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Proof step 20 from proof encode-contract (previous step)

# buf1 = # buf, subarray(buf1, 0, n) = subarray(buf, 0, n), subarray(buf1, n + ENCODED_ELEM_SIZE, # buf - n + ENCODED_ELEM_SIZE) = subarray(buf, n + ENCODED_ELEM_SIZE, # buf - n + ENCODED_ELEM_SIZE), n + ENCODED_ELEM_SIZE ≤ # buf, err = ESUCCESS → is-encoded(a, subarray(buf1, n, ENCODED_ELEM_SIZE)) ∧ m = ENCODED_ELEM_SIZE, err = ESUCCESS ∨ ⌊err⌋ ⊦ err = ESUCCESS ∧ isempty(buf1, n, m), (err = ESUCCESS ∨ ⌊err⌋ ) ∧ (err = ESUCCESS → is-encoded-nonempty(a, subarray(buf1, n, ENCODED_ELEM_SIZE)))

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Proof step 21:
⊦ is-encoded-nonempty(a, buf) ↔ is-encoded(a, buf) ∧ ¬ isempty(buf)
Proof step 22:
# buf1 = # buf, subarray(buf1, n, ENCODED_ELEM_SIZE) = mkempbuf(ENCODED_ELEM_SIZE), subarray(buf1, 0, n) = subarray(buf, 0, n), subarray(buf1, n + ENCODED_ELEM_SIZE, # buf - n + ENCODED_ELEM_SIZE) = subarray(buf, n + ENCODED_ELEM_SIZE, # buf - n + ENCODED_ELEM_SIZE), is-encoded(a, subarray(buf1, n, ENCODED_ELEM_SIZE)), n + ENCODED_ELEM_SIZE ≤ # buf ⊦ isempty(buf1, n, ENCODED_ELEM_SIZE)

Rule argument

Additional information

Used simplifier rules: is-encoded-nonempty: ⊦ is-encoded-nonempty(a, buf) ↔ is-encoded(a, buf) ∧ ¬ isempty(buf);%is-encoded-size: ⊦ is-encoded(a, buf) → # buf = ENCODED_ELEM_SIZE; (forward) from specification encoding-fixed-size% ⊦ # subarray(buf, m, n) = n; (s)% ⊦ isempty(buf) ↔ buf = mkempbuf(# buf); (s)