boost serialisation file size comparison
I have written some test for the different kind of serialization archives in my application. In the test below the only difference is the kind of archive used ( and use of ios::binary for the binary streams) ANode:: ...test_node_tree_persistence_text file_size: 4014 ANode:: ...test_node_tree_persistence_binary file_size: 5351 ANode:: ...test_node_tree_persistence_portable_binary file_size: 2878 What I don't understand is why should the binary archive serialization file size be larger than text ? -- Best regards, Ta, Avi
Hello Avi, let's consider the following case: we want to serialize the following 'small' integers: 0 1 2 3 4 5 in ASCII text archive, you get the following readable string: "0 1 2 3 4 5" this is 11 chars (6 digits + 5 white space) == 11 bytes in binary, if you use 32 bits integers (int on typical processor): you get (typically) the following string of 6 ints x 4 bytes == 24 bytes (no need for white space separator in this case). this is about twice the ASCII storage. this example shows a special case when the situation you mention could occur. it depends on your data. anyway generally, it is more efficient to store in binary. If you try to compress (gz or whatever) both archives, I expect the sizes of the files to be comparable, because the basic information contents is the same. A good approach to save storage room would be to use int16_t or even int8_t types if it's enough to suit your needs. hope it helps regards frc --
Avi Bahra a écrit : I have written some test for the different kind of serialization archives in my application. In the test below the only difference is the kind of archive used ( and use of ios::binary for the binary streams)
ANode:: ...test_node_tree_persistence_text file_size: 4014 ANode:: ...test_node_tree_persistence_binary file_size: 5351 ANode:: ...test_node_tree_persistence_portable_binary file_size: 2878
What I don't understand is why should the binary archive serialization file size be larger than text ?
-- Best regards, Ta, Avi
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-- François Mauger Département de Physique - Université de Caen Basse-Normandie courriel/e-mail: mauger@lpccaen.in2p3.fr tél./phone: 02 31 45 25 12 / (+33) 2 31 45 25 12 fax: 02 31 45 25 49 / (+33) 2 31 45 25 49 Adresse/address: Laboratoire de Physique Corpusculaire de Caen (UMR 6534) ENSICAEN 6, Boulevard du Marechal Juin 14050 CAEN Cedex FRANCE
Avi Bahra wrote:
I have written some test for the different kind of serialization archives in my application. In the test below the only difference is the kind of archive used ( and use of ios::binary for the binary streams)
ANode:: ...test_node_tree_persistence_text file_size: 4014 ANode:: ...test_node_tree_persistence_binary file_size: 5351 ANode:: ...test_node_tree_persistence_portable_binary file_size: 2878
What I don't understand is why should the binary archive serialization file size be larger than text ?
Binary storage of a 32 bit int requires 32 bits even if the value is zero, whereas a zero in text(ascii) representation takes a byte for the 0 char and a byte for the separating space char. Jeff
participants (3)
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Avi Bahra -
Francois Mauger -
Jeff Flinn