// SPDX-License-Identifier: GPL-2.0
/*
 * Test cases for the drm_rect functions
 *
 * Copyright (c) 2022 Maíra Canal <mairacanal@riseup.net>
 */

#include <kunit/test.h>

#include <drm/drm_rect.h>

static void drm_test_rect_clip_scaled_div_by_zero(struct kunit *test)
{
	struct drm_rect src, dst, clip;
	bool visible;

	/*
	 * Make sure we don't divide by zero when dst
	 * width/height is zero and dst and clip do not intersect.
	 */
	drm_rect_init(&src, 0, 0, 0, 0);
	drm_rect_init(&dst, 0, 0, 0, 0);
	drm_rect_init(&clip, 1, 1, 1, 1);
	visible = drm_rect_clip_scaled(&src, &dst, &clip);

	KUNIT_EXPECT_FALSE_MSG(test, visible, "Destination not be visible\n");
	KUNIT_EXPECT_FALSE_MSG(test, drm_rect_visible(&src), "Source should not be visible\n");

	drm_rect_init(&src, 0, 0, 0, 0);
	drm_rect_init(&dst, 3, 3, 0, 0);
	drm_rect_init(&clip, 1, 1, 1, 1);
	visible = drm_rect_clip_scaled(&src, &dst, &clip);

	KUNIT_EXPECT_FALSE_MSG(test, visible, "Destination not be visible\n");
	KUNIT_EXPECT_FALSE_MSG(test, drm_rect_visible(&src), "Source should not be visible\n");
}

static void drm_test_rect_clip_scaled_not_clipped(struct kunit *test)
{
	struct drm_rect src, dst, clip;
	bool visible;

	/* 1:1 scaling */
	drm_rect_init(&src, 0, 0, 1 << 16, 1 << 16);
	drm_rect_init(&dst, 0, 0, 1, 1);
	drm_rect_init(&clip, 0, 0, 1, 1);

	visible = drm_rect_clip_scaled(&src, &dst, &clip);

	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 0 || src.x2 != 1 << 16 ||
			       src.y1 != 0 || src.y2 != 1 << 16, "Source badly clipped\n");
	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 0 || dst.x2 != 1 ||
			       dst.y1 != 0 || dst.y2 != 1, "Destination badly clipped\n");
	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");

	/* 2:1 scaling */
	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
	drm_rect_init(&dst, 0, 0, 1, 1);
	drm_rect_init(&clip, 0, 0, 1, 1);

	visible = drm_rect_clip_scaled(&src, &dst, &clip);

	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 0 || src.x2 != 2 << 16 ||
			       src.y1 != 0 || src.y2 != 2 << 16, "Source badly clipped\n");
	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 0 || dst.x2 != 1 ||
			       dst.y1 != 0 || dst.y2 != 1, "Destination badly clipped\n");
	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");

	/* 1:2 scaling */
	drm_rect_init(&src, 0, 0, 1 << 16, 1 << 16);
	drm_rect_init(&dst, 0, 0, 2, 2);
	drm_rect_init(&clip, 0, 0, 2, 2);

	visible = drm_rect_clip_scaled(&src, &dst, &clip);

	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 0 || src.x2 != 1 << 16 ||
			       src.y1 != 0 || src.y2 != 1 << 16, "Source badly clipped\n");
	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 0 || dst.x2 != 2 ||
			       dst.y1 != 0 || dst.y2 != 2, "Destination badly clipped\n");
	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");
}

static void drm_test_rect_clip_scaled_clipped(struct kunit *test)
{
	struct drm_rect src, dst, clip;
	bool visible;

	/* 1:1 scaling top/left clip */
	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
	drm_rect_init(&dst, 0, 0, 2, 2);
	drm_rect_init(&clip, 0, 0, 1, 1);

	visible = drm_rect_clip_scaled(&src, &dst, &clip);

	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 0 || src.x2 != 1 << 16 ||
			       src.y1 != 0 || src.y2 != 1 << 16, "Source badly clipped\n");
	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 0 || dst.x2 != 1 ||
			       dst.y1 != 0 || dst.y2 != 1, "Destination badly clipped\n");
	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");

	/* 1:1 scaling bottom/right clip */
	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
	drm_rect_init(&dst, 0, 0, 2, 2);
	drm_rect_init(&clip, 1, 1, 1, 1);

	visible = drm_rect_clip_scaled(&src, &dst, &clip);

	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 1 << 16 || src.x2 != 2 << 16 ||
			       src.y1 != 1 << 16 || src.y2 != 2 << 16, "Source badly clipped\n");
	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 1 || dst.x2 != 2 || dst.y1 != 1 ||
			       dst.y2 != 2, "Destination badly clipped\n");
	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");

	/* 2:1 scaling top/left clip */
	drm_rect_init(&src, 0, 0, 4 << 16, 4 << 16);
	drm_rect_init(&dst, 0, 0, 2, 2);
	drm_rect_init(&clip, 0, 0, 1, 1);

	visible = drm_rect_clip_scaled(&src, &dst, &clip);

	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 0 || src.x2 != 2 << 16 ||
			       src.y1 != 0 || src.y2 != 2 << 16, "Source badly clipped\n");
	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 0 || dst.x2 != 1 || dst.y1 != 0 ||
			       dst.y2 != 1, "Destination badly clipped\n");
	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");

	/* 2:1 scaling bottom/right clip */
	drm_rect_init(&src, 0, 0, 4 << 16, 4 << 16);
	drm_rect_init(&dst, 0, 0, 2, 2);
	drm_rect_init(&clip, 1, 1, 1, 1);

	visible = drm_rect_clip_scaled(&src, &dst, &clip);

	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 2 << 16 || src.x2 != 4 << 16 ||
			       src.y1 != 2 << 16 || src.y2 != 4 << 16, "Source badly clipped\n");
	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 1 || dst.x2 != 2 || dst.y1 != 1 ||
			       dst.y2 != 2, "Destination badly clipped\n");
	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");

	/* 1:2 scaling top/left clip */
	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
	drm_rect_init(&dst, 0, 0, 4, 4);
	drm_rect_init(&clip, 0, 0, 2, 2);

	visible = drm_rect_clip_scaled(&src, &dst, &clip);

	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 0 || src.x2 != 1 << 16 ||
			       src.y1 != 0 || src.y2 != 1 << 16, "Source badly clipped\n");
	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 0 || dst.x2 != 2 || dst.y1 != 0 ||
			       dst.y2 != 2, "Destination badly clipped\n");
	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");

	/* 1:2 scaling bottom/right clip */
	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
	drm_rect_init(&dst, 0, 0, 4, 4);
	drm_rect_init(&clip, 2, 2, 2, 2);

	visible = drm_rect_clip_scaled(&src, &dst, &clip);

	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 1 << 16 || src.x2 != 2 << 16 ||
			       src.y1 != 1 << 16 || src.y2 != 2 << 16, "Source badly clipped\n");
	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 2 || dst.x2 != 4 || dst.y1 != 2 ||
			       dst.y2 != 4, "Destination badly clipped\n");
	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");
}

static void drm_test_rect_clip_scaled_signed_vs_unsigned(struct kunit *test)
{
	struct drm_rect src, dst, clip;
	bool visible;

	/*
	 * 'clip.x2 - dst.x1 >= dst width' could result a negative
	 * src rectangle width which is no longer expected by the
	 * code as it's using unsigned types. This could lead to
	 * the clipped source rectangle appering visible when it
	 * should have been fully clipped. Make sure both rectangles
	 * end up invisible.
	 */
	drm_rect_init(&src, 0, 0, INT_MAX, INT_MAX);
	drm_rect_init(&dst, 0, 0, 2, 2);
	drm_rect_init(&clip, 3, 3, 1, 1);

	visible = drm_rect_clip_scaled(&src, &dst, &clip);

	KUNIT_EXPECT_FALSE_MSG(test, visible, "Destination should not be visible\n");
	KUNIT_EXPECT_FALSE_MSG(test, drm_rect_visible(&src), "Source should not be visible\n");
}

static struct kunit_case drm_rect_tests[] = {
	KUNIT_CASE(drm_test_rect_clip_scaled_div_by_zero),
	KUNIT_CASE(drm_test_rect_clip_scaled_not_clipped),
	KUNIT_CASE(drm_test_rect_clip_scaled_clipped),
	KUNIT_CASE(drm_test_rect_clip_scaled_signed_vs_unsigned),
	{ }
};

static struct kunit_suite drm_rect_test_suite = {
	.name = "drm_rect",
	.test_cases = drm_rect_tests,
};

kunit_test_suite(drm_rect_test_suite);

MODULE_LICENSE("GPL");