jpeghex.py

"""
Tool to convert jpegs to and from editable hex files


Developed as part of effort to support LightsailA

See
http://swag.outpostbbs.net/GRAPHICS/0143.PAS.html
for information on the jpeg format

Change topdir to wherever you have the files.

Converts every file matching P0*.out.jpg into ASCII hex for editing.

Converts every file matching *.tryhex to binary .jpg to see if that works
"""
from __future__ import absolute_import, print_function, division

topdir='/Users/palmer/Desktop/lightsailA'


import os
import numpy as np
import glob
import re

__author__ = 'palmer'



segnames = {
            0x01 : "TEM",
            0xc0 : "SOF0",
            0xc1 : "SOF1",
            0xc2 : "SOF2",
            0xc3 : "SOF3",
            0xc5 : "SOF5",
            0xc6 : "SOF6",
            0xc7 : "SOF7",
            0xc9 : "SOF9",
            0xca : "SOF10",
            0xcb : "SOF11",
            0xcd : "SOF13",
            0xce : "SOF14",
            0xcf : "SOF15",
            0xc4 : "DHT",
            0xc8 : "JPG",
            0xcc : "DAC",
            0xd0 : "RST0",
            0xd1 : "RST1",
            0xd2 : "RST2",
            0xd3 : "RST3",
            0xd4 : "RST4",
            0xd5 : "RST5",
            0xd6 : "RST6",
            0xd7 : "RST7",
            0xd8 : "SOI",
            0xd9 : "EOI",
            0xda : "SOS",
            0xdb : "DQT",
            0xdc : "DNL",
            0xdd : "DRI",
            0xde : "DHP",
            0xdf : "EXP",
            0xe0 : "APP0",
            0xef : "APP15",
            0xf0 : "JPG0",
            0xfd : "JPG13",
            0xfe : "COM"
            }

def jpegsplit(bytearr):
    # Add a bogus segment header, then break into [header,contents,header,contents...]
    splits = re.split(b'(\xff[^\0])',b'\xff\xff'+bytearr)
    segs = [seghead+rest for seghead,rest in zip(splits[1::2],splits[2::2])]
    if segs[0] == b'\xff\xff':
        segs = segs[1:] # Nothing in file before first segment header
    else:
        segs[0] = segs[0][2:] # File does not start with 0xff
    return segs

def seg2line(bytearr):
    """
    Convert a segment to a line that can go into a .jpeghex file

    Format:
    F segtype explen readlen | hex
    F is '!' if something is wrong
    :param bytearr:
    :return:
    """
    explen = 0 if len(bytearr) < 4 else bytearr[2] * 256 + bytearr[3]
    readlen = len(bytearr) - 2
    try:
        segtype = segnames[int(bytearr[1])]
        if segtype.startswith('RST') :
            flag = ' '
            explen = 0
        else:
            flag = '!' if (readlen != explen) and segtype != 'SOS' else ' '
    except:
        segtype = "???"
        flag = '!'
    hexes = " ".join(["{:02x}".format(b) for b in bytearr])
    return "{:1s} {:5s} {:5d} {:5d} | {:s}".format(flag,segtype,explen,readlen,hexes)

def lines2bytes(lines):
    """
    Takes lines and returns a bytearray for the hex, where the lines are:

    # this is a comment

    anythingelse (ignored) | hex
    :param lines:
    :return:
    """
    bytearr = b''
    for l in lines:
        l = l.strip()
        try:
            if not l.startswith('#'):
                newbytes = bytearray([int(x,base=16) for x in l.split('|')[1].split() if len(x.strip()) > 0])
                bytearr += newbytes
        except:
            pass
    return bytearr


for filename in glob.glob(os.path.join(topdir,'P0*.out.jpg')):
    outfilename = filename+'.hex'
    # Don't overwrite the .hex file if it has changed more recnetly than th ejpeg
    if os.path.exists(outfilename) and os.stat(filename).st_mtime < os.stat(outfilename).st_mtime:
        continue
    bytearr = open(filename,"rb").read()
    segs = jpegsplit(bytearr)
    lines = [seg2line(seg) for seg in segs]
    open(outfilename,"w").write("\n".join(lines))

for filename in glob.glob(os.path.join('/Users/palmer/Desktop/lightsailA','*.tryhex')):
    outfilename = filename+'.jpg'
    # Don't overwrite the .jpg file if it has changed more recnetly than the tryhex
    if os.path.exists(outfilename) and os.stat(filename).st_mtime < os.stat(outfilename).st_mtime:
        continue
    lines = open(filename).readlines()
    bytearr = lines2bytes(lines)
    open(outfilename,"wb").write(bytearr)