1 //===------------------------- charconv.cpp -------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #include "charconv"
11 #include <string.h>
12
13 _LIBCPP_BEGIN_NAMESPACE_STD
14
15 namespace __itoa
16 {
17
18 static constexpr char cDigitsLut[200] = {
19 '0', '0', '0', '1', '0', '2', '0', '3', '0', '4', '0', '5', '0', '6', '0',
20 '7', '0', '8', '0', '9', '1', '0', '1', '1', '1', '2', '1', '3', '1', '4',
21 '1', '5', '1', '6', '1', '7', '1', '8', '1', '9', '2', '0', '2', '1', '2',
22 '2', '2', '3', '2', '4', '2', '5', '2', '6', '2', '7', '2', '8', '2', '9',
23 '3', '0', '3', '1', '3', '2', '3', '3', '3', '4', '3', '5', '3', '6', '3',
24 '7', '3', '8', '3', '9', '4', '0', '4', '1', '4', '2', '4', '3', '4', '4',
25 '4', '5', '4', '6', '4', '7', '4', '8', '4', '9', '5', '0', '5', '1', '5',
26 '2', '5', '3', '5', '4', '5', '5', '5', '6', '5', '7', '5', '8', '5', '9',
27 '6', '0', '6', '1', '6', '2', '6', '3', '6', '4', '6', '5', '6', '6', '6',
28 '7', '6', '8', '6', '9', '7', '0', '7', '1', '7', '2', '7', '3', '7', '4',
29 '7', '5', '7', '6', '7', '7', '7', '8', '7', '9', '8', '0', '8', '1', '8',
30 '2', '8', '3', '8', '4', '8', '5', '8', '6', '8', '7', '8', '8', '8', '9',
31 '9', '0', '9', '1', '9', '2', '9', '3', '9', '4', '9', '5', '9', '6', '9',
32 '7', '9', '8', '9', '9'};
33
34 template <typename T>
35 inline _LIBCPP_INLINE_VISIBILITY char*
append1(char * buffer,T i)36 append1(char* buffer, T i)
37 {
38 *buffer = '0' + static_cast<char>(i);
39 return buffer + 1;
40 }
41
42 template <typename T>
43 inline _LIBCPP_INLINE_VISIBILITY char*
append2(char * buffer,T i)44 append2(char* buffer, T i)
45 {
46 memcpy(buffer, &cDigitsLut[(i)*2], 2);
47 return buffer + 2;
48 }
49
50 template <typename T>
51 inline _LIBCPP_INLINE_VISIBILITY char*
append3(char * buffer,T i)52 append3(char* buffer, T i)
53 {
54 return append2(append1(buffer, (i) / 100), (i) % 100);
55 }
56
57 template <typename T>
58 inline _LIBCPP_INLINE_VISIBILITY char*
append4(char * buffer,T i)59 append4(char* buffer, T i)
60 {
61 return append2(append2(buffer, (i) / 100), (i) % 100);
62 }
63
64 char*
__u32toa(uint32_t value,char * buffer)65 __u32toa(uint32_t value, char* buffer)
66 {
67 if (value < 10000)
68 {
69 if (value < 100)
70 {
71 if (value < 10)
72 buffer = append1(buffer, value);
73 else
74 buffer = append2(buffer, value);
75 }
76 else
77 {
78 if (value < 1000)
79 buffer = append3(buffer, value);
80 else
81 buffer = append4(buffer, value);
82 }
83 }
84 else if (value < 100000000)
85 {
86 // value = bbbbcccc
87 const uint32_t b = value / 10000;
88 const uint32_t c = value % 10000;
89
90 if (value < 1000000)
91 {
92 if (value < 100000)
93 buffer = append1(buffer, b);
94 else
95 buffer = append2(buffer, b);
96 }
97 else
98 {
99 if (value < 10000000)
100 buffer = append3(buffer, b);
101 else
102 buffer = append4(buffer, b);
103 }
104
105 buffer = append4(buffer, c);
106 }
107 else
108 {
109 // value = aabbbbcccc in decimal
110 const uint32_t a = value / 100000000; // 1 to 42
111 value %= 100000000;
112
113 if (a < 10)
114 buffer = append1(buffer, a);
115 else
116 buffer = append2(buffer, a);
117
118 buffer = append4(buffer, value / 10000);
119 buffer = append4(buffer, value % 10000);
120 }
121
122 return buffer;
123 }
124
125 char*
__u64toa(uint64_t value,char * buffer)126 __u64toa(uint64_t value, char* buffer)
127 {
128 if (value < 100000000)
129 {
130 uint32_t v = static_cast<uint32_t>(value);
131 if (v < 10000)
132 {
133 if (v < 100)
134 {
135 if (v < 10)
136 buffer = append1(buffer, v);
137 else
138 buffer = append2(buffer, v);
139 }
140 else
141 {
142 if (v < 1000)
143 buffer = append3(buffer, v);
144 else
145 buffer = append4(buffer, v);
146 }
147 }
148 else
149 {
150 // value = bbbbcccc
151 const uint32_t b = v / 10000;
152 const uint32_t c = v % 10000;
153
154 if (v < 1000000)
155 {
156 if (v < 100000)
157 buffer = append1(buffer, b);
158 else
159 buffer = append2(buffer, b);
160 }
161 else
162 {
163 if (v < 10000000)
164 buffer = append3(buffer, b);
165 else
166 buffer = append4(buffer, b);
167 }
168
169 buffer = append4(buffer, c);
170 }
171 }
172 else if (value < 10000000000000000)
173 {
174 const uint32_t v0 = static_cast<uint32_t>(value / 100000000);
175 const uint32_t v1 = static_cast<uint32_t>(value % 100000000);
176
177 const uint32_t b0 = v0 / 10000;
178 const uint32_t c0 = v0 % 10000;
179
180 if (v0 < 1000000)
181 {
182 if (v0 < 100000)
183 buffer = append1(buffer, b0);
184 else
185 buffer = append2(buffer, b0);
186 }
187 else
188 {
189 if (v0 < 10000000)
190 buffer = append3(buffer, b0);
191 else
192 buffer = append4(buffer, b0);
193 }
194
195 buffer = append4(buffer, c0);
196 buffer = append4(buffer, v1 / 10000);
197 buffer = append4(buffer, v1 % 10000);
198 }
199 else
200 {
201 const uint32_t a =
202 static_cast<uint32_t>(value / 10000000000000000); // 1 to 1844
203 value %= 10000000000000000;
204
205 if (a < 100)
206 {
207 if (a < 10)
208 buffer = append1(buffer, a);
209 else
210 buffer = append2(buffer, a);
211 }
212 else
213 {
214 if (a < 1000)
215 buffer = append3(buffer, a);
216 else
217 buffer = append4(buffer, a);
218 }
219
220 const uint32_t v0 = static_cast<uint32_t>(value / 100000000);
221 const uint32_t v1 = static_cast<uint32_t>(value % 100000000);
222 buffer = append4(buffer, v0 / 10000);
223 buffer = append4(buffer, v0 % 10000);
224 buffer = append4(buffer, v1 / 10000);
225 buffer = append4(buffer, v1 % 10000);
226 }
227
228 return buffer;
229 }
230
231 } // namespace __itoa
232
233 _LIBCPP_END_NAMESPACE_STD
234