view src/test/serialize_tests.cpp @ 3640:195f5ad43476 draft

Compact serialization for variable-length integers Variable-length integers: bytes are a MSB base-128 encoding of the number. The high bit in each byte signifies whether another digit follows. To make the encoding is one-to-one, one is subtracted from all but the last digit. Thus, the byte sequence a[] with length len, where all but the last byte has bit 128 set, encodes the number: (a[len-1] & 0x7F) + sum(i=1..len-1, 128^i*((a[len-i-1] & 0x7F)+1)) Properties: * Very small (0-127: 1 byte, 128-16511: 2 bytes, 16512-2113663: 3 bytes) * Every integer has exactly one encoding * Encoding does not depend on size of original integer type
author Pieter Wuille <pieter.wuille@gmail.com>
date Fri, 15 Jun 2012 14:19:11 +0200
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#include <boost/test/unit_test.hpp>

#include <string>
#include <vector>

#include "serialize.h"

using namespace std;

BOOST_AUTO_TEST_SUITE(serialize_tests)

BOOST_AUTO_TEST_CASE(varints)
{
    // encode

    CDataStream ss(SER_DISK, 0);
    CDataStream::size_type size = 0;
    for (int i = 0; i < 100000; i++) {
        ss << VARINT(i);
        size += ::GetSerializeSize(VARINT(i), 0, 0);
        BOOST_CHECK(size == ss.size());
    }

    for (uint64 i = 0;  i < 100000000000ULL; i += 999999937) {
        ss << VARINT(i);
        size += ::GetSerializeSize(VARINT(i), 0, 0);
        BOOST_CHECK(size == ss.size());
    }

    // decode
    for (int i = 0; i < 100000; i++) {
        int j;
        ss >> VARINT(j);
        BOOST_CHECK_MESSAGE(i == j, "decoded:" << j << " expected:" << i);
    }

    for (uint64 i = 0;  i < 100000000000ULL; i += 999999937) {
        uint64 j;
        ss >> VARINT(j);
        BOOST_CHECK_MESSAGE(i == j, "decoded:" << j << " expected:" << i);
    }

}

BOOST_AUTO_TEST_SUITE_END()