sized_data/
lib.rs

1//! Sized data trait implementation for Solana programs using Anchor framework
2//! 
3//! This crate provides a trait and derive macro for calculating struct sizes at compile time,
4//! which is particularly useful when working with Solana account initialization.
5//!
6//! # Example
7//!
8//! ```rust
9//! use sized_data::SizedData;
10//! use anchor_lang::prelude::*;
11//!
12//! #[derive(SizedData)]
13//! pub struct UserAccount {
14//!     pub authority: Pubkey,
15//!     pub counter: u64,
16//! }
17//!
18//! #[derive(Accounts)]
19//! pub struct Initialize<'info> {
20//!     #[account(
21//!         init,
22//!         payer = user,
23//!         space = UserAccount::size_padded()
24//!     )]
25//!     pub user_account: Account<'info, UserAccount>,
26//!     #[account(mut)]
27//!     pub user: Signer<'info>,
28//!     pub system_program: Program<'info, System>,
29//! }
30//! ```
31
32use anchor_lang::prelude::Pubkey;
33
34pub use sized_data_derive::*;
35
36/// A trait for types that can calculate their size at compile time.
37///
38/// Used primarily with Anchor accounts to determine required space allocation.
39/// The trait provides two methods:
40/// - `size()`: Returns the raw size of the type
41/// - `size_padded()`: Returns the size including Anchor's 8-byte discriminator
42///
43/// # Examples
44///
45/// ```rust
46/// use sized_data::SizedData;
47/// use anchor_lang::prelude::*;
48///
49/// #[derive(SizedData)]
50/// pub struct UserAccount {
51///     pub authority: Pubkey,  // 32 bytes
52///     pub counter: u64,       // 8 bytes
53/// }
54///
55/// assert_eq!(UserAccount::size(), 40);       // Raw size
56/// assert_eq!(UserAccount::size_padded(), 48); // Including discriminator
57/// ```
58pub trait SizedData {
59    /// Returns the raw size of the type in bytes
60    fn size() -> usize;
61
62    /// Returns the size including Anchor's 8-byte discriminator
63    fn size_padded() -> usize {
64        8 + Self::size()
65    }
66}
67
68impl SizedData for u64 {
69    fn size() -> usize {
70        8
71    }
72}
73
74impl SizedData for [u8; 32] {
75    fn size() -> usize {
76        32
77    }
78}
79
80impl SizedData for Pubkey {
81    fn size() -> usize {
82        32
83    }
84}
85
86impl SizedData for u8 {
87    fn size() -> usize {
88        1
89    }
90}
sized_data/lib.rs

sized_data/
lib.rs
