Package {awscrt}

Title: Hardware-Accelerated 'CRC Checksums' from the AWS Common Runtime
Version: 0.1.1
Description: Computes 'CRC32', 'CRC32C' and 'CRC64NVME' 'checksums' using the 'aws-checksums' library from the 'AWS' Common Runtime, with runtime dispatch to hardware instructions ('SSE4.2', 'PCLMULQDQ', 'AVX-512', 'ARMv8' 'CRC' and 'PMULL') and a portable software fallback.
License: Apache License (≥ 2)
URL: https://github.com/paws-r/aws-crt-r, https://paws-r.r-universe.dev/awscrt
BugReports: https://github.com/paws-r/aws-crt-r/issues
Encoding: UTF-8
Suggests: testthat (≥ 3.0.0)
Config/testthat/edition: 3
SystemRequirements: GNU make, C compiler
Config/roxygen2/version: 8.1.0
NeedsCompilation: yes
Packaged: 2026-10-18 17:30:32 UTC; Dyfan.Jones
Author: Dyfan Jones [aut, cre], Amazon.com, Inc. or its affiliates [cph] (Author of the bundled aws-checksums and aws-c-common libraries)
Maintainer: Dyfan Jones <dyfan.r.jones@gmail.com>
Repository: CRAN
Date/Publication: 2026-10-28 11:40:16 UTC

awscrt: Hardware-Accelerated CRC Checksums from the AWS Common Runtime

Description

Computes CRC32, CRC32C and CRC64NVME checksums using the 'aws-checksums' library from the AWS Common Runtime ('CRT'), with runtime dispatch to hardware instructions (SSE4.2, PCLMULQDQ, AVX-512, ARMv8 CRC and PMULL) and a portable software fallback. Results are returned as big-endian raw vectors, matching the bytes the 'S3' flexible-checksum headers are built from, and can be chained for incremental hashing.

Author(s)

Maintainer: Dyfan Jones dyfan.r.jones@gmail.com

Authors:

Other contributors:

See Also

Useful links:

CRC checksums

Description

Compute CRC32, CRC32C (Castagnoli) and CRC64NVME checksums with the aws-checksums library from the AWS Common Runtime.

Usage

crc32(x, previous = NULL, raw = FALSE)

crc32c(x, previous = NULL, raw = FALSE)

crc64nvme(x, previous = NULL, raw = FALSE)

Arguments

x

A raw vector, or a single string (converted to UTF-8 bytes).

previous

NULL (start a new checksum) or the raw checksum returned by a previous call with raw = TRUE.

raw

If FALSE (the default), return the checksum as a hexadecimal string. If TRUE, return it as a big-endian raw vector.

Details

Hardware instructions are used when the CPU supports them (SSE4.2, PCLMULQDQ and AVX-512 on x86-64, CRC and PMULL on arm64), otherwise a portable software implementation is used.

Value

A hexadecimal string, or with raw = TRUE a big-endian raw vector (length 4 or 8).

Examples

crc32c("123456789")
crc64nvme("123456789")
crc32c("123456789", raw = TRUE)

# Incremental
part1 <- crc32(charToRaw("1234"), raw = TRUE)
identical(crc32(charToRaw("56789"), part1), crc32("123456789"))

CRC checksums of a file

Description

Like crc32(), crc32c() and crc64nvme() but reading the file in chunks, so files larger than memory can be checksummed.

Usage

crc32_file(path, previous = NULL, raw = FALSE, chunk_size = 1048576L)

crc32c_file(path, previous = NULL, raw = FALSE, chunk_size = 1048576L)

crc64nvme_file(path, previous = NULL, raw = FALSE, chunk_size = 1048576L)

Arguments

path

Path to a file.

previous

NULL (start a new checksum) or the raw checksum returned by a previous call with raw = TRUE.

raw

If FALSE (the default), return the checksum as a hexadecimal string. If TRUE, return it as a big-endian raw vector.

chunk_size

Number of bytes to read at a time. Default chunk size (1 MiB)

Value

A hexadecimal string, or with raw = TRUE a big-endian raw vector, see checksums.

Examples

f <- tempfile()
writeLines("hello", f)
crc32c_file(f)
unlink(f)

CPU features used for hardware acceleration

Description

CPU features used for hardware acceleration

Usage

cpu_features()

Value

A named logical vector of the CPU features detected at runtime by the AWS Common Runtime. Features that do not apply to the current architecture are FALSE.

Examples

cpu_features()