ffb

#!/usr/bin/env python3
import sys, getopt
class State:
    def __init__(self, cmd, bar, jmp):
        self.cmd=cmd
        self.bar=bar
        self.jmp=jmp
#close everything up
def close(code=2):
    global p
    global IMET
    global OMET
    global out
    global inFile
    try:
        p.close()
    except NameError:
        pass
    try:
        out.close()
    except NameError:
        pass
    try:
        inFile.close()
    except NameError:
        pass
    sys.exit(code)
#show help
def showHelp():
    print("""Usage: """+sys.argv[0]+""" [OPTION]... [FILE]
Runs a .ffb file
--inputfile=file      specifies a file to get input from, rather than from a user
--outputfile=file     specifies a file to output to, rather than from the console
-h, --help          shows this help page
""")
#run a command
def runCmd(cmd):
    global tape
    global ip
    global IMET
    global OMET
    global inBuffer
    global inFile
    global out
    if cmd=="LFT":
        ip+=1
        if ip==len(tape):
            tape+=[0]
    elif cmd=="RGT":
        if ip==0:
            tape=[0]+tape
        else:
            ip-=1
    elif cmd=="INC":
        tape[ip]+=1
        if tape[ip]>255:
            tape[ip]=0
        if tape[ip]<0:
            tape[ip]=255
    elif cmd=="DEC":
        tape[ip]-=1
        if tape[ip]>255:
            tape[ip]=0
        if tape[ip]<0:
            tape[ip]=255
    elif cmd=="INP":
        while True:
            if len(inBuffer)>0:
                try:
                    tape[ip]=ord(inBuffer[0])
                except TypeError:
                    tape[ip]=inBuffer[0]
                inBuffer=inBuffer[1:]
                return
            #we need to refill the buffer
            if IMET=="USER":
                inBuffer=input()
                if len(inBuffer)==0:
                    #no input
                    inBuffer=[-1]
            else:
                inBuffer=inFile.read(1)
                if len(inBuffer)==0:
                    #no input
                    inBuffer=[-1]
    elif cmd=="OUT":
        if OMET=="USER":
            print(chr(max(tape[ip],0)),end="")
        else:
            out.write(bytes([max(tape[ip],0)]))
    elif cmd=="HLT":
        close(0)
#IO methods
IMET="USER"
OMET="USER"
#where we save input that is waiting to be used
inBuffer=""
#get arguments
args=sys.argv[1:]
try:
    opts,args=getopt.getopt(args,"h",["help","inputfile=","outputfile="])
except getopt.GetoptError:
    showHelp()
    close(2)
#read options
for opt, arg in opts:
    if opt in ('-h','--help'):
        showHelp()
        close(0)
    elif opt=="--inputfile":
        IMET="FILE"
        try:
            inFile=open(arg,'rb')
            inBuffer=inFile.read()
        except IOError:
            print("ERROR: Could not open input file.")
            close()
    elif opt=="--outputfile":
        OMET="FILE"
        try:
            out=open(arg,'wb')
        except IOError:
            print("ERROR: Could not open output file.")
            close()
#make sure we were given a file
if len(args)==0:
    print("ERROR: no files given!")
    close()
#and not too many
if len(args)>1:
    print("ERROR: too many files given!")
    close()
#open the program
try:
    p=open(args[0],'rb')
except IOError:
    print("ERROR: could not open file \""+args[0]+"\"!")
    close()
#parse the program
try:
    #get the byte width
    BYTEWIDTH=ord(p.read(1))
except ValueError:
    print("ERROR: program is empty!")
    close()
#state map
states=[]
#read first state
s=p.read(2*BYTEWIDTH+2)
while len(s)==2*BYTEWIDTH+2:
    #get info from the state
    try:
        cmd=("LFT","RGT","INC","DEC","INP","OUT","NOP","HLT")[s[0]]
    except IndexError:
        print("ERROR: unrecognized command byte \""+s[0]+"\"")
        close()
    bar=s[1]
    jmps=s[2:]
    jmp=[jmps[:len(jmps)//2],jmps[len(jmps)//2:]]
    jmp[0]=int.from_bytes(jmp[0], byteorder='big', signed=False)
    jmp[1]=int.from_bytes(jmp[1], byteorder='big', signed=False)
    #add it to the list
    states.append(State(cmd, bar, jmp))
    #read states by chucks
    s=p.read(2*BYTEWIDTH+2)
#run the program!!
tape=[0]
ip=0
state=0
while True:
    try:
        runCmd(states[state].cmd)
    except IndexError:
        print("ERROR: There is no state \""+str(state)+"\"")
        close(2)
    if states[state].bar<=tape[ip]:
        state=states[state].jmp[1]
    else:
        state=states[state].jmp[0]