1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "base/pickle.h"
6
7#include <stdlib.h>
8
9#include <algorithm>  // for max()
10
11//------------------------------------------------------------------------------
12
13// static
14const int Pickle::kPayloadUnit = 64;
15
16static const size_t kCapacityReadOnly = static_cast<size_t>(-1);
17
18PickleIterator::PickleIterator(const Pickle& pickle)
19    : read_ptr_(pickle.payload()),
20      read_end_ptr_(pickle.end_of_payload()) {
21}
22
23template <typename Type>
24inline bool PickleIterator::ReadBuiltinType(Type* result) {
25  const char* read_from = GetReadPointerAndAdvance<Type>();
26  if (!read_from)
27    return false;
28  if (sizeof(Type) > sizeof(uint32))
29    memcpy(result, read_from, sizeof(*result));
30  else
31    *result = *reinterpret_cast<const Type*>(read_from);
32  return true;
33}
34
35template<typename Type>
36inline const char* PickleIterator::GetReadPointerAndAdvance() {
37  const char* current_read_ptr = read_ptr_;
38  if (read_ptr_ + sizeof(Type) > read_end_ptr_)
39    return NULL;
40  if (sizeof(Type) < sizeof(uint32))
41    read_ptr_ += AlignInt(sizeof(Type), sizeof(uint32));
42  else
43    read_ptr_ += sizeof(Type);
44  return current_read_ptr;
45}
46
47const char* PickleIterator::GetReadPointerAndAdvance(int num_bytes) {
48  if (num_bytes < 0 || read_end_ptr_ - read_ptr_ < num_bytes)
49    return NULL;
50  const char* current_read_ptr = read_ptr_;
51  read_ptr_ += AlignInt(num_bytes, sizeof(uint32));
52  return current_read_ptr;
53}
54
55inline const char* PickleIterator::GetReadPointerAndAdvance(int num_elements,
56                                                          size_t size_element) {
57  // Check for int32 overflow.
58  int64 num_bytes = static_cast<int64>(num_elements) * size_element;
59  int num_bytes32 = static_cast<int>(num_bytes);
60  if (num_bytes != static_cast<int64>(num_bytes32))
61    return NULL;
62  return GetReadPointerAndAdvance(num_bytes32);
63}
64
65bool PickleIterator::ReadBool(bool* result) {
66  return ReadBuiltinType(result);
67}
68
69bool PickleIterator::ReadInt(int* result) {
70  return ReadBuiltinType(result);
71}
72
73bool PickleIterator::ReadLong(long* result) {
74  return ReadBuiltinType(result);
75}
76
77bool PickleIterator::ReadUInt16(uint16* result) {
78  return ReadBuiltinType(result);
79}
80
81bool PickleIterator::ReadUInt32(uint32* result) {
82  return ReadBuiltinType(result);
83}
84
85bool PickleIterator::ReadInt64(int64* result) {
86  return ReadBuiltinType(result);
87}
88
89bool PickleIterator::ReadUInt64(uint64* result) {
90  return ReadBuiltinType(result);
91}
92
93bool PickleIterator::ReadFloat(float* result) {
94  return ReadBuiltinType(result);
95}
96
97bool PickleIterator::ReadString(std::string* result) {
98  int len;
99  if (!ReadInt(&len))
100    return false;
101  const char* read_from = GetReadPointerAndAdvance(len);
102  if (!read_from)
103    return false;
104
105  result->assign(read_from, len);
106  return true;
107}
108
109bool PickleIterator::ReadWString(std::wstring* result) {
110  int len;
111  if (!ReadInt(&len))
112    return false;
113  const char* read_from = GetReadPointerAndAdvance(len, sizeof(wchar_t));
114  if (!read_from)
115    return false;
116
117  result->assign(reinterpret_cast<const wchar_t*>(read_from), len);
118  return true;
119}
120
121bool PickleIterator::ReadString16(string16* result) {
122  int len;
123  if (!ReadInt(&len))
124    return false;
125  const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16));
126  if (!read_from)
127    return false;
128
129  result->assign(reinterpret_cast<const char16*>(read_from), len);
130  return true;
131}
132
133bool PickleIterator::ReadData(const char** data, int* length) {
134  *length = 0;
135  *data = 0;
136
137  if (!ReadInt(length))
138    return false;
139
140  return ReadBytes(data, *length);
141}
142
143bool PickleIterator::ReadBytes(const char** data, int length) {
144  const char* read_from = GetReadPointerAndAdvance(length);
145  if (!read_from)
146    return false;
147  *data = read_from;
148  return true;
149}
150
151// Payload is uint32 aligned.
152
153Pickle::Pickle()
154    : header_(NULL),
155      header_size_(sizeof(Header)),
156      capacity_(0),
157      variable_buffer_offset_(0) {
158  Resize(kPayloadUnit);
159  header_->payload_size = 0;
160}
161
162Pickle::Pickle(int header_size)
163    : header_(NULL),
164      header_size_(AlignInt(header_size, sizeof(uint32))),
165      capacity_(0),
166      variable_buffer_offset_(0) {
167  DCHECK_GE(static_cast<size_t>(header_size), sizeof(Header));
168  DCHECK_LE(header_size, kPayloadUnit);
169  Resize(kPayloadUnit);
170  header_->payload_size = 0;
171}
172
173Pickle::Pickle(const char* data, int data_len)
174    : header_(reinterpret_cast<Header*>(const_cast<char*>(data))),
175      header_size_(0),
176      capacity_(kCapacityReadOnly),
177      variable_buffer_offset_(0) {
178  if (data_len >= static_cast<int>(sizeof(Header)))
179    header_size_ = data_len - header_->payload_size;
180
181  if (header_size_ > static_cast<unsigned int>(data_len))
182    header_size_ = 0;
183
184  if (header_size_ != AlignInt(header_size_, sizeof(uint32)))
185    header_size_ = 0;
186
187  // If there is anything wrong with the data, we're not going to use it.
188  if (!header_size_)
189    header_ = NULL;
190}
191
192Pickle::Pickle(const Pickle& other)
193    : header_(NULL),
194      header_size_(other.header_size_),
195      capacity_(0),
196      variable_buffer_offset_(other.variable_buffer_offset_) {
197  size_t payload_size = header_size_ + other.header_->payload_size;
198  bool resized = Resize(payload_size);
199  CHECK(resized);  // Realloc failed.
200  memcpy(header_, other.header_, payload_size);
201}
202
203Pickle::~Pickle() {
204  if (capacity_ != kCapacityReadOnly)
205    free(header_);
206}
207
208Pickle& Pickle::operator=(const Pickle& other) {
209  if (this == &other) {
210    NOTREACHED();
211    return *this;
212  }
213  if (capacity_ == kCapacityReadOnly) {
214    header_ = NULL;
215    capacity_ = 0;
216  }
217  if (header_size_ != other.header_size_) {
218    free(header_);
219    header_ = NULL;
220    header_size_ = other.header_size_;
221  }
222  bool resized = Resize(other.header_size_ + other.header_->payload_size);
223  CHECK(resized);  // Realloc failed.
224  memcpy(header_, other.header_,
225         other.header_size_ + other.header_->payload_size);
226  variable_buffer_offset_ = other.variable_buffer_offset_;
227  return *this;
228}
229
230bool Pickle::WriteString(const std::string& value) {
231  if (!WriteInt(static_cast<int>(value.size())))
232    return false;
233
234  return WriteBytes(value.data(), static_cast<int>(value.size()));
235}
236
237bool Pickle::WriteWString(const std::wstring& value) {
238  if (!WriteInt(static_cast<int>(value.size())))
239    return false;
240
241  return WriteBytes(value.data(),
242                    static_cast<int>(value.size() * sizeof(wchar_t)));
243}
244
245bool Pickle::WriteString16(const string16& value) {
246  if (!WriteInt(static_cast<int>(value.size())))
247    return false;
248
249  return WriteBytes(value.data(),
250                    static_cast<int>(value.size()) * sizeof(char16));
251}
252
253bool Pickle::WriteData(const char* data, int length) {
254  return length >= 0 && WriteInt(length) && WriteBytes(data, length);
255}
256
257bool Pickle::WriteBytes(const void* data, int data_len) {
258  DCHECK_NE(kCapacityReadOnly, capacity_) << "oops: pickle is readonly";
259
260  char* dest = BeginWrite(data_len);
261  if (!dest)
262    return false;
263
264  memcpy(dest, data, data_len);
265
266  EndWrite(dest, data_len);
267  return true;
268}
269
270char* Pickle::BeginWriteData(int length) {
271  DCHECK_EQ(variable_buffer_offset_, 0U) <<
272    "There can only be one variable buffer in a Pickle";
273
274  if (length < 0 || !WriteInt(length))
275    return NULL;
276
277  char *data_ptr = BeginWrite(length);
278  if (!data_ptr)
279    return NULL;
280
281  variable_buffer_offset_ =
282      data_ptr - reinterpret_cast<char*>(header_) - sizeof(int);
283
284  // EndWrite doesn't necessarily have to be called after the write operation,
285  // so we call it here to pad out what the caller will eventually write.
286  EndWrite(data_ptr, length);
287  return data_ptr;
288}
289
290void Pickle::TrimWriteData(int new_length) {
291  DCHECK_NE(variable_buffer_offset_, 0U);
292
293  // Fetch the the variable buffer size
294  int* cur_length = reinterpret_cast<int*>(
295      reinterpret_cast<char*>(header_) + variable_buffer_offset_);
296
297  if (new_length < 0 || new_length > *cur_length) {
298    NOTREACHED() << "Invalid length in TrimWriteData.";
299    return;
300  }
301
302  // Update the payload size and variable buffer size
303  header_->payload_size -= (*cur_length - new_length);
304  *cur_length = new_length;
305}
306
307char* Pickle::BeginWrite(size_t length) {
308  // write at a uint32-aligned offset from the beginning of the header
309  size_t offset = AlignInt(header_->payload_size, sizeof(uint32));
310
311  size_t new_size = offset + length;
312  size_t needed_size = header_size_ + new_size;
313  if (needed_size > capacity_ && !Resize(std::max(capacity_ * 2, needed_size)))
314    return NULL;
315
316#ifdef ARCH_CPU_64_BITS
317  DCHECK_LE(length, kuint32max);
318#endif
319
320  header_->payload_size = static_cast<uint32>(new_size);
321  return mutable_payload() + offset;
322}
323
324void Pickle::EndWrite(char* dest, int length) {
325  // Zero-pad to keep tools like valgrind from complaining about uninitialized
326  // memory.
327  if (length % sizeof(uint32))
328    memset(dest + length, 0, sizeof(uint32) - (length % sizeof(uint32)));
329}
330
331bool Pickle::Resize(size_t new_capacity) {
332  new_capacity = AlignInt(new_capacity, kPayloadUnit);
333
334  CHECK_NE(capacity_, kCapacityReadOnly);
335  void* p = realloc(header_, new_capacity);
336  if (!p)
337    return false;
338
339  header_ = reinterpret_cast<Header*>(p);
340  capacity_ = new_capacity;
341  return true;
342}
343
344// static
345const char* Pickle::FindNext(size_t header_size,
346                             const char* start,
347                             const char* end) {
348  DCHECK_EQ(header_size, AlignInt(header_size, sizeof(uint32)));
349  DCHECK_LE(header_size, static_cast<size_t>(kPayloadUnit));
350
351  if (static_cast<size_t>(end - start) < sizeof(Header))
352    return NULL;
353
354  const Header* hdr = reinterpret_cast<const Header*>(start);
355  const char* payload_base = start + header_size;
356  const char* payload_end = payload_base + hdr->payload_size;
357  if (payload_end < payload_base)
358    return NULL;
359
360  return (payload_end > end) ? NULL : payload_end;
361}
362