decompile.py

#!/usr/bin/python
# -*- coding: utf-8 -*-

from __future__ import with_statement
import sys
import struct
import StringIO



# kcm.bin file format
# Source:
#  build/tools/kcm/kcm.cpp

# ***** HEADER *****
# Offset    | Description
# 0x00-0x07 | The ascii value "keychar" including the null character
# 0x08-0x0b | Endian marker (0x12345678)
# 0x0c-0x0f | version (2)
# 0x10-0x13 | key count (n)
# 0x14-0x17 | keyboard type (NUMERIC [1], Q14 [2], QWERTY [3], etc.)
# 0x18-0x1f | Padding
# 0x20-.... | entries (16 bytes × key count)

# ***** ENTRIES *****
# Offset    | Description
# 0x00-0x03 | KeyEvent name
# 0x04-0x05 | Display Label
# 0x06-0x07 | Number
# 0x08-0x09 | Base
# 0x0a-0x0b | Shift
# 0x0c-0x0d | Alt
# 0x0e-0x0f | Shift+Alt

# Keycode Labels
# source:
#  frameworks/base/include/ui/KeycodeLabels.h
keycodes={"SOFT_LEFT": 1, "SOFT_RIGHT": 2, "HOME": 3, "BACK": 4,
          "CALL": 5, "ENDCALL": 6, "0": 7, "1": 8, "2": 9, "3": 10,
          "4": 11, "5": 12, "6": 13, "7": 14, "8": 15, "9": 16,
          "STAR": 17, "POUND": 18, "DPAD_UP": 19, "DPAD_DOWN": 20,
          "DPAD_LEFT": 21, "DPAD_RIGHT": 22, "DPAD_CENTER": 23,
          "VOLUME_UP": 24, "VOLUME_DOWN": 25, "POWER": 26,
          "CAMERA": 27, "CLEAR": 28, "A": 29, "B": 30, "C": 31,
          "D": 32, "E": 33, "F": 34, "G": 35, "H": 36, "I": 37,
          "J": 38, "K": 39, "L": 40, "M": 41, "N": 42, "O": 43,
          "P": 44, "Q": 45, "R": 46, "S": 47, "T": 48, "U": 49,
          "V": 50, "W": 51, "X": 52, "Y": 53, "Z": 54, "COMMA": 55,
          "PERIOD": 56, "ALT_LEFT": 57, "ALT_RIGHT": 58,
          "SHIFT_LEFT": 59, "SHIFT_RIGHT": 60, "TAB": 61, "SPACE": 62,
          "SYM": 63, "EXPLORER": 64, "ENVELOPE": 65, "ENTER": 66,
          "DEL": 67, "GRAVE": 68, "MINUS": 69, "EQUALS": 70,
          "LEFT_BRACKET": 71, "RIGHT_BRACKET": 72, "BACKSLASH": 73,
          "SEMICOLON": 74, "APOSTROPHE": 75, "SLASH": 76, "AT": 77,
          "NUM": 78, "HEADSETHOOK": 79, "FOCUS": 80, "PLUS": 81,
          "MENU": 82, "NOTIFICATION": 83, "SEARCH": 84,
          "MEDIA_PLAY_PAUSE": 85, "MEDIA_STOP": 86, "MEDIA_NEXT": 87,
          "MEDIA_PREVIOUS": 88, "MEDIA_REWIND": 89,
          "MEDIA_FAST_FORWARD": 90, "MUTE": 91, "PAGE_UP": 92,
          "PAGE_DOWN": 93, "PICTSYMBOLS": 94, "SWITCH_CHARSET": 95, }

rkeycodes={}
for (k,v) in keycodes.items(): rkeycodes[v] = k

keyboardTypes = {1: 'NUMERIC', 2: 'Q14', 3: 'QWERTY',}
def getKBType(n):
    if n in keyboardTypes:
        return keyboardTypes[n]
    raise ValueError

MAGIC = 'keychar\x00'

def checkHeader(buf):
    """
    Takes the first 32 bytes of the file, confirms it is a valid keymap header
    Returns endian marker for struct, entry count, and keyboard type.
    """
    (magic, marker) = struct.unpack('8s4s20x', buf)
    if magic != MAGIC:
        raise ValueError
    endian = None
    if marker == '\x12\x34\x56\x78': # big
        endian = '>'
    elif marker == '\x78\x56\x34\x12': # little
        endian = '<'
    else:
        raise ValueError

    (version, count, kbtype) = struct.unpack(endian+'12x3i8x', buf)
    if version != 2:
        raise ValueError
    kbtype = getKBType(kbtype)
    return (endian, count, kbtype)

class KR:
    def __init__(self, values):
        self.values = values
        (self.keycode,
         self.display,
         self.number,
         self.base,
         self.shift,
         self.alt,
         self.shiftalt) = values

    def __repr__(self):
        return "KR: KeyCode %i; Base: %i" % (self.keycode, self.base)

    def _fmt(self, val):
        if 0x20 < val <= 0x7e:
            return "'%s'" % chr(val)
        else:
            return '0x%X' % val

    def printKR(self):
        fmt = (rkeycodes[self.keycode],)
        fmt += tuple([self._fmt(x) for x in self.values[1:]])
        return ("%-15s%-10s%-10s%-10s%-10s%-10s%-10s" % fmt).strip()

def parseKR(buf, endian):
    """
    Parses a 16-byte key row entry
    """
    return KR(struct.unpack(endian+'I6H', buf))

def decompileKCM(In, Out):
    header = In.read(32)
    endian, count, ktype = checkHeader(header)
    Out.write("[type=%s]\n" % ktype)
    #          0         1         2         3         4         5         6         7
    #          01234567890123456789012345678901234567890123456789012345678901234567890123
    Out.write("# keycode      Display   Number    Base      Shift     Alt       Shift+Alt\n")
    for i in range(count):
        kr = parseKR(In.read(16), endian)
        Out.write(kr.printKR()+"\n")

if __name__ == '__main__':
    if len(sys.argv) != 3:
        print """usage: kcm [INPUT] [OUTPUT]
        INPUT   compiled keycharmap file, - for STDIN
        OUTPUT  keycharmap file, - for STDOUT
        """
        exit(-1)
    In, Out = sys.argv[1:3]

    output = StringIO.StringIO()
    if In == '-':
        decompileKCM(sys.stdin, output)
    else:
        with open(sys.argv[1],'rb') as f:
            decompileKCM(f, output)

    if Out == '-':
        sys.stdout.write(output.getvalue())
    else:
        with open(sys.argv[2],'w') as f:
            f.write(output.getvalue())