| ⊦ m ≤ # buf0 + # buf1 ∧ (m ≥ # buf0 → datasize(buf1, m - # buf0) = 0) → datasize(buf0 + buf1, m) = datasize(buf0, min(m, # buf0)) |
m ≤ # buf0 + # buf1, m ≥ # buf0 → datasize(buf1, m - # buf0) = 0 ⊦ datasize(buf0 + buf1, m) = datasize(buf0, min(m, # buf0))