Rietveld Code Review Tool
Help | Bug tracker | Discussion group | Source code

Side by Side Diff: compiled/String.h

Issue 29714586: Noissue - implement a couple of common lexical_cast cases. (Closed) Base URL: github.com:adblockplus/adblockpluscore
Patch Set: address comment Created March 6, 2018, 10:35 a.m.
Left:
Right:
Use n/p to move between diff chunks; N/P to move between comments.
Jump to:
View unified diff | Download patch
« no previous file with comments | « no previous file | test/compiled/String.cpp » ('j') | no next file with comments »
Toggle Intra-line Diffs ('i') | Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
OLDNEW
1 /* 1 /*
2 * This file is part of Adblock Plus <https://adblockplus.org/>, 2 * This file is part of Adblock Plus <https://adblockplus.org/>,
3 * Copyright (C) 2006-present eyeo GmbH 3 * Copyright (C) 2006-present eyeo GmbH
4 * 4 *
5 * Adblock Plus is free software: you can redistribute it and/or modify 5 * Adblock Plus is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 3 as 6 * it under the terms of the GNU General Public License version 3 as
7 * published by the Free Software Foundation. 7 * published by the Free Software Foundation.
8 * 8 *
9 * Adblock Plus is distributed in the hope that it will be useful, 9 * Adblock Plus is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details. 12 * GNU General Public License for more details.
13 * 13 *
14 * You should have received a copy of the GNU General Public License 14 * You should have received a copy of the GNU General Public License
15 * along with Adblock Plus. If not, see <http://www.gnu.org/licenses/>. 15 * along with Adblock Plus. If not, see <http://www.gnu.org/licenses/>.
16 */ 16 */
17 17
18 #pragma once 18 #pragma once
19 19
20 #include <algorithm> 20 #include <algorithm>
21 #include <cstddef> 21 #include <cstddef>
22 #include <cstring> 22 #include <cstring>
23 #include <type_traits> 23 #include <type_traits>
24 #ifdef INSIDE_TESTS 24 #ifdef INSIDE_TESTS
25 #include <iostream> 25 #include <iostream>
26 #include <codecvt> 26 #include <codecvt>
27 #endif 27 #endif
28 #include <utility> 28 #include <utility>
29 #include <limits>
29 30
30 #include "base.h" 31 #include "base.h"
31 #include "debug.h" 32 #include "debug.h"
32 #include "library.h" 33 #include "library.h"
33 34
34 ABP_NS_BEGIN 35 ABP_NS_BEGIN
35 36
36 inline void String_assert_writable(bool isWritable); 37 inline void String_assert_writable(bool isWritable);
37 38
38 class String 39 class String
(...skipping 411 matching lines...) Expand 10 before | Expand all | Expand 10 after
450 } 451 }
451 }; 452 };
452 453
453 #ifdef INSIDE_TESTS 454 #ifdef INSIDE_TESTS
454 inline std::ostream& operator<<(std::ostream& os, const OwnedString& str) 455 inline std::ostream& operator<<(std::ostream& os, const OwnedString& str)
455 { 456 {
456 return os << static_cast<const String&>(str); 457 return os << static_cast<const String&>(str);
457 } 458 }
458 #endif 459 #endif
459 460
461 template<typename T>
462 struct LexicalCastImpl;
463
464 /// Performs common conversions of a text represented value.
465 template<typename T>
466 inline T lexical_cast(const String& value)
467 {
468 return LexicalCastImpl<T>::Convert(value);
469 }
470
471 template<>
472 struct LexicalCastImpl<bool>
473 {
474 static bool Convert(const String& value)
475 {
476 return value == u"true"_str;
477 }
478 };
479
480 template<typename T>
481 struct LexicalCastImpl
482 {
483 static_assert(std::is_integral<T>::value, "T should be a number");
484 static T Convert(const String& value)
485 {
486 String::size_type len = value.length();
487 if (len == 0)
488 return 0;
489 String::size_type pos = 0;
490 bool negative = std::numeric_limits<T>::is_signed && value[0] == u'-';
491 if (negative)
492 {
493 ++pos;
494 }
495 T result = 0;
496 for (; pos < len; ++pos)
497 {
498 auto c = value[pos];
499 if (c < u'0' || c > u'9')
500 return 0;
501 // isDangerous is the optimization because there is no need for some check s
502 // when the values are far from edge cases.
503 // It targets the normal values, when a value is prefixed with several
504 // zeros additional checks start to work earlier than the actual value of
505 // result reaches an edge case, but it does not affect the result.
506 bool isDangerous = pos >= std::numeric_limits<T>::digits10;
hub 2018/03/06 14:45:53 this check on the number of digits could also be d
sergei 2018/03/06 15:41:32 This condition is satisfied but from a different p
hub 2018/03/06 15:56:45 Acknowledged.
507 // It also invalidates the parsing of too big numbers in comparison with
508 // stopping when it encounters a non numerical character.
509 // cast<uint8_t>(u"1230"_str) -> 0
510 // cast<uint8_t>(u"123E"_str) -> 123
511 if (isDangerous && std::numeric_limits<T>::max() / 10 < result)
512 {
513 return 0;
514 }
515 result *= 10;
516 uint8_t digit = c - u'0';
517 if (isDangerous && (std::numeric_limits<T>::max() - digit < result - (nega tive ? 1 : 0)))
518 {
519 return 0;
520 }
521 result += digit;
522 }
523 return negative ? -result : result;
524 }
525 };
526
527 template<>
528 inline OwnedString lexical_cast<OwnedString>(const String& value)
529 {
530 return OwnedString{value};
531 }
532
460 DependentString TrimSpaces(const String& value); 533 DependentString TrimSpaces(const String& value);
461 534
462 // Splits the `value` string into two `DependentString`s excluding the character staying at `separatorPos`. 535 // Splits the `value` string into two `DependentString`s excluding the character staying at `separatorPos`.
463 // Useful for parsing. 536 // Useful for parsing.
464 std::pair<DependentString, DependentString> SplitString(const String& value, Str ing::size_type separatorPos); 537 std::pair<DependentString, DependentString> SplitString(const String& value, Str ing::size_type separatorPos);
465 538
466 ABP_NS_END 539 ABP_NS_END
OLDNEW
« no previous file with comments | « no previous file | test/compiled/String.cpp » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld