pv command, but reading compressed files

zpv.sh

#!/bin/bash

set -euo pipefail

if [ $# -lt 1 ]; then
	echo "Usage: $0 [pv options] <file>"
	exit 1
fi

argv=("$@")
file="${argv[${#argv[@]}-1]}"
argv[${#argv[@]}-1]='-'

size_xz() {
	xz -vl "$1" \
		| grep -m1 "Uncompressed size:" \
		| grep -o '(.* B)' \
		| sed 's/[(), B]//g'
}

size_gz() {
	gzip -l "$1" \
		| tail -n 1 \
		| awk '{print $2}'
}

size_zstd() {
	zstd -d <"$1" | wc -c | awk '{print $1}'
}

if [[ $file == *.xz ]]; then
	size="$(size_xz "$file")"
	cmd=(xz -d)
elif [[ $file == *.gz ]]; then
	size="$(size_gz "$file")"
	cmd=(gzip -d)
elif [[ $file == *.zst ]]; then
	size="$(size_zstd "$file")"
	cmd=(zstd -d)
else
	echo "Unrecognized file extension: $file"
	exit 1
fi

<"$file" "${cmd[@]}" | pv --size "$size" "${argv[@]}"