add check for .enc extension to support encryption (#467)

* add check for .enc extension to support encryption

* check rotation_matrix file in file blobs

include/utils.h

@@ -57,7 +57,7 @@ typedef int FileHandle;
 #define PBSTR "||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||"
 #define PBWIDTH 60
 
-inline bool file_exists(const std::string &name, bool dirCheck = false)
+inline bool file_exists_impl(const std::string &name, bool dirCheck = false)
 {
     int val;
 #ifndef _WINDOWS
@@ -94,6 +94,29 @@ inline bool file_exists(const std::string &name, bool dirCheck = false)
     }
 }
 
+inline bool file_exists(const std::string &name, bool dirCheck = false)
+{
+#ifdef EXEC_ENV_OLS
+    bool exists = file_exists_impl(name, dirCheck);
+    if (exists)
+    {
+        return true;
+    }
+    if (!dirCheck)
+    {
+        // try with .enc extension
+        std::string enc_name = name + ENCRYPTED_EXTENSION;
+        return file_exists_impl(enc_name, dirCheck);
+    }
+    else
+    {
+        return exists;
+    }
+#else
+    return file_exists_impl(name, dirCheck);
+#endif
+}
+
 inline void open_file_to_write(std::ofstream &writer, const std::string &filename)
 {
     writer.exceptions(std::ofstream::failbit | std::ofstream::badbit);

src/pq.cpp

@@ -133,11 +133,13 @@ void FixedChunkPQTable::load_pq_centroid_bin(const char *pq_table_file, size_t n
     diskann::cout << "Loaded PQ Pivots: #ctrs: " << NUM_PQ_CENTROIDS << ", #dims: " << this->ndims
                   << ", #chunks: " << this->n_chunks << std::endl;
 
-    if (file_exists(rotmat_file))
-    {
 #ifdef EXEC_ENV_OLS
+    if (files.fileExists(rotmat_file))
+    {
         diskann::load_bin<float>(files, rotmat_file, (float *&)rotmat_tr, nr, nc);
 #else
+    if (file_exists(rotmat_file))
+    {
         diskann::load_bin<float>(rotmat_file, rotmat_tr, nr, nc);
 #endif
         if (nr != this->ndims || nc != this->ndims)