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Issue 20652002: Fix trailing whitespace in scripts and misc. files (Closed) Base URL: svn://svn.chromium.org/blink/trunk
Patch Set: Don't change literal diff. Created 7 years, 5 months ago
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1 // Copyright 2010 the V8 project authors. All rights reserved. 1 // Copyright 2010 the V8 project authors. All rights reserved.
2 // Redistribution and use in source and binary forms, with or without 2 // Redistribution and use in source and binary forms, with or without
3 // modification, are permitted provided that the following conditions are 3 // modification, are permitted provided that the following conditions are
4 // met: 4 // met:
5 // 5 //
6 // * Redistributions of source code must retain the above copyright 6 // * Redistributions of source code must retain the above copyright
7 // notice, this list of conditions and the following disclaimer. 7 // notice, this list of conditions and the following disclaimer.
8 // * Redistributions in binary form must reproduce the above 8 // * Redistributions in binary form must reproduce the above
9 // copyright notice, this list of conditions and the following 9 // copyright notice, this list of conditions and the following
10 // disclaimer in the documentation and/or other materials provided 10 // disclaimer in the documentation and/or other materials provided
(...skipping 20 matching lines...) Expand all
31 #include <limits.h> 31 #include <limits.h>
32 32
33 #include "strtod.h" 33 #include "strtod.h"
34 #include "bignum.h" 34 #include "bignum.h"
35 #include "cached-powers.h" 35 #include "cached-powers.h"
36 #include "double.h" 36 #include "double.h"
37 37
38 namespace WTF { 38 namespace WTF {
39 39
40 namespace double_conversion { 40 namespace double_conversion {
41 41
42 // 2^53 = 9007199254740992. 42 // 2^53 = 9007199254740992.
43 // Any integer with at most 15 decimal digits will hence fit into a double 43 // Any integer with at most 15 decimal digits will hence fit into a double
44 // (which has a 53bit significand) without loss of precision. 44 // (which has a 53bit significand) without loss of precision.
45 static const int kMaxExactDoubleIntegerDecimalDigits = 15; 45 static const int kMaxExactDoubleIntegerDecimalDigits = 15;
46 // 2^64 = 18446744073709551616 > 10^19 46 // 2^64 = 18446744073709551616 > 10^19
47 static const int kMaxUint64DecimalDigits = 19; 47 static const int kMaxUint64DecimalDigits = 19;
48 48
49 // Max double: 1.7976931348623157 x 10^308 49 // Max double: 1.7976931348623157 x 10^308
50 // Min non-zero double: 4.9406564584124654 x 10^-324 50 // Min non-zero double: 4.9406564584124654 x 10^-324
51 // Any x >= 10^309 is interpreted as +infinity. 51 // Any x >= 10^309 is interpreted as +infinity.
52 // Any x <= 10^-324 is interpreted as 0. 52 // Any x <= 10^-324 is interpreted as 0.
53 // Note that 2.5e-324 (despite being smaller than the min double) will be re ad 53 // Note that 2.5e-324 (despite being smaller than the min double) will be re ad
54 // as non-zero (equal to the min non-zero double). 54 // as non-zero (equal to the min non-zero double).
55 static const int kMaxDecimalPower = 309; 55 static const int kMaxDecimalPower = 309;
56 static const int kMinDecimalPower = -324; 56 static const int kMinDecimalPower = -324;
57 57
58 // 2^64 = 18446744073709551616 58 // 2^64 = 18446744073709551616
59 static const uint64_t kMaxUint64 = UINT64_2PART_C(0xFFFFFFFF, FFFFFFFF); 59 static const uint64_t kMaxUint64 = UINT64_2PART_C(0xFFFFFFFF, FFFFFFFF);
60 60
61 61
62 static const double exact_powers_of_ten[] = { 62 static const double exact_powers_of_ten[] = {
63 1.0, // 10^0 63 1.0, // 10^0
64 10.0, 64 10.0,
65 100.0, 65 100.0,
66 1000.0, 66 1000.0,
67 10000.0, 67 10000.0,
68 100000.0, 68 100000.0,
69 1000000.0, 69 1000000.0,
70 10000000.0, 70 10000000.0,
71 100000000.0, 71 100000000.0,
72 1000000000.0, 72 1000000000.0,
73 10000000000.0, // 10^10 73 10000000000.0, // 10^10
74 100000000000.0, 74 100000000000.0,
75 1000000000000.0, 75 1000000000000.0,
76 10000000000000.0, 76 10000000000000.0,
77 100000000000000.0, 77 100000000000000.0,
78 1000000000000000.0, 78 1000000000000000.0,
79 10000000000000000.0, 79 10000000000000000.0,
80 100000000000000000.0, 80 100000000000000000.0,
81 1000000000000000000.0, 81 1000000000000000000.0,
82 10000000000000000000.0, 82 10000000000000000000.0,
83 100000000000000000000.0, // 10^20 83 100000000000000000000.0, // 10^20
84 1000000000000000000000.0, 84 1000000000000000000000.0,
85 // 10^22 = 0x21e19e0c9bab2400000 = 0x878678326eac9 * 2^22 85 // 10^22 = 0x21e19e0c9bab2400000 = 0x878678326eac9 * 2^22
86 10000000000000000000000.0 86 10000000000000000000000.0
87 }; 87 };
88 static const int kExactPowersOfTenSize = ARRAY_SIZE(exact_powers_of_ten); 88 static const int kExactPowersOfTenSize = ARRAY_SIZE(exact_powers_of_ten);
89 89
90 // Maximum number of significant digits in the decimal representation. 90 // Maximum number of significant digits in the decimal representation.
91 // In fact the value is 772 (see conversions.cc), but to give us some margin 91 // In fact the value is 772 (see conversions.cc), but to give us some margin
92 // we round up to 780. 92 // we round up to 780.
93 static const int kMaxSignificantDecimalDigits = 780; 93 static const int kMaxSignificantDecimalDigits = 780;
94 94
95 static Vector<const char> TrimLeadingZeros(Vector<const char> buffer) { 95 static Vector<const char> TrimLeadingZeros(Vector<const char> buffer) {
96 for (int i = 0; i < buffer.length(); i++) { 96 for (int i = 0; i < buffer.length(); i++) {
97 if (buffer[i] != '0') { 97 if (buffer[i] != '0') {
98 return buffer.SubVector(i, buffer.length()); 98 return buffer.SubVector(i, buffer.length());
99 } 99 }
100 } 100 }
101 return Vector<const char>(buffer.start(), 0); 101 return Vector<const char>(buffer.start(), 0);
102 } 102 }
103 103
104 104
105 static Vector<const char> TrimTrailingZeros(Vector<const char> buffer) { 105 static Vector<const char> TrimTrailingZeros(Vector<const char> buffer) {
106 for (int i = buffer.length() - 1; i >= 0; --i) { 106 for (int i = buffer.length() - 1; i >= 0; --i) {
107 if (buffer[i] != '0') { 107 if (buffer[i] != '0') {
108 return buffer.SubVector(0, i + 1); 108 return buffer.SubVector(0, i + 1);
109 } 109 }
110 } 110 }
111 return Vector<const char>(buffer.start(), 0); 111 return Vector<const char>(buffer.start(), 0);
112 } 112 }
113 113
114 114
115 static void TrimToMaxSignificantDigits(Vector<const char> buffer, 115 static void TrimToMaxSignificantDigits(Vector<const char> buffer,
116 int exponent, 116 int exponent,
117 char* significant_buffer, 117 char* significant_buffer,
118 int* significant_exponent) { 118 int* significant_exponent) {
119 for (int i = 0; i < kMaxSignificantDecimalDigits - 1; ++i) { 119 for (int i = 0; i < kMaxSignificantDecimalDigits - 1; ++i) {
120 significant_buffer[i] = buffer[i]; 120 significant_buffer[i] = buffer[i];
121 } 121 }
122 // The input buffer has been trimmed. Therefore the last digit must be 122 // The input buffer has been trimmed. Therefore the last digit must be
123 // different from '0'. 123 // different from '0'.
124 ASSERT(buffer[buffer.length() - 1] != '0'); 124 ASSERT(buffer[buffer.length() - 1] != '0');
125 // Set the last digit to be non-zero. This is sufficient to guarantee 125 // Set the last digit to be non-zero. This is sufficient to guarantee
126 // correct rounding. 126 // correct rounding.
127 significant_buffer[kMaxSignificantDecimalDigits - 1] = '1'; 127 significant_buffer[kMaxSignificantDecimalDigits - 1] = '1';
128 *significant_exponent = 128 *significant_exponent =
129 exponent + (buffer.length() - kMaxSignificantDecimalDigits); 129 exponent + (buffer.length() - kMaxSignificantDecimalDigits);
130 } 130 }
131 131
132 // Reads digits from the buffer and converts them to a uint64. 132 // Reads digits from the buffer and converts them to a uint64.
133 // Reads in as many digits as fit into a uint64. 133 // Reads in as many digits as fit into a uint64.
134 // When the string starts with "1844674407370955161" no further digit is rea d. 134 // When the string starts with "1844674407370955161" no further digit is rea d.
135 // Since 2^64 = 18446744073709551616 it would still be possible read another 135 // Since 2^64 = 18446744073709551616 it would still be possible read another
136 // digit if it was less or equal than 6, but this would complicate the code. 136 // digit if it was less or equal than 6, but this would complicate the code.
137 static uint64_t ReadUint64(Vector<const char> buffer, 137 static uint64_t ReadUint64(Vector<const char> buffer,
138 int* number_of_read_digits) { 138 int* number_of_read_digits) {
139 uint64_t result = 0; 139 uint64_t result = 0;
140 int i = 0; 140 int i = 0;
141 while (i < buffer.length() && result <= (kMaxUint64 / 10 - 1)) { 141 while (i < buffer.length() && result <= (kMaxUint64 / 10 - 1)) {
142 int digit = buffer[i++] - '0'; 142 int digit = buffer[i++] - '0';
143 ASSERT(0 <= digit && digit <= 9); 143 ASSERT(0 <= digit && digit <= 9);
144 result = 10 * result + digit; 144 result = 10 * result + digit;
145 } 145 }
146 *number_of_read_digits = i; 146 *number_of_read_digits = i;
147 return result; 147 return result;
148 } 148 }
149 149
150 150
151 // Reads a DiyFp from the buffer. 151 // Reads a DiyFp from the buffer.
152 // The returned DiyFp is not necessarily normalized. 152 // The returned DiyFp is not necessarily normalized.
153 // If remaining_decimals is zero then the returned DiyFp is accurate. 153 // If remaining_decimals is zero then the returned DiyFp is accurate.
154 // Otherwise it has been rounded and has error of at most 1/2 ulp. 154 // Otherwise it has been rounded and has error of at most 1/2 ulp.
155 static void ReadDiyFp(Vector<const char> buffer, 155 static void ReadDiyFp(Vector<const char> buffer,
156 DiyFp* result, 156 DiyFp* result,
157 int* remaining_decimals) { 157 int* remaining_decimals) {
158 int read_digits; 158 int read_digits;
159 uint64_t significand = ReadUint64(buffer, &read_digits); 159 uint64_t significand = ReadUint64(buffer, &read_digits);
160 if (buffer.length() == read_digits) { 160 if (buffer.length() == read_digits) {
161 *result = DiyFp(significand, 0); 161 *result = DiyFp(significand, 0);
162 *remaining_decimals = 0; 162 *remaining_decimals = 0;
163 } else { 163 } else {
164 // Round the significand. 164 // Round the significand.
165 if (buffer[read_digits] >= '5') { 165 if (buffer[read_digits] >= '5') {
166 significand++; 166 significand++;
167 } 167 }
168 // Compute the binary exponent. 168 // Compute the binary exponent.
169 int exponent = 0; 169 int exponent = 0;
170 *result = DiyFp(significand, exponent); 170 *result = DiyFp(significand, exponent);
171 *remaining_decimals = buffer.length() - read_digits; 171 *remaining_decimals = buffer.length() - read_digits;
172 } 172 }
173 } 173 }
174 174
175 175
176 static bool DoubleStrtod(Vector<const char> trimmed, 176 static bool DoubleStrtod(Vector<const char> trimmed,
177 int exponent, 177 int exponent,
178 double* result) { 178 double* result) {
179 #if !defined(DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS) 179 #if !defined(DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS)
180 // On x86 the floating-point stack can be 64 or 80 bits wide. If it is 180 // On x86 the floating-point stack can be 64 or 80 bits wide. If it is
181 // 80 bits wide (as is the case on Linux) then double-rounding occurs an d the 181 // 80 bits wide (as is the case on Linux) then double-rounding occurs an d the
182 // result is not accurate. 182 // result is not accurate.
183 // We know that Windows32 uses 64 bits and is therefore accurate. 183 // We know that Windows32 uses 64 bits and is therefore accurate.
184 // Note that the ARM simulator is compiled for 32bits. It therefore exhi bits 184 // Note that the ARM simulator is compiled for 32bits. It therefore exhi bits
185 // the same problem. 185 // the same problem.
(...skipping 30 matching lines...) Expand all
216 // into a double too. 216 // into a double too.
217 *result = static_cast<double>(ReadUint64(trimmed, &read_digits)) ; 217 *result = static_cast<double>(ReadUint64(trimmed, &read_digits)) ;
218 ASSERT(read_digits == trimmed.length()); 218 ASSERT(read_digits == trimmed.length());
219 *result *= exact_powers_of_ten[remaining_digits]; 219 *result *= exact_powers_of_ten[remaining_digits];
220 *result *= exact_powers_of_ten[exponent - remaining_digits]; 220 *result *= exact_powers_of_ten[exponent - remaining_digits];
221 return true; 221 return true;
222 } 222 }
223 } 223 }
224 return false; 224 return false;
225 } 225 }
226 226
227 227
228 // Returns 10^exponent as an exact DiyFp. 228 // Returns 10^exponent as an exact DiyFp.
229 // The given exponent must be in the range [1; kDecimalExponentDistance[. 229 // The given exponent must be in the range [1; kDecimalExponentDistance[.
230 static DiyFp AdjustmentPowerOfTen(int exponent) { 230 static DiyFp AdjustmentPowerOfTen(int exponent) {
231 ASSERT(0 < exponent); 231 ASSERT(0 < exponent);
232 ASSERT(exponent < PowersOfTenCache::kDecimalExponentDistance); 232 ASSERT(exponent < PowersOfTenCache::kDecimalExponentDistance);
233 // Simply hardcode the remaining powers for the given decimal exponent 233 // Simply hardcode the remaining powers for the given decimal exponent
234 // distance. 234 // distance.
235 ASSERT(PowersOfTenCache::kDecimalExponentDistance == 8); 235 ASSERT(PowersOfTenCache::kDecimalExponentDistance == 8);
236 switch (exponent) { 236 switch (exponent) {
237 case 1: return DiyFp(UINT64_2PART_C(0xa0000000, 00000000), -60); 237 case 1: return DiyFp(UINT64_2PART_C(0xa0000000, 00000000), -60);
238 case 2: return DiyFp(UINT64_2PART_C(0xc8000000, 00000000), -57); 238 case 2: return DiyFp(UINT64_2PART_C(0xc8000000, 00000000), -57);
239 case 3: return DiyFp(UINT64_2PART_C(0xfa000000, 00000000), -54); 239 case 3: return DiyFp(UINT64_2PART_C(0xfa000000, 00000000), -54);
240 case 4: return DiyFp(UINT64_2PART_C(0x9c400000, 00000000), -50); 240 case 4: return DiyFp(UINT64_2PART_C(0x9c400000, 00000000), -50);
241 case 5: return DiyFp(UINT64_2PART_C(0xc3500000, 00000000), -47); 241 case 5: return DiyFp(UINT64_2PART_C(0xc3500000, 00000000), -47);
242 case 6: return DiyFp(UINT64_2PART_C(0xf4240000, 00000000), -44); 242 case 6: return DiyFp(UINT64_2PART_C(0xf4240000, 00000000), -44);
243 case 7: return DiyFp(UINT64_2PART_C(0x98968000, 00000000), -40); 243 case 7: return DiyFp(UINT64_2PART_C(0x98968000, 00000000), -40);
244 default: 244 default:
245 UNREACHABLE(); 245 UNREACHABLE();
246 return DiyFp(0, 0); 246 return DiyFp(0, 0);
247 } 247 }
248 } 248 }
249 249
250 250
251 // If the function returns true then the result is the correct double. 251 // If the function returns true then the result is the correct double.
252 // Otherwise it is either the correct double or the double that is just belo w 252 // Otherwise it is either the correct double or the double that is just belo w
253 // the correct double. 253 // the correct double.
254 static bool DiyFpStrtod(Vector<const char> buffer, 254 static bool DiyFpStrtod(Vector<const char> buffer,
255 int exponent, 255 int exponent,
256 double* result) { 256 double* result) {
257 DiyFp input; 257 DiyFp input;
258 int remaining_decimals; 258 int remaining_decimals;
259 ReadDiyFp(buffer, &input, &remaining_decimals); 259 ReadDiyFp(buffer, &input, &remaining_decimals);
260 // Since we may have dropped some digits the input is not accurate. 260 // Since we may have dropped some digits the input is not accurate.
261 // If remaining_decimals is different than 0 than the error is at most 261 // If remaining_decimals is different than 0 than the error is at most
262 // .5 ulp (unit in the last place). 262 // .5 ulp (unit in the last place).
263 // We don't want to deal with fractions and therefore keep a common 263 // We don't want to deal with fractions and therefore keep a common
264 // denominator. 264 // denominator.
265 const int kDenominatorLog = 3; 265 const int kDenominatorLog = 3;
266 const int kDenominator = 1 << kDenominatorLog; 266 const int kDenominator = 1 << kDenominatorLog;
267 // Move the remaining decimals into the exponent. 267 // Move the remaining decimals into the exponent.
268 exponent += remaining_decimals; 268 exponent += remaining_decimals;
269 int error = (remaining_decimals == 0 ? 0 : kDenominator / 2); 269 int error = (remaining_decimals == 0 ? 0 : kDenominator / 2);
270 270
271 int old_e = input.e(); 271 int old_e = input.e();
272 input.Normalize(); 272 input.Normalize();
273 error <<= old_e - input.e(); 273 error <<= old_e - input.e();
274 274
275 ASSERT(exponent <= PowersOfTenCache::kMaxDecimalExponent); 275 ASSERT(exponent <= PowersOfTenCache::kMaxDecimalExponent);
276 if (exponent < PowersOfTenCache::kMinDecimalExponent) { 276 if (exponent < PowersOfTenCache::kMinDecimalExponent) {
277 *result = 0.0; 277 *result = 0.0;
278 return true; 278 return true;
279 } 279 }
280 DiyFp cached_power; 280 DiyFp cached_power;
281 int cached_decimal_exponent; 281 int cached_decimal_exponent;
282 PowersOfTenCache::GetCachedPowerForDecimalExponent(exponent, 282 PowersOfTenCache::GetCachedPowerForDecimalExponent(exponent,
283 &cached_power, 283 &cached_power,
284 &cached_decimal_expon ent); 284 &cached_decimal_expon ent);
285 285
286 if (cached_decimal_exponent != exponent) { 286 if (cached_decimal_exponent != exponent) {
287 int adjustment_exponent = exponent - cached_decimal_exponent; 287 int adjustment_exponent = exponent - cached_decimal_exponent;
288 DiyFp adjustment_power = AdjustmentPowerOfTen(adjustment_exponent); 288 DiyFp adjustment_power = AdjustmentPowerOfTen(adjustment_exponent);
289 input.Multiply(adjustment_power); 289 input.Multiply(adjustment_power);
290 if (kMaxUint64DecimalDigits - buffer.length() >= adjustment_exponent ) { 290 if (kMaxUint64DecimalDigits - buffer.length() >= adjustment_exponent ) {
291 // The product of input with the adjustment power fits into a 64 bit 291 // The product of input with the adjustment power fits into a 64 bit
292 // integer. 292 // integer.
293 ASSERT(DiyFp::kSignificandSize == 64); 293 ASSERT(DiyFp::kSignificandSize == 64);
294 } else { 294 } else {
295 // The adjustment power is exact. There is hence only an error o f 0.5. 295 // The adjustment power is exact. There is hence only an error o f 0.5.
296 error += kDenominator / 2; 296 error += kDenominator / 2;
297 } 297 }
298 } 298 }
299 299
300 input.Multiply(cached_power); 300 input.Multiply(cached_power);
301 // The error introduced by a multiplication of a*b equals 301 // The error introduced by a multiplication of a*b equals
302 // error_a + error_b + error_a*error_b/2^64 + 0.5 302 // error_a + error_b + error_a*error_b/2^64 + 0.5
303 // Substituting a with 'input' and b with 'cached_power' we have 303 // Substituting a with 'input' and b with 'cached_power' we have
304 // error_b = 0.5 (all cached powers have an error of less than 0.5 ul p), 304 // error_b = 0.5 (all cached powers have an error of less than 0.5 ul p),
305 // error_ab = 0 or 1 / kDenominator > error_a*error_b/ 2^64 305 // error_ab = 0 or 1 / kDenominator > error_a*error_b/ 2^64
306 int error_b = kDenominator / 2; 306 int error_b = kDenominator / 2;
307 int error_ab = (error == 0 ? 0 : 1); // We round up to 1. 307 int error_ab = (error == 0 ? 0 : 1); // We round up to 1.
308 int fixed_error = kDenominator / 2; 308 int fixed_error = kDenominator / 2;
309 error += error_b + error_ab + fixed_error; 309 error += error_b + error_ab + fixed_error;
310 310
311 old_e = input.e(); 311 old_e = input.e();
312 input.Normalize(); 312 input.Normalize();
313 error <<= old_e - input.e(); 313 error <<= old_e - input.e();
314 314
315 // See if the double's significand changes if we add/subtract the error. 315 // See if the double's significand changes if we add/subtract the error.
316 int order_of_magnitude = DiyFp::kSignificandSize + input.e(); 316 int order_of_magnitude = DiyFp::kSignificandSize + input.e();
317 int effective_significand_size = 317 int effective_significand_size =
318 Double::SignificandSizeForOrderOfMagnitude(order_of_magnitude); 318 Double::SignificandSizeForOrderOfMagnitude(order_of_magnitude);
319 int precision_digits_count = 319 int precision_digits_count =
320 DiyFp::kSignificandSize - effective_significand_size; 320 DiyFp::kSignificandSize - effective_significand_size;
321 if (precision_digits_count + kDenominatorLog >= DiyFp::kSignificandSize) { 321 if (precision_digits_count + kDenominatorLog >= DiyFp::kSignificandSize) {
322 // This can only happen for very small denormals. In this case the 322 // This can only happen for very small denormals. In this case the
323 // half-way multiplied by the denominator exceeds the range of an ui nt64. 323 // half-way multiplied by the denominator exceeds the range of an ui nt64.
324 // Simply shift everything to the right. 324 // Simply shift everything to the right.
(...skipping 16 matching lines...) Expand all
341 precision_bits *= kDenominator; 341 precision_bits *= kDenominator;
342 half_way *= kDenominator; 342 half_way *= kDenominator;
343 DiyFp rounded_input(input.f() >> precision_digits_count, 343 DiyFp rounded_input(input.f() >> precision_digits_count,
344 input.e() + precision_digits_count); 344 input.e() + precision_digits_count);
345 if (precision_bits >= half_way + error) { 345 if (precision_bits >= half_way + error) {
346 rounded_input.set_f(rounded_input.f() + 1); 346 rounded_input.set_f(rounded_input.f() + 1);
347 } 347 }
348 // If the last_bits are too close to the half-way case than we are too 348 // If the last_bits are too close to the half-way case than we are too
349 // inaccurate and round down. In this case we return false so that we ca n 349 // inaccurate and round down. In this case we return false so that we ca n
350 // fall back to a more precise algorithm. 350 // fall back to a more precise algorithm.
351 351
352 *result = Double(rounded_input).value(); 352 *result = Double(rounded_input).value();
353 if (half_way - error < precision_bits && precision_bits < half_way + err or) { 353 if (half_way - error < precision_bits && precision_bits < half_way + err or) {
354 // Too imprecise. The caller will have to fall back to a slower vers ion. 354 // Too imprecise. The caller will have to fall back to a slower vers ion.
355 // However the returned number is guaranteed to be either the correc t 355 // However the returned number is guaranteed to be either the correc t
356 // double, or the next-lower double. 356 // double, or the next-lower double.
357 return false; 357 return false;
358 } else { 358 } else {
359 return true; 359 return true;
360 } 360 }
361 } 361 }
362 362
363 363
364 // Returns the correct double for the buffer*10^exponent. 364 // Returns the correct double for the buffer*10^exponent.
365 // The variable guess should be a close guess that is either the correct dou ble 365 // The variable guess should be a close guess that is either the correct dou ble
366 // or its lower neighbor (the nearest double less than the correct one). 366 // or its lower neighbor (the nearest double less than the correct one).
367 // Preconditions: 367 // Preconditions:
368 // buffer.length() + exponent <= kMaxDecimalPower + 1 368 // buffer.length() + exponent <= kMaxDecimalPower + 1
369 // buffer.length() + exponent > kMinDecimalPower 369 // buffer.length() + exponent > kMinDecimalPower
370 // buffer.length() <= kMaxDecimalSignificantDigits 370 // buffer.length() <= kMaxDecimalSignificantDigits
371 static double BignumStrtod(Vector<const char> buffer, 371 static double BignumStrtod(Vector<const char> buffer,
372 int exponent, 372 int exponent,
373 double guess) { 373 double guess) {
374 if (guess == Double::Infinity()) { 374 if (guess == Double::Infinity()) {
375 return guess; 375 return guess;
376 } 376 }
377 377
378 DiyFp upper_boundary = Double(guess).UpperBoundary(); 378 DiyFp upper_boundary = Double(guess).UpperBoundary();
379 379
380 ASSERT(buffer.length() + exponent <= kMaxDecimalPower + 1); 380 ASSERT(buffer.length() + exponent <= kMaxDecimalPower + 1);
381 ASSERT(buffer.length() + exponent > kMinDecimalPower); 381 ASSERT(buffer.length() + exponent > kMinDecimalPower);
382 ASSERT(buffer.length() <= kMaxSignificantDecimalDigits); 382 ASSERT(buffer.length() <= kMaxSignificantDecimalDigits);
383 // Make sure that the Bignum will be able to hold all our numbers. 383 // Make sure that the Bignum will be able to hold all our numbers.
384 // Our Bignum implementation has a separate field for exponents. Shifts will 384 // Our Bignum implementation has a separate field for exponents. Shifts will
385 // consume at most one bigit (< 64 bits). 385 // consume at most one bigit (< 64 bits).
386 // ln(10) == 3.3219... 386 // ln(10) == 3.3219...
387 ASSERT(((kMaxDecimalPower + 1) * 333 / 100) < Bignum::kMaxSignificantBit s); 387 ASSERT(((kMaxDecimalPower + 1) * 333 / 100) < Bignum::kMaxSignificantBit s);
388 Bignum input; 388 Bignum input;
389 Bignum boundary; 389 Bignum boundary;
(...skipping 14 matching lines...) Expand all
404 return guess; 404 return guess;
405 } else if (comparison > 0) { 405 } else if (comparison > 0) {
406 return Double(guess).NextDouble(); 406 return Double(guess).NextDouble();
407 } else if ((Double(guess).Significand() & 1) == 0) { 407 } else if ((Double(guess).Significand() & 1) == 0) {
408 // Round towards even. 408 // Round towards even.
409 return guess; 409 return guess;
410 } else { 410 } else {
411 return Double(guess).NextDouble(); 411 return Double(guess).NextDouble();
412 } 412 }
413 } 413 }
414 414
415 415
416 double Strtod(Vector<const char> buffer, int exponent) { 416 double Strtod(Vector<const char> buffer, int exponent) {
417 Vector<const char> left_trimmed = TrimLeadingZeros(buffer); 417 Vector<const char> left_trimmed = TrimLeadingZeros(buffer);
418 Vector<const char> trimmed = TrimTrailingZeros(left_trimmed); 418 Vector<const char> trimmed = TrimTrailingZeros(left_trimmed);
419 exponent += left_trimmed.length() - trimmed.length(); 419 exponent += left_trimmed.length() - trimmed.length();
420 if (trimmed.length() == 0) return 0.0; 420 if (trimmed.length() == 0) return 0.0;
421 if (trimmed.length() > kMaxSignificantDecimalDigits) { 421 if (trimmed.length() > kMaxSignificantDecimalDigits) {
422 char significant_buffer[kMaxSignificantDecimalDigits]; 422 char significant_buffer[kMaxSignificantDecimalDigits];
423 int significant_exponent; 423 int significant_exponent;
424 TrimToMaxSignificantDigits(trimmed, exponent, 424 TrimToMaxSignificantDigits(trimmed, exponent,
425 significant_buffer, &significant_exponent ); 425 significant_buffer, &significant_exponent );
426 return Strtod(Vector<const char>(significant_buffer, 426 return Strtod(Vector<const char>(significant_buffer,
427 kMaxSignificantDecimalDigits), 427 kMaxSignificantDecimalDigits),
428 significant_exponent); 428 significant_exponent);
429 } 429 }
430 if (exponent + trimmed.length() - 1 >= kMaxDecimalPower) { 430 if (exponent + trimmed.length() - 1 >= kMaxDecimalPower) {
431 return Double::Infinity(); 431 return Double::Infinity();
432 } 432 }
433 if (exponent + trimmed.length() <= kMinDecimalPower) { 433 if (exponent + trimmed.length() <= kMinDecimalPower) {
434 return 0.0; 434 return 0.0;
435 } 435 }
436 436
437 double guess; 437 double guess;
438 if (DoubleStrtod(trimmed, exponent, &guess) || 438 if (DoubleStrtod(trimmed, exponent, &guess) ||
439 DiyFpStrtod(trimmed, exponent, &guess)) { 439 DiyFpStrtod(trimmed, exponent, &guess)) {
440 return guess; 440 return guess;
441 } 441 }
442 return BignumStrtod(trimmed, exponent, guess); 442 return BignumStrtod(trimmed, exponent, guess);
443 } 443 }
444 444
445 } // namespace double_conversion 445 } // namespace double_conversion
446 446
447 } // namespace WTF 447 } // namespace WTF
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