z->avail_in = 0;
z->next_out = df;
z->avail_out = dfallocated;
while ((ret = deflate (z, Z_FINISH)) == Z_OK && (cnt++ <= 100)) {
while ((ret = deflate (z, Z_FINISH)) == Z_OK) {
gvwrite_no_z(job, df, (size_t)(z->next_out - df));