hex.write_nth_byte

*(ptr + index*2w)[:2] = src[:2] — write the index-th byte past *ptr.

src is a hex[:2]; ptr is a hex[:w/4]; index is a signed hex[:w/4] (may be negative). ptr, index, src are preserved.

Signature

def write_nth_byte ptr, index, src < hex.pointers.nth_ptr { ... }

Defined in hex/pointers/write_pointers.fj — lines 102–105 (view on GitHub).

Complexity

• Time: w(3@+10.25) + 17@+37     // for w=64

• Space: w(3@+69)    + 17@+200     // for w=64

See the complexity glossary for what @, w, dw, dbit, n mean.

Requires init

The following must be initialised before this macro is invoked:

• hex.init and stl.ptr_init (or stl.startup_and_init_all).

Source

Click to view the macro body

def write_nth_byte ptr, index, src < hex.pointers.nth_ptr {
    .ptr_index hex.pointers.nth_ptr, ptr, index
    .write_byte hex.pointers.nth_ptr, src
}

Depends on

• hex.ptr_index

• hex.write_byte/2

---

← Previous: hex.write_nth_hex