ICO reader in Python demo

icoreader.py

import struct
import ctypes
import re

user32 = ctypes.WinDLL(r'C:\Windows\System32\user32.dll')

icofile = r'<filepath_to_your_icofile>' # set your file name!!!
print(icofile)
with open(icofile, 'rb') as f:
	data = f.read()
	print(len(data)) # validation: must be > 6

# https://en.wikipedia.org/wiki/ICO_(file_format)
# ICONDIRENTRY structure - 16 bytes
#     0 - width
#     1 - height
#     2 - colors
#   6-7 - bits per pixel
#  8-11 - size of image data
# 12-15 - offset of image data
ICONDIRENTRY = '@BBBBHHII'
ICOHEADER = '@IH'
isignature,icount = struct.unpack(ICOHEADER, data[0:6])
print(isignature == 0x10000) # ICO format validation
print(icount) # icon amount

icons = [] # icon storage
diroffset = range(6,16*icount,16)
for k,i in enumerate(diroffset):
	w,h,colors,_,_,bpp,l,dataoffset = struct.unpack(ICONDIRENTRY, data[i:i+16])
	if 0 == w : w = 256
	if 0 == h : h = 256
	imgbytes = data[dataoffset:(dataoffset+l)]
	hicon = user32.CreateIconFromResourceEx(imgbytes, l, True, 0x30000, w, h, 0)

	icons.append({
		"Handle" : hicon, # pri ID for an icon
		"Index"  : k,
		"Width"  : w,
		"Height" : h,
		"Colors" : colors,
		"Bpp"    : bpp,
		"Length" : l,
		"Bytes"  : imgbytes
	})


#print(icons)
# simple output formatter
if (len(icons) > 0):
	header = "    Handle","Index","Width","Height","Colors","Bpp","Length"
	hdelim = [re.sub('\S', '-', n) for n in header]
	print(" ".join(header))
	print(" ".join(hdelim))
	
fmt = "{0:>{1}}"
for i in icons:
	print(
		fmt.format(i['Handle'],10),
		fmt.format(i['Index'],5),
		fmt.format(i['Width'],5),
		fmt.format(i['Height'],6),
		fmt.format(i['Colors'],6),
		fmt.format(i['Bpp'],3),
		fmt.format(i['Length'],6)
	)