1// Copyright 2009 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 strconv_test
6
7import (
8	"math"
9	"math/rand"
10	"reflect"
11	. "strconv"
12	"strings"
13	"testing"
14	"time"
15)
16
17type atofTest struct {
18	in  string
19	out string
20	err error
21}
22
23var atoftests = []atofTest{
24	{"", "0", ErrSyntax},
25	{"1", "1", nil},
26	{"+1", "1", nil},
27	{"1x", "0", ErrSyntax},
28	{"1.1.", "0", ErrSyntax},
29	{"1e23", "1e+23", nil},
30	{"1E23", "1e+23", nil},
31	{"100000000000000000000000", "1e+23", nil},
32	{"1e-100", "1e-100", nil},
33	{"123456700", "1.234567e+08", nil},
34	{"99999999999999974834176", "9.999999999999997e+22", nil},
35	{"100000000000000000000001", "1.0000000000000001e+23", nil},
36	{"100000000000000008388608", "1.0000000000000001e+23", nil},
37	{"100000000000000016777215", "1.0000000000000001e+23", nil},
38	{"100000000000000016777216", "1.0000000000000003e+23", nil},
39	{"-1", "-1", nil},
40	{"-0.1", "-0.1", nil},
41	{"-0", "-0", nil},
42	{"1e-20", "1e-20", nil},
43	{"625e-3", "0.625", nil},
44
45	// NaNs
46	{"nan", "NaN", nil},
47	{"NaN", "NaN", nil},
48	{"NAN", "NaN", nil},
49
50	// Infs
51	{"inf", "+Inf", nil},
52	{"-Inf", "-Inf", nil},
53	{"+INF", "+Inf", nil},
54	{"-Infinity", "-Inf", nil},
55	{"+INFINITY", "+Inf", nil},
56	{"Infinity", "+Inf", nil},
57
58	// largest float64
59	{"1.7976931348623157e308", "1.7976931348623157e+308", nil},
60	{"-1.7976931348623157e308", "-1.7976931348623157e+308", nil},
61	// next float64 - too large
62	{"1.7976931348623159e308", "+Inf", ErrRange},
63	{"-1.7976931348623159e308", "-Inf", ErrRange},
64	// the border is ...158079
65	// borderline - okay
66	{"1.7976931348623158e308", "1.7976931348623157e+308", nil},
67	{"-1.7976931348623158e308", "-1.7976931348623157e+308", nil},
68	// borderline - too large
69	{"1.797693134862315808e308", "+Inf", ErrRange},
70	{"-1.797693134862315808e308", "-Inf", ErrRange},
71
72	// a little too large
73	{"1e308", "1e+308", nil},
74	{"2e308", "+Inf", ErrRange},
75	{"1e309", "+Inf", ErrRange},
76
77	// way too large
78	{"1e310", "+Inf", ErrRange},
79	{"-1e310", "-Inf", ErrRange},
80	{"1e400", "+Inf", ErrRange},
81	{"-1e400", "-Inf", ErrRange},
82	{"1e400000", "+Inf", ErrRange},
83	{"-1e400000", "-Inf", ErrRange},
84
85	// denormalized
86	{"1e-305", "1e-305", nil},
87	{"1e-306", "1e-306", nil},
88	{"1e-307", "1e-307", nil},
89	{"1e-308", "1e-308", nil},
90	{"1e-309", "1e-309", nil},
91	{"1e-310", "1e-310", nil},
92	{"1e-322", "1e-322", nil},
93	// smallest denormal
94	{"5e-324", "5e-324", nil},
95	{"4e-324", "5e-324", nil},
96	{"3e-324", "5e-324", nil},
97	// too small
98	{"2e-324", "0", nil},
99	// way too small
100	{"1e-350", "0", nil},
101	{"1e-400000", "0", nil},
102
103	// try to overflow exponent
104	{"1e-4294967296", "0", nil},
105	{"1e+4294967296", "+Inf", ErrRange},
106	{"1e-18446744073709551616", "0", nil},
107	{"1e+18446744073709551616", "+Inf", ErrRange},
108
109	// Parse errors
110	{"1e", "0", ErrSyntax},
111	{"1e-", "0", ErrSyntax},
112	{".e-1", "0", ErrSyntax},
113	{"1\x00.2", "0", ErrSyntax},
114
115	// http://www.exploringbinary.com/java-hangs-when-converting-2-2250738585072012e-308/
116	{"2.2250738585072012e-308", "2.2250738585072014e-308", nil},
117	// http://www.exploringbinary.com/php-hangs-on-numeric-value-2-2250738585072011e-308/
118	{"2.2250738585072011e-308", "2.225073858507201e-308", nil},
119
120	// A very large number (initially wrongly parsed by the fast algorithm).
121	{"4.630813248087435e+307", "4.630813248087435e+307", nil},
122
123	// A different kind of very large number.
124	{"22.222222222222222", "22.22222222222222", nil},
125	{"2." + strings.Repeat("2", 4000) + "e+1", "22.22222222222222", nil},
126
127	// Exactly halfway between 1 and math.Nextafter(1, 2).
128	// Round to even (down).
129	{"1.00000000000000011102230246251565404236316680908203125", "1", nil},
130	// Slightly lower; still round down.
131	{"1.00000000000000011102230246251565404236316680908203124", "1", nil},
132	// Slightly higher; round up.
133	{"1.00000000000000011102230246251565404236316680908203126", "1.0000000000000002", nil},
134	// Slightly higher, but you have to read all the way to the end.
135	{"1.00000000000000011102230246251565404236316680908203125" + strings.Repeat("0", 10000) + "1", "1.0000000000000002", nil},
136}
137
138var atof32tests = []atofTest{
139	// Exactly halfway between 1 and the next float32.
140	// Round to even (down).
141	{"1.000000059604644775390625", "1", nil},
142	// Slightly lower.
143	{"1.000000059604644775390624", "1", nil},
144	// Slightly higher.
145	{"1.000000059604644775390626", "1.0000001", nil},
146	// Slightly higher, but you have to read all the way to the end.
147	{"1.000000059604644775390625" + strings.Repeat("0", 10000) + "1", "1.0000001", nil},
148
149	// largest float32: (1<<128) * (1 - 2^-24)
150	{"340282346638528859811704183484516925440", "3.4028235e+38", nil},
151	{"-340282346638528859811704183484516925440", "-3.4028235e+38", nil},
152	// next float32 - too large
153	{"3.4028236e38", "+Inf", ErrRange},
154	{"-3.4028236e38", "-Inf", ErrRange},
155	// the border is 3.40282356779...e+38
156	// borderline - okay
157	{"3.402823567e38", "3.4028235e+38", nil},
158	{"-3.402823567e38", "-3.4028235e+38", nil},
159	// borderline - too large
160	{"3.4028235678e38", "+Inf", ErrRange},
161	{"-3.4028235678e38", "-Inf", ErrRange},
162
163	// Denormals: less than 2^-126
164	{"1e-38", "1e-38", nil},
165	{"1e-39", "1e-39", nil},
166	{"1e-40", "1e-40", nil},
167	{"1e-41", "1e-41", nil},
168	{"1e-42", "1e-42", nil},
169	{"1e-43", "1e-43", nil},
170	{"1e-44", "1e-44", nil},
171	{"6e-45", "6e-45", nil}, // 4p-149 = 5.6e-45
172	{"5e-45", "6e-45", nil},
173	// Smallest denormal
174	{"1e-45", "1e-45", nil}, // 1p-149 = 1.4e-45
175	{"2e-45", "1e-45", nil},
176
177	// 2^92 = 8388608p+69 = 4951760157141521099596496896 (4.9517602e27)
178	// is an exact power of two that needs 8 decimal digits to be correctly
179	// parsed back.
180	// The float32 before is 16777215p+68 = 4.95175986e+27
181	// The halfway is 4.951760009. A bad algorithm that thinks the previous
182	// float32 is 8388607p+69 will shorten incorrectly to 4.95176e+27.
183	{"4951760157141521099596496896", "4.9517602e+27", nil},
184}
185
186type atofSimpleTest struct {
187	x float64
188	s string
189}
190
191var (
192	atofRandomTests        []atofSimpleTest
193	benchmarksRandomBits   [1024]string
194	benchmarksRandomNormal [1024]string
195)
196
197func init() {
198	// The atof routines return NumErrors wrapping
199	// the error and the string.  Convert the table above.
200	for i := range atoftests {
201		test := &atoftests[i]
202		if test.err != nil {
203			test.err = &NumError{"ParseFloat", test.in, test.err}
204		}
205	}
206	for i := range atof32tests {
207		test := &atof32tests[i]
208		if test.err != nil {
209			test.err = &NumError{"ParseFloat", test.in, test.err}
210		}
211	}
212
213	// Generate random inputs for tests and benchmarks
214	rand.Seed(time.Now().UnixNano())
215	if testing.Short() {
216		atofRandomTests = make([]atofSimpleTest, 100)
217	} else {
218		atofRandomTests = make([]atofSimpleTest, 10000)
219	}
220	for i := range atofRandomTests {
221		n := uint64(rand.Uint32())<<32 | uint64(rand.Uint32())
222		x := math.Float64frombits(n)
223		s := FormatFloat(x, 'g', -1, 64)
224		atofRandomTests[i] = atofSimpleTest{x, s}
225	}
226
227	for i := range benchmarksRandomBits {
228		bits := uint64(rand.Uint32())<<32 | uint64(rand.Uint32())
229		x := math.Float64frombits(bits)
230		benchmarksRandomBits[i] = FormatFloat(x, 'g', -1, 64)
231	}
232
233	for i := range benchmarksRandomNormal {
234		x := rand.NormFloat64()
235		benchmarksRandomNormal[i] = FormatFloat(x, 'g', -1, 64)
236	}
237}
238
239func testAtof(t *testing.T, opt bool) {
240	oldopt := SetOptimize(opt)
241	for i := 0; i < len(atoftests); i++ {
242		test := &atoftests[i]
243		out, err := ParseFloat(test.in, 64)
244		outs := FormatFloat(out, 'g', -1, 64)
245		if outs != test.out || !reflect.DeepEqual(err, test.err) {
246			t.Errorf("ParseFloat(%v, 64) = %v, %v want %v, %v",
247				test.in, out, err, test.out, test.err)
248		}
249
250		if float64(float32(out)) == out {
251			out, err := ParseFloat(test.in, 32)
252			out32 := float32(out)
253			if float64(out32) != out {
254				t.Errorf("ParseFloat(%v, 32) = %v, not a float32 (closest is %v)", test.in, out, float64(out32))
255				continue
256			}
257			outs := FormatFloat(float64(out32), 'g', -1, 32)
258			if outs != test.out || !reflect.DeepEqual(err, test.err) {
259				t.Errorf("ParseFloat(%v, 32) = %v, %v want %v, %v  # %v",
260					test.in, out32, err, test.out, test.err, out)
261			}
262		}
263	}
264	for _, test := range atof32tests {
265		out, err := ParseFloat(test.in, 32)
266		out32 := float32(out)
267		if float64(out32) != out {
268			t.Errorf("ParseFloat(%v, 32) = %v, not a float32 (closest is %v)", test.in, out, float64(out32))
269			continue
270		}
271		outs := FormatFloat(float64(out32), 'g', -1, 32)
272		if outs != test.out || !reflect.DeepEqual(err, test.err) {
273			t.Errorf("ParseFloat(%v, 32) = %v, %v want %v, %v  # %v",
274				test.in, out32, err, test.out, test.err, out)
275		}
276	}
277	SetOptimize(oldopt)
278}
279
280func TestAtof(t *testing.T) { testAtof(t, true) }
281
282func TestAtofSlow(t *testing.T) { testAtof(t, false) }
283
284func TestAtofRandom(t *testing.T) {
285	for _, test := range atofRandomTests {
286		x, _ := ParseFloat(test.s, 64)
287		switch {
288		default:
289			t.Errorf("number %s badly parsed as %b (expected %b)", test.s, x, test.x)
290		case x == test.x:
291		case math.IsNaN(test.x) && math.IsNaN(x):
292		}
293	}
294	t.Logf("tested %d random numbers", len(atofRandomTests))
295}
296
297var roundTripCases = []struct {
298	f float64
299	s string
300}{
301	// Issue 2917.
302	// This test will break the optimized conversion if the
303	// FPU is using 80-bit registers instead of 64-bit registers,
304	// usually because the operating system initialized the
305	// thread with 80-bit precision and the Go runtime didn't
306	// fix the FP control word.
307	{8865794286000691 << 39, "4.87402195346389e+27"},
308	{8865794286000692 << 39, "4.8740219534638903e+27"},
309}
310
311func TestRoundTrip(t *testing.T) {
312	for _, tt := range roundTripCases {
313		old := SetOptimize(false)
314		s := FormatFloat(tt.f, 'g', -1, 64)
315		if s != tt.s {
316			t.Errorf("no-opt FormatFloat(%b) = %s, want %s", tt.f, s, tt.s)
317		}
318		f, err := ParseFloat(tt.s, 64)
319		if f != tt.f || err != nil {
320			t.Errorf("no-opt ParseFloat(%s) = %b, %v want %b, nil", tt.s, f, err, tt.f)
321		}
322		SetOptimize(true)
323		s = FormatFloat(tt.f, 'g', -1, 64)
324		if s != tt.s {
325			t.Errorf("opt FormatFloat(%b) = %s, want %s", tt.f, s, tt.s)
326		}
327		f, err = ParseFloat(tt.s, 64)
328		if f != tt.f || err != nil {
329			t.Errorf("opt ParseFloat(%s) = %b, %v want %b, nil", tt.s, f, err, tt.f)
330		}
331		SetOptimize(old)
332	}
333}
334
335// TestRoundTrip32 tries a fraction of all finite positive float32 values.
336func TestRoundTrip32(t *testing.T) {
337	step := uint32(997)
338	if testing.Short() {
339		step = 99991
340	}
341	count := 0
342	for i := uint32(0); i < 0xff<<23; i += step {
343		f := math.Float32frombits(i)
344		if i&1 == 1 {
345			f = -f // negative
346		}
347		s := FormatFloat(float64(f), 'g', -1, 32)
348
349		parsed, err := ParseFloat(s, 32)
350		parsed32 := float32(parsed)
351		switch {
352		case err != nil:
353			t.Errorf("ParseFloat(%q, 32) gave error %s", s, err)
354		case float64(parsed32) != parsed:
355			t.Errorf("ParseFloat(%q, 32) = %v, not a float32 (nearest is %v)", s, parsed, parsed32)
356		case parsed32 != f:
357			t.Errorf("ParseFloat(%q, 32) = %b (expected %b)", s, parsed32, f)
358		}
359		count++
360	}
361	t.Logf("tested %d float32's", count)
362}
363
364func BenchmarkAtof64Decimal(b *testing.B) {
365	for i := 0; i < b.N; i++ {
366		ParseFloat("33909", 64)
367	}
368}
369
370func BenchmarkAtof64Float(b *testing.B) {
371	for i := 0; i < b.N; i++ {
372		ParseFloat("339.7784", 64)
373	}
374}
375
376func BenchmarkAtof64FloatExp(b *testing.B) {
377	for i := 0; i < b.N; i++ {
378		ParseFloat("-5.09e75", 64)
379	}
380}
381
382func BenchmarkAtof64Big(b *testing.B) {
383	for i := 0; i < b.N; i++ {
384		ParseFloat("123456789123456789123456789", 64)
385	}
386}
387
388func BenchmarkAtof64RandomBits(b *testing.B) {
389	for i := 0; i < b.N; i++ {
390		ParseFloat(benchmarksRandomBits[i%1024], 64)
391	}
392}
393
394func BenchmarkAtof64RandomFloats(b *testing.B) {
395	for i := 0; i < b.N; i++ {
396		ParseFloat(benchmarksRandomNormal[i%1024], 64)
397	}
398}
399
400func BenchmarkAtof32Decimal(b *testing.B) {
401	for i := 0; i < b.N; i++ {
402		ParseFloat("33909", 32)
403	}
404}
405
406func BenchmarkAtof32Float(b *testing.B) {
407	for i := 0; i < b.N; i++ {
408		ParseFloat("339.778", 32)
409	}
410}
411
412func BenchmarkAtof32FloatExp(b *testing.B) {
413	for i := 0; i < b.N; i++ {
414		ParseFloat("12.3456e32", 32)
415	}
416}
417
418var float32strings [4096]string
419
420func BenchmarkAtof32Random(b *testing.B) {
421	n := uint32(997)
422	for i := range float32strings {
423		n = (99991*n + 42) % (0xff << 23)
424		float32strings[i] = FormatFloat(float64(math.Float32frombits(n)), 'g', -1, 32)
425	}
426	b.ResetTimer()
427	for i := 0; i < b.N; i++ {
428		ParseFloat(float32strings[i%4096], 32)
429	}
430}
431