libc/src/stdio/printf_core/core_structs.h

   1 //===-- Core Structures 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_CORE_STRUCTS_H
  10 #define LLVM_LIBC_SRC_STDIO_PRINTF_CORE_CORE_STRUCTS_H
  11
  12 #include "src/__support/CPP/string_view.h"
  13 #include "src/__support/FPUtil/FPBits.h"
  14
  15 #include <inttypes.h>
  16 #include <stddef.h>
  17
  18 namespace __llvm_libc {
  19 namespace printf_core {
  20
  21 // These length modifiers match the length modifiers in the format string, which
  22 // is why they are formatted differently from the rest of the file.
  23 enum class LengthModifier { hh, h, l, ll, j, z, t, L, none };
  24
  25 enum FormatFlags : uint8_t {
  26   LEFT_JUSTIFIED = 0x01, // -
  27   FORCE_SIGN = 0x02,     // +
  28   SPACE_PREFIX = 0x04,   // space
  29   ALTERNATE_FORM = 0x08, // #
  30   LEADING_ZEROES = 0x10, // 0
  31
  32   // These flags come from the GNU extensions which aren't yet implemented.
  33   //  group_decimals = 0x20, // '
  34   //  locale_digits = 0x40,  // I
  35 };
  36
  37 struct FormatSection {
  38   bool has_conv;
  39
  40   cpp::string_view raw_string;
  41
  42   // Format Specifier Values
  43   FormatFlags flags = FormatFlags(0);
  44   LengthModifier length_modifier = LengthModifier::none;
  45   int min_width = 0;
  46   int precision = -1;
  47
  48   // Needs to be large enough to hold a long double.
  49   fputil::FPBits<long double>::UIntType conv_val_raw;
  50   void *conv_val_ptr;
  51
  52   char conv_name;
  53
  54   // This operator is only used for testing and should be automatically
  55   // optimized out for release builds.
  56   bool operator==(const FormatSection &other) {
  57     if (has_conv != other.has_conv)
  58       return false;
  59
  60     if (raw_string != other.raw_string)
  61       return false;
  62
  63     if (has_conv) {
  64       if (!((static_cast<uint8_t>(flags) ==
  65              static_cast<uint8_t>(other.flags)) &&
  66             (min_width == other.min_width) && (precision == other.precision) &&
  67             (length_modifier == other.length_modifier) &&
  68             (conv_name == other.conv_name)))
  69         return false;
  70
  71       if (conv_name == 'p' || conv_name == 'n' || conv_name == 's')
  72         return (conv_val_ptr == other.conv_val_ptr);
  73       else if (conv_name != '%')
  74         return (conv_val_raw == other.conv_val_raw);
  75     }
  76     return true;
  77   }
  78 };
  79
  80 enum PrimaryType : uint8_t { Unknown = 0, Float = 1, Pointer = 2, Integer = 3 };
  81
  82 // TypeDesc stores the information about a type that is relevant to printf in
  83 // a relatively compact manner.
  84 struct TypeDesc {
  85   uint8_t size;
  86   PrimaryType primary_type;
  87   LIBC_INLINE constexpr bool operator==(const TypeDesc &other) const {
  88     return (size == other.size) && (primary_type == other.primary_type);
  89   }
  90 };
  91
  92 template <typename T> LIBC_INLINE constexpr TypeDesc type_desc_from_type() {
  93   if constexpr (cpp::is_same_v<T, void>) {
  94     return TypeDesc{0, PrimaryType::Unknown};
  95   } else {
  96     constexpr bool isPointer = cpp::is_pointer_v<T>;
  97     constexpr bool isFloat = cpp::is_floating_point_v<T>;
  98     return TypeDesc{sizeof(T), isPointer ? PrimaryType::Pointer
  99                                : isFloat ? PrimaryType::Float
 100                                          : PrimaryType::Integer};
 101   }
 102 }
 103
 104 // This is the value to be returned by conversions when no error has occurred.
 105 constexpr int WRITE_OK = 0;
 106 // These are the printf return values for when an error has occurred. They are
 107 // all negative, and should be distinct.
 108 constexpr int FILE_WRITE_ERROR = -1;
 109 constexpr int FILE_STATUS_ERROR = -2;
 110 constexpr int NULLPTR_WRITE_ERROR = -3;
 111 constexpr int INT_CONVERSION_ERROR = -4;
 112
 113 } // namespace printf_core
 114 } // namespace __llvm_libc
 115
 116 #endif // LLVM_LIBC_SRC_STDIO_PRINTF_CORE_CORE_STRUCTS_H