Function CalcChecksum

library/cpp/netliba/v6/block_chain.cpp:7–25

namespace NNetliba {
    ui32 CalcChecksum(const void* p, int size) {
        //return 0;
        //return CalcCrc32(p, size);
        i64 sum = 0;
        const unsigned char *pp = (const unsigned char*)p, *pend = pp + size;
        for (const unsigned char* pend4 = pend - 3; pp < pend4; pp += 4)
            sum += *(const ui32*)pp;

        ui32 left = 0, pos = 0;
        for (; pp < pend; ++pp) {
            pos += ((ui32)*pp) << left;
            left += 8;
        }

        sum += pos;
        sum = (sum & 0xffffffff) + (sum >> 32);
        sum += sum >> 32;
        return (ui32)~sum;
    }

    ui32 CalcChecksum(const TBlockChain& chain) {
        TIncrementalChecksumCalcer ics;