Converts a hexadecimal character to an integer.
@param ch A character to convert to an integer digit @param index The index of the character in the source @return An integer @throws IllegalArgumentException if ch is an illegal hex character
See Implementation
Converts a hexadecimal character to an integer.
@param ch A character to convert to an integer digit @param index The index of the character in the source @return An integer @throws IllegalArgumentException if ch is an illegal hex character