xref: /aosp_15_r20/external/llvm-libc/src/stdio/scanf_core/core_structs.h (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
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/macros/config.h"
15 
16 #include <inttypes.h>
17 #include <stddef.h>
18 
19 namespace LIBC_NAMESPACE_DECL {
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   LIBC_INLINE 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_DECL
91 
92 #endif // LLVM_LIBC_SRC_STDIO_SCANF_CORE_CORE_STRUCTS_H
93