libc/src/stdio/sscanf.cpp

   1 //===-- Implementation of sscanf --------------------------------*- 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/sscanf.h"
  10
  11 #include "src/__support/CPP/limits.h"
  12 #include "src/__support/arg_list.h"
  13 #include "src/stdio/scanf_core/reader.h"
  14 #include "src/stdio/scanf_core/scanf_main.h"
  15
  16 #include <stdarg.h>
  17 #include <stdio.h>
  18
  19 namespace __llvm_libc {
  20
  21 LLVM_LIBC_FUNCTION(int, sscanf,
  22                    (const char *__restrict buffer,
  23                     const char *__restrict format, ...)) {
  24   va_list vlist;
  25   va_start(vlist, format);
  26   internal::ArgList args(vlist); // This holder class allows for easier copying
  27                                  // and pointer semantics, as well as handling
  28                                  // destruction automatically.
  29   va_end(vlist);
  30   scanf_core::ReadBuffer rb{const_cast<char *>(buffer),
  31                             cpp::numeric_limits<size_t>::max()};
  32   scanf_core::Reader reader(&rb);
  33   int ret_val = scanf_core::scanf_main(&reader, format, args);
  34   // This is done to avoid including stdio.h in the internals. On most systems
  35   // EOF is -1, so this will be transformed into just "return ret_val".
  36   return (ret_val == -1) ? EOF : ret_val;
  37 }
  38
  39 } // namespace __llvm_libc