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//===-- DataEncoder.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 LLDB_UTILITY_DATAENCODER_H
#define LLDB_UTILITY_DATAENCODER_H
#if defined(__cplusplus)
#include "lldb/lldb-defines.h"
#include "lldb/lldb-enumerations.h"
#include "lldb/lldb-forward.h"
#include "lldb/lldb-types.h"
#include <stddef.h>
#include <stdint.h>
namespace lldb_private {
/// \class DataEncoder
///
/// An binary data encoding class.
///
/// DataEncoder is a class that can encode binary data (swapping if needed) to
/// a data buffer. The data buffer can be caller owned, or can be shared data
/// that can be shared between multiple DataEncoder or DataEncoder instances.
///
/// \see DataBuffer
class DataEncoder {
public:
/// Default constructor.
///
/// Initialize all members to a default empty state.
DataEncoder();
/// Construct with a buffer that is owned by the caller.
///
/// This constructor allows us to use data that is owned by the caller. The
/// data must stay around as long as this object is valid.
///
/// \param[in] data
/// A pointer to caller owned data.
///
/// \param[in] data_length
/// The length in bytes of \a data.
///
/// \param[in] byte_order
/// A byte order of the data that we are extracting from.
///
/// \param[in] addr_size
/// A new address byte size value.
DataEncoder(void *data, uint32_t data_length, lldb::ByteOrder byte_order,
uint8_t addr_size);
/// Construct with shared data.
///
/// Copies the data shared pointer which adds a reference to the contained
/// in \a data_sp. The shared data reference is reference counted to ensure
/// the data lives as long as anyone still has a valid shared pointer to the
/// data in \a data_sp.
///
/// \param[in] data_sp
/// A shared pointer to data.
///
/// \param[in] byte_order
/// A byte order of the data that we are extracting from.
///
/// \param[in] addr_size
/// A new address byte size value.
DataEncoder(const lldb::DataBufferSP &data_sp, lldb::ByteOrder byte_order,
uint8_t addr_size);
/// Destructor
///
/// If this object contains a valid shared data reference, the reference
/// count on the data will be decremented, and if zero, the data will be
/// freed.
~DataEncoder();
/// Clears the object state.
///
/// Clears the object contents back to a default invalid state, and release
/// any references to shared data that this object may contain.
void Clear();
/// Encode an unsigned integer of size \a byte_size to \a offset.
///
/// Encode a single integer value at \a offset and return the offset that
/// follows the newly encoded integer when the data is successfully encoded
/// into the existing data. There must be enough room in the data, else
/// UINT32_MAX will be returned to indicate that encoding failed.
///
/// \param[in] offset
/// The offset within the contained data at which to put the
/// encoded integer.
///
/// \param[in] byte_size
/// The size in byte of the integer to encode.
///
/// \param[in] value
/// The integer value to write. The least significant bytes of
/// the integer value will be written if the size is less than
/// 8 bytes.
///
/// \return
/// The next offset in the bytes of this data if the integer
/// was successfully encoded, UINT32_MAX if the encoding failed.
uint32_t PutUnsigned(uint32_t offset, uint32_t byte_size, uint64_t value);
/// Encode an arbitrary number of bytes.
///
/// \param[in] offset
/// The offset in bytes into the contained data at which to
/// start encoding.
///
/// \param[in] src
/// The buffer that contains the bytes to encode.
///
/// \param[in] src_len
/// The number of bytes to encode.
///
/// \return
/// The next valid offset within data if the put operation
/// was successful, else UINT32_MAX to indicate the put failed.
uint32_t PutData(uint32_t offset, const void *src, uint32_t src_len);
/// Encode an address in the existing buffer at \a offset bytes into the
/// buffer.
///
/// Encode a single address (honoring the m_addr_size member) to the data
/// and return the next offset where subsequent data would go. pointed to by
/// \a offset_ptr. The size of the extracted address comes from the \a
/// m_addr_size member variable and should be set correctly prior to
/// extracting any address values.
///
/// \param[in] offset
/// The offset where to encode the address.
///
/// \param[in] addr
/// The address to encode.
///
/// \return
/// The next valid offset within data if the put operation
/// was successful, else UINT32_MAX to indicate the put failed.
uint32_t PutAddress(uint32_t offset, lldb::addr_t addr);
/// Put a C string to \a offset.
///
/// Encodes a C string into the existing data including the terminating
///
/// \param[in] offset
/// The offset where to encode the string.
///
/// \param[in] cstr
/// The string to encode.
///
/// \return
/// A pointer to the C string value in the data. If the offset
/// pointed to by \a offset_ptr is out of bounds, or if the
/// offset plus the length of the C string is out of bounds,
/// NULL will be returned.
uint32_t PutCString(uint32_t offset, const char *cstr);
private:
uint32_t PutU8(uint32_t offset, uint8_t value);
uint32_t PutU16(uint32_t offset, uint16_t value);
uint32_t PutU32(uint32_t offset, uint32_t value);
uint32_t PutU64(uint32_t offset, uint64_t value);
uint32_t BytesLeft(uint32_t offset) const {
const uint32_t size = GetByteSize();
if (size > offset)
return size - offset;
return 0;
}
/// Test the availability of \a length bytes of data from \a offset.
///
/// \return
/// \b true if \a offset is a valid offset and there are \a
/// length bytes available at that offset, \b false otherwise.
bool ValidOffsetForDataOfSize(uint32_t offset, uint32_t length) const {
return length <= BytesLeft(offset);
}
/// Adopt a subset of shared data in \a data_sp.
///
/// Copies the data shared pointer which adds a reference to the contained
/// in \a data_sp. The shared data reference is reference counted to ensure
/// the data lives as long as anyone still has a valid shared pointer to the
/// data in \a data_sp. The byte order and address byte size settings remain
/// the same. If \a offset is not a valid offset in \a data_sp, then no
/// reference to the shared data will be added. If there are not \a length
/// bytes available in \a data starting at \a offset, the length will be
/// truncated to contains as many bytes as possible.
///
/// \param[in] data_sp
/// A shared pointer to data.
///
/// \param[in] offset
/// The offset into \a data_sp at which the subset starts.
///
/// \param[in] length
/// The length in bytes of the subset of \a data_sp.
///
/// \return
/// The number of bytes that this object now contains.
uint32_t SetData(const lldb::DataBufferSP &data_sp, uint32_t offset = 0,
uint32_t length = UINT32_MAX);
/// Test the validity of \a offset.
///
/// \return
/// \b true if \a offset is a valid offset into the data in this
/// object, \b false otherwise.
bool ValidOffset(uint32_t offset) const { return offset < GetByteSize(); }
/// Get the number of bytes contained in this object.
///
/// \return
/// The total number of bytes of data this object refers to.
size_t GetByteSize() const { return m_end - m_start; }
/// A pointer to the first byte of data.
uint8_t *m_start;
/// A pointer to the byte that is past the end of the data.
uint8_t *m_end;
/// The byte order of the data we are extracting from.
lldb::ByteOrder m_byte_order;
/// The address size to use when extracting pointers or
/// addresses
uint8_t m_addr_size;
/// The shared pointer to data that can
/// be shared among multiple instances
mutable lldb::DataBufferSP m_data_sp;
DataEncoder(const DataEncoder &) = delete;
const DataEncoder &operator=(const DataEncoder &) = delete;
};
} // namespace lldb_private
#endif // #if defined (__cplusplus)
#endif // LLDB_UTILITY_DATAENCODER_H