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/macros/config.h"
  13
  14 #include "src/__support/CPP/string_view.h"
  15 #include "src/__support/CPP/type_traits.h"
  16 #include "src/__support/FPUtil/FPBits.h"
  17 #include "src/stdio/printf_core/printf_config.h"
  18
  19 #include <inttypes.h>
  20 #include <stddef.h>
  21
  22 namespace LIBC_NAMESPACE_DECL {
  23 namespace printf_core {
  24
  25 // These length modifiers match the length modifiers in the format string, which
  26 // is why they are formatted differently from the rest of the file.
  27 enum class LengthModifier { hh, h, l, ll, j, z, t, L, w, wf, none };
  28
  29 struct LengthSpec {
  30   LengthModifier lm;
  31   size_t bit_width;
  32 };
  33
  34 enum FormatFlags : uint8_t {
  35   LEFT_JUSTIFIED = 0x01, // -
  36   FORCE_SIGN = 0x02,     // +
  37   SPACE_PREFIX = 0x04,   // space
  38   ALTERNATE_FORM = 0x08, // #
  39   LEADING_ZEROES = 0x10, // 0
  40
  41   // These flags come from the GNU extensions which aren't yet implemented.
  42   //  group_decimals = 0x20, // '
  43   //  locale_digits = 0x40,  // I
  44 };
  45
  46 struct FormatSection {
  47   bool has_conv;
  48
  49   cpp::string_view raw_string;
  50
  51   // Format Specifier Values
  52   FormatFlags flags = FormatFlags(0);
  53   LengthModifier length_modifier = LengthModifier::none;
  54   size_t bit_width = 0;
  55   int min_width = 0;
  56   int precision = -1;
  57
  58   // Needs to be large enough to hold a long double.
  59   fputil::FPBits<long double>::StorageType conv_val_raw;
  60   void *conv_val_ptr;
  61
  62   char conv_name;
  63
  64   // This operator is only used for testing and should be automatically
  65   // optimized out for release builds.
  66   LIBC_INLINE bool operator==(const FormatSection &other) const {
  67     if (has_conv != other.has_conv)
  68       return false;
  69
  70     if (raw_string != other.raw_string)
  71       return false;
  72
  73     if (has_conv) {
  74       if (!((static_cast<uint8_t>(flags) ==
  75              static_cast<uint8_t>(other.flags)) &&
  76             (min_width == other.min_width) && (precision == other.precision) &&
  77             (bit_width == other.bit_width) &&
  78             (length_modifier == other.length_modifier) &&
  79             (conv_name == other.conv_name)))
  80         return false;
  81
  82       if (conv_name == 'p' || conv_name == 'n' || conv_name == 's')
  83         return (conv_val_ptr == other.conv_val_ptr);
  84       else if (conv_name != '%')
  85         return (conv_val_raw == other.conv_val_raw);
  86     }
  87     return true;
  88   }
  89 };
  90
  91 enum PrimaryType : uint8_t {
  92   Unknown = 0,
  93   Float = 1,
  94   Pointer = 2,
  95   Integer = 3,
  96   FixedPoint = 4,
  97 };
  98
  99 // TypeDesc stores the information about a type that is relevant to printf in
 100 // a relatively compact manner.
 101 struct TypeDesc {
 102   uint8_t size;
 103   PrimaryType primary_type;
 104   LIBC_INLINE constexpr bool operator==(const TypeDesc &other) const {
 105     return (size == other.size) && (primary_type == other.primary_type);
 106   }
 107 };
 108
 109 template <typename T> LIBC_INLINE constexpr TypeDesc type_desc_from_type() {
 110   if constexpr (cpp::is_same_v<T, void>) {
 111     return TypeDesc{0, PrimaryType::Unknown};
 112   } else {
 113     constexpr bool IS_POINTER = cpp::is_pointer_v<T>;
 114     constexpr bool IS_FLOAT = cpp::is_floating_point_v<T>;
 115 #ifdef LIBC_INTERNAL_PRINTF_HAS_FIXED_POINT
 116     constexpr bool IS_FIXED_POINT = cpp::is_fixed_point_v<T>;
 117 #else
 118     constexpr bool IS_FIXED_POINT = false;
 119 #endif // LIBC_INTERNAL_PRINTF_HAS_FIXED_POINT
 120
 121     return TypeDesc{sizeof(T), IS_POINTER       ? PrimaryType::Pointer
 122                                : IS_FLOAT       ? PrimaryType::Float
 123                                : IS_FIXED_POINT ? PrimaryType::FixedPoint
 124                                                 : PrimaryType::Integer};
 125   }
 126 }
 127
 128 // This is the value to be returned by conversions when no error has occurred.
 129 constexpr int WRITE_OK = 0;
 130 // These are the printf return values for when an error has occurred. They are
 131 // all negative, and should be distinct.
 132 constexpr int FILE_WRITE_ERROR = -1;
 133 constexpr int FILE_STATUS_ERROR = -2;
 134 constexpr int NULLPTR_WRITE_ERROR = -3;
 135 constexpr int INT_CONVERSION_ERROR = -4;
 136 constexpr int FIXED_POINT_CONVERSION_ERROR = -5;
 137 constexpr int ALLOCATION_ERROR = -6;
 138 } // namespace printf_core
 139 } // namespace LIBC_NAMESPACE_DECL
 140
 141 #endif // LLVM_LIBC_SRC_STDIO_PRINTF_CORE_CORE_STRUCTS_H