xref: /aosp_15_r20/external/llvm-libc/src/stdlib/strfroml.cpp (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
1 //===-- Implementation of strfroml ------------------------------*- 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 #include "src/stdlib/strfroml.h"
10 #include "src/__support/macros/config.h"
11 #include "src/stdlib/str_from_util.h"
12 
13 namespace LIBC_NAMESPACE_DECL {
14 
15 LLVM_LIBC_FUNCTION(int, strfroml,
16                    (char *__restrict s, size_t n, const char *__restrict format,
17                     long double fp)) {
18   LIBC_ASSERT(s != nullptr);
19 
20   printf_core::FormatSection section =
21       internal::parse_format_string(format, fp);
22 
23   // To ensure that the conversion function actually uses long double,
24   // the length modifier has to be set to LenghtModifier::L
25   section.length_modifier = printf_core::LengthModifier::L;
26 
27   printf_core::WriteBuffer wb(s, (n > 0 ? n - 1 : 0));
28   printf_core::Writer writer(&wb);
29 
30   int result = 0;
31   if (section.has_conv)
32     result = internal::strfromfloat_convert<long double>(&writer, section);
33   else
34     result = writer.write(section.raw_string);
35 
36   if (result < 0)
37     return result;
38 
39   if (n > 0)
40     wb.buff[wb.buff_cur] = '\0';
41 
42   return writer.get_chars_written();
43 }
44 
45 } // namespace LIBC_NAMESPACE_DECL
46