cpython/Objects/rangeobject.c

/***********************************************************
Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
The Netherlands.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
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distribution of the software without specific, written prior
permission.

While CWI is the initial source for this software, a modified version
is made available by the Corporation for National Research Initiatives
(CNRI) at the Internet address ftp://ftp.python.org.

STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
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PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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******************************************************************/

/* Range object implementation */

#include "allobjects.h"

typedef struct {
	OB_HEAD
	long	start;
	long	step;
	long	len;
	int	reps;
} rangeobject;


object *
newrangeobject(start, len, step, reps)
	long start, len, step;
	int reps;
{
	rangeobject *obj = NEWOBJ(rangeobject, &Rangetype);

	obj->start = start;
	obj->len   = len;
	obj->step  = step;
	obj->reps  = reps;

	return (object *) obj;
}

static void
range_dealloc(r)
	rangeobject *r;
{
	DEL(r);
}

static object *
range_item(r, i)
	rangeobject *r;
	int i;
{
	if (i < 0 || i >= r->len * r->reps) {
		err_setstr(IndexError, "range object index out of range");
		return NULL;
	}

	return newintobject(r->start + (i % r->len) * r->step);
}

static int
range_length(r)
	rangeobject *r;
{
	return r->len * r->reps;
}

static int
range_print(r, fp, flags)
	rangeobject *r;
	FILE *fp;
	int flags;
{
	int i, j;

	fprintf(fp, "(");
	for (i = 0; i < r->reps; ++i)
		for (j = 0; j < r->len; ++j) {
			if (j > 0 || i > 0)
				fprintf(fp, ", ");

			fprintf(fp, "%d", r->start + j * r->step);
		}

	if (r->len == 1 && r->reps == 1)
		fprintf(fp, ",");
	fprintf(fp, ")");
	return 0;
}

static object *
range_repr(r)
	rangeobject *r;
{
	char buf[80];
	sprintf(buf, "(xrange(%ld, %ld, %ld) * %d)",
			r->start,
			r->start + r->len * r->step,
			r->step,
			r->reps);
	return newstringobject(buf);
}

static object *
range_concat(r, obj)
	rangeobject *r;
	object *obj;
{
	err_setstr(TypeError, "cannot concatenate range objects");
	return NULL;
}

static object *
range_repeat(r, n)
	rangeobject *r;
	int n;
{
	if (n < 0)
		return (object *) newrangeobject(0, 0, 1, 1);

	else if (n == 1) {
		INCREF(r);
		return (object *) r;
	}

	else
		return (object *) newrangeobject(
						r->start,
						r->len,
						r->step,
						r->reps * n);
}

static int
range_compare(r1, r2)
	rangeobject *r1, *r2;
{
	if (r1->start != r2->start)
		return r1->start - r2->start;

	else if (r1->step != r2->step)
		return r1->step - r2->step;

	else if (r1->len != r2->len)
		return r1->len - r2->len;

	else
		return r1->reps - r2->reps;
}

static object *
range_slice(r, low, high)
	rangeobject *r;
	int low, high;
{
	if (r->reps != 1) {
		err_setstr(TypeError, "cannot slice a replicated range");
		return NULL;
	}
	if (low < 0)
		low = 0;
	else if (low > r->len)
		low = r->len;
	if (high < 0)
		high = 0;
	if (high < low)
		high = low;
	else if (high > r->len)
		high = r->len;

	if (low == 0 && high == r->len) {
		INCREF(r);
		return (object *) r;
	}

	return (object *) newrangeobject(
				low * r->step + r->start,
				high - low,
				r->step,
				1);
}

static object *
range_tolist(self, args)
rangeobject *self;
object *args;
{
	object *thelist;
	int j;
	int len = self->len * self->reps;

	if (! getargs(args, ""))
		return NULL;

	if ((thelist = newlistobject(len)) == NULL)
		return NULL;

	for (j = 0; j < len; ++j)
		if ((setlistitem(thelist, j,
					(object *) newintobject(
						self->start + (j % self->len) * self->step))) < 0)
			return NULL;

	return thelist;
}

static object *
range_getattr(r, name)
	rangeobject *r;
	char *name;
{
	static struct methodlist range_methods[] = {
		{"tolist",	(method)range_tolist},
		{NULL,		NULL}
	};

	return findmethod(range_methods, (object *) r, name);
}

static sequence_methods range_as_sequence = {
	(inquiry)range_length, /*sq_length*/
	(binaryfunc)range_concat, /*sq_concat*/
	(intargfunc)range_repeat, /*sq_repeat*/
	(intargfunc)range_item, /*sq_item*/
	(intintargfunc)range_slice, /*sq_slice*/
	0,		/*sq_ass_item*/
	0,		/*sq_ass_slice*/
};

typeobject Rangetype = {
	OB_HEAD_INIT(&Typetype)
	0,			/* Number of items for varobject */
	"xrange",		/* Name of this type */
	sizeof(rangeobject),	/* Basic object size */
	0,			/* Item size for varobject */
	(destructor)range_dealloc, /*tp_dealloc*/
	(printfunc)range_print, /*tp_print*/
	(getattrfunc)range_getattr, /*tp_getattr*/
	0,			/*tp_setattr*/
	(cmpfunc)range_compare, /*tp_compare*/
	(reprfunc)range_repr, /*tp_repr*/
	0,			/*tp_as_number*/
	&range_as_sequence,	/*tp_as_sequence*/
	0,			/*tp_as_mapping*/
};