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	"sync"
14	"testing"
15	"time"
16)
17
18type atofTest struct {
19	in  string
20	out string
21	err error
22}
23
24var atoftests = []atofTest{
25	{"", "0", ErrSyntax},
26	{"1", "1", nil},
27	{"+1", "1", nil},
28	{"1x", "0", ErrSyntax},
29	{"1.1.", "0", ErrSyntax},
30	{"1e23", "1e+23", nil},
31	{"1E23", "1e+23", nil},
32	{"100000000000000000000000", "1e+23", nil},
33	{"1e-100", "1e-100", nil},
34	{"123456700", "1.234567e+08", nil},
35	{"99999999999999974834176", "9.999999999999997e+22", nil},
36	{"100000000000000000000001", "1.0000000000000001e+23", nil},
37	{"100000000000000008388608", "1.0000000000000001e+23", nil},
38	{"100000000000000016777215", "1.0000000000000001e+23", nil},
39	{"100000000000000016777216", "1.0000000000000003e+23", nil},
40	{"-1", "-1", nil},
41	{"-0.1", "-0.1", nil},
42	{"-0", "-0", nil},
43	{"1e-20", "1e-20", nil},
44	{"625e-3", "0.625", nil},
45
46	// zeros
47	{"0", "0", nil},
48	{"0e0", "0", nil},
49	{"-0e0", "-0", nil},
50	{"+0e0", "0", nil},
51	{"0e-0", "0", nil},
52	{"-0e-0", "-0", nil},
53	{"+0e-0", "0", nil},
54	{"0e+0", "0", nil},
55	{"-0e+0", "-0", nil},
56	{"+0e+0", "0", nil},
57	{"0e+01234567890123456789", "0", nil},
58	{"0.00e-01234567890123456789", "0", nil},
59	{"-0e+01234567890123456789", "-0", nil},
60	{"-0.00e-01234567890123456789", "-0", nil},
61	{"0e291", "0", nil}, // issue 15364
62	{"0e292", "0", nil}, // issue 15364
63	{"0e347", "0", nil}, // issue 15364
64	{"0e348", "0", nil}, // issue 15364
65	{"-0e291", "-0", nil},
66	{"-0e292", "-0", nil},
67	{"-0e347", "-0", nil},
68	{"-0e348", "-0", nil},
69
70	// NaNs
71	{"nan", "NaN", nil},
72	{"NaN", "NaN", nil},
73	{"NAN", "NaN", nil},
74
75	// Infs
76	{"inf", "+Inf", nil},
77	{"-Inf", "-Inf", nil},
78	{"+INF", "+Inf", nil},
79	{"-Infinity", "-Inf", nil},
80	{"+INFINITY", "+Inf", nil},
81	{"Infinity", "+Inf", nil},
82
83	// largest float64
84	{"1.7976931348623157e308", "1.7976931348623157e+308", nil},
85	{"-1.7976931348623157e308", "-1.7976931348623157e+308", nil},
86	// next float64 - too large
87	{"1.7976931348623159e308", "+Inf", ErrRange},
88	{"-1.7976931348623159e308", "-Inf", ErrRange},
89	// the border is ...158079
90	// borderline - okay
91	{"1.7976931348623158e308", "1.7976931348623157e+308", nil},
92	{"-1.7976931348623158e308", "-1.7976931348623157e+308", nil},
93	// borderline - too large
94	{"1.797693134862315808e308", "+Inf", ErrRange},
95	{"-1.797693134862315808e308", "-Inf", ErrRange},
96
97	// a little too large
98	{"1e308", "1e+308", nil},
99	{"2e308", "+Inf", ErrRange},
100	{"1e309", "+Inf", ErrRange},
101
102	// way too large
103	{"1e310", "+Inf", ErrRange},
104	{"-1e310", "-Inf", ErrRange},
105	{"1e400", "+Inf", ErrRange},
106	{"-1e400", "-Inf", ErrRange},
107	{"1e400000", "+Inf", ErrRange},
108	{"-1e400000", "-Inf", ErrRange},
109
110	// denormalized
111	{"1e-305", "1e-305", nil},
112	{"1e-306", "1e-306", nil},
113	{"1e-307", "1e-307", nil},
114	{"1e-308", "1e-308", nil},
115	{"1e-309", "1e-309", nil},
116	{"1e-310", "1e-310", nil},
117	{"1e-322", "1e-322", nil},
118	// smallest denormal
119	{"5e-324", "5e-324", nil},
120	{"4e-324", "5e-324", nil},
121	{"3e-324", "5e-324", nil},
122	// too small
123	{"2e-324", "0", nil},
124	// way too small
125	{"1e-350", "0", nil},
126	{"1e-400000", "0", nil},
127
128	// try to overflow exponent
129	{"1e-4294967296", "0", nil},
130	{"1e+4294967296", "+Inf", ErrRange},
131	{"1e-18446744073709551616", "0", nil},
132	{"1e+18446744073709551616", "+Inf", ErrRange},
133
134	// Parse errors
135	{"1e", "0", ErrSyntax},
136	{"1e-", "0", ErrSyntax},
137	{".e-1", "0", ErrSyntax},
138	{"1\x00.2", "0", ErrSyntax},
139
140	// http://www.exploringbinary.com/java-hangs-when-converting-2-2250738585072012e-308/
141	{"2.2250738585072012e-308", "2.2250738585072014e-308", nil},
142	// http://www.exploringbinary.com/php-hangs-on-numeric-value-2-2250738585072011e-308/
143	{"2.2250738585072011e-308", "2.225073858507201e-308", nil},
144
145	// A very large number (initially wrongly parsed by the fast algorithm).
146	{"4.630813248087435e+307", "4.630813248087435e+307", nil},
147
148	// A different kind of very large number.
149	{"22.222222222222222", "22.22222222222222", nil},
150	{"2." + strings.Repeat("2", 4000) + "e+1", "22.22222222222222", nil},
151
152	// Exactly halfway between 1 and math.Nextafter(1, 2).
153	// Round to even (down).
154	{"1.00000000000000011102230246251565404236316680908203125", "1", nil},
155	// Slightly lower; still round down.
156	{"1.00000000000000011102230246251565404236316680908203124", "1", nil},
157	// Slightly higher; round up.
158	{"1.00000000000000011102230246251565404236316680908203126", "1.0000000000000002", nil},
159	// Slightly higher, but you have to read all the way to the end.
160	{"1.00000000000000011102230246251565404236316680908203125" + strings.Repeat("0", 10000) + "1", "1.0000000000000002", nil},
161}
162
163var atof32tests = []atofTest{
164	// Exactly halfway between 1 and the next float32.
165	// Round to even (down).
166	{"1.000000059604644775390625", "1", nil},
167	// Slightly lower.
168	{"1.000000059604644775390624", "1", nil},
169	// Slightly higher.
170	{"1.000000059604644775390626", "1.0000001", nil},
171	// Slightly higher, but you have to read all the way to the end.
172	{"1.000000059604644775390625" + strings.Repeat("0", 10000) + "1", "1.0000001", nil},
173
174	// largest float32: (1<<128) * (1 - 2^-24)
175	{"340282346638528859811704183484516925440", "3.4028235e+38", nil},
176	{"-340282346638528859811704183484516925440", "-3.4028235e+38", nil},
177	// next float32 - too large
178	{"3.4028236e38", "+Inf", ErrRange},
179	{"-3.4028236e38", "-Inf", ErrRange},
180	// the border is 3.40282356779...e+38
181	// borderline - okay
182	{"3.402823567e38", "3.4028235e+38", nil},
183	{"-3.402823567e38", "-3.4028235e+38", nil},
184	// borderline - too large
185	{"3.4028235678e38", "+Inf", ErrRange},
186	{"-3.4028235678e38", "-Inf", ErrRange},
187
188	// Denormals: less than 2^-126
189	{"1e-38", "1e-38", nil},
190	{"1e-39", "1e-39", nil},
191	{"1e-40", "1e-40", nil},
192	{"1e-41", "1e-41", nil},
193	{"1e-42", "1e-42", nil},
194	{"1e-43", "1e-43", nil},
195	{"1e-44", "1e-44", nil},
196	{"6e-45", "6e-45", nil}, // 4p-149 = 5.6e-45
197	{"5e-45", "6e-45", nil},
198	// Smallest denormal
199	{"1e-45", "1e-45", nil}, // 1p-149 = 1.4e-45
200	{"2e-45", "1e-45", nil},
201
202	// 2^92 = 8388608p+69 = 4951760157141521099596496896 (4.9517602e27)
203	// is an exact power of two that needs 8 decimal digits to be correctly
204	// parsed back.
205	// The float32 before is 16777215p+68 = 4.95175986e+27
206	// The halfway is 4.951760009. A bad algorithm that thinks the previous
207	// float32 is 8388607p+69 will shorten incorrectly to 4.95176e+27.
208	{"4951760157141521099596496896", "4.9517602e+27", nil},
209}
210
211type atofSimpleTest struct {
212	x float64
213	s string
214}
215
216var (
217	atofOnce               sync.Once
218	atofRandomTests        []atofSimpleTest
219	benchmarksRandomBits   [1024]string
220	benchmarksRandomNormal [1024]string
221)
222
223func initAtof() {
224	atofOnce.Do(initAtofOnce)
225}
226
227func initAtofOnce() {
228	// The atof routines return NumErrors wrapping
229	// the error and the string. Convert the table above.
230	for i := range atoftests {
231		test := &atoftests[i]
232		if test.err != nil {
233			test.err = &NumError{"ParseFloat", test.in, test.err}
234		}
235	}
236	for i := range atof32tests {
237		test := &atof32tests[i]
238		if test.err != nil {
239			test.err = &NumError{"ParseFloat", test.in, test.err}
240		}
241	}
242
243	// Generate random inputs for tests and benchmarks
244	rand.Seed(time.Now().UnixNano())
245	if testing.Short() {
246		atofRandomTests = make([]atofSimpleTest, 100)
247	} else {
248		atofRandomTests = make([]atofSimpleTest, 10000)
249	}
250	for i := range atofRandomTests {
251		n := uint64(rand.Uint32())<<32 | uint64(rand.Uint32())
252		x := math.Float64frombits(n)
253		s := FormatFloat(x, 'g', -1, 64)
254		atofRandomTests[i] = atofSimpleTest{x, s}
255	}
256
257	for i := range benchmarksRandomBits {
258		bits := uint64(rand.Uint32())<<32 | uint64(rand.Uint32())
259		x := math.Float64frombits(bits)
260		benchmarksRandomBits[i] = FormatFloat(x, 'g', -1, 64)
261	}
262
263	for i := range benchmarksRandomNormal {
264		x := rand.NormFloat64()
265		benchmarksRandomNormal[i] = FormatFloat(x, 'g', -1, 64)
266	}
267}
268
269func testAtof(t *testing.T, opt bool) {
270	initAtof()
271	oldopt := SetOptimize(opt)
272	for i := 0; i < len(atoftests); i++ {
273		test := &atoftests[i]
274		out, err := ParseFloat(test.in, 64)
275		outs := FormatFloat(out, 'g', -1, 64)
276		if outs != test.out || !reflect.DeepEqual(err, test.err) {
277			t.Errorf("ParseFloat(%v, 64) = %v, %v want %v, %v",
278				test.in, out, err, test.out, test.err)
279		}
280
281		if float64(float32(out)) == out {
282			out, err := ParseFloat(test.in, 32)
283			out32 := float32(out)
284			if float64(out32) != out {
285				t.Errorf("ParseFloat(%v, 32) = %v, not a float32 (closest is %v)", test.in, out, float64(out32))
286				continue
287			}
288			outs := FormatFloat(float64(out32), 'g', -1, 32)
289			if outs != test.out || !reflect.DeepEqual(err, test.err) {
290				t.Errorf("ParseFloat(%v, 32) = %v, %v want %v, %v  # %v",
291					test.in, out32, err, test.out, test.err, out)
292			}
293		}
294	}
295	for _, test := range atof32tests {
296		out, err := ParseFloat(test.in, 32)
297		out32 := float32(out)
298		if float64(out32) != out {
299			t.Errorf("ParseFloat(%v, 32) = %v, not a float32 (closest is %v)", test.in, out, float64(out32))
300			continue
301		}
302		outs := FormatFloat(float64(out32), 'g', -1, 32)
303		if outs != test.out || !reflect.DeepEqual(err, test.err) {
304			t.Errorf("ParseFloat(%v, 32) = %v, %v want %v, %v  # %v",
305				test.in, out32, err, test.out, test.err, out)
306		}
307	}
308	SetOptimize(oldopt)
309}
310
311func TestAtof(t *testing.T) { testAtof(t, true) }
312
313func TestAtofSlow(t *testing.T) { testAtof(t, false) }
314
315func TestAtofRandom(t *testing.T) {
316	initAtof()
317	for _, test := range atofRandomTests {
318		x, _ := ParseFloat(test.s, 64)
319		switch {
320		default:
321			t.Errorf("number %s badly parsed as %b (expected %b)", test.s, x, test.x)
322		case x == test.x:
323		case math.IsNaN(test.x) && math.IsNaN(x):
324		}
325	}
326	t.Logf("tested %d random numbers", len(atofRandomTests))
327}
328
329var roundTripCases = []struct {
330	f float64
331	s string
332}{
333	// Issue 2917.
334	// This test will break the optimized conversion if the
335	// FPU is using 80-bit registers instead of 64-bit registers,
336	// usually because the operating system initialized the
337	// thread with 80-bit precision and the Go runtime didn't
338	// fix the FP control word.
339	{8865794286000691 << 39, "4.87402195346389e+27"},
340	{8865794286000692 << 39, "4.8740219534638903e+27"},
341}
342
343func TestRoundTrip(t *testing.T) {
344	for _, tt := range roundTripCases {
345		old := SetOptimize(false)
346		s := FormatFloat(tt.f, 'g', -1, 64)
347		if s != tt.s {
348			t.Errorf("no-opt FormatFloat(%b) = %s, want %s", tt.f, s, tt.s)
349		}
350		f, err := ParseFloat(tt.s, 64)
351		if f != tt.f || err != nil {
352			t.Errorf("no-opt ParseFloat(%s) = %b, %v want %b, nil", tt.s, f, err, tt.f)
353		}
354		SetOptimize(true)
355		s = FormatFloat(tt.f, 'g', -1, 64)
356		if s != tt.s {
357			t.Errorf("opt FormatFloat(%b) = %s, want %s", tt.f, s, tt.s)
358		}
359		f, err = ParseFloat(tt.s, 64)
360		if f != tt.f || err != nil {
361			t.Errorf("opt ParseFloat(%s) = %b, %v want %b, nil", tt.s, f, err, tt.f)
362		}
363		SetOptimize(old)
364	}
365}
366
367// TestRoundTrip32 tries a fraction of all finite positive float32 values.
368func TestRoundTrip32(t *testing.T) {
369	step := uint32(997)
370	if testing.Short() {
371		step = 99991
372	}
373	count := 0
374	for i := uint32(0); i < 0xff<<23; i += step {
375		f := math.Float32frombits(i)
376		if i&1 == 1 {
377			f = -f // negative
378		}
379		s := FormatFloat(float64(f), 'g', -1, 32)
380
381		parsed, err := ParseFloat(s, 32)
382		parsed32 := float32(parsed)
383		switch {
384		case err != nil:
385			t.Errorf("ParseFloat(%q, 32) gave error %s", s, err)
386		case float64(parsed32) != parsed:
387			t.Errorf("ParseFloat(%q, 32) = %v, not a float32 (nearest is %v)", s, parsed, parsed32)
388		case parsed32 != f:
389			t.Errorf("ParseFloat(%q, 32) = %b (expected %b)", s, parsed32, f)
390		}
391		count++
392	}
393	t.Logf("tested %d float32's", count)
394}
395
396func BenchmarkAtof64Decimal(b *testing.B) {
397	for i := 0; i < b.N; i++ {
398		ParseFloat("33909", 64)
399	}
400}
401
402func BenchmarkAtof64Float(b *testing.B) {
403	for i := 0; i < b.N; i++ {
404		ParseFloat("339.7784", 64)
405	}
406}
407
408func BenchmarkAtof64FloatExp(b *testing.B) {
409	for i := 0; i < b.N; i++ {
410		ParseFloat("-5.09e75", 64)
411	}
412}
413
414func BenchmarkAtof64Big(b *testing.B) {
415	for i := 0; i < b.N; i++ {
416		ParseFloat("123456789123456789123456789", 64)
417	}
418}
419
420func BenchmarkAtof64RandomBits(b *testing.B) {
421	for i := 0; i < b.N; i++ {
422		ParseFloat(benchmarksRandomBits[i%1024], 64)
423	}
424}
425
426func BenchmarkAtof64RandomFloats(b *testing.B) {
427	for i := 0; i < b.N; i++ {
428		ParseFloat(benchmarksRandomNormal[i%1024], 64)
429	}
430}
431
432func BenchmarkAtof32Decimal(b *testing.B) {
433	for i := 0; i < b.N; i++ {
434		ParseFloat("33909", 32)
435	}
436}
437
438func BenchmarkAtof32Float(b *testing.B) {
439	for i := 0; i < b.N; i++ {
440		ParseFloat("339.778", 32)
441	}
442}
443
444func BenchmarkAtof32FloatExp(b *testing.B) {
445	for i := 0; i < b.N; i++ {
446		ParseFloat("12.3456e32", 32)
447	}
448}
449
450var float32strings [4096]string
451
452func BenchmarkAtof32Random(b *testing.B) {
453	n := uint32(997)
454	for i := range float32strings {
455		n = (99991*n + 42) % (0xff << 23)
456		float32strings[i] = FormatFloat(float64(math.Float32frombits(n)), 'g', -1, 32)
457	}
458	b.ResetTimer()
459	for i := 0; i < b.N; i++ {
460		ParseFloat(float32strings[i%4096], 32)
461	}
462}
463