public static Map deserialize()

in src/main/java/com/amazonaws/encryptionsdk/internal/EncryptionContextSerializer.java [136:202]
50 lines of code
10 McCabe index (conditional complexity)

  public static Map<String, String> deserialize(final byte[] b) {
    try {
      if (b == null) {
        return null;
      }

      if (b.length == 0) {
        return (Collections.<String, String>emptyMap());
      }

      final ByteBuffer encryptionContextBytes = ByteBuffer.wrap(b);

      // retrieve the number of entries first
      final int entryCount = encryptionContextBytes.getShort();
      if (entryCount <= 0 || entryCount > Short.MAX_VALUE) {
        throw new AwsCryptoException(
            "The number of entries in encryption context must be greater than 0 and smaller than "
                + Short.MAX_VALUE);
      }

      final CharsetDecoder decoder = StandardCharsets.UTF_8.newDecoder();

      // ensure all failures in decoder are reported.
      decoder.onMalformedInput(CodingErrorAction.REPORT);
      decoder.onUnmappableCharacter(CodingErrorAction.REPORT);

      final Map<String, String> result = new HashMap<>(entryCount);
      for (int i = 0; i < entryCount; i++) {
        // retrieve key
        final int keyLen = encryptionContextBytes.getShort();
        if (keyLen <= 0 || keyLen > Short.MAX_VALUE) {
          throw new AwsCryptoException(
              "Key length must be greater than 0 and smaller than " + Short.MAX_VALUE);
        }

        final ByteBuffer keyBytes = encryptionContextBytes.slice();
        Utils.limit(keyBytes, keyLen);
        Utils.position(encryptionContextBytes, encryptionContextBytes.position() + keyLen);

        final int valueLen = encryptionContextBytes.getShort();
        if (valueLen <= 0 || valueLen > Short.MAX_VALUE) {
          throw new AwsCryptoException(
              "Value length must be greater than 0 and smaller than " + Short.MAX_VALUE);
        }

        // retrieve value
        final ByteBuffer valueBytes = encryptionContextBytes.slice();
        Utils.limit(valueBytes, valueLen);
        Utils.position(encryptionContextBytes, encryptionContextBytes.position() + valueLen);

        final CharBuffer keyChars = decoder.decode(keyBytes);
        final CharBuffer valueChars = decoder.decode(valueBytes);

        // check for duplicate entries.
        if (result.put(keyChars.toString(), valueChars.toString()) != null) {
          throw new AwsCryptoException("Encryption context contains duplicate entries.");
        }
      }

      return result;
    } catch (CharacterCodingException e) {
      throw new IllegalArgumentException(
          "Encryption context contains an invalid unicode character");
    } catch (BufferUnderflowException e) {
      throw new AwsCryptoException("Invalid encryption context. Expected more bytes.", e);
    }
  }