libc/src/stdio/scanf_core/core_structs.h

   1 //===-- Core Structures for scanf ------------------------------*- 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_SCANF_CORE_CORE_STRUCTS_H
  10 #define LLVM_LIBC_SRC_STDIO_SCANF_CORE_CORE_STRUCTS_H
  11
  12 #include "src/__support/CPP/bitset.h"
  13 #include "src/__support/CPP/string_view.h"
  14 #include "src/__support/FPUtil/FPBits.h"
  15
  16 #include <inttypes.h>
  17 #include <stddef.h>
  18
  19 namespace LIBC_NAMESPACE {
  20 namespace scanf_core {
  21
  22 // These length modifiers match the length modifiers in the format string, which
  23 // is why they are formatted differently from the rest of the file.
  24 enum class LengthModifier { hh, h, l, ll, j, z, t, L, NONE };
  25
  26 enum FormatFlags : uint8_t {
  27   NONE = 0x00,
  28   NO_WRITE = 0x01, // *
  29   ALLOCATE = 0x02, // m
  30 };
  31
  32 struct FormatSection {
  33   bool has_conv;
  34
  35   cpp::string_view raw_string;
  36
  37   // Format Specifier Values
  38   FormatFlags flags = FormatFlags::NONE;
  39   LengthModifier length_modifier = LengthModifier::NONE;
  40   int max_width = -1;
  41
  42   // output_ptr is nullptr if and only if the NO_WRITE flag is set.
  43   void *output_ptr = nullptr;
  44
  45   char conv_name;
  46
  47   cpp::bitset<256> scan_set;
  48
  49   bool operator==(const FormatSection &other) {
  50     if (has_conv != other.has_conv)
  51       return false;
  52
  53     if (raw_string != other.raw_string)
  54       return false;
  55
  56     if (has_conv) {
  57       if (!((static_cast<uint8_t>(flags) ==
  58              static_cast<uint8_t>(other.flags)) &&
  59             (max_width == other.max_width) &&
  60             (length_modifier == other.length_modifier) &&
  61             (conv_name == other.conv_name)))
  62         return false;
  63
  64       // If the pointers are used, then they should be equal. If the NO_WRITE
  65       // flag is set or the conversion is %, then the pointers are not used.
  66       // If the pointers are used and they are not equal, return false.
  67
  68       if (!(((flags & FormatFlags::NO_WRITE) != 0) || (conv_name == '%') ||
  69             (output_ptr == other.output_ptr)))
  70         return false;
  71
  72       if (conv_name == '[')
  73         return scan_set == other.scan_set;
  74     }
  75     return true;
  76   }
  77 };
  78
  79 enum ErrorCodes : int {
  80   // This is the value to be returned by conversions when no error has occurred.
  81   READ_OK = 0,
  82   // These are the scanf return values for when an error has occurred. They are
  83   // all negative, and should be distinct.
  84   FILE_READ_ERROR = -1,
  85   FILE_STATUS_ERROR = -2,
  86   MATCHING_FAILURE = -3,
  87   ALLOCATION_FAILURE = -4,
  88 };
  89 } // namespace scanf_core
  90 } // namespace LIBC_NAMESPACE
  91
  92 #endif // LLVM_LIBC_SRC_STDIO_SCANF_CORE_CORE_STRUCTS_H