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//===-- DataEncoder.cpp ---------------------------------------------------===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "lldb/Utility/DataEncoder.h"
#include "lldb/Utility/DataBuffer.h"
#include "lldb/Utility/Endian.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/ErrorHandling.h"
#include <cstddef>
#include <cstring>
using namespace lldb;
using namespace lldb_private;
using namespace llvm::support::endian;
// Default constructor.
: m_byte_order(endian::InlHostByteOrder()), m_addr_size(sizeof(void *)),
m_data_sp() {}
// This constructor allows us to use data that is owned by someone else. The
// data must stay around as long as this object is valid.
DataEncoder::DataEncoder(void *data, uint32_t length, ByteOrder endian,
uint8_t addr_size)
: m_start(static_cast<uint8_t *>(data)),
m_end(static_cast<uint8_t *>(data) + length), m_byte_order(endian),
m_addr_size(addr_size), m_data_sp() {}
// Make a shared pointer reference to the shared data in "data_sp" and set the
// endian swapping setting to "swap", and the address size to "addr_size". The
// shared data reference will ensure the data lives as long as any DataEncoder
// objects exist that have a reference to this data.
DataEncoder::DataEncoder(const DataBufferSP &data_sp, ByteOrder endian,
uint8_t addr_size)
: m_start(nullptr), m_end(nullptr), m_byte_order(endian),
m_addr_size(addr_size), m_data_sp() {
DataEncoder::~DataEncoder() = default;
// Clears the object contents back to a default invalid state, and release any
// references to shared data that this object may contain.
void DataEncoder::Clear() {
m_start = nullptr;
m_end = nullptr;
m_byte_order = endian::InlHostByteOrder();
m_addr_size = sizeof(void *);
// Assign the data for this object to be a subrange of the shared data in
// "data_sp" starting "data_offset" bytes into "data_sp" and ending
// "data_length" bytes later. If "data_offset" is not a valid offset into
// "data_sp", then this object will contain no bytes. If "data_offset" is
// within "data_sp" yet "data_length" is too large, the length will be capped
// at the number of bytes remaining in "data_sp". A ref counted pointer to the
// data in "data_sp" will be made in this object IF the number of bytes this
// object refers to in greater than zero (if at least one byte was available
// starting at "data_offset") to ensure the data stays around as long as it is
// needed. The address size and endian swap settings will remain unchanged from
// their current settings.
uint32_t DataEncoder::SetData(const DataBufferSP &data_sp, uint32_t data_offset,
uint32_t data_length) {
m_start = m_end = nullptr;
if (data_length > 0) {
m_data_sp = data_sp;
if (data_sp) {
const size_t data_size = data_sp->GetByteSize();
if (data_offset < data_size) {
m_start = data_sp->GetBytes() + data_offset;
const size_t bytes_left = data_size - data_offset;
// Cap the length of we asked for too many
if (data_length <= bytes_left)
m_end = m_start + data_length; // We got all the bytes we wanted
m_end = m_start + bytes_left; // Not all the bytes requested were
// available in the shared data
uint32_t new_size = GetByteSize();
// Don't hold a shared pointer to the data buffer if we don't share any valid
// bytes in the shared buffer.
if (new_size == 0)
return new_size;
// Extract a single unsigned char from the binary data and update the offset
// pointed to by "offset_ptr".
// RETURNS the byte that was extracted, or zero on failure.
uint32_t DataEncoder::PutU8(uint32_t offset, uint8_t value) {
if (ValidOffset(offset)) {
m_start[offset] = value;
return offset + 1;
return UINT32_MAX;
uint32_t DataEncoder::PutU16(uint32_t offset, uint16_t value) {
if (ValidOffsetForDataOfSize(offset, sizeof(value))) {
if (m_byte_order != endian::InlHostByteOrder())
write16be(m_start + offset, value);
write16le(m_start + offset, value);
return offset + sizeof(value);
return UINT32_MAX;
uint32_t DataEncoder::PutU32(uint32_t offset, uint32_t value) {
if (ValidOffsetForDataOfSize(offset, sizeof(value))) {
if (m_byte_order != endian::InlHostByteOrder())
write32be(m_start + offset, value);
write32le(m_start + offset, value);
return offset + sizeof(value);
return UINT32_MAX;
uint32_t DataEncoder::PutU64(uint32_t offset, uint64_t value) {
if (ValidOffsetForDataOfSize(offset, sizeof(value))) {
if (m_byte_order != endian::InlHostByteOrder())
write64be(m_start + offset, value);
write64le(m_start + offset, value);
return offset + sizeof(value);
return UINT32_MAX;
uint32_t DataEncoder::PutUnsigned(uint32_t offset, uint32_t byte_size,
uint64_t value) {
switch (byte_size) {
case 1:
return PutU8(offset, value);
case 2:
return PutU16(offset, value);
case 4:
return PutU32(offset, value);
case 8:
return PutU64(offset, value);
llvm_unreachable("GetMax64 unhandled case!");
return UINT32_MAX;
uint32_t DataEncoder::PutData(uint32_t offset, const void *src,
uint32_t src_len) {
if (src == nullptr || src_len == 0)
return offset;
if (ValidOffsetForDataOfSize(offset, src_len)) {
memcpy(m_start + offset, src, src_len);
return offset + src_len;
return UINT32_MAX;
uint32_t DataEncoder::PutAddress(uint32_t offset, lldb::addr_t addr) {
return PutUnsigned(offset, m_addr_size, addr);
uint32_t DataEncoder::PutCString(uint32_t offset, const char *cstr) {
if (cstr != nullptr)
return PutData(offset, cstr, strlen(cstr) + 1);
return UINT32_MAX;