llvm/llvm/include/llvm/Support/LEB128.h

//===- llvm/Support/LEB128.h - [SU]LEB128 utility functions -----*- 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
//
//===----------------------------------------------------------------------===//
//
// This file declares some utility functions for encoding SLEB128 and
// ULEB128 values.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_SUPPORT_LEB128_H
#define LLVM_SUPPORT_LEB128_H

#include "llvm/Support/raw_ostream.h"

namespace llvm {

/// Utility function to encode a SLEB128 value to an output stream. Returns
/// the length in bytes of the encoded value.
inline unsigned encodeSLEB128(int64_t Value, raw_ostream &OS,
                              unsigned PadTo = 0) { … }

/// Utility function to encode a SLEB128 value to a buffer. Returns
/// the length in bytes of the encoded value.
inline unsigned encodeSLEB128(int64_t Value, uint8_t *p, unsigned PadTo = 0) { … }

/// Utility function to encode a ULEB128 value to an output stream. Returns
/// the length in bytes of the encoded value.
inline unsigned encodeULEB128(uint64_t Value, raw_ostream &OS,
                              unsigned PadTo = 0) { … }

/// Utility function to encode a ULEB128 value to a buffer. Returns
/// the length in bytes of the encoded value.
inline unsigned encodeULEB128(uint64_t Value, uint8_t *p,
                              unsigned PadTo = 0) { … }

/// Utility function to decode a ULEB128 value.
///
/// If \p error is non-null, it will point to a static error message,
/// if an error occured. It will not be modified on success.
inline uint64_t decodeULEB128(const uint8_t *p, unsigned *n = nullptr,
                              const uint8_t *end = nullptr,
                              const char **error = nullptr) { … }

/// Utility function to decode a SLEB128 value.
///
/// If \p error is non-null, it will point to a static error message,
/// if an error occured. It will not be modified on success.
inline int64_t decodeSLEB128(const uint8_t *p, unsigned *n = nullptr,
                             const uint8_t *end = nullptr,
                             const char **error = nullptr) { … }

inline uint64_t decodeULEB128AndInc(const uint8_t *&p, const uint8_t *end,
                                    const char **error = nullptr) { … }

inline int64_t decodeSLEB128AndInc(const uint8_t *&p, const uint8_t *end,
                                   const char **error = nullptr) { … }

inline uint64_t decodeULEB128AndIncUnsafe(const uint8_t *&p) { … }

/// Utility function to get the size of the ULEB128-encoded value.
extern unsigned getULEB128Size(uint64_t Value);

/// Utility function to get the size of the SLEB128-encoded value.
extern unsigned getSLEB128Size(int64_t Value);

} // namespace llvm

#endif // LLVM_SUPPORT_LEB128_H