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| 1 | +/* This module exports part of the C API to the XDR routines into Python. |
| 2 | + * XDR is Sun's eXternal Data Representation, as described in RFC 1014. This |
| 3 | + * module is used by xdrlib.py to support the float and double data types |
| 4 | + * which are too much of a pain to support in Python directly. It is |
| 5 | + * not required by xdrlib.py -- when not available, these types aren't |
| 6 | + * supported at the Python layer. Note that representations that can be |
| 7 | + * implemented solely in Python, are *not* reproduced here. |
| 8 | + * |
| 9 | + * Module version number: 1.0 |
| 10 | + * |
| 11 | + * See xdrlib.py for usage notes. |
| 12 | + * |
| 13 | + * Note: this has so far, only been tested on Solaris 2.5 and SGI IRIX 5.3. |
| 14 | + * On these systems, you will need to link with -lnsl for these |
| 15 | + * symbols to be defined. |
| 16 | + */ |
| 17 | + |
| 18 | +#include "Python.h" |
| 19 | + |
| 20 | +#include <netconfig.h> |
| 21 | +#include <rpc/rpc.h> |
| 22 | +#include <rpc/xdr.h> |
| 23 | + |
| 24 | +static PyObject* xdr_error; |
| 25 | + |
| 26 | + |
| 27 | + |
| 28 | +static PyObject* |
| 29 | +pack_float(self, args) |
| 30 | + PyObject* self; |
| 31 | + PyObject* args; |
| 32 | +{ |
| 33 | + XDR xdr; |
| 34 | + float value; |
| 35 | + union { /* guarantees proper alignment */ |
| 36 | + long dummy; |
| 37 | + char buffer[4]; |
| 38 | + } addr; |
| 39 | + PyObject* rtn = NULL; |
| 40 | + |
| 41 | + if (!PyArg_ParseTuple(args, "f", &value)) |
| 42 | + return NULL; |
| 43 | + |
| 44 | + xdrmem_create(&xdr, addr.buffer, 4, XDR_ENCODE); |
| 45 | + if (xdr_float(&xdr, &value)) |
| 46 | + rtn = PyString_FromStringAndSize(addr.buffer, 4); |
| 47 | + else |
| 48 | + PyErr_SetString(xdr_error, "conversion from float failed"); |
| 49 | + |
| 50 | + xdr_destroy(&xdr); |
| 51 | + return rtn; |
| 52 | +} |
| 53 | + |
| 54 | +static PyObject* |
| 55 | +pack_double(self, args) |
| 56 | + PyObject* self; |
| 57 | + PyObject* args; |
| 58 | +{ |
| 59 | + XDR xdr; |
| 60 | + double value; |
| 61 | + union { /* guarantees proper alignment */ |
| 62 | + long dummy; |
| 63 | + char buffer[8]; |
| 64 | + } addr; |
| 65 | + PyObject* rtn = NULL; |
| 66 | + |
| 67 | + if (!PyArg_ParseTuple(args, "d", &value)) |
| 68 | + return NULL; |
| 69 | + |
| 70 | + xdrmem_create(&xdr, addr.buffer, 8, XDR_ENCODE); |
| 71 | + if (xdr_double(&xdr, &value)) |
| 72 | + rtn = PyString_FromStringAndSize(addr.buffer, 8); |
| 73 | + else |
| 74 | + PyErr_SetString(xdr_error, "conversion from double failed"); |
| 75 | + |
| 76 | + xdr_destroy(&xdr); |
| 77 | + return rtn; |
| 78 | +} |
| 79 | + |
| 80 | + |
| 81 | + |
| 82 | +static PyObject* |
| 83 | +unpack_float(self, args) |
| 84 | + PyObject* self; |
| 85 | + PyObject* args; |
| 86 | +{ |
| 87 | + XDR xdr; |
| 88 | + float value; |
| 89 | + char* string; |
| 90 | + int strlen; |
| 91 | + PyObject* rtn = NULL; |
| 92 | + |
| 93 | + if (!PyArg_ParseTuple(args, "s#", &string, &strlen)) |
| 94 | + return NULL; |
| 95 | + |
| 96 | + if (strlen != 4) { |
| 97 | + PyErr_SetString(PyExc_ValueError, "4 byte string expected"); |
| 98 | + return NULL; |
| 99 | + } |
| 100 | + |
| 101 | + /* Python guarantees that the string is 4 byte aligned */ |
| 102 | + xdrmem_create(&xdr, (caddr_t)string, 4, XDR_DECODE); |
| 103 | + if (xdr_float(&xdr, &value)) |
| 104 | + rtn = Py_BuildValue("f", value); |
| 105 | + else |
| 106 | + PyErr_SetString(xdr_error, "conversion to float failed"); |
| 107 | + |
| 108 | + xdr_destroy(&xdr); |
| 109 | + return rtn; |
| 110 | +} |
| 111 | + |
| 112 | + |
| 113 | +static PyObject* |
| 114 | +unpack_double(self, args) |
| 115 | + PyObject* self; |
| 116 | + PyObject* args; |
| 117 | +{ |
| 118 | + XDR xdr; |
| 119 | + double value; |
| 120 | + char* string; |
| 121 | + int strlen; |
| 122 | + PyObject* rtn; |
| 123 | + |
| 124 | + if (!PyArg_ParseTuple(args, "s#", &string, &strlen)) |
| 125 | + return NULL; |
| 126 | + |
| 127 | + if (strlen != 8) { |
| 128 | + PyErr_SetString(PyExc_ValueError, "8 byte string expected"); |
| 129 | + return NULL; |
| 130 | + } |
| 131 | + |
| 132 | + /* Python guarantees that the string is 4 byte aligned */ |
| 133 | + xdrmem_create(&xdr, (caddr_t)string, 8, XDR_DECODE); |
| 134 | + if (xdr_double(&xdr, &value)) |
| 135 | + rtn = Py_BuildValue("d", value); |
| 136 | + else |
| 137 | + PyErr_SetString(xdr_error, "conversion to double failed"); |
| 138 | + |
| 139 | + xdr_destroy(&xdr); |
| 140 | + return rtn; |
| 141 | +} |
| 142 | + |
| 143 | + |
| 144 | + |
| 145 | +static struct PyMethodDef |
| 146 | +xdr_methods[] = { |
| 147 | + {"pack_float", pack_float, 1}, |
| 148 | + {"pack_double", pack_double, 1}, |
| 149 | + {"unpack_float", unpack_float, 1}, |
| 150 | + {"unpack_double", unpack_double, 1}, |
| 151 | + {NULL, NULL, 0} /* sentinel */ |
| 152 | +}; |
| 153 | + |
| 154 | + |
| 155 | + |
| 156 | +void |
| 157 | +init_xdr() |
| 158 | +{ |
| 159 | + PyObject* module; |
| 160 | + PyObject* dict; |
| 161 | + |
| 162 | + module = Py_InitModule("_xdr", xdr_methods); |
| 163 | + dict = PyModule_GetDict(module); |
| 164 | + |
| 165 | + xdr_error = PyString_FromString("_xdr.error"); |
| 166 | + PyDict_SetItemString(dict, "error", xdr_error); |
| 167 | +} |
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