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Add protection against stack overflow when flood-filling.

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This commit is contained in:
Daniel Beer 2012-11-13 10:45:55 +13:00
parent b7a6827b54
commit bdbd932b72
1 changed files with 14 additions and 8 deletions
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22
lib/identify.c
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@ -121,16 +121,22 @@ static void perspective_unmap(const double *c,
* Span-based floodfill routine * Span-based floodfill routine
*/ */
#define FLOOD_FILL_MAX_DEPTH 4096
typedef void (*span_func_t)(void *user_data, int y, int left, int right); typedef void (*span_func_t)(void *user_data, int y, int left, int right);
static void flood_fill_seed(struct quirc *q, int x, int y, int from, int to, static void flood_fill_seed(struct quirc *q, int x, int y, int from, int to,
span_func_t func, void *user_data) span_func_t func, void *user_data,
int depth)
{ {
int left = x; int left = x;
int right = x; int right = x;
int i; int i;
uint8_t *row = q->image + y * q->w; uint8_t *row = q->image + y * q->w;
if (depth >= FLOOD_FILL_MAX_DEPTH)
return;
while (left > 0 && row[left - 1] == from) while (left > 0 && row[left - 1] == from)
left--; left--;
@ -151,7 +157,7 @@ static void flood_fill_seed(struct quirc *q, int x, int y, int from, int to,
for (i = left; i <= right; i++) for (i = left; i <= right; i++)
if (row[i] == from) if (row[i] == from)
flood_fill_seed(q, i, y - 1, from, to, flood_fill_seed(q, i, y - 1, from, to,
func, user_data); func, user_data, depth + 1);
} }
if (y < q->h - 1) { if (y < q->h - 1) {
@ -160,7 +166,7 @@ static void flood_fill_seed(struct quirc *q, int x, int y, int from, int to,
for (i = left; i <= right; i++) for (i = left; i <= right; i++)
if (row[i] == from) if (row[i] == from)
flood_fill_seed(q, i, y + 1, from, to, flood_fill_seed(q, i, y + 1, from, to,
func, user_data); func, user_data, depth + 1);
} }
} }
@ -250,7 +256,7 @@ static int region_code(struct quirc *q, int x, int y)
box->seed.y = y; box->seed.y = y;
box->capstone = -1; box->capstone = -1;
flood_fill_seed(q, x, y, pixel, region, area_count, box); flood_fill_seed(q, x, y, pixel, region, area_count, box, 0);
return region; return region;
} }
@ -320,7 +326,7 @@ static void find_region_corners(struct quirc *q,
psd.scores[0] = -1; psd.scores[0] = -1;
flood_fill_seed(q, region->seed.x, region->seed.y, flood_fill_seed(q, region->seed.x, region->seed.y,
rcode, QUIRC_PIXEL_BLACK, rcode, QUIRC_PIXEL_BLACK,
find_one_corner, &psd); find_one_corner, &psd, 0);
psd.ref.x = psd.corners[0].x - psd.ref.x; psd.ref.x = psd.corners[0].x - psd.ref.x;
psd.ref.y = psd.corners[0].y - psd.ref.y; psd.ref.y = psd.corners[0].y - psd.ref.y;
@ -338,7 +344,7 @@ static void find_region_corners(struct quirc *q,
flood_fill_seed(q, region->seed.x, region->seed.y, flood_fill_seed(q, region->seed.x, region->seed.y,
QUIRC_PIXEL_BLACK, rcode, QUIRC_PIXEL_BLACK, rcode,
find_other_corners, &psd); find_other_corners, &psd, 0);
} }
static void record_capstone(struct quirc *q, int ring, int stone) static void record_capstone(struct quirc *q, int ring, int stone)
@ -951,10 +957,10 @@ static void record_qr_grid(struct quirc *q, int a, int b, int c)
flood_fill_seed(q, reg->seed.x, reg->seed.y, flood_fill_seed(q, reg->seed.x, reg->seed.y,
qr->align_region, QUIRC_PIXEL_BLACK, qr->align_region, QUIRC_PIXEL_BLACK,
NULL, NULL); NULL, NULL, 0);
flood_fill_seed(q, reg->seed.x, reg->seed.y, flood_fill_seed(q, reg->seed.x, reg->seed.y,
QUIRC_PIXEL_BLACK, qr->align_region, QUIRC_PIXEL_BLACK, qr->align_region,
find_leftmost_to_line, &psd); find_leftmost_to_line, &psd, 0);
} }
} }