1. A method comprising: defining a 256-bit bitmap, each bit of the bitmap representing an eight-bit character occurrable within a character string and having a value indicating whether the character is a target character, the character string having a plurality of eight-bit characters at a corresponding plurality of positions; determining a first position within the character string at which one of the target characters occurs using the 256-bit bitmap and a processor permutation instruction; and, outputting the first position within the character string at which one of the target characters occurs, as has been determined.