Application to convert Binary to Decimal

Hello, I need an application that will convert binary number written to the text file to the decimal number written to the text file. Binary is stored in the file in the format of string, so each byte = 1 bit of number. Example of input text file content: 1000010001 Output should be text file with: 529 Requirements: - fast conversion algorithm, should be able to handle HUGE binaries, up to 100M of bits; - use any environment/language; - application to be compartible with Windows OS (unless there is obvious reason this should be done at Linux to match other requirements); - input file size up to 250Mb; - conversion time aproximation; - 2 modes: commandline with params and window or just command line (params = filenames) is ok; Thanks, Nick