Package org.apache.pdfbox.util

Class Hex

  • public final class Hex
extends java.lang.Object
    Utility functions for hex encoding.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private static byte[] HEX_BYTES
      for hex conversion.
      private static char[] HEX_CHARS  
      private static org.apache.commons.logging.Log LOG  

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      private Hex()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static byte[] decodeBase64​(java.lang.String base64Value)
      Decode a base64 String.
      static byte[] decodeHex​(java.lang.String s)
      Decodes a hex String into a byte array.
      static byte[] getBytes​(byte b)
      Returns the bytes corresponding to the ASCII hex encoding of the given byte.
      static byte[] getBytes​(byte[] bytes)
      Returns the bytes corresponding to the ASCII hex encoding of the given bytes.
      static char[] getChars​(short num)
      Returns the characters corresponding to the ASCII hex encoding of the given short.
      static char[] getCharsUTF16BE​(java.lang.String text)
      Takes the characters in the given string, convert it to bytes in UTF16-BE format and build a char array that corresponds to the ASCII hex encoding of the resulting bytes.
      static int getHexValue​(char c)
      Converts a given character to its corresponding hexadecimal value.
      private static int getHighNibble​(byte b)
      Get the high nibble of the given byte.
      private static int getLowNibble​(byte b)
      Get the low nibble of the given byte.
      static java.lang.String getString​(byte b)
      Returns a hex string of the given byte.
      static java.lang.String getString​(byte[] bytes)
      Returns a hex string of the given byte array.
      static void writeHexByte​(byte b, java.io.OutputStream output)
      Writes the given byte as hex value to the given output stream.
      static void writeHexBytes​(byte[] bytes, java.io.OutputStream output)
      Writes the given byte array as hex value to the given output stream.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • LOG

        private static final org.apache.commons.logging.Log LOG

      • HEX_BYTES

        private static final byte[] HEX_BYTES
        for hex conversion. https://stackoverflow.com/questions/2817752/java-code-to-convert-byte-to-hexadecimal

      • HEX_CHARS

        private static final char[] HEX_CHARS

    • Constructor Detail

      • Hex

        private Hex()

    • Method Detail

      • getString

        public static java.lang.String getString​(byte b)
        Returns a hex string of the given byte.
        Parameters:
        b - the byte to be converted
        Returns:
        the hex string representing the given byte

      • getString

        public static java.lang.String getString​(byte[] bytes)
        Returns a hex string of the given byte array.
        Parameters:
        bytes - the bytes to be converted
        Returns:
        the hex string representing the given bytes

      • getBytes

        public static byte[] getBytes​(byte b)
        Returns the bytes corresponding to the ASCII hex encoding of the given byte.
        Parameters:
        b - the byte to be converted
        Returns:
        the ASCII hex encoding of the given byte

      • getBytes

        public static byte[] getBytes​(byte[] bytes)
        Returns the bytes corresponding to the ASCII hex encoding of the given bytes.
        Parameters:
        bytes - the bytey to be converted
        Returns:
        the ASCII hex encoding of the given bytes

      • getChars

        public static char[] getChars​(short num)
        Returns the characters corresponding to the ASCII hex encoding of the given short.
        Parameters:
        num - the short value to be converted
        Returns:
        the ASCII hex encoding of the given short value

      • getCharsUTF16BE

        public static char[] getCharsUTF16BE​(java.lang.String text)
        Takes the characters in the given string, convert it to bytes in UTF16-BE format and build a char array that corresponds to the ASCII hex encoding of the resulting bytes. Example: 
           getCharsUTF16BE("ab") == new char[]{'0','0','6','1','0','0','6','2'}
        Parameters:
        text - The string to convert
        Returns:
        The string converted to hex

      • writeHexByte

        public static void writeHexByte​(byte b,
                                java.io.OutputStream output)
                         throws java.io.IOException
        Writes the given byte as hex value to the given output stream.
        Parameters:
        b - the byte to be written
        output - the output stream to be written to
        Throws:
        java.io.IOException - exception if anything went wrong

      • writeHexBytes

        public static void writeHexBytes​(byte[] bytes,
                                 java.io.OutputStream output)
                          throws java.io.IOException
        Writes the given byte array as hex value to the given output stream.
        Parameters:
        bytes - the byte array to be written
        output - the output stream to be written to
        Throws:
        java.io.IOException - exception if anything went wrong

      • getHighNibble

        private static int getHighNibble​(byte b)
        Get the high nibble of the given byte.
        Parameters:
        b - the given byte
        Returns:
        the high nibble

      • getLowNibble

        private static int getLowNibble​(byte b)
        Get the low nibble of the given byte.
        Parameters:
        b - the given byte
        Returns:
        the low nibble

      • decodeBase64

        public static byte[] decodeBase64​(java.lang.String base64Value)
        Decode a base64 String.
        Parameters:
        base64Value - a base64 encoded String.
        Returns:
        the decoded String as a byte array.
        Throws:
        java.lang.IllegalArgumentException - if this isn't a base64 encoded string.

      • decodeHex

        public static byte[] decodeHex​(java.lang.String s)
        Decodes a hex String into a byte array.
        Parameters:
        s - A String with ASCII hex.
        Returns:
        decoded byte array.

      • getHexValue

        public static int getHexValue​(char c)
        Converts a given character to its corresponding hexadecimal value. Valid characters are '0'-'9', 'A'-'F', or 'a'-'f'. Returns -256 for invalid characters.

        The value of -256 is chosen so that to hex digits can be combined before checking for an invalid hex string

        Parameters:
        c - the character to be converted to a hexadecimal value
        Returns:
        the hexadecimal value of the character, or -256 if the character is invalid