king
/
v811_spc009
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
Branches Tags
${ item.name }
Create tag ${ searchTerm }
Create branch ${ searchTerm }
from 'd5f7aa4152'
${ noResults }
v811_spc009/art/runtime/string_builder_append.cc

365 lines
13 KiB
Raw Blame History

/*
* 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
Reference in new issue View Git Blame Copy Permalink