From 84cc7032e65affdc2bc883228fa651986fb62509 Mon Sep 17 00:00:00 2001
From: Andrew Bell <andrew.bell.ia@gmail.com>
Date: Fri, 22 Jan 2021 08:56:19 -0500
Subject: [PATCH] Support LAS start

---
 epf/Epf.cpp           | 32 +++++++++++++++++++++++++++++++-
 epf/EpfTypes.hpp      |  4 ++++
 epf/FileProcessor.cpp |  7 +++++++
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/epf/Epf.cpp b/epf/Epf.cpp
index d54ecfd..033ba7f 100644
--- a/epf/Epf.cpp
+++ b/epf/Epf.cpp
@@ -20,6 +20,7 @@
 
 #include <unordered_set>
 
+#include <pdal/pdal_features.hpp>
 #include <pdal/Dimension.hpp>
 #include <pdal/PointLayout.hpp>
 #include <pdal/StageFactory.hpp>
@@ -185,6 +186,7 @@ PointCount Epf::createFileInfo(const StringList& input, StringList dimNames,
 {
     using namespace pdal;
 
+    std::vector<FileInfo> tempFileInfos;
     std::vector<std::string> filenames;
     PointCount totalPoints = 0;
 
@@ -247,13 +249,41 @@ PointCount Epf::createFileInfo(const StringList& input, StringList dimNames,
             std::cerr << "Files have mismatched SRS values. Using SRS from '" <<
                 m_srsFileInfo.filename << "'.\n";
         fi.srs = qi.m_srs;
-        fileInfos.push_back(fi);
+        tempFileInfos.push_back(fi);
         if (!m_srsFileInfo.valid() && qi.m_srs.valid())
             m_srsFileInfo = fi;
 
         m_grid.expand(qi.m_bounds, qi.m_pointCount);
         totalPoints += fi.numPoints;
     }
+
+
+#ifdef PDAL_LAS_START
+    PointCount ChunkSize = 5000000;
+    for (const FileInfo& fi : tempFileInfos)
+    {
+        if (fi.driver != "readers.las" || fi.numPoints < ChunkSize)
+        {
+            fileInfos.push_back(fi);
+            continue;
+        }
+        PointCount remaining = fi.numPoints;
+        pdal::PointId start = 0;
+        while (remaining)
+        {
+            FileInfo lasFi(fi);
+            lasFi.numPoints = (std::min)(ChunkSize, remaining);
+            lasFi.start = start;
+            fileInfos.push_back(lasFi);
+
+            start += ChunkSize;
+            remaining -= lasFi.numPoints;
+        }
+    }
+#else
+    fileInfos = std::move(tempFileInfos);
+#endif
+
     return totalPoints;
 }
 
diff --git a/epf/EpfTypes.hpp b/epf/EpfTypes.hpp
index f0740e6..895d6e8 100644
--- a/epf/EpfTypes.hpp
+++ b/epf/EpfTypes.hpp
@@ -41,10 +41,14 @@ constexpr int NumFileProcessors = 8;
 
 struct FileInfo
 {
+    FileInfo() : numPoints(0), start(0)
+    {}
+
     std::string filename;
     std::string driver;
     DimInfoList dimInfo;
     uint64_t numPoints;
+    uint64_t start;
     pdal::BOX3D bounds;
     pdal::SpatialReference srs;
 
diff --git a/epf/FileProcessor.cpp b/epf/FileProcessor.cpp
index 07e498b..f02faa4 100644
--- a/epf/FileProcessor.cpp
+++ b/epf/FileProcessor.cpp
@@ -14,6 +14,7 @@
 #include "FileProcessor.hpp"
 #include "../untwine/ProgressWriter.hpp"
 
+#include <pdal/pdal_features.hpp>
 #include <pdal/StageFactory.hpp>
 #include <pdal/filters/StreamCallbackFilter.hpp>
 
@@ -29,8 +30,14 @@ FileProcessor::FileProcessor(const FileInfo& fi, size_t pointSize, const Grid& g
 
 void FileProcessor::run()
 {
+
     pdal::Options opts;
     opts.add("filename", m_fi.filename);
+    opts.add("count", m_fi.numPoints);
+#ifdef PDAL_LAS_START
+    if (m_fi.driver == "readers.las")
+        opts.add("start", m_fi.start);
+#endif
 
     pdal::StageFactory factory;
     pdal::Stage *s = factory.createStage(m_fi.driver);