#! /usr/bin/python

"""
	Name		: T2INF.py (was T2Peg400.py)
	Author		: David Boddie <davidb@mcs.st-and.ac.uk>
	Created		: Mon 28th August 2000
	Last updated	: Wed 22nd November 2000
	Purpose		: Convert Slogger T2* files to files on a disc.
	WWW		: http://www.david.boddie.net/Software/Tape2Disc/

	License :

	This program is freeware. This means that it can be copied as long as it
	remains complete (in the form it was originally distributed) and is not
	charged for. If you want to use it in your own software then contacting
	me may prove beneficial since I may be able to provide a more up-to-date
	version.

	This program, although designed to extract all files from tape images,
	is intended for the extraction of users' own files from such images.

	Using this program to extract software which has been encoded in an
	image may be contravening the conditions of that software's license.

	You use this program entirely at your own risk.

	All copyrights and trademarks acknowledged.
"""

import sys, string, os

def	read_block(in_f):

	global eof
	
	# Read the alignment character
	align = in_f.read(1)

	if not align:
		eof = 1
		return ("", 0, 0, "", 0)

	align = ord(align)^90

	if align == 0x2b:
		eof = 1
		return ("", 0, 0, "", 0)

	# Default file attributes
	name = ""
	load = 0
	exec_addr = 0
	
	while 1:
		c = in_f.read(1)
		if not c:
			eof = 1
			return (name, 0, 0, "", 0)

		c = chr(ord(c)^90)

		if ord(c) == 0:
			break

		name = name + c


	load = (ord(in_f.read(1))^90)+((ord(in_f.read(1))^90) << 8)+((ord(in_f.read(1))^90) << 16)+((ord(in_f.read(1))^90) << 24)

	exec_addr = (ord(in_f.read(1))^90)+((ord(in_f.read(1))^90) << 8)+((ord(in_f.read(1))^90) << 16)+((ord(in_f.read(1))^90) << 24)

	block_number = (ord(in_f.read(1))^90)+((ord(in_f.read(1))^90) << 8)

	if verbose == 1:
		if block_number == 0:
			print
			print name,
		print string.upper(hex(block_number)[2:]),

	block_length = (ord(in_f.read(1))^90)+((ord(in_f.read(1))^90) << 8)

	if block_length==0:
		return (name, load, exec_addr, "", block_number)
	
	block_flag = ord(in_f.read(1))

	next_addr = (ord(in_f.read(1))^90)+((ord(in_f.read(1))^90) << 8)

	header_crc = (ord(in_f.read(1))^90)+((ord(in_f.read(1))^90) << 8)

        in_f.seek(2, 1)

	if list_files == 0:
		block = ""
		for i in range(0,block_length):
			byte = ord(in_f.read(1)) ^ 90
			block = block + chr(byte)
	else:
		in_f.seek(block_length, 1)
		block = ""
	
	block_crc = (ord(in_f.read(1))^90)+((ord(in_f.read(1))^90) << 8)
	
	return (name, load, exec_addr, block, block_number)


def get_leafname(path):

	pos = string.rfind(path, os.sep)
	if pos != -1:
		return path[pos+1:]
	else:
		return path


# Main program

version = "0.14 (Wed 22nd November 2000)"
syntax = "Syntax: T2INF.py [-l] [-v] <tape file> <destination path> [-name <stem>]"

arguments = len(sys.argv)
args = sys.argv[1:]

# If there are no arguments then print the help text
if len(args) < 2:
	print syntax
	print
	print "T2INF version "+version
	print
	print "This program attempts to decode a tape file, <tape file>, produced by the"
	print "Slogger T2 series of ROMs for the Acorn Electron microcomputer and save the"
	print "files contained to the directory given by <destination path>."
	print "The load and execution addresses, and the file lengths are written to .inf"
	print "files corresponding to each file extracted." 
	print
	print "The options perform the following functions:"
	print
	print "-l              Lists the names of the files as they are extracted."
	print
	print "-name <stem>    Writes files without names in the format <stem><number>"
	print "                with <number> starting at 1."
	print
	print "-v              Verbose output."
	print
	sys.exit()

# Determine the platform on which the program is running

sep = os.sep

if sys.platform == "RISCOS":
	suffix = "/"
elif sys.platform == "DOS":
	suffix = "."
else:
	suffix = "."

# List files
if (args.count("-l") > 0):
	list_files = 1
	# Find the argument and remove it
	while (args.count("-l") > 0):
		args.remove("-l")
else:
	list_files = 0

# Verbose output
if (args.count("-v") > 0):
	verbose = 1
	# Find the argument and remove it
	while (args.count("-v") > 0):
		args.remove("-v")
else:
	verbose = 0

# Stem for unknown filenames
new = []
stem = "noname"
found = 0
i = 0
while i < len(args):
	if (args[i] == "-name") & (found == 0):
		try:
			stem = args[i+1]
			found = 1
		except:
			print syntax
			print
			sys.exit()

		i = i + 2
	else:
		new.append(args[i])
		i = i + 1

args = new

# Input file and output path specified?
if (list_files == 0) & (len(args) < 2):
	print syntax
	print
	sys.exit()

if (list_files == 1) & (len(args) < 1):
	print syntax
	print
	sys.exit()


# Open the input file
try:
	in_f = open(args[0], "rb")
except IOError:
	print "The input file, "+args[0]+" could not be found."
	sys.exit()

if list_files == 0:

	# Get the leafname of the output path
	leafname = get_leafname(args[1])

	# See if the output directory exists
	try:
		os.listdir(args[1])
	except:
		try:
			os.mkdir(args[1])
			print "Created directory "+args[1]
		except:
			print "Directory "+leafname+" already exists."
			sys.exit()

in_f.seek(5, 1)		# Move to byte 5 in the T2 file

eof = 0			# End of file flag
out_file = ""		# Currently open file as specified in the block
write_file = ""		# Write the file using this name
file_length = 0		# File length
first_file = 1

# List of files already created
created = []

# Unnamed file counter
n = 1

while 1:
	# Read block details
	try:
		name, load, exec_addr, block, block_number = read_block(in_f)
	except IOError:
		print "Unexpected end of file"
		sys.exit()

	if list_files == 0:
		# Not listing the filenames

		if eof == 1:
			# Close the current output file
			out.close()
	
			# Write the file length information to the relevant file
			inf.write(string.upper(hex(file_length)[2:]+"\n"))
			inf.close()
			break
	
	#	# Either force new file or name in block is not the current name used
	#	if (write_file=="") | (name != out_file):
	#
	#		# New file, so close the last one (if there was one)
	#		if write_file != "":
	#			# Close the current output file
	#			out.close()
	#
	#			# Write the file length information to the relevant file
	#			inf.write(string.upper(hex(file_length)[2:]+"\n"))
	#			inf.close()
	
		# New file (block number is zero) or no previous file
		if (block_number == 0) | (first_file == 1):
	
			# Set the new name of the file
			out_file = name
			write_file = name
	
			# Open the new file with the new name
	
			if (write_file in created):
				write_file = write_file+"-"+str(n)
				n = n + 1
	
			if (write_file == ""):
				write_file = stem+str(n)
				n = n + 1
	
			# New file, so close the last one (if there was one)
			if first_file == 0:
				# Close the previous output file
				out.close()
	
				# Write the file length information and the NEXT parameter
				# to the previous .inf file
				inf.write(string.upper(hex(file_length)[2:]+"\tNEXT $."+write_file+"\n"))
				inf.close()
			else:
				first_file = 0

			# Reset the file length
			file_length = 0

			try:
				out = open(args[1]+sep+write_file, "wb")
			except IOError:
				# Couldn't open the file
				write_file = stem+str(n)
				n = n + 1
				try:
					out = open(args[1]+sep+write_file, "wb")
				except IOError:
					print "Couldn't open the file %s." % args[1]+sep+write_file
					sys.exit()
	
			# Add file to the list of created files
			created.append(write_file)
	
			try:
				inf = open(args[1]+sep+write_file+suffix+"inf", "w")	# Open information file
			except IOError:
				print "Couldn't open the information file %s." % args[1]+sep+write_file+suffix+"inf"
				sys.exit()
	
			# Write the load and execution information to the relevant file
			inf.write("$."+write_file+"\t"+string.upper(hex(load)[2:])+"\t"+string.upper(hex(exec_addr)[2:])+"\t")
	

		if block != "":
	
			# Write the block to the relevant file
			out.write(block)
	
			file_length = file_length + len(block)
	else:
		# Listing the filenames
		if eof == 1:
			break

		if (verbose == 0) & (block_number == 0):
			print name



# Close the input file
in_f.close()

# Exit
sys.exit()