stropt

stropt - struct optimizer- is a tool that can be used to obtain statistics about C aggregate types (struct, unions), like their size, alignment and total padding bytes.

This can prove useful to optimize the layout of a struct in your code.

stropt offers statistics on a C aggregate type (structs, unions), passed as a parameter, and contained in a source file to be provided to the tool.

More info on C structs and how compilers handle them in this article here.

Build

git clone https://github.com/Abathargh/stropt
go build

// or, if you want to install this directly
go install github.com/Abathargh/stropt

Usage

You can either use stropt by passing the source to analyze as a string:

stropt "struct meta" "struct meta { int a; double d; float f[100];};"

Or you can pass a file in which the definition is contained:

// test.c
struct test {
  const char * str;
  unsigned char flag;
  const int * const iptr;
  char c;
};

stropt -file test.c "struct test" 

Optimizing hints

You can use -optimize to get hints on how to optimize your struct layout, so that its size is minimized:

Note that specifying -verbose will print information about the layout of fields that are structs themselves.

Specify platform-specific alignment and sizes

A series of flags can be used to specify the size of base types on your platform (e.g. char, short, int, long, etc.). These are the following:

• ptr
• enum
• char
• short
• int
• long
• longlong
• float
• double
• longdouble

Use them as such:

stropt -ptr 4,4 -file test.c "struct test"

License

GPL 2.0

The output of this tool is not covered by this license, and any code produced by it has the same license of the one used to generate it.