db_get_i64 now supports buffer_size = 0

libraries/chain/apply_context.cpp

@@ -421,7 +421,6 @@ int apply_context::get_context_free_data( uint32_t index, char* buffer, size_t b
    if( index >= trx_meta.context_free_data.size() ) return -1;
 
    auto s = trx_meta.context_free_data[index].size();
-
    if( buffer_size == 0 ) return s;
 
    auto copy_size = std::min( buffer_size, s );
@@ -523,9 +522,14 @@ void apply_context::db_remove_i64( int iterator ) {
 
 int apply_context::db_get_i64( int iterator, char* buffer, size_t buffer_size ) {
    const key_value_object& obj = keyval_cache.get( iterator );
-   memcpy( buffer, obj.value.data(), std::min(obj.value.size(), buffer_size) );
 
-   return obj.value.size();
+   auto s = obj.value.size();
+   if( buffer_size == 0 ) return s;
+
+   auto copy_size = std::min( buffer_size, s );
+   memcpy( buffer, obj.value.data(), copy_size );
+
+   return copy_size;
 }
 
 int apply_context::db_next_i64( int iterator, uint64_t& primary ) {