blob: d8354c1f9cef5d46543873e229852bffb178472e [file] [log] [blame]
// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Author: kenton@google.com (Kenton Varda)
// Based on original Protocol Buffers design by
// Sanjay Ghemawat, Jeff Dean, and others.
//
// This implementation is heavily optimized to make reads and writes
// of small values (especially varints) as fast as possible. In
// particular, we optimize for the common case that a read or a write
// will not cross the end of the buffer, since we can avoid a lot
// of branching in this case.
#include <google/protobuf/io/coded_stream_inl.h>
#include <algorithm>
#include <utility>
#include <limits.h>
#include <google/protobuf/io/zero_copy_stream.h>
#include <google/protobuf/arena.h>
#include <google/protobuf/stubs/logging.h>
#include <google/protobuf/stubs/common.h>
#include <google/protobuf/stubs/stl_util.h>
namespace google {
namespace protobuf {
namespace io {
namespace {
static const int kMaxVarintBytes = 10;
static const int kMaxVarint32Bytes = 5;
inline bool NextNonEmpty(ZeroCopyInputStream* input,
const void** data, int* size) {
bool success;
do {
success = input->Next(data, size);
} while (success && *size == 0);
return success;
}
} // namespace
// CodedInputStream ==================================================
CodedInputStream::~CodedInputStream() {
if (input_ != NULL) {
BackUpInputToCurrentPosition();
}
if (total_bytes_warning_threshold_ == -2) {
GOOGLE_LOG(WARNING) << "The total number of bytes read was " << total_bytes_read_;
}
}
// Static.
int CodedInputStream::default_recursion_limit_ = 100;
void CodedOutputStream::EnableAliasing(bool enabled) {
aliasing_enabled_ = enabled && output_->AllowsAliasing();
}
void CodedInputStream::BackUpInputToCurrentPosition() {
int backup_bytes = BufferSize() + buffer_size_after_limit_ + overflow_bytes_;
if (backup_bytes > 0) {
input_->BackUp(backup_bytes);
// total_bytes_read_ doesn't include overflow_bytes_.
total_bytes_read_ -= BufferSize() + buffer_size_after_limit_;
buffer_end_ = buffer_;
buffer_size_after_limit_ = 0;
overflow_bytes_ = 0;
}
}
inline void CodedInputStream::RecomputeBufferLimits() {
buffer_end_ += buffer_size_after_limit_;
int closest_limit = std::min(current_limit_, total_bytes_limit_);
if (closest_limit < total_bytes_read_) {
// The limit position is in the current buffer. We must adjust
// the buffer size accordingly.
buffer_size_after_limit_ = total_bytes_read_ - closest_limit;
buffer_end_ -= buffer_size_after_limit_;
} else {
buffer_size_after_limit_ = 0;
}
}
CodedInputStream::Limit CodedInputStream::PushLimit(int byte_limit) {
// Current position relative to the beginning of the stream.
int current_position = CurrentPosition();
Limit old_limit = current_limit_;
// security: byte_limit is possibly evil, so check for negative values
// and overflow.
if (byte_limit >= 0 &&
byte_limit <= INT_MAX - current_position) {
current_limit_ = current_position + byte_limit;
} else {
// Negative or overflow.
current_limit_ = INT_MAX;
}
// We need to enforce all limits, not just the new one, so if the previous
// limit was before the new requested limit, we continue to enforce the
// previous limit.
current_limit_ = std::min(current_limit_, old_limit);
RecomputeBufferLimits();
return old_limit;
}
void CodedInputStream::PopLimit(Limit limit) {
// The limit passed in is actually the *old* limit, which we returned from
// PushLimit().
current_limit_ = limit;
RecomputeBufferLimits();
// We may no longer be at a legitimate message end. ReadTag() needs to be
// called again to find out.
legitimate_message_end_ = false;
}
std::pair<CodedInputStream::Limit, int>
CodedInputStream::IncrementRecursionDepthAndPushLimit(int byte_limit) {
return std::make_pair(PushLimit(byte_limit), --recursion_budget_);
}
CodedInputStream::Limit CodedInputStream::ReadLengthAndPushLimit() {
uint32 length;
return PushLimit(ReadVarint32(&length) ? length : 0);
}
bool CodedInputStream::DecrementRecursionDepthAndPopLimit(Limit limit) {
bool result = ConsumedEntireMessage();
PopLimit(limit);
GOOGLE_DCHECK_LT(recursion_budget_, recursion_limit_);
++recursion_budget_;
return result;
}
bool CodedInputStream::CheckEntireMessageConsumedAndPopLimit(Limit limit) {
bool result = ConsumedEntireMessage();
PopLimit(limit);
return result;
}
int CodedInputStream::BytesUntilLimit() const {
if (current_limit_ == INT_MAX) return -1;
int current_position = CurrentPosition();
return current_limit_ - current_position;
}
void CodedInputStream::SetTotalBytesLimit(
int total_bytes_limit, int warning_threshold) {
// Make sure the limit isn't already past, since this could confuse other
// code.
int current_position = CurrentPosition();
total_bytes_limit_ = std::max(current_position, total_bytes_limit);
if (warning_threshold >= 0) {
total_bytes_warning_threshold_ = warning_threshold;
} else {
// warning_threshold is negative
total_bytes_warning_threshold_ = -1;
}
RecomputeBufferLimits();
}
int CodedInputStream::BytesUntilTotalBytesLimit() const {
if (total_bytes_limit_ == INT_MAX) return -1;
return total_bytes_limit_ - CurrentPosition();
}
void CodedInputStream::PrintTotalBytesLimitError() {
GOOGLE_LOG(ERROR) << "A protocol message was rejected because it was too "
"big (more than " << total_bytes_limit_
<< " bytes). To increase the limit (or to disable these "
"warnings), see CodedInputStream::SetTotalBytesLimit() "
"in google/protobuf/io/coded_stream.h.";
}
bool CodedInputStream::Skip(int count) {
if (count < 0) return false; // security: count is often user-supplied
const int original_buffer_size = BufferSize();
if (count <= original_buffer_size) {
// Just skipping within the current buffer. Easy.
Advance(count);
return true;
}
if (buffer_size_after_limit_ > 0) {
// We hit a limit inside this buffer. Advance to the limit and fail.
Advance(original_buffer_size);
return false;
}
count -= original_buffer_size;
buffer_ = NULL;
buffer_end_ = buffer_;
// Make sure this skip doesn't try to skip past the current limit.
int closest_limit = std::min(current_limit_, total_bytes_limit_);
int bytes_until_limit = closest_limit - total_bytes_read_;
if (bytes_until_limit < count) {
// We hit the limit. Skip up to it then fail.
if (bytes_until_limit > 0) {
total_bytes_read_ = closest_limit;
input_->Skip(bytes_until_limit);
}
return false;
}
total_bytes_read_ += count;
return input_->Skip(count);
}
bool CodedInputStream::GetDirectBufferPointer(const void** data, int* size) {
if (BufferSize() == 0 && !Refresh()) return false;
*data = buffer_;
*size = BufferSize();
return true;
}
bool CodedInputStream::ReadRaw(void* buffer, int size) {
return InternalReadRawInline(buffer, size);
}
bool CodedInputStream::ReadString(string* buffer, int size) {
if (size < 0) return false; // security: size is often user-supplied
return InternalReadStringInline(buffer, size);
}
bool CodedInputStream::ReadStringFallback(string* buffer, int size) {
if (!buffer->empty()) {
buffer->clear();
}
int closest_limit = std::min(current_limit_, total_bytes_limit_);
if (closest_limit != INT_MAX) {
int bytes_to_limit = closest_limit - CurrentPosition();
if (bytes_to_limit > 0 && size > 0 && size <= bytes_to_limit) {
buffer->reserve(size);
}
}
int current_buffer_size;
while ((current_buffer_size = BufferSize()) < size) {
// Some STL implementations "helpfully" crash on buffer->append(NULL, 0).
if (current_buffer_size != 0) {
// Note: string1.append(string2) is O(string2.size()) (as opposed to
// O(string1.size() + string2.size()), which would be bad).
buffer->append(reinterpret_cast<const char*>(buffer_),
current_buffer_size);
}
size -= current_buffer_size;
Advance(current_buffer_size);
if (!Refresh()) return false;
}
buffer->append(reinterpret_cast<const char*>(buffer_), size);
Advance(size);
return true;
}
bool CodedInputStream::ReadLittleEndian32Fallback(uint32* value) {
uint8 bytes[sizeof(*value)];
const uint8* ptr;
if (BufferSize() >= sizeof(*value)) {
// Fast path: Enough bytes in the buffer to read directly.
ptr = buffer_;
Advance(sizeof(*value));
} else {
// Slow path: Had to read past the end of the buffer.
if (!ReadRaw(bytes, sizeof(*value))) return false;
ptr = bytes;
}
ReadLittleEndian32FromArray(ptr, value);
return true;
}
bool CodedInputStream::ReadLittleEndian64Fallback(uint64* value) {
uint8 bytes[sizeof(*value)];
const uint8* ptr;
if (BufferSize() >= sizeof(*value)) {
// Fast path: Enough bytes in the buffer to read directly.
ptr = buffer_;
Advance(sizeof(*value));
} else {
// Slow path: Had to read past the end of the buffer.
if (!ReadRaw(bytes, sizeof(*value))) return false;
ptr = bytes;
}
ReadLittleEndian64FromArray(ptr, value);
return true;
}
namespace {
// Read a varint from the given buffer, write it to *value, and return a pair.
// The first part of the pair is true iff the read was successful. The second
// part is buffer + (number of bytes read). This function is always inlined,
// so returning a pair is costless.
GOOGLE_ATTRIBUTE_ALWAYS_INLINE ::std::pair<bool, const uint8*> ReadVarint32FromArray(
uint32 first_byte, const uint8* buffer,
uint32* value);
inline ::std::pair<bool, const uint8*> ReadVarint32FromArray(
uint32 first_byte, const uint8* buffer, uint32* value) {
// Fast path: We have enough bytes left in the buffer to guarantee that
// this read won't cross the end, so we can skip the checks.
GOOGLE_DCHECK_EQ(*buffer, first_byte);
GOOGLE_DCHECK_EQ(first_byte & 0x80, 0x80) << first_byte;
const uint8* ptr = buffer;
uint32 b;
uint32 result = first_byte - 0x80;
++ptr; // We just processed the first byte. Move on to the second.
b = *(ptr++); result += b << 7; if (!(b & 0x80)) goto done;
result -= 0x80 << 7;
b = *(ptr++); result += b << 14; if (!(b & 0x80)) goto done;
result -= 0x80 << 14;
b = *(ptr++); result += b << 21; if (!(b & 0x80)) goto done;
result -= 0x80 << 21;
b = *(ptr++); result += b << 28; if (!(b & 0x80)) goto done;
// "result -= 0x80 << 28" is irrevelant.
// If the input is larger than 32 bits, we still need to read it all
// and discard the high-order bits.
for (int i = 0; i < kMaxVarintBytes - kMaxVarint32Bytes; i++) {
b = *(ptr++); if (!(b & 0x80)) goto done;
}
// We have overrun the maximum size of a varint (10 bytes). Assume
// the data is corrupt.
return std::make_pair(false, ptr);
done:
*value = result;
return std::make_pair(true, ptr);
}
} // namespace
bool CodedInputStream::ReadVarint32Slow(uint32* value) {
// Directly invoke ReadVarint64Fallback, since we already tried to optimize
// for one-byte varints.
std::pair<uint64, bool> p = ReadVarint64Fallback();
*value = static_cast<uint32>(p.first);
return p.second;
}
int64 CodedInputStream::ReadVarint32Fallback(uint32 first_byte_or_zero) {
if (BufferSize() >= kMaxVarintBytes ||
// Optimization: We're also safe if the buffer is non-empty and it ends
// with a byte that would terminate a varint.
(buffer_end_ > buffer_ && !(buffer_end_[-1] & 0x80))) {
GOOGLE_DCHECK_NE(first_byte_or_zero, 0)
<< "Caller should provide us with *buffer_ when buffer is non-empty";
uint32 temp;
::std::pair<bool, const uint8*> p =
ReadVarint32FromArray(first_byte_or_zero, buffer_, &temp);
if (!p.first) return -1;
buffer_ = p.second;
return temp;
} else {
// Really slow case: we will incur the cost of an extra function call here,
// but moving this out of line reduces the size of this function, which
// improves the common case. In micro benchmarks, this is worth about 10-15%
uint32 temp;
return ReadVarint32Slow(&temp) ? static_cast<int64>(temp) : -1;
}
}
uint32 CodedInputStream::ReadTagSlow() {
if (buffer_ == buffer_end_) {
// Call refresh.
if (!Refresh()) {
// Refresh failed. Make sure that it failed due to EOF, not because
// we hit total_bytes_limit_, which, unlike normal limits, is not a
// valid place to end a message.
int current_position = total_bytes_read_ - buffer_size_after_limit_;
if (current_position >= total_bytes_limit_) {
// Hit total_bytes_limit_. But if we also hit the normal limit,
// we're still OK.
legitimate_message_end_ = current_limit_ == total_bytes_limit_;
} else {
legitimate_message_end_ = true;
}
return 0;
}
}
// For the slow path, just do a 64-bit read. Try to optimize for one-byte tags
// again, since we have now refreshed the buffer.
uint64 result = 0;
if (!ReadVarint64(&result)) return 0;
return static_cast<uint32>(result);
}
uint32 CodedInputStream::ReadTagFallback(uint32 first_byte_or_zero) {
const int buf_size = BufferSize();
if (buf_size >= kMaxVarintBytes ||
// Optimization: We're also safe if the buffer is non-empty and it ends
// with a byte that would terminate a varint.
(buf_size > 0 && !(buffer_end_[-1] & 0x80))) {
GOOGLE_DCHECK_EQ(first_byte_or_zero, buffer_[0]);
if (first_byte_or_zero == 0) {
++buffer_;
return 0;
}
uint32 tag;
::std::pair<bool, const uint8*> p =
ReadVarint32FromArray(first_byte_or_zero, buffer_, &tag);
if (!p.first) {
return 0;
}
buffer_ = p.second;
return tag;
} else {
// We are commonly at a limit when attempting to read tags. Try to quickly
// detect this case without making another function call.
if ((buf_size == 0) &&
((buffer_size_after_limit_ > 0) ||
(total_bytes_read_ == current_limit_)) &&
// Make sure that the limit we hit is not total_bytes_limit_, since
// in that case we still need to call Refresh() so that it prints an
// error.
total_bytes_read_ - buffer_size_after_limit_ < total_bytes_limit_) {
// We hit a byte limit.
legitimate_message_end_ = true;
return 0;
}
return ReadTagSlow();
}
}
bool CodedInputStream::ReadVarint64Slow(uint64* value) {
// Slow path: This read might cross the end of the buffer, so we
// need to check and refresh the buffer if and when it does.
uint64 result = 0;
int count = 0;
uint32 b;
do {
if (count == kMaxVarintBytes) return false;
while (buffer_ == buffer_end_) {
if (!Refresh()) return false;
}
b = *buffer_;
result |= static_cast<uint64>(b & 0x7F) << (7 * count);
Advance(1);
++count;
} while (b & 0x80);
*value = result;
return true;
}
std::pair<uint64, bool> CodedInputStream::ReadVarint64Fallback() {
if (BufferSize() >= kMaxVarintBytes ||
// Optimization: We're also safe if the buffer is non-empty and it ends
// with a byte that would terminate a varint.
(buffer_end_ > buffer_ && !(buffer_end_[-1] & 0x80))) {
// Fast path: We have enough bytes left in the buffer to guarantee that
// this read won't cross the end, so we can skip the checks.
const uint8* ptr = buffer_;
uint32 b;
// Splitting into 32-bit pieces gives better performance on 32-bit
// processors.
uint32 part0 = 0, part1 = 0, part2 = 0;
b = *(ptr++); part0 = b ; if (!(b & 0x80)) goto done;
part0 -= 0x80;
b = *(ptr++); part0 += b << 7; if (!(b & 0x80)) goto done;
part0 -= 0x80 << 7;
b = *(ptr++); part0 += b << 14; if (!(b & 0x80)) goto done;
part0 -= 0x80 << 14;
b = *(ptr++); part0 += b << 21; if (!(b & 0x80)) goto done;
part0 -= 0x80 << 21;
b = *(ptr++); part1 = b ; if (!(b & 0x80)) goto done;
part1 -= 0x80;
b = *(ptr++); part1 += b << 7; if (!(b & 0x80)) goto done;
part1 -= 0x80 << 7;
b = *(ptr++); part1 += b << 14; if (!(b & 0x80)) goto done;
part1 -= 0x80 << 14;
b = *(ptr++); part1 += b << 21; if (!(b & 0x80)) goto done;
part1 -= 0x80 << 21;
b = *(ptr++); part2 = b ; if (!(b & 0x80)) goto done;
part2 -= 0x80;
b = *(ptr++); part2 += b << 7; if (!(b & 0x80)) goto done;
// "part2 -= 0x80 << 7" is irrelevant because (0x80 << 7) << 56 is 0.
// We have overrun the maximum size of a varint (10 bytes). The data
// must be corrupt.
return std::make_pair(0, false);
done:
Advance(ptr - buffer_);
return std::make_pair((static_cast<uint64>(part0)) |
(static_cast<uint64>(part1) << 28) |
(static_cast<uint64>(part2) << 56),
true);
} else {
uint64 temp;
bool success = ReadVarint64Slow(&temp);
return std::make_pair(temp, success);
}
}
bool CodedInputStream::Refresh() {
GOOGLE_DCHECK_EQ(0, BufferSize());
if (buffer_size_after_limit_ > 0 || overflow_bytes_ > 0 ||
total_bytes_read_ == current_limit_) {
// We've hit a limit. Stop.
int current_position = total_bytes_read_ - buffer_size_after_limit_;
if (current_position >= total_bytes_limit_ &&
total_bytes_limit_ != current_limit_) {
// Hit total_bytes_limit_.
PrintTotalBytesLimitError();
}
return false;
}
if (total_bytes_warning_threshold_ >= 0 &&
total_bytes_read_ >= total_bytes_warning_threshold_) {
GOOGLE_LOG(WARNING) << "Reading dangerously large protocol message. If the "
"message turns out to be larger than "
<< total_bytes_limit_ << " bytes, parsing will be halted "
"for security reasons. To increase the limit (or to "
"disable these warnings), see "
"CodedInputStream::SetTotalBytesLimit() in "
"google/protobuf/io/coded_stream.h.";
// Don't warn again for this stream, and print total size at the end.
total_bytes_warning_threshold_ = -2;
}
const void* void_buffer;
int buffer_size;
if (NextNonEmpty(input_, &void_buffer, &buffer_size)) {
buffer_ = reinterpret_cast<const uint8*>(void_buffer);
buffer_end_ = buffer_ + buffer_size;
GOOGLE_CHECK_GE(buffer_size, 0);
if (total_bytes_read_ <= INT_MAX - buffer_size) {
total_bytes_read_ += buffer_size;
} else {
// Overflow. Reset buffer_end_ to not include the bytes beyond INT_MAX.
// We can't get that far anyway, because total_bytes_limit_ is guaranteed
// to be less than it. We need to keep track of the number of bytes
// we discarded, though, so that we can call input_->BackUp() to back
// up over them on destruction.
// The following line is equivalent to:
// overflow_bytes_ = total_bytes_read_ + buffer_size - INT_MAX;
// except that it avoids overflows. Signed integer overflow has
// undefined results according to the C standard.
overflow_bytes_ = total_bytes_read_ - (INT_MAX - buffer_size);
buffer_end_ -= overflow_bytes_;
total_bytes_read_ = INT_MAX;
}
RecomputeBufferLimits();
return true;
} else {
buffer_ = NULL;
buffer_end_ = NULL;
return false;
}
}
// CodedOutputStream =================================================
CodedOutputStream::CodedOutputStream(ZeroCopyOutputStream* output)
: output_(output),
buffer_(NULL),
buffer_size_(0),
total_bytes_(0),
had_error_(false),
aliasing_enabled_(false) {
// Eagerly Refresh() so buffer space is immediately available.
Refresh();
// The Refresh() may have failed. If the client doesn't write any data,
// though, don't consider this an error. If the client does write data, then
// another Refresh() will be attempted and it will set the error once again.
had_error_ = false;
}
CodedOutputStream::CodedOutputStream(ZeroCopyOutputStream* output,
bool do_eager_refresh)
: output_(output),
buffer_(NULL),
buffer_size_(0),
total_bytes_(0),
had_error_(false),
aliasing_enabled_(false) {
if (do_eager_refresh) {
// Eagerly Refresh() so buffer space is immediately available.
Refresh();
// The Refresh() may have failed. If the client doesn't write any data,
// though, don't consider this an error. If the client does write data, then
// another Refresh() will be attempted and it will set the error once again.
had_error_ = false;
}
}
CodedOutputStream::~CodedOutputStream() {
Trim();
}
void CodedOutputStream::Trim() {
if (buffer_size_ > 0) {
output_->BackUp(buffer_size_);
total_bytes_ -= buffer_size_;
buffer_size_ = 0;
buffer_ = NULL;
}
}
bool CodedOutputStream::Skip(int count) {
if (count < 0) return false;
while (count > buffer_size_) {
count -= buffer_size_;
if (!Refresh()) return false;
}
Advance(count);
return true;
}
bool CodedOutputStream::GetDirectBufferPointer(void** data, int* size) {
if (buffer_size_ == 0 && !Refresh()) return false;
*data = buffer_;
*size = buffer_size_;
return true;
}
void CodedOutputStream::WriteRaw(const void* data, int size) {
while (buffer_size_ < size) {
memcpy(buffer_, data, buffer_size_);
size -= buffer_size_;
data = reinterpret_cast<const uint8*>(data) + buffer_size_;
if (!Refresh()) return;
}
memcpy(buffer_, data, size);
Advance(size);
}
uint8* CodedOutputStream::WriteRawToArray(
const void* data, int size, uint8* target) {
memcpy(target, data, size);
return target + size;
}
void CodedOutputStream::WriteAliasedRaw(const void* data, int size) {
if (size < buffer_size_
) {
WriteRaw(data, size);
} else {
Trim();
total_bytes_ += size;
had_error_ |= !output_->WriteAliasedRaw(data, size);
}
}
void CodedOutputStream::WriteLittleEndian32(uint32 value) {
uint8 bytes[sizeof(value)];
bool use_fast = buffer_size_ >= sizeof(value);
uint8* ptr = use_fast ? buffer_ : bytes;
WriteLittleEndian32ToArray(value, ptr);
if (use_fast) {
Advance(sizeof(value));
} else {
WriteRaw(bytes, sizeof(value));
}
}
void CodedOutputStream::WriteLittleEndian64(uint64 value) {
uint8 bytes[sizeof(value)];
bool use_fast = buffer_size_ >= sizeof(value);
uint8* ptr = use_fast ? buffer_ : bytes;
WriteLittleEndian64ToArray(value, ptr);
if (use_fast) {
Advance(sizeof(value));
} else {
WriteRaw(bytes, sizeof(value));
}
}
void CodedOutputStream::WriteVarint32SlowPath(uint32 value) {
uint8 bytes[kMaxVarint32Bytes];
uint8* target = &bytes[0];
uint8* end = WriteVarint32ToArray(value, target);
int size = end - target;
WriteRaw(bytes, size);
}
inline uint8* CodedOutputStream::WriteVarint64ToArrayInline(
uint64 value, uint8* target) {
// Splitting into 32-bit pieces gives better performance on 32-bit
// processors.
uint32 part0 = static_cast<uint32>(value );
uint32 part1 = static_cast<uint32>(value >> 28);
uint32 part2 = static_cast<uint32>(value >> 56);
int size;
// Here we can't really optimize for small numbers, since the value is
// split into three parts. Cheking for numbers < 128, for instance,
// would require three comparisons, since you'd have to make sure part1
// and part2 are zero. However, if the caller is using 64-bit integers,
// it is likely that they expect the numbers to often be very large, so
// we probably don't want to optimize for small numbers anyway. Thus,
// we end up with a hardcoded binary search tree...
if (part2 == 0) {
if (part1 == 0) {
if (part0 < (1 << 14)) {
if (part0 < (1 << 7)) {
size = 1; goto size1;
} else {
size = 2; goto size2;
}
} else {
if (part0 < (1 << 21)) {
size = 3; goto size3;
} else {
size = 4; goto size4;
}
}
} else {
if (part1 < (1 << 14)) {
if (part1 < (1 << 7)) {
size = 5; goto size5;
} else {
size = 6; goto size6;
}
} else {
if (part1 < (1 << 21)) {
size = 7; goto size7;
} else {
size = 8; goto size8;
}
}
}
} else {
if (part2 < (1 << 7)) {
size = 9; goto size9;
} else {
size = 10; goto size10;
}
}
GOOGLE_LOG(FATAL) << "Can't get here.";
size10: target[9] = static_cast<uint8>((part2 >> 7) | 0x80);
size9 : target[8] = static_cast<uint8>((part2 ) | 0x80);
size8 : target[7] = static_cast<uint8>((part1 >> 21) | 0x80);
size7 : target[6] = static_cast<uint8>((part1 >> 14) | 0x80);
size6 : target[5] = static_cast<uint8>((part1 >> 7) | 0x80);
size5 : target[4] = static_cast<uint8>((part1 ) | 0x80);
size4 : target[3] = static_cast<uint8>((part0 >> 21) | 0x80);
size3 : target[2] = static_cast<uint8>((part0 >> 14) | 0x80);
size2 : target[1] = static_cast<uint8>((part0 >> 7) | 0x80);
size1 : target[0] = static_cast<uint8>((part0 ) | 0x80);
target[size-1] &= 0x7F;
return target + size;
}
void CodedOutputStream::WriteVarint64(uint64 value) {
if (buffer_size_ >= kMaxVarintBytes) {
// Fast path: We have enough bytes left in the buffer to guarantee that
// this write won't cross the end, so we can skip the checks.
uint8* target = buffer_;
uint8* end = WriteVarint64ToArrayInline(value, target);
int size = end - target;
Advance(size);
} else {
// Slow path: This write might cross the end of the buffer, so we
// compose the bytes first then use WriteRaw().
uint8 bytes[kMaxVarintBytes];
int size = 0;
while (value > 0x7F) {
bytes[size++] = (static_cast<uint8>(value) & 0x7F) | 0x80;
value >>= 7;
}
bytes[size++] = static_cast<uint8>(value) & 0x7F;
WriteRaw(bytes, size);
}
}
uint8* CodedOutputStream::WriteVarint64ToArray(
uint64 value, uint8* target) {
return WriteVarint64ToArrayInline(value, target);
}
bool CodedOutputStream::Refresh() {
void* void_buffer;
if (output_->Next(&void_buffer, &buffer_size_)) {
buffer_ = reinterpret_cast<uint8*>(void_buffer);
total_bytes_ += buffer_size_;
return true;
} else {
buffer_ = NULL;
buffer_size_ = 0;
had_error_ = true;
return false;
}
}
int CodedOutputStream::VarintSize32Fallback(uint32 value) {
if (value < (1 << 7)) {
return 1;
} else if (value < (1 << 14)) {
return 2;
} else if (value < (1 << 21)) {
return 3;
} else if (value < (1 << 28)) {
return 4;
} else {
return 5;
}
}
int CodedOutputStream::VarintSize64(uint64 value) {
if (value < (1ull << 35)) {
if (value < (1ull << 7)) {
return 1;
} else if (value < (1ull << 14)) {
return 2;
} else if (value < (1ull << 21)) {
return 3;
} else if (value < (1ull << 28)) {
return 4;
} else {
return 5;
}
} else {
if (value < (1ull << 42)) {
return 6;
} else if (value < (1ull << 49)) {
return 7;
} else if (value < (1ull << 56)) {
return 8;
} else if (value < (1ull << 63)) {
return 9;
} else {
return 10;
}
}
}
uint8* CodedOutputStream::WriteStringWithSizeToArray(const string& str,
uint8* target) {
GOOGLE_DCHECK_LE(str.size(), kuint32max);
target = WriteVarint32ToArray(str.size(), target);
return WriteStringToArray(str, target);
}
} // namespace io
} // namespace protobuf
} // namespace google