1 files changed, 235 insertions, 0 deletions
diff --git a/lldb/source/Utility/DataEncoder.cpp b/lldb/source/Utility/DataEncoder.cpp
new file mode 100644
index 000000000000..13c505e34e82
--- /dev/null
+++ b/lldb/source/Utility/DataEncoder.cpp
@@ -0,0 +1,235 @@
+//===-- DataEncoder.cpp -----------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#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 "llvm/Support/MathExtras.h"
+
+#include <cassert>
+#include <cstddef>
+
+#include <string.h>
+
+using namespace lldb;
+using namespace lldb_private;
+using namespace llvm::support::endian;
+
+// Default constructor.
+DataEncoder::DataEncoder()
+    : m_start(nullptr), m_end(nullptr),
+      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() {
+  SetData(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 *);
+  m_data_sp.reset();
+}
+
+// If this object contains shared data, this function returns the offset into
+// that shared data. Else zero is returned.
+size_t DataEncoder::GetSharedDataOffset() const {
+  if (m_start != nullptr) {
+    const DataBuffer *data = m_data_sp.get();
+    if (data != nullptr) {
+      const uint8_t *data_bytes = data->GetBytes();
+      if (data_bytes != nullptr) {
+        assert(m_start >= data_bytes);
+        return m_start - data_bytes;
+      }
+    }
+  }
+  return 0;
+}
+
+// Set the data with which this object will extract from to data starting at
+// BYTES and set the length of the data to LENGTH bytes long. The data is
+// externally owned must be around at least as long as this object points to
+// the data. No copy of the data is made, this object just refers to this data
+// and can extract from it. If this object refers to any shared data upon
+// entry, the reference to that data will be released. Is SWAP is set to true,
+// any data extracted will be endian swapped.
+uint32_t DataEncoder::SetData(void *bytes, uint32_t length, ByteOrder endian) {
+  m_byte_order = endian;
+  m_data_sp.reset();
+  if (bytes == nullptr || length == 0) {
+    m_start = nullptr;
+    m_end = nullptr;
+  } else {
+    m_start = static_cast<uint8_t *>(bytes);
+    m_end = m_start + length;
+  }
+  return GetByteSize();
+}
+
+// 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
+        else
+          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)
+    m_data_sp.reset();
+
+  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);
+    else
+      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);
+    else
+      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);
+    else
+      write64le(m_start + offset, value);
+
+    return offset + sizeof(value);
+  }
+  return UINT32_MAX;
+}
+
+// Extract a single integer value from the data and update the offset pointed
+// to by "offset_ptr". The size of the extracted integer is specified by the
+// "byte_size" argument. "byte_size" should have a value >= 1 and <= 8 since
+// the return value is only 64 bits wide. Any "byte_size" values less than 1 or
+// greater than 8 will result in nothing being extracted, and zero being
+// returned.
+//
+// RETURNS the integer value that was extracted, or zero on failure.
+uint32_t DataEncoder::PutMaxU64(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);
+  default:
+    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 PutMaxU64(offset, GetAddressByteSize(), addr);
+}
+
+uint32_t DataEncoder::PutCString(uint32_t offset, const char *cstr) {
+  if (cstr != nullptr)
+    return PutData(offset, cstr, strlen(cstr) + 1);
+  return UINT32_MAX;
+}