lspci emulation for Busybox lspci

lspci-emul-opt.sh

#!/bin/sh
# use option -nn to show both textual and numeric ID's (names & numbers)
i=/usr/share/misc/pci.ids.gz
if [ ! -s $i ]; then
	busybox lspci
else
	pciids=$(mktemp)
	zcat $i | sed '/^#/d; /^\t\t/d' > $pciids
	classes=$(mktemp)
	sed -n '/^C /,$p' $pciids > $classes
	busybox lspci | \
	while read a b c id; do
		echo -n "$a"

		awk -va=${c:0:2} -vb=${c:2:2} -vo="$1" '
		{
			if ($1 == "C" && $2 == a) class = substr($0, 5)
			if (class != "" && $1 == b) { class = substr($0, 5); exit }
		}
		END {
			if (o == "-nn")
				printf("%s [%s%s]: ", class, a, b)
			else
				printf("%s: ", class)
		}' $classes

		sed -n "/${id:0:4}/,/^[^\t]/p" $pciids | \
		awk -vh=${id:0:4} -vl=${id:5:4} -vo="$1" '
		{
			if ($1 == h)
				{ m = substr($0, 7); next }
			else if ($1 == l)
				{ d = substr($0, 7); exit }
		}
		END {
			if (o == "-nn") nn = " [" h ":" l "]";
			printf("%s%s%s\n", m, d, nn);
		}'
	done
	rm $pciids $classes
fi

lspci-emul-orig.sh

#!/bin/sh
busybox lspci | while read a b c id ; do
		echo -n "$a "
		if [ $b != "Class" ] || [ ! -s /usr/share/misc/pci.ids.gz ]; then
			echo "$b $c $id"
			continue
		fi
		zcat /usr/share/misc/pci.ids.gz | \
		awk -va=${c:0:2} -vb=${c:2:2} -vh=${id:0:4} -vl=${id:5:4} '{
	if ($1 == "C" && $2 == a) class=substr($0,5)
	if (class != "" && $1 == b) { class=substr($0,5); exit }
	if (substr($0,1,4) == h) m=substr($0,7)
	else if (m == "") next
	else if (substr($0,2,4) == l) { name=m substr($0,7); m="" }
	else if ($1 == h && $2 == l) { name=m substr($0,14); m="" }
} END { print class ": " name }'
	done

results.txt

lspci --version
lspci version 3.2.1

time lspci
real    0m 0.03s
user    0m 0.02s
sys     0m 0.00s

time lspci-emul-orig.sh
real    0m 3.50s
user    0m 3.43s
sys     0m 0.17s

time lspci-emul-opt.sh
real    0m 0.73s
user    0m 0.73s
sys     0m 0.11s