How to read photoshop .act files with Python

I was looking for a way to read the Photoshop's color palette files.

As of yet there is no answer here, so I'd like to share my solution.

Photoshop stores color values as hexadecimals, with info at the end of the file and here's how you can read it with Python.

    from codecs import encode

    def act_to_list(act_file):
        with open(act_file, 'rb') as act:
            raw_data = act.read()                           # Read binary data
        hex_data = encode(raw_data, 'hex')                  # Convert it to hexadecimal values
        total_colors_count = (int(hex_data[-7:-4], 16))     # Get last 3 digits to get number of colors total
        misterious_count = (int(hex_data[-4:-3], 16))       # I have no idea what does it do
        colors_count = (int(hex_data[-3:], 16))             # Get last 3 digits to get number of nontransparent colors

        # Decode colors from hex to string and split it by 6 (because colors are #1c1c1c)               
        colors = [hex_data[i:i+6].decode() for i in range(0, total_colors_count*6, 6)]

        # Add # to each item and filter empty items if there is a corrupted total_colors_count bit        
        colors = ['#'+i for i in colors if len(i)]

        return colors, total_colors_count

Important sidenote: Adobe sometimes does weird stuff, like filling the last bits with 00ff ffff ffff, which totally ruins color amount recognition. I haven't found the documentation for the fileformat, so I don't really know what's going on there.

It seems the total_colors_count is the most reliable bit of information we have, as it is least likely to get filled with fff even if we make color tables 2 or 4 colors long, where as color_count has the tendency to be broken on less than 128 colors palette tables.