root/base/pickle.cc

DEFINITIONS

1. read_end_ptr_
2. ReadBuiltinType
3. GetReadPointerAndAdvance
4. GetReadPointerAndAdvance
5. GetReadPointerAndAdvance
6. ReadBool
7. ReadInt
8. ReadLong
9. ReadUInt16
10. ReadUInt32
11. ReadInt64
12. ReadUInt64
13. ReadFloat
14. ReadString
15. ReadWString
16. ReadString16
17. ReadData
18. ReadBytes
19. write_offset_
20. write_offset_
21. write_offset_
22. write_offset_
23. WriteString
24. WriteWString
25. WriteString16
26. WriteData
27. WriteBytes
28. Reserve
29. Resize
30. FindNext
31. WriteBytesStatic
32. WriteBytesCommon

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/pickle.h"

#include <stdlib.h>

#include <algorithm>  // for max()

//------------------------------------------------------------------------------

using base::char16;
using base::string16;

// static
const int Pickle::kPayloadUnit = 64;

static const size_t kCapacityReadOnly = static_cast<size_t>(-1);

PickleIterator::PickleIterator(const Pickle& pickle)
    : read_ptr_(pickle.payload()),
      read_end_ptr_(pickle.end_of_payload()) {
}

template <typename Type>
inline bool PickleIterator::ReadBuiltinType(Type* result) {
  const char* read_from = GetReadPointerAndAdvance<Type>();
  if (!read_from)
    return false;
  if (sizeof(Type) > sizeof(uint32))
    memcpy(result, read_from, sizeof(*result));
  else
    *result = *reinterpret_cast<const Type*>(read_from);
  return true;
}

template<typename Type>
inline const char* PickleIterator::GetReadPointerAndAdvance() {
  const char* current_read_ptr = read_ptr_;
  if (read_ptr_ + sizeof(Type) > read_end_ptr_)
    return NULL;
  if (sizeof(Type) < sizeof(uint32))
    read_ptr_ += AlignInt(sizeof(Type), sizeof(uint32));
  else
    read_ptr_ += sizeof(Type);
  return current_read_ptr;
}

const char* PickleIterator::GetReadPointerAndAdvance(int num_bytes) {
  if (num_bytes < 0 || read_end_ptr_ - read_ptr_ < num_bytes)
    return NULL;
  const char* current_read_ptr = read_ptr_;
  read_ptr_ += AlignInt(num_bytes, sizeof(uint32));
  return current_read_ptr;
}

inline const char* PickleIterator::GetReadPointerAndAdvance(int num_elements,
                                                          size_t size_element) {
  // Check for int32 overflow.
  int64 num_bytes = static_cast<int64>(num_elements) * size_element;
  int num_bytes32 = static_cast<int>(num_bytes);
  if (num_bytes != static_cast<int64>(num_bytes32))
    return NULL;
  return GetReadPointerAndAdvance(num_bytes32);
}

bool PickleIterator::ReadBool(bool* result) {
  return ReadBuiltinType(result);
}

bool PickleIterator::ReadInt(int* result) {
  return ReadBuiltinType(result);
}

bool PickleIterator::ReadLong(long* result) {
  return ReadBuiltinType(result);
}

bool PickleIterator::ReadUInt16(uint16* result) {
  return ReadBuiltinType(result);
}

bool PickleIterator::ReadUInt32(uint32* result) {
  return ReadBuiltinType(result);
}

bool PickleIterator::ReadInt64(int64* result) {
  return ReadBuiltinType(result);
}

bool PickleIterator::ReadUInt64(uint64* result) {
  return ReadBuiltinType(result);
}

bool PickleIterator::ReadFloat(float* result) {
  // crbug.com/315213
  // The source data may not be properly aligned, and unaligned float reads
  // cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
  // into the result.
  const char* read_from = GetReadPointerAndAdvance<float>();
  if (!read_from)
    return false;
  memcpy(result, read_from, sizeof(*result));
  return true;
}

bool PickleIterator::ReadString(std::string* result) {
  int len;
  if (!ReadInt(&len))
    return false;
  const char* read_from = GetReadPointerAndAdvance(len);
  if (!read_from)
    return false;

  result->assign(read_from, len);
  return true;
}

bool PickleIterator::ReadWString(std::wstring* result) {
  int len;
  if (!ReadInt(&len))
    return false;
  const char* read_from = GetReadPointerAndAdvance(len, sizeof(wchar_t));
  if (!read_from)
    return false;

  result->assign(reinterpret_cast<const wchar_t*>(read_from), len);
  return true;
}

bool PickleIterator::ReadString16(string16* result) {
  int len;
  if (!ReadInt(&len))
    return false;
  const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16));
  if (!read_from)
    return false;

  result->assign(reinterpret_cast<const char16*>(read_from), len);
  return true;
}

bool PickleIterator::ReadData(const char** data, int* length) {
  *length = 0;
  *data = 0;

  if (!ReadInt(length))
    return false;

  return ReadBytes(data, *length);
}

bool PickleIterator::ReadBytes(const char** data, int length) {
  const char* read_from = GetReadPointerAndAdvance(length);
  if (!read_from)
    return false;
  *data = read_from;
  return true;
}

// Payload is uint32 aligned.

Pickle::Pickle()
    : header_(NULL),
      header_size_(sizeof(Header)),
      capacity_after_header_(0),
      write_offset_(0) {
  Resize(kPayloadUnit);
  header_->payload_size = 0;
}

Pickle::Pickle(int header_size)
    : header_(NULL),
      header_size_(AlignInt(header_size, sizeof(uint32))),
      capacity_after_header_(0),
      write_offset_(0) {
  DCHECK_GE(static_cast<size_t>(header_size), sizeof(Header));
  DCHECK_LE(header_size, kPayloadUnit);
  Resize(kPayloadUnit);
  header_->payload_size = 0;
}

Pickle::Pickle(const char* data, int data_len)
    : header_(reinterpret_cast<Header*>(const_cast<char*>(data))),
      header_size_(0),
      capacity_after_header_(kCapacityReadOnly),
      write_offset_(0) {
  if (data_len >= static_cast<int>(sizeof(Header)))
    header_size_ = data_len - header_->payload_size;

  if (header_size_ > static_cast<unsigned int>(data_len))
    header_size_ = 0;

  if (header_size_ != AlignInt(header_size_, sizeof(uint32)))
    header_size_ = 0;

  // If there is anything wrong with the data, we're not going to use it.
  if (!header_size_)
    header_ = NULL;
}

Pickle::Pickle(const Pickle& other)
    : header_(NULL),
      header_size_(other.header_size_),
      capacity_after_header_(0),
      write_offset_(other.write_offset_) {
  size_t payload_size = header_size_ + other.header_->payload_size;
  Resize(payload_size);
  memcpy(header_, other.header_, payload_size);
}

Pickle::~Pickle() {
  if (capacity_after_header_ != kCapacityReadOnly)
    free(header_);
}

Pickle& Pickle::operator=(const Pickle& other) {
  if (this == &other) {
    NOTREACHED();
    return *this;
  }
  if (capacity_after_header_ == kCapacityReadOnly) {
    header_ = NULL;
    capacity_after_header_ = 0;
  }
  if (header_size_ != other.header_size_) {
    free(header_);
    header_ = NULL;
    header_size_ = other.header_size_;
  }
  Resize(other.header_->payload_size);
  memcpy(header_, other.header_,
         other.header_size_ + other.header_->payload_size);
  write_offset_ = other.write_offset_;
  return *this;
}

bool Pickle::WriteString(const std::string& value) {
  if (!WriteInt(static_cast<int>(value.size())))
    return false;

  return WriteBytes(value.data(), static_cast<int>(value.size()));
}

bool Pickle::WriteWString(const std::wstring& value) {
  if (!WriteInt(static_cast<int>(value.size())))
    return false;

  return WriteBytes(value.data(),
                    static_cast<int>(value.size() * sizeof(wchar_t)));
}

bool Pickle::WriteString16(const string16& value) {
  if (!WriteInt(static_cast<int>(value.size())))
    return false;

  return WriteBytes(value.data(),
                    static_cast<int>(value.size()) * sizeof(char16));
}

bool Pickle::WriteData(const char* data, int length) {
  return length >= 0 && WriteInt(length) && WriteBytes(data, length);
}

bool Pickle::WriteBytes(const void* data, int length) {
  WriteBytesCommon(data, length);
  return true;
}

void Pickle::Reserve(size_t length) {
  size_t data_len = AlignInt(length, sizeof(uint32));
  DCHECK_GE(data_len, length);
#ifdef ARCH_CPU_64_BITS
  DCHECK_LE(data_len, kuint32max);
#endif
  DCHECK_LE(write_offset_, kuint32max - data_len);
  size_t new_size = write_offset_ + data_len;
  if (new_size > capacity_after_header_)
    Resize(capacity_after_header_ * 2 + new_size);
}

void Pickle::Resize(size_t new_capacity) {
  new_capacity = AlignInt(new_capacity, kPayloadUnit);

  CHECK_NE(capacity_after_header_, kCapacityReadOnly);
  void* p = realloc(header_, header_size_ + new_capacity);
  CHECK(p);
  header_ = reinterpret_cast<Header*>(p);
  capacity_after_header_ = new_capacity;
}

// static
const char* Pickle::FindNext(size_t header_size,
                             const char* start,
                             const char* end) {
  DCHECK_EQ(header_size, AlignInt(header_size, sizeof(uint32)));
  DCHECK_LE(header_size, static_cast<size_t>(kPayloadUnit));

  size_t length = static_cast<size_t>(end - start);
  if (length < sizeof(Header))
    return NULL;

  const Header* hdr = reinterpret_cast<const Header*>(start);
  if (length < header_size || length - header_size < hdr->payload_size)
    return NULL;
  return start + header_size + hdr->payload_size;
}

template <size_t length> void Pickle::WriteBytesStatic(const void* data) {
  WriteBytesCommon(data, length);
}

template void Pickle::WriteBytesStatic<2>(const void* data);
template void Pickle::WriteBytesStatic<4>(const void* data);
template void Pickle::WriteBytesStatic<8>(const void* data);

inline void Pickle::WriteBytesCommon(const void* data, size_t length) {
  DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
      << "oops: pickle is readonly";
  size_t data_len = AlignInt(length, sizeof(uint32));
  DCHECK_GE(data_len, length);
#ifdef ARCH_CPU_64_BITS
  DCHECK_LE(data_len, kuint32max);
#endif
  DCHECK_LE(write_offset_, kuint32max - data_len);
  size_t new_size = write_offset_ + data_len;
  if (new_size > capacity_after_header_) {
    Resize(std::max(capacity_after_header_ * 2, new_size));
  }

  char* write = mutable_payload() + write_offset_;
  memcpy(write, data, length);
  memset(write + length, 0, data_len - length);
  header_->payload_size = static_cast<uint32>(write_offset_ + length);
  write_offset_ = new_size;
}