Struct WriteRange 

pub struct WriteRange {
    pub account_index: u8,
    pub offset: u32,
    pub size: u32,
}

One allowed write range on one instruction account.

account_index is the position in the instruction’s account list (the same index handed to Context::account). Offsets are absolute within the account data, including any layout header bytes, the same convention the segment access primitives use.

Fields

account_index: u8

Instruction account-list index this range applies to.

offset: u32

Absolute byte offset of the allowed range.

size: u32

Byte size of the allowed range. WriteRange::whole_account uses u32::MAX, which contains any request on the account (account data is capped far below 4 GiB).

Implementations

impl WriteRange

pub const fn new(account_index: u8, offset: u32, size: u32) -> Self

Allow writes to [offset, offset + size) on account_index.

pub const fn whole_account(account_index: u8) -> Self

Allow whole-account writes on account_index (what a plain mut declaration grants).

pub const fn tail_from(account_index: u8, offset: u32) -> Self

Allow writes to the open-ended tail [offset, +inf) on account_index, the grant a growable Seq<T> tail needs.

size is u32::MAX, so contains admits any sub-range starting at or after offset regardless of how large the account grows (the account data cap is far below 4 GiB, and contains widens to u64 so offset + u32::MAX cannot wrap).

Crucially this is not a whole-account grant when offset != 0: allows_whole_account_write requires a range containing [0, u32::MAX), and a tail range that starts past the fixed head fails that test. So the fixed head stays byte-protected and CPI writable-meta delegation stays refused, while the tail region past offset remains freely writable and growable.

pub const fn contains(&self, offset: u32, size: u32) -> bool

Whether [offset, offset + size) is fully contained in this range. Widened to u64 so offset + size cannot wrap.

Trait Implementations

impl Clone for WriteRange

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for WriteRange

impl Debug for WriteRange

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for WriteRange

impl PartialEq for WriteRange

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for WriteRange