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 5 package strconv_test 6 7 import ( 8 "math" 9 "math/rand" 10 "reflect" 11 . "strconv" 12 "strings" 13 "testing" 14 "time" 15 ) 16 17 type atofTest struct { 18 in string 19 out string 20 err error 21 } 22 23 var 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 // zeros 46 {"0", "0", nil}, 47 {"0e0", "0", nil}, 48 {"-0e0", "-0", nil}, 49 {"+0e0", "0", nil}, 50 {"0e-0", "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+01234567890123456789", "0", nil}, 57 {"0.00e-01234567890123456789", "0", nil}, 58 {"-0e+01234567890123456789", "-0", nil}, 59 {"-0.00e-01234567890123456789", "-0", nil}, 60 {"0e291", "0", nil}, // issue 15364 61 {"0e292", "0", nil}, // issue 15364 62 {"0e347", "0", nil}, // issue 15364 63 {"0e348", "0", nil}, // issue 15364 64 {"-0e291", "-0", nil}, 65 {"-0e292", "-0", nil}, 66 {"-0e347", "-0", nil}, 67 {"-0e348", "-0", nil}, 68 69 // NaNs 70 {"nan", "NaN", nil}, 71 {"NaN", "NaN", nil}, 72 {"NAN", "NaN", nil}, 73 74 // Infs 75 {"inf", "+Inf", nil}, 76 {"-Inf", "-Inf", nil}, 77 {"+INF", "+Inf", nil}, 78 {"-Infinity", "-Inf", nil}, 79 {"+INFINITY", "+Inf", nil}, 80 {"Infinity", "+Inf", nil}, 81 82 // largest float64 83 {"1.7976931348623157e308", "1.7976931348623157e+308", nil}, 84 {"-1.7976931348623157e308", "-1.7976931348623157e+308", nil}, 85 // next float64 - too large 86 {"1.7976931348623159e308", "+Inf", ErrRange}, 87 {"-1.7976931348623159e308", "-Inf", ErrRange}, 88 // the border is ...158079 89 // borderline - okay 90 {"1.7976931348623158e308", "1.7976931348623157e+308", nil}, 91 {"-1.7976931348623158e308", "-1.7976931348623157e+308", nil}, 92 // borderline - too large 93 {"1.797693134862315808e308", "+Inf", ErrRange}, 94 {"-1.797693134862315808e308", "-Inf", ErrRange}, 95 96 // a little too large 97 {"1e308", "1e+308", nil}, 98 {"2e308", "+Inf", ErrRange}, 99 {"1e309", "+Inf", ErrRange}, 100 101 // way too large 102 {"1e310", "+Inf", ErrRange}, 103 {"-1e310", "-Inf", ErrRange}, 104 {"1e400", "+Inf", ErrRange}, 105 {"-1e400", "-Inf", ErrRange}, 106 {"1e400000", "+Inf", ErrRange}, 107 {"-1e400000", "-Inf", ErrRange}, 108 109 // denormalized 110 {"1e-305", "1e-305", nil}, 111 {"1e-306", "1e-306", nil}, 112 {"1e-307", "1e-307", nil}, 113 {"1e-308", "1e-308", nil}, 114 {"1e-309", "1e-309", nil}, 115 {"1e-310", "1e-310", nil}, 116 {"1e-322", "1e-322", nil}, 117 // smallest denormal 118 {"5e-324", "5e-324", nil}, 119 {"4e-324", "5e-324", nil}, 120 {"3e-324", "5e-324", nil}, 121 // too small 122 {"2e-324", "0", nil}, 123 // way too small 124 {"1e-350", "0", nil}, 125 {"1e-400000", "0", nil}, 126 127 // try to overflow exponent 128 {"1e-4294967296", "0", nil}, 129 {"1e+4294967296", "+Inf", ErrRange}, 130 {"1e-18446744073709551616", "0", nil}, 131 {"1e+18446744073709551616", "+Inf", ErrRange}, 132 133 // Parse errors 134 {"1e", "0", ErrSyntax}, 135 {"1e-", "0", ErrSyntax}, 136 {".e-1", "0", ErrSyntax}, 137 {"1\x00.2", "0", ErrSyntax}, 138 139 // http://www.exploringbinary.com/java-hangs-when-converting-2-2250738585072012e-308/ 140 {"2.2250738585072012e-308", "2.2250738585072014e-308", nil}, 141 // http://www.exploringbinary.com/php-hangs-on-numeric-value-2-2250738585072011e-308/ 142 {"2.2250738585072011e-308", "2.225073858507201e-308", nil}, 143 144 // A very large number (initially wrongly parsed by the fast algorithm). 145 {"4.630813248087435e+307", "4.630813248087435e+307", nil}, 146 147 // A different kind of very large number. 148 {"22.222222222222222", "22.22222222222222", nil}, 149 {"2." + strings.Repeat("2", 4000) + "e+1", "22.22222222222222", nil}, 150 151 // Exactly halfway between 1 and math.Nextafter(1, 2). 152 // Round to even (down). 153 {"1.00000000000000011102230246251565404236316680908203125", "1", nil}, 154 // Slightly lower; still round down. 155 {"1.00000000000000011102230246251565404236316680908203124", "1", nil}, 156 // Slightly higher; round up. 157 {"1.00000000000000011102230246251565404236316680908203126", "1.0000000000000002", nil}, 158 // Slightly higher, but you have to read all the way to the end. 159 {"1.00000000000000011102230246251565404236316680908203125" + strings.Repeat("0", 10000) + "1", "1.0000000000000002", nil}, 160 } 161 162 var atof32tests = []atofTest{ 163 // Exactly halfway between 1 and the next float32. 164 // Round to even (down). 165 {"1.000000059604644775390625", "1", nil}, 166 // Slightly lower. 167 {"1.000000059604644775390624", "1", nil}, 168 // Slightly higher. 169 {"1.000000059604644775390626", "1.0000001", nil}, 170 // Slightly higher, but you have to read all the way to the end. 171 {"1.000000059604644775390625" + strings.Repeat("0", 10000) + "1", "1.0000001", nil}, 172 173 // largest float32: (1<<128) * (1 - 2^-24) 174 {"340282346638528859811704183484516925440", "3.4028235e+38", nil}, 175 {"-340282346638528859811704183484516925440", "-3.4028235e+38", nil}, 176 // next float32 - too large 177 {"3.4028236e38", "+Inf", ErrRange}, 178 {"-3.4028236e38", "-Inf", ErrRange}, 179 // the border is 3.40282356779...e+38 180 // borderline - okay 181 {"3.402823567e38", "3.4028235e+38", nil}, 182 {"-3.402823567e38", "-3.4028235e+38", nil}, 183 // borderline - too large 184 {"3.4028235678e38", "+Inf", ErrRange}, 185 {"-3.4028235678e38", "-Inf", ErrRange}, 186 187 // Denormals: less than 2^-126 188 {"1e-38", "1e-38", nil}, 189 {"1e-39", "1e-39", nil}, 190 {"1e-40", "1e-40", nil}, 191 {"1e-41", "1e-41", nil}, 192 {"1e-42", "1e-42", nil}, 193 {"1e-43", "1e-43", nil}, 194 {"1e-44", "1e-44", nil}, 195 {"6e-45", "6e-45", nil}, // 4p-149 = 5.6e-45 196 {"5e-45", "6e-45", nil}, 197 // Smallest denormal 198 {"1e-45", "1e-45", nil}, // 1p-149 = 1.4e-45 199 {"2e-45", "1e-45", nil}, 200 201 // 2^92 = 8388608p+69 = 4951760157141521099596496896 (4.9517602e27) 202 // is an exact power of two that needs 8 decimal digits to be correctly 203 // parsed back. 204 // The float32 before is 16777215p+68 = 4.95175986e+27 205 // The halfway is 4.951760009. A bad algorithm that thinks the previous 206 // float32 is 8388607p+69 will shorten incorrectly to 4.95176e+27. 207 {"4951760157141521099596496896", "4.9517602e+27", nil}, 208 } 209 210 type atofSimpleTest struct { 211 x float64 212 s string 213 } 214 215 var ( 216 atofRandomTests []atofSimpleTest 217 benchmarksRandomBits [1024]string 218 benchmarksRandomNormal [1024]string 219 ) 220 221 func init() { 222 // The atof routines return NumErrors wrapping 223 // the error and the string. Convert the table above. 224 for i := range atoftests { 225 test := &atoftests[i] 226 if test.err != nil { 227 test.err = &NumError{"ParseFloat", test.in, test.err} 228 } 229 } 230 for i := range atof32tests { 231 test := &atof32tests[i] 232 if test.err != nil { 233 test.err = &NumError{"ParseFloat", test.in, test.err} 234 } 235 } 236 237 // Generate random inputs for tests and benchmarks 238 rand.Seed(time.Now().UnixNano()) 239 if testing.Short() { 240 atofRandomTests = make([]atofSimpleTest, 100) 241 } else { 242 atofRandomTests = make([]atofSimpleTest, 10000) 243 } 244 for i := range atofRandomTests { 245 n := uint64(rand.Uint32())<<32 | uint64(rand.Uint32()) 246 x := math.Float64frombits(n) 247 s := FormatFloat(x, 'g', -1, 64) 248 atofRandomTests[i] = atofSimpleTest{x, s} 249 } 250 251 for i := range benchmarksRandomBits { 252 bits := uint64(rand.Uint32())<<32 | uint64(rand.Uint32()) 253 x := math.Float64frombits(bits) 254 benchmarksRandomBits[i] = FormatFloat(x, 'g', -1, 64) 255 } 256 257 for i := range benchmarksRandomNormal { 258 x := rand.NormFloat64() 259 benchmarksRandomNormal[i] = FormatFloat(x, 'g', -1, 64) 260 } 261 } 262 263 func testAtof(t *testing.T, opt bool) { 264 oldopt := SetOptimize(opt) 265 for i := 0; i < len(atoftests); i++ { 266 test := &atoftests[i] 267 out, err := ParseFloat(test.in, 64) 268 outs := FormatFloat(out, 'g', -1, 64) 269 if outs != test.out || !reflect.DeepEqual(err, test.err) { 270 t.Errorf("ParseFloat(%v, 64) = %v, %v want %v, %v", 271 test.in, out, err, test.out, test.err) 272 } 273 274 if float64(float32(out)) == out { 275 out, err := ParseFloat(test.in, 32) 276 out32 := float32(out) 277 if float64(out32) != out { 278 t.Errorf("ParseFloat(%v, 32) = %v, not a float32 (closest is %v)", test.in, out, float64(out32)) 279 continue 280 } 281 outs := FormatFloat(float64(out32), 'g', -1, 32) 282 if outs != test.out || !reflect.DeepEqual(err, test.err) { 283 t.Errorf("ParseFloat(%v, 32) = %v, %v want %v, %v # %v", 284 test.in, out32, err, test.out, test.err, out) 285 } 286 } 287 } 288 for _, test := range atof32tests { 289 out, err := ParseFloat(test.in, 32) 290 out32 := float32(out) 291 if float64(out32) != out { 292 t.Errorf("ParseFloat(%v, 32) = %v, not a float32 (closest is %v)", test.in, out, float64(out32)) 293 continue 294 } 295 outs := FormatFloat(float64(out32), 'g', -1, 32) 296 if outs != test.out || !reflect.DeepEqual(err, test.err) { 297 t.Errorf("ParseFloat(%v, 32) = %v, %v want %v, %v # %v", 298 test.in, out32, err, test.out, test.err, out) 299 } 300 } 301 SetOptimize(oldopt) 302 } 303 304 func TestAtof(t *testing.T) { testAtof(t, true) } 305 306 func TestAtofSlow(t *testing.T) { testAtof(t, false) } 307 308 func TestAtofRandom(t *testing.T) { 309 for _, test := range atofRandomTests { 310 x, _ := ParseFloat(test.s, 64) 311 switch { 312 default: 313 t.Errorf("number %s badly parsed as %b (expected %b)", test.s, x, test.x) 314 case x == test.x: 315 case math.IsNaN(test.x) && math.IsNaN(x): 316 } 317 } 318 t.Logf("tested %d random numbers", len(atofRandomTests)) 319 } 320 321 var roundTripCases = []struct { 322 f float64 323 s string 324 }{ 325 // Issue 2917. 326 // This test will break the optimized conversion if the 327 // FPU is using 80-bit registers instead of 64-bit registers, 328 // usually because the operating system initialized the 329 // thread with 80-bit precision and the Go runtime didn't 330 // fix the FP control word. 331 {8865794286000691 << 39, "4.87402195346389e+27"}, 332 {8865794286000692 << 39, "4.8740219534638903e+27"}, 333 } 334 335 func TestRoundTrip(t *testing.T) { 336 for _, tt := range roundTripCases { 337 old := SetOptimize(false) 338 s := FormatFloat(tt.f, 'g', -1, 64) 339 if s != tt.s { 340 t.Errorf("no-opt FormatFloat(%b) = %s, want %s", tt.f, s, tt.s) 341 } 342 f, err := ParseFloat(tt.s, 64) 343 if f != tt.f || err != nil { 344 t.Errorf("no-opt ParseFloat(%s) = %b, %v want %b, nil", tt.s, f, err, tt.f) 345 } 346 SetOptimize(true) 347 s = FormatFloat(tt.f, 'g', -1, 64) 348 if s != tt.s { 349 t.Errorf("opt FormatFloat(%b) = %s, want %s", tt.f, s, tt.s) 350 } 351 f, err = ParseFloat(tt.s, 64) 352 if f != tt.f || err != nil { 353 t.Errorf("opt ParseFloat(%s) = %b, %v want %b, nil", tt.s, f, err, tt.f) 354 } 355 SetOptimize(old) 356 } 357 } 358 359 // TestRoundTrip32 tries a fraction of all finite positive float32 values. 360 func TestRoundTrip32(t *testing.T) { 361 step := uint32(997) 362 if testing.Short() { 363 step = 99991 364 } 365 count := 0 366 for i := uint32(0); i < 0xff<<23; i += step { 367 f := math.Float32frombits(i) 368 if i&1 == 1 { 369 f = -f // negative 370 } 371 s := FormatFloat(float64(f), 'g', -1, 32) 372 373 parsed, err := ParseFloat(s, 32) 374 parsed32 := float32(parsed) 375 switch { 376 case err != nil: 377 t.Errorf("ParseFloat(%q, 32) gave error %s", s, err) 378 case float64(parsed32) != parsed: 379 t.Errorf("ParseFloat(%q, 32) = %v, not a float32 (nearest is %v)", s, parsed, parsed32) 380 case parsed32 != f: 381 t.Errorf("ParseFloat(%q, 32) = %b (expected %b)", s, parsed32, f) 382 } 383 count++ 384 } 385 t.Logf("tested %d float32's", count) 386 } 387 388 func BenchmarkAtof64Decimal(b *testing.B) { 389 for i := 0; i < b.N; i++ { 390 ParseFloat("33909", 64) 391 } 392 } 393 394 func BenchmarkAtof64Float(b *testing.B) { 395 for i := 0; i < b.N; i++ { 396 ParseFloat("339.7784", 64) 397 } 398 } 399 400 func BenchmarkAtof64FloatExp(b *testing.B) { 401 for i := 0; i < b.N; i++ { 402 ParseFloat("-5.09e75", 64) 403 } 404 } 405 406 func BenchmarkAtof64Big(b *testing.B) { 407 for i := 0; i < b.N; i++ { 408 ParseFloat("123456789123456789123456789", 64) 409 } 410 } 411 412 func BenchmarkAtof64RandomBits(b *testing.B) { 413 for i := 0; i < b.N; i++ { 414 ParseFloat(benchmarksRandomBits[i%1024], 64) 415 } 416 } 417 418 func BenchmarkAtof64RandomFloats(b *testing.B) { 419 for i := 0; i < b.N; i++ { 420 ParseFloat(benchmarksRandomNormal[i%1024], 64) 421 } 422 } 423 424 func BenchmarkAtof32Decimal(b *testing.B) { 425 for i := 0; i < b.N; i++ { 426 ParseFloat("33909", 32) 427 } 428 } 429 430 func BenchmarkAtof32Float(b *testing.B) { 431 for i := 0; i < b.N; i++ { 432 ParseFloat("339.778", 32) 433 } 434 } 435 436 func BenchmarkAtof32FloatExp(b *testing.B) { 437 for i := 0; i < b.N; i++ { 438 ParseFloat("12.3456e32", 32) 439 } 440 } 441 442 var float32strings [4096]string 443 444 func BenchmarkAtof32Random(b *testing.B) { 445 n := uint32(997) 446 for i := range float32strings { 447 n = (99991*n + 42) % (0xff << 23) 448 float32strings[i] = FormatFloat(float64(math.Float32frombits(n)), 'g', -1, 32) 449 } 450 b.ResetTimer() 451 for i := 0; i < b.N; i++ { 452 ParseFloat(float32strings[i%4096], 32) 453 } 454 } 455
