"""
HexDump program in Cobra.
by Johannes Krampf, Mike Hopkirk, Charles Esterbrook

Produces output like hexdump -C  
"""


class HexDump

    def main
        args = CobraCore.commandLineArgs
        if args.count <> 2
            binaryName = Path.getFileName(args[0])
            print 'Usage: [binaryName] \[filename\]'
            CobraCore.exit(1)
        for i in 1 : args.count
            .dumpFileNamed(args[i], 16)

    def dumpFileNamed(filename as String, width as int)
        require width % 2 == 0
        .dumpBytes(FileByteStream(filename).read, width)

    def dumpBytes(bytes as int*, width as int)
        require
            width % 2 == 0  # width must be even
        test
            cases = [
                ['aoeu', '00000000  61 6f  65 75  |aoeu|\n00000004\n'],
                ['aoe\nasdf', '00000000  61 6f  65 0a  |aoe.|\n00000004  61 73  64 66  |asdf|\n00000008\n'],
            ]
            for input, expected in cases
                sw = StringWriter()
                print to sw
                    bytes = for b in Encoding.ascii.getBytes(input) get b to int
                    HexDump().dumpBytes(bytes, 4)
                actual = sw.toString.replace('\r', '')
                assert actual == expected, input
        body
            halfWidth = width // 2
            hexPart = asciiPart = ''    
            for n, byte in bytes.toList.numbered
                if (n % width) == 0  # file offset in hex
                    line = '[n:x8]'
                    hexPart += '[line]  '
                hex = '[byte:x2]'
                hexPart += '[hex] '  #  accumulate hex chars space separated
                asciiPart += if(0x1f < byte < 0x80, Convert.toChar(byte).toString, '.')
                if (n+1) % width == 0  # display a full line
                    print '[hexPart] |[asciiPart]|'
                    hexPart = asciiPart = ''
                else if (n+1) % halfWidth == 0  # extra space in middle of hex
                    hexPart += ' '

            n += 1
            if n % width
                # space pad both parts of partially filled last line 
                hpad = 3*(width - (n % width)) + if(0 < (n % width) <= halfWidth, 1, 0)
                hexPart += ' '.padLeft(hpad)
                apad = width - (n % width)
                asciiPart += ' '.padLeft(apad)
                print '[hexPart] |[asciiPart]|'

            print '[n:x8]'  # file byte count


class FileByteStream

    var _input as FileStream

    cue init(filename as String)
        base.init
        try
            _input = File.openRead(filename)
        catch ioe as IOException
            print 'I/O Error: [ioe.message]'

    def read as int*
        while true
            current = _input.readByte
            if current == -1, break
            yield current
        yield break