types is_padding = False - if spec[:2] == 'T{': - value, spec, align, next_byteorder = _dtype_from_pep3118( - spec[2:], byteorder=byteorder, is_subdtype=True) - elif spec[0] in type_map_chars: - next_byteorder = byteorder - if spec[0] == 'Z': - j = 2 + if stream.consume('T{'): + value, align = __dtype_from_pep3118( + stream, is_subdtype=True) + elif stream.next in type_map_chars: + if stream.next == 'Z': + typechar = stream.advance(2) else: - j = 1 - typechar = spec[:j] - spec = spec[j:] + typechar = stream.advance(1) + is_padding = (typechar == 'x') dtypechar = type_map[typechar] if dtypechar in 'USV': dtypechar += '%d' % itemsize itemsize = 1 - numpy_byteorder = {'@': '=', '^': '='}.get(byteorder, byteorder) + numpy_byteorder = {'@': '=', '^': '='}.get( + stream.byteorder, stream.byteorder) value = dtype(numpy_byteorder + dtypechar) align = value.alignment else: - raise ValueError("Unknown PEP 3118 data type specifier %r" % spec) + raise ValueError("Unknown PEP 3118 data type specifier %r" % stream.s) # # Native alignment may require padding @@ -512,7 +550,7 @@ def _dtype_from_pep3118(spec, byteorder='@', is_subdtype=False): # that the start of the array is *already* aligned. # extra_offset = 0 - if byteorder == '@': + if stream.byteorder == '@': start_padding = (-offset) % align intra_padding = (-value.itemsize) % align @@ -528,8 +566,7 @@ def _dtype_from_pep3118(spec, byteorder='@', is_subdtype=False): extra_offset += intra_padding # Update common alignment - common_alignment = (align*common_alignment - / _gcd(align, common_alignment)) + common_alignment = _lcm(align, common_alignment) # Convert itemsize to sub-array if itemsize != 1: @@ -541,10 +578,8 @@ def _dtype_from_pep3118(spec, byteorder='@', is_subdtype=False): # Field name this_explicit_name = False - if spec and spec.startswith(':'): - i = spec[1:].index(':') + 1 - name = spec[1:i] - spec = spec[i+1:] + if stream.consume(':'): + name = stream.consume_until(':') explicit_name = True this_explicit_name = True else: @@ -558,8 +593,6 @@ def _dtype_from_pep3118(spec, byteorder='@', is_subdtype=False): if not this_explicit_name: next_dummy_name() - byteorder = next_byteorder - offset += value.itemsize offset += extra_offset @@ -572,14 +605,14 @@ def _dtype_from_pep3118(spec, byteorder='@', is_subdtype=False): # Trailing padding must be explicitly added padding = offset - ret.itemsize - if byteorder == '@': + if stream.byteorder == '@': padding += (-offset) % common_alignment if is_padding and not this_explicit_name: ret = _add_trailing_padding(ret, padding) # Finished if is_subdtype: - return ret, spec, common_alignment, byteorder + return ret, common_alignment else: return ret @@ -626,6 +659,9 @@ def _gcd(a, b): a, b = b, a % b return a +def _lcm(a, b): + return a / _gcd(a, b) * b + # Exception used in shares_memory() class TooHardError(RuntimeError): pass |