Andrew Scull | 5e1ddfa | 2018-08-14 10:06:54 +0100 | [diff] [blame^] | 1 | //===- YAML.h ---------------------------------------------------*- C++ -*-===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | |
| 10 | #ifndef LLVM_OBJECTYAML_YAML_H |
| 11 | #define LLVM_OBJECTYAML_YAML_H |
| 12 | |
| 13 | #include "llvm/ADT/ArrayRef.h" |
| 14 | #include "llvm/ADT/StringRef.h" |
| 15 | #include "llvm/Support/YAMLTraits.h" |
| 16 | #include <cstdint> |
| 17 | |
| 18 | namespace llvm { |
| 19 | |
| 20 | class raw_ostream; |
| 21 | |
| 22 | namespace yaml { |
| 23 | |
| 24 | /// \brief Specialized YAMLIO scalar type for representing a binary blob. |
| 25 | /// |
| 26 | /// A typical use case would be to represent the content of a section in a |
| 27 | /// binary file. |
| 28 | /// This class has custom YAMLIO traits for convenient reading and writing. |
| 29 | /// It renders as a string of hex digits in a YAML file. |
| 30 | /// For example, it might render as `DEADBEEFCAFEBABE` (YAML does not |
| 31 | /// require the quotation marks, so for simplicity when outputting they are |
| 32 | /// omitted). |
| 33 | /// When reading, any string whose content is an even number of hex digits |
| 34 | /// will be accepted. |
| 35 | /// For example, all of the following are acceptable: |
| 36 | /// `DEADBEEF`, `"DeADbEeF"`, `"\x44EADBEEF"` (Note: '\x44' == 'D') |
| 37 | /// |
| 38 | /// A significant advantage of using this class is that it never allocates |
| 39 | /// temporary strings or buffers for any of its functionality. |
| 40 | /// |
| 41 | /// Example: |
| 42 | /// |
| 43 | /// The YAML mapping: |
| 44 | /// \code |
| 45 | /// Foo: DEADBEEFCAFEBABE |
| 46 | /// \endcode |
| 47 | /// |
| 48 | /// Could be modeled in YAMLIO by the struct: |
| 49 | /// \code |
| 50 | /// struct FooHolder { |
| 51 | /// BinaryRef Foo; |
| 52 | /// }; |
| 53 | /// namespace llvm { |
| 54 | /// namespace yaml { |
| 55 | /// template <> |
| 56 | /// struct MappingTraits<FooHolder> { |
| 57 | /// static void mapping(IO &IO, FooHolder &FH) { |
| 58 | /// IO.mapRequired("Foo", FH.Foo); |
| 59 | /// } |
| 60 | /// }; |
| 61 | /// } // end namespace yaml |
| 62 | /// } // end namespace llvm |
| 63 | /// \endcode |
| 64 | class BinaryRef { |
| 65 | friend bool operator==(const BinaryRef &LHS, const BinaryRef &RHS); |
| 66 | |
| 67 | /// \brief Either raw binary data, or a string of hex bytes (must always |
| 68 | /// be an even number of characters). |
| 69 | ArrayRef<uint8_t> Data; |
| 70 | |
| 71 | /// \brief Discriminator between the two states of the `Data` member. |
| 72 | bool DataIsHexString = true; |
| 73 | |
| 74 | public: |
| 75 | BinaryRef() = default; |
| 76 | BinaryRef(ArrayRef<uint8_t> Data) : Data(Data), DataIsHexString(false) {} |
| 77 | BinaryRef(StringRef Data) |
| 78 | : Data(reinterpret_cast<const uint8_t *>(Data.data()), Data.size()) {} |
| 79 | |
| 80 | /// \brief The number of bytes that are represented by this BinaryRef. |
| 81 | /// This is the number of bytes that writeAsBinary() will write. |
| 82 | ArrayRef<uint8_t>::size_type binary_size() const { |
| 83 | if (DataIsHexString) |
| 84 | return Data.size() / 2; |
| 85 | return Data.size(); |
| 86 | } |
| 87 | |
| 88 | /// \brief Write the contents (regardless of whether it is binary or a |
| 89 | /// hex string) as binary to the given raw_ostream. |
| 90 | void writeAsBinary(raw_ostream &OS) const; |
| 91 | |
| 92 | /// \brief Write the contents (regardless of whether it is binary or a |
| 93 | /// hex string) as hex to the given raw_ostream. |
| 94 | /// |
| 95 | /// For example, a possible output could be `DEADBEEFCAFEBABE`. |
| 96 | void writeAsHex(raw_ostream &OS) const; |
| 97 | }; |
| 98 | |
| 99 | inline bool operator==(const BinaryRef &LHS, const BinaryRef &RHS) { |
| 100 | // Special case for default constructed BinaryRef. |
| 101 | if (LHS.Data.empty() && RHS.Data.empty()) |
| 102 | return true; |
| 103 | |
| 104 | return LHS.DataIsHexString == RHS.DataIsHexString && LHS.Data == RHS.Data; |
| 105 | } |
| 106 | |
| 107 | template <> struct ScalarTraits<BinaryRef> { |
| 108 | static void output(const BinaryRef &, void *, raw_ostream &); |
| 109 | static StringRef input(StringRef, void *, BinaryRef &); |
| 110 | static QuotingType mustQuote(StringRef S) { return needsQuotes(S); } |
| 111 | }; |
| 112 | |
| 113 | } // end namespace yaml |
| 114 | |
| 115 | } // end namespace llvm |
| 116 | |
| 117 | #endif // LLVM_OBJECTYAML_YAML_H |