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Chromium pickle
//https://code.google.com/p/chromium/codesearch#chromium/src/base/pickle.cc
// 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)
: payload_(pickle.payload()),
read_index_(0),
end_index_(pickle.payload_size()) {
}
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;
}
inline void PickleIterator::Advance(size_t size) {
size_t aligned_size = AlignInt(size, sizeof(uint32_t));
if (end_index_ - read_index_ < aligned_size) {
read_index_ = end_index_;
} else {
read_index_ += aligned_size;
}
}
template<typename Type>
inline const char* PickleIterator::GetReadPointerAndAdvance() {
if (sizeof(Type) > end_index_ - read_index_) {
read_index_ = end_index_;
return NULL;
}
const char* current_read_ptr = payload_ + read_index_;
Advance(sizeof(Type));
return current_read_ptr;
}
const char* PickleIterator::GetReadPointerAndAdvance(int num_bytes) {
if (num_bytes < 0 ||
end_index_ - read_index_ < static_cast<size_t>(num_bytes)) {
read_index_ = end_index_;
return NULL;
}
const char* current_read_ptr = payload_ + read_index_;
Advance(num_bytes);
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::ReadSizeT(size_t* result) {
// Always read size_t as a 64-bit value to ensure compatibility between 32-bit
// and 64-bit processes.
uint64 result_uint64 = 0;
bool success = ReadBuiltinType(&result_uint64);
*result = static_cast<size_t>(result_uint64);
// Fail if the cast above truncates the value.
return success && (*result == result_uint64);
}
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::ReadDouble(double* result) {
// crbug.com/315213
// The source data may not be properly aligned, and unaligned double reads
// cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
// into the result.
const char* read_from = GetReadPointerAndAdvance<double>();
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::ReadStringPiece(base::StringPiece* result) {
int len;
if (!ReadInt(&len))
return false;
const char* read_from = GetReadPointerAndAdvance(len);
if (!read_from)
return false;
*result = base::StringPiece(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::ReadStringPiece16(base::StringPiece16* result) {
int len;
if (!ReadInt(&len))
return false;
const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16));
if (!read_from)
return false;
*result = base::StringPiece16(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 base::StringPiece& value) {
if (!WriteInt(static_cast<int>(value.size())))
return false;
return WriteBytes(value.data(), static_cast<int>(value.size()));
}
bool Pickle::WriteString16(const base::StringPiece16& 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";
MSAN_CHECK_MEM_IS_INITIALIZED(data, 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(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>(new_size);
write_offset_ = new_size;
}
//https://code.google.com/p/chromium/codesearch#chromium/src/base/pickle.h
// 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.
#ifndef BASE_PICKLE_H__
#define BASE_PICKLE_H__
#include <string>
#include "base/base_export.h"
#include "base/basictypes.h"
#include "base/compiler_specific.h"
#include "base/gtest_prod_util.h"
#include "base/logging.h"
#include "base/strings/string16.h"
#include "base/strings/string_piece.h"
class Pickle;
// PickleIterator reads data from a Pickle. The Pickle object must remain valid
// while the PickleIterator object is in use.
class BASE_EXPORT PickleIterator {
public:
PickleIterator() : payload_(NULL), read_index_(0), end_index_(0) {}
explicit PickleIterator(const Pickle& pickle);
// Methods for reading the payload of the Pickle. To read from the start of
// the Pickle, create a PickleIterator from a Pickle. If successful, these
// methods return true. Otherwise, false is returned to indicate that the
// result could not be extracted. It is not possible to read from the iterator
// after that.
bool ReadBool(bool* result) WARN_UNUSED_RESULT;
bool ReadInt(int* result) WARN_UNUSED_RESULT;
bool ReadLong(long* result) WARN_UNUSED_RESULT;
bool ReadUInt16(uint16* result) WARN_UNUSED_RESULT;
bool ReadUInt32(uint32* result) WARN_UNUSED_RESULT;
bool ReadInt64(int64* result) WARN_UNUSED_RESULT;
bool ReadUInt64(uint64* result) WARN_UNUSED_RESULT;
bool ReadSizeT(size_t* result) WARN_UNUSED_RESULT;
bool ReadFloat(float* result) WARN_UNUSED_RESULT;
bool ReadDouble(double* result) WARN_UNUSED_RESULT;
bool ReadString(std::string* result) WARN_UNUSED_RESULT;
// The StringPiece data will only be valid for the lifetime of the message.
bool ReadStringPiece(base::StringPiece* result) WARN_UNUSED_RESULT;
bool ReadString16(base::string16* result) WARN_UNUSED_RESULT;
// The StringPiece16 data will only be valid for the lifetime of the message.
bool ReadStringPiece16(base::StringPiece16* result) WARN_UNUSED_RESULT;
// A pointer to the data will be placed in |*data|, and the length will be
// placed in |*length|. The pointer placed into |*data| points into the
// message's buffer so it will be scoped to the lifetime of the message (or
// until the message data is mutated). Do not keep the pointer around!
bool ReadData(const char** data, int* length) WARN_UNUSED_RESULT;
// A pointer to the data will be placed in |*data|. The caller specifies the
// number of bytes to read, and ReadBytes will validate this length. The
// pointer placed into |*data| points into the message's buffer so it will be
// scoped to the lifetime of the message (or until the message data is
// mutated). Do not keep the pointer around!
bool ReadBytes(const char** data, int length) WARN_UNUSED_RESULT;
// A safer version of ReadInt() that checks for the result not being negative.
// Use it for reading the object sizes.
bool ReadLength(int* result) WARN_UNUSED_RESULT {
return ReadInt(result) && *result >= 0;
}
// Skips bytes in the read buffer and returns true if there are at least
// num_bytes available. Otherwise, does nothing and returns false.
bool SkipBytes(int num_bytes) WARN_UNUSED_RESULT {
return !!GetReadPointerAndAdvance(num_bytes);
}
private:
// Aligns 'i' by rounding it up to the next multiple of 'alignment'.
static size_t AlignInt(size_t i, int alignment) {
return i + (alignment - (i % alignment)) % alignment;
}
// Read Type from Pickle.
template <typename Type>
bool ReadBuiltinType(Type* result);
// Advance read_index_ but do not allow it to exceed end_index_.
// Keeps read_index_ aligned.
void Advance(size_t size);
// Get read pointer for Type and advance read pointer.
template<typename Type>
const char* GetReadPointerAndAdvance();
// Get read pointer for |num_bytes| and advance read pointer. This method
// checks num_bytes for negativity and wrapping.
const char* GetReadPointerAndAdvance(int num_bytes);
// Get read pointer for (num_elements * size_element) bytes and advance read
// pointer. This method checks for int overflow, negativity and wrapping.
const char* GetReadPointerAndAdvance(int num_elements,
size_t size_element);
const char* payload_; // Start of our pickle's payload.
size_t read_index_; // Offset of the next readable byte in payload.
size_t end_index_; // Payload size.
FRIEND_TEST_ALL_PREFIXES(PickleTest, GetReadPointerAndAdvance);
};
// This class provides facilities for basic binary value packing and unpacking.
//
// The Pickle class supports appending primitive values (ints, strings, etc.)
// to a pickle instance. The Pickle instance grows its internal memory buffer
// dynamically to hold the sequence of primitive values. The internal memory
// buffer is exposed as the "data" of the Pickle. This "data" can be passed
// to a Pickle object to initialize it for reading.
//
// When reading from a Pickle object, it is important for the consumer to know
// what value types to read and in what order to read them as the Pickle does
// not keep track of the type of data written to it.
//
// The Pickle's data has a header which contains the size of the Pickle's
// payload. It can optionally support additional space in the header. That
// space is controlled by the header_size parameter passed to the Pickle
// constructor.
//
class BASE_EXPORT Pickle {
public:
// Initialize a Pickle object using the default header size.
Pickle();
// Initialize a Pickle object with the specified header size in bytes, which
// must be greater-than-or-equal-to sizeof(Pickle::Header). The header size
// will be rounded up to ensure that the header size is 32bit-aligned.
explicit Pickle(int header_size);
// Initializes a Pickle from a const block of data. The data is not copied;
// instead the data is merely referenced by this Pickle. Only const methods
// should be used on the Pickle when initialized this way. The header
// padding size is deduced from the data length.
Pickle(const char* data, int data_len);
// Initializes a Pickle as a deep copy of another Pickle.
Pickle(const Pickle& other);
// Note: There are no virtual methods in this class. This destructor is
// virtual as an element of defensive coding. Other classes have derived from
// this class, and there is a *chance* that they will cast into this base
// class before destruction. At least one such class does have a virtual
// destructor, suggesting at least some need to call more derived destructors.
virtual ~Pickle();
// Performs a deep copy.
Pickle& operator=(const Pickle& other);
// Returns the size of the Pickle's data.
size_t size() const { return header_size_ + header_->payload_size; }
// Returns the data for this Pickle.
const void* data() const { return header_; }
// Methods for adding to the payload of the Pickle. These values are
// appended to the end of the Pickle's payload. When reading values from a
// Pickle, it is important to read them in the order in which they were added
// to the Pickle.
bool WriteBool(bool value) {
return WriteInt(value ? 1 : 0);
}
bool WriteInt(int value) {
return WritePOD(value);
}
// WARNING: DO NOT USE THIS METHOD IF PICKLES ARE PERSISTED IN ANY WAY.
// It will write whatever a "long" is on this architecture. On 32-bit
// platforms, it is 32 bits. On 64-bit platforms, it is 64 bits. If persisted
// pickles are still around after upgrading to 64-bit, or if they are copied
// between dissimilar systems, YOUR PICKLES WILL HAVE GONE BAD.
bool WriteLongUsingDangerousNonPortableLessPersistableForm(long value) {
return WritePOD(value);
}
bool WriteUInt16(uint16 value) {
return WritePOD(value);
}
bool WriteUInt32(uint32 value) {
return WritePOD(value);
}
bool WriteInt64(int64 value) {
return WritePOD(value);
}
bool WriteUInt64(uint64 value) {
return WritePOD(value);
}
bool WriteSizeT(size_t value) {
// Always write size_t as a 64-bit value to ensure compatibility between
// 32-bit and 64-bit processes.
return WritePOD(static_cast<uint64>(value));
}
bool WriteFloat(float value) {
return WritePOD(value);
}
bool WriteDouble(double value) {
return WritePOD(value);
}
bool WriteString(const base::StringPiece& value);
bool WriteString16(const base::StringPiece16& value);
// "Data" is a blob with a length. When you read it out you will be given the
// length. See also WriteBytes.
bool WriteData(const char* data, int length);
// "Bytes" is a blob with no length. The caller must specify the length both
// when reading and writing. It is normally used to serialize PoD types of a
// known size. See also WriteData.
bool WriteBytes(const void* data, int length);
// Reserves space for upcoming writes when multiple writes will be made and
// their sizes are computed in advance. It can be significantly faster to call
// Reserve() before calling WriteFoo() multiple times.
void Reserve(size_t additional_capacity);
// Payload follows after allocation of Header (header size is customizable).
struct Header {
uint32 payload_size; // Specifies the size of the payload.
};
// Returns the header, cast to a user-specified type T. The type T must be a
// subclass of Header and its size must correspond to the header_size passed
// to the Pickle constructor.
template <class T>
T* headerT() {
DCHECK_EQ(header_size_, sizeof(T));
return static_cast<T*>(header_);
}
template <class T>
const T* headerT() const {
DCHECK_EQ(header_size_, sizeof(T));
return static_cast<const T*>(header_);
}
// The payload is the pickle data immediately following the header.
size_t payload_size() const {
return header_ ? header_->payload_size : 0;
}
const char* payload() const {
return reinterpret_cast<const char*>(header_) + header_size_;
}
// Returns the address of the byte immediately following the currently valid
// header + payload.
const char* end_of_payload() const {
// This object may be invalid.
return header_ ? payload() + payload_size() : NULL;
}
protected:
char* mutable_payload() {
return reinterpret_cast<char*>(header_) + header_size_;
}
size_t capacity_after_header() const {
return capacity_after_header_;
}
// Resize the capacity, note that the input value should not include the size
// of the header.
void Resize(size_t new_capacity);
// Aligns 'i' by rounding it up to the next multiple of 'alignment'
static size_t AlignInt(size_t i, int alignment) {
return i + (alignment - (i % alignment)) % alignment;
}
// Find the end of the pickled data that starts at range_start. Returns NULL
// if the entire Pickle is not found in the given data range.
static const char* FindNext(size_t header_size,
const char* range_start,
const char* range_end);
// The allocation granularity of the payload.
static const int kPayloadUnit;
private:
friend class PickleIterator;
Header* header_;
size_t header_size_; // Supports extra data between header and payload.
// Allocation size of payload (or -1 if allocation is const). Note: this
// doesn't count the header.
size_t capacity_after_header_;
// The offset at which we will write the next field. Note: this doesn't count
// the header.
size_t write_offset_;
// Just like WriteBytes, but with a compile-time size, for performance.
template<size_t length> void BASE_EXPORT WriteBytesStatic(const void* data);
// Writes a POD by copying its bytes.
template <typename T> bool WritePOD(const T& data) {
WriteBytesStatic<sizeof(data)>(&data);
return true;
}
inline void WriteBytesCommon(const void* data, size_t length);
FRIEND_TEST_ALL_PREFIXES(PickleTest, Resize);
FRIEND_TEST_ALL_PREFIXES(PickleTest, FindNext);
FRIEND_TEST_ALL_PREFIXES(PickleTest, FindNextWithIncompleteHeader);
FRIEND_TEST_ALL_PREFIXES(PickleTest, FindNextOverflow);
};
#endif // BASE_PICKLE_H__
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