while (in != null) {
      int result = in.read();
      if (result != -1) {
        return result;
      }
      advance();
    }
    return -1;
  }

  @Override
  public int read(byte[] b, int off, int len) throws IOException {
    checkNotNull(b);
    while (in != null) {
      int result = in.read(b, off, len);
      if (result != -1) {
        return result;
      }
      advance();
    }

    assert n1 <= n2;
    if (IntMath.log2(n2, CEILING) * (n2 - n1) < Long.SIZE - 1) {
      // the result will definitely fit into a long
      long result = 1;
      for (int i = n1 + 1; i <= n2; i++) {
        result *= i;
      }
      return BigInteger.valueOf(result);
    }

    /*
     * We want each multiplication to have both sides with approximately the same number of digits.

	}

	for i, testCase := range testCases {
		result := testCase.tid.String()

		if result != testCase.expectedResult {
			t.Fatalf("test %v: result: expected: %v, got: %v", i+1, testCase.expectedResult, result)
		}
	}
}

func TestTargetDToARN(t *testing.T) {
	tid := TargetID{"1", "webhook"}
	testCases := []struct {

	}

	for i, testCase := range testCases {
		result := testCase.tid.String()

		if result != testCase.expectedResult {
			t.Fatalf("test %v: result: expected: %v, got: %v", i+1, testCase.expectedResult, result)
		}
	}
}

func TestTargetDToARN(t *testing.T) {
	tid := TargetID{"1", "webhook"}
	testCases := []struct {

    BigInteger result;
    do {
      result = randomNonNegativeBigInteger(numBits);
    } while (result.signum() == 0);
    return result;
  }

  /**
   * Generates a number in [0, 2^numBits) with an exponential distribution. The floor of the log2 of
   * the result is chosen uniformly at random in [0, numBits), and then the result is chosen in that

            if (OperatingSystem.current().isWindows) {
                commandLine = listOf("cmd.exe", "/d", "/c") + commandLine
            }
        }
        return execOutput.result.zip(execOutput.standardOutput.asText) { result, outputText ->
            if (result.exitValue == 0) outputText.trim()
            else "<unknown>" // It's a source distribution, we don't know.
        }
    }

    }

    @Override
    protected <RESULT extends AccessToken> RESULT createEntity(Map<String, Object> source, Class<? extends RESULT> entityType) {
        try {
            final RESULT result = entityType.newInstance();
            result.setCreatedBy(DfTypeUtil.toString(source.get("createdBy")));
            result.setCreatedTime(DfTypeUtil.toLong(source.get("createdTime")));

    }

    @Override
    protected <RESULT extends KeyMatch> RESULT createEntity(Map<String, Object> source, Class<? extends RESULT> entityType) {
        try {
            final RESULT result = entityType.newInstance();
            result.setBoost(DfTypeUtil.toFloat(source.get("boost")));
            result.setCreatedBy(DfTypeUtil.toString(source.get("createdBy")));
            result.setCreatedTime(DfTypeUtil.toLong(source.get("createdTime")));

    }

    @Override
    protected <RESULT extends CrawlingInfo> RESULT createEntity(Map<String, Object> source, Class<? extends RESULT> entityType) {
        try {
            final RESULT result = entityType.newInstance();
            result.setCreatedTime(DfTypeUtil.toLong(source.get("createdTime")));
            result.setExpiredTime(DfTypeUtil.toLong(source.get("expiredTime")));
            result.setName(DfTypeUtil.toString(source.get("name")));

                        // explicitly exclude. Set result and stop processing.
                        result = false;
                        break;
                    }
                }
                // check for exact match
                else if (repo.equals(originalId)) {
                    result = true;
                    break;
                }