1 //===-- Inf or Nan Converter for printf -------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://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_PRINTF_CORE_FLOAT_INF_NAN_CONVERTER_H
10 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_FLOAT_INF_NAN_CONVERTER_H
11
12 #include "src/__support/FPUtil/FPBits.h"
13 #include "src/stdio/printf_core/converter_utils.h"
14 #include "src/stdio/printf_core/core_structs.h"
15 #include "src/stdio/printf_core/writer.h"
16
17 #include <inttypes.h>
18 #include <stddef.h>
19
20 namespace LIBC_NAMESPACE {
21 namespace printf_core {
22
23 using StorageType = fputil::FPBits<long double>::StorageType;
24
convert_inf_nan(Writer * writer,const FormatSection & to_conv)25 LIBC_INLINE int convert_inf_nan(Writer *writer, const FormatSection &to_conv) {
26 // All of the letters will be defined relative to variable a, which will be
27 // the appropriate case based on the case of the conversion.
28 const char a = (to_conv.conv_name & 32) | 'A';
29
30 bool is_negative;
31 StorageType mantissa;
32 if (to_conv.length_modifier == LengthModifier::L) {
33 fputil::FPBits<long double>::StorageType float_raw = to_conv.conv_val_raw;
34 fputil::FPBits<long double> float_bits(float_raw);
35 is_negative = float_bits.is_neg();
36 mantissa = float_bits.get_mantissa();
37 } else {
38 fputil::FPBits<double>::StorageType float_raw =
39 static_cast<fputil::FPBits<double>::StorageType>(to_conv.conv_val_raw);
40 fputil::FPBits<double> float_bits(float_raw);
41 is_negative = float_bits.is_neg();
42 mantissa = float_bits.get_mantissa();
43 }
44
45 char sign_char = 0;
46
47 if (is_negative)
48 sign_char = '-';
49 else if ((to_conv.flags & FormatFlags::FORCE_SIGN) == FormatFlags::FORCE_SIGN)
50 sign_char = '+'; // FORCE_SIGN has precedence over SPACE_PREFIX
51 else if ((to_conv.flags & FormatFlags::SPACE_PREFIX) ==
52 FormatFlags::SPACE_PREFIX)
53 sign_char = ' ';
54
55 // Both "inf" and "nan" are the same number of characters, being 3.
56 int padding = to_conv.min_width - (sign_char > 0 ? 1 : 0) - 3;
57
58 // The right justified pattern is (spaces), (sign), inf/nan
59 // The left justified pattern is (sign), inf/nan, (spaces)
60
61 if (padding > 0 && ((to_conv.flags & FormatFlags::LEFT_JUSTIFIED) !=
62 FormatFlags::LEFT_JUSTIFIED))
63 RET_IF_RESULT_NEGATIVE(writer->write(' ', padding));
64
65 if (sign_char)
66 RET_IF_RESULT_NEGATIVE(writer->write(sign_char));
67 if (mantissa == 0) { // inf
68 RET_IF_RESULT_NEGATIVE(writer->write(a == 'a' ? "inf" : "INF"));
69 } else { // nan
70 RET_IF_RESULT_NEGATIVE(writer->write(a == 'a' ? "nan" : "NAN"));
71 }
72
73 if (padding > 0 && ((to_conv.flags & FormatFlags::LEFT_JUSTIFIED) ==
74 FormatFlags::LEFT_JUSTIFIED))
75 RET_IF_RESULT_NEGATIVE(writer->write(' ', padding));
76
77 return WRITE_OK;
78 }
79
80 } // namespace printf_core
81 } // namespace LIBC_NAMESPACE
82
83 #endif // LLVM_LIBC_SRC_STDIO_PRINTF_CORE_FLOAT_INF_NAN_CONVERTER_H
84