simd_r_drive_entry_handle/
debug_assert_aligned.rs

1/// Debug-only pointer alignment assertion that is safe to export.
2///
3/// Why this style:
4/// - We need to re-export a symbol other crates can call, but we do not
5///   want benches or release builds to pull in debug-only deps or code.
6/// - Putting `#[cfg(...)]` on the function itself makes the symbol
7///   vanish in release/bench. Callers would then need their own cfg
8///   fences, which is brittle across crates.
9/// - By keeping the function always present and gating only its body,
10///   callers can invoke it unconditionally. In debug/test it asserts;
11///   in release/bench it compiles to a no-op.
12///
13/// Build behavior:
14/// - In debug/test, the inner block runs and uses `debug_assert!`.
15/// - In release/bench, the else block keeps the args "used" so the
16///   function is a true no-op (no codegen warnings, no panic paths).
17///
18/// Cost:
19/// - Inlining plus the cfg-ed body means zero runtime cost in release
20///   and bench profiles.
21///
22/// Usage:
23/// - Call anywhere you want a cheap alignment check in debug/test,
24///   including from other crates that depend on this one.
25#[inline]
26pub fn debug_assert_aligned(ptr: *const u8, align: usize) {
27    #[cfg(any(test, debug_assertions))]
28    {
29        debug_assert!(align.is_power_of_two());
30        debug_assert!(
31            (ptr as usize & (align - 1)) == 0,
32            "buffer base is not {}-byte aligned",
33            align
34        );
35    }
36
37    #[cfg(not(any(test, debug_assertions)))]
38    {
39        // Release/bench: no-op. Keep args used to avoid warnings.
40        let _ = ptr;
41        let _ = align;
42    }
43}
44
45/// Debug-only file-offset alignment assertion that is safe to export.
46///
47/// Same rationale as `debug_assert_aligned`: keep a stable symbol that
48/// callers can invoke without cfg fences, while ensuring zero cost in
49/// release/bench builds.
50///
51/// Why not a module-level cfg or `use`:
52/// - Some bench setups compile with `--all-features` and may still pull
53///   modules in ways that trip cfg-ed imports. Gating inside the body
54///   avoids those hazards and keeps the bench linker happy.
55///
56/// Behavior:
57/// - Debug/test: checks that `off` is a multiple of the configured
58///   `PAYLOAD_ALIGNMENT`.
59/// - Release/bench: no-op, arguments are marked used.
60///
61/// Notes:
62/// - This asserts the *derived start offset* of a payload, not the
63///   pointer. Use the pointer variant to assert the actual address you
64///   hand to consumers like Arrow.
65#[inline]
66pub fn debug_assert_aligned_offset(off: u64) {
67    #[cfg(any(test, debug_assertions))]
68    {
69        use crate::constants::PAYLOAD_ALIGNMENT;
70
71        debug_assert!(
72            PAYLOAD_ALIGNMENT.is_power_of_two(),
73            "PAYLOAD_ALIGNMENT must be a power of two"
74        );
75        debug_assert!(
76            off.is_multiple_of(PAYLOAD_ALIGNMENT),
77            "derived payload start not {}-byte aligned (got {})",
78            PAYLOAD_ALIGNMENT,
79            off
80        );
81    }
82
83    #[cfg(not(any(test, debug_assertions)))]
84    {
85        // Release/bench: no-op. Keep arg used to avoid warnings.
86        let _ = off;
87    }
88}
simd_r_drive_entry_handle/debug_assert_aligned.rs

simd_r_drive_entry_handle/
debug_assert_aligned.rs
