`hex.read_nth_byte`¶

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

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

Signature¶

def read_nth_byte dst, ptr, index < hex.pointers.nth_ptr { ... }

Defined in hex/pointers/read_pointers.fj — lines 88–91 (view on GitHub).

Complexity¶

Time: w(3@+10.25) + 9@+13 // for w=64
Space: w(3@+69) + 9@+72 // 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 read_nth_byte dst, ptr, index < hex.pointers.nth_ptr {
    .ptr_index hex.pointers.nth_ptr, ptr, index
    .read_byte dst, hex.pointers.nth_ptr
}

Depends on¶

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