custom-shell-scripts/detect_overflow at main · jmortiger/custom-shell-scripts · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
#!/usr/bin/env bash

if [ "$1" = '--help' ]; then
	exit 1
elif [ "$1" = '--version' ]; then
	exit 1
fi
show_help() {
	cat << __EOF__
Detect integer overflow in math operations.

Usage:	$0 LHS OPERATOR RHS
	or:	$0 --help
	or:	$0 --version

Options:

__EOF__
}
show_version() {
	cat << __EOF__
$0 1.0.0

Copyright (C) 2025 Justin Morris
__EOF__
}

declare -i lhs=0
declare -i rhs=0
declare operator=''
shopt -s 'extglob'
allowContinue='true'
declare -n opt1=lhs opt2=operator opt3=rhs
while eval "$allowContinue" && (( $# > 0 )); do
	case "$1" in
		(-h | --help)
			show_help
			exit
			;;
		(-v | --version)
			show_version
			exit
			;;
		(*)
			if [[ -n "${opt1+x}" ]]; then
				if [[ -n "${opt2+x}" ]]; then
					if [[ -n "${opt3+x}" ]]; then
						exit 1
					elif [[ "$1" =~ ^-?[[:digit:]]+$ ]]; then
						opt3="$1"
						allowContinue='false'
					else
						exit 1
					fi
				else
					opt2="$1"
				fi
			elif [[ "$1" =~ ^-?[[:digit:]]+$ ]]; then
				opt1="$1"
			else
				exit 1
			fi
			shift
			# allowContinue='false'
			;;
	esac
done

same_sign() {
	local -i root=0
	for param in "$@"; do
		if (( param != 0 )); then
			if ((param < 0 && root > 0)) || ((param > 0 && root < 0)); then
				false
				return $?
			fi
			((root=param))
		fi
	done
	true
	return $?
}
is_positive() {
	for param in "$@"; do
		if ((param < 0)); then
			false
			return $?
		fi
	done
	true
	return $?
}
is_negative() {
	for param in "$@"; do
		if ((param > 0)); then
			false
			return $?
		fi
	done
	true
	return $?
}

declare -r lhs operator rhs

if ((lhs < 0))

if ! eval is_negative "$numerator" "$l_intermediate" && ! eval is_positive "$numerator" "$l_intermediate"; then
	exit_error "OVERFLOW ($whole $l_intermediate)"
fi
((l_intermediate /= denominator));
# if eval is_negative "$numerator" "$denominator" "$l_intermediate"; then
#	exit_error "OVERFLOW ($whole $l_intermediate)"
# elif ! eval is_positive "$numerator" "$denominator" "$l_intermediate"; then
# 	if ! eval is_positive "$numerator" "$denominator" || ! eval is_negative "$numerator" "$denominator"; then
#	exit_error "OVERFLOW ($whole $l_intermediate)"
# 	fi
# fi