1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16#ifndef ART_RUNTIME_MIRROR_STRING_INL_H_
17#define ART_RUNTIME_MIRROR_STRING_INL_H_
18
19#include "string.h"
20
21#include "android-base/stringprintf.h"
22
23#include "array.h"
24#include "base/bit_utils.h"
25#include "class.h"
26#include "common_throws.h"
27#include "gc/heap-inl.h"
28#include "globals.h"
29#include "intern_table.h"
30#include "runtime.h"
31#include "thread.h"
32#include "utf.h"
33#include "utils.h"
34
35namespace art {
36namespace mirror {
37
38inline uint32_t String::ClassSize(PointerSize pointer_size) {
39  uint32_t vtable_entries = Object::kVTableLength + 56;
40  return Class::ComputeClassSize(true, vtable_entries, 0, 0, 0, 1, 2, pointer_size);
41}
42
43// Sets string count in the allocation code path to ensure it is guarded by a CAS.
44class SetStringCountVisitor {
45 public:
46  explicit SetStringCountVisitor(int32_t count) : count_(count) {
47  }
48
49  void operator()(ObjPtr<Object> obj, size_t usable_size ATTRIBUTE_UNUSED) const
50      REQUIRES_SHARED(Locks::mutator_lock_) {
51    // Avoid AsString as object is not yet in live bitmap or allocation stack.
52    ObjPtr<String> string = ObjPtr<String>::DownCast(obj);
53    string->SetCount(count_);
54    DCHECK(!string->IsCompressed() || kUseStringCompression);
55  }
56
57 private:
58  const int32_t count_;
59};
60
61// Sets string count and value in the allocation code path to ensure it is guarded by a CAS.
62class SetStringCountAndBytesVisitor {
63 public:
64  SetStringCountAndBytesVisitor(int32_t count, Handle<ByteArray> src_array, int32_t offset,
65                                int32_t high_byte)
66      : count_(count), src_array_(src_array), offset_(offset), high_byte_(high_byte) {
67  }
68
69  void operator()(ObjPtr<Object> obj, size_t usable_size ATTRIBUTE_UNUSED) const
70      REQUIRES_SHARED(Locks::mutator_lock_) {
71    // Avoid AsString as object is not yet in live bitmap or allocation stack.
72    ObjPtr<String> string = ObjPtr<String>::DownCast(obj);
73    string->SetCount(count_);
74    DCHECK(!string->IsCompressed() || kUseStringCompression);
75    int32_t length = String::GetLengthFromCount(count_);
76    const uint8_t* const src = reinterpret_cast<uint8_t*>(src_array_->GetData()) + offset_;
77    if (string->IsCompressed()) {
78      uint8_t* valueCompressed = string->GetValueCompressed();
79      for (int i = 0; i < length; i++) {
80        valueCompressed[i] = (src[i] & 0xFF);
81      }
82    } else {
83      uint16_t* value = string->GetValue();
84      for (int i = 0; i < length; i++) {
85        value[i] = high_byte_ + (src[i] & 0xFF);
86      }
87    }
88  }
89
90 private:
91  const int32_t count_;
92  Handle<ByteArray> src_array_;
93  const int32_t offset_;
94  const int32_t high_byte_;
95};
96
97// Sets string count and value in the allocation code path to ensure it is guarded by a CAS.
98class SetStringCountAndValueVisitorFromCharArray {
99 public:
100  SetStringCountAndValueVisitorFromCharArray(int32_t count, Handle<CharArray> src_array,
101                                             int32_t offset) :
102    count_(count), src_array_(src_array), offset_(offset) {
103  }
104
105  void operator()(ObjPtr<Object> obj, size_t usable_size ATTRIBUTE_UNUSED) const
106      REQUIRES_SHARED(Locks::mutator_lock_) {
107    // Avoid AsString as object is not yet in live bitmap or allocation stack.
108    ObjPtr<String> string = ObjPtr<String>::DownCast(obj);
109    string->SetCount(count_);
110    const uint16_t* const src = src_array_->GetData() + offset_;
111    const int32_t length = String::GetLengthFromCount(count_);
112    if (kUseStringCompression && String::IsCompressed(count_)) {
113      for (int i = 0; i < length; ++i) {
114        string->GetValueCompressed()[i] = static_cast<uint8_t>(src[i]);
115      }
116    } else {
117      memcpy(string->GetValue(), src, length * sizeof(uint16_t));
118    }
119  }
120
121 private:
122  const int32_t count_;
123  Handle<CharArray> src_array_;
124  const int32_t offset_;
125};
126
127// Sets string count and value in the allocation code path to ensure it is guarded by a CAS.
128class SetStringCountAndValueVisitorFromString {
129 public:
130  SetStringCountAndValueVisitorFromString(int32_t count,
131                                          Handle<String> src_string,
132                                          int32_t offset) :
133    count_(count), src_string_(src_string), offset_(offset) {
134  }
135
136  void operator()(ObjPtr<Object> obj, size_t usable_size ATTRIBUTE_UNUSED) const
137      REQUIRES_SHARED(Locks::mutator_lock_) {
138    // Avoid AsString as object is not yet in live bitmap or allocation stack.
139    ObjPtr<String> string = ObjPtr<String>::DownCast(obj);
140    string->SetCount(count_);
141    const int32_t length = String::GetLengthFromCount(count_);
142    bool compressible = kUseStringCompression && String::IsCompressed(count_);
143    if (src_string_->IsCompressed()) {
144      const uint8_t* const src = src_string_->GetValueCompressed() + offset_;
145      memcpy(string->GetValueCompressed(), src, length * sizeof(uint8_t));
146    } else {
147      const uint16_t* const src = src_string_->GetValue() + offset_;
148      if (compressible) {
149        for (int i = 0; i < length; ++i) {
150          string->GetValueCompressed()[i] = static_cast<uint8_t>(src[i]);
151        }
152      } else {
153        memcpy(string->GetValue(), src, length * sizeof(uint16_t));
154      }
155    }
156  }
157
158 private:
159  const int32_t count_;
160  Handle<String> src_string_;
161  const int32_t offset_;
162};
163
164inline ObjPtr<String> String::Intern() {
165  return Runtime::Current()->GetInternTable()->InternWeak(this);
166}
167
168inline uint16_t String::CharAt(int32_t index) {
169  int32_t count = GetLength();
170  if (UNLIKELY((index < 0) || (index >= count))) {
171    ThrowStringIndexOutOfBoundsException(index, count);
172    return 0;
173  }
174  if (IsCompressed()) {
175    return GetValueCompressed()[index];
176  } else {
177    return GetValue()[index];
178  }
179}
180
181template <typename MemoryType>
182int32_t String::FastIndexOf(MemoryType* chars, int32_t ch, int32_t start) {
183  const MemoryType* p = chars + start;
184  const MemoryType* end = chars + GetLength();
185  while (p < end) {
186    if (*p++ == ch) {
187      return (p - 1) - chars;
188    }
189  }
190  return -1;
191}
192
193template<VerifyObjectFlags kVerifyFlags>
194inline size_t String::SizeOf() {
195  size_t size = sizeof(String);
196  if (IsCompressed()) {
197    size += (sizeof(uint8_t) * GetLength<kVerifyFlags>());
198  } else {
199    size += (sizeof(uint16_t) * GetLength<kVerifyFlags>());
200  }
201  // String.equals() intrinsics assume zero-padding up to kObjectAlignment,
202  // so make sure the zero-padding is actually copied around if GC compaction
203  // chooses to copy only SizeOf() bytes.
204  // http://b/23528461
205  return RoundUp(size, kObjectAlignment);
206}
207
208template <bool kIsInstrumented, typename PreFenceVisitor>
209inline String* String::Alloc(Thread* self, int32_t utf16_length_with_flag,
210                             gc::AllocatorType allocator_type,
211                             const PreFenceVisitor& pre_fence_visitor) {
212  constexpr size_t header_size = sizeof(String);
213  const bool compressible = kUseStringCompression && String::IsCompressed(utf16_length_with_flag);
214  const size_t block_size = (compressible) ? sizeof(uint8_t) : sizeof(uint16_t);
215  size_t length = String::GetLengthFromCount(utf16_length_with_flag);
216  static_assert(sizeof(length) <= sizeof(size_t),
217                "static_cast<size_t>(utf16_length) must not lose bits.");
218  size_t data_size = block_size * length;
219  size_t size = header_size + data_size;
220  // String.equals() intrinsics assume zero-padding up to kObjectAlignment,
221  // so make sure the allocator clears the padding as well.
222  // http://b/23528461
223  size_t alloc_size = RoundUp(size, kObjectAlignment);
224
225  Class* string_class = GetJavaLangString();
226  // Check for overflow and throw OutOfMemoryError if this was an unreasonable request.
227  // Do this by comparing with the maximum length that will _not_ cause an overflow.
228  const size_t overflow_length = (-header_size) / block_size;   // Unsigned arithmetic.
229  const size_t max_alloc_length = overflow_length - 1u;
230  static_assert(IsAligned<sizeof(uint16_t)>(kObjectAlignment),
231                "kObjectAlignment must be at least as big as Java char alignment");
232  const size_t max_length = RoundDown(max_alloc_length, kObjectAlignment / block_size);
233  if (UNLIKELY(length > max_length)) {
234    self->ThrowOutOfMemoryError(
235        android::base::StringPrintf("%s of length %d would overflow",
236                                    Class::PrettyDescriptor(string_class).c_str(),
237                                    static_cast<int>(length)).c_str());
238    return nullptr;
239  }
240
241  gc::Heap* heap = Runtime::Current()->GetHeap();
242  return down_cast<String*>(
243      heap->AllocObjectWithAllocator<kIsInstrumented, true>(self, string_class, alloc_size,
244                                                            allocator_type, pre_fence_visitor));
245}
246
247template <bool kIsInstrumented>
248inline String* String::AllocEmptyString(Thread* self, gc::AllocatorType allocator_type) {
249  const int32_t length_with_flag = String::GetFlaggedCount(0, /* compressible */ true);
250  SetStringCountVisitor visitor(length_with_flag);
251  return Alloc<kIsInstrumented>(self, length_with_flag, allocator_type, visitor);
252}
253
254template <bool kIsInstrumented>
255inline String* String::AllocFromByteArray(Thread* self, int32_t byte_length,
256                                          Handle<ByteArray> array, int32_t offset,
257                                          int32_t high_byte, gc::AllocatorType allocator_type) {
258  const uint8_t* const src = reinterpret_cast<uint8_t*>(array->GetData()) + offset;
259  const bool compressible =
260      kUseStringCompression && String::AllASCII<uint8_t>(src, byte_length) && (high_byte == 0);
261  const int32_t length_with_flag = String::GetFlaggedCount(byte_length, compressible);
262  SetStringCountAndBytesVisitor visitor(length_with_flag, array, offset, high_byte << 8);
263  String* string = Alloc<kIsInstrumented>(self, length_with_flag, allocator_type, visitor);
264  return string;
265}
266
267template <bool kIsInstrumented>
268inline String* String::AllocFromCharArray(Thread* self, int32_t count,
269                                          Handle<CharArray> array, int32_t offset,
270                                          gc::AllocatorType allocator_type) {
271  // It is a caller error to have a count less than the actual array's size.
272  DCHECK_GE(array->GetLength(), count);
273  const bool compressible = kUseStringCompression &&
274                            String::AllASCII<uint16_t>(array->GetData() + offset, count);
275  const int32_t length_with_flag = String::GetFlaggedCount(count, compressible);
276  SetStringCountAndValueVisitorFromCharArray visitor(length_with_flag, array, offset);
277  String* new_string = Alloc<kIsInstrumented>(self, length_with_flag, allocator_type, visitor);
278  return new_string;
279}
280
281template <bool kIsInstrumented>
282inline String* String::AllocFromString(Thread* self, int32_t string_length, Handle<String> string,
283                                       int32_t offset, gc::AllocatorType allocator_type) {
284  const bool compressible = kUseStringCompression &&
285      ((string->IsCompressed()) ? true : String::AllASCII<uint16_t>(string->GetValue() + offset,
286                                                                    string_length));
287  const int32_t length_with_flag = String::GetFlaggedCount(string_length, compressible);
288  SetStringCountAndValueVisitorFromString visitor(length_with_flag, string, offset);
289  String* new_string = Alloc<kIsInstrumented>(self, length_with_flag, allocator_type, visitor);
290  return new_string;
291}
292
293inline int32_t String::GetHashCode() {
294  int32_t result = GetField32(OFFSET_OF_OBJECT_MEMBER(String, hash_code_));
295  if (UNLIKELY(result == 0)) {
296    result = ComputeHashCode();
297  }
298  if (kIsDebugBuild) {
299    if (IsCompressed()) {
300      DCHECK(result != 0 || ComputeUtf16Hash(GetValueCompressed(), GetLength()) == 0)
301          << ToModifiedUtf8() << " " << result;
302    } else {
303      DCHECK(result != 0 || ComputeUtf16Hash(GetValue(), GetLength()) == 0)
304          << ToModifiedUtf8() << " " << result;
305    }
306  }
307  return result;
308}
309
310template<typename MemoryType>
311inline bool String::AllASCII(const MemoryType* chars, const int length) {
312  static_assert(std::is_unsigned<MemoryType>::value, "Expecting unsigned MemoryType");
313  for (int i = 0; i < length; ++i) {
314    if (!IsASCII(chars[i])) {
315      return false;
316    }
317  }
318  return true;
319}
320
321inline bool String::DexFileStringAllASCII(const char* chars, const int length) {
322  // For strings from the dex file we just need to check that
323  // the terminating character is at the right position.
324  DCHECK_EQ(AllASCII(reinterpret_cast<const uint8_t*>(chars), length), chars[length] == 0);
325  return chars[length] == 0;
326}
327
328}  // namespace mirror
329}  // namespace art
330
331#endif  // ART_RUNTIME_MIRROR_STRING_INL_H_
332