1// Copyright 2015 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package big
6
7import (
8	"fmt"
9	"testing"
10)
11
12func TestDecimalString(t *testing.T) {
13	for _, test := range []struct {
14		x    decimal
15		want string
16	}{
17		{want: "0"},
18		{decimal{nil, 1000}, "0"}, // exponent of 0 is ignored
19		{decimal{[]byte("12345"), 0}, "0.12345"},
20		{decimal{[]byte("12345"), -3}, "0.00012345"},
21		{decimal{[]byte("12345"), +3}, "123.45"},
22		{decimal{[]byte("12345"), +10}, "1234500000"},
23	} {
24		if got := test.x.String(); got != test.want {
25			t.Errorf("%v == %s; want %s", test.x, got, test.want)
26		}
27	}
28}
29
30func TestDecimalInit(t *testing.T) {
31	for _, test := range []struct {
32		x     Word
33		shift int
34		want  string
35	}{
36		{0, 0, "0"},
37		{0, -100, "0"},
38		{0, 100, "0"},
39		{1, 0, "1"},
40		{1, 10, "1024"},
41		{1, 100, "1267650600228229401496703205376"},
42		{1, -100, "0.0000000000000000000000000000007888609052210118054117285652827862296732064351090230047702789306640625"},
43		{12345678, 8, "3160493568"},
44		{12345678, -8, "48225.3046875"},
45		{195312, 9, "99999744"},
46		{1953125, 9, "1000000000"},
47	} {
48		var d decimal
49		d.init(nat{test.x}.norm(), test.shift)
50		if got := d.String(); got != test.want {
51			t.Errorf("%d << %d == %s; want %s", test.x, test.shift, got, test.want)
52		}
53	}
54}
55
56func TestDecimalRounding(t *testing.T) {
57	for _, test := range []struct {
58		x              uint64
59		n              int
60		down, even, up string
61	}{
62		{0, 0, "0", "0", "0"},
63		{0, 1, "0", "0", "0"},
64
65		{1, 0, "0", "0", "10"},
66		{5, 0, "0", "0", "10"},
67		{9, 0, "0", "10", "10"},
68
69		{15, 1, "10", "20", "20"},
70		{45, 1, "40", "40", "50"},
71		{95, 1, "90", "100", "100"},
72
73		{12344999, 4, "12340000", "12340000", "12350000"},
74		{12345000, 4, "12340000", "12340000", "12350000"},
75		{12345001, 4, "12340000", "12350000", "12350000"},
76		{23454999, 4, "23450000", "23450000", "23460000"},
77		{23455000, 4, "23450000", "23460000", "23460000"},
78		{23455001, 4, "23450000", "23460000", "23460000"},
79
80		{99994999, 4, "99990000", "99990000", "100000000"},
81		{99995000, 4, "99990000", "100000000", "100000000"},
82		{99999999, 4, "99990000", "100000000", "100000000"},
83
84		{12994999, 4, "12990000", "12990000", "13000000"},
85		{12995000, 4, "12990000", "13000000", "13000000"},
86		{12999999, 4, "12990000", "13000000", "13000000"},
87	} {
88		x := nat(nil).setUint64(test.x)
89
90		var d decimal
91		d.init(x, 0)
92		d.roundDown(test.n)
93		if got := d.String(); got != test.down {
94			t.Errorf("roundDown(%d, %d) = %s; want %s", test.x, test.n, got, test.down)
95		}
96
97		d.init(x, 0)
98		d.round(test.n)
99		if got := d.String(); got != test.even {
100			t.Errorf("round(%d, %d) = %s; want %s", test.x, test.n, got, test.even)
101		}
102
103		d.init(x, 0)
104		d.roundUp(test.n)
105		if got := d.String(); got != test.up {
106			t.Errorf("roundUp(%d, %d) = %s; want %s", test.x, test.n, got, test.up)
107		}
108	}
109}
110
111var sink string
112
113func BenchmarkDecimalConversion(b *testing.B) {
114	for i := 0; i < b.N; i++ {
115		for shift := -100; shift <= +100; shift++ {
116			var d decimal
117			d.init(natOne, shift)
118			sink = d.String()
119		}
120	}
121}
122
123func BenchmarkFloatString(b *testing.B) {
124	x := new(Float)
125	for _, prec := range []uint{1e2, 1e3, 1e4, 1e5} {
126		x.SetPrec(prec).SetRat(NewRat(1, 3))
127		b.Run(fmt.Sprintf("%v", prec), func(b *testing.B) {
128			b.ReportAllocs()
129			for i := 0; i < b.N; i++ {
130				sink = x.String()
131			}
132		})
133	}
134}
135