1 // Copyright 2006-2008 the V8 project authors. All rights reserved.
2
3 #include <stdlib.h>
4
5 #include "v8.h"
6
7 #include "platform.h"
8 #include "cctest.h"
9 #include "diy-fp.h"
10 #include "double.h"
11 #include "fast-dtoa.h"
12 #include "gay-precision.h"
13 #include "gay-shortest.h"
14
15 using namespace v8::internal;
16
17 static const int kBufferSize = 100;
18
19
20 // Removes trailing '0' digits.
TrimRepresentation(Vector<char> representation)21 static void TrimRepresentation(Vector<char> representation) {
22 int len = StrLength(representation.start());
23 int i;
24 for (i = len - 1; i >= 0; --i) {
25 if (representation[i] != '0') break;
26 }
27 representation[i + 1] = '\0';
28 }
29
30
TEST(FastDtoaShortestVariousDoubles)31 TEST(FastDtoaShortestVariousDoubles) {
32 char buffer_container[kBufferSize];
33 Vector<char> buffer(buffer_container, kBufferSize);
34 int length;
35 int point;
36 int status;
37
38 double min_double = 5e-324;
39 status = FastDtoa(min_double, FAST_DTOA_SHORTEST, 0,
40 buffer, &length, &point);
41 CHECK(status);
42 CHECK_EQ("5", buffer.start());
43 CHECK_EQ(-323, point);
44
45 double max_double = 1.7976931348623157e308;
46 status = FastDtoa(max_double, FAST_DTOA_SHORTEST, 0,
47 buffer, &length, &point);
48 CHECK(status);
49 CHECK_EQ("17976931348623157", buffer.start());
50 CHECK_EQ(309, point);
51
52 status = FastDtoa(4294967272.0, FAST_DTOA_SHORTEST, 0,
53 buffer, &length, &point);
54 CHECK(status);
55 CHECK_EQ("4294967272", buffer.start());
56 CHECK_EQ(10, point);
57
58 status = FastDtoa(4.1855804968213567e298, FAST_DTOA_SHORTEST, 0,
59 buffer, &length, &point);
60 CHECK(status);
61 CHECK_EQ("4185580496821357", buffer.start());
62 CHECK_EQ(299, point);
63
64 status = FastDtoa(5.5626846462680035e-309, FAST_DTOA_SHORTEST, 0,
65 buffer, &length, &point);
66 CHECK(status);
67 CHECK_EQ("5562684646268003", buffer.start());
68 CHECK_EQ(-308, point);
69
70 status = FastDtoa(2147483648.0, FAST_DTOA_SHORTEST, 0,
71 buffer, &length, &point);
72 CHECK(status);
73 CHECK_EQ("2147483648", buffer.start());
74 CHECK_EQ(10, point);
75
76 status = FastDtoa(3.5844466002796428e+298, FAST_DTOA_SHORTEST, 0,
77 buffer, &length, &point);
78 if (status) { // Not all FastDtoa variants manage to compute this number.
79 CHECK_EQ("35844466002796428", buffer.start());
80 CHECK_EQ(299, point);
81 }
82
83 uint64_t smallest_normal64 = V8_2PART_UINT64_C(0x00100000, 00000000);
84 double v = Double(smallest_normal64).value();
85 status = FastDtoa(v, FAST_DTOA_SHORTEST, 0, buffer, &length, &point);
86 if (status) {
87 CHECK_EQ("22250738585072014", buffer.start());
88 CHECK_EQ(-307, point);
89 }
90
91 uint64_t largest_denormal64 = V8_2PART_UINT64_C(0x000FFFFF, FFFFFFFF);
92 v = Double(largest_denormal64).value();
93 status = FastDtoa(v, FAST_DTOA_SHORTEST, 0, buffer, &length, &point);
94 if (status) {
95 CHECK_EQ("2225073858507201", buffer.start());
96 CHECK_EQ(-307, point);
97 }
98 }
99
100
TEST(FastDtoaPrecisionVariousDoubles)101 TEST(FastDtoaPrecisionVariousDoubles) {
102 char buffer_container[kBufferSize];
103 Vector<char> buffer(buffer_container, kBufferSize);
104 int length;
105 int point;
106 int status;
107
108 status = FastDtoa(1.0, FAST_DTOA_PRECISION, 3, buffer, &length, &point);
109 CHECK(status);
110 CHECK_GE(3, length);
111 TrimRepresentation(buffer);
112 CHECK_EQ("1", buffer.start());
113 CHECK_EQ(1, point);
114
115 status = FastDtoa(1.5, FAST_DTOA_PRECISION, 10, buffer, &length, &point);
116 if (status) {
117 CHECK_GE(10, length);
118 TrimRepresentation(buffer);
119 CHECK_EQ("15", buffer.start());
120 CHECK_EQ(1, point);
121 }
122
123 double min_double = 5e-324;
124 status = FastDtoa(min_double, FAST_DTOA_PRECISION, 5,
125 buffer, &length, &point);
126 CHECK(status);
127 CHECK_EQ("49407", buffer.start());
128 CHECK_EQ(-323, point);
129
130 double max_double = 1.7976931348623157e308;
131 status = FastDtoa(max_double, FAST_DTOA_PRECISION, 7,
132 buffer, &length, &point);
133 CHECK(status);
134 CHECK_EQ("1797693", buffer.start());
135 CHECK_EQ(309, point);
136
137 status = FastDtoa(4294967272.0, FAST_DTOA_PRECISION, 14,
138 buffer, &length, &point);
139 if (status) {
140 CHECK_GE(14, length);
141 TrimRepresentation(buffer);
142 CHECK_EQ("4294967272", buffer.start());
143 CHECK_EQ(10, point);
144 }
145
146 status = FastDtoa(4.1855804968213567e298, FAST_DTOA_PRECISION, 17,
147 buffer, &length, &point);
148 CHECK(status);
149 CHECK_EQ("41855804968213567", buffer.start());
150 CHECK_EQ(299, point);
151
152 status = FastDtoa(5.5626846462680035e-309, FAST_DTOA_PRECISION, 1,
153 buffer, &length, &point);
154 CHECK(status);
155 CHECK_EQ("6", buffer.start());
156 CHECK_EQ(-308, point);
157
158 status = FastDtoa(2147483648.0, FAST_DTOA_PRECISION, 5,
159 buffer, &length, &point);
160 CHECK(status);
161 CHECK_EQ("21475", buffer.start());
162 CHECK_EQ(10, point);
163
164 status = FastDtoa(3.5844466002796428e+298, FAST_DTOA_PRECISION, 10,
165 buffer, &length, &point);
166 CHECK(status);
167 CHECK_GE(10, length);
168 TrimRepresentation(buffer);
169 CHECK_EQ("35844466", buffer.start());
170 CHECK_EQ(299, point);
171
172 uint64_t smallest_normal64 = V8_2PART_UINT64_C(0x00100000, 00000000);
173 double v = Double(smallest_normal64).value();
174 status = FastDtoa(v, FAST_DTOA_PRECISION, 17, buffer, &length, &point);
175 CHECK(status);
176 CHECK_EQ("22250738585072014", buffer.start());
177 CHECK_EQ(-307, point);
178
179 uint64_t largest_denormal64 = V8_2PART_UINT64_C(0x000FFFFF, FFFFFFFF);
180 v = Double(largest_denormal64).value();
181 status = FastDtoa(v, FAST_DTOA_PRECISION, 17, buffer, &length, &point);
182 CHECK(status);
183 CHECK_GE(20, length);
184 TrimRepresentation(buffer);
185 CHECK_EQ("22250738585072009", buffer.start());
186 CHECK_EQ(-307, point);
187
188 v = 3.3161339052167390562200598e-237;
189 status = FastDtoa(v, FAST_DTOA_PRECISION, 18, buffer, &length, &point);
190 CHECK(status);
191 CHECK_EQ("331613390521673906", buffer.start());
192 CHECK_EQ(-236, point);
193
194 v = 7.9885183916008099497815232e+191;
195 status = FastDtoa(v, FAST_DTOA_PRECISION, 4, buffer, &length, &point);
196 CHECK(status);
197 CHECK_EQ("7989", buffer.start());
198 CHECK_EQ(192, point);
199 }
200
201
TEST(FastDtoaGayShortest)202 TEST(FastDtoaGayShortest) {
203 char buffer_container[kBufferSize];
204 Vector<char> buffer(buffer_container, kBufferSize);
205 bool status;
206 int length;
207 int point;
208 int succeeded = 0;
209 int total = 0;
210 bool needed_max_length = false;
211
212 Vector<const PrecomputedShortest> precomputed =
213 PrecomputedShortestRepresentations();
214 for (int i = 0; i < precomputed.length(); ++i) {
215 const PrecomputedShortest current_test = precomputed[i];
216 total++;
217 double v = current_test.v;
218 status = FastDtoa(v, FAST_DTOA_SHORTEST, 0, buffer, &length, &point);
219 CHECK_GE(kFastDtoaMaximalLength, length);
220 if (!status) continue;
221 if (length == kFastDtoaMaximalLength) needed_max_length = true;
222 succeeded++;
223 CHECK_EQ(current_test.decimal_point, point);
224 CHECK_EQ(current_test.representation, buffer.start());
225 }
226 CHECK_GT(succeeded*1.0/total, 0.99);
227 CHECK(needed_max_length);
228 }
229
230
TEST(FastDtoaGayPrecision)231 TEST(FastDtoaGayPrecision) {
232 char buffer_container[kBufferSize];
233 Vector<char> buffer(buffer_container, kBufferSize);
234 bool status;
235 int length;
236 int point;
237 int succeeded = 0;
238 int total = 0;
239 // Count separately for entries with less than 15 requested digits.
240 int succeeded_15 = 0;
241 int total_15 = 0;
242
243 Vector<const PrecomputedPrecision> precomputed =
244 PrecomputedPrecisionRepresentations();
245 for (int i = 0; i < precomputed.length(); ++i) {
246 const PrecomputedPrecision current_test = precomputed[i];
247 double v = current_test.v;
248 int number_digits = current_test.number_digits;
249 total++;
250 if (number_digits <= 15) total_15++;
251 status = FastDtoa(v, FAST_DTOA_PRECISION, number_digits,
252 buffer, &length, &point);
253 CHECK_GE(number_digits, length);
254 if (!status) continue;
255 succeeded++;
256 if (number_digits <= 15) succeeded_15++;
257 TrimRepresentation(buffer);
258 CHECK_EQ(current_test.decimal_point, point);
259 CHECK_EQ(current_test.representation, buffer.start());
260 }
261 // The precomputed numbers contain many entries with many requested
262 // digits. These have a high failure rate and we therefore expect a lower
263 // success rate than for the shortest representation.
264 CHECK_GT(succeeded*1.0/total, 0.85);
265 // However with less than 15 digits almost the algorithm should almost always
266 // succeed.
267 CHECK_GT(succeeded_15*1.0/total_15, 0.9999);
268 }
269