Crate init_space 

init_space_derive

A procedural macro that automatically calculates the space required to store a struct in Solana programs (or Borsh-serialized data).

• Computes size for fixed types like u8, u64, bool, etc.
• Supports dynamic types like String and Vec<u8> by requiring a #[max_len = N] attribute.

Example

use init_space_derive::InitSpace;
use borsh::{BorshSerialize, BorshDeserialize};

#[derive(BorshSerialize, BorshDeserialize, InitSpace)]
pub struct Movie {
    pub title: u64,
    pub rating: u8,
    #[max_len = 1000]
    pub description: Vec<u8>,
}

let space_needed = Movie::space();
assert_eq!(space_needed, 13 + 1004); // 13 for fixed, 4+1000 for Vec

Derive Macros

InitSpace