Function computeBytecodePattern

packages/utils/src/fingerprint.ts:15–21

(bytecode: Uint8Array)

// consecutive push instructions is replaced by a single push of the run length.
// See: https://gitlab.com/0353F40E/smart-contract-fingerprinting/
export function computeBytecodePattern(bytecode: Uint8Array): Uint8Array {
  const opcodes = decodeAuthenticationInstructions(bytecode).map((instruction) => instruction.opcode);
  const chunks = groupByPushRun(opcodes).map((run) => (
    isPushOpcode(run[0]) ? encodePushCount(run.length) : Uint8Array.from(run)
  ));
  return flattenBinArray(chunks);
}

// Split opcodes into consecutive runs that are either all pushes or all non-pushes.
function groupByPushRun(opcodes: Op[]): Op[][] {