std::bytes

std::bytes is the byte-oriented facade for allocation-free work over borrowed memory. It reuses std::arrays::ByteSlice as the concrete slice type and gives CLI/search/build tools short, stable names for common hot-path operations.

Exported API#

module std::bytes;

export type ByteSlice = std::arrays::ByteSlice;

export fn from_raw (ptr: u64, len: i64) -> ByteSlice;
export fn from_string (s: string) -> ByteSlice;

export fn memchr (haystack: ByteSlice, needle: u8) -> i64?;
export fn memmem (haystack: ByteSlice, needle: ByteSlice) -> i64?;
export fn memcmp (a: ByteSlice, b: ByteSlice) -> int;
export fn equal (a: ByteSlice, b: ByteSlice) -> bool;
export fn copy (dst: ByteSlice, src: ByteSlice) -> i64;
export fn copy_nonoverlapping (dst: ByteSlice, src: ByteSlice) -> i64;

export fn starts_with (haystack: ByteSlice, prefix: ByteSlice) -> bool;
export fn ends_with (haystack: ByteSlice, suffix: ByteSlice) -> bool;
export fn contains (haystack: ByteSlice, needle: ByteSlice) -> bool;

export fn is_ascii_alpha (b: u8) -> bool;
export fn is_ascii_digit (b: u8) -> bool;
export fn is_ascii_alnum (b: u8) -> bool;
export fn is_ascii_whitespace (b: u8) -> bool;
export fn to_ascii_lower (b: u8) -> u8;
export fn to_ascii_upper (b: u8) -> u8;
export fn ascii_equal_ignore_case (a: ByteSlice, b: ByteSlice) -> bool;
export fn find_ascii_ignore_case (haystack: ByteSlice, needle: ByteSlice) -> i64?;

Ownership#

ByteSlice is a borrowed view. None of these helpers allocate or take ownership of memory. Returned offsets are byte offsets into the input slice.

copy(dst, src) copies at most min(dst.len, src.len) bytes and returns the number of bytes copied. It is overlap-safe and may be used like a small memmove helper.

copy_nonoverlapping(dst, src) has the same count/return behavior, but its contract requires that the regions do not overlap. Use it for buffer growth and output assembly paths where the caller already knows that memcpy semantics are valid.

Relationship To std::arrays#

std::arrays::ByteSlice remains the canonical packed-byte view type used by existing OS/FFI APIs. std::bytes::ByteSlice is an alias plus a focused function surface for byte search and comparison.

Current Performance Note#

On hosted targets, memchr, memcmp, copy, and copy_nonoverlapping are backed by runtime/libc byte primitives, and memmem uses a runtime helper built from memchr plus memcmp. The public contract remains the borrowed ByteSlice contract above; applications should not import runtime or libc byte bindings directly for these common search/copy paths.