1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
|
//===-- String to integer conversion utils ----------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// -----------------------------------------------------------------------------
// **** WARNING ****
// This file is shared with libc++. You should also be careful when adding
// dependencies to this file, since it needs to build for all libc++ targets.
// -----------------------------------------------------------------------------
#ifndef LLVM_LIBC_SRC___SUPPORT_STR_TO_INTEGER_H
#define LLVM_LIBC_SRC___SUPPORT_STR_TO_INTEGER_H
#include "hdr/errno_macros.h" // For ERANGE
#include "src/__support/CPP/limits.h"
#include "src/__support/CPP/type_traits.h"
#include "src/__support/CPP/type_traits/make_unsigned.h"
#include "src/__support/big_int.h"
#include "src/__support/common.h"
#include "src/__support/ctype_utils.h"
#include "src/__support/macros/config.h"
#include "src/__support/str_to_num_result.h"
#include "src/__support/uint128.h"
#include "src/__support/wctype_utils.h"
namespace LIBC_NAMESPACE_DECL {
namespace internal {
// Returns the idx to the first character in src that is not a whitespace
// character (as determined by isspace())
template <typename CharType>
LIBC_INLINE size_t
first_non_whitespace(const CharType *__restrict src,
size_t src_len = cpp::numeric_limits<size_t>::max()) {
size_t src_cur = 0;
for (; src_cur < src_len && internal::isspace(src[src_cur]); ++src_cur)
;
return src_cur;
}
// Returns +1, -1, or 0 if 'src' starts with (respectively)
// plus sign, minus sign, or neither.
template <typename CharType>
LIBC_INLINE static int get_sign(const CharType *__restrict src) {
if (is_char_or_wchar(src[0], '+', L'+'))
return 1;
if (is_char_or_wchar(src[0], '-', L'-'))
return -1;
return 0;
}
// checks if the next 3 characters of the string pointer are the start of a
// hexadecimal number. Does not advance the string pointer.
template <typename CharType>
LIBC_INLINE static bool is_hex_start(const CharType *__restrict src,
size_t src_len) {
if (src_len < 3)
return false;
return is_char_or_wchar(src[0], '0', L'0') &&
is_char_or_wchar(tolower(src[1]), 'x', L'x') && isalnum(src[2]) &&
b36_char_to_int(src[2]) < 16;
}
// Takes the address of the string pointer and parses the base from the start of
// it.
template <typename CharType>
LIBC_INLINE static int infer_base(const CharType *__restrict src,
size_t src_len) {
// A hexadecimal number is defined as "the prefix 0x or 0X followed by a
// sequence of the decimal digits and the letters a (or A) through f (or F)
// with values 10 through 15 respectively." (C standard 6.4.4.1)
if (is_hex_start(src, src_len))
return 16;
// An octal number is defined as "the prefix 0 optionally followed by a
// sequence of the digits 0 through 7 only" (C standard 6.4.4.1) and so any
// number that starts with 0, including just 0, is an octal number.
if (src_len > 0 && is_char_or_wchar(src[0], '0', L'0')) {
return 8;
}
// A decimal number is defined as beginning "with a nonzero digit and
// consist[ing] of a sequence of decimal digits." (C standard 6.4.4.1)
return 10;
}
// -----------------------------------------------------------------------------
// **** WARNING ****
// This interface is shared with libc++, if you change this interface you need
// to update it in both libc and libc++.
// -----------------------------------------------------------------------------
// Takes a pointer to a string and the base to convert to. This function is used
// as the backend for all of the string to int functions.
template <typename T, typename CharType>
LIBC_INLINE StrToNumResult<T>
strtointeger(const CharType *__restrict src, int base,
const size_t src_len = cpp::numeric_limits<size_t>::max()) {
using ResultType = make_integral_or_big_int_unsigned_t<T>;
if (src_len == 0)
return {0, 0, 0};
if (base < 0 || base == 1 || base > 36)
return {0, 0, EINVAL};
size_t src_cur = first_non_whitespace(src, src_len);
if (src_cur == src_len) {
return {0, 0, 0};
}
int sign = get_sign(src + src_cur);
bool is_positive = (sign >= 0);
src_cur += (sign != 0);
if (base == 0)
base = infer_base(src + src_cur, src_len - src_cur);
if (base == 16 && is_hex_start(src + src_cur, src_len - src_cur))
src_cur = src_cur + 2;
constexpr bool IS_UNSIGNED = cpp::is_unsigned_v<T>;
ResultType constexpr NEGATIVE_MAX =
!IS_UNSIGNED ? static_cast<ResultType>(cpp::numeric_limits<T>::max()) + 1
: cpp::numeric_limits<T>::max();
ResultType const abs_max =
(is_positive ? cpp::numeric_limits<T>::max() : NEGATIVE_MAX);
ResultType const abs_max_div_by_base =
abs_max / static_cast<ResultType>(base);
bool is_number = false;
int error_val = 0;
ResultType result = 0;
while (src_cur < src_len && isalnum(src[src_cur])) {
int cur_digit = b36_char_to_int(src[src_cur]);
if (cur_digit >= base)
break;
is_number = true;
++src_cur;
// If the number has already hit the maximum value for the current type then
// the result cannot change, but we still need to advance src to the end of
// the number.
if (result == abs_max) {
error_val = ERANGE;
continue;
}
if (result > abs_max_div_by_base) {
result = abs_max;
error_val = ERANGE;
} else {
result = result * static_cast<ResultType>(base);
}
if (result > abs_max - static_cast<ResultType>(cur_digit)) {
result = abs_max;
error_val = ERANGE;
} else {
result = result + static_cast<ResultType>(cur_digit);
}
}
ptrdiff_t str_len = is_number ? static_cast<ptrdiff_t>(src_cur) : 0;
if (error_val == ERANGE) {
if (is_positive || IS_UNSIGNED)
return {cpp::numeric_limits<T>::max(), str_len, error_val};
else // T is signed and there is a negative overflow
return {cpp::numeric_limits<T>::min(), str_len, error_val};
}
return {static_cast<T>(is_positive ? result : -result), str_len, error_val};
}
} // namespace internal
} // namespace LIBC_NAMESPACE_DECL
#endif // LLVM_LIBC_SRC___SUPPORT_STR_TO_INTEGER_H
|
