pyleb128

Powerful little-endian base-128 encoding/decoding library for Python 3.

Supports the following types:

• Unsigned LEB128
• Signed LEB128
• Unsigned LEB128 +1 (ULEB128P1)

Note

The LEB classes all inherit from int and have all the operations implemented. The type of the result from any int operation will always be the type of the lhs. If the lhs is an int, then the type is an int. If the lhs is a LEB type, then the resulting type is a LEB.

Installing

python -m pip install -U pyleb128

Example Usage

from pyleb128 import uleb128, sleb128

# unsigned
print(uleb128(0xffff).size)  # 2
print((uleb128(0xffff) * 2).encoded)  # b'\xfe\xff\x07'
print(uleb128.decode(b'\xff\xff\x03'))  # 65535
print(uleb128.decode(b'\xff\xff\x03').encoded)  # b'\xff\xff\x03'
print(uleb128.decode(b'\xff\xff\x03', p1=True))  # decode with as ULEB128P1

# signed
print(sleb128.decode(b'\xf3\xff\xff\xff\x0f'))  # -13
print(uleb128.decode(b'\xf3\xff\xff\xff\x0f').encoded)  # b'\xf3\xff\xff\xff\x0f'

# can decode from a binary stream, too:
import io

stream = io.BytesIO(b'\xff\xff\x03') 
print(uleb128.decode_stream(stream, p1=True))