Daachorse handles a value-length pair as a pattern's output (see https://github.com/daac-tools/daachorse/blob/main/src/lib.rs#L289-L292)

In the current implementation, 31 bits and 32 bits are assigned to length and value, respectively. (1 bit is used for the flag,) But, in many cases, the assignment is too rich. For example, when the maximum length is 255, 1 byte is sufficient to represent.

If we know the maximum length and value, we can memory-efficiently store members on byte-aligned memory. For example, if a length is represented in 1 byte and a value (with flag) is represented in 3 bytes, we can interleave them in a byte array outputs as follows.

outputs[0] = length 1
outputs[1] = value 1
outputs[2] = value 1
outputs[3] = value 1
outputs[4] = length 2
outputs[5] = value 2
outputs[6] = value 2
outputs[7] = value 2
...

This branch adds the following serialization and deserialization functions for convenience.

• serialize()
• serialize_to_vec()
• deserialize_unchecked()
• deserialize_from_slice_unchecked()

Deserialization functions do not validate the given automaton, so these are defined as unsafe functions. It means that the deserialization should only be used when the source of the data is completely trusted.

serialize() and deserialize_unchecked() use traits under std::io, so these functions are unavailable in the no_std environment. For bare-metal programming, they must use serialize_to_vec() and deserialize_from_slice_unchecked() instead.

I am not sure if the following part is correct, could you check carefully? https://github.com/daac-tools/daachorse/blob/4794bcc2d3525dfcb92c93c54ff0a4185c0e7c8e/src/charwise/builder.rs#L324-L327

If users specify the large number to num_free_blocks, the capacity size will be wrapped. This branch checks the value before calculating the capacity size.

Blocked by #52

This PR divided Extra from builder.rs and generalized the auxiliary data structure in double-array construction. BuildHelper can be used in both the cases of bytewise and charwise, although I will modify charwise/builder.rs in another PR.

This branch removes the following constants:

• INIT_CAPACITY: states is initialized by with_capacity() with this value, but it is often reallocated for a large automaton. On the other hand, this capacity is too large for small devices.
• FREE_BLOCKS and FREE_STATES: Some small devices do not have enough memory, so I added an option to change these parameters.

I moved constant parameters used only in builder.rs to the file. And, FAIL_INVALID is replaced into FAIL_MAX because a default fail value can be set to zero and the constant parameter will be used only for indicating the maximum possible value.

This branch renames some functions as follows:

• Removes the prefix get_.
• Removes the prefix set_ from zero-cost functions, adds the suffix _mut, and changes to return the mutable reference.

For some structures, leave set_ for consistency.

This branch enables sparse-registry on Nightly Cargo.

The build time on Nightly is reduced as follows: https://github.com/daac-tools/daachorse/actions/runs/2660385065