Migrate all Python scripts to Python 3.

Most of them are now _mandatory_ P3 scripts, because I'm tired of
maintaining everything to be compatible with both versions.

The current exceptions are gdb.py (which has to live with whatever gdb
gives it), and kh2reg.py (which is actually designed for other people
to use, and some of them might still be stuck on P2 for the moment).

icons/macicon.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 # Generate Mac OS X .icns files, or at least the simple subformats
 # that don't involve JPEG encoding and the like.
@@ -10,6 +10,8 @@ import sys
 import struct
 import subprocess
 
+assert sys.version_info[:2] >= (3,0), "This is Python 3 code"
+
 # The file format has a typical IFF-style (type, length, data) chunk
 # structure, with one outer chunk containing subchunks for various
 # different icon sizes and formats.
@@ -33,18 +35,18 @@ def make_mono_icon(size, rgba):
               for index in range(len(rgba))]
 
     # Encode in 1-bit big-endian format.
-    data = ""
+    data = b''
     for i in range(0, len(pixels), 8):
         byte = 0
         for j in range(8):
             if pixels[i+j] >= 0x80:
                 byte |= 0x80 >> j
-        data += chr(byte)
+        data += bytes(byte)
 
     # This size-32 chunk id is an anomaly in what would otherwise be a
     # consistent system of using {s,l,h,t} for {16,32,48,128}-pixel
     # icon sizes.
-    chunkid = { 16: "ics#", 32: "ICN#", 48: "ich#" }[size]
+    chunkid = { 16: b"ics#", 32: b"ICN#", 48: b"ich#" }[size]
     return make_chunk(chunkid, data)
 
 # Mask for full-colour icons: a chunk containing an 8 bpp alpha
@@ -52,9 +54,9 @@ def make_mono_icon(size, rgba):
 def make_colour_mask(size, rgba):
     assert len(rgba) == size * size
 
-    data = "".join(map(lambda pix: chr(pix[3]), rgba))
+    data = bytes(map(lambda pix: pix[3], rgba))
 
-    chunkid = { 16: "s8mk", 32: "l8mk", 48: "h8mk", 128: "t8mk" }[size]
+    chunkid = { 16: b"s8mk", 32: b"l8mk", 48: b"h8mk", 128: b"t8mk" }[size]
     return make_chunk(chunkid, data)
 
 # Helper routine for deciding when to start and stop run-length
@@ -69,19 +71,18 @@ def runof3(string, position):
 def make_colour_icon(size, rgba):
     assert len(rgba) == size * size
 
-    data = ""
+    data = b""
 
     # Mysterious extra zero header word appearing only in the size-128
     # icon chunk. libicns doesn't know what it's for, and neither do
     # I.
     if size == 128:
-        data += "\0\0\0\0"
+        data += b"\0\0\0\0"
 
     # Handle R,G,B channels in sequence. (Ignore the alpha channel; it
     # goes into the separate mask chunk constructed above.)
     for chan in range(3):
-        pixels = "".join([chr(rgba[index][chan])
-                          for index in range(len(rgba))])
+        pixels = bytes([rgba[index][chan] for index in range(len(rgba))])
 
         # Run-length encode each channel using the following format:
         #  * byte 0x80-0xFF followed by one literal byte means repeat
@@ -98,15 +99,15 @@ def make_colour_icon(size, rgba):
                        pos < len(pixels) and
                        pixels[pos] == pixval):
                     pos += 1
-                data += chr(0x80 + pos-start - 3) + pixval
+                data += bytes(0x80 + pos-start - 3) + pixval
             else:
                 while (pos - start < 128 and
                        pos < len(pixels) and
                        not runof3(pixels, pos)):
                     pos += 1
-                data += chr(0x00 + pos-start - 1) + pixels[start:pos]
+                data += bytes(0x00 + pos-start - 1) + pixels[start:pos]
 
-    chunkid = { 16: "is32", 32: "il32", 48: "ih32", 128: "it32" }[size]
+    chunkid = { 16: b"is32", 32: b"il32", 48: b"ih32", 128: b"it32" }[size]
     return make_chunk(chunkid, data)
 
 # Load an image file from disk and turn it into a simple list of
@@ -117,10 +118,10 @@ def make_colour_icon(size, rgba):
 # here that the file is in RGBA .pam format (as mkicon.py will have
 # generated it).
 def load_rgba(filename):
-    with open(filename) as f:
-        assert f.readline() == "P7\n"
+    with open(filename, "rb") as f:
+        assert f.readline() == b"P7\n"
         for line in iter(f.readline, ''):
-            words = line.rstrip("\n").split()
+            words = line.decode("ASCII").rstrip("\n").split()
             if words[0] == "WIDTH":
                 width = int(words[1])
             elif words[0] == "HEIGHT":
@@ -135,10 +136,10 @@ def load_rgba(filename):
         assert width == height
         data = f.read()
         assert len(data) == width*height*4
-        rgba = [map(ord, data[i:i+4]) for i in range(0, len(data), 4)]
+        rgba = [list(data[i:i+4]) for i in range(0, len(data), 4)]
         return width, rgba
 
-data = ""
+data = b""
 
 # Trivial argument format: each argument is a filename prefixed with
 # "mono:", "colour:" or "output:". The first two indicate image files
@@ -157,7 +158,7 @@ for arg in sys.argv[1:]:
         else:
             assert False, "bad argument '%s'" % arg
 
-data = make_chunk("icns", data)
+data = make_chunk(b"icns", data)
 
-with open(outfile, "w") as f:
+with open(outfile, "wb") as f:
     f.write(data)

icons/mkicon.py

@@ -2,9 +2,12 @@
 
 from __future__ import division
 
+import sys
 import decimal
 import math
 
+assert sys.version_info[:2] >= (3,0), "This is Python 3 code"
+
 # Python code which draws the PuTTY icon components at a range of
 # sizes.