Function dictMerge

src/dict.cpp:197–332

}

int dictMerge(dict *dst, dict *src)
{
#define MERGE_BLOCK_SIZE 4
    dictEntry *rgdeT[MERGE_BLOCK_SIZE];

    assert(dst != src);
    if (dictSize(src) == 0)
        return DICT_OK;
    
    if (dictSize(dst) == 0)
    {
        dict::swap(*dst, *src);
        std::swap(dst->pauserehash, src->pauserehash);
        return DICT_OK;
    }

    size_t expectedSize = dictSize(src) + dictSize(dst);
    if (dictSize(src) > dictSize(dst) && src->asyncdata == nullptr && dst->asyncdata == nullptr)
    {
        dict::swap(*dst, *src);
        std::swap(dst->pauserehash, src->pauserehash);
    }

    if (!dictIsRehashing(dst) && !dictIsRehashing(src))
    {
        if (dst->ht[0].size >= src->ht[0].size)
        {
            dst->ht[1] = dst->ht[0];
            dst->ht[0] = src->ht[0];
        }
        else
        {
            dst->ht[1] = src->ht[0];
        }
        _dictReset(&src->ht[0]);
        dst->rehashidx = 0;
        assert(dictIsRehashing(dst));
        assert((dictSize(src)+dictSize(dst)) == expectedSize);
        return DICT_OK;
    }

    if (!dictIsRehashing(src) && dictSize(src) > 0 &&
        (src->ht[0].size == dst->ht[0].size || src->ht[0].size == dst->ht[1].size))
    {
        auto &htDst = (src->ht[0].size == dst->ht[0].size) ? dst->ht[0] : dst->ht[1];

        assert(src->ht[0].size == htDst.size);
        for (size_t ide = 0; ide < src->ht[0].size; ide += MERGE_BLOCK_SIZE)
        {
            if (src->ht[0].used == 0)
                break;

            for (int dde = 0; dde < MERGE_BLOCK_SIZE; ++dde) {
                rgdeT[dde] = src->ht[0].table[ide + dde];
                src->ht[0].table[ide + dde] = nullptr;
            }

            for (;;) {