Modules/xreadlinesmodule.c

   1 #include "Python.h"
   2
   3 PyDoc_STRVAR(xreadlines_doc,
   4 "xreadlines(f)\n\
   5 \n\
   6 Return an xreadlines object for the file f.");
   7
   8 typedef struct {
   9         PyObject_HEAD
  10         PyObject *file;
  11         PyObject *lines;
  12         int lineslen;
  13         int lineno;
  14         int abslineno;
  15 } PyXReadlinesObject;
  16
  17 static PyTypeObject XReadlinesObject_Type;
  18
  19 static void
  20 xreadlines_dealloc(PyXReadlinesObject *op)
  21 {
  22         Py_XDECREF(op->file);
  23         Py_XDECREF(op->lines);
  24         PyObject_DEL(op);
  25 }
  26
  27 /* A larger chunk size doesn't seem to make a difference */
  28 #define CHUNKSIZE  8192
  29
  30 static PyXReadlinesObject *
  31 newreadlinesobject(PyObject *file)
  32 {
  33         PyXReadlinesObject *op;
  34         op = PyObject_NEW(PyXReadlinesObject, &XReadlinesObject_Type);
  35         if (op == NULL)
  36                 return NULL;
  37         Py_XINCREF(file);
  38         op->file = file;
  39         op->lines = NULL;
  40         op->abslineno = op->lineno = op->lineslen = 0;
  41         return op;
  42 }
  43
  44 static PyObject *
  45 xreadlines(PyObject *self, PyObject *args)
  46 {
  47         PyObject *file;
  48         PyXReadlinesObject *ret;
  49
  50         if (!PyArg_ParseTuple(args, "O:xreadlines", &file))
  51                 return NULL;
  52         ret = newreadlinesobject(file);
  53         return (PyObject*)ret;
  54 }
  55
  56 static PyObject *
  57 xreadlines_common(PyXReadlinesObject *a)
  58 {
  59         if (a->lineno >= a->lineslen) {
  60                 Py_XDECREF(a->lines);
  61                 a->lines = PyObject_CallMethod(a->file, "readlines", "(i)",
  62                                                CHUNKSIZE);
  63                 if (a->lines == NULL)
  64                         return NULL;
  65                 a->lineno = 0;
  66                 if ((a->lineslen = PySequence_Size(a->lines)) < 0)
  67                         return NULL;
  68         }
  69         a->abslineno++;
  70         return PySequence_GetItem(a->lines, a->lineno++);
  71 }
  72
  73 static PyObject *
  74 xreadlines_item(PyXReadlinesObject *a, int i)
  75 {
  76         if (i != a->abslineno) {
  77                 PyErr_SetString(PyExc_RuntimeError,
  78                         "xreadlines object accessed out of order");
  79                 return NULL;
  80         }
  81         return xreadlines_common(a);
  82 }
  83
  84 static PyObject *
  85 xreadlines_getiter(PyXReadlinesObject *a)
  86 {
  87         Py_INCREF(a);
  88         return (PyObject *)a;
  89 }
  90
  91 static PyObject *
  92 xreadlines_iternext(PyXReadlinesObject *a)
  93 {
  94         PyObject *res;
  95
  96         res = xreadlines_common(a);
  97         if (res == NULL && PyErr_ExceptionMatches(PyExc_IndexError))
  98                 PyErr_Clear();
  99         return res;
 100 }
 101
 102 static PyObject *
 103 xreadlines_next(PyXReadlinesObject *a, PyObject *args)
 104 {
 105         PyObject *res;
 106
 107         if (!PyArg_ParseTuple(args, ""))
 108                 return NULL;
 109         res = xreadlines_common(a);
 110         if (res == NULL && PyErr_ExceptionMatches(PyExc_IndexError))
 111                 PyErr_SetObject(PyExc_StopIteration, Py_None);
 112         return res;
 113 }
 114
 115 PyDoc_STRVAR(next_doc, "x.next() -> the next line or raise StopIteration");
 116
 117 static PyMethodDef xreadlines_methods[] = {
 118         {"next", (PyCFunction)xreadlines_next, METH_VARARGS, next_doc},
 119         {NULL, NULL}
 120 };
 121
 122 static PyObject *
 123 xreadlines_getattr(PyObject *a, char *name)
 124 {
 125         return Py_FindMethod(xreadlines_methods, a, name);
 126 }
 127
 128 static PySequenceMethods xreadlines_as_sequence = {
 129         0, /*sq_length*/
 130         0, /*sq_concat*/
 131         0, /*sq_repeat*/
 132         (intargfunc)xreadlines_item, /*sq_item*/
 133 };
 134
 135 static PyTypeObject XReadlinesObject_Type = {
 136         PyObject_HEAD_INIT(NULL)
 137         0,
 138         "xreadlines.xreadlines",
 139         sizeof(PyXReadlinesObject),
 140         0,
 141         (destructor)xreadlines_dealloc,         /* tp_dealloc */
 142         0,                                      /* tp_print */
 143         xreadlines_getattr,                     /* tp_getattr */
 144         0,                                      /* tp_setattr */
 145         0,                                      /* tp_compare */
 146         0,                                      /* tp_repr */
 147         0,                                      /* tp_as_number */
 148         &xreadlines_as_sequence,                /* tp_as_sequence */
 149         0,                                      /* tp_as_mapping */
 150         0,                                      /* tp_hash */
 151         0,                                      /* tp_call */
 152         0,                                      /* tp_str */
 153         0,                                      /* tp_getattro */
 154         0,                                      /* tp_setattro */
 155         0,                                      /* tp_as_buffer */
 156         Py_TPFLAGS_DEFAULT,                     /* tp_flags */
 157         0,                                      /* tp_doc */
 158         0,                                      /* tp_traverse */
 159         0,                                      /* tp_clear */
 160         0,                                      /* tp_richcompare */
 161         0,                                      /* tp_weaklistoffset */
 162         (getiterfunc)xreadlines_getiter,        /* tp_iter */
 163         (iternextfunc)xreadlines_iternext,      /* tp_iternext */
 164 };
 165
 166 static PyMethodDef xreadlines_functions[] = {
 167         {"xreadlines", xreadlines, METH_VARARGS, xreadlines_doc},
 168         {NULL, NULL}
 169 };
 170
 171 PyMODINIT_FUNC
 172 initxreadlines(void)
 173 {
 174         XReadlinesObject_Type.ob_type = &PyType_Type;
 175         Py_InitModule("xreadlines", xreadlines_functions);
 176         PyErr_Warn(PyExc_DeprecationWarning,
 177                    "xreadlines is deprecated; use 'for line in file'.");
 178 }