| /* |
| * Copyright (C) 2019 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "string_builder_append.h" |
| |
| #include "base/casts.h" |
| #include "base/logging.h" |
| #include "common_throws.h" |
| #include "gc/heap.h" |
| #include "mirror/string-alloc-inl.h" |
| #include "obj_ptr-inl.h" |
| #include "runtime.h" |
| |
| namespace art { |
| |
| class StringBuilderAppend::Builder { |
| public: |
| Builder(uint32_t format, const uint32_t* args, Thread* self) |
| : format_(format), |
| args_(args), |
| hs_(self) {} |
| |
| int32_t CalculateLengthWithFlag() REQUIRES_SHARED(Locks::mutator_lock_); |
| |
| void operator()(ObjPtr<mirror::Object> obj, size_t usable_size) const |
| REQUIRES_SHARED(Locks::mutator_lock_); |
| |
| private: |
| static size_t Uint64Length(uint64_t value); |
| |
| static size_t Int64Length(int64_t value) { |
| uint64_t v = static_cast<uint64_t>(value); |
| return (value >= 0) ? Uint64Length(v) : 1u + Uint64Length(-v); |
| } |
| |
| static size_t RemainingSpace(ObjPtr<mirror::String> new_string, const uint8_t* data) |
| REQUIRES_SHARED(Locks::mutator_lock_) { |
| DCHECK(new_string->IsCompressed()); |
| DCHECK_GE(new_string->GetLength(), data - new_string->GetValueCompressed()); |
| return new_string->GetLength() - (data - new_string->GetValueCompressed()); |
| } |
| |
| static size_t RemainingSpace(ObjPtr<mirror::String> new_string, const uint16_t* data) |
| REQUIRES_SHARED(Locks::mutator_lock_) { |
| DCHECK(!new_string->IsCompressed()); |
| DCHECK_GE(new_string->GetLength(), data - new_string->GetValue()); |
| return new_string->GetLength() - (data - new_string->GetValue()); |
| } |
| |
| template <typename CharType, size_t size> |
| static CharType* AppendLiteral(ObjPtr<mirror::String> new_string, |
| CharType* data, |
| const char (&literal)[size]) REQUIRES_SHARED(Locks::mutator_lock_); |
| |
| template <typename CharType> |
| static CharType* AppendString(ObjPtr<mirror::String> new_string, |
| CharType* data, |
| ObjPtr<mirror::String> str) REQUIRES_SHARED(Locks::mutator_lock_); |
| |
| template <typename CharType> |
| static CharType* AppendInt64(ObjPtr<mirror::String> new_string, |
| CharType* data, |
| int64_t value) REQUIRES_SHARED(Locks::mutator_lock_); |
| |
| template <typename CharType> |
| void StoreData(ObjPtr<mirror::String> new_string, CharType* data) const |
| REQUIRES_SHARED(Locks::mutator_lock_); |
| |
| static constexpr char kNull[] = "null"; |
| static constexpr size_t kNullLength = sizeof(kNull) - 1u; |
| static constexpr char kTrue[] = "true"; |
| static constexpr size_t kTrueLength = sizeof(kTrue) - 1u; |
| static constexpr char kFalse[] = "false"; |
| static constexpr size_t kFalseLength = sizeof(kFalse) - 1u; |
| |
| // The format and arguments to append. |
| const uint32_t format_; |
| const uint32_t* const args_; |
| |
| // References are moved to the handle scope during CalculateLengthWithFlag(). |
| StackHandleScope<kMaxArgs> hs_; |
| |
| // The length and flag to store when the AppendBuilder is used as a pre-fence visitor. |
| int32_t length_with_flag_ = 0u; |
| }; |
| |
| inline size_t StringBuilderAppend::Builder::Uint64Length(uint64_t value) { |
| if (value == 0u) { |
| return 1u; |
| } |
| // Calculate floor(log2(value)). |
| size_t log2_value = BitSizeOf<uint64_t>() - 1u - CLZ(value); |
| // Calculate an estimate of floor(log10(value)). |
| // log10(2) = 0.301029996 > 0.296875 = 19/64 |
| // floor(log10(v)) == floor(log2(v) * log10(2)) |
| // >= floor(log2(v) * 19/64) |
| // >= floor(floor(log2(v)) * 19/64) |
| // This estimate is no more that one off from the actual value because log2(value) < 64 and thus |
| // log2(v) * log10(2) - log2(v) * 19/64 < 64*(log10(2) - 19/64) |
| // for the first approximation and |
| // log2(v) * 19/64 - floor(log2(v)) * 19/64 < 19/64 |
| // for the second one. Together, |
| // 64*(log10(2) - 19/64) + 19/64 = 0.56278 < 1 . |
| size_t log10_value_estimate = log2_value * 19u / 64u; |
| static constexpr uint64_t bounds[] = { |
| UINT64_C(9), |
| UINT64_C(99), |
| UINT64_C(999), |
| UINT64_C(9999), |
| UINT64_C(99999), |
| UINT64_C(999999), |
| UINT64_C(9999999), |
| UINT64_C(99999999), |
| UINT64_C(999999999), |
| UINT64_C(9999999999), |
| UINT64_C(99999999999), |
| UINT64_C(999999999999), |
| UINT64_C(9999999999999), |
| UINT64_C(99999999999999), |
| UINT64_C(999999999999999), |
| UINT64_C(9999999999999999), |
| UINT64_C(99999999999999999), |
| UINT64_C(999999999999999999), |
| UINT64_C(9999999999999999999), |
| }; |
| // Add 1 for the lowest digit, add another 1 if the estimate was too low. |
| DCHECK_LT(log10_value_estimate, std::size(bounds)); |
| size_t adjustment = (value > bounds[log10_value_estimate]) ? 2u : 1u; |
| return log10_value_estimate + adjustment; |
| } |
| |
| template <typename CharType, size_t size> |
| inline CharType* StringBuilderAppend::Builder::AppendLiteral(ObjPtr<mirror::String> new_string, |
| CharType* data, |
| const char (&literal)[size]) { |
| static_assert(size >= 2, "We need something to append."); |
| |
| // Literals are zero-terminated. |
| constexpr size_t length = size - 1u; |
| DCHECK_EQ(literal[length], '\0'); |
| |
| DCHECK_LE(length, RemainingSpace(new_string, data)); |
| for (size_t i = 0; i != length; ++i) { |
| data[i] = literal[i]; |
| } |
| return data + length; |
| } |
| |
| template <typename CharType> |
| inline CharType* StringBuilderAppend::Builder::AppendString(ObjPtr<mirror::String> new_string, |
| CharType* data, |
| ObjPtr<mirror::String> str) { |
| size_t length = dchecked_integral_cast<size_t>(str->GetLength()); |
| DCHECK_LE(length, RemainingSpace(new_string, data)); |
| if (sizeof(CharType) == sizeof(uint8_t) || str->IsCompressed()) { |
| DCHECK(str->IsCompressed()); |
| const uint8_t* value = str->GetValueCompressed(); |
| for (size_t i = 0; i != length; ++i) { |
| data[i] = value[i]; |
| } |
| } else { |
| const uint16_t* value = str->GetValue(); |
| for (size_t i = 0; i != length; ++i) { |
| data[i] = dchecked_integral_cast<CharType>(value[i]); |
| } |
| } |
| return data + length; |
| } |
| |
| template <typename CharType> |
| inline CharType* StringBuilderAppend::Builder::AppendInt64(ObjPtr<mirror::String> new_string, |
| CharType* data, |
| int64_t value) { |
| DCHECK_GE(RemainingSpace(new_string, data), Int64Length(value)); |
| uint64_t v = static_cast<uint64_t>(value); |
| if (value < 0) { |
| *data = '-'; |
| ++data; |
| v = -v; |
| } |
| size_t length = Uint64Length(v); |
| // Write the digits from the end, do not write the most significant digit |
| // in the loop to avoid an unnecessary division. |
| for (size_t i = 1; i != length; ++i) { |
| uint64_t digit = v % UINT64_C(10); |
| v /= UINT64_C(10); |
| data[length - i] = '0' + static_cast<char>(digit); |
| } |
| DCHECK_LE(v, 10u); |
| *data = '0' + static_cast<char>(v); |
| return data + length; |
| } |
| |
| inline int32_t StringBuilderAppend::Builder::CalculateLengthWithFlag() { |
| static_assert(static_cast<size_t>(Argument::kEnd) == 0u, "kEnd must be 0."); |
| bool compressible = mirror::kUseStringCompression; |
| uint64_t length = 0u; |
| const uint32_t* current_arg = args_; |
| for (uint32_t f = format_; f != 0u; f >>= kBitsPerArg) { |
| DCHECK_LE(f & kArgMask, static_cast<uint32_t>(Argument::kLast)); |
| switch (static_cast<Argument>(f & kArgMask)) { |
| case Argument::kString: { |
| Handle<mirror::String> str = |
| hs_.NewHandle(reinterpret_cast32<mirror::String*>(*current_arg)); |
| if (str != nullptr) { |
| length += str->GetLength(); |
| compressible = compressible && str->IsCompressed(); |
| } else { |
| length += kNullLength; |
| } |
| break; |
| } |
| case Argument::kBoolean: { |
| length += (*current_arg != 0u) ? kTrueLength : kFalseLength; |
| break; |
| } |
| case Argument::kChar: { |
| length += 1u; |
| compressible = compressible && |
| mirror::String::IsASCII(reinterpret_cast<const uint16_t*>(current_arg)[0]); |
| break; |
| } |
| case Argument::kInt: { |
| length += Int64Length(static_cast<int32_t>(*current_arg)); |
| break; |
| } |
| case Argument::kLong: { |
| current_arg = AlignUp(current_arg, sizeof(int64_t)); |
| length += Int64Length(*reinterpret_cast<const int64_t*>(current_arg)); |
| ++current_arg; // Skip the low word, let the common code skip the high word. |
| break; |
| } |
| |
| case Argument::kStringBuilder: |
| case Argument::kCharArray: |
| case Argument::kObject: |
| case Argument::kFloat: |
| case Argument::kDouble: |
| LOG(FATAL) << "Unimplemented arg format: 0x" << std::hex |
| << (f & kArgMask) << " full format: 0x" << std::hex << format_; |
| UNREACHABLE(); |
| default: |
| LOG(FATAL) << "Unexpected arg format: 0x" << std::hex |
| << (f & kArgMask) << " full format: 0x" << std::hex << format_; |
| UNREACHABLE(); |
| } |
| ++current_arg; |
| DCHECK_LE(hs_.NumberOfReferences(), kMaxArgs); |
| } |
| |
| if (length > std::numeric_limits<int32_t>::max()) { |
| // We cannot allocate memory for the entire result. |
| hs_.Self()->ThrowNewException("Ljava/lang/OutOfMemoryError;", |
| "Out of memory for StringBuilder append."); |
| return -1; |
| } |
| |
| length_with_flag_ = mirror::String::GetFlaggedCount(length, compressible); |
| return length_with_flag_; |
| } |
| |
| template <typename CharType> |
| inline void StringBuilderAppend::Builder::StoreData(ObjPtr<mirror::String> new_string, |
| CharType* data) const { |
| size_t handle_index = 0u; |
| const uint32_t* current_arg = args_; |
| for (uint32_t f = format_; f != 0u; f >>= kBitsPerArg) { |
| DCHECK_LE(f & kArgMask, static_cast<uint32_t>(Argument::kLast)); |
| switch (static_cast<Argument>(f & kArgMask)) { |
| case Argument::kString: { |
| ObjPtr<mirror::String> str = |
| ObjPtr<mirror::String>::DownCast(hs_.GetReference(handle_index)); |
| ++handle_index; |
| if (str != nullptr) { |
| data = AppendString(new_string, data, str); |
| } else { |
| data = AppendLiteral(new_string, data, kNull); |
| } |
| break; |
| } |
| case Argument::kBoolean: { |
| if (*current_arg != 0u) { |
| data = AppendLiteral(new_string, data, kTrue); |
| } else { |
| data = AppendLiteral(new_string, data, kFalse); |
| } |
| break; |
| } |
| case Argument::kChar: { |
| DCHECK_GE(RemainingSpace(new_string, data), 1u); |
| *data = *reinterpret_cast<const CharType*>(current_arg); |
| ++data; |
| break; |
| } |
| case Argument::kInt: { |
| data = AppendInt64(new_string, data, static_cast<int32_t>(*current_arg)); |
| break; |
| } |
| case Argument::kLong: { |
| current_arg = AlignUp(current_arg, sizeof(int64_t)); |
| data = AppendInt64(new_string, data, *reinterpret_cast<const int64_t*>(current_arg)); |
| ++current_arg; // Skip the low word, let the common code skip the high word. |
| break; |
| } |
| |
| case Argument::kStringBuilder: |
| case Argument::kCharArray: |
| case Argument::kFloat: |
| case Argument::kDouble: |
| LOG(FATAL) << "Unimplemented arg format: 0x" << std::hex |
| << (f & kArgMask) << " full format: 0x" << std::hex << format_; |
| UNREACHABLE(); |
| default: |
| LOG(FATAL) << "Unexpected arg format: 0x" << std::hex |
| << (f & kArgMask) << " full format: 0x" << std::hex << format_; |
| UNREACHABLE(); |
| } |
| ++current_arg; |
| DCHECK_LE(handle_index, hs_.NumberOfReferences()); |
| } |
| DCHECK_EQ(RemainingSpace(new_string, data), 0u) << std::hex << format_; |
| } |
| |
| inline void StringBuilderAppend::Builder::operator()(ObjPtr<mirror::Object> obj, |
| size_t usable_size ATTRIBUTE_UNUSED) const { |
| ObjPtr<mirror::String> new_string = ObjPtr<mirror::String>::DownCast(obj); |
| new_string->SetCount(length_with_flag_); |
| if (mirror::String::IsCompressed(length_with_flag_)) { |
| StoreData(new_string, new_string->GetValueCompressed()); |
| } else { |
| StoreData(new_string, new_string->GetValue()); |
| } |
| } |
| |
| ObjPtr<mirror::String> StringBuilderAppend::AppendF(uint32_t format, |
| const uint32_t* args, |
| Thread* self) { |
| Builder builder(format, args, self); |
| self->AssertNoPendingException(); |
| int32_t length_with_flag = builder.CalculateLengthWithFlag(); |
| if (self->IsExceptionPending()) { |
| return nullptr; |
| } |
| gc::AllocatorType allocator_type = Runtime::Current()->GetHeap()->GetCurrentAllocator(); |
| ObjPtr<mirror::String> result = mirror::String::Alloc( |
| self, length_with_flag, allocator_type, builder); |
| |
| return result; |
| } |
| |
| } // namespace art |
