1 | /* -*- mode:c++ -*- */ |
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2 | |
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3 | /** @file |
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4 | |
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5 | Boost.Python conversion functions from STL containers to Python |
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6 | sequences and vice versa. |
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7 | |
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8 | $Id: pyconversions.h 575 2005-04-07 02:11:59Z mar637 $ |
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9 | |
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10 | */ |
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11 | |
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12 | #ifndef PY_CONVERSIONS_H |
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13 | #define PY_CONVERSIONS_H |
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14 | |
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15 | #include <vector> |
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16 | |
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17 | #include <boost/python.hpp> |
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18 | |
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19 | using namespace boost::python; |
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20 | |
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21 | /** A wrapper of a conversion function to convert a STL vector to a |
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22 | Python tuple. This class satisfies the requirements of the |
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23 | boost::python::to_python_converter conversion template argument. |
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24 | |
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25 | Copied from |
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26 | scitbx/include/scitbx/boost_python/container_conversions.h that is |
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27 | described in the <a |
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28 | href="http://www.boost.org/libs/python/doc/v2/faq.html"> |
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29 | Boost.Python FAQ. </a> |
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30 | |
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31 | @author Ralf W. Grosse-Kunstleve <rwgk@yahoo.com> of |
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32 | <a href="http://www.lbl.gov/">Lawrence Berkeley National Laboratory</a> |
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33 | */ |
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34 | template < typename ContainerType > |
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35 | struct to_tuple |
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36 | { |
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37 | /** Creates and returns a Python @c tuple from the elements copied |
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38 | from a STL container. The @c ContainerType must be a vector, |
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39 | but may contain any type of object supported by the |
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40 | boost::python::object constructor. */ |
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41 | static PyObject* convert (ContainerType const& c) |
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42 | { |
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43 | using boost::python::incref; // works around gcc 2.96 bug |
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44 | using boost::python::list; // dito |
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45 | list result; |
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46 | typename ContainerType::const_iterator i = c.begin(); |
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47 | for( ; i != c.end(); ++i) |
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48 | { |
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49 | result.append(*i); |
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50 | } |
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51 | return incref(tuple(result).ptr()); |
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52 | } |
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53 | }; |
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54 | |
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55 | /** Converts an STL vector of T objects to Python tuple. |
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56 | |
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57 | Copied from |
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58 | scitbx/include/scitbx/boost_python/container_conversions.h that is |
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59 | described in the <a |
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60 | href="http://www.boost.org/libs/python/doc/v2/faq.html"> |
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61 | Boost.Python FAQ. </a> |
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62 | |
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63 | @author Ralf W. Grosse-Kunstleve <rwgk@yahoo.com> of |
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64 | <a href="http://www.lbl.gov/">Lawrence Berkeley National Laboratory</a> |
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65 | */ |
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66 | template < typename T > |
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67 | struct std_vector_to_tuple |
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68 | { |
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69 | std_vector_to_tuple () |
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70 | { |
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71 | to_python_converter < std::vector < T >, |
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72 | to_tuple < std::vector < T > > > (); |
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73 | } |
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74 | }; |
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75 | |
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76 | // /** Interface to AxesType enumeration. */ |
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77 | // struct AxesOwner |
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78 | // { |
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79 | // public: |
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80 | // AxesOwner(){}; |
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81 | // typedef AxesType enum_type; |
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82 | // }; |
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83 | |
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84 | // /** Conversion of AxesType enumeration. */ |
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85 | // struct EnumTypeConverters |
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86 | // : python::enum_as_int_converters <AxesOwner::enum_type> |
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87 | // { |
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88 | // }; |
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89 | |
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90 | /** Default operations on all containers for conversion from Python |
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91 | container to C++ one. |
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92 | |
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93 | Copied from |
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94 | scitbx/include/scitbx/boost_python/container_conversions.h that is |
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95 | described in the <a |
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96 | href="http://www.boost.org/libs/python/doc/v2/faq.html"> |
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97 | Boost.Python FAQ. </a> |
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98 | |
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99 | @author Ralf W. Grosse-Kunstleve <rwgk@yahoo.com> of |
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100 | <a href="http://www.lbl.gov/">Lawrence Berkeley National Laboratory</a> |
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101 | */ |
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102 | struct default_policy |
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103 | { |
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104 | static bool check_convertibility_per_element() { return false; } |
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105 | |
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106 | template <typename ContainerType> |
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107 | static bool check_size(boost::type<ContainerType>, std::size_t sz) |
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108 | { |
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109 | return true; |
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110 | } |
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111 | |
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112 | template <typename ContainerType> |
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113 | static void assert_size(boost::type<ContainerType>, std::size_t sz) {} |
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114 | |
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115 | template <typename ContainerType> |
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116 | static void reserve(ContainerType& a, std::size_t sz) {} |
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117 | }; |
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118 | |
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119 | /** Operations on containers that have variable capacity for |
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120 | conversion from Python container to C++ one. |
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121 | |
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122 | Copied from |
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123 | scitbx/include/scitbx/boost_python/container_conversions.h that is |
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124 | described in the <a |
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125 | href="http://www.boost.org/libs/python/doc/v2/faq.html"> |
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126 | Boost.Python FAQ. </a> |
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127 | |
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128 | @author Ralf W. Grosse-Kunstleve <rwgk@yahoo.com> of |
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129 | <a href="http://www.lbl.gov/">Lawrence Berkeley National Laboratory</a> |
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130 | */ |
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131 | struct variable_capacity_policy : default_policy |
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132 | { |
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133 | template <typename ContainerType> |
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134 | static void reserve(ContainerType& a, std::size_t sz) |
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135 | { |
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136 | a.reserve(sz); |
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137 | } |
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138 | |
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139 | template <typename ContainerType, typename ValueType> |
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140 | static void set_value(ContainerType& a, std::size_t i, ValueType const& v) |
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141 | { |
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142 | assert(a.size() == i); |
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143 | a.push_back(v); |
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144 | } |
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145 | }; |
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146 | |
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147 | /** Conversion of Python sequence to C++ container. |
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148 | |
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149 | Copied from |
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150 | scitbx/include/scitbx/boost_python/container_conversions.h that is |
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151 | described in the <a |
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152 | href="http://www.boost.org/libs/python/doc/v2/faq.html"> |
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153 | Boost.Python FAQ. </a> |
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154 | |
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155 | @author Ralf W. Grosse-Kunstleve <rwgk@yahoo.com> of |
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156 | <a href="http://www.lbl.gov/">Lawrence Berkeley National Laboratory</a> |
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157 | */ |
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158 | template <typename ContainerType, typename ConversionPolicy> |
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159 | struct from_python_sequence |
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160 | { |
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161 | typedef typename ContainerType::value_type container_element_type; |
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162 | |
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163 | from_python_sequence() |
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164 | { |
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165 | boost::python::converter::registry::push_back( |
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166 | &convertible, |
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167 | &construct, |
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168 | boost::python::type_id<ContainerType>()); |
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169 | } |
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170 | |
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171 | /** Appears to return @a obj_ptr if it is type of Python sequence |
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172 | that can be convertible to C++ container. */ |
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173 | static void* convertible(PyObject* obj_ptr) |
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174 | { |
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175 | using namespace boost::python; |
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176 | using boost::python::allow_null; // works around gcc 2.96 bug |
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177 | { |
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178 | // Restriction to list, tuple, iter, xrange until |
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179 | // Boost.Python overload resolution is enhanced. |
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180 | // |
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181 | // add PySequence_Check() for numarray. |
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182 | // |
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183 | if (!( PyList_Check(obj_ptr) |
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184 | || PyTuple_Check(obj_ptr) |
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185 | || PyIter_Check(obj_ptr) |
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186 | || PyRange_Check(obj_ptr) |
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187 | || PySequence_Check(obj_ptr) )) return 0; |
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188 | } |
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189 | handle<> obj_iter(allow_null(PyObject_GetIter(obj_ptr))); |
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190 | if (!obj_iter.get()) { // must be convertible to an iterator |
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191 | PyErr_Clear(); |
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192 | return 0; |
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193 | } |
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194 | if (ConversionPolicy::check_convertibility_per_element()) { |
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195 | int obj_size = PyObject_Length(obj_ptr); |
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196 | if (obj_size < 0) { // must be a measurable sequence |
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197 | PyErr_Clear(); |
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198 | return 0; |
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199 | } |
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200 | if (!ConversionPolicy::check_size( |
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201 | boost::type<ContainerType>(), obj_size)) return 0; |
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202 | bool is_range = PyRange_Check(obj_ptr); |
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203 | //std::size_t i=0; |
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204 | int i = 0; |
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205 | #ifndef _MSC_VER // because it causes c1001: internal compiler error |
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206 | for(;;i++) { |
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207 | handle<> py_elem_hdl(allow_null(PyIter_Next(obj_iter.get()))); |
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208 | if (PyErr_Occurred()) { |
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209 | PyErr_Clear(); |
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210 | return 0; |
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211 | } |
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212 | if (!py_elem_hdl.get()) break; // end of iteration |
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213 | object py_elem_obj(py_elem_hdl); |
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214 | extract<container_element_type> elem_proxy(py_elem_obj); |
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215 | if (!elem_proxy.check()) return 0; |
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216 | if (is_range) break; // in a range all elements are of the same type |
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217 | } |
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218 | if (!is_range) assert(i == obj_size ); |
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219 | #endif |
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220 | } |
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221 | return obj_ptr; |
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222 | } |
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223 | |
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224 | /** Constructs a C++ container from a Python sequence. */ |
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225 | static void construct( |
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226 | PyObject* obj_ptr, |
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227 | boost::python::converter::rvalue_from_python_stage1_data* data) |
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228 | { |
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229 | using namespace boost::python; |
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230 | using boost::python::allow_null; // works around gcc 2.96 bug |
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231 | using boost::python::converter::rvalue_from_python_storage; // dito |
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232 | using boost::python::throw_error_already_set; // dito |
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233 | handle<> obj_iter(PyObject_GetIter(obj_ptr)); |
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234 | void* storage = ( |
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235 | (rvalue_from_python_storage<ContainerType>*) |
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236 | data)->storage.bytes; |
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237 | new (storage) ContainerType(); |
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238 | data->convertible = storage; |
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239 | ContainerType& result = *((ContainerType*)storage); |
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240 | std::size_t i=0; |
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241 | for(;;i++) { |
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242 | handle<> py_elem_hdl(allow_null(PyIter_Next(obj_iter.get()))); |
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243 | if (PyErr_Occurred()) throw_error_already_set(); |
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244 | if (!py_elem_hdl.get()) break; // end of iteration |
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245 | object py_elem_obj(py_elem_hdl); |
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246 | extract<container_element_type> elem_proxy(py_elem_obj); |
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247 | ConversionPolicy::set_value(result, i, elem_proxy()); |
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248 | } |
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249 | ConversionPolicy::assert_size(boost::type<ContainerType>(), i); |
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250 | } |
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251 | |
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252 | }; |
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253 | |
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254 | #endif // PY_CONVERSIONS_H |
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