#!/usr/bin/env python
#
# Copyright (c) 2008 Martin Decky
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# - Redistributions in binary form must reproduce the above copyright
#   notice, this list of conditions and the following disclaimer in the
#   documentation and/or other materials provided with the distribution.
# - The name of the author may not be used to endorse or promote products
#   derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
"""
TMPFS creator
"""

import sys
import os
import struct
import xstruct

HEADER = xstruct.convert("little: "
	"char[5]  /* 'TMPFS' */ "
)

DENTRY = xstruct.convert("little: "
	"uint8_t   /* NONE, FILE or DIRECTORY */ "
	"uint32_t  /* filename length */ "
)

SIZE = xstruct.convert("little: "
	"uint32_t  /* file size */ "
)

DENTRY_NONE = 0
DENTRY_FILE = 1
DENTRY_DIRECTORY = 2

def usage(prname):
	"Print usage syntax"
	print prname + " <PATH> <IMAGE>"

def recursion(root, outf):
	"Recursive directory walk"
	
	for name in os.listdir(root):
		canon = os.path.join(root, name)
		
		if (os.path.isfile(canon)):
			outf.write(struct.pack(DENTRY, DENTRY_FILE, len(name)))
			outf.write(xstruct.little_string(name))
			size = os.path.getsize(canon)
			rd = 0;
			outf.write(struct.pack(SIZE, size))
			
			inf = file(canon, "r")
			while (rd < size):
				data = inf.read(4096);
				outf.write(data)
				rd += len(data)
			inf.close()
		
		if (os.path.isdir(canon)):
			outf.write(struct.pack(DENTRY, DENTRY_DIRECTORY, len(name)))
			outf.write(xstruct.little_string(name))
			recursion(canon, outf)
			outf.write(struct.pack(DENTRY, DENTRY_NONE, 0))

def main():
	if (len(sys.argv) < 3):
		usage(sys.argv[0])
		return
	
	path = os.path.abspath(sys.argv[1])
	if (not os.path.isdir(path)):
		print "<PATH> must be a directory"
		return
	
	outf = file(sys.argv[2], "w")
	
	outf.write(struct.pack(HEADER, "TMPFS"))
	recursion(path, outf)
	outf.write(struct.pack(DENTRY, DENTRY_NONE, 0))

	outf.close()
		
if __name__ == '__main__':
	main()