Package org.apache.lucene.util

Class UnicodeUtil

  • public final class UnicodeUtil
extends Object
    Class to encode java's UTF16 char[] into UTF8 byte[] without always allocating a new byte[] as String.getBytes("UTF-8") does.

    • Field Detail

      • BIG_TERM

        public static final BytesRef BIG_TERM
        A binary term consisting of a number of 0xff bytes, likely to be bigger than other terms (e.g. collation keys) one would normally encounter, and definitely bigger than any UTF-8 terms.

        WARNING: This is not a valid UTF8 Term

    • Method Detail

      • UTF16toUTF8WithHash

        public static int UTF16toUTF8WithHash​(char[] source,
                                      int offset,
                                      int length,
                                      BytesRef result)
        Encode characters from a char[] source, starting at offset for length chars. Returns a hash of the resulting bytes. After encoding, result.offset will always be 0.

      • UTF16toUTF8

        public static void UTF16toUTF8​(char[] source,
                               int offset,
                               int length,
                               BytesRef result)
        Encode characters from a char[] source, starting at offset for length chars. After encoding, result.offset will always be 0.

      • UTF16toUTF8

        public static void UTF16toUTF8​(CharSequence s,
                               int offset,
                               int length,
                               BytesRef result)
        Encode characters from this String, starting at offset for length characters. After encoding, result.offset will always be 0.

      • validUTF16String

        public static boolean validUTF16String​(CharSequence s)

      • validUTF16String

        public static boolean validUTF16String​(char[] s,
                                       int size)

      • codePointCount

        public static int codePointCount​(BytesRef utf8)
        Returns the number of code points in this UTF8 sequence.

        This method assumes valid UTF8 input. This method does not perform full UTF8 validation, it will check only the first byte of each codepoint (for multi-byte sequences any bytes after the head are skipped).

        Throws:
        IllegalArgumentException - If invalid codepoint header byte occurs or the content is prematurely truncated.

      • UTF8toUTF32

        public static void UTF8toUTF32​(BytesRef utf8,
                               IntsRef utf32)

        This method assumes valid UTF8 input. This method does not perform full UTF8 validation, it will check only the first byte of each codepoint (for multi-byte sequences any bytes after the head are skipped).

        Throws:
        IllegalArgumentException - If invalid codepoint header byte occurs or the content is prematurely truncated.

      • newString

        public static String newString​(int[] codePoints,
                               int offset,
                               int count)
        Cover JDK 1.5 API. Create a String from an array of codePoints.
        Parameters:
        codePoints - The code array
        offset - The start of the text in the code point array
        count - The number of code points
        Returns:
        a String representing the code points between offset and count
        Throws:
        IllegalArgumentException - If an invalid code point is encountered
        IndexOutOfBoundsException - If the offset or count are out of bounds.

      • toHexString

        public static String toHexString​(String s)

      • UTF8toUTF16

        public static void UTF8toUTF16​(byte[] utf8,
                               int offset,
                               int length,
                               CharsRef chars)
        Interprets the given byte array as UTF-8 and converts to UTF-16. The CharsRef will be extended if it doesn't provide enough space to hold the worst case of each byte becoming a UTF-16 codepoint.

        NOTE: Full characters are read, even if this reads past the length passed (and can result in an ArrayOutOfBoundsException if invalid UTF-8 is passed). Explicit checks for valid UTF-8 are not performed.