Re: writing to binary files
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- Subject: Re: writing to binary files
- From: "Carlos" <carlos-smith@...>
- Date: 2008年4月16日 20:45:11 -0400
Here is a small lua program (made from a PIL example and some code from
teststruct.lua).
The program writes some data in a binary file.
It then read it back to verify the results.
Please test this on your computer.
This will make you sure that Lua is not the problem.
--- program
require("struct")
file = "test.bin"
fmt = "<!1bi4c2i4"
local a,b,c,d
local out = assert(io.open(file, "wb"))
for i=0,255 do
-- #x == 11
local x = struct.pack(fmt, 10, -i, 99, i)
a,b,c,d = struct.unpack(fmt,x)
print( a,b,c,d )
out:write(x)
end
assert(out:close())
local f = assert(io.open(file, "rb"))
local block = 11
while true do
local bytes = f:read(block)
if not bytes then break end
a,b,c,d = struct.unpack(fmt,bytes)
print( a,b,c,d )
for b in string.gfind(bytes, ".") do
io.write(string.format("%02X ", string.byte(b)))
end
io.write(string.rep(" ", block - string.len(bytes) + 1))
io.write(string.gsub(bytes, "%c", "."), "\n")
end
f:close()