Source Code for Module glitter.utils.dtypes

  1  """Datatypes and helper functions. 
  2   
  3  @author: Stephan Wenger 
  4  @date: 2012-02-29 
  5  """ 
  6   
  7  import numpy as _np 
  8   
  9  import glitter.raw as _gl 
 10   
 11 -class Datatype(object): 
 12      _nptype_db = {} 
 13      _gltype_db = {} 
 14      _db = {} 
 15   
 16 -    def __init__(self, integer, signed, nptype, _gltype=None, charcode=None): 
 17          self._integer = bool(integer) 
 18          self._signed = bool(signed) 
 19          self._nptype = nptype 
 20          self._gltype = _gltype 
 21          self._charcode = charcode 
 22          self._nbytes = nptype().itemsize 
 23   
 24          Datatype._nptype_db[self._nptype] = self 
 25          Datatype._gltype_db[self._gltype] = self 
 26          Datatype._db[self._integer, self._signed, self._nbytes] = self 
 27   
 28      @classmethod 
 29 -    def from_numpy(cls, nptype): 
 30          try: 
 31              return cls._nptype_db[nptype] 
 32          except KeyError: 
 33              return cls._nptype_db[nptype.type] 
 34   
 35      @classmethod 
 36 -    def _from_gl(cls, _gltype): 
 37          return cls._gltype_db[_gltype] 
 38   
 39 -    def as_numpy(self): 
 40          return self._nptype 
 41   
 42 -    def _as_gl(self): 
 43          return self._gltype 
 44   
 45 -    def as_signed(self): 
 46          return Datatype._db[self.is_integer(), True, self.nbytes] 
 47   
 48 -    def as_unsigned(self): 
 49          return Datatype._db[self.is_integer(), False, self.nbytes] 
 50   
 51 -    def as_nbytes(self, nbytes): 
 52          return Datatype._db[self.is_integer(), self.is_signed(), nbytes] 
 53   
 54 -    def is_signed(self): 
 55          return self._signed 
 56   
 57 -    def is_unsigned(self): 
 58          return not self._signed 
 59   
 60 -    def is_integer(self): 
 61          return self._integer 
 62   
 63 -    def is_float(self): 
 64          return not self._integer 
 65   
 66 -    def is_boolean(self): 
 67          return self == bool8 
 68   
 69      @property 
 70 -    def charcode(self): 
 71          return self._charcode 
 72   
 73      @property 
 74 -    def nbytes(self): 
 75          return self._nbytes 
 76   
 77 -    def __str__(self): 
 78          return "%s%s%d" % ("u" if self.is_unsigned() else "", "int" if self.is_integer() else "float", 8 * self.nbytes) 
 79   
 80 -    def __repr__(self): 
 81          return str(self) 
 82   
 83 -    def coerced(self, force_integer=False, force_unsigned=False, force_float=False, force_gl=True): 
 84          """Find a datatype with the specified properties. 
 85   
 86          The returned datatype will match `self` as closely as possible. 
 87          If `force_integer` is `True`, it will be an integer datatype. 
 88          If `force_unsigned` is `True`, it will be an unsigned datatype. 
 89          If `force_float` is `True`, it will be a floating point datatype. 
 90          If `force_gl` is `True`, it will have an OpenGL equivalent. 
 91   
 92          If conversion of `self` to the resulting datatype would likely result in a 
 93          severe loss of precision or overflows, an error may be raised. 
 94          """ 
 95   
 96          if force_integer and not self.is_integer(): 
 97              raise TypeError("no matching datatype") 
 98          if force_float and not self.is_float(): 
 99              raise TypeError("no matching datatype") 
100   
101          dtype = self 
102          if force_unsigned and not dtype.is_unsigned(): 
103              dtype = dtype.as_unsigned() 
104          while force_gl and dtype._as_gl() is None: 
105              dtype = dtype.as_nbytes(dtype.nbytes / 2) 
106          return dtype 
107   
108  bool8 = Datatype(integer=True, signed=True, nptype=_np.bool8, _gltype=_gl.GL_BOOL, charcode="b") 
109  uint8 = Datatype(integer=True, signed=False, nptype=_np.uint8, _gltype=_gl.GL_UNSIGNED_BYTE, charcode="ub") 
110  uint16 = Datatype(integer=True, signed=False, nptype=_np.uint16, _gltype=_gl.GL_UNSIGNED_SHORT) 
111  uint32 = Datatype(integer=True, signed=False, nptype=_np.uint32, _gltype=_gl.GL_UNSIGNED_INT, charcode="ui") 
112  uint64 = Datatype(integer=True, signed=False, nptype=_np.uint64, charcode="ui64") 
113  int8 = Datatype(integer=True, signed=True, nptype=_np.int8, _gltype=_gl.GL_BYTE) 
114  int16 = Datatype(integer=True, signed=True, nptype=_np.int16, _gltype=_gl.GL_SHORT) 
115  int32 = Datatype(integer=True, signed=True, nptype=_np.int32, _gltype=_gl.GL_INT, charcode="i") 
116  int64 = Datatype(integer=True, signed=True, nptype=_np.int64, charcode="i64") 
117  float32 = Datatype(integer=False, signed=True, nptype=_np.float32, _gltype=_gl.GL_FLOAT, charcode="f") 
118  float64 = Datatype(integer=False, signed=True, nptype=_np.float64, charcode="d") # GL_DOUBLE exists but is not supported by, e.g., textures 
119   
120 -def coerce_array(data, dtype=None, force_integer=False, force_unsigned=False, force_float=False, force_gl=True): 
121      """Convert `data` to a contiguous array with the specified properties. 
122   
123      The datatype of the array will match `dtype` as closely as possible. 
124      If `force_integer` is `True`, it will be an integer datatype. 
125      If `force_unsigned` is `True`, it will be an unsigned datatype. 
126      If `force_float` is `True`, it will be a floating point datatype. 
127      If `force_gl` is `True`, it will have an OpenGL equivalent. 
128   
129      If conversion to the resulting datatype would likely result in a severe 
130      loss of precision or overflows, an error may be raised. 
131      """ 
132   
133      if dtype is None: 
134          if hasattr(data, "dtype"): 
135              dtype = Datatype.from_numpy(data.dtype) 
136          else: 
137              if force_integer: 
138                  dtype = int32 
139              else: 
140                  dtype = float32 
141      dtype = dtype.coerced(force_integer, force_unsigned, force_float, force_gl) 
142   
143      return _np.ascontiguousarray(data, dtype.as_numpy()) 
144   
145  __all__ = [ 
146      "Datatype", 
147      "coerce_array", 
148      "bool8", 
149      "uint8", 
150      "uint16", 
151      "uint32", 
152      "uint64", 
153      "int8", 
154      "int16", 
155      "int32", 
156      "int64", 
157      "float32", 
158      "float64", 
159  ] 
160