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#!/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.

#

"""

HORD encapsulator

"""

import sys

import os

import xstruct

HEADER = """little:

    char tag[4]            /* 'HORD' */

    uint8_t version        /* version */

    uint8_t encoding       /* encoding */

    uint32_t header_size   /* header size */

    uint64_t payload_size  /* payload size */

"""

HORD_LSB = 1

def align_up(size, alignment):

    "Align upwards to a given alignment"

    return (((size) + ((alignment) - 1)) & ~((alignment) - 1))

def usage(prname):

    "Print usage syntax"

    print prname + " <ALIGNMENT> <FS_IMAGE> <HORD_IMAGE>"

def main():

    if (len(sys.argv) < 4):

        usage(sys.argv[0])

        return

    if (not sys.argv[1].isdigit()):

        print "<ALIGNMENT> must be a number"

        return

    align = int(sys.argv[1], 0)

    if (align <= 0):

        print "<ALIGNMENT> must be positive"

        return

    fs_image = os.path.abspath(sys.argv[2])

    if (not os.path.isfile(fs_image)):

        print "<FS_IMAGE> must be a file"

        return

    inf = file(fs_image, "rb")

    outf = file(sys.argv[3], "wb")

    header = xstruct.create(HEADER)

    header_size = header.size()

    payload_size = os.path.getsize(fs_image)

    header_size_aligned = align_up(header_size, align)

    payload_size_aligned = align_up(payload_size, align)

    header.tag = "HORD"

    header.version = 1

    header.encoding = HORD_LSB

    header.header_size = header_size_aligned

    header.payload_size = payload_size_aligned

    outf.write(header.pack())

    outf.write(xstruct.create("little: padding[%d]" % (header_size_aligned - header_size)).pack())

    outf.write(inf.read())

    padding = payload_size_aligned - payload_size

    if (padding > 0):

        outf.write(xstruct.create("little: padding[%d]" % padding).pack())

    inf.close()

    outf.close()

if __name__ == '__main__':

    main()