libc/src/stdlib/strfroml.cpp

   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