Switch to boost memory-mapped file to save RAM and potentially improve performance.

src/libslic3r/Format/DRC.cpp

@@ -2,6 +2,8 @@
 #include <utility>
 #include <cstring>
 
+#include <boost/iostreams/device/mapped_file.hpp>
+
 #include <draco/compression/decode.h>
 #include <draco/io/mesh_io.h>
 #include <draco/mesh/mesh.h>
@@ -21,37 +23,25 @@ namespace Slic3r {
 
 bool load_drc(const char *path, TriangleMesh *meshptr)
 {
-    size_t size = boost::filesystem::file_size(path);
+    try {
-
+        boost::iostreams::mapped_file_source file(path);
-    FILE *fp = boost::nowide::fopen(path, "rb");
-    if (fp == nullptr) {
-        return false;
-    }
-
-    char *data = new char[size];
-    if (fread(data, 1, size, fp) != size) {
-        fclose(fp);
-        delete[] data;
-        return false;
-    }
-    fclose(fp);
         
         DecoderBuffer buffer;
-    buffer.Init(data, size);
+        buffer.Init(file.data(), file.size());        
 
         auto geotype = Decoder::GetEncodedGeometryType(&buffer);
         if ((!geotype.ok()) || geotype.value() != TRIANGULAR_MESH) {
-        delete[] data;
             return false;
         }
         
         Decoder decoder;
         Mesh dracoMesh;
         Status status = decoder.DecodeBufferToGeometry(&buffer, &dracoMesh);
-    delete[] data;
         if (!status.ok()) {
             return false;
         }
+        file.close();
+        
         
         indexed_triangle_set its;
         
@@ -79,6 +69,10 @@ bool load_drc(const char *path, TriangleMesh *meshptr)
         *meshptr = TriangleMesh(std::move(its));
         if (meshptr->volume() < 0)
             meshptr->flip_triangles();
+    } catch (const std::exception& e) {
+        BOOST_LOG_TRIVIAL(error) << "load_drc: " << e.what();
+        return false;
+    }
     return true;
 }