1 files changed, 117 insertions, 0 deletions
diff --git a/extern/libmv/third_party/fast/nonmax.c b/extern/libmv/third_party/fast/nonmax.c
new file mode 100644
index 00000000000..6ed0f580906
--- /dev/null
+++ b/extern/libmv/third_party/fast/nonmax.c
@@ -0,0 +1,117 @@
+#include <stdlib.h>
+#include "fast.h"
+
+
+#define Compare(X, Y) ((X)>=(Y))
+
+xy* nonmax_suppression(const xy* corners, const int* scores, int num_corners, int* ret_num_nonmax)
+{
+	int num_nonmax=0;
+	int last_row;
+	int* row_start;
+	int i, j;
+	xy* ret_nonmax;
+	const int sz = (int)num_corners; 
+
+	/*Point above points (roughly) to the pixel above the one of interest, if there
+    is a feature there.*/
+	int point_above = 0;
+	int point_below = 0;
+
+	
+	if(num_corners < 1)
+	{
+		*ret_num_nonmax = 0;
+		return 0;
+	}
+
+	ret_nonmax = (xy*)malloc(num_corners * sizeof(xy));
+
+	/* Find where each row begins
+	   (the corners are output in raster scan order). A beginning of -1 signifies
+	   that there are no corners on that row. */
+	last_row = corners[num_corners-1].y;
+	row_start = (int*)malloc((last_row+1)*sizeof(int));
+
+	for(i=0; i < last_row+1; i++)
+		row_start[i] = -1;
+	
+	{
+		int prev_row = -1;
+		for(i=0; i< num_corners; i++)
+			if(corners[i].y != prev_row)
+			{
+				row_start[corners[i].y] = i;
+				prev_row = corners[i].y;
+			}
+	}
+	
+	
+	
+	for(i=0; i < sz; i++)
+	{
+		int score = scores[i];
+		xy pos = corners[i];
+			
+		/*Check left */
+		if(i > 0)
+			if(corners[i-1].x == pos.x-1 && corners[i-1].y == pos.y && Compare(scores[i-1], score))
+				continue;
+			
+		/*Check right*/
+		if(i < (sz - 1))
+			if(corners[i+1].x == pos.x+1 && corners[i+1].y == pos.y && Compare(scores[i+1], score))
+				continue;
+			
+		/*Check above (if there is a valid row above)*/
+		if(pos.y != 0 && row_start[pos.y - 1] != -1) 
+		{
+			/*Make sure that current point_above is one
+			  row above.*/
+			if(corners[point_above].y < pos.y - 1)
+				point_above = row_start[pos.y-1];
+			
+			/*Make point_above point to the first of the pixels above the current point,
+			  if it exists.*/
+			for(; corners[point_above].y < pos.y && corners[point_above].x < pos.x - 1; point_above++)
+			{}
+			
+			
+			for(j=point_above; corners[j].y < pos.y && corners[j].x <= pos.x + 1; j++)
+			{
+				int x = corners[j].x;
+				if( (x == pos.x - 1 || x ==pos.x || x == pos.x+1) && Compare(scores[j], score))
+					goto cont;
+			}
+			
+		}
+			
+		/*Check below (if there is anything below)*/
+		if(pos.y != last_row && row_start[pos.y + 1] != -1 && point_below < sz) /*Nothing below*/
+		{
+			if(corners[point_below].y < pos.y + 1)
+				point_below = row_start[pos.y+1];
+			
+			/* Make point below point to one of the pixels belowthe current point, if it
+			   exists.*/
+			for(; point_below < sz && corners[point_below].y == pos.y+1 && corners[point_below].x < pos.x - 1; point_below++)
+			{}
+
+			for(j=point_below; j < sz && corners[j].y == pos.y+1 && corners[j].x <= pos.x + 1; j++)
+			{
+				int x = corners[j].x;
+				if( (x == pos.x - 1 || x ==pos.x || x == pos.x+1) && Compare(scores[j],score))
+					goto cont;
+			}
+		}
+		
+		ret_nonmax[num_nonmax++] = corners[i];
+		cont:
+			;
+	}
+
+	free(row_start);
+	*ret_num_nonmax = num_nonmax;
+	return ret_nonmax;
+}
+