icydb-core 0.277.2

//! Module: index::key::codec::bounds
//! Responsibility: byte-size bounds/constants for index-key framing.
//! Does not own: parsing logic or semantic key construction.
//! Boundary: consumed by codec encode/decode helpers.

use crate::db::{
    index::{IndexId, key::codec::IndexKey},
    key_taxonomy::{
        COMPOSITE_PRIMARY_KEY_MAX_SIZE, INDEX_COMPONENT_MAX_SIZE, INDEX_KEY_MAX_SIZE,
        INDEX_KEY_PREFIX_SIZE,
    },
};

pub(super) const KEY_KIND_TAG_SIZE: usize = 1;
pub(super) const COMPONENT_COUNT_SIZE: usize = 1;
pub(super) const SEGMENT_LEN_SIZE: usize = 2;
pub(super) const INDEX_ID_SIZE: usize = IndexId::STORED_SIZE_USIZE;
pub(super) const KEY_PREFIX_SIZE: usize = INDEX_KEY_PREFIX_SIZE;

#[expect(clippy::cast_possible_truncation)]
impl IndexKey {
    pub(crate) const MAX_COMPONENT_SIZE: usize = INDEX_COMPONENT_MAX_SIZE;
    pub(crate) const MAX_PK_SIZE: usize = COMPOSITE_PRIMARY_KEY_MAX_SIZE;

    const MIN_SEGMENT_SIZE: usize = 1;

    /// Maximum on-disk size in bytes (stable, protocol-level bound)
    pub(crate) const MAX_STORED_SIZE_BYTES: u64 = INDEX_KEY_MAX_SIZE as u64;

    /// Maximum in-memory size (for bounds checks)
    pub(crate) const MAX_STORED_SIZE_USIZE: usize = Self::MAX_STORED_SIZE_BYTES as usize;

    /// Minimum encoded size for an empty index key.
    pub(crate) const MIN_STORED_SIZE_BYTES: u64 =
        (KEY_PREFIX_SIZE + SEGMENT_LEN_SIZE + Self::MIN_SEGMENT_SIZE) as u64;

    /// Minimum encoded size for an empty index key.
    pub(crate) const MIN_STORED_SIZE_USIZE: usize = Self::MIN_STORED_SIZE_BYTES as usize;

    #[must_use]
    pub(crate) fn wildcard_low_pk() -> Vec<u8> {
        vec![0]
    }

    #[must_use]
    pub(crate) fn wildcard_high_pk() -> Vec<u8> {
        // Every canonical scalar/composite primary-key tag is strictly below 0xFF.
        vec![0xFF]
    }
}