bytes_terminate() benchmark for the Kaitai Struct Python runtime library: https://github.com/kaitai-io/kaitai_struct_python_runtime/blob/d457617/kaitaistruct.py#L447

bench_bytes_terminate.py

"""
Usage:

    $ richbench --markdown .

You need to install https://pypi.org/project/richbench/ first:

    $ python -m pip install -U richbench
"""

import random

TERM_HALFWAY = 1
TERM_END = 2
TERM_MISSING = 3

# Settings

TERM_POS = TERM_MISSING
INCLUDE_TERM = False
WORKLOAD_SIZE = 128 * 1024
NUM_ITERS = 20000


def bytes_terminate(data, term, include_term):
    new_data, term_byte, _ = data.partition(bytes((term,)))
    if include_term:
        new_data += term_byte
    return new_data


def bytes_terminate_new(data, term, include_term):
    term_index = data.find(term)  # KaitaiStream.byte_array_index_of(data, term)
    if term_index == -1:
        return data[:]
    return data[:term_index + (1 if include_term else 0)]


term = random.randrange(256)
repl = 0x00
if repl == term:
    repl = 0xff
buf = bytearray(random.randbytes(WORKLOAD_SIZE))
for i, b in enumerate(buf):
    if b == term:
        buf[i] = repl
if TERM_POS == TERM_HALFWAY:
    buf[len(buf) // 2] = term
elif TERM_POS == TERM_END:
    buf[-2] = term
elif TERM_POS == TERM_MISSING:
    pass
buf = bytes(buf)

if TERM_POS == TERM_HALFWAY:
    exp = len(buf) // 2 + (1 if INCLUDE_TERM else 0)
elif TERM_POS == TERM_END:
    exp = len(buf) - 2 + (1 if INCLUDE_TERM else 0)
elif TERM_POS == TERM_MISSING:
    exp = len(buf)

act = len(bytes_terminate(buf, term, INCLUDE_TERM))
assert act == exp, 'expected {} but got {}'.format(exp, act)
act = len(bytes_terminate_new(buf, term, INCLUDE_TERM))
assert act == exp, 'expected {} but got {}'.format(exp, act)


def old():
    for _ in range(NUM_ITERS):
        bytes_terminate(buf, term, INCLUDE_TERM)


def new():
    for _ in range(NUM_ITERS):
        bytes_terminate_new(buf, term, INCLUDE_TERM)


__benchmarks__ = [
    (old, new, "old vs new"),
]

'''
pp@DESKTOP-89OPGF3:/mnt/c/temp/kaitai_struct/runtime/python$ python3 --version
Python 3.10.12

pp@DESKTOP-89OPGF3:/mnt/c/temp/kaitai_struct/runtime/python$ sed -n '19,22p;23q' bench_bytes_terminate.py
TERM_POS = TERM_HALFWAY
INCLUDE_TERM = False
WORKLOAD_SIZE = 128 * 1024
NUM_ITERS = 20000
pp@DESKTOP-89OPGF3:/mnt/c/temp/kaitai_struct/runtime/python$ richbench --markdown --repeat 10 .
                                 Benchmarks, repeat=10, number=5

|  Benchmark | Min     | Max     | Mean    | Min (+)         | Max (+)         | Mean (+)        |
|------------|---------|---------|---------|-----------------|-----------------|-----------------|
| old vs new | 0.376   | 0.385   | 0.379   | 0.204 (1.85x)   | 0.212 (1.82x)   | 0.208 (1.82x)   |

pp@DESKTOP-89OPGF3:/mnt/c/temp/kaitai_struct/runtime/python$ sed -n '19,22p;23q' bench_bytes_terminate.py
TERM_POS = TERM_HALFWAY
INCLUDE_TERM = True
WORKLOAD_SIZE = 128 * 1024
NUM_ITERS = 20000
pp@DESKTOP-89OPGF3:/mnt/c/temp/kaitai_struct/runtime/python$ richbench --markdown --repeat 10 .
                                 Benchmarks, repeat=10, number=5

|  Benchmark | Min     | Max     | Mean    | Min (+)         | Max (+)         | Mean (+)        |
|------------|---------|---------|---------|-----------------|-----------------|-----------------|
| old vs new | 0.560   | 0.569   | 0.564   | 0.208 (2.69x)   | 0.214 (2.65x)   | 0.210 (2.68x)   |

pp@DESKTOP-89OPGF3:/mnt/c/temp/kaitai_struct/runtime/python$ sed -n '19,22p;23q' bench_bytes_terminate.py
TERM_POS = TERM_END
INCLUDE_TERM = False
WORKLOAD_SIZE = 128 * 1024
NUM_ITERS = 20000
pp@DESKTOP-89OPGF3:/mnt/c/temp/kaitai_struct/runtime/python$ richbench --markdown --repeat 10 .
                                 Benchmarks, repeat=10, number=5

|  Benchmark | Min     | Max     | Mean    | Min (+)         | Max (+)         | Mean (+)        |
|------------|---------|---------|---------|-----------------|-----------------|-----------------|
| old vs new | 0.445   | 0.459   | 0.451   | 0.450 (-1.01x)  | 0.459 (-1.00x)  | 0.454 (-1.01x)  |

pp@DESKTOP-89OPGF3:/mnt/c/temp/kaitai_struct/runtime/python$ sed -n '19,22p;23q' bench_bytes_terminate.py
TERM_POS = TERM_END
INCLUDE_TERM = True
WORKLOAD_SIZE = 128 * 1024
NUM_ITERS = 20000
pp@DESKTOP-89OPGF3:/mnt/c/temp/kaitai_struct/runtime/python$ richbench --markdown --repeat 10 .
                                 Benchmarks, repeat=10, number=5

|  Benchmark | Min     | Max     | Mean    | Min (+)         | Max (+)         | Mean (+)        |
|------------|---------|---------|---------|-----------------|-----------------|-----------------|
| old vs new | 0.928   | 0.944   | 0.937   | 0.460 (2.02x)   | 0.466 (2.02x)   | 0.462 (2.03x)   |

pp@DESKTOP-89OPGF3:/mnt/c/temp/kaitai_struct/runtime/python$ sed -n '19,22p;23q' bench_bytes_terminate.py
TERM_POS = TERM_MISSING
INCLUDE_TERM = False
WORKLOAD_SIZE = 128 * 1024
NUM_ITERS = 20000
pp@DESKTOP-89OPGF3:/mnt/c/temp/kaitai_struct/runtime/python$ richbench --markdown --repeat 10 .
                                 Benchmarks, repeat=10, number=5

|  Benchmark | Min     | Max     | Mean    | Min (+)         | Max (+)         | Mean (+)        |
|------------|---------|---------|---------|-----------------|-----------------|-----------------|
| old vs new | 0.145   | 0.149   | 0.147   | 0.143 (1.01x)   | 0.147 (1.01x)   | 0.144 (1.02x)   |

pp@DESKTOP-89OPGF3:/mnt/c/temp/kaitai_struct/runtime/python$ sed -n '19,22p;23q' bench_bytes_terminate.py
TERM_POS = TERM_MISSING
INCLUDE_TERM = True
WORKLOAD_SIZE = 128 * 1024
NUM_ITERS = 20000
pp@DESKTOP-89OPGF3:/mnt/c/temp/kaitai_struct/runtime/python$ richbench --markdown --repeat 10 .
                                 Benchmarks, repeat=10, number=5

|  Benchmark | Min     | Max     | Mean    | Min (+)         | Max (+)         | Mean (+)        |
|------------|---------|---------|---------|-----------------|-----------------|-----------------|
| old vs new | 0.149   | 0.154   | 0.151   | 0.144 (1.04x)   | 0.153 (1.01x)   | 0.147 (1.03x)   |
'''