Handle the case that too many points were requested in head and tail …

…filter
PDAL · Jun 12, 2017 · ad6a625 · ad6a625
1 parent 60f1949
commit ad6a625
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Showing 4 changed files with 22 additions and 3 deletions.
diff --git a/doc/stages/filters.head.rst b/doc/stages/filters.head.rst
@@ -6,6 +6,11 @@ filters.head
 The HeadFilter returns a specified number of points from the beginning of the
 PointView.
 
+.. note::
+
+    If the requested number of points exceeds the size of the point cloud, all
+    points are passed with a warning.
+
 
 Example #1
 ----------

diff --git a/doc/stages/filters.tail.rst b/doc/stages/filters.tail.rst
@@ -6,6 +6,11 @@ filters.tail
 The TailFilter returns a specified number of points from the end of the
 PointView.
 
+.. note::
+
+    If the requested number of points exceeds the size of the point cloud, all
+    points are passed with a warning.
+
 
 Example #1
 ----------
@@ -28,7 +33,7 @@ Sort and extract the 100 lowest intensity points.
         }
       ]
     }
-    
+
 
 .. seealso::
 

diff --git a/filters/HeadFilter.hpp b/filters/HeadFilter.hpp
@@ -66,9 +66,13 @@ class PDAL_DLL HeadFilter : public Filter
 
     PointViewSet run(PointViewPtr view)
     {
+        if (m_count > view->size())
+            log()->get(LogLevel::Warning)
+                << "Requested number of points (count=" << m_count
+                << ") exceeds number of available points.\n";
         PointViewSet viewSet;
         PointViewPtr outView = view->makeNew();
-        for (PointId i = 0; i < m_count; ++i)
+        for (PointId i = 0; i < std::min(m_count, view->size()); ++i)
             outView->appendPoint(*view, i);
         viewSet.insert(outView);
         return viewSet;

diff --git a/filters/TailFilter.hpp b/filters/TailFilter.hpp
@@ -66,9 +66,14 @@ class PDAL_DLL TailFilter : public Filter
 
     PointViewSet run(PointViewPtr view)
     {
+        if (m_count > view->size())
+            log()->get(LogLevel::Warning)
+                << "Requested number of points (count=" << m_count
+                << ") exceeds number of available points.\n";
         PointViewSet viewSet;
         PointViewPtr outView = view->makeNew();
-        for (PointId i = view->size() - m_count; i < view->size(); ++i)
+        for (PointId i = view->size() - std::min(m_count, view->size());
+             i < view->size(); ++i)
             outView->appendPoint(*view, i);
         viewSet.insert(outView);
         return viewSet;