Method sortDict

Fleece/Core/Encoder.cc:801–839

    }

    void Encoder::sortDict(valueArray &items) {
        auto &keys = items.keys;
        size_t n = keys.size();
        if (n < 2)
            return;

        // Fill in the pointers of any keys that refer to inline strings:
        for (unsigned i = 0; i < n; i++) {
            if (keys[i].buf == nullptr) {
                const Value *item = &items[2*i];
                if (item->tag() == kStringTag) {
                    keys[i].buf = offsetby(item, 1);                    // inline string
                } else {
                    assert(item->tag() == kShortIntTag);
                    keys[i] = {nullptr, (size_t)item->asUnsigned()};    // integer
                }
            }
        }

        // Construct an array that describes the permutation of item indices:
        TempArray(indices, const FLSlice*, n);
        const FLSlice* base = &keys[0];
        for (unsigned i = 0; i < n; i++)
            indices[i] = base + i;
        std::sort(&indices[0], &indices[n], &compareKeysByIndex);
        // indices[i] is now a pointer to the Value that should go at index i

        // Now rewrite items according to the permutation in indices:
        TempArray(oldBuf, char, 2*n * sizeof(Value));
        auto old = (Value*)oldBuf;
        memcpy(old, &items[0], 2*n * sizeof(Value));
        for (size_t i = 0; i < n; i++) {
            auto j = indices[i] - base;
            if ((ssize_t)i != j) {
                items[2*i]   = old[2*j];
                items[2*i+1] = old[2*j+1];
            }
        }
    }

} }