libc/src/stdio/baremetal/printf.cpp

   1 //===-- Implementation of printf for baremetal ------------------*- 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/stdio/printf.h"
  10 #include "src/__support/OSUtil/io.h"
  11 #include "src/__support/arg_list.h"
  12 #include "src/__support/macros/config.h"
  13 #include "src/stdio/printf_core/core_structs.h"
  14 #include "src/stdio/printf_core/printf_main.h"
  15 #include "src/stdio/printf_core/writer.h"
  16
  17 #include <stdarg.h>
  18 #include <stddef.h>
  19
  20 namespace LIBC_NAMESPACE_DECL {
  21
  22 namespace {
  23
  24 LIBC_INLINE int raw_write_hook(cpp::string_view new_str, void *) {
  25   write_to_stderr(new_str);
  26   return printf_core::WRITE_OK;
  27 }
  28
  29 } // namespace
  30
  31 LLVM_LIBC_FUNCTION(int, printf, (const char *__restrict format, ...)) {
  32   va_list vlist;
  33   va_start(vlist, format);
  34   internal::ArgList args(vlist); // This holder class allows for easier copying
  35                                  // and pointer semantics, as well as handling
  36                                  // destruction automatically.
  37   va_end(vlist);
  38   constexpr size_t BUFF_SIZE = 1024;
  39   char buffer[BUFF_SIZE];
  40
  41   printf_core::WriteBuffer wb(buffer, BUFF_SIZE, &raw_write_hook, nullptr);
  42   printf_core::Writer writer(&wb);
  43
  44   int retval = printf_core::printf_main(&writer, format, args);
  45
  46   int flushval = wb.overflow_write("");
  47   if (flushval != printf_core::WRITE_OK)
  48     retval = flushval;
  49
  50   return retval;
  51 }
  52
  53 } // namespace LIBC_NAMESPACE_DECL