Fast, ash-compatible reimplementation of Anthony's logcat-color.sh

logcat-color.sh

#!/bin/sh

# Colorize logcat(1) output
# Copyright 2015-2020 Rivoreo

# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:

# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE
# FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
# CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


# This is a reimplementation of Anthony Lee's logcat-color.sh, which is a
# bash(1) script, available at https://github.com/M0xkLurk3r/logcat-color
#
# Unlike Anthony Lee's implementation, this implementation is compatible with
# Almquist shell (ash), Korn shell (ksh) and of course BASH; it is also 2
# times faster than Anthony Lee's implementation in most cases.

# Benchmark (Anthony's script is named logcat-color.bash in this test):
#
# $ time bash logcat-color.bash < ~/drop/android.log > /dev/null 
# 
# real	0m29.998s
# user	0m20.436s
# sys	0m9.424s
# $ time bash logcat-color.sh < ~/drop/android.log > /dev/null 
# 
# real	0m16.722s
# user	0m14.624s
# sys	0m2.088s
# $ time dash logcat-color.sh < ~/drop/android.log > /dev/null 
# 
# real	0m20.920s
# user	0m3.412s
# sys	0m17.500s
# $ time busybox ash logcat-color.sh < ~/drop/android.log > /dev/null 
# 
# real	0m23.596s
# user	0m4.436s
# sys	0m19.144s
# $ time ksh logcat-color.sh < ~/drop/android.log > /dev/null 
# 
# real	0m5.552s
# user	0m4.296s
# sys	0m1.248s

IFS=
while read -r line; do case "$line" in
	----*)
		printf '\033[7;37m%s\033[0m\n' "$line"
		;;
	*)
		IFS=" "
		set -- $line
		if [ $# -lt 6 ]; then
			printf '%s\n' "$line"
		else
			printf '\033[0;35m%s %s\033[0m ' "$1" "$2"
			skip=0
			len=${#3}
			case $len in
				0)
					pad1="     "
					;;
				1)
					pad1="    "
					;;
				2)
					pad1="   "
					;;
				3)
					pad1="  "
					;;
				4)
					pad1=" "
					;;
				*)
					pad1=
					skip=$((len-5))
					;;
			esac
			len=${#4}
			case $len in
				0)
					pad2="     "
					;;
				1)
					pad2="    "
					;;
				2)
					pad2="   "
					;;
				3)
					pad2="  "
					;;
				4)
					pad2=" "
					;;
				*)
					pad2=
					skip=$((skip+(len-5)))
					;;
			esac
			printf '%s\033[0;32m%s\033[0m %s\033[2;32m%s\033[0m ' "$pad1" "$3" "$pad2" "$4"
			case "$5" in
				F|E)
					printf '\033[1;31m'
					;;
				W)
					printf '\033[0;33m'
					;;
				D)
					printf '\033[4;37m'
					;;
				A)
					printf '\033[0;32m'
					;;
			esac
			cut="???????????????????????????????"
			while [ $skip -gt 0 ]; do
				cut="?$cut"
				skip=$((skip-1))
			done
			printf '%s\033[0m\n' "${line#$cut}"
		fi
		IFS=
		;;
esac done