StructFx

struct-fx provides declarative pure Ruby equivalent of C++ structs. Declarations are simple:

gif = StructFx::new(data) do
    string (:format) {3}
    string (:version) {3}
    uint16 :width
    uint16 :height
end

See whole real live example:

require "struct-fx"

# Read and analyze file

File.open("./test.gif", "rb") do |io|
    data = io.read(10)
end

gif = StructFx::new(data) do
    string (:format) {3}
    string (:version) {3}
    uint16 :width
    uint16 :height
end

# Get results

p gif.length        # declared struct length is really 10 bytes

p gif.data.format   # "GIF"
p gif.data.version  # "89a"
p gif.data.width    # 32
p gif.data.height   # 32    # it's square :-)

# Change the values

gif.data.version = "87a"
gif.data.width = 128
gif.data.height = 128

gif.data.to_s       # "GIF87a\x80\x00\x80\x00"

Supported data types are:

• signed and unsigned integers (1 to 8 bytes),
• fixed-size strings (specified length),
• floats and doubles (4 and 8 bytes),
• single chars (1 byte),
• packed bytes and flag arrays (1 byte),
• skipped data blocks.

More detailed documentation is available in StructFx#declare method documentation and documentation of the BitPacker library.

1. Fork it.
2. Create a branch (git checkout -b 20101220-my-change).
3. Commit your changes (git commit -am "Added something").
4. Push to the branch (git push origin 20101220-my-change).
5. Create an Issue with a link to your branch.
6. Enjoy a refreshing Diet Coke and wait.

Copyright © 2011 Martin Kozák. See LICENSE.txt for further details.