#! /bin/sh
#
# Copyright (c) 2018-2025 Gavin D. Howard and contributors.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice, this
#   list of conditions and the following disclaimer.
#
# * Redistributions in binary form must reproduce the above copyright notice,
#   this list of conditions and the following disclaimer in the documentation
#   and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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#

# Tests the timeconst.bc script from the Linux kernel build.
# You can find the script at kernel/time/timeconst.bc in any Linux repo.
# One such repo is: https://github.com/torvalds/linux

script="$0"
testdir=$(dirname "$script")

outputdir=${BC_TEST_OUTPUT_DIR:-$testdir/..}

# Just print the usage and exit with an error. This can receive a message to
# print.
# @param 1  A message to print.
usage() {
	if [ $# -eq 1 ]; then
		printf '%s\n\n' "$1"
	fi
	printf 'usage: %s [timeconst_script] [exec args...]\n' "$0"
	exit 1
}

. "$testdir/../../scripts/functions.sh"

# Gets the timeconst script, which could be a command-line argument. I don't
# need to check for error because we just skip if it doesn't work.
if [ "$#" -gt 0 ]; then
	timeconst="$1"
	shift
else
	timeconst="$testdir/scripts/timeconst.bc"
fi

# Gets the executable, which could also be a command-line argument.
if [ "$#" -gt 0 ]; then
	bc="$1"
	shift
	check_exec_arg "$bc"
else
	bc="$testdir/../../bin/bc"
	check_exec_arg "$bc"
fi

out1="$outputdir/bc_outputs/bc_timeconst.txt"
out2="$outputdir/bc_outputs/bc_timeconst_results.txt"

outdir=$(dirname "$out1")

# Make sure the directory exists.
if [ ! -d "$outdir" ]; then
	mkdir -p "$outdir"
fi

base=$(basename "$timeconst")

# If the script does not exist, just skip. Running this test is not necessary.
if [ ! -f "$timeconst" ]; then
	printf 'Warning: %s does not exist\n' "$timeconst"
	printf '%s is not part of this bc because of license incompatibility\n' "$timeconst"
	printf 'Get it at https://github.com/torvalds/linux/blob/master/kernel/time/timeconst.bc\n'
	printf 'if you want to test it\n'
	printf 'Skipping...\n'
	exit 0
fi

# I use these, so unset them to make the tests work.
unset BC_ENV_ARGS
unset BC_LINE_LENGTH
unset DC_ENV_ARGS
unset DC_LINE_LENGTH

printf 'Running %s...' "$base"

# Get a list of numbers. Funny how bc can help with that.
nums=$(printf 'for (i = 0; i <= 1000; ++i) { i }\n' | bc)

# Run each number through the script.
for i in $nums; do

	# Run the GNU bc on the test.
	printf '%s\n' "$i" | bc -q "$timeconst" > "$out1"

	err="$?"

	# If the other bc failed, it's not GNU bc, or this bc.
	if [ "$err" -ne 0 ]; then
		printf '\nOther bc is not GNU compatible. Skipping...\n'
		exit 0
	fi

	# Run the built bc on the test.
	printf '%s\n' "$i" | "$bc" "$@" -q "$timeconst" > "$out2"

	diff "$out1" "$out2"

	error="$?"

	# If fail, bail.
	if [ "$error" -ne 0 ]; then
		printf '\nFailed on input: %s\n' "$i"
		exit "$error"
	fi

done

rm -f "$out1"
rm -f "$out2"

exec printf 'pass\n'
