template< -> template <
[folly.git] / folly / test / ConvTest.cpp
1 /*
2  * Copyright 2017 Facebook, Inc.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *   http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 #ifndef __STDC_FORMAT_MACROS
18 #define __STDC_FORMAT_MACROS 1
19 #endif
20
21 #include <boost/lexical_cast.hpp>
22
23 #include <folly/Conv.h>
24 #include <folly/Foreach.h>
25 #include <folly/portability/GTest.h>
26
27 #include <algorithm>
28 #include <cinttypes>
29 #include <limits>
30 #include <sstream>
31 #include <stdexcept>
32 #include <tuple>
33
34 using namespace std;
35 using namespace folly;
36
37
38 TEST(Conv, digits10) {
39   char buffer[100];
40   uint64_t power;
41
42   // first, some basic sniff tests
43   EXPECT_EQ( 1, digits10(0));
44   EXPECT_EQ( 1, digits10(1));
45   EXPECT_EQ( 1, digits10(9));
46   EXPECT_EQ( 2, digits10(10));
47   EXPECT_EQ( 2, digits10(99));
48   EXPECT_EQ( 3, digits10(100));
49   EXPECT_EQ( 3, digits10(999));
50   EXPECT_EQ( 4, digits10(1000));
51   EXPECT_EQ( 4, digits10(9999));
52   EXPECT_EQ(20, digits10(18446744073709551615ULL));
53
54   // try the first X nonnegatives.
55   // Covers some more cases of 2^p, 10^p
56   for (uint64_t i = 0; i < 100000; i++) {
57     snprintf(buffer, sizeof(buffer), "%" PRIu64, i);
58     EXPECT_EQ(strlen(buffer), digits10(i));
59   }
60
61   // try powers of 2
62   power = 1;
63   for (int p = 0; p < 64; p++) {
64     snprintf(buffer, sizeof(buffer), "%" PRIu64, power);
65     EXPECT_EQ(strlen(buffer), digits10(power));
66     snprintf(buffer, sizeof(buffer), "%" PRIu64, power - 1);
67     EXPECT_EQ(strlen(buffer), digits10(power - 1));
68     snprintf(buffer, sizeof(buffer), "%" PRIu64, power + 1);
69     EXPECT_EQ(strlen(buffer), digits10(power + 1));
70     power *= 2;
71   }
72
73   // try powers of 10
74   power = 1;
75   for (int p = 0; p < 20; p++) {
76     snprintf(buffer, sizeof(buffer), "%" PRIu64, power);
77     EXPECT_EQ(strlen(buffer), digits10(power));
78     snprintf(buffer, sizeof(buffer), "%" PRIu64, power - 1);
79     EXPECT_EQ(strlen(buffer), digits10(power - 1));
80     snprintf(buffer, sizeof(buffer), "%" PRIu64, power + 1);
81     EXPECT_EQ(strlen(buffer), digits10(power + 1));
82     power *= 10;
83   }
84 }
85
86 // Test to<T>(T)
87 TEST(Conv, Type2Type) {
88   bool boolV = true;
89   EXPECT_EQ(to<bool>(boolV), true);
90
91   int intV = 42;
92   EXPECT_EQ(to<int>(intV), 42);
93
94   float floatV = 4.2f;
95   EXPECT_EQ(to<float>(floatV), 4.2f);
96
97   double doubleV = 0.42;
98   EXPECT_EQ(to<double>(doubleV), 0.42);
99
100   std::string stringV = "StdString";
101   EXPECT_EQ(to<std::string>(stringV), "StdString");
102
103   folly::fbstring fbStrV = "FBString";
104   EXPECT_EQ(to<folly::fbstring>(fbStrV), "FBString");
105
106   folly::StringPiece spV("StringPiece");
107   EXPECT_EQ(to<folly::StringPiece>(spV), "StringPiece");
108
109   // Rvalues
110   EXPECT_EQ(to<bool>(true), true);
111   EXPECT_EQ(to<int>(42), 42);
112   EXPECT_EQ(to<float>(4.2f), 4.2f);
113   EXPECT_EQ(to<double>(.42), .42);
114   EXPECT_EQ(to<std::string>(std::string("Hello")), "Hello");
115   EXPECT_EQ(to<folly::fbstring>(folly::fbstring("hello")), "hello");
116   EXPECT_EQ(to<folly::StringPiece>(folly::StringPiece("Forty Two")),
117             "Forty Two");
118 }
119
120 TEST(Conv, Integral2Integral) {
121   // Same size, different signs
122   int64_t s64 = numeric_limits<uint8_t>::max();
123   EXPECT_EQ(to<uint8_t>(s64), s64);
124
125   s64 = numeric_limits<int8_t>::max();
126   EXPECT_EQ(to<int8_t>(s64), s64);
127 }
128
129 TEST(Conv, Floating2Floating) {
130   float f1 = 1e3f;
131   double d1 = to<double>(f1);
132   EXPECT_EQ(f1, d1);
133
134   double d2 = 23.0;
135   auto f2 = to<float>(d2);
136   EXPECT_EQ(double(f2), d2);
137
138   double invalidFloat = std::numeric_limits<double>::max();
139   EXPECT_ANY_THROW(to<float>(invalidFloat));
140   invalidFloat = -std::numeric_limits<double>::max();
141   EXPECT_ANY_THROW(to<float>(invalidFloat));
142
143   try {
144     auto shouldWork = to<float>(std::numeric_limits<double>::min());
145     // The value of `shouldWork' is an implementation defined choice
146     // between the following two alternatives.
147     EXPECT_TRUE(shouldWork == std::numeric_limits<float>::min() ||
148                 shouldWork == 0.f);
149   } catch (...) {
150     ADD_FAILURE();
151   }
152 }
153
154 template <class String>
155 void testIntegral2String() {
156 }
157
158 template <class String, class Int, class... Ints>
159 void testIntegral2String() {
160   typedef typename make_unsigned<Int>::type Uint;
161   typedef typename make_signed<Int>::type Sint;
162
163   Uint value = 123;
164   EXPECT_EQ(to<String>(value), "123");
165   Sint svalue = 123;
166   EXPECT_EQ(to<String>(svalue), "123");
167   svalue = -123;
168   EXPECT_EQ(to<String>(svalue), "-123");
169
170   value = numeric_limits<Uint>::min();
171   EXPECT_EQ(to<Uint>(to<String>(value)), value);
172   value = numeric_limits<Uint>::max();
173   EXPECT_EQ(to<Uint>(to<String>(value)), value);
174
175   svalue = numeric_limits<Sint>::min();
176   EXPECT_EQ(to<Sint>(to<String>(svalue)), svalue);
177   value = numeric_limits<Sint>::max();
178   EXPECT_EQ(to<Sint>(to<String>(svalue)), svalue);
179
180   testIntegral2String<String, Ints...>();
181 }
182
183 #if FOLLY_HAVE_INT128_T
184 template <class String>
185 void test128Bit2String() {
186   typedef unsigned __int128 Uint;
187   typedef __int128 Sint;
188
189   EXPECT_EQ(detail::digitsEnough<unsigned __int128>(), 39);
190
191   Uint value = 123;
192   EXPECT_EQ(to<String>(value), "123");
193   Sint svalue = 123;
194   EXPECT_EQ(to<String>(svalue), "123");
195   svalue = -123;
196   EXPECT_EQ(to<String>(svalue), "-123");
197
198   value = __int128(1) << 64;
199   EXPECT_EQ(to<String>(value), "18446744073709551616");
200
201   svalue =  -(__int128(1) << 64);
202   EXPECT_EQ(to<String>(svalue), "-18446744073709551616");
203
204   value = 0;
205   EXPECT_EQ(to<String>(value), "0");
206
207   svalue = 0;
208   EXPECT_EQ(to<String>(svalue), "0");
209
210   value = ~__int128(0);
211   EXPECT_EQ(to<String>(value), "340282366920938463463374607431768211455");
212
213   svalue = -(Uint(1) << 127);
214   EXPECT_EQ(to<String>(svalue), "-170141183460469231731687303715884105728");
215
216   svalue = (Uint(1) << 127) - 1;
217   EXPECT_EQ(to<String>(svalue), "170141183460469231731687303715884105727");
218
219   // TODO: the following do not compile to<__int128> ...
220
221 #if 0
222   value = numeric_limits<Uint>::min();
223   EXPECT_EQ(to<Uint>(to<String>(value)), value);
224   value = numeric_limits<Uint>::max();
225   EXPECT_EQ(to<Uint>(to<String>(value)), value);
226
227   svalue = numeric_limits<Sint>::min();
228   EXPECT_EQ(to<Sint>(to<String>(svalue)), svalue);
229   value = numeric_limits<Sint>::max();
230   EXPECT_EQ(to<Sint>(to<String>(svalue)), svalue);
231 #endif
232 }
233
234 #endif
235
236 TEST(Conv, Integral2String) {
237   testIntegral2String<std::string, int8_t, int16_t, int32_t, int64_t>();
238   testIntegral2String<fbstring, int8_t, int16_t, int32_t, int64_t>();
239
240 #if FOLLY_HAVE_INT128_T
241   test128Bit2String<std::string>();
242   test128Bit2String<fbstring>();
243 #endif
244 }
245
246 template <class String>
247 void testString2Integral() {
248 }
249
250 template <class String, class Int, class... Ints>
251 void testString2Integral() {
252   typedef typename make_unsigned<Int>::type Uint;
253   typedef typename make_signed<Int>::type Sint;
254
255   // Unsigned numbers small enough to fit in a signed type
256   static const String strings[] = {
257     "0",
258     "00",
259     "2 ",
260     " 84",
261     " \n 123    \t\n",
262     " 127",
263     "0000000000000000000000000042"
264   };
265   static const Uint values[] = {
266     0,
267     0,
268     2,
269     84,
270     123,
271     127,
272     42
273   };
274   FOR_EACH_RANGE (i, 0, sizeof(strings) / sizeof(*strings)) {
275     EXPECT_EQ(to<Uint>(strings[i]), values[i]);
276     EXPECT_EQ(to<Sint>(strings[i]), values[i]);
277   }
278
279   // Unsigned numbers that won't fit in the signed variation
280   static const String uStrings[] = {
281     " 128",
282     "213",
283     "255"
284   };
285   static const Uint uValues[] = {
286     128,
287     213,
288     255
289   };
290   FOR_EACH_RANGE (i, 0, sizeof(uStrings)/sizeof(*uStrings)) {
291     EXPECT_EQ(to<Uint>(uStrings[i]), uValues[i]);
292     if (sizeof(Int) == 1) {
293       EXPECT_THROW(to<Sint>(uStrings[i]), std::range_error);
294     }
295   }
296
297   if (sizeof(Int) >= 4) {
298     static const String strings2[] = {
299       "256",
300       "6324 ",
301       "63245675 ",
302       "2147483647"
303     };
304     static const Uint values2[] = {
305       (Uint)256,
306       (Uint)6324,
307       (Uint)63245675,
308       (Uint)2147483647
309     };
310     FOR_EACH_RANGE (i, 0, sizeof(strings2)/sizeof(*strings2)) {
311       EXPECT_EQ(to<Uint>(strings2[i]), values2[i]);
312       EXPECT_EQ(to<Sint>(strings2[i]), values2[i]);
313     }
314
315     static const String uStrings2[] = {
316       "2147483648",
317       "3147483648",
318       "4147483648",
319       "4000000000",
320     };
321     static const Uint uValues2[] = {
322       (Uint)2147483648U,
323       (Uint)3147483648U,
324       (Uint)4147483648U,
325       (Uint)4000000000U,
326     };
327     FOR_EACH_RANGE (i, 0, sizeof(uStrings2)/sizeof(uStrings2)) {
328       EXPECT_EQ(to<Uint>(uStrings2[i]), uValues2[i]);
329       if (sizeof(Int) == 4) {
330         EXPECT_THROW(to<Sint>(uStrings2[i]), std::range_error);
331       }
332     }
333   }
334
335   if (sizeof(Int) >= 8) {
336     static_assert(sizeof(Int) <= 8, "Now that would be interesting");
337     static const String strings3[] = {
338       "2147483648",
339       "5000000001",
340       "25687346509278435",
341       "100000000000000000",
342       "9223372036854775807",
343     };
344     static const Uint values3[] = {
345       (Uint)2147483648ULL,
346       (Uint)5000000001ULL,
347       (Uint)25687346509278435ULL,
348       (Uint)100000000000000000ULL,
349       (Uint)9223372036854775807ULL,
350     };
351     FOR_EACH_RANGE (i, 0, sizeof(strings3)/sizeof(*strings3)) {
352       EXPECT_EQ(to<Uint>(strings3[i]), values3[i]);
353       EXPECT_EQ(to<Sint>(strings3[i]), values3[i]);
354     }
355
356     static const String uStrings3[] = {
357       "9223372036854775808",
358       "9987435987394857987",
359       "17873648761234698740",
360       "18446744073709551615",
361     };
362     static const Uint uValues3[] = {
363       (Uint)9223372036854775808ULL,
364       (Uint)9987435987394857987ULL,
365       (Uint)17873648761234698740ULL,
366       (Uint)18446744073709551615ULL,
367     };
368     FOR_EACH_RANGE (i, 0, sizeof(uStrings3)/sizeof(*uStrings3)) {
369       EXPECT_EQ(to<Uint>(uStrings3[i]), uValues3[i]);
370       if (sizeof(Int) == 8) {
371         EXPECT_THROW(to<Sint>(uStrings3[i]), std::range_error);
372       }
373     }
374   }
375
376   // Minimum possible negative values, and negative sign overflow
377   static const String strings4[] = {
378     "-128",
379     "-32768",
380     "-2147483648",
381     "-9223372036854775808",
382   };
383   static const String strings5[] = {
384     "-129",
385     "-32769",
386     "-2147483649",
387     "-9223372036854775809",
388   };
389   static const Sint values4[] = {
390     (Sint)-128LL,
391     (Sint)-32768LL,
392     (Sint)-2147483648LL,
393     (Sint)(-9223372036854775807LL - 1),
394   };
395   FOR_EACH_RANGE (i, 0, sizeof(strings4)/sizeof(*strings4)) {
396     if (sizeof(Int) > std::pow(2, i)) {
397       EXPECT_EQ(values4[i], to<Sint>(strings4[i]));
398       EXPECT_EQ(values4[i] - 1, to<Sint>(strings5[i]));
399     } else if (sizeof(Int) == std::pow(2, i)) {
400       EXPECT_EQ(values4[i], to<Sint>(strings4[i]));
401       EXPECT_THROW(to<Sint>(strings5[i]), std::range_error);
402     } else {
403       EXPECT_THROW(to<Sint>(strings4[i]), std::range_error);
404       EXPECT_THROW(to<Sint>(strings5[i]), std::range_error);
405     }
406   }
407
408   // Bogus string values
409   static const String bogusStrings[] = {
410     "",
411     "0x1234",
412     "123L",
413     "123a",
414     "x 123 ",
415     "234 y",
416     "- 42",  // whitespace is not allowed between the sign and the value
417     " +   13 ",
418     "12345678901234567890123456789",
419   };
420   for (const auto& str : bogusStrings) {
421     EXPECT_THROW(to<Sint>(str), std::range_error);
422     EXPECT_THROW(to<Uint>(str), std::range_error);
423   }
424
425   // A leading '+' character is only allowed when converting to signed types.
426   String posSign("+42");
427   EXPECT_EQ(42, to<Sint>(posSign));
428   EXPECT_THROW(to<Uint>(posSign), std::range_error);
429
430   testString2Integral<String, Ints...>();
431 }
432
433 TEST(Conv, String2Integral) {
434   testString2Integral<const char*, int8_t, int16_t, int32_t, int64_t>();
435   testString2Integral<std::string, int8_t, int16_t, int32_t, int64_t>();
436   testString2Integral<fbstring, int8_t, int16_t, int32_t, int64_t>();
437
438   // Testing the behavior of the StringPiece* API
439   // StringPiece* normally parses as much valid data as it can,
440   // and advances the StringPiece to the end of the valid data.
441   char buf1[] = "100foo";
442   StringPiece sp1(buf1);
443   EXPECT_EQ(100, to<uint8_t>(&sp1));
444   EXPECT_EQ(buf1 + 3, sp1.begin());
445   // However, if the next character would cause an overflow it throws a
446   // range_error rather than consuming only as much as it can without
447   // overflowing.
448   char buf2[] = "1002";
449   StringPiece sp2(buf2);
450   EXPECT_THROW(to<uint8_t>(&sp2), std::range_error);
451   EXPECT_EQ(buf2, sp2.begin());
452 }
453
454 TEST(Conv, StringPiece2Integral) {
455   string s = "  +123  hello world  ";
456   StringPiece sp = s;
457   EXPECT_EQ(to<int>(&sp), 123);
458   EXPECT_EQ(sp, "  hello world  ");
459 }
460
461 TEST(Conv, StringPieceAppend) {
462   string s = "foobar";
463   {
464     StringPiece sp(s, 0, 3);
465     string result = to<string>(s, sp);
466     EXPECT_EQ(result, "foobarfoo");
467   }
468   {
469     StringPiece sp1(s, 0, 3);
470     StringPiece sp2(s, 3, 3);
471     string result = to<string>(sp1, sp2);
472     EXPECT_EQ(result, s);
473   }
474 }
475
476 TEST(Conv, BadStringToIntegral) {
477   // Note that leading spaces (e.g.  " 1") are valid.
478   vector<string> v = { "a", "", " ", "\n", " a0", "abcdef", "1Z", "!#" };
479   for (auto& s: v) {
480     EXPECT_THROW(to<int>(s), std::range_error) << "s=" << s;
481   }
482 }
483
484 template <class String>
485 void testIdenticalTo() {
486   String s("Yukkuri shiteitte ne!!!");
487
488   String result = to<String>(s);
489   EXPECT_EQ(result, s);
490 }
491
492 template <class String>
493 void testVariadicTo() {
494   String s;
495   toAppend(&s);
496   toAppend("Lorem ipsum ", 1234, String(" dolor amet "), 567.89, '!', &s);
497   EXPECT_EQ(s, "Lorem ipsum 1234 dolor amet 567.89!");
498
499   s = to<String>();
500   EXPECT_TRUE(s.empty());
501
502   s = to<String>("Lorem ipsum ", nullptr, 1234, " dolor amet ", 567.89, '.');
503   EXPECT_EQ(s, "Lorem ipsum 1234 dolor amet 567.89.");
504 }
505
506 template <class String>
507 void testIdenticalToDelim() {
508   String s("Yukkuri shiteitte ne!!!");
509
510   String charDelim = toDelim<String>('$', s);
511   EXPECT_EQ(charDelim, s);
512
513   String strDelim = toDelim<String>(String(">_<"), s);
514   EXPECT_EQ(strDelim, s);
515 }
516
517 template <class String>
518 void testVariadicToDelim() {
519   String s;
520   toAppendDelim(":", &s);
521   toAppendDelim(
522       ":", "Lorem ipsum ", 1234, String(" dolor amet "), 567.89, '!', &s);
523   EXPECT_EQ(s, "Lorem ipsum :1234: dolor amet :567.89:!");
524
525   s = toDelim<String>(':');
526   EXPECT_TRUE(s.empty());
527
528   s = toDelim<String>(
529       ":", "Lorem ipsum ", nullptr, 1234, " dolor amet ", 567.89, '.');
530   EXPECT_EQ(s, "Lorem ipsum ::1234: dolor amet :567.89:.");
531 }
532
533 TEST(Conv, NullString) {
534   string s1 = to<string>((char *) nullptr);
535   EXPECT_TRUE(s1.empty());
536   fbstring s2 = to<fbstring>((char *) nullptr);
537   EXPECT_TRUE(s2.empty());
538 }
539
540 TEST(Conv, VariadicTo) {
541   testIdenticalTo<string>();
542   testIdenticalTo<fbstring>();
543   testVariadicTo<string>();
544   testVariadicTo<fbstring>();
545 }
546
547 TEST(Conv, VariadicToDelim) {
548   testIdenticalToDelim<string>();
549   testIdenticalToDelim<fbstring>();
550   testVariadicToDelim<string>();
551   testVariadicToDelim<fbstring>();
552 }
553
554 template <class String>
555 void testDoubleToString() {
556   EXPECT_EQ(to<string>(0.0), "0");
557   EXPECT_EQ(to<string>(0.5), "0.5");
558   EXPECT_EQ(to<string>(10.25), "10.25");
559   EXPECT_EQ(to<string>(1.123e10), "11230000000");
560 }
561
562 TEST(Conv, DoubleToString) {
563   testDoubleToString<string>();
564   testDoubleToString<fbstring>();
565 }
566
567 TEST(Conv, FBStringToString) {
568   fbstring foo("foo");
569   string ret = to<string>(foo);
570   EXPECT_EQ(ret, "foo");
571   string ret2 = to<string>(foo, 2);
572   EXPECT_EQ(ret2, "foo2");
573 }
574
575 TEST(Conv, StringPieceToDouble) {
576   vector<tuple<const char*, const char*, double>> strs{
577       make_tuple("2134123.125 zorro", " zorro", 2134123.125),
578       make_tuple("  2134123.125 zorro", " zorro", 2134123.125),
579       make_tuple(" 2134123.125  zorro", "  zorro", 2134123.125),
580       make_tuple(" 2134123.125  zorro ", "  zorro ", 2134123.125),
581       make_tuple("2134123.125zorro", "zorro", 2134123.125),
582       make_tuple("0 zorro", " zorro", 0.0),
583       make_tuple("  0 zorro", " zorro", 0.0),
584       make_tuple(" 0  zorro", "  zorro", 0.0),
585       make_tuple(" 0  zorro ", "  zorro ", 0.0),
586       make_tuple("0zorro", "zorro", 0.0),
587       make_tuple("0.0 zorro", " zorro", 0.0),
588       make_tuple("  0.0 zorro", " zorro", 0.0),
589       make_tuple(" 0.0  zorro", "  zorro", 0.0),
590       make_tuple(" 0.0  zorro ", "  zorro ", 0.0),
591       make_tuple("0.0zorro", "zorro", 0.0),
592   };
593   for (const auto& s : strs) {
594     StringPiece pc(get<0>(s));
595     EXPECT_EQ(get<2>(s), to<double>(&pc)) << "\"" << get<0>(s) << "\"";
596     EXPECT_EQ(get<1>(s), pc);
597     EXPECT_THROW(to<double>(StringPiece(get<0>(s))), std::range_error);
598     EXPECT_EQ(get<2>(s), to<double>(StringPiece(get<0>(s), pc.data())));
599   }
600
601   // Test NaN conversion
602   try {
603     to<double>("not a number");
604     ADD_FAILURE();
605   } catch (const std::range_error &) {
606   }
607
608   EXPECT_TRUE(std::isnan(to<double>("nan")));
609   EXPECT_TRUE(std::isnan(to<double>("NaN")));
610   EXPECT_TRUE(std::isnan(to<double>("NAN")));
611   EXPECT_TRUE(std::isnan(to<double>("-nan")));
612   EXPECT_TRUE(std::isnan(to<double>("-NaN")));
613   EXPECT_TRUE(std::isnan(to<double>("-NAN")));
614
615   EXPECT_EQ(to<double>("inf"), numeric_limits<double>::infinity());
616   EXPECT_EQ(to<double>("Inf"), numeric_limits<double>::infinity());
617   EXPECT_EQ(to<double>("INF"), numeric_limits<double>::infinity());
618   EXPECT_EQ(to<double>("inF"), numeric_limits<double>::infinity());
619   EXPECT_EQ(to<double>("infinity"), numeric_limits<double>::infinity());
620   EXPECT_EQ(to<double>("Infinity"), numeric_limits<double>::infinity());
621   EXPECT_EQ(to<double>("INFINITY"), numeric_limits<double>::infinity());
622   EXPECT_EQ(to<double>("iNfInItY"), numeric_limits<double>::infinity());
623   EXPECT_THROW(to<double>("infinitX"), std::range_error);
624   EXPECT_EQ(to<double>("-inf"), -numeric_limits<double>::infinity());
625   EXPECT_EQ(to<double>("-Inf"), -numeric_limits<double>::infinity());
626   EXPECT_EQ(to<double>("-INF"), -numeric_limits<double>::infinity());
627   EXPECT_EQ(to<double>("-inF"), -numeric_limits<double>::infinity());
628   EXPECT_EQ(to<double>("-infinity"), -numeric_limits<double>::infinity());
629   EXPECT_EQ(to<double>("-Infinity"), -numeric_limits<double>::infinity());
630   EXPECT_EQ(to<double>("-INFINITY"), -numeric_limits<double>::infinity());
631   EXPECT_EQ(to<double>("-iNfInItY"), -numeric_limits<double>::infinity());
632   EXPECT_THROW(to<double>("-infinitX"), std::range_error);
633 }
634
635 TEST(Conv, EmptyStringToInt) {
636   string s = "";
637   StringPiece pc(s);
638
639   try {
640     to<int>(pc);
641     ADD_FAILURE();
642   } catch (const std::range_error &) {
643   }
644 }
645
646 TEST(Conv, CorruptedStringToInt) {
647   string s = "-1";
648   StringPiece pc(s.data(), s.data() + 1); // Only  "-"
649
650   try {
651     to<int64_t>(&pc);
652     ADD_FAILURE();
653   } catch (const std::range_error &) {
654   }
655 }
656
657 TEST(Conv, EmptyStringToDouble) {
658   string s = "";
659   StringPiece pc(s);
660
661   try {
662     to<double>(pc);
663     ADD_FAILURE();
664   } catch (const std::range_error &) {
665   }
666 }
667
668 TEST(Conv, IntToDouble) {
669   auto d = to<double>(42);
670   EXPECT_EQ(d, 42);
671   /* This seems not work in ubuntu11.10, gcc 4.6.1
672   try {
673     auto f = to<float>(957837589847);
674     ADD_FAILURE();
675   } catch (std::range_error& e) {
676     //LOG(INFO) << e.what();
677   }
678   */
679 }
680
681 TEST(Conv, DoubleToInt) {
682   auto i = to<int>(42.0);
683   EXPECT_EQ(i, 42);
684   try {
685     auto i2 = to<int>(42.1);
686     LOG(ERROR) << "to<int> returned " << i2 << " instead of throwing";
687     ADD_FAILURE();
688   } catch (std::range_error&) {
689     //LOG(INFO) << e.what();
690   }
691 }
692
693 TEST(Conv, EnumToInt) {
694   enum A { x = 42, y = 420, z = 65 };
695   auto i = to<int>(x);
696   EXPECT_EQ(i, 42);
697   auto j = to<char>(x);
698   EXPECT_EQ(j, 42);
699   try {
700     auto i2 = to<char>(y);
701     LOG(ERROR) << "to<char> returned "
702                << static_cast<unsigned int>(i2)
703                << " instead of throwing";
704     ADD_FAILURE();
705   } catch (std::range_error&) {
706     //LOG(INFO) << e.what();
707   }
708 }
709
710 TEST(Conv, EnumToString) {
711   // task 813959
712   enum A { x = 4, y = 420, z = 65 };
713   EXPECT_EQ("foo.4", to<string>("foo.", x));
714   EXPECT_EQ("foo.420", to<string>("foo.", y));
715   EXPECT_EQ("foo.65", to<string>("foo.", z));
716 }
717
718 TEST(Conv, IntToEnum) {
719   enum A { x = 42, y = 420 };
720   auto i = to<A>(42);
721   EXPECT_EQ(i, x);
722   auto j = to<A>(100);
723   EXPECT_EQ(j, 100);
724   try {
725     auto i2 = to<A>(5000000000L);
726     LOG(ERROR) << "to<A> returned "
727                << static_cast<unsigned int>(i2)
728                << " instead of throwing";
729     ADD_FAILURE();
730   } catch (std::range_error&) {
731     //LOG(INFO) << e.what();
732   }
733 }
734
735 TEST(Conv, UnsignedEnum) {
736   enum E : uint32_t { x = 3000000000U };
737   auto u = to<uint32_t>(x);
738   EXPECT_EQ(u, 3000000000U);
739   auto s = to<string>(x);
740   EXPECT_EQ("3000000000", s);
741   auto e = to<E>(3000000000U);
742   EXPECT_EQ(e, x);
743   try {
744     auto i = to<int32_t>(x);
745     LOG(ERROR) << "to<int32_t> returned " << i << " instead of throwing";
746     ADD_FAILURE();
747   } catch (std::range_error&) {
748   }
749 }
750
751 TEST(Conv, UnsignedEnumClass) {
752   enum class E : uint32_t { x = 3000000000U };
753   auto u = to<uint32_t>(E::x);
754   EXPECT_GT(u, 0);
755   EXPECT_EQ(u, 3000000000U);
756   EXPECT_EQ("3000000000", to<string>(E::x));
757   EXPECT_EQ(E::x, to<E>(3000000000U));
758   EXPECT_EQ(E::x, to<E>("3000000000"));
759   E e;
760   EXPECT_TRUE(parseTo("3000000000", e).hasValue());
761   EXPECT_EQ(E::x, e);
762   EXPECT_THROW(to<int32_t>(E::x), std::range_error);
763 }
764
765 // Multi-argument to<string> uses toAppend, a different code path than
766 // to<string>(enum).
767 TEST(Conv, EnumClassToString) {
768   enum class A { x = 4, y = 420, z = 65 };
769   EXPECT_EQ("foo.4", to<string>("foo.", A::x));
770   EXPECT_EQ("foo.420", to<string>("foo.", A::y));
771   EXPECT_EQ("foo.65", to<string>("foo.", A::z));
772 }
773
774 TEST(Conv, IntegralToBool) {
775   EXPECT_FALSE(to<bool>(0));
776   EXPECT_FALSE(to<bool>(0ul));
777
778   EXPECT_TRUE(to<bool>(1));
779   EXPECT_TRUE(to<bool>(1ul));
780
781   EXPECT_TRUE(to<bool>(-42));
782   EXPECT_TRUE(to<bool>(42ul));
783 }
784
785 template <typename Src>
786 void testStr2Bool() {
787   EXPECT_FALSE(to<bool>(Src("0")));
788   EXPECT_FALSE(to<bool>(Src("  000  ")));
789
790   EXPECT_FALSE(to<bool>(Src("n")));
791   EXPECT_FALSE(to<bool>(Src("no")));
792   EXPECT_FALSE(to<bool>(Src("false")));
793   EXPECT_FALSE(to<bool>(Src("False")));
794   EXPECT_FALSE(to<bool>(Src("  fAlSe"  )));
795   EXPECT_FALSE(to<bool>(Src("F")));
796   EXPECT_FALSE(to<bool>(Src("off")));
797
798   EXPECT_TRUE(to<bool>(Src("1")));
799   EXPECT_TRUE(to<bool>(Src("  001 ")));
800   EXPECT_TRUE(to<bool>(Src("y")));
801   EXPECT_TRUE(to<bool>(Src("yes")));
802   EXPECT_TRUE(to<bool>(Src("\nyEs\t")));
803   EXPECT_TRUE(to<bool>(Src("true")));
804   EXPECT_TRUE(to<bool>(Src("True")));
805   EXPECT_TRUE(to<bool>(Src("T")));
806   EXPECT_TRUE(to<bool>(Src("on")));
807
808   EXPECT_THROW(to<bool>(Src("")), std::range_error);
809   EXPECT_THROW(to<bool>(Src("2")), std::range_error);
810   EXPECT_THROW(to<bool>(Src("11")), std::range_error);
811   EXPECT_THROW(to<bool>(Src("19")), std::range_error);
812   EXPECT_THROW(to<bool>(Src("o")), std::range_error);
813   EXPECT_THROW(to<bool>(Src("fal")), std::range_error);
814   EXPECT_THROW(to<bool>(Src("tru")), std::range_error);
815   EXPECT_THROW(to<bool>(Src("ye")), std::range_error);
816   EXPECT_THROW(to<bool>(Src("yes foo")), std::range_error);
817   EXPECT_THROW(to<bool>(Src("bar no")), std::range_error);
818   EXPECT_THROW(to<bool>(Src("one")), std::range_error);
819   EXPECT_THROW(to<bool>(Src("true_")), std::range_error);
820   EXPECT_THROW(to<bool>(Src("bogus_token_that_is_too_long")),
821                std::range_error);
822 }
823
824 TEST(Conv, StringToBool) {
825   // testStr2Bool<const char *>();
826   testStr2Bool<std::string>();
827
828   // Test with strings that are not NUL terminated.
829   const char buf[] = "01234";
830   EXPECT_FALSE(to<bool>(StringPiece(buf, buf + 1)));  // "0"
831   EXPECT_TRUE(to<bool>(StringPiece(buf + 1, buf + 2)));  // "1"
832   const char buf2[] = "one two three";
833   EXPECT_TRUE(to<bool>(StringPiece(buf2, buf2 + 2)));  // "on"
834   const char buf3[] = "false";
835   EXPECT_THROW(to<bool>(StringPiece(buf3, buf3 + 3)),  // "fal"
836                std::range_error);
837
838   // Test the StringPiece* API
839   const char buf4[] = "001foo";
840   StringPiece sp4(buf4);
841   EXPECT_TRUE(to<bool>(&sp4));
842   EXPECT_EQ(buf4 + 3, sp4.begin());
843   const char buf5[] = "0012";
844   StringPiece sp5(buf5);
845   EXPECT_THROW(to<bool>(&sp5), std::range_error);
846   EXPECT_EQ(buf5, sp5.begin());
847 }
848
849 TEST(Conv, Transform) {
850   const std::vector<int64_t> in{1, 2, 3};
851   std::vector<std::string> out(in.size());
852   std::transform(in.begin(), in.end(), out.begin(), to<std::string, int64_t>);
853   const std::vector<std::string> ref{"1", "2", "3"};
854   EXPECT_EQ(ref, out);
855 }
856
857 TEST(Conv, FloatToInt) {
858   EXPECT_EQ(to<int>(42.0f), 42);
859   EXPECT_EQ(to<int8_t>(-128.0f), int8_t(-128));
860   EXPECT_THROW(to<int8_t>(-129.0), std::range_error);
861   EXPECT_THROW(to<int8_t>(127.001), std::range_error);
862   EXPECT_THROW(to<uint8_t>(-0.0001), std::range_error);
863   EXPECT_THROW(
864       to<uint64_t>(static_cast<float>(std::numeric_limits<uint64_t>::max())),
865       std::range_error);
866 }
867
868 TEST(Conv, IntToFloat) {
869   EXPECT_EQ(to<float>(42ULL), 42.0);
870   EXPECT_EQ(to<float>(int8_t(-128)), -128.0);
871   EXPECT_THROW(
872       to<float>(std::numeric_limits<uint64_t>::max()), std::range_error);
873   EXPECT_THROW(
874       to<float>(std::numeric_limits<int64_t>::max()), std::range_error);
875   EXPECT_THROW(
876       to<float>(std::numeric_limits<int64_t>::min() + 1), std::range_error);
877 #if FOLLY_HAVE_INT128_T
878   EXPECT_THROW(
879       to<double>(std::numeric_limits<unsigned __int128>::max()),
880       std::range_error);
881   EXPECT_THROW(
882       to<double>(std::numeric_limits<__int128>::max()), std::range_error);
883   EXPECT_THROW(
884       to<double>(std::numeric_limits<__int128>::min() + 1), std::range_error);
885 #endif
886 }
887
888 TEST(Conv, BoolToFloat) {
889   EXPECT_EQ(to<double>(true), 1.0);
890   EXPECT_EQ(to<double>(false), 0.0);
891 }
892
893 TEST(Conv, FloatToBool) {
894   EXPECT_EQ(to<bool>(1.0), true);
895   EXPECT_EQ(to<bool>(0.0), false);
896   EXPECT_EQ(to<bool>(2.7), true);
897   EXPECT_EQ(to<bool>(std::numeric_limits<double>::max()), true);
898   EXPECT_EQ(to<bool>(std::numeric_limits<double>::min()), true);
899   EXPECT_EQ(to<bool>(std::numeric_limits<double>::lowest()), true);
900   EXPECT_EQ(to<bool>(std::numeric_limits<double>::quiet_NaN()), true);
901   EXPECT_EQ(to<bool>(std::numeric_limits<double>::infinity()), true);
902   EXPECT_EQ(to<bool>(-std::numeric_limits<double>::infinity()), true);
903 }
904
905 namespace {
906
907 template <typename F>
908 void testConvError(
909     F&& expr,
910     const char* exprStr,
911     ConversionCode code,
912     const char* value,
913     bool quotedValue,
914     int line) {
915   std::string where = to<std::string>(__FILE__, "(", line, "): ");
916   try {
917     auto res = expr();
918     ADD_FAILURE() << where << exprStr << " -> " << res;
919   } catch (const ConversionError& e) {
920     EXPECT_EQ(code, e.errorCode()) << where << exprStr;
921     std::string str(e.what());
922     EXPECT_FALSE(str.empty()) << where << exprStr << " -> " << str;
923     auto pos = str.find(':');
924     if (value) {
925       std::ostringstream exp;
926       exp << str.substr(0, pos) + ": ";
927       if (quotedValue) {
928         exp << "\"" << value << "\"";
929       } else {
930         exp << value;
931       }
932       EXPECT_EQ(exp.str(), str) << where << exprStr << " -> " << str;
933     } else {
934       EXPECT_EQ(pos, std::string::npos) << where << exprStr << " -> " << str;
935     }
936   }
937 }
938 }
939
940 #define EXPECT_CONV_ERROR_QUOTE(expr, code, value, quoted) \
941   testConvError(                                           \
942       [&] { return expr; },                                \
943       #expr,                                               \
944       ConversionCode::code,                                \
945       value,                                               \
946       quoted,                                              \
947       __LINE__)
948
949 #define EXPECT_CONV_ERROR(expr, code, value) \
950   EXPECT_CONV_ERROR_QUOTE(expr, code, value, true)
951
952 #define EXPECT_CONV_ERROR_STR(type, str, code) \
953   EXPECT_CONV_ERROR(to<type>(str), code, str)
954
955 #define EXPECT_CONV_ERROR_STR_NOVAL(type, str, code) \
956   EXPECT_CONV_ERROR(to<type>(str), code, nullptr)
957
958 TEST(Conv, ConversionErrorStrToBool) {
959   EXPECT_CONV_ERROR_STR_NOVAL(bool, StringPiece(), EMPTY_INPUT_STRING);
960   EXPECT_CONV_ERROR_STR_NOVAL(bool, "", EMPTY_INPUT_STRING);
961   EXPECT_CONV_ERROR_STR(bool, "  ", EMPTY_INPUT_STRING);
962   EXPECT_CONV_ERROR_STR(bool, " 11 ", BOOL_OVERFLOW);
963   EXPECT_CONV_ERROR_STR(bool, "other ", BOOL_INVALID_VALUE);
964   EXPECT_CONV_ERROR_STR(bool, " bla", BOOL_INVALID_VALUE);
965   EXPECT_CONV_ERROR(to<bool>("  offbla"), NON_WHITESPACE_AFTER_END, "bla");
966 }
967
968 TEST(Conv, ConversionErrorStrToFloat) {
969   EXPECT_CONV_ERROR_STR_NOVAL(float, StringPiece(), EMPTY_INPUT_STRING);
970   EXPECT_CONV_ERROR_STR_NOVAL(float, "", EMPTY_INPUT_STRING);
971   EXPECT_CONV_ERROR_STR(float, "  ", EMPTY_INPUT_STRING);
972   EXPECT_CONV_ERROR_STR(float, "  junk", STRING_TO_FLOAT_ERROR);
973   EXPECT_CONV_ERROR(to<float>("  1bla"), NON_WHITESPACE_AFTER_END, "bla");
974 }
975
976 TEST(Conv, ConversionErrorStrToInt) {
977   // empty string handling
978   EXPECT_CONV_ERROR_STR_NOVAL(int, StringPiece(), EMPTY_INPUT_STRING);
979   EXPECT_CONV_ERROR_STR_NOVAL(int, "", EMPTY_INPUT_STRING);
980   EXPECT_CONV_ERROR_STR(int, "  ", EMPTY_INPUT_STRING);
981
982   // signed integers
983   EXPECT_CONV_ERROR_STR(int, "  *", INVALID_LEADING_CHAR);
984   EXPECT_CONV_ERROR_STR(int, "  +", NO_DIGITS);
985   EXPECT_CONV_ERROR_STR(int, "  +*", NON_DIGIT_CHAR);
986   EXPECT_CONV_ERROR_STR(int8_t, "  128", POSITIVE_OVERFLOW);
987   EXPECT_CONV_ERROR_STR(int8_t, " -129", NEGATIVE_OVERFLOW);
988   EXPECT_CONV_ERROR_STR(int8_t, " 1000", POSITIVE_OVERFLOW);
989   EXPECT_CONV_ERROR_STR(int8_t, "-1000", NEGATIVE_OVERFLOW);
990   EXPECT_CONV_ERROR(to<int>(" -13bla"), NON_WHITESPACE_AFTER_END, "bla");
991
992   // unsigned integers
993   EXPECT_CONV_ERROR_STR(unsigned, "  -", NON_DIGIT_CHAR);
994   EXPECT_CONV_ERROR_STR(uint8_t, " 256", POSITIVE_OVERFLOW);
995   EXPECT_CONV_ERROR(to<unsigned>("42bla"), NON_WHITESPACE_AFTER_END, "bla");
996 }
997
998 #define EXPECT_CONV_ERROR_PP_VAL(type, str, code, val)                  \
999   do {                                                                  \
1000     StringPiece input(str);                                             \
1001     EXPECT_CONV_ERROR(to<type>(input.begin(), input.end()), code, val); \
1002   } while (0)
1003
1004 #define EXPECT_CONV_ERROR_PP(type, str, code) \
1005   EXPECT_CONV_ERROR_PP_VAL(type, str, code, str)
1006
1007 TEST(Conv, ConversionErrorPtrPairToInt) {
1008   // signed integers
1009   EXPECT_CONV_ERROR_PP(int, "", INVALID_LEADING_CHAR);
1010   EXPECT_CONV_ERROR_PP(int, " ", INVALID_LEADING_CHAR);
1011   EXPECT_CONV_ERROR_PP(int, "*", INVALID_LEADING_CHAR);
1012   EXPECT_CONV_ERROR_PP(int, "+", NO_DIGITS);
1013   EXPECT_CONV_ERROR_PP(int8_t, "128", POSITIVE_OVERFLOW);
1014   EXPECT_CONV_ERROR_PP(int8_t, "-129", NEGATIVE_OVERFLOW);
1015   EXPECT_CONV_ERROR_PP(int8_t, "1000", POSITIVE_OVERFLOW);
1016   EXPECT_CONV_ERROR_PP(int8_t, "-1000", NEGATIVE_OVERFLOW);
1017   EXPECT_CONV_ERROR_PP(int, "-junk", NON_DIGIT_CHAR);
1018
1019   // unsigned integers
1020   EXPECT_CONV_ERROR_PP(unsigned, "", NO_DIGITS);
1021   EXPECT_CONV_ERROR_PP(uint8_t, "256", POSITIVE_OVERFLOW);
1022   EXPECT_CONV_ERROR_PP(unsigned, "junk", NON_DIGIT_CHAR);
1023 }
1024
1025 namespace {
1026
1027 template <typename T, typename V>
1028 std::string prefixWithType(V value) {
1029   std::ostringstream oss;
1030 #ifdef FOLLY_HAS_RTTI
1031   oss << "(" << demangle(typeid(T)) << ") ";
1032 #endif
1033   oss << to<std::string>(value);
1034   return oss.str();
1035 }
1036 }
1037
1038 #define EXPECT_CONV_ERROR_ARITH(type, val, code) \
1039   EXPECT_CONV_ERROR_QUOTE(                       \
1040       to<type>(val), code, prefixWithType<type>(val).c_str(), false)
1041
1042 TEST(Conv, ConversionErrorIntToInt) {
1043   EXPECT_CONV_ERROR_ARITH(signed char, 128, ARITH_POSITIVE_OVERFLOW);
1044   EXPECT_CONV_ERROR_ARITH(unsigned char, -1, ARITH_NEGATIVE_OVERFLOW);
1045 }
1046
1047 TEST(Conv, ConversionErrorFloatToFloat) {
1048   EXPECT_CONV_ERROR_ARITH(
1049       float, std::numeric_limits<double>::max(), ARITH_POSITIVE_OVERFLOW);
1050   EXPECT_CONV_ERROR_ARITH(
1051       float, std::numeric_limits<double>::lowest(), ARITH_NEGATIVE_OVERFLOW);
1052 }
1053
1054 TEST(Conv, ConversionErrorIntToFloat) {
1055   EXPECT_CONV_ERROR_ARITH(
1056       float, std::numeric_limits<long long>::max(), ARITH_LOSS_OF_PRECISION);
1057 }
1058
1059 TEST(Conv, ConversionErrorFloatToInt) {
1060   EXPECT_CONV_ERROR_ARITH(int8_t, 65.5, ARITH_LOSS_OF_PRECISION);
1061 }
1062
1063 TEST(Conv, TryStringToBool) {
1064   auto rv1 = folly::tryTo<bool>("xxxx");
1065   EXPECT_FALSE(rv1.hasValue());
1066   auto rv2 = folly::tryTo<bool>("false");
1067   EXPECT_TRUE(rv2.hasValue());
1068   EXPECT_FALSE(rv2.value());
1069   auto rv3 = folly::tryTo<bool>("yes");
1070   EXPECT_TRUE(rv3.hasValue());
1071   EXPECT_TRUE(rv3.value());
1072 }
1073
1074 TEST(Conv, TryStringToInt) {
1075   auto rv1 = folly::tryTo<int>("1000000000000000000000000000000");
1076   EXPECT_FALSE(rv1.hasValue());
1077   auto rv2 = folly::tryTo<int>("4711");
1078   EXPECT_TRUE(rv2.hasValue());
1079   EXPECT_EQ(rv2.value(), 4711);
1080 }
1081
1082 TEST(Conv, TryStringToEnum) {
1083   enum class A { x = 42, y = 420, z = 65 };
1084   auto rv1 = folly::tryTo<A>("1000000000000000000000000000000");
1085   EXPECT_FALSE(rv1.hasValue());
1086   auto rv2 = folly::tryTo<A>("42");
1087   EXPECT_TRUE(rv2.hasValue());
1088   EXPECT_EQ(A::x, rv2.value());
1089   auto rv3 = folly::tryTo<A>("50");
1090   EXPECT_TRUE(rv3.hasValue());
1091   EXPECT_EQ(static_cast<A>(50), rv3.value());
1092 }
1093
1094 TEST(Conv, TryStringToFloat) {
1095   auto rv1 = folly::tryTo<float>("");
1096   EXPECT_FALSE(rv1.hasValue());
1097   auto rv2 = folly::tryTo<float>("3.14");
1098   EXPECT_TRUE(rv2.hasValue());
1099   EXPECT_NEAR(rv2.value(), 3.14, 1e-5);
1100 }
1101
1102 TEST(Conv, TryStringToDouble) {
1103   auto rv1 = folly::tryTo<double>("");
1104   EXPECT_FALSE(rv1.hasValue());
1105   auto rv2 = folly::tryTo<double>("3.14");
1106   EXPECT_TRUE(rv2.hasValue());
1107   EXPECT_NEAR(rv2.value(), 3.14, 1e-10);
1108 }
1109
1110 TEST(Conv, TryIntToInt) {
1111   auto rv1 = folly::tryTo<uint8_t>(256);
1112   EXPECT_FALSE(rv1.hasValue());
1113   auto rv2 = folly::tryTo<uint8_t>(255);
1114   EXPECT_TRUE(rv2.hasValue());
1115   EXPECT_EQ(rv2.value(), 255);
1116 }
1117
1118 TEST(Conv, TryFloatToFloat) {
1119   auto rv1 = folly::tryTo<float>(1e100);
1120   EXPECT_FALSE(rv1.hasValue());
1121   auto rv2 = folly::tryTo<double>(25.5f);
1122   EXPECT_TRUE(rv2.hasValue());
1123   EXPECT_NEAR(rv2.value(), 25.5, 1e-10);
1124 }
1125
1126 TEST(Conv, TryFloatToInt) {
1127   auto rv1 = folly::tryTo<int>(100.001);
1128   EXPECT_FALSE(rv1.hasValue());
1129   auto rv2 = folly::tryTo<int>(100.0);
1130   EXPECT_TRUE(rv2.hasValue());
1131   EXPECT_EQ(rv2.value(), 100);
1132 }
1133
1134 TEST(Conv, TryIntToFloat) {
1135   auto rv1 = folly::tryTo<float>(std::numeric_limits<uint64_t>::max());
1136   EXPECT_FALSE(rv1.hasValue());
1137   auto rv2 = folly::tryTo<float>(1000ULL);
1138   EXPECT_TRUE(rv2.hasValue());
1139   EXPECT_EQ(rv2.value(), 1000.0f);
1140 }
1141
1142 TEST(Conv, TryPtrPairToInt) {
1143   StringPiece sp1("1000000000000000000000000000000");
1144   auto rv1 = folly::tryTo<int>(sp1.begin(), sp1.end());
1145   EXPECT_FALSE(rv1.hasValue());
1146   StringPiece sp2("4711");
1147   auto rv2 = folly::tryTo<int>(sp2.begin(), sp2.end());
1148   EXPECT_TRUE(rv2.hasValue());
1149   EXPECT_EQ(rv2.value(), 4711);
1150   StringPiece sp3("-4711");
1151   auto rv3 = folly::tryTo<int>(sp3.begin(), sp3.end());
1152   EXPECT_TRUE(rv3.hasValue());
1153   EXPECT_EQ(rv3.value(), -4711);
1154   StringPiece sp4("4711");
1155   auto rv4 = folly::tryTo<uint16_t>(sp4.begin(), sp4.end());
1156   EXPECT_TRUE(rv4.hasValue());
1157   EXPECT_EQ(rv4.value(), 4711);
1158 }
1159
1160 TEST(Conv, NewUint64ToString) {
1161   char buf[21];
1162
1163 #define THE_GREAT_EXPECTATIONS(n, len)                  \
1164   do {                                                  \
1165     EXPECT_EQ((len), uint64ToBufferUnsafe((n), buf));   \
1166     buf[(len)] = 0;                                     \
1167     auto s = string(#n);                                \
1168     s = s.substr(0, s.size() - 2);                      \
1169     EXPECT_EQ(s, buf);                                  \
1170   } while (0)
1171
1172   THE_GREAT_EXPECTATIONS(0UL, 1);
1173   THE_GREAT_EXPECTATIONS(1UL, 1);
1174   THE_GREAT_EXPECTATIONS(12UL, 2);
1175   THE_GREAT_EXPECTATIONS(123UL, 3);
1176   THE_GREAT_EXPECTATIONS(1234UL, 4);
1177   THE_GREAT_EXPECTATIONS(12345UL, 5);
1178   THE_GREAT_EXPECTATIONS(123456UL, 6);
1179   THE_GREAT_EXPECTATIONS(1234567UL, 7);
1180   THE_GREAT_EXPECTATIONS(12345678UL, 8);
1181   THE_GREAT_EXPECTATIONS(123456789UL, 9);
1182   THE_GREAT_EXPECTATIONS(1234567890UL, 10);
1183   THE_GREAT_EXPECTATIONS(12345678901UL, 11);
1184   THE_GREAT_EXPECTATIONS(123456789012UL, 12);
1185   THE_GREAT_EXPECTATIONS(1234567890123UL, 13);
1186   THE_GREAT_EXPECTATIONS(12345678901234UL, 14);
1187   THE_GREAT_EXPECTATIONS(123456789012345UL, 15);
1188   THE_GREAT_EXPECTATIONS(1234567890123456UL, 16);
1189   THE_GREAT_EXPECTATIONS(12345678901234567UL, 17);
1190   THE_GREAT_EXPECTATIONS(123456789012345678UL, 18);
1191   THE_GREAT_EXPECTATIONS(1234567890123456789UL, 19);
1192   THE_GREAT_EXPECTATIONS(18446744073709551614UL, 20);
1193   THE_GREAT_EXPECTATIONS(18446744073709551615UL, 20);
1194
1195 #undef THE_GREAT_EXPECTATIONS
1196 }
1197
1198 TEST(Conv, allocate_size) {
1199   std::string str1 = "meh meh meh";
1200   std::string str2 = "zdech zdech zdech";
1201
1202   auto res1 = folly::to<std::string>(str1, ".", str2);
1203   EXPECT_EQ(res1, str1 + "." + str2);
1204
1205   std::string res2; //empty
1206   toAppendFit(str1, str2, 1, &res2);
1207   EXPECT_EQ(res2, str1 + str2 + "1");
1208
1209   std::string res3;
1210   toAppendDelimFit(",", str1, str2, &res3);
1211   EXPECT_EQ(res3, str1 + "," + str2);
1212 }
1213
1214 namespace my {
1215 struct Dimensions {
1216   int w, h;
1217   std::tuple<const int&, const int&> tuple_view() const {
1218     return tie(w, h);
1219   }
1220   bool operator==(const Dimensions& other) const {
1221     return this->tuple_view() == other.tuple_view();
1222   }
1223 };
1224
1225 Expected<StringPiece, ConversionCode> parseTo(
1226     folly::StringPiece in,
1227     Dimensions& out) {
1228   return parseTo(in, out.w)
1229       .then([](StringPiece sp) { return sp.removePrefix("x"), sp; })
1230       .then([&](StringPiece sp) { return parseTo(sp, out.h); });
1231 }
1232
1233 template <class String>
1234 void toAppend(const Dimensions& in, String* result) {
1235   folly::toAppend(in.w, 'x', in.h, result);
1236 }
1237
1238 size_t estimateSpaceNeeded(const Dimensions&in) {
1239   return 2000 + folly::estimateSpaceNeeded(in.w) +
1240       folly::estimateSpaceNeeded(in.h);
1241 }
1242 }
1243
1244 TEST(Conv, custom_kkproviders) {
1245   my::Dimensions expected{7, 8};
1246   EXPECT_EQ(expected, folly::to<my::Dimensions>("7x8"));
1247   auto str = folly::to<std::string>(expected);
1248   EXPECT_EQ("7x8", str);
1249   // make sure above implementation of estimateSpaceNeeded() is used.
1250   EXPECT_GT(str.capacity(), 2000);
1251   EXPECT_LT(str.capacity(), 2500);
1252 }
1253
1254 TEST(Conv, TryToThenWithVoid) {
1255   auto x = tryTo<int>("42").then([](int) {});
1256   EXPECT_TRUE(x.hasValue());
1257   Unit u = x.value();
1258   (void)u;
1259 }