Crate fixed_str

A fixed–capacity, null–padded UTF‑8 string type for predictable layout and safe truncation.

FixedStr<N> always stores exactly N bytes in a [u8; N] array. The visible content is defined as the bytes up to the first null byte (\0), which is used for comparisons, hashing, and display.

Behavior

• Shorter input: Input that is shorter than N is null‑padded to fill the buffer.
• Longer input: Input that exceeds N is safely truncated at the last valid UTF‑8 boundary.
• Null byte in input: If a null byte is present in the input, the effective string ends there, and any subsequent bytes are ignored.

Philosophy

• String-first semantics: The type treats the content as a genuine string rather than merely a raw byte array.
• Lossy by default: Truncation prioritizes preserving valid UTF‑8 over preserving every byte.
• Strict by choice: Methods like TryFrom, the builder (FixedStrBuf), and unsafe functions provide stricter control when needed.
• Const-ready: Use FixedStr::new_const for compile-time construction, which performs silent truncation.

Also included:

• FixedStrBuf<N>: A builder for incrementally constructing FixedStr values with boundary-aware methods such as try_push_str() and push_str_lossy().
• Optional integrations for serde, binrw, and support for no_std environments.

Re-exports

pub use effective_bytes::EffectiveBytes;

pub use effective_bytes::EffectiveBytesIter;

pub use fs_buffer::FixedStrBuf;

pub use fs_core::FixedStr;

pub use fs_error::FixedStrError;

pub use string_helpers::copy_into_buffer;

pub use string_helpers::dump_as_hex;

pub use string_helpers::fast_format_hex;

pub use string_helpers::find_first_null;

pub use string_helpers::find_valid_boundary;

pub use string_helpers::find_valid_utf8_len;

pub use string_helpers::panic_on_zero;

pub use string_helpers::truncate_utf8_lossy;

pub use string_helpers::BufferCopyMode;

Modules

effective_bytes

Exposes the effective (non‑zero) bytes of a FixedStr.

fs_buffer

Provides the builder type FixedStrBuf for constructing fixed‑capacity strings.

fs_core

Contains the core implementation of the FixedStr type.

fs_error

Defines custom error types for the FixedStr library.

fs_impl

Implements various trait implementations for FixedStr.

serialize_ext

Provides optional integrations for binary and serialization support (binrw and serde).

string_helpers

Contains helper functions for byte copying, UTF‑8 boundary detection, and hex formatting.