Sequence and array operations

Operations common to sequences and arrays

Base traits

Some operations are common to both sequences and arrays by design, and can be used as the interoperability base between the two types of collections. These operations are the following:

len: gives the length of an array or sequence;
iter: iterates over the content of the array or sequence (unsafe in hacspec but can be used for implementing primitives)
create: creates a sequence or array and initializes the elements to the default value (0 for arithmetic types);
update_slice, update and update_start: produce a new sequence or array with modified contents.

Both sequences and arrays implement indexing with any type of unsigned public integer.

Chunking

Both arrays and sequences support chunking with methods like:

num_chunks and num_exact_chunks (whole or partial blocks);
get_chunk, get_exact_chunk and get_remainder_chunk;
set_chunk and set_exact_chunk.

The read operations borrow the sequence or array, but the write operations create a new sequence or array.

Conversions

Sequences and arrays can be created from other types via methods like:

from_public_slice and from_slice;
from_vec and from_native_slice;
from_public_seq and from_seq (to convert a seq into an array of the correct size);
from_string and from_hex for byte or hex strings (hex only for u8 sequences and arrays).

Secrecy

The methods prefixed by public performs an element-wise classification of the data under the hood.

Some methods have two versions: an owned and a non-owned version, depending on whether the self argument is consumed or not by the method. This distinction is useful to avoid unnecessary copies and thus be more performant.

Array-specific operations

Since array length is known statically, new does not take any argument, same as length. slices of arrays become Seq.

Sequence-specific operations

Sequences can be extended (by creating a new sequence under the hood) with push or concat. Sequences can also be sliced with slice.

hacspec