| # buf = n0 + n + 2 * NODE_HEADER_SIZE + nd.alignedsize, buf1 = buf, n + 2 * NODE_HEADER_SIZE + nd.alignedsize ≤ # buf, n + NODE_HEADER_SIZE ≤ # buf ⊦ ∀ buf, err. (err = ESUCCESS ∨ ⌊err⌋ ) ∧ # buf = # buf1 ∧ subarray(buf, 0, n) = subarray(buf1, 0, n) ∧ subarray(buf, n + NODE_HEADER_SIZE, # buf - n + NODE_HEADER_SIZE) = subarray(buf1, n + NODE_HEADER_SIZE, # buf - n + NODE_HEADER_SIZE) ∧ (err = ESUCCESS → is-encoded(nodeheader(node-size-headerless(nd), false), subarray(buf, n, NODE_HEADER_SIZE))) → ⟪m3 := n; if err = ESUCCESS then encode_node_headerless#(nd, m3 + NODE_HEADER_SIZE; buf, m; err); m0 := align↑(node-size-headerless(nd), 2 * NODE_HEADER_SIZE); if err = ESUCCESS then {buf := fill(buf, empty, m3 + NODE_HEADER_SIZE + node-size-headerless(nd), m0 - node-size-headerless(nd)); buf := copy(validtrailer, 0, buf, m3 + NODE_HEADER_SIZE + m0, NODE_HEADER_SIZE)}; m2 := 2 * NODE_HEADER_SIZE + m0⟫ ( (err = ESUCCESS ∨ ⌊err⌋ ) ∧ # buf = # buf1 ∧ subarray(buf, 0, n) = subarray(buf1, 0, n) ∧ subarray(buf, n + 2 * NODE_HEADER_SIZE + nd.alignedsize, n0) = subarray(buf1, n + 2 * NODE_HEADER_SIZE + nd.alignedsize, n0) ∧ ( err = ESUCCESS → (∃ buf0, buf1. subarray(buf, n, 2 * NODE_HEADER_SIZE + nd.alignedsize) = buf0 + buf1 + validtrailer ∧ is-encoded(nodeheader(node-size-headerless(nd), false), buf0) ∧ is-encoded(nd, subarray(buf1, 0, node-size-headerless(nd))) ∧ # buf1 = nd.alignedsize) ∧ m2 = 2 * NODE_HEADER_SIZE + nd.alignedsize)) |
# buf0 = # buf, # buf = n0 + n + 2 * NODE_HEADER_SIZE + nd.alignedsize, subarray(buf0, 0, n) = subarray(buf, 0, n), subarray(buf0, n + NODE_HEADER_SIZE, # buf - n + NODE_HEADER_SIZE) = subarray(buf, n + NODE_HEADER_SIZE, # buf - n + NODE_HEADER_SIZE), n + NODE_HEADER_SIZE ≤ # buf, n + 2 * NODE_HEADER_SIZE + nd.alignedsize ≤ # buf, err = ESUCCESS → is-encoded(nodeheader(node-size-headerless(nd), false), subarray(buf0, n, NODE_HEADER_SIZE)), err = ESUCCESS ∨ ⌊err⌋ ⊦ ⟪m3 := n; if err = ESUCCESS then encode_node_headerless#(nd, m3 + NODE_HEADER_SIZE; buf0, m; err); m0 := align↑(node-size-headerless(nd), 2 * NODE_HEADER_SIZE); if err = ESUCCESS then {buf0 := fill(buf0, empty, m3 + NODE_HEADER_SIZE + node-size-headerless(nd), m0 - node-size-headerless(nd)); buf0 := copy(validtrailer, 0, buf0, m3 + NODE_HEADER_SIZE + m0, NODE_HEADER_SIZE)}; m2 := 2 * NODE_HEADER_SIZE + m0⟫ ( (err = ESUCCESS ∨ ⌊err⌋ ) ∧ # buf0 = # buf ∧ subarray(buf0, 0, n) = subarray(buf, 0, n) ∧ subarray(buf0, n + 2 * NODE_HEADER_SIZE + nd.alignedsize, n0) = subarray(buf, n + 2 * NODE_HEADER_SIZE + nd.alignedsize, n0) ∧ ( err = ESUCCESS → (∃ buf2, buf1. subarray(buf0, n, 2 * NODE_HEADER_SIZE + nd.alignedsize) = buf2 + buf1 + validtrailer ∧ is-encoded(nodeheader(node-size-headerless(nd), false), buf2) ∧ is-encoded(nd, subarray(buf1, 0, node-size-headerless(nd))) ∧ # buf1 = nd.alignedsize) ∧ m2 = 2 * NODE_HEADER_SIZE + nd.alignedsize))