cpython/Objects/structseq.c at 3.5 · python/cpython · GitHub

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/* Implementation helper: a struct that looks like a tuple. See timemodule

and posixmodule for example uses. */

#include "Python.h"

#include "structmember.h"

static char visible_length_key[] = "n_sequence_fields";

static char real_length_key[] = "n_fields";

static char unnamed_fields_key[] = "n_unnamed_fields";

/* Fields with this name have only a field index, not a field name.

They are only allowed for indices < n_visible_fields. */

char *PyStructSequence_UnnamedField = "unnamed field";

_Py_IDENTIFIER(n_sequence_fields);

_Py_IDENTIFIER(n_fields);

_Py_IDENTIFIER(n_unnamed_fields);

#define VISIBLE_SIZE(op) Py_SIZE(op)

#define VISIBLE_SIZE_TP(tp) PyLong_AsLong( \

_PyDict_GetItemId((tp)->tp_dict, &PyId_n_sequence_fields))

#define REAL_SIZE_TP(tp) PyLong_AsLong( \

_PyDict_GetItemId((tp)->tp_dict, &PyId_n_fields))

#define REAL_SIZE(op) REAL_SIZE_TP(Py_TYPE(op))

#define UNNAMED_FIELDS_TP(tp) PyLong_AsLong( \

_PyDict_GetItemId((tp)->tp_dict, &PyId_n_unnamed_fields))

#define UNNAMED_FIELDS(op) UNNAMED_FIELDS_TP(Py_TYPE(op))

PyObject *

PyStructSequence_New(PyTypeObject *type)

{

PyStructSequence *obj;

Py_ssize_t size = REAL_SIZE_TP(type), i;

obj = PyObject_GC_NewVar(PyStructSequence, type, size);

if (obj == NULL)

return NULL;

/* Hack the size of the variable object, so invisible fields don't appear

to Python code. */

Py_SIZE(obj) = VISIBLE_SIZE_TP(type);

for (i = 0; i < size; i++)

obj->ob_item[i] = NULL;

return (PyObject*)obj;

}

void

PyStructSequence_SetItem(PyObject* op, Py_ssize_t i, PyObject* v)

{

PyStructSequence_SET_ITEM(op, i, v);

}

PyObject*

PyStructSequence_GetItem(PyObject* op, Py_ssize_t i)

{

return PyStructSequence_GET_ITEM(op, i);

}

static void

structseq_dealloc(PyStructSequence *obj)

{

Py_ssize_t i, size;

size = REAL_SIZE(obj);

for (i = 0; i < size; ++i) {

Py_XDECREF(obj->ob_item[i]);

}

PyObject_GC_Del(obj);

}

static PyObject *

structseq_new(PyTypeObject *type, PyObject *args, PyObject *kwds)

{

PyObject *arg = NULL;

PyObject *dict = NULL;

PyObject *ob;

PyStructSequence *res = NULL;

Py_ssize_t len, min_len, max_len, i, n_unnamed_fields;

static char *kwlist[] = {"sequence", "dict", 0};

if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|O:structseq",

kwlist, &arg, &dict))

return NULL;

arg = PySequence_Fast(arg, "constructor requires a sequence");

if (!arg) {

return NULL;

}

if (dict && !PyDict_Check(dict)) {

PyErr_Format(PyExc_TypeError,

"%.500s() takes a dict as second arg, if any",

type->tp_name);

Py_DECREF(arg);

return NULL;

}

len = PySequence_Fast_GET_SIZE(arg);

min_len = VISIBLE_SIZE_TP(type);

max_len = REAL_SIZE_TP(type);

n_unnamed_fields = UNNAMED_FIELDS_TP(type);

if (min_len != max_len) {

if (len < min_len) {

PyErr_Format(PyExc_TypeError,

"%.500s() takes an at least %zd-sequence (%zd-sequence given)",

type->tp_name, min_len, len);

Py_DECREF(arg);

return NULL;

}

if (len > max_len) {

PyErr_Format(PyExc_TypeError,

"%.500s() takes an at most %zd-sequence (%zd-sequence given)",

type->tp_name, max_len, len);

Py_DECREF(arg);

return NULL;

}

else {

if (len != min_len) {

PyErr_Format(PyExc_TypeError,

"%.500s() takes a %zd-sequence (%zd-sequence given)",

type->tp_name, min_len, len);

Py_DECREF(arg);

return NULL;

}

res = (PyStructSequence*) PyStructSequence_New(type);

if (res == NULL) {

Py_DECREF(arg);

return NULL;

}

for (i = 0; i < len; ++i) {

PyObject *v = PySequence_Fast_GET_ITEM(arg, i);

Py_INCREF(v);

res->ob_item[i] = v;

}

for (; i < max_len; ++i) {

if (dict && (ob = PyDict_GetItemString(

dict, type->tp_members[i-n_unnamed_fields].name))) {

}

else {

ob = Py_None;

}

Py_INCREF(ob);

res->ob_item[i] = ob;

}

Py_DECREF(arg);

return (PyObject*) res;

}

static PyObject *

structseq_repr(PyStructSequence *obj)

{

/* buffer and type size were chosen well considered. */

#define REPR_BUFFER_SIZE 512

#define TYPE_MAXSIZE 100

PyTypeObject *typ = Py_TYPE(obj);

int i, removelast = 0;

Py_ssize_t len;

char buf[REPR_BUFFER_SIZE];

char *endofbuf, *pbuf = buf;

/* pointer to end of writeable buffer; safes space for "...)\0" */

endofbuf= &buf[REPR_BUFFER_SIZE-5];

/* "typename(", limited to TYPE_MAXSIZE */

len = strlen(typ->tp_name) > TYPE_MAXSIZE ? TYPE_MAXSIZE :

strlen(typ->tp_name);

strncpy(pbuf, typ->tp_name, len);

pbuf += len;

*pbuf++ = '(';

for (i=0; i < VISIBLE_SIZE(obj); i++) {

PyObject *val, *repr;

char *cname, *crepr;

cname = typ->tp_members[i].name;

if (cname == NULL) {

PyErr_Format(PyExc_SystemError, "In structseq_repr(), member %d name is NULL"

" for type %.500s", i, typ->tp_name);

return NULL;

}

val = PyStructSequence_GET_ITEM(obj, i);

repr = PyObject_Repr(val);

if (repr == NULL)

return NULL;

crepr = _PyUnicode_AsString(repr);

if (crepr == NULL) {

Py_DECREF(repr);

return NULL;

}

/* + 3: keep space for "=" and ", " */

len = strlen(cname) + strlen(crepr) + 3;

if ((pbuf+len) <= endofbuf) {

strcpy(pbuf, cname);

pbuf += strlen(cname);

*pbuf++ = '=';

strcpy(pbuf, crepr);

pbuf += strlen(crepr);

*pbuf++ = ',';

*pbuf++ = ' ';

removelast = 1;

Py_DECREF(repr);

}

else {

strcpy(pbuf, "...");

pbuf += 3;

removelast = 0;

Py_DECREF(repr);

break;

}

if (removelast) {

/* overwrite last ", " */

pbuf-=2;

}

*pbuf++ = ')';

*pbuf = '\0';

return PyUnicode_FromString(buf);

}

static PyObject *

structseq_reduce(PyStructSequence* self)

{

PyObject* tup = NULL;

PyObject* dict = NULL;

PyObject* result;

Py_ssize_t n_fields, n_visible_fields, n_unnamed_fields;

int i;

n_fields = REAL_SIZE(self);

n_visible_fields = VISIBLE_SIZE(self);

n_unnamed_fields = UNNAMED_FIELDS(self);

tup = PyTuple_New(n_visible_fields);

if (!tup)

goto error;

dict = PyDict_New();

if (!dict)

goto error;

for (i = 0; i < n_visible_fields; i++) {

Py_INCREF(self->ob_item[i]);

PyTuple_SET_ITEM(tup, i, self->ob_item[i]);

}

for (; i < n_fields; i++) {

char *n = Py_TYPE(self)->tp_members[i-n_unnamed_fields].name;

if (PyDict_SetItemString(dict, n, self->ob_item[i]) < 0)

goto error;

}

result = Py_BuildValue("(O(OO))", Py_TYPE(self), tup, dict);

Py_DECREF(tup);

Py_DECREF(dict);

return result;

error:

Py_XDECREF(tup);

Py_XDECREF(dict);

return NULL;

}

static PyMethodDef structseq_methods[] = {

{"__reduce__", (PyCFunction)structseq_reduce, METH_NOARGS, NULL},

{NULL, NULL}

};

static PyTypeObject _struct_sequence_template = {

PyVarObject_HEAD_INIT(&PyType_Type, 0)

NULL, /* tp_name */

sizeof(PyStructSequence) - sizeof(PyObject *), /* tp_basicsize */

sizeof(PyObject *), /* tp_itemsize */

(destructor)structseq_dealloc, /* tp_dealloc */

0, /* tp_print */

0, /* tp_getattr */

0, /* tp_setattr */

0, /* tp_reserved */

(reprfunc)structseq_repr, /* tp_repr */

0, /* tp_as_number */

0, /* tp_as_sequence */

0, /* tp_as_mapping */

0, /* tp_hash */

0, /* tp_call */

0, /* tp_str */

0, /* tp_getattro */

0, /* tp_setattro */

0, /* tp_as_buffer */

Py_TPFLAGS_DEFAULT, /* tp_flags */

NULL, /* tp_doc */

0, /* tp_traverse */

0, /* tp_clear */

0, /* tp_richcompare */

0, /* tp_weaklistoffset */

0, /* tp_iter */

0, /* tp_iternext */

structseq_methods, /* tp_methods */

NULL, /* tp_members */

0, /* tp_getset */

0, /* tp_base */

0, /* tp_dict */

0, /* tp_descr_get */

0, /* tp_descr_set */

0, /* tp_dictoffset */

0, /* tp_init */

0, /* tp_alloc */

structseq_new, /* tp_new */

};

int

PyStructSequence_InitType2(PyTypeObject *type, PyStructSequence_Desc *desc)

{

PyObject *dict;

PyMemberDef* members;

int n_members, n_unnamed_members, i, k;

PyObject *v;

#ifdef Py_TRACE_REFS

/* if the type object was chained, unchain it first

before overwriting its storage */

if (type->ob_base.ob_base._ob_next) {

_Py_ForgetReference((PyObject*)type);

}

#endif

n_unnamed_members = 0;

for (i = 0; desc->fields[i].name != NULL; ++i)

if (desc->fields[i].name == PyStructSequence_UnnamedField)

n_unnamed_members++;

n_members = i;

memcpy(type, &_struct_sequence_template, sizeof(PyTypeObject));

type->tp_base = &PyTuple_Type;

type->tp_name = desc->name;

type->tp_doc = desc->doc;

members = PyMem_NEW(PyMemberDef, n_members-n_unnamed_members+1);

if (members == NULL) {

PyErr_NoMemory();

return -1;

}

for (i = k = 0; i < n_members; ++i) {

if (desc->fields[i].name == PyStructSequence_UnnamedField)

continue;

members[k].name = desc->fields[i].name;

members[k].type = T_OBJECT;

members[k].offset = offsetof(PyStructSequence, ob_item)

+ i * sizeof(PyObject*);

members[k].flags = READONLY;

members[k].doc = desc->fields[i].doc;

k++;

}

members[k].name = NULL;

type->tp_members = members;

if (PyType_Ready(type) < 0)

return -1;

Py_INCREF(type);

dict = type->tp_dict;

#define SET_DICT_FROM_INT(key, value) \

do { \

v = PyLong_FromLong((long) value); \

if (v == NULL) \

return -1; \

if (PyDict_SetItemString(dict, key, v) < 0) { \

Py_DECREF(v); \

return -1; \

} \

Py_DECREF(v); \

} while (0)

SET_DICT_FROM_INT(visible_length_key, desc->n_in_sequence);

SET_DICT_FROM_INT(real_length_key, n_members);

SET_DICT_FROM_INT(unnamed_fields_key, n_unnamed_members);

return 0;

}

void

PyStructSequence_InitType(PyTypeObject *type, PyStructSequence_Desc *desc)

{

(void)PyStructSequence_InitType2(type, desc);

}

PyTypeObject*

PyStructSequence_NewType(PyStructSequence_Desc *desc)

{

PyTypeObject *result;

result = (PyTypeObject*)PyType_GenericAlloc(&PyType_Type, 0);

if (result == NULL)

return NULL;

if (PyStructSequence_InitType2(result, desc) < 0) {

Py_DECREF(result);

return NULL;

}

return result;

}

int _PyStructSequence_Init(void)

{

if (_PyUnicode_FromId(&PyId_n_sequence_fields) == NULL

|| _PyUnicode_FromId(&PyId_n_fields) == NULL

|| _PyUnicode_FromId(&PyId_n_unnamed_fields) == NULL)

return -1;

return 0;

}

cpython/Objects/structseq.c at 3.5 · python/cpython · GitHub

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