int outPos = 0, previous = 0;
for (int inPos = 0; inPos < n; inPos++) {
    int delta = uncompressed[inPos] - previous;
    while (delta >= 128) {
        compressed[outPos++] = (delta & 127) | 128;
        delta = delta >> 7;
    }
    compressed[outPos++] = delta;
}