[Feature Request] support base64 in `checksum` output as well as hex and dec

[MrCreosote]

Hello, thanks for this package.

It'd be very useful if the checksum CLI could output a base64 encoded CRC as well as hex/dec as that would allow for direct comparison with AWS S3 objects uploaded with aws-cli, since by default that stores a base64 encoded CRC64/NVME checksum.

Thanks very much in advance for your magnanimous consideration

[MrCreosote]

Workaround

$checksum -a CRC-64/NVME -f cromwell-44.jar | xxd -rp | base64
YI7K6rgiSXg=

[LFenske]

Don't use this package to compare with AWS S3 crc results: they don't always match. I have seen two instances of files where the CRC-64/NVME results don't match the AWS results. The results from the awscrt Python library do match the checksums computed by AWS S3 in all the samples I've tried. I tried "checksum -a CRC-64/NVME" on both an Intel Xeon processor and on a Raspberry Pi 5 (Arm), and they match each other, but not AWS, in those instances.

[nkr0]

I have an idea why S3 results are sometimes not a match. AWS uses a fixed width checksum and this program does not pad hex output with leading zeros when necessary.

crc-fast-rust/src/bin/checksum.rs

Line 367 in 3a853cc

OutputFormat::Hex => println!("{:#x?}", checksum),

For e.g., this is invalid for AWS

$ echo "0xcac33b2946eebed" | xxd -r | base64
ysM7KUbuvg==

AWS expects

$ echo "0x0cac33b2946eebed" | xxd -r | base64
DKwzspRu6+0=