Function processSyncInput

lib/internal/streams/iter/transform.js:557–615

(input, flushFlag)

      let pendingBytes = 0;

      function processSyncInput(input, flushFlag) {
        let inOff = 0;
        let availIn = TypedArrayPrototypeGetByteLength(input);
        let availOutBefore = chunkSize - outOffset;

        handle.writeSync(flushFlag,
                         input, inOff, availIn,
                         outBuf, outOffset, availOutBefore);
        if (error) throw error;

        while (true) {
          const availOut = writeState[0];
          const availInAfter = writeState[1];
          const have = availOutBefore - availOut;
          const bufferExhausted = availOut === 0 ||
                                  outOffset + have >= chunkSize;

          if (have > 0) {
            if (bufferExhausted && outOffset === 0) {
              // Entire buffer filled - yield directly, no copy.
              ArrayPrototypePush(pending, outBuf);
            } else if (bufferExhausted) {
              // Tail filled, buffer being replaced - subarray is safe.
              ArrayPrototypePush(pending,
                                 outBuf.subarray(outOffset, outOffset + have));
            } else {
              // Partial fill, buffer reused - must copy.
              ArrayPrototypePush(pending,
                                 TypedArrayPrototypeSlice(outBuf,
                                                          outOffset,
                                                          outOffset + have));
            }
            pendingBytes += have;
            outOffset += have;
          }

          if (bufferExhausted) {
            outBuf = Buffer.allocUnsafe(chunkSize);
            outOffset = 0;
          }

          if (availOut === 0) {
            // Engine has more output - loop.
            const consumed = availIn - availInAfter;
            inOff += consumed;
            availIn = availInAfter;
            availOutBefore = chunkSize - outOffset;

            handle.writeSync(flushFlag,
                             input, inOff, availIn,
                             outBuf, outOffset, availOutBefore);
            if (error) throw error;
            continue;
          }

          // All input consumed.
          break;
        }