adler32.cc

Go to the documentation of this file.

#include <encode/adler32.h>
#include <crypto/random.h>
#include <gtest/gtest.h>
#include <iostream>
#include <string>
#include <fstream>
 
using namespace std;
using scc::encode::Adler32;
 
static string test =
"ljpoaweu9uwat7a9g0ujaW219U0U;DSJGEOPUJGAfPVAPUAS:FGJALGJ7804-85,"      // 64 bytes
"G;AKGPTG[ASIGSFDAS[DFSAPDFJASPFJSPADFJPAJPGAJSGSAGJAPJGAPJGPOIOO";     // 64 bytes
static uint32_t all_ad = 0xf9932612;        // all bytes
static uint32_t last64_ad = 0x583e1280;     // last 64 bytes
 
TEST(adler32, construct)
{
    Adler32 ad;
    ASSERT_EQ(ad.val(), 1);
    ASSERT_EQ(ad.size(), 0);
 
    Adler32 ad2(test.data(), test.size());
    ASSERT_EQ(ad2.val(), all_ad);
    ASSERT_EQ(ad2.size(), test.size());
}
 
TEST(adler32, single_update)
{
    Adler32 ad;
    ad.update(test.data(), test.size());
    ASSERT_EQ(ad.val(), all_ad);
}
 
TEST(adler32, two_updates)
{
    Adler32 ad;
    ad.update(test.data(), test.size()/2);
    ad.update(test.data()+test.size()/2, test.size()-test.size()/2);
    ASSERT_EQ(ad.val(), all_ad);
}
 
TEST(adler32, second_half_update)
{
    Adler32 ad;
    ad.update(test.data()+test.size()/2, test.size()-test.size()/2);
    ASSERT_EQ(ad.val(), last64_ad);
}
 
TEST(adler32, update_and_reset)
{
    Adler32 ad;
    ASSERT_EQ(ad.update(test.data(), test.size()), all_ad);
    ASSERT_EQ(ad.reset(test.data()+test.size()/2, test.size()-test.size()/2), last64_ad);
    ASSERT_EQ(ad.reset(), 1);
}
 
TEST(adler32, combine)
{
    Adler32 first(test.data(), test.size()/2),
            second(test.data()+test.size()/2, test.size()/2);
 
    ASSERT_EQ(first.combine(second), all_ad);
}
 
TEST(adler32, rolling_update)
{
    Adler32 ad;
    size_t sz = test.size();                // 128 bytes
    
    ad.reset(test.data(), sz/2);            // first 64 bytes, sets window size to 64
    ASSERT_EQ(ad.size(), 64);
    
    // rolling 64 byte window, will calculate the checksum at each 64 byte window
    for (size_t i = 0; i < 64; i++)
    {
        ad.rotate(test[i], test[64+i]);     // first byte is 0-63, last is 64-127
    }
    ASSERT_EQ(ad, last64_ad);               // end up with the last 64 bytes checksum
}
 
TEST(adler32, verify_large_blocks)
{
    Adler32 ad;
    Adler32 vad;
 
    int datasz = 1<<14; // 512, block will be up to 5096
    char dat[datasz];
 
    scc::crypto::RandomEngine::rand_bytes(dat, datasz);
 
    for (int blksz = 1; blksz < datasz>>1; blksz <<= 1)
    {
        cout << "testing adler32 rolling checksum for block size: " << blksz << endl;
        
        ad.reset(&dat[0], blksz);       // reset the checksum we will use for rolling
 
        for (int i = 0; i < datasz-blksz; i++)
        {
            vad.reset(&dat[i], blksz);          // calculate the current block directly
            ASSERT_EQ(ad, vad);
            ad.rotate(dat[i], dat[i+blksz]);    // calculate the next window via rolling
        }
    }
}