1 | # Copyright (c) 2007, Robert Coup <robert.coup@onetrackmind.co.nz> |
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2 | # All rights reserved. |
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3 | # |
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4 | # Redistribution and use in source and binary forms, with or without modification, |
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5 | # are permitted provided that the following conditions are met: |
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6 | # |
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7 | # 1. Redistributions of source code must retain the above copyright notice, |
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8 | # this list of conditions and the following disclaimer. |
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9 | # |
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10 | # 2. Redistributions in binary form must reproduce the above copyright |
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11 | # notice, this list of conditions and the following disclaimer in the |
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12 | # documentation and/or other materials provided with the distribution. |
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13 | # |
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14 | # 3. Neither the name of Distance nor the names of its contributors may be used |
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15 | # to endorse or promote products derived from this software without |
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16 | # specific prior written permission. |
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17 | # |
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18 | # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND |
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19 | # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
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20 | # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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21 | # DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR |
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22 | # ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
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23 | # (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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24 | # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON |
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25 | # ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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26 | # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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27 | # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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28 | # |
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29 | """ |
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30 | Distance and Area objects to allow for sensible and convienient calculation |
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31 | and conversions. |
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32 | |
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33 | Authors: Robert Coup, Justin Bronn |
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34 | |
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35 | Inspired by GeoPy (http://exogen.case.edu/projects/geopy/) |
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36 | and Geoff Biggs' PhD work on dimensioned units for robotics. |
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37 | """ |
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38 | __all__ = ['A', 'Area', 'D', 'Distance', 'V', 'Volume', 'W', 'Weight'] |
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39 | from decimal import Decimal |
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40 | |
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41 | def is_number(obj): |
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42 | return isinstance(obj, (int, float, long, Decimal)) |
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43 | |
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44 | def pretty_name(obj): |
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45 | if obj.__class__ == type: |
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46 | return obj.__name__ |
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47 | return obj.__class__.__name__ |
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48 | |
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49 | class MeasureBase(object): |
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50 | |
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51 | STANDARD_UNIT = None |
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52 | ALIAS = {} |
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53 | UNITS = {} |
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54 | LALIAS = {} |
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55 | |
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56 | def __init__(self, default_unit=None, **kwargs): |
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57 | # The base unit is in meters. |
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58 | value, self._default_unit = self.default_units(kwargs) |
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59 | setattr(self, self.STANDARD_UNIT, value) |
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60 | if default_unit and isinstance(default_unit, str): |
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61 | self._default_unit = default_unit |
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62 | |
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63 | def _get_standard(self): |
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64 | return getattr(self, self.STANDARD_UNIT) |
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65 | |
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66 | def _set_standard(self, value): |
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67 | setattr(self, self.STANDARD_UNIT, value) |
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68 | |
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69 | standard = property(_get_standard, _set_standard) |
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70 | |
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71 | def __len__(self): |
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72 | return len(str(self)) |
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73 | |
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74 | def __getattr__(self, name): |
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75 | if name in self.UNITS: |
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76 | return self.standard / self.UNITS[name] |
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77 | else: |
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78 | raise AttributeError('Unknown unit type: %s' % name) |
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79 | |
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80 | def __repr__(self): |
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81 | return '%s(%s=%s)' % (pretty_name(self), self._default_unit, getattr(self, self._default_unit)) |
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82 | |
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83 | def __str__(self): |
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84 | val = getattr(self, self._default_unit) |
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85 | if val == int(val): |
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86 | val = int(val) |
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87 | return '%s %s' % (val, self._default_unit) |
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88 | |
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89 | def __cmp__(self, other): |
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90 | if isinstance(other, self.__class__): |
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91 | return cmp(self.standard, other.standard) |
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92 | else: |
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93 | return NotImplemented |
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94 | |
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95 | def __add__(self, other): |
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96 | if isinstance(other, self.__class__): |
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97 | return self.__class__(default_unit=self._default_unit, |
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98 | **{self.STANDARD_UNIT: (self.standard + other.standard)}) |
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99 | else: |
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100 | raise TypeError('%(class)s must be added with %(class)s' % {"class":pretty_name(self)}) |
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101 | |
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102 | def __iadd__(self, other): |
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103 | if isinstance(other, self.__class__): |
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104 | self.standard += other.standard |
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105 | return self |
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106 | else: |
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107 | raise TypeError('%(class)s must be added with %(class)s' % {"class":pretty_name(self)}) |
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108 | |
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109 | def __sub__(self, other): |
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110 | if isinstance(other, self.__class__): |
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111 | return self.__class__(default_unit=self._default_unit, |
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112 | **{self.STANDARD_UNIT: (self.standard - other.standard)}) |
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113 | else: |
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114 | raise TypeError('%(class)s must be subtracted from %(class)s' % {"class":pretty_name(self)}) |
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115 | |
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116 | def __isub__(self, other): |
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117 | if isinstance(other, self.__class__): |
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118 | self.standard -= other.standard |
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119 | return self |
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120 | else: |
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121 | raise TypeError('%(class)s must be subtracted from %(class)s' % {"class":pretty_name(self)}) |
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122 | |
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123 | def __mul__(self, other): |
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124 | if is_number(other): |
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125 | return self.__class__(default_unit=self._default_unit, |
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126 | **{self.STANDARD_UNIT: (self.standard * other)}) |
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127 | else: |
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128 | raise TypeError('%(class)s must be multiplied with number' % {"class":pretty_name(self)}) |
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129 | |
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130 | def __imul__(self, other): |
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131 | if is_number(other): |
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132 | self.standard *= float(other) |
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133 | return self |
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134 | else: |
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135 | raise TypeError('%(class)s must be multiplied with number' % {"class":pretty_name(self)}) |
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136 | |
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137 | def __rmul__(self, other): |
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138 | return self * other |
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139 | |
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140 | def __div__(self, other): |
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141 | if isinstance(other, self.__class__): |
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142 | return self.standard / other.standard |
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143 | if is_number(other): |
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144 | return self.__class__(default_unit=self._default_unit, |
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145 | **{self.STANDARD_UNIT: (self.standard / other)}) |
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146 | else: |
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147 | raise TypeError('%(class)s must be divided with number or %(class)s' % {"class":pretty_name(self)}) |
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148 | |
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149 | def __idiv__(self, other): |
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150 | if is_number(other): |
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151 | self.standard /= float(other) |
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152 | return self |
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153 | else: |
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154 | raise TypeError('%(class)s must be divided with number' % {"class":pretty_name(self)}) |
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155 | |
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156 | def __nonzero__(self): |
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157 | return bool(self.standard) |
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158 | |
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159 | def default_units(self, kwargs): |
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160 | """ |
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161 | Return the unit value and the default units specified |
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162 | from the given keyword arguments dictionary. |
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163 | """ |
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164 | val = 0.0 |
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165 | default_unit = self.STANDARD_UNIT |
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166 | for unit, value in kwargs.iteritems(): |
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167 | if not isinstance(value, float): value = float(value) |
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168 | if unit in self.UNITS: |
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169 | val += self.UNITS[unit] * value |
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170 | default_unit = unit |
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171 | elif unit in self.ALIAS: |
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172 | u = self.ALIAS[unit] |
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173 | val += self.UNITS[u] * value |
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174 | default_unit = u |
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175 | else: |
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176 | lower = unit.lower() |
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177 | if lower in self.UNITS: |
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178 | val += self.UNITS[lower] * value |
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179 | default_unit = lower |
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180 | elif lower in self.LALIAS: |
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181 | u = self.LALIAS[lower] |
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182 | val += self.UNITS[u] * value |
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183 | default_unit = u |
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184 | else: |
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185 | raise AttributeError('Unknown unit type: %s' % unit) |
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186 | return val, default_unit |
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187 | |
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188 | @classmethod |
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189 | def unit_attname(cls, unit_str): |
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190 | """ |
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191 | Retrieves the unit attribute name for the given unit string. |
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192 | For example, if the given unit string is 'metre', 'm' would be returned. |
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193 | An exception is raised if an attribute cannot be found. |
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194 | """ |
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195 | lower = unit_str.lower() |
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196 | if unit_str in cls.UNITS: |
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197 | return unit_str |
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198 | elif lower in cls.UNITS: |
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199 | return lower |
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200 | elif lower in cls.LALIAS: |
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201 | return cls.LALIAS[lower] |
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202 | else: |
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203 | raise Exception('Could not find a unit keyword associated with "%s"' % unit_str) |
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204 | |
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205 | class Distance(MeasureBase): |
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206 | STANDARD_UNIT = "m" |
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207 | UNITS = { |
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208 | 'chain' : 20.1168, |
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209 | 'chain_benoit' : 20.116782, |
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210 | 'chain_sears' : 20.1167645, |
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211 | 'british_chain_benoit' : 20.1167824944, |
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212 | 'british_chain_sears' : 20.1167651216, |
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213 | 'british_chain_sears_truncated' : 20.116756, |
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214 | 'cm' : 0.01, |
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215 | 'british_ft' : 0.304799471539, |
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216 | 'british_yd' : 0.914398414616, |
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217 | 'clarke_ft' : 0.3047972654, |
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218 | 'clarke_link' : 0.201166195164, |
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219 | 'fathom' : 1.8288, |
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220 | 'ft': 0.3048, |
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221 | 'german_m' : 1.0000135965, |
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222 | 'gold_coast_ft' : 0.304799710181508, |
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223 | 'indian_yd' : 0.914398530744, |
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224 | 'inch' : 0.0254, |
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225 | 'km': 1000.0, |
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226 | 'link' : 0.201168, |
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227 | 'link_benoit' : 0.20116782, |
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228 | 'link_sears' : 0.20116765, |
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229 | 'm': 1.0, |
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230 | 'mi': 1609.344, |
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231 | 'mm' : 0.001, |
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232 | 'nm': 1852.0, |
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233 | 'nm_uk' : 1853.184, |
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234 | 'rod' : 5.0292, |
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235 | 'sears_yd' : 0.91439841, |
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236 | 'survey_ft' : 0.304800609601, |
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237 | 'um' : 0.000001, |
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238 | 'yd': 0.9144, |
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239 | 'pt': 0.0254 / 72, |
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240 | } |
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241 | |
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242 | # Unit aliases for `UNIT` terms encountered in Spatial Reference WKT. |
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243 | ALIAS = { |
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244 | 'centimeter' : 'cm', |
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245 | 'foot' : 'ft', |
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246 | 'inches' : 'inch', |
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247 | 'kilometer' : 'km', |
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248 | 'kilometre' : 'km', |
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249 | 'meter' : 'm', |
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250 | 'metre' : 'm', |
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251 | 'micrometer' : 'um', |
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252 | 'micrometre' : 'um', |
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253 | 'millimeter' : 'mm', |
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254 | 'millimetre' : 'mm', |
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255 | 'mile' : 'mi', |
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256 | 'yard' : 'yd', |
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257 | 'British chain (Benoit 1895 B)' : 'british_chain_benoit', |
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258 | 'British chain (Sears 1922)' : 'british_chain_sears', |
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259 | 'British chain (Sears 1922 truncated)' : 'british_chain_sears_truncated', |
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260 | 'British foot (Sears 1922)' : 'british_ft', |
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261 | 'British foot' : 'british_ft', |
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262 | 'British yard (Sears 1922)' : 'british_yd', |
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263 | 'British yard' : 'british_yd', |
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264 | "Clarke's Foot" : 'clarke_ft', |
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265 | "Clarke's link" : 'clarke_link', |
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266 | 'Chain (Benoit)' : 'chain_benoit', |
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267 | 'Chain (Sears)' : 'chain_sears', |
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268 | 'Foot (International)' : 'ft', |
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269 | 'German legal metre' : 'german_m', |
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270 | 'Gold Coast foot' : 'gold_coast_ft', |
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271 | 'Indian yard' : 'indian_yd', |
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272 | 'Link (Benoit)': 'link_benoit', |
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273 | 'Link (Sears)': 'link_sears', |
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274 | 'Nautical Mile' : 'nm', |
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275 | 'Nautical Mile (UK)' : 'nm_uk', |
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276 | 'US survey foot' : 'survey_ft', |
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277 | 'U.S. Foot' : 'survey_ft', |
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278 | 'Yard (Indian)' : 'indian_yd', |
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279 | 'Yard (Sears)' : 'sears_yd', |
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280 | 'Point': 'pt', |
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281 | 'Pixel': 'pt', |
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282 | } |
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283 | LALIAS = dict([(k.lower(), v) for k, v in ALIAS.items()]) |
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284 | |
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285 | def __mul__(self, other): |
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286 | if isinstance(other, Area): |
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287 | return Volume(default_unit=VOLUME_PREFIX + self._default_unit, |
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288 | **{VOLUME_PREFIX + self.STANDARD_UNIT: (self.standard * other.standard)}) |
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289 | elif isinstance(other, self.__class__): |
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290 | return Area(default_unit=AREA_PREFIX + self._default_unit, |
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291 | **{AREA_PREFIX + self.STANDARD_UNIT: (self.standard * other.standard)}) |
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292 | elif is_number(other): |
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293 | return self.__class__(default_unit=self._default_unit, |
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294 | **{self.STANDARD_UNIT: (self.standard * other)}) |
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295 | else: |
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296 | raise TypeError('%(distance)s must be multiplied with number, %(distance)s or %(area)s' % { |
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297 | "distance" : pretty_name(self.__class__), |
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298 | "area" : pretty_name(Area), |
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299 | }) |
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300 | |
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301 | AREA_PREFIX = "sq_" |
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302 | |
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303 | class Area(MeasureBase): |
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304 | STANDARD_UNIT = AREA_PREFIX + Distance.STANDARD_UNIT |
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305 | # Getting the square units values and the alias dictionary. |
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306 | UNITS = dict([(AREA_PREFIX + k, v ** 2) for k, v in Distance.UNITS.items()]) |
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307 | ALIAS = dict([(k, AREA_PREFIX + v) for k, v in Distance.ALIAS.items()]) |
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308 | LALIAS = dict([(k.lower(), v) for k, v in ALIAS.items()]) |
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309 | |
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310 | def __div__(self, other): |
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311 | if isinstance(other, self.__class__): |
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312 | return self.standard / other.standard |
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313 | if isinstance(other, Distance): |
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314 | return Distance(default_unit=self._default_unit[len(AREA_PREFIX):], |
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315 | **{Distance.STANDARD_UNIT: (self.standard / other.standard)}) |
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316 | elif is_number(other): |
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317 | return self.__class__(default_unit=self._default_unit, |
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318 | **{self.STANDARD_UNIT: (self.standard / other)}) |
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319 | else: |
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320 | raise TypeError('%(area)s must be divided with number, %(distance)s or %(area)s' % { |
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321 | "distance" : pretty_name(Distance), |
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322 | "area" : pretty_name(self.__class__), |
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323 | }) |
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324 | |
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325 | def __mul__(self, other): |
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326 | if isinstance(other, Distance): |
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327 | return Volume(default_unit=VOLUME_PREFIX+self._default_unit[len(AREA_PREFIX):], |
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328 | **{Volume.STANDARD_UNIT: (self.standard * other.standard)}) |
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329 | elif is_number(other): |
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330 | return self.__class__(default_unit=self._default_unit, |
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331 | **{self.STANDARD_UNIT: (self.standard * other)}) |
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332 | else: |
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333 | raise TypeError('%(area)s must be multiplied with number or %(distance)s' % { |
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334 | "distance" : pretty_name(Distance), |
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335 | "area" : pretty_name(self.__class__), |
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336 | }) |
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337 | |
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338 | VOLUME_PREFIX = "vol_" |
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339 | |
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340 | class Volume(MeasureBase): |
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341 | STANDARD_UNIT = VOLUME_PREFIX + Distance.STANDARD_UNIT |
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342 | # Getting the cube units values and the alias dictionary. |
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343 | UNITS = dict([(VOLUME_PREFIX + k, v ** 3) for k, v in Distance.UNITS.items()]) |
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344 | ALIAS = dict([(k, VOLUME_PREFIX + v) for k, v in Distance.ALIAS.items()]) |
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345 | LALIAS = dict([(k.lower(), v) for k, v in ALIAS.items()]) |
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346 | |
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347 | def __div__(self, other): |
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348 | if isinstance(other, self.__class__): |
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349 | return self.standard / other.standard |
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350 | if isinstance(other, Area): |
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351 | return Distance(default_unit=self._default_unit[len(VOLUME_PREFIX):], |
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352 | **{Distance.STANDARD_UNIT: (self.standard / other.standard)}) |
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353 | if isinstance(other, Distance): |
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354 | return Area(default_unit=AREA_PREFIX+self._default_unit[len(VOLUME_PREFIX):], |
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355 | **{Area.STANDARD_UNIT: (self.standard / other.standard)}) |
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356 | elif is_number(other): |
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357 | return self.__class__(default_unit=self._default_unit, |
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358 | **{self.STANDARD_UNIT: (self.standard / other)}) |
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359 | else: |
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360 | raise TypeError('%(volume)s must be divided with number, %(distance)s, %(area)s or %(volume)s' % { |
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361 | "distance" : pretty_name(Distance), |
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362 | "area" : pretty_name(Area), |
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363 | "volume" : pretty_name(self.__class__), |
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364 | }) |
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365 | |
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366 | class Weight(MeasureBase): |
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367 | |
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368 | STANDARD_UNIT = "gr" |
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369 | |
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370 | UNITS = { |
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371 | 'mg': 1.0 / 1000, |
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372 | 'gr': 1.0, |
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373 | 'kg': 1.0 * 1000, |
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374 | 'q' : 1.0 * 1000 * 100, |
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375 | 'ton': 1.0 * 1000 * 1000, |
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376 | } |
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377 | |
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378 | # Unit aliases for `UNIT` terms encountered in Spatial Reference WKT. |
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379 | ALIAS = { |
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380 | 'Milligram': 'mg', |
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381 | 'Gram': 'gr', |
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382 | 'Kilogram': 'kg', |
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383 | 'Quintal' : 'q', |
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384 | 'Ton' : 'ton', |
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385 | } |
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386 | LALIAS = dict([(k.lower(), v) for k, v in ALIAS.items()]) |
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387 | |
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388 | # Shortcuts |
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389 | D = Distance |
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390 | A = Area |
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391 | V = Volume |
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392 | W = Weight |
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393 | |
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394 | |
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395 | if __name__ == '__main__': |
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396 | |
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397 | from itertools import product |
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398 | |
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399 | CONSTRUCTORS = { |
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400 | float: lambda cls, val: cls(val), |
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401 | A: lambda cls, val: cls(**{cls.STANDARD_UNIT:val}), |
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402 | D: lambda cls, val: cls(**{cls.STANDARD_UNIT:val}), |
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403 | V: lambda cls, val: cls(**{cls.STANDARD_UNIT:val}), |
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404 | } |
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405 | |
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406 | classes = [D, A, V, float] |
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407 | |
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408 | combs = product(classes, repeat = 2) |
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409 | |
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410 | a_val = 10 |
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411 | b_val = 5 |
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412 | |
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413 | for a_class, b_class in combs: |
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414 | |
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415 | print "-----------%s-vs-%s-----------" % (a_class.__name__.title(), b_class.__name__.title()) |
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416 | |
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417 | a = CONSTRUCTORS[a_class](a_class, a_val) |
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418 | b = CONSTRUCTORS[b_class](b_class, b_val) |
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419 | |
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420 | for verbose, operator in (("+", "__add__"), ("-", "__sub__"), ("*", "__mul__"), ("/", "__div__")): |
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421 | |
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422 | desc = "%s %s %s" % (a, verbose, b) |
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423 | |
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424 | print desc.ljust(25), "> ", |
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425 | |
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426 | try: |
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427 | print getattr(a, operator)(b).__repr__() |
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428 | except Exception, e: |
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429 | print e |
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430 | |
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