Common (All Contexts)

These wrappers are available in all invocation contexts (refine, accumulate, authorize).

Gas

All context classes expose remainingGas() which returns the gas remaining after the call (ecalli 0):

const gasLeft = ctx.remainingGas();  // i64

Service Data

High-level wrappers for service storage (read/write) and account info (info).

// Read/write access to the current service (preferred)
const storage = ctx.serviceData();
const info = storage.info();                  // Optional<AccountInfo>
const val = storage.read(key);               // key: BytesBlob → Optional<BytesBlob>
const result = storage.write(key, value);    // key/value: BytesBlob → Result<OptionalN<u64>, WriteError>

// Read-only access to another service by ID
const other = ServiceData.create(42);
const otherInfo = other.info();

Preimages

Wraps the lookup ecalli with buffer management and auto-expansion. Each context provides the appropriate preimage helper via ctx.preimages().

const preimages = ctx.preimages();  // Preimages, RefinePreimages, or AccumulatePreimages
const hash = Bytes32.zero();  // or a real hash
const result = preimages.lookup(hash);  // Optional<BytesBlob>
if (result.isSome) {
  const data = result.val!;
  // use data...
}

// Look up a preimage for a different service:
const other = preimages.lookup(hash, 42);

Context-specific extensions (RefinePreimages, AccumulatePreimages) are documented under their respective context pages.

Cryptography

Pure-AssemblyScript crypto primitives. These compile to the PVM target with no host-call dependencies.

Blake2b-256

RFC 7693 Blake2b, unkeyed, 32-byte output — the JAM preimage hash.

import { blake2b256 } from "@fluffylabs/as-lan";

const digest = blake2b256(payload);  // Uint8Array(32)

The implementation supports a single input up to 2⁶⁴ − 1 bytes (the high 64 bits of the RFC 7693 counter are hardcoded to zero). Chained hashing of arbitrarily long streams is out of scope.