libc/src/stdio/printf_core/converter_utils.h

   1 //===-- Shared Converter Utilities for printf -------------------*- 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_STDIO_PRINTF_CORE_CONVERTER_UTILS_H
  10 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_CONVERTER_UTILS_H
  11
  12 #include "src/__support/CPP/limits.h"
  13 #include "src/__support/macros/config.h"
  14 #include "src/stdio/printf_core/core_structs.h"
  15
  16 #include <inttypes.h>
  17 #include <stddef.h>
  18
  19 namespace LIBC_NAMESPACE_DECL {
  20 namespace printf_core {
  21
  22 LIBC_INLINE uintmax_t apply_length_modifier(uintmax_t num,
  23                                             LengthSpec length_spec) {
  24   auto [lm, bw] = length_spec;
  25   switch (lm) {
  26   case LengthModifier::none:
  27     return num & cpp::numeric_limits<unsigned int>::max();
  28   case LengthModifier::l:
  29     return num & cpp::numeric_limits<unsigned long>::max();
  30   case LengthModifier::ll:
  31   case LengthModifier::L:
  32     return num & cpp::numeric_limits<unsigned long long>::max();
  33   case LengthModifier::h:
  34     return num & cpp::numeric_limits<unsigned short>::max();
  35   case LengthModifier::hh:
  36     return num & cpp::numeric_limits<unsigned char>::max();
  37   case LengthModifier::z:
  38     return num & cpp::numeric_limits<size_t>::max();
  39   case LengthModifier::t:
  40     // We don't have unsigned ptrdiff so uintptr_t is used, since we need an
  41     // unsigned type and ptrdiff is usually the same size as a pointer.
  42     static_assert(sizeof(ptrdiff_t) == sizeof(uintptr_t));
  43     return num & cpp::numeric_limits<uintptr_t>::max();
  44   case LengthModifier::j:
  45     return num; // j is intmax, so no mask is necessary.
  46   case LengthModifier::w:
  47   case LengthModifier::wf: {
  48     uintmax_t mask;
  49     if (bw == 0) {
  50       mask = 0;
  51     } else if (bw < sizeof(uintmax_t) * CHAR_BIT) {
  52       mask = (static_cast<uintmax_t>(1) << bw) - 1;
  53     } else {
  54       mask = UINTMAX_MAX;
  55     }
  56     return num & mask;
  57   }
  58   }
  59   __builtin_unreachable();
  60 }
  61
  62 #define RET_IF_RESULT_NEGATIVE(func)                                           \
  63   {                                                                            \
  64     int result = (func);                                                       \
  65     if (result < 0)                                                            \
  66       return result;                                                           \
  67   }
  68
  69 // This is used to represent which direction the number should be rounded.
  70 enum class RoundDirection { Up, Down, Even };
  71
  72 } // namespace printf_core
  73 } // namespace LIBC_NAMESPACE_DECL
  74
  75 #endif // LLVM_LIBC_SRC_STDIO_PRINTF_CORE_CONVERTER_UTILS_H