libc/src/__support/arg_list.h

   1 //===-- Holder Class for manipulating va_lists ------------------*- 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 #ifndef LLVM_LIBC_SRC_SUPPORT_ARG_LIST_H
  10 #define LLVM_LIBC_SRC_SUPPORT_ARG_LIST_H
  11
  12 #include "src/__support/common.h"
  13
  14 #include <stdarg.h>
  15 #include <stddef.h>
  16
  17 namespace __llvm_libc {
  18 namespace internal {
  19
  20 class ArgList {
  21   va_list vlist;
  22
  23 public:
  24   LIBC_INLINE ArgList(va_list vlist) { va_copy(this->vlist, vlist); }
  25   LIBC_INLINE ArgList(ArgList &other) { va_copy(this->vlist, other.vlist); }
  26   LIBC_INLINE ~ArgList() { va_end(this->vlist); }
  27
  28   LIBC_INLINE ArgList &operator=(ArgList &rhs) {
  29     va_copy(vlist, rhs.vlist);
  30     return *this;
  31   }
  32
  33   template <class T> LIBC_INLINE T next_var() { return va_arg(vlist, T); }
  34 };
  35
  36 // Used for testing things that use an ArgList when it's impossible to know what
  37 // the arguments should be ahead of time. An example of this would be fuzzing,
  38 // since a function passed a random input could request unpredictable arguments.
  39 class MockArgList {
  40   size_t arg_counter = 0;
  41
  42 public:
  43   LIBC_INLINE MockArgList() = default;
  44   LIBC_INLINE MockArgList(va_list) { ; }
  45   LIBC_INLINE MockArgList(MockArgList &other) {
  46     arg_counter = other.arg_counter;
  47   }
  48   LIBC_INLINE ~MockArgList() = default;
  49
  50   LIBC_INLINE MockArgList &operator=(MockArgList &rhs) {
  51     arg_counter = rhs.arg_counter;
  52     return *this;
  53   }
  54
  55   template <class T> LIBC_INLINE T next_var() {
  56     ++arg_counter;
  57     return T(arg_counter);
  58   }
  59
  60   size_t read_count() const { return arg_counter; }
  61 };
  62
  63 } // namespace internal
  64 } // namespace __llvm_libc
  65
  66 #endif // LLVM_LIBC_SRC_SUPPORT_ARG_LIST_H