Synopsis

CStruct is a simulation of the C language's struct.Its main purpose is to manipulate binary-data conveniently in Ruby. It can be used in:

• Binary file IO like C.
• The parameter of the OS's API.(e.g. Win32)
• Other...

Lean more: http://cstruct.rubyforge.org/

Getting Started

Install CStruct

Install CStruct is easy.

gem install cstruct

Using CStruct

Let's see an example,struct Point in C language(32-bit platform) like this:

struct Point
{
  int x;
  int y;
};

How to represent struct Point in Ruby? You can use CStruct to do it.

class Point < CStruct
  int32:x
  int32:y
end

Example:

require 'cstruct'

# struct Point in Ruby:
class Point < CStruct
 int32:x
 int32:y
end

# create a Point's instance
point = Point.new

# assign like as C language
point.x = 10
point.y = 20
puts "point.x = #{point.x},point.y = #{point.y}"

Using Win32Struct

like this:

typedef struct _OSVERSIONINFOEXA {
   DWORD dwOSVersionInfoSize;
   DWORD dwMajorVersion;
   DWORD dwMinorVersion;
   DWORD dwBuildNumber;
   DWORD dwPlatformId;
   CHAR szCSDVersion[ 128 ];
   WORD wServicePackMajor;
   WORD wReserved[2];
} OSVERSIONINFOEXA;

in Ruby:

class OSVERSIONINFOEXA < Win32Struct
   DWORD :dwOSVersionInfoSize
   DWORD :dwMajorVersion
   DWORD :dwMinorVersion
   DWORD :dwBuildNumber
   DWORD :dwPlatformId
   CHAR :szCSDVersion,[ 128 ]
   WORD :wServicePackMajor
   WORD :wServicePackMinor
   WORD :wReserved,[2]
end

Lean More

Please see also Documents and Examples.