List layers without loading image?

Code:

#!/usr/bin/env python3



import sys





PROP_ACTIVE_LAYER = 2

PROP_VISIBLE      = 8

if __name__ == "__main__":

    filename = sys.argv[1]

    # open the file in readonly binary mode

    with open(filename, 'rb') as f:

        # go to the 30th bytes

        f.seek(30, 0)

        # read properties

        while True:

            prop_type = int.from_bytes(f.read(4), "big")

            prop_size = int.from_bytes(f.read(4), "big")

            f.read(prop_size)

            if prop_type == 0: #PROP_END

                break

        # read layers

        while True:

            next_layer_offset = int.from_bytes(f.read(8), "big")

            if not next_layer_offset: #end of layers offsets

                break;

            saved_pos = f.tell()

            f.seek(next_layer_offset + 12, 0)

            tmp = int.from_bytes(f.read(4), "big")

            name = f.read(tmp).decode("utf-8")

            print()

            print(name)

            while True:

                prop_type = int.from_bytes(f.read(4), "big")

                prop_size = int(int.from_bytes(f.read(4), "big") / 4)

                # print(prop_type, "size", prop_size)

                for i in range(prop_size):

                    lastint = int.from_bytes(f.read(4), "big")

                if prop_type == PROP_VISIBLE:

                    print("Visible? %x" % lastint)

                    break

                elif prop_type == PROP_ACTIVE_LAYER:

                    print("Active")

            f.seek(saved_pos, 0)

Code:

#!/usr/bin/env python3

import sys



PROP_ACTIVE_LAYER = 2

PROP_VISIBLE      = 8

if __name__ == "__main__":

    filename = sys.argv[1]

    # open the file in readonly binary mode

    with open(filename, 'rb') as f:

        # go to the 30th bytes

        f.seek(30, 0)

        # read properties

        while True:

            prop_type = int.from_bytes(f.read(4), "big")

            prop_size = int.from_bytes(f.read(4), "big")

            f.read(prop_size)

            if prop_type == 0: #PROP_END

                break

        # read layers

        while True:

            next_layer_offset = int.from_bytes(f.read(8), "big")

            if not next_layer_offset: #end of layers offsets

                break;

            saved_pos = f.tell()

            f.seek(next_layer_offset + 12, 0)

            name_len = int.from_bytes(f.read(4), "big")

            name0 = f.read(name_len).decode("utf-8")

            name = name0.replace('\0', '')

            print()

            print(name)

            while True:

                prop_type = int.from_bytes(f.read(4), "big")

                prop_size = int(int.from_bytes(f.read(4), "big") / 4)

                #print(prop_type, "size", prop_size)

                for i in range(prop_size):

                    lastint = int.from_bytes(f.read(4), "big")

                if prop_type == PROP_VISIBLE:

                    print("Visibility: %x" % lastint)

                    break

                elif prop_type == PROP_ACTIVE_LAYER:

                    print("Active")

            f.seek(saved_pos, 0)

Code:

#!/usr/bin/env python3

import sys



PROP_ACTIVE_LAYER = 2

PROP_VISIBLE      = 8

if __name__ == "__main__":

    filename = sys.argv[1]

    # open the file in readonly binary mode

    with open(filename, 'rb') as f:

        # go to the 30th bytes

        f.seek(30, 0)

        # read properties

        while True:

            prop_type = int.from_bytes(f.read(4), "big")

            prop_size = int.from_bytes(f.read(4), "big")

            f.read(prop_size)

            if prop_type == 0: #PROP_END

                break

        # read layers

        while True:

            next_layer_offset = int.from_bytes(f.read(8), "big")

            if not next_layer_offset: #end of layers offsets

                break;

            saved_pos = f.tell()

            f.seek(next_layer_offset + 12, 0)

            name_len = int.from_bytes(f.read(4), "big")

            name0 = f.read(name_len).decode("utf-8")

            name = name0.replace('\0', '')

            print()

            print(name)

            while True:

                prop_type = int.from_bytes(f.read(4), "big")

                prop_size = int(int.from_bytes(f.read(4), "big") / 4)

                #print(prop_type, "size", prop_size)

                for i in range(prop_size):

                    lastint = int.from_bytes(f.read(4), "big")

                if prop_type == PROP_VISIBLE:

                    print("Visi: %x" % lastint)

                elif prop_type == PROP_ACTIVE_LAYER:

                    print("Active")

                elif prop_type == 0: #PROP_END

                    break

            # hierarchy pointer:

            hptr = int.from_bytes(f.read(8), "big")

            # mask pointer:

            mptr = int.from_bytes(f.read(8), "big")

            if mptr == 0:

                has_mask = 0

            else:

                has_mask = 1

            print("Mask: " + str(has_mask))

            f.seek(saved_pos, 0)