Fix a bug in region_union_rect()

When region_union_rect() was called with a rect that was above the region without
intersecting it, the first band was created too large. This patch fixes this and
add a unitary test.

All credits go to @nfedera that:
* found the bug;
* find a dataset to reproduce;
* code the unitary test;
* spotted a suspicious line that was the faulty one.

diff --git a/libfreerdp/codec/region.c b/libfreerdp/codec/region.c
index e0bd384..be023b5 100644 (file)
--- a/libfreerdp/codec/region.c
+++ b/libfreerdp/codec/region.c
@@ -529,7 +529,7 @@ BOOL region16_union_rect(REGION16 *dst, const REGION16 *src, const RECTANGLE_16
                dstRect->top = rect->top;
                dstRect->left = rect->left;
                dstRect->right = rect->right;
-               dstRect->bottom = srcExtents->top;
+               dstRect->bottom = MIN(srcExtents->top, rect->bottom);
 
                usedRects++;
                dstRect++;

diff --git a/libfreerdp/codec/test/TestFreeRDPRegion.c b/libfreerdp/codec/test/TestFreeRDPRegion.c
index 8d6ca23..1694baa 100644 (file)
--- a/libfreerdp/codec/test/TestFreeRDPRegion.c
+++ b/libfreerdp/codec/test/TestFreeRDPRegion.c
@@ -689,6 +689,68 @@ out:
        return retCode;
 }
 
+static int test_norbert2_case() {
+       REGION16 region;
+       int retCode = -1;
+       const RECTANGLE_16 *rects;
+       int nbRects = 0;
+       int i;
+       RECTANGLE_16 rect1 = {  464, 696,   476,  709 };
+       RECTANGLE_16 rect2 = {    0,   0,  1024,   32 };
+
+       region16_init(&region);
+
+       if (!region16_union_rect(&region, &region, &rect1)) {
+               fprintf(stderr, "%s: Error 1 - region16_union_rect failed\n", __FUNCTION__);
+               goto out;
+       }
+
+       if (!(rects = region16_rects(&region, &nbRects))) {
+               fprintf(stderr, "%s: Error 2 - region16_rects failed\n", __FUNCTION__);
+               goto out;
+       }
+
+       if (nbRects != 1) {
+               fprintf(stderr, "%s: Error 3 - expected nbRects == 1 but got %d\n", __FUNCTION__, nbRects);
+               goto out;
+       }
+
+       if (!compareRectangles(&rects[0], &rect1, 1)) {
+               fprintf(stderr, "%s: Error 4 - compare failed\n", __FUNCTION__);
+               goto out;
+       }
+
+       if (!region16_union_rect(&region, &region, &rect2)) {
+               fprintf(stderr, "%s: Error 5 - region16_union_rect failed\n", __FUNCTION__);
+               goto out;
+       }
+
+       if (!(rects = region16_rects(&region, &nbRects))) {
+               fprintf(stderr, "%s: Error 6 - region16_rects failed\n", __FUNCTION__);
+               goto out;
+       }
+
+       if (nbRects != 2) {
+               fprintf(stderr, "%s: Error 7 - expected nbRects == 2 but got %d\n", __FUNCTION__, nbRects);
+               goto out;
+       }
+
+       if (!compareRectangles(&rects[0], &rect2, 1)) {
+               fprintf(stderr, "%s: Error 8 - compare failed\n", __FUNCTION__);
+               goto out;
+       }
+
+       if (!compareRectangles(&rects[1], &rect1, 1)) {
+               fprintf(stderr, "%s: Error 9 - compare failed\n", __FUNCTION__);
+               goto out;
+       }
+
+       retCode = 0;
+out:
+       region16_uninit(&region);
+       return retCode;
+}
+
 static int test_empty_rectangle() {
        REGION16 region, intersection;
        int retCode = -1;
@@ -765,7 +827,8 @@ struct UnitaryTest tests[] = {
        {"data from weston",        test_from_weston},
        {"R1 & R3",                                     test_r1_inter_r3},
        {"(R1+R3)&R11 (band merge)",test_r1_r3_inter_r11},
-       {"norbert case",                        test_norbert_case},
+       {"norbert's case",                      test_norbert_case},
+       {"norbert's case 2",            test_norbert2_case},
        {"empty rectangle case",        test_empty_rectangle},
 
        {NULL, NULL}