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//===- YAML.h ---------------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_OBJECTYAML_YAML_H
#define LLVM_OBJECTYAML_YAML_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/YAMLTraits.h"
#include <cstdint>
namespace llvm {
class raw_ostream;
namespace yaml {
/// Specialized YAMLIO scalar type for representing a binary blob.
///
/// A typical use case would be to represent the content of a section in a
/// binary file.
/// This class has custom YAMLIO traits for convenient reading and writing.
/// It renders as a string of hex digits in a YAML file.
/// For example, it might render as `DEADBEEFCAFEBABE` (YAML does not
/// require the quotation marks, so for simplicity when outputting they are
/// omitted).
/// When reading, any string whose content is an even number of hex digits
/// will be accepted.
/// For example, all of the following are acceptable:
/// `DEADBEEF`, `"DeADbEeF"`, `"\x44EADBEEF"` (Note: '\x44' == 'D')
///
/// A significant advantage of using this class is that it never allocates
/// temporary strings or buffers for any of its functionality.
///
/// Example:
///
/// The YAML mapping:
/// \code
/// Foo: DEADBEEFCAFEBABE
/// \endcode
///
/// Could be modeled in YAMLIO by the struct:
/// \code
/// struct FooHolder {
/// BinaryRef Foo;
/// };
/// namespace llvm {
/// namespace yaml {
/// template <>
/// struct MappingTraits<FooHolder> {
/// static void mapping(IO &IO, FooHolder &FH) {
/// IO.mapRequired("Foo", FH.Foo);
/// }
/// };
/// } // end namespace yaml
/// } // end namespace llvm
/// \endcode
class BinaryRef {
friend bool operator==(const BinaryRef &LHS, const BinaryRef &RHS);
/// Either raw binary data, or a string of hex bytes (must always
/// be an even number of characters).
ArrayRef<uint8_t> Data;
/// Discriminator between the two states of the `Data` member.
bool DataIsHexString = true;
public:
BinaryRef() = default;
BinaryRef(ArrayRef<uint8_t> Data) : Data(Data), DataIsHexString(false) {}
BinaryRef(StringRef Data) : Data(arrayRefFromStringRef(Data)) {}
/// The number of bytes that are represented by this BinaryRef.
/// This is the number of bytes that writeAsBinary() will write.
ArrayRef<uint8_t>::size_type binary_size() const {
if (DataIsHexString)
return Data.size() / 2;
return Data.size();
}
/// Write the contents (regardless of whether it is binary or a
/// hex string) as binary to the given raw_ostream.
/// N can be used to specify the maximum number of bytes.
void writeAsBinary(raw_ostream &OS, uint64_t N = UINT64_MAX) const;
/// Write the contents (regardless of whether it is binary or a
/// hex string) as hex to the given raw_ostream.
///
/// For example, a possible output could be `DEADBEEFCAFEBABE`.
void writeAsHex(raw_ostream &OS) const;
};
inline bool operator==(const BinaryRef &LHS, const BinaryRef &RHS) {
// Special case for default constructed BinaryRef.
if (LHS.Data.empty() && RHS.Data.empty())
return true;
return LHS.DataIsHexString == RHS.DataIsHexString && LHS.Data == RHS.Data;
}
template <> struct ScalarTraits<BinaryRef> {
static void output(const BinaryRef &, void *, raw_ostream &);
static StringRef input(StringRef, void *, BinaryRef &);
static QuotingType mustQuote(StringRef S) { return needsQuotes(S); }
};
} // end namespace yaml
} // end namespace llvm
#endif // LLVM_OBJECTYAML_YAML_H
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