1.fas文件称为一种快速加载文件，这种文件省去了加载时的翻译时间，所以相对较快一些.
2.fas文件格式大体如下：
垃圾数据或其他
fas文件标识
data1size
(ascii)
‘$’
data1(不确定是否加密)
'$'
data2size(ascii)
'$'
data2(加密)
keysize(1字节)
keydata
'$'
编译时间及其他数据
这里面fas文件标识类似 FAS4-FILE ; Do not change it!
python实现：
import os
def mixor(datapl,mipl):
for a in datapl:
if len(mipl) < len(datapl)+1:
mipl += mipl
jiemapl = ""
for b in range(len(datapl)):
newpl = ord(datapl[b]) ^ ord(mipl[b]) ^ ord(mipl[b+1])
jiemapl += chr(newpl)
ret = jiemapl
return ret
fr = open('acad.fas', 'rb')
data = fr.read()
fr.close()
headflag = 'FAS4-FILE ; Do not change it!'
aa = data.find(headflag)
if(aa == -1):
print 'error in find FAS4'
sleep(4)
data = data[aa-3 : ]
i1 = data.find('$')
tmp = data[34 : i1]
ee = tmp.find('\n')
tlst = tmp[ : ee]
dfg = int(tlst)
toupl = data[ : i1+1]
if(dfg != 1):
ee1 = data[34 : i1]
i1sta = i1+1
de13 = ee1.find('\n')
da0lst = ee1[ : de13]
num = int(da0lst)
i1end = i1sta + num
i2 = i1end+1
strdat0 = data[i1sta : i1end]
tmpl = data[i2 : i2+50]
i3 = i2 + tmpl.find('$') + 1;
tmpl1 = data[i2+2 : i3]
de32 = tmpl1.find(' ')
da1lst = tmpl1[ : de32]
num1 = int(da1lst)
i3end = i3 + num1
strdat1 = data[i3 : i3end]
print i3
keylen = ord(data[i3end])
keyend = i3end + keylen + 1
keylst = data[i3end+1 : keyend]
lastlst = data[keyend : ]
zjlst = data[i2-1 : i3]
## nstrlst0 = mixor(strdat0, keylst)
nstrlst1 = mixor(strdat1, keylst)
fpl1 = toupl + strdat0 + zjlst + nstrlst1 + str(keylen) + keylst + lastlst
fw = open('a11.fas', 'wb')
fw.write(fpl1)
fw.close()