third_party/protobuf: Update to HEAD (83d681ee2c)

third_party/protobuf/src/google/protobuf/io/coded_stream.cc

Index: third_party/protobuf/src/google/protobuf/io/coded_stream.cc
diff --git a/third_party/protobuf/src/google/protobuf/io/coded_stream.cc b/third_party/protobuf/src/google/protobuf/io/coded_stream.cc
index d8354c1f9cef5d46543873e229852bffb178472e..93748ee3d8c49ea039b72bb78f569598e50d7cc8 100644
--- a/third_party/protobuf/src/google/protobuf/io/coded_stream.cc
+++ b/third_party/protobuf/src/google/protobuf/io/coded_stream.cc
@@ -376,6 +376,49 @@ inline ::std::pair<bool, const uint8*> ReadVarint32FromArray(
   return std::make_pair(true, ptr);
 }
 
+GOOGLE_ATTRIBUTE_ALWAYS_INLINE::std::pair<bool, const uint8*> ReadVarint64FromArray(
+    const uint8* buffer, uint64* value);
+inline ::std::pair<bool, const uint8*> ReadVarint64FromArray(
+    const uint8* buffer, uint64* value) {
+  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).  Assume
+  // the data is corrupt.
+  return std::make_pair(false, ptr);
+
+ done:
+  *value = (static_cast<uint64>(part0)) |
+           (static_cast<uint64>(part1) << 28) |
+           (static_cast<uint64>(part2) << 56);
+  return std::make_pair(true, ptr);
+}
+
 }  // namespace
 
 bool CodedInputStream::ReadVarint32Slow(uint32* value) {
@@ -408,6 +451,32 @@ int64 CodedInputStream::ReadVarint32Fallback(uint32 first_byte_or_zero) {
   }
 }
 
+int CodedInputStream::ReadVarintSizeAsIntSlow() {
+  // Directly invoke ReadVarint64Fallback, since we already tried to optimize
+  // for one-byte varints.
+  std::pair<uint64, bool> p = ReadVarint64Fallback();
+  if (!p.second || p.first > static_cast<uint64>(INT_MAX)) return -1;
+  return p.first;
+}
+
+int CodedInputStream::ReadVarintSizeAsIntFallback() {
+  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))) {
+    uint64 temp;
+    ::std::pair<bool, const uint8*> p = ReadVarint64FromArray(buffer_, &temp);
+    if (!p.first || temp > static_cast<uint64>(INT_MAX)) 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%
+    return ReadVarintSizeAsIntSlow();
+  }
+}
+
 uint32 CodedInputStream::ReadTagSlow() {
   if (buffer_ == buffer_end_) {
     // Call refresh.
@@ -480,9 +549,15 @@ bool CodedInputStream::ReadVarint64Slow(uint64* value) {
   uint32 b;
 
   do {
-    if (count == kMaxVarintBytes) return false;
+    if (count == kMaxVarintBytes) {
+      *value = 0;
+      return false;
+    }
     while (buffer_ == buffer_end_) {
-      if (!Refresh()) return false;
+      if (!Refresh()) {
+        *value = 0;
+        return false;
+      }
     }
     b = *buffer_;
     result |= static_cast<uint64>(b & 0x7F) << (7 * count);
@@ -499,47 +574,13 @@ std::pair<uint64, bool> CodedInputStream::ReadVarint64Fallback() {
       // 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);
+    uint64 temp;
+    ::std::pair<bool, const uint8*> p = ReadVarint64FromArray(buffer_, &temp);
+    if (!p.first) {
+      return std::make_pair(0, false);
+    }
+    buffer_ = p.second;
+    return std::make_pair(temp, true);
   } else {
     uint64 temp;
     bool success = ReadVarint64Slow(&temp);
@@ -566,13 +607,13 @@ bool CodedInputStream::Refresh() {
 
   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.";
+      GOOGLE_LOG(INFO) << "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;
@@ -614,13 +655,16 @@ bool CodedInputStream::Refresh() {
 
 // CodedOutputStream =================================================
 
+bool CodedOutputStream::default_serialization_deterministic_ = false;
+
 CodedOutputStream::CodedOutputStream(ZeroCopyOutputStream* output)
   : output_(output),
     buffer_(NULL),
     buffer_size_(0),
     total_bytes_(0),
     had_error_(false),
-    aliasing_enabled_(false) {
+    aliasing_enabled_(false),
+    serialization_deterministic_is_overridden_(false) {
   // Eagerly Refresh() so buffer space is immediately available.
   Refresh();
   // The Refresh() may have failed. If the client doesn't write any data,
@@ -636,7 +680,8 @@ CodedOutputStream::CodedOutputStream(ZeroCopyOutputStream* output,
     buffer_size_(0),
     total_bytes_(0),
     had_error_(false),
-    aliasing_enabled_(false) {
+    aliasing_enabled_(false),
+    serialization_deterministic_is_overridden_(false) {
   if (do_eager_refresh) {
     // Eagerly Refresh() so buffer space is immediately available.
     Refresh();
@@ -749,104 +794,12 @@ void CodedOutputStream::WriteVarint32SlowPath(uint32 value) {
   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);
+void CodedOutputStream::WriteVarint64SlowPath(uint64 value) {
+  uint8 bytes[kMaxVarintBytes];
+  uint8* target = &bytes[0];
+  uint8* end = WriteVarint64ToArray(value, target);
+  int size = end - target;
+  WriteRaw(bytes, size);
 }
 
 bool CodedOutputStream::Refresh() {
@@ -863,46 +816,23 @@ bool CodedOutputStream::Refresh() {
   }
 }
 
-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;
-  }
+size_t CodedOutputStream::VarintSize32Fallback(uint32 value) {
+  // This computes floor(log2(value)) / 7 + 1
+  // Use an explicit multiplication to implement the divide of
+  // a number in the 1..31 range.
+  GOOGLE_DCHECK_NE(0, value);  // This is enforced by our caller.
+
+  uint32 log2value = Bits::Log2FloorNonZero(value);
+  return static_cast<size_t>((log2value * 9 + 73) / 64);
 }
 
-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;
-    }
-  }
+size_t CodedOutputStream::VarintSize64(uint64 value) {
+  // This computes value == 0 ? 1 : floor(log2(value)) / 7 + 1
+  // Use an explicit multiplication to implement the divide of
+  // a number in the 1..63 range.
+  // Explicit OR 0x1 to avoid calling clz(0), which is undefined.
+  uint32 log2value = Bits::Log2FloorNonZero64(value | 0x1);
+  return static_cast<size_t>((log2value * 9 + 73) / 64);
 }
 
 uint8* CodedOutputStream::WriteStringWithSizeToArray(const string& str,