Wad reader

lazyish_wad_reader2.py

import sys
import logging
import struct
logging.basicConfig(level=logging.DEBUG)
logger =logging.getLogger(__name__)

def get_int(data):
    return struct.unpack("<I", data)[0]

DIR_HEADER_SIZE=12
def get_header(data_stream):
    retval = {}
    header = data_stream.read(DIR_HEADER_SIZE)
    retval.update(dict(wad_type = header[:4]))
    retval.update(dict(num_entries = get_int(header[4:8])))
    retval.update(dict(directory_absolute_location = get_int(header[8:DIR_HEADER_SIZE])))
    retval.update(dict(data_size = retval['directory_absolute_location'] - DIR_HEADER_SIZE))
    return retval

def get_data(data_stream, directory_location):
    return { "data": data_stream.read(directory_location)}
    
def get_directory_entries(data_stream):
    while True:
        retval = {}    
        item = data_stream.read(16)
        if len(item) != 16:
            raise StopIteration
        retval.update(dict(start = get_int(item[:4])))
        retval.update(dict(size = get_int(item[4:8])))
        retval.update(dict(name = item[8:16]))
        yield retval
        

def build_directory(file_name):
    with open(file_name, 'r') as wad_file:
        header = get_header(wad_file)
        wad_file.seek(header['directory_absolute_location'])
        return [ i for i in get_directory_entries(wad_file)]

directory = build_directory(sys.argv[1])
print len(directory)
def extract_data(file_name, directory, lumps_of_interest=None):
    retval = {}
    with open(file_name, 'r') as wad_file:
        for lump in directory:
            if lumps_of_interest and lump['start'] not in lumps_of_interest:
                continue
            wad_file.seek(lump['start'])
            data = wad_file.read(lump['size'])
            #print lump, len(data)
            retval[lump['name'].strip('\0')] = data
    return retval
            
E1M1_lumps = [ 67500, 68880, 75532, 94972, 96840, 105624, 106572, 113180, 115392, 116296 ]
data = extract_data(sys.argv[1], directory, E1M1_lumps)
for key, value in data.items():
    print key, len(value)

import io
def get_vertexes(byte_stream):
    while True:
        byte_elem = byte_stream.read(4)
        if len(byte_elem) != 4:
            raise StopIteration
        yield struct.unpack("<hh", byte_elem)
        
def get_linedefs(byte_stream):
    while True:
        byte_elem = byte_stream.read(14)
        if len(byte_elem) != 14:
            raise StopIteration
        retval = []
        #yield [ ord(i) for i in byte_elem] # 16 bytes
        with io.BytesIO(byte_elem) as b:
            retval.append(struct.unpack("<hh", b.read(4)))
            # ignore the rest
            yield retval
            # a = struct.unpack("<hh", byte_elem[:4])
            # a = struct.unpack("<hh", byte_elem[:4])
            # a = struct.unpack("<hh", byte_elem[:4])
            # a = struct.unpack("<hh", byte_elem[:4])

def get_dims(vertex_data):
    lower_left = None
    with io.BytesIO(vertex_data) as bio:
        low = min(v[0] for v in get_vertexes(bio))
        bio.seek(0)
        left = min(v[1] for v in get_vertexes(bio))
        bio.seek(0)
        high = max(v[0] for v in get_vertexes(bio))
        bio.seek(0)
        right = max(v[1] for v in get_vertexes(bio))
    lower_left = (low, left)
    upper_right = (high, right)
    return lower_left,upper_right

lower_left, upper_right =  get_dims(data['VERTEXES'])
import svgwrite
dwg = svgwrite.Drawing('test.svg', size = (abs(upper_right[0]), abs(upper_right[1])))
verts = []
with io.BytesIO(data['VERTEXES']) as bio:
    for v in get_vertexes(bio):
        x, y =  (v[0] - lower_left[0])/10.0, (v[1] - lower_left[1])/10.0
        verts.append((x,y))
        dwg.add(svgwrite.shapes.Rect((x,y),size=(0.5,0.5), stroke='#333', stroke_width=3))
print len(verts),'LENG!'

count = 0
with io.BytesIO(data['LINEDEFS']) as bio:
    for v in get_linedefs(bio):
        count += 1
        a,b =  v[0]
        print v, verts[a], verts[b]
        dwg.add(dwg.line(verts[a],verts[b],stroke='#333', stroke_width=1))
print count
dwg.save()
# some node fun.
with io.BytesIO(data['NODES']) as nodedata:
    idx = 0
    while True:
        dat = nodedata.read(8)
        if not dat:
            break
        print idx,struct.unpack("<hhhh", dat)
        idx +=1
        nodedata.read(16)
        nodedata.read(4)

wad_reader.py

import sys
import logging
import struct
logging.basicConfig(level=logging.DEBUG)
logger =logging.getLogger(__name__)

# def getbytes(data):
#     return struct.unpack('<I', data)[0]
DIR_HEADER_SIZE=12
def get_directory(file_stream):
    '''
    0x00-0x03  string "PWAD" or "IWAD", defines whether the WAD is a PWAD or an IWAD
    0x04-0x07	An integer specifying the number of entries in the directory
    0x08-0x0b	An integer holding a pointer to the location of the directory
    '''
    retval = {}
    directory_raw = file_stream.read(DIR_HEADER_SIZE)
    retval.update({"wad_type": directory_raw[:4]})
    retval.update({"num_entries": getbytes(directory_raw[4:8])[0]})
    retval.update({"location": getbytes(directory_raw[8:12])[0]})
    data_size = retval['location'] - DIR_HEADER_SIZE
    retval.update({'data': file_stream.read(data_size)})
    return retval

def get_lump(file_stream):
    lump = file_stream.read(16)
    if len(lump) != 16:
        return None
    retval = {}
    retval.update({"start": getbytes(lump[0:4])[0] - DIR_HEADER_SIZE})
    retval.update({"size": getbytes(lump[4:8])[0]})
    name = lump[8:16]
    retval.update({"name": name})
    return retval

def getbytes(data):
    return struct.unpack("<I", data)

with open(sys.argv[1],'rb') as wadfile:
    directory_data = get_directory(wadfile)
    print directory_data['wad_type'], directory_data['location'], directory_data['num_entries'], len(directory_data['data'])
    while True:
        lump = get_lump(wadfile)
        if not lump:
            break
        data = directory_data['data'][lump['start']:lump['start']+lump['size']]
        print lump, len(data)
        if lump['name'] == 'VERTEXES':
            print struct.unpack("<hh", data[0:4])
            print struct.unpack("<hh", data[4:8])
            # print struct.unpack("<hh", data[0:4])
            # print struct.unpack("<hh", data[0:4])
    # lump_start = getbytes(data[0:4])
    # lump_size = getbytes(data[4:8])
    # lump_name = data[8:16]
    

get_linedefs gets linedef packets of 14 (doom version) and only uses the first 4 bytes (start vertex index -end vertex index)

Code then ignores the rest for now

From http://zdoom.org/wiki/Linedef... read it as follows : 0-1 means byte 0 AND byte 1, 2-3 means byte 2 AND byte 3 etc.
Bytes Data type Description
0-1 Unsigned short Beginning vertex
2-3 Unsigned short Ending vertex
4-5 Unsigned short Flags
6-7 Unsigned short Line type
8-9 Unsigned short Sector tag
10-11 Unsigned short Right sidedef - 0xFFFF means there is no sidedef
12-13 Unsigned short Left sidedef - 0xFFFF means there is no sidedef

Rendered file: