FLANN uses much less RAM when decompressing saved index files. Should be backwards compatible with original index type.

Author: sprice

src/cpp/flann/algorithms/autotuned_index.h

@@ -208,17 +208,21 @@ class AutotunedIndex : public NNIndex<Distance>
 
     void saveIndex(FILE* stream)
     {
-    	serialization::SaveArchive sa(stream);
-    	sa & *this;
+        {
+            serialization::SaveArchive sa(stream);
+            sa & *this;
+        }
 
     	bestIndex_->saveIndex(stream);
     }
 
     void loadIndex(FILE* stream)
     {
-    	serialization::LoadArchive la(stream);
-    	la & *this;
-
+        {
+            serialization::LoadArchive la(stream);
+            la & *this;
+        }
+        
         IndexParams params;
         flann_algorithm_t index_type = get_param<flann_algorithm_t>(bestParams_,"algorithm");
         bestIndex_ = create_index_by_type<Distance>((flann_algorithm_t)index_type, dataset_, params, distance_);

src/cpp/flann/algorithms/nn_index.h

@@ -239,7 +239,7 @@ class NNIndex : public IndexBase
     	if (Archive::is_loading::value) {
             if (strncmp(header.h.signature,
                         FLANN_SIGNATURE_,
-                        strlen(FLANN_SIGNATURE_)) != 0) {
+                        strlen(FLANN_SIGNATURE_) - strlen("v0.0")) != 0) {
     	        throw FLANNException("Invalid index file, wrong signature");
     	    }
 

src/cpp/flann/util/saving.h

@@ -40,7 +40,7 @@
 #ifdef FLANN_SIGNATURE_
 #undef FLANN_SIGNATURE_
 #endif
-#define FLANN_SIGNATURE_ "FLANN_INDEX_v1.0"
+#define FLANN_SIGNATURE_ "FLANN_INDEX_v1.1"
 
 namespace flann
 {
@@ -60,7 +60,7 @@ struct IndexHeader
         strcpy(h.version, FLANN_VERSION_);
 
         h.compression = 0;
-        h.uncompressed_size = 0;
+        h.first_block_size = 0;
 	}
 
 private:
@@ -74,7 +74,7 @@ struct IndexHeader
         ar & h.rows;
         ar & h.cols;
         ar & h.compression;
-        ar & h.uncompressed_size;
+        ar & h.first_block_size;
     }
     friend struct serialization::access;
 };
@@ -114,7 +114,7 @@ inline IndexHeader load_header(FILE* stream)
 
     if (strncmp(header.h.signature,
                 FLANN_SIGNATURE_,
-                strlen(FLANN_SIGNATURE_)) != 0) {
+                strlen(FLANN_SIGNATURE_) - strlen("v0.0")) != 0) {
         throw FLANNException("Invalid index file, wrong signature");
     }