metadata

uxnmeta

@@ -0,0 +1,112 @@
+#!/usr/bin/env python
+#
+# extract metadata from uxn rom files.
+#
+# see https://wiki.xxiivv.com/site/manifest.html
+#
+# (also converts the icon to a monochrome BMP file.)
+
+from sys import argv, exit
+
+# convert two bytes into an address, subtracting for zero page
+def toaddr(x, y):
+    return x * 256 + y - 256
+
+# parse null-terminated string
+def parsestr(data, start):
+    end = start + data[start:].find(b'\0')
+    return end + 1, data[start:end].decode('ascii')
+
+# convert 64x64 icn to bmp
+# since we are always dealing with a 1-bit 64x64
+# image we can just hardcode the BMP header data
+def tobmp(icn):
+    bmp =  b"BM"               #  0: bitmap file
+    bmp += b"\x20\x10\x00\x00" #  2: file size: 4128 (32 + 4096)
+    bmp += b"\x00\x00"         #  6: reserved: 0
+    bmp += b"\x00\x00"         #  8: reserved: 0
+    bmp += b"\x20\x00\x00\x00" # 10: pixel data offset: 32
+    bmp += b"\x0c\x00\x00\x00" # 14: header size: 12
+    bmp += b"\x40\x00"         # 18: width in pixels: 64
+    bmp += b"\x40\x00"         # 20: height in pixels: 64
+    bmp += b"\x01\x00"         # 22: color planes: 1
+    bmp += b"\x01\x00"         # 24: bits per pixel: 1
+    bmp += b"\xff\xff\xff"     # 26: color 0
+    bmp += b"\x00\x00\x00"     # 29: color 1
+                               # 32: start of pixel data
+
+    # ICN is composed of a grid of 8x8 tiles. for BMP we need
+    # to create 64 rows of 64 pixels each.
+    rows = []
+    for offset in range(0, 512, 64):
+        for y in range(0, 8):
+            rows.append([])
+            for x in range(0, 64, 8):
+                rows[-1].append(icn[offset + y + x])
+    for row in reversed(rows):
+        bmp += bytes(row)
+    return bmp
+
+# read the icon from the given binary data and address
+def parseicon(path, data, pos0):
+    if len(data[pos0:]) < 512:
+        print('needed 512 bytes, only had %d' % len(data[pos0:]))
+    icn = data[pos0:pos0+512]
+    bmp = tobmp(icn)
+    return bmp
+
+# parse the metadata from the given binary data and address
+def parsemeta(path, data, pos0):
+    a,b,c,d = data[pos0:pos0+4]
+    endaddr = toaddr(a, b)
+    iconaddr = toaddr(c, d)
+    pos1, name = parsestr(data, pos0 + 4)
+    pos2, version = parsestr(data, pos1)
+    pos3, desc = parsestr(data, pos2)
+    pos4, author = parsestr(data, pos3)
+    if pos4 != endaddr:
+        print('%s: data ended by %04x but expected %04x' % (path, pos4, endaddr))
+    bmp = parseicon(path, data, iconaddr)
+    return {'name': name, 'version': version, 'desc': desc, 'author': author, 'icon': bmp}
+
+# parse metadata from the given uxn rom
+def parse(path):
+    f = open(path, 'rb')
+    data = f.read()
+    f.close()
+
+    if len(data) < 6:
+        print("%s: file too small (%d bytes)" % (path, len(data)))
+        exit(1)
+
+    a,x,y,d,e,f = data[:6]
+    if a != 0xa0 or d != 0x80 or e != 0xf0 or f != 0x37:
+        print('%s: no metadata detected' % path)
+        exit(1)
+
+    return parsemeta(path, data, toaddr(x, y))
+
+# go for it!
+def main():
+    if len(argv[1:]) != 1:
+        print('usage: %s ROMFILE' % argv[0])
+        exit(1)
+
+    path = argv[1]
+    meta = parse(path)
+
+    iconpath = path + '.bmp'
+    with open(iconpath, 'wb') as f:
+        f.write(meta['icon'])
+
+    print('%s:' % path)
+    print('  Name:        %s' % meta['name'])
+    print('  Version:     %s' % meta['version'])
+    print('  Description: %s' % meta['desc'])
+    print('  Author:      %s' % meta['author'])
+    print('')
+    print('  Icon:        %s' % iconpath)
+    print('')
+
+if __name__ == "__main__":
+    main()