1 //===-- Numeric converter for strftime --------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See htto_conv.times://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #ifndef LLVM_LIBC_SRC_STDIO_STRFTIME_CORE_NUM_CONVERTER_H
10 #define LLVM_LIBC_SRC_STDIO_STRFTIME_CORE_NUM_CONVERTER_H
11
12 #include "hdr/types/struct_tm.h"
13 #include "src/__support/CPP/string_view.h"
14 #include "src/__support/integer_to_string.h"
15 #include "src/__support/macros/config.h"
16 #include "src/stdio/printf_core/writer.h"
17 #include "src/time/strftime_core/core_structs.h"
18 #include "src/time/time_constants.h"
19 #include "src/time/time_utils.h"
20
21 namespace LIBC_NAMESPACE_DECL {
22 namespace strftime_core {
23
24 using DecFmt = IntegerToString<uintmax_t>;
25
26 struct IntFormatSection {
27 uintmax_t num = 0;
28 char sign_char = '\0';
29 size_t pad_to_len = 0;
30 char padding_char = '0';
31 };
32
33 template <printf_core::WriteMode write_mode>
write_padded_int(printf_core::Writer<write_mode> * writer,const IntFormatSection & num_info)34 LIBC_INLINE int write_padded_int(printf_core::Writer<write_mode> *writer,
35 const IntFormatSection &num_info) {
36
37 DecFmt d(num_info.num);
38 auto str = d.view();
39
40 size_t digits_written = str.size();
41
42 // one less digit of padding if there's a sign char
43 int zeroes = static_cast<int>(num_info.pad_to_len - digits_written -
44 (num_info.sign_char == 0 ? 0 : 1));
45
46 // Format is (sign) (padding) digits
47 if (num_info.sign_char != 0)
48 RET_IF_RESULT_NEGATIVE(writer->write(num_info.sign_char));
49 if (zeroes > 0)
50 RET_IF_RESULT_NEGATIVE(writer->write(num_info.padding_char, zeroes))
51 RET_IF_RESULT_NEGATIVE(writer->write(str));
52
53 return WRITE_OK;
54 }
55
get_int_format(const FormatSection & to_conv,const tm * timeptr)56 LIBC_INLINE IntFormatSection get_int_format(const FormatSection &to_conv,
57 const tm *timeptr) {
58 const time_utils::TMReader time_reader(timeptr);
59
60 intmax_t raw_num;
61
62 IntFormatSection result = {0, 0, 0, '0'};
63
64 // gets_plus_sign is only true for year conversions where the year would be
65 // positive and more than 4 digits, including leading spaces. Both the
66 // FORCE_SIGN flag and gets_plus_sign must be true for a plus sign to be
67 // output.
68 bool gets_plus_sign = false;
69
70 switch (to_conv.conv_name) {
71 case 'C': // Century [00-99]
72 raw_num = time_reader.get_year() / 100;
73 gets_plus_sign = raw_num > 99 || to_conv.min_width > 2;
74 result.pad_to_len = 2;
75 break;
76 case 'd': // Day of the month [01-31]
77 raw_num = time_reader.get_mday(); // get_mday is 1 indexed
78 result.pad_to_len = 2;
79 break;
80 case 'e': // Day of the month [1-31]
81 raw_num = time_reader.get_mday(); // get_mday is 1 indexed
82 result.pad_to_len = 2;
83 result.padding_char = ' ';
84 break;
85 case 'g': // last 2 digits of ISO year [00-99]
86 raw_num = time_reader.get_iso_year() % 100;
87 result.pad_to_len = 2;
88 break;
89 case 'G': // ISO year
90 raw_num = time_reader.get_iso_year();
91 gets_plus_sign = raw_num > 9999 || to_conv.min_width > 4;
92 result.pad_to_len = 4;
93 break;
94 case 'H': // 24-hour format [00-23]
95 raw_num = time_reader.get_hour();
96 result.pad_to_len = 2;
97 break;
98 case 'I': // 12-hour format [01-12]
99 raw_num = ((time_reader.get_hour() + 11) % 12) + 1;
100 result.pad_to_len = 2;
101 break;
102 case 'j': // Day of the year [001-366]
103 raw_num = time_reader.get_yday() + 1; // get_yday is 0 indexed
104 result.pad_to_len = 3;
105 break;
106 case 'm': // Month of the year [01-12]
107 raw_num = time_reader.get_mon() + 1; // get_mon is 0 indexed
108 result.pad_to_len = 2;
109 break;
110 case 'M': // Minute of the hour [00-59]
111 raw_num = time_reader.get_min();
112 result.pad_to_len = 2;
113 break;
114 case 's': // Seconds since the epoch
115 raw_num = time_reader.get_epoch();
116 result.pad_to_len = 0;
117 break;
118 case 'S': // Second of the minute [00-60]
119 raw_num = time_reader.get_sec();
120 result.pad_to_len = 2;
121 break;
122 case 'u': // ISO day of the week ([1-7] starting Monday)
123 raw_num = time_reader.get_iso_wday() + 1;
124 // need to add 1 because get_iso_wday returns the weekday [0-6].
125 result.pad_to_len = 1;
126 break;
127 case 'U': // Week of the year ([00-53] week 1 starts on first *Sunday*)
128 // This doesn't actually end up using tm_year, despite the standard saying
129 // it's needed. The end of the current year doesn't really matter, so leap
130 // years aren't relevant. If this is wrong, please tell me what I'm missing.
131 raw_num = time_reader.get_week(time_constants::SUNDAY);
132 result.pad_to_len = 2;
133 break;
134 case 'V': // ISO week number ([01-53], 01 is first week majority in this year)
135 // This does need to know the year, since it may affect what the week of the
136 // previous year it underflows to.
137 raw_num = time_reader.get_iso_week();
138 result.pad_to_len = 2;
139 break;
140 case 'w': // Day of week ([0-6] starting Sunday)
141 raw_num = time_reader.get_wday();
142 result.pad_to_len = 1;
143 break;
144 case 'W': // Week of the year ([00-53] week 1 starts on first *Monday*)
145 raw_num = time_reader.get_week(time_constants::MONDAY);
146 result.pad_to_len = 2;
147 break;
148 case 'y': // Year of the Century [00-99]
149 raw_num = time_reader.get_year() % 100;
150 result.pad_to_len = 2;
151 break;
152 case 'Y': // Full year
153 raw_num = time_reader.get_year();
154 gets_plus_sign = raw_num > 9999 || to_conv.min_width > 4;
155 result.pad_to_len = 4;
156 break;
157 case 'z': // Timezone offset [+/-HHMM]
158 raw_num = time_reader.get_timezone_offset();
159 result.sign_char = '+'; // force the '+' sign iff raw_num is non-negative
160 result.pad_to_len = 5; // 4 + 1 for the sign
161 break;
162 default:
163 __builtin_trap(); // this should be unreachable, but trap if you hit it.
164 }
165
166 result.num = static_cast<uintmax_t>(raw_num < 0 ? -raw_num : raw_num);
167 const bool is_negative = raw_num < 0;
168
169 // TODO: Handle locale modifiers
170
171 if ((to_conv.flags & FormatFlags::LEADING_ZEROES) ==
172 FormatFlags::LEADING_ZEROES)
173 result.padding_char = '0';
174
175 if (is_negative)
176 result.sign_char = '-';
177 else if ((to_conv.flags & FormatFlags::FORCE_SIGN) ==
178 FormatFlags::FORCE_SIGN &&
179 gets_plus_sign)
180 result.sign_char = '+';
181
182 // sign isn't a problem because we're taking the max. The result is always
183 // non-negative. Also min_width can only be 0 if it's defaulted, since 0 is a
184 // flag.
185 if (to_conv.min_width > 0)
186 result.pad_to_len = to_conv.min_width;
187
188 return result;
189 }
190
191 template <printf_core::WriteMode write_mode>
convert_int(printf_core::Writer<write_mode> * writer,const FormatSection & to_conv,const tm * timeptr)192 LIBC_INLINE int convert_int(printf_core::Writer<write_mode> *writer,
193 const FormatSection &to_conv, const tm *timeptr) {
194
195 return write_padded_int(writer, get_int_format(to_conv, timeptr));
196 }
197
198 } // namespace strftime_core
199 } // namespace LIBC_NAMESPACE_DECL
200
201 #endif
202