improve data file loading performance

Author: Sanhaoji2

include/utils.h

@@ -986,10 +986,17 @@ inline void copy_aligned_data_from_file(const char *bin_file, T *&data, size_t &
     npts = (unsigned)npts_i32;
     dim = (unsigned)dim_i32;
 
-    for (size_t i = 0; i < npts; i++)
+    if (rounded_dim != dim)
     {
-        reader.read((char *)(data + i * rounded_dim), dim * sizeof(T));
-        memset(data + i * rounded_dim + dim, 0, (rounded_dim - dim) * sizeof(T));
+        for (size_t i = 0; i < npts; i++)
+        {
+            reader.read((char*)(data + i * rounded_dim), dim * sizeof(T));
+            memset(data + i * rounded_dim + dim, 0, (rounded_dim - dim) * sizeof(T));
+        }
+    }
+    else
+    {
+        reader.read((char *)data, npts * dim * sizeof(T));
     }
 }
 

src/in_mem_static_graph_reformat.cpp

@@ -12,11 +12,12 @@ std::tuple<uint32_t, uint32_t, size_t> InMemStaticGraphReformatStore::load_impl(
     size_t num_points;
     size_t file_offset = 0; // will need this for single file format support
 
-    size_t check_file_size = get_file_size(filename);
-
     std::ifstream in;
     in.exceptions(std::ios::badbit | std::ios::failbit);
     in.open(filename, std::ios::binary);
+    // get file size
+    size_t check_file_size = in.tellg();
+    
     in.seekg(file_offset, in.beg);
     in.read((char*)&expected_file_size, sizeof(size_t));
     in.read((char*)&_max_observed_degree, sizeof(uint32_t));