StructLayoutToolkitCore

stlcore is a minimal, high‑cohesion core library for bit‑accurate binary slicing. It provides the fundamental primitives (bits_get, bits_set, InfoSize) required to build struct layout analyzers, binary editors, protocol inspectors, and low‑level testing tools. Designed for clarity, correctness, and composability.

What You Can Do After Installing sltcore

sltcore provides a minimal and consistent bit-level abstraction layer for building higher‑level tools such as binary editors, protocol analyzers, and structured layout systems.

After installing the package, you can:

• Extract arbitrary bit ranges from a bytearray using bits_get
• Write arbitrary bit ranges into a bytearray using bits_set
• Represent sizes and offsets uniformly with InfoSize
• Build structured binary layouts on top of a stable bit‑operation core

Quick Examples: bits_get / bits_set

from sltcore.types import InfoSize, Info
from sltcore.bits import bits_get, bits_set

buf = bytearray(b"\x12\x34\x56\x78")

# Extract 4 bits at offset (1 byte, 0 bits)
value = bits_get(buf, InfoSize(1, 0), InfoSize(0, 4))
print(value.to_hex)  # 0x3

# Write 5 bits at offset (2 bytes, 3 bits)
bits_set(buf, InfoSize(2, 3), InfoSize(0, 5), 0b10101)
print(buf.hex()) # 12345578

sltcore.type.InfoSize

InfoSize is a type that represents offsets and sizes in a unified way. It supports addition and subtraction, and stores both byte and bit components.

• byte: the byte component
• bit: the bit component (0–7)

always normalized so that bit < 8

It is used for both offset and size, allowing consistent structural layout definitions.

sltcore.type.Info

Info stores an InfoSize and a raw integer value.

• The value returned by bits_get is an Info instance
• The value passed to bits_set is also an Info instance

This allows higher‑level code to treat extracted fields as structured units rather than plain integers.

sltcore.bits.bits_get

bits_get extracts a field from a bytearray using an offset and size, and returns an Info object.

Input:

• bytearray buffer
• InfoSize offset
• InfoSize size

Output:

• Info containing the extracted value and its size

sltcore.bits.bits_set

bits_set writes a value into a bytearray at the specified offset.

Input:

• bytearray buffer
• InfoSize offset
• Info value (which includes its size)

The function masks and replaces the target bit range inside the buffer.

Documentation

For detailed usage, examples, and parameter descriptions, refer to the docstrings via:

python

• help(sltcore.type.InfoSize)
• help(sltcore.type.Info)
• help(sltcore.bits.bits_get)
• help(sltcore.bits.bits_set)