xref: /aosp_15_r20/external/llvm-libc/src/stdio/baremetal/vprintf.cpp (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
1 //===-- Implementation of vprintf -------------------------------*- 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/vprintf.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 
raw_write_hook(cpp::string_view new_str,void *)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, vprintf,
32                    (const char *__restrict format, va_list vlist)) {
33   internal::ArgList args(vlist); // This holder class allows for easier copying
34                                  // and pointer semantics, as well as handling
35                                  // destruction automatically.
36   constexpr size_t BUFF_SIZE = 1024;
37   char buffer[BUFF_SIZE];
38 
39   printf_core::WriteBuffer wb(buffer, BUFF_SIZE, &raw_write_hook, nullptr);
40   printf_core::Writer writer(&wb);
41 
42   int retval = printf_core::printf_main(&writer, format, args);
43 
44   int flushval = wb.overflow_write("");
45   if (flushval != printf_core::WRITE_OK)
46     retval = flushval;
47 
48   return retval;
49 }
50 
51 } // namespace LIBC_NAMESPACE_DECL
52