xref: /freebsd/contrib/llvm-project/libcxx/include/charconv (revision 2f513db72b034fd5ef7f080b11be5c711c15186a)
1// -*- C++ -*-
2//===------------------------------ charconv ------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_CHARCONV
11#define _LIBCPP_CHARCONV
12
13/*
14    charconv synopsis
15
16namespace std {
17
18  // floating-point format for primitive numerical conversion
19  enum class chars_format {
20    scientific = unspecified,
21    fixed = unspecified,
22    hex = unspecified,
23    general = fixed | scientific
24  };
25
26  // 23.20.2, primitive numerical output conversion
27  struct to_chars_result {
28    char* ptr;
29    errc ec;
30  };
31
32  to_chars_result to_chars(char* first, char* last, see below value,
33                           int base = 10);
34
35  to_chars_result to_chars(char* first, char* last, float value);
36  to_chars_result to_chars(char* first, char* last, double value);
37  to_chars_result to_chars(char* first, char* last, long double value);
38
39  to_chars_result to_chars(char* first, char* last, float value,
40                           chars_format fmt);
41  to_chars_result to_chars(char* first, char* last, double value,
42                           chars_format fmt);
43  to_chars_result to_chars(char* first, char* last, long double value,
44                           chars_format fmt);
45
46  to_chars_result to_chars(char* first, char* last, float value,
47                           chars_format fmt, int precision);
48  to_chars_result to_chars(char* first, char* last, double value,
49                           chars_format fmt, int precision);
50  to_chars_result to_chars(char* first, char* last, long double value,
51                           chars_format fmt, int precision);
52
53  // 23.20.3, primitive numerical input conversion
54  struct from_chars_result {
55    const char* ptr;
56    errc ec;
57  };
58
59  from_chars_result from_chars(const char* first, const char* last,
60                               see below& value, int base = 10);
61
62  from_chars_result from_chars(const char* first, const char* last,
63                               float& value,
64                               chars_format fmt = chars_format::general);
65  from_chars_result from_chars(const char* first, const char* last,
66                               double& value,
67                               chars_format fmt = chars_format::general);
68  from_chars_result from_chars(const char* first, const char* last,
69                               long double& value,
70                               chars_format fmt = chars_format::general);
71
72} // namespace std
73
74*/
75
76#include <__errc>
77#include <type_traits>
78#include <limits>
79#include <stdint.h>
80#include <string.h>
81#include <math.h>
82
83#include <__debug>
84
85#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
86#pragma GCC system_header
87#endif
88
89_LIBCPP_PUSH_MACROS
90#include <__undef_macros>
91
92_LIBCPP_BEGIN_NAMESPACE_STD
93
94namespace __itoa {
95_LIBCPP_FUNC_VIS char* __u64toa(uint64_t __value, char* __buffer);
96_LIBCPP_FUNC_VIS char* __u32toa(uint32_t __value, char* __buffer);
97}
98
99#ifndef _LIBCPP_CXX03_LANG
100
101enum class _LIBCPP_ENUM_VIS chars_format
102{
103    scientific = 0x1,
104    fixed = 0x2,
105    hex = 0x4,
106    general = fixed | scientific
107};
108
109struct _LIBCPP_TYPE_VIS to_chars_result
110{
111    char* ptr;
112    errc ec;
113};
114
115struct _LIBCPP_TYPE_VIS from_chars_result
116{
117    const char* ptr;
118    errc ec;
119};
120
121void to_chars(char*, char*, bool, int = 10) = delete;
122void from_chars(const char*, const char*, bool, int = 10) = delete;
123
124namespace __itoa
125{
126
127static _LIBCPP_CONSTEXPR uint64_t __pow10_64[] = {
128    UINT64_C(0),
129    UINT64_C(10),
130    UINT64_C(100),
131    UINT64_C(1000),
132    UINT64_C(10000),
133    UINT64_C(100000),
134    UINT64_C(1000000),
135    UINT64_C(10000000),
136    UINT64_C(100000000),
137    UINT64_C(1000000000),
138    UINT64_C(10000000000),
139    UINT64_C(100000000000),
140    UINT64_C(1000000000000),
141    UINT64_C(10000000000000),
142    UINT64_C(100000000000000),
143    UINT64_C(1000000000000000),
144    UINT64_C(10000000000000000),
145    UINT64_C(100000000000000000),
146    UINT64_C(1000000000000000000),
147    UINT64_C(10000000000000000000),
148};
149
150static _LIBCPP_CONSTEXPR uint32_t __pow10_32[] = {
151    UINT32_C(0),          UINT32_C(10),       UINT32_C(100),
152    UINT32_C(1000),       UINT32_C(10000),    UINT32_C(100000),
153    UINT32_C(1000000),    UINT32_C(10000000), UINT32_C(100000000),
154    UINT32_C(1000000000),
155};
156
157template <typename _Tp, typename = void>
158struct _LIBCPP_HIDDEN __traits_base
159{
160    using type = uint64_t;
161
162#if !defined(_LIBCPP_COMPILER_MSVC)
163    static _LIBCPP_INLINE_VISIBILITY int __width(_Tp __v)
164    {
165        auto __t = (64 - __builtin_clzll(__v | 1)) * 1233 >> 12;
166        return __t - (__v < __pow10_64[__t]) + 1;
167    }
168#endif
169
170    static _LIBCPP_INLINE_VISIBILITY char* __convert(_Tp __v, char* __p)
171    {
172        return __u64toa(__v, __p);
173    }
174
175    static _LIBCPP_INLINE_VISIBILITY decltype(__pow10_64)& __pow() { return __pow10_64; }
176};
177
178template <typename _Tp>
179struct _LIBCPP_HIDDEN
180    __traits_base<_Tp, decltype(void(uint32_t{declval<_Tp>()}))>
181{
182    using type = uint32_t;
183
184#if !defined(_LIBCPP_COMPILER_MSVC)
185    static _LIBCPP_INLINE_VISIBILITY int __width(_Tp __v)
186    {
187        auto __t = (32 - __builtin_clz(__v | 1)) * 1233 >> 12;
188        return __t - (__v < __pow10_32[__t]) + 1;
189    }
190#endif
191
192    static _LIBCPP_INLINE_VISIBILITY char* __convert(_Tp __v, char* __p)
193    {
194        return __u32toa(__v, __p);
195    }
196
197    static _LIBCPP_INLINE_VISIBILITY decltype(__pow10_32)& __pow() { return __pow10_32; }
198};
199
200template <typename _Tp>
201inline _LIBCPP_INLINE_VISIBILITY bool
202__mul_overflowed(unsigned char __a, _Tp __b, unsigned char& __r)
203{
204    auto __c = __a * __b;
205    __r = __c;
206    return __c > (numeric_limits<unsigned char>::max)();
207}
208
209template <typename _Tp>
210inline _LIBCPP_INLINE_VISIBILITY bool
211__mul_overflowed(unsigned short __a, _Tp __b, unsigned short& __r)
212{
213    auto __c = __a * __b;
214    __r = __c;
215    return __c > (numeric_limits<unsigned short>::max)();
216}
217
218template <typename _Tp>
219inline _LIBCPP_INLINE_VISIBILITY bool
220__mul_overflowed(_Tp __a, _Tp __b, _Tp& __r)
221{
222    static_assert(is_unsigned<_Tp>::value, "");
223#if !defined(_LIBCPP_COMPILER_MSVC)
224    return __builtin_mul_overflow(__a, __b, &__r);
225#else
226    bool __did = __b && ((numeric_limits<_Tp>::max)() / __b) < __a;
227    __r = __a * __b;
228    return __did;
229#endif
230}
231
232template <typename _Tp, typename _Up>
233inline _LIBCPP_INLINE_VISIBILITY bool
234__mul_overflowed(_Tp __a, _Up __b, _Tp& __r)
235{
236    return __mul_overflowed(__a, static_cast<_Tp>(__b), __r);
237}
238
239template <typename _Tp>
240struct _LIBCPP_HIDDEN __traits : __traits_base<_Tp>
241{
242    static _LIBCPP_CONSTEXPR int digits = numeric_limits<_Tp>::digits10 + 1;
243    using __traits_base<_Tp>::__pow;
244    using typename __traits_base<_Tp>::type;
245
246    // precondition: at least one non-zero character available
247    static _LIBCPP_INLINE_VISIBILITY char const*
248    __read(char const* __p, char const* __ep, type& __a, type& __b)
249    {
250        type __cprod[digits];
251        int __j = digits - 1;
252        int __i = digits;
253        do
254        {
255            if (!('0' <= *__p && *__p <= '9'))
256                break;
257            __cprod[--__i] = *__p++ - '0';
258        } while (__p != __ep && __i != 0);
259
260        __a = __inner_product(__cprod + __i + 1, __cprod + __j, __pow() + 1,
261                              __cprod[__i]);
262        if (__mul_overflowed(__cprod[__j], __pow()[__j - __i], __b))
263            --__p;
264        return __p;
265    }
266
267    template <typename _It1, typename _It2, class _Up>
268    static _LIBCPP_INLINE_VISIBILITY _Up
269    __inner_product(_It1 __first1, _It1 __last1, _It2 __first2, _Up __init)
270    {
271        for (; __first1 < __last1; ++__first1, ++__first2)
272            __init = __init + *__first1 * *__first2;
273        return __init;
274    }
275};
276
277}  // namespace __itoa
278
279template <typename _Tp>
280inline _LIBCPP_INLINE_VISIBILITY _Tp
281__complement(_Tp __x)
282{
283    static_assert(is_unsigned<_Tp>::value, "cast to unsigned first");
284    return _Tp(~__x + 1);
285}
286
287template <typename _Tp>
288inline _LIBCPP_INLINE_VISIBILITY typename make_unsigned<_Tp>::type
289__to_unsigned(_Tp __x)
290{
291    return static_cast<typename make_unsigned<_Tp>::type>(__x);
292}
293
294template <typename _Tp>
295inline _LIBCPP_INLINE_VISIBILITY to_chars_result
296__to_chars_itoa(char* __first, char* __last, _Tp __value, true_type)
297{
298    auto __x = __to_unsigned(__value);
299    if (__value < 0 && __first != __last)
300    {
301        *__first++ = '-';
302        __x = __complement(__x);
303    }
304
305    return __to_chars_itoa(__first, __last, __x, false_type());
306}
307
308template <typename _Tp>
309inline _LIBCPP_INLINE_VISIBILITY to_chars_result
310__to_chars_itoa(char* __first, char* __last, _Tp __value, false_type)
311{
312    using __tx = __itoa::__traits<_Tp>;
313    auto __diff = __last - __first;
314
315#if !defined(_LIBCPP_COMPILER_MSVC)
316    if (__tx::digits <= __diff || __tx::__width(__value) <= __diff)
317        return {__tx::__convert(__value, __first), errc(0)};
318    else
319        return {__last, errc::value_too_large};
320#else
321    if (__tx::digits <= __diff)
322        return {__tx::__convert(__value, __first), {}};
323    else
324    {
325        char __buf[__tx::digits];
326        auto __p = __tx::__convert(__value, __buf);
327        auto __len = __p - __buf;
328        if (__len <= __diff)
329        {
330            memcpy(__first, __buf, __len);
331            return {__first + __len, {}};
332        }
333        else
334            return {__last, errc::value_too_large};
335    }
336#endif
337}
338
339template <typename _Tp>
340inline _LIBCPP_INLINE_VISIBILITY to_chars_result
341__to_chars_integral(char* __first, char* __last, _Tp __value, int __base,
342                    true_type)
343{
344    auto __x = __to_unsigned(__value);
345    if (__value < 0 && __first != __last)
346    {
347        *__first++ = '-';
348        __x = __complement(__x);
349    }
350
351    return __to_chars_integral(__first, __last, __x, __base, false_type());
352}
353
354template <typename _Tp>
355inline _LIBCPP_INLINE_VISIBILITY to_chars_result
356__to_chars_integral(char* __first, char* __last, _Tp __value, int __base,
357                    false_type)
358{
359    if (__base == 10)
360        return __to_chars_itoa(__first, __last, __value, false_type());
361
362    auto __p = __last;
363    while (__p != __first)
364    {
365        auto __c = __value % __base;
366        __value /= __base;
367        *--__p = "0123456789abcdefghijklmnopqrstuvwxyz"[__c];
368        if (__value == 0)
369            break;
370    }
371
372    auto __len = __last - __p;
373    if (__value != 0 || !__len)
374        return {__last, errc::value_too_large};
375    else
376    {
377        memmove(__first, __p, __len);
378        return {__first + __len, {}};
379    }
380}
381
382template <typename _Tp, typename enable_if<is_integral<_Tp>::value, int>::type = 0>
383inline _LIBCPP_INLINE_VISIBILITY to_chars_result
384to_chars(char* __first, char* __last, _Tp __value)
385{
386    return __to_chars_itoa(__first, __last, __value, is_signed<_Tp>());
387}
388
389template <typename _Tp, typename enable_if<is_integral<_Tp>::value, int>::type = 0>
390inline _LIBCPP_INLINE_VISIBILITY to_chars_result
391to_chars(char* __first, char* __last, _Tp __value, int __base)
392{
393    _LIBCPP_ASSERT(2 <= __base && __base <= 36, "base not in [2, 36]");
394    return __to_chars_integral(__first, __last, __value, __base,
395                               is_signed<_Tp>());
396}
397
398template <typename _It, typename _Tp, typename _Fn, typename... _Ts>
399inline _LIBCPP_INLINE_VISIBILITY from_chars_result
400__sign_combinator(_It __first, _It __last, _Tp& __value, _Fn __f, _Ts... __args)
401{
402    using __tl = numeric_limits<_Tp>;
403    decltype(__to_unsigned(__value)) __x;
404
405    bool __neg = (__first != __last && *__first == '-');
406    auto __r = __f(__neg ? __first + 1 : __first, __last, __x, __args...);
407    switch (__r.ec)
408    {
409    case errc::invalid_argument:
410        return {__first, __r.ec};
411    case errc::result_out_of_range:
412        return __r;
413    default:
414        break;
415    }
416
417    if (__neg)
418    {
419        if (__x <= __complement(__to_unsigned(__tl::min())))
420        {
421            __x = __complement(__x);
422            memcpy(&__value, &__x, sizeof(__x));
423            return __r;
424        }
425    }
426    else
427    {
428        if (__x <= (__tl::max)())
429        {
430            __value = __x;
431            return __r;
432        }
433    }
434
435    return {__r.ptr, errc::result_out_of_range};
436}
437
438template <typename _Tp>
439inline _LIBCPP_INLINE_VISIBILITY bool
440__in_pattern(_Tp __c)
441{
442    return '0' <= __c && __c <= '9';
443}
444
445struct _LIBCPP_HIDDEN __in_pattern_result
446{
447    bool __ok;
448    int __val;
449
450    explicit _LIBCPP_INLINE_VISIBILITY operator bool() const { return __ok; }
451};
452
453template <typename _Tp>
454inline _LIBCPP_INLINE_VISIBILITY __in_pattern_result
455__in_pattern(_Tp __c, int __base)
456{
457    if (__base <= 10)
458        return {'0' <= __c && __c < '0' + __base, __c - '0'};
459    else if (__in_pattern(__c))
460        return {true, __c - '0'};
461    else if ('a' <= __c && __c < 'a' + __base - 10)
462        return {true, __c - 'a' + 10};
463    else
464        return {'A' <= __c && __c < 'A' + __base - 10, __c - 'A' + 10};
465}
466
467template <typename _It, typename _Tp, typename _Fn, typename... _Ts>
468inline _LIBCPP_INLINE_VISIBILITY from_chars_result
469__subject_seq_combinator(_It __first, _It __last, _Tp& __value, _Fn __f,
470                         _Ts... __args)
471{
472    auto __find_non_zero = [](_It __first, _It __last) {
473        for (; __first != __last; ++__first)
474            if (*__first != '0')
475                break;
476        return __first;
477    };
478
479    auto __p = __find_non_zero(__first, __last);
480    if (__p == __last || !__in_pattern(*__p, __args...))
481    {
482        if (__p == __first)
483            return {__first, errc::invalid_argument};
484        else
485        {
486            __value = 0;
487            return {__p, {}};
488        }
489    }
490
491    auto __r = __f(__p, __last, __value, __args...);
492    if (__r.ec == errc::result_out_of_range)
493    {
494        for (; __r.ptr != __last; ++__r.ptr)
495        {
496            if (!__in_pattern(*__r.ptr, __args...))
497                break;
498        }
499    }
500
501    return __r;
502}
503
504template <typename _Tp, typename enable_if<is_unsigned<_Tp>::value, int>::type = 0>
505inline _LIBCPP_INLINE_VISIBILITY from_chars_result
506__from_chars_atoi(const char* __first, const char* __last, _Tp& __value)
507{
508    using __tx = __itoa::__traits<_Tp>;
509    using __output_type = typename __tx::type;
510
511    return __subject_seq_combinator(
512        __first, __last, __value,
513        [](const char* __first, const char* __last,
514           _Tp& __value) -> from_chars_result {
515            __output_type __a, __b;
516            auto __p = __tx::__read(__first, __last, __a, __b);
517            if (__p == __last || !__in_pattern(*__p))
518            {
519                __output_type __m = (numeric_limits<_Tp>::max)();
520                if (__m >= __a && __m - __a >= __b)
521                {
522                    __value = __a + __b;
523                    return {__p, {}};
524                }
525            }
526            return {__p, errc::result_out_of_range};
527        });
528}
529
530template <typename _Tp, typename enable_if<is_signed<_Tp>::value, int>::type = 0>
531inline _LIBCPP_INLINE_VISIBILITY from_chars_result
532__from_chars_atoi(const char* __first, const char* __last, _Tp& __value)
533{
534    using __t = decltype(__to_unsigned(__value));
535    return __sign_combinator(__first, __last, __value, __from_chars_atoi<__t>);
536}
537
538template <typename _Tp, typename enable_if<is_unsigned<_Tp>::value, int>::type = 0>
539inline _LIBCPP_INLINE_VISIBILITY from_chars_result
540__from_chars_integral(const char* __first, const char* __last, _Tp& __value,
541                      int __base)
542{
543    if (__base == 10)
544        return __from_chars_atoi(__first, __last, __value);
545
546    return __subject_seq_combinator(
547        __first, __last, __value,
548        [](const char* __p, const char* __last, _Tp& __value,
549           int __base) -> from_chars_result {
550            using __tl = numeric_limits<_Tp>;
551            auto __digits = __tl::digits / log2f(float(__base));
552            _Tp __a = __in_pattern(*__p++, __base).__val, __b = 0;
553
554            for (int __i = 1; __p != __last; ++__i, ++__p)
555            {
556                if (auto __c = __in_pattern(*__p, __base))
557                {
558                    if (__i < __digits - 1)
559                        __a = __a * __base + __c.__val;
560                    else
561                    {
562                        if (!__itoa::__mul_overflowed(__a, __base, __a))
563                            ++__p;
564                        __b = __c.__val;
565                        break;
566                    }
567                }
568                else
569                    break;
570            }
571
572            if (__p == __last || !__in_pattern(*__p, __base))
573            {
574                if ((__tl::max)() - __a >= __b)
575                {
576                    __value = __a + __b;
577                    return {__p, {}};
578                }
579            }
580            return {__p, errc::result_out_of_range};
581        },
582        __base);
583}
584
585template <typename _Tp, typename enable_if<is_signed<_Tp>::value, int>::type = 0>
586inline _LIBCPP_INLINE_VISIBILITY from_chars_result
587__from_chars_integral(const char* __first, const char* __last, _Tp& __value,
588                      int __base)
589{
590    using __t = decltype(__to_unsigned(__value));
591    return __sign_combinator(__first, __last, __value,
592                             __from_chars_integral<__t>, __base);
593}
594
595template <typename _Tp, typename enable_if<is_integral<_Tp>::value, int>::type = 0>
596inline _LIBCPP_INLINE_VISIBILITY from_chars_result
597from_chars(const char* __first, const char* __last, _Tp& __value)
598{
599    return __from_chars_atoi(__first, __last, __value);
600}
601
602template <typename _Tp, typename enable_if<is_integral<_Tp>::value, int>::type = 0>
603inline _LIBCPP_INLINE_VISIBILITY from_chars_result
604from_chars(const char* __first, const char* __last, _Tp& __value, int __base)
605{
606    _LIBCPP_ASSERT(2 <= __base && __base <= 36, "base not in [2, 36]");
607    return __from_chars_integral(__first, __last, __value, __base);
608}
609
610#endif  // _LIBCPP_CXX03_LANG
611
612_LIBCPP_END_NAMESPACE_STD
613
614_LIBCPP_POP_MACROS
615
616#endif  // _LIBCPP_CHARCONV
617