Class Utf8.Processor

java.lang.Object
com.google.protobuf.Utf8.Processor
Direct Known Subclasses:
Utf8.SafeProcessor, Utf8.UnsafeProcessor
Enclosing class:
Utf8

abstract static class Utf8.Processor extends Object
A processor of UTF-8 strings, providing methods for checking validity and encoding.
  • Constructor Details

    • Processor

      Processor()
  • Method Details

    • isValidUtf8

      final boolean isValidUtf8(byte[] bytes, int index, int limit)
      Returns true if the given byte array slice is a well-formed UTF-8 byte sequence. The range of bytes to be checked extends from index index, inclusive, to limit, exclusive.

      This is a convenience method, equivalent to partialIsValidUtf8(bytes, index, limit) == Utf8.COMPLETE.

    • partialIsValidUtf8

      abstract int partialIsValidUtf8(int state, byte[] bytes, int index, int limit)
      Tells whether the given byte array slice is a well-formed, malformed, or incomplete UTF-8 byte sequence. The range of bytes to be checked extends from index index, inclusive, to limit, exclusive.
      Parameters:
      state - either Utf8.COMPLETE (if this is the initial decoding operation) or the value returned from a call to a partial decoding method for the previous bytes
      Returns:
      Utf8.MALFORMED if the partial byte sequence is definitely not well-formed, Utf8.COMPLETE if it is well-formed (no additional input needed), or if the byte sequence is "incomplete", i.e. apparently terminated in the middle of a character, an opaque integer "state" value containing enough information to decode the character when passed to a subsequent invocation of a partial decoding method.
    • isValidUtf8

      final boolean isValidUtf8(ByteBuffer buffer, int index, int limit)
      Returns true if the given portion of the ByteBuffer is a well-formed UTF-8 byte sequence. The range of bytes to be checked extends from index index, inclusive, to limit, exclusive.

      This is a convenience method, equivalent to partialIsValidUtf8(bytes, index, limit) == Utf8.COMPLETE.

    • partialIsValidUtf8

      final int partialIsValidUtf8(int state, ByteBuffer buffer, int index, int limit)
      Indicates whether or not the given buffer contains a valid UTF-8 string.
      Parameters:
      buffer - the buffer to check.
      Returns:
      true if the given buffer contains a valid UTF-8 string.
    • partialIsValidUtf8Direct

      abstract int partialIsValidUtf8Direct(int state, ByteBuffer buffer, int index, int limit)
      Performs validation for direct ByteBuffer instances.
    • partialIsValidUtf8Default

      final int partialIsValidUtf8Default(int state, ByteBuffer buffer, int index, int limit)
      Performs validation for ByteBuffer instances using the ByteBuffer API rather than potentially faster approaches. This first completes validation for the current character (provided by state) and then finishes validation for the sequence.
    • partialIsValidUtf8

      private static int partialIsValidUtf8(ByteBuffer buffer, int index, int limit)
      Performs validation for ByteBuffer instances using the ByteBuffer API rather than potentially faster approaches.
    • decodeUtf8

      abstract String decodeUtf8(byte[] bytes, int index, int size) throws InvalidProtocolBufferException
      Decodes the given byte array slice into a String.
      Throws:
      InvalidProtocolBufferException - if the byte array slice is not valid UTF-8
    • decodeUtf8

      final String decodeUtf8(ByteBuffer buffer, int index, int size) throws InvalidProtocolBufferException
      Decodes the given portion of the ByteBuffer into a String.
      Throws:
      InvalidProtocolBufferException - if the portion of the buffer is not valid UTF-8
    • decodeUtf8Direct

      abstract String decodeUtf8Direct(ByteBuffer buffer, int index, int size) throws InvalidProtocolBufferException
      Decodes direct ByteBuffer instances into String.
      Throws:
      InvalidProtocolBufferException
    • decodeUtf8Default

      final String decodeUtf8Default(ByteBuffer buffer, int index, int size) throws InvalidProtocolBufferException
      Decodes ByteBuffer instances using the ByteBuffer API rather than potentially faster approaches.
      Throws:
      InvalidProtocolBufferException
    • encodeUtf8

      abstract int encodeUtf8(String in, byte[] out, int offset, int length)
      Encodes an input character sequence (in) to UTF-8 in the target array (out). For a string, this method is similar to
      
       byte[] a = string.getBytes(UTF_8);
       System.arraycopy(a, 0, bytes, offset, a.length);
       return offset + a.length;
       
      but is more efficient in both time and space. One key difference is that this method requires paired surrogates, and therefore does not support chunking. While String.getBytes(UTF_8) replaces unpaired surrogates with the default replacement character, this method throws Utf8.UnpairedSurrogateException.

      To ensure sufficient space in the output buffer, either call Utf8.encodedLength(java.lang.String) to compute the exact amount needed, or leave room for Utf8.MAX_BYTES_PER_CHAR * sequence.length(), which is the largest possible number of bytes that any input can be encoded to.

      Parameters:
      in - the input character sequence to be encoded
      out - the target array
      offset - the starting offset in bytes to start writing at
      length - the length of the bytes, starting from offset
      Returns:
      the new offset, equivalent to offset + Utf8.encodedLength(sequence)
      Throws:
      Utf8.UnpairedSurrogateException - if sequence contains ill-formed UTF-16 (unpaired surrogates)
      ArrayIndexOutOfBoundsException - if sequence encoded in UTF-8 is longer than bytes.length - offset
    • encodeUtf8

      final void encodeUtf8(String in, ByteBuffer out)
      Encodes an input character sequence (in) to UTF-8 in the target buffer (out). Upon returning from this method, the out position will point to the position after the last encoded byte. This method requires paired surrogates, and therefore does not support chunking.

      To ensure sufficient space in the output buffer, either call Utf8.encodedLength(java.lang.String) to compute the exact amount needed, or leave room for Utf8.MAX_BYTES_PER_CHAR * in.length(), which is the largest possible number of bytes that any input can be encoded to.

      Parameters:
      in - the source character sequence to be encoded
      out - the target buffer
      Throws:
      Utf8.UnpairedSurrogateException - if in contains ill-formed UTF-16 (unpaired surrogates)
      ArrayIndexOutOfBoundsException - if in encoded in UTF-8 is longer than out.remaining()
    • encodeUtf8Direct

      abstract void encodeUtf8Direct(String in, ByteBuffer out)
      Encodes the input character sequence to a direct ByteBuffer instance.
    • encodeUtf8Default

      final void encodeUtf8Default(String in, ByteBuffer out)
      Encodes the input character sequence to a ByteBuffer instance using the ByteBuffer API, rather than potentially faster approaches.