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

   and posixmodule for example uses. */

#include "Python.h"

#include "structmember.h"

#include "structseq.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";

#define VISIBLE_SIZE(op) Py_SIZE(op)

#define VISIBLE_SIZE_TP(tp) PyInt_AsLong( \

                      PyDict_GetItemString((tp)->tp_dict, visible_length_key))

#define REAL_SIZE_TP(tp) PyInt_AsLong( \

                      PyDict_GetItemString((tp)->tp_dict, real_length_key))

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

#define UNNAMED_FIELDS_TP(tp) PyInt_AsLong( \

                      PyDict_GetItemString((tp)->tp_dict, unnamed_fields_key))

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

PyObject *

PyStructSequence_New(PyTypeObject *type)

{

	PyStructSequence *obj;

	obj = PyObject_New(PyStructSequence, type);

	if (obj == NULL)

		return NULL;

	Py_SIZE(obj) = VISIBLE_SIZE_TP(type);

	return (PyObject*) obj;

}

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_Del(obj);

}

static Py_ssize_t

structseq_length(PyStructSequence *obj)

{

	return VISIBLE_SIZE(obj);

}

static PyObject*

structseq_item(PyStructSequence *obj, Py_ssize_t i)

{

	if (i < 0 || i >= VISIBLE_SIZE(obj)) {

		PyErr_SetString(PyExc_IndexError, "tuple index out of range");

		return NULL;

	}

	Py_INCREF(obj->ob_item[i]);

	return obj->ob_item[i];

}

static PyObject*

structseq_slice(PyStructSequence *obj, Py_ssize_t low, Py_ssize_t high)

{

	PyTupleObject *np;

	Py_ssize_t i;

	if (low < 0)

		low = 0;

	if (high > VISIBLE_SIZE(obj))

		high = VISIBLE_SIZE(obj);

	if (high < low)

		high = low;

	np = (PyTupleObject *)PyTuple_New(high-low);

	if (np == NULL)

		return NULL;

	for(i = low; i < high; ++i) {

		PyObject *v = obj->ob_item[i];

		Py_INCREF(v);

		PyTuple_SET_ITEM(np, i-low, v);

	}

	return (PyObject *) np;

}

static PyObject *

structseq_subscript(PyStructSequence *self, PyObject *item)

{

	if (PyIndex_Check(item)) {

		Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);

		if (i == -1 && PyErr_Occurred())

			return NULL;

		if (i < 0)

			i += VISIBLE_SIZE(self);

		if (i < 0 || i >= VISIBLE_SIZE(self)) {

			PyErr_SetString(PyExc_IndexError,

				"tuple index out of range");

			return NULL;

		}

		Py_INCREF(self->ob_item[i]);

		return self->ob_item[i];

	}

	else if (PySlice_Check(item)) {

		Py_ssize_t start, stop, step, slicelen, cur, i;

		PyObject *result;

		if (PySlice_GetIndicesEx((PySliceObject *)item,

					 VISIBLE_SIZE(self), &start, &stop,

					 &step, &slicelen) < 0) {

			return NULL;

		}

		if (slicelen <= 0)

			return PyTuple_New(0);

		result = PyTuple_New(slicelen);

		if (result == NULL)

			return NULL;

		for (cur = start, i = 0; i < slicelen;

		     cur += step, i++) {

			PyObject *v = self->ob_item[cur];

			Py_INCREF(v);

			PyTuple_SET_ITEM(result, i, v);

		}

		return result;

	}

	else {

		PyErr_SetString(PyExc_TypeError,

				"structseq index must be integer");

		return NULL;

	}

}

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) {

		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 *

make_tuple(PyStructSequence *obj)

{

	return structseq_slice(obj, 0, VISIBLE_SIZE(obj));

}

static PyObject *

structseq_repr(PyStructSequence *obj)

{

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

#define REPR_BUFFER_SIZE 512

#define TYPE_MAXSIZE 100

	PyObject *tup;

	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];

	if ((tup = make_tuple(obj)) == NULL) {

		return NULL;

	}

	/* "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;

		val = PyTuple_GetItem(tup, i);

		if (cname == NULL || val == NULL) {

			return NULL;

		}

		repr = PyObject_Repr(val);

		if (repr == NULL) {

			Py_DECREF(tup);

			return NULL;

		}

		crepr = PyString_AsString(repr);

		if (crepr == NULL) {

			Py_DECREF(tup);

			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;

		}

	}

	Py_DECREF(tup);

	if (removelast) {

		/* overwrite last ", " */

		pbuf-=2;

	}

	*pbuf++ = ')';

	*pbuf = '\0';

	return PyString_FromString(buf);

}

static PyObject *

structseq_concat(PyStructSequence *obj, PyObject *b)

{

	PyObject *tup, *result;

	tup = make_tuple(obj);

	result = PySequence_Concat(tup, b);

	Py_DECREF(tup);

	return result;

}

static PyObject *

structseq_repeat(PyStructSequence *obj, Py_ssize_t n)

{

	PyObject *tup, *result;

	tup = make_tuple(obj);

	result = PySequence_Repeat(tup, n);

	Py_DECREF(tup);

	return result;

}

static int

structseq_contains(PyStructSequence *obj, PyObject *o)

{

	PyObject *tup;

	int result;

	tup = make_tuple(obj);

	if (!tup)

		return -1;

	result = PySequence_Contains(tup, o);

	Py_DECREF(tup);

	return result;

}

static long

structseq_hash(PyObject *obj)

{

	PyObject *tup;

	long result;

	tup = make_tuple((PyStructSequence*) obj);

	if (!tup)

		return -1;

	result = PyObject_Hash(tup);

	Py_DECREF(tup);

	return result;

}

static PyObject *

structseq_richcompare(PyObject *obj, PyObject *o2, int op)

{

	PyObject *tup, *result;

	tup = make_tuple((PyStructSequence*) obj);

	result = PyObject_RichCompare(tup, o2, op);

	Py_DECREF(tup);

	return result;

}

static PyObject *

structseq_reduce(PyStructSequence* self)

{

	PyObject* tup;

	PyObject* dict;

	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) {

		return NULL;

	}

	dict = PyDict_New();

	if (!dict) {

		Py_DECREF(tup);

		return NULL;

	}

	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;

		PyDict_SetItemString(dict, n,

				     self->ob_item[i]);

	}

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

	Py_DECREF(tup);

	Py_DECREF(dict);

	return result;

}

static PySequenceMethods structseq_as_sequence = {

	(lenfunc)structseq_length,

	(binaryfunc)structseq_concat,           /* sq_concat */

	(ssizeargfunc)structseq_repeat,         /* sq_repeat */

	(ssizeargfunc)structseq_item,		/* sq_item */

	(ssizessizeargfunc)structseq_slice,	/* sq_slice */

	0,					/* sq_ass_item */

	0,					/* sq_ass_slice */

	(objobjproc)structseq_contains,	        /* sq_contains */

};

static PyMappingMethods structseq_as_mapping = {

	(lenfunc)structseq_length,

	(binaryfunc)structseq_subscript,

};

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 */

        0,		                        /* tp_basicsize */

	0,	                      		/* tp_itemsize */

	(destructor)structseq_dealloc,	        /* tp_dealloc */

	0,                        	        /* tp_print */

	0,			 		/* tp_getattr */

	0,					/* tp_setattr */

	0,               			/* tp_compare */

	(reprfunc)structseq_repr,             	/* tp_repr */

	0,					/* tp_as_number */

	&structseq_as_sequence,			/* tp_as_sequence */

	&structseq_as_mapping,			/* tp_as_mapping */

	structseq_hash,				/* 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 */

	structseq_richcompare,			/* 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 */

};

void

PyStructSequence_InitType(PyTypeObject *type, PyStructSequence_Desc *desc)

{

	PyObject *dict;

	PyMemberDef* members;

	int n_members, n_unnamed_members, i, k;

#ifdef Py_TRACE_REFS

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

	   before overwriting its storage */

	if (type->_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_name = desc->name;

	type->tp_doc = desc->doc;

	type->tp_basicsize = sizeof(PyStructSequence)+

		sizeof(PyObject*)*(n_members-1);

	type->tp_itemsize = 0;

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

	if (members == NULL)

		return;

	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;

	Py_INCREF(type);

	dict = type->tp_dict;

#define SET_DICT_FROM_INT(key, value)				\

	do {							\

		PyObject *v = PyInt_FromLong((long) value);	\