Revert "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 93748ee3d8c49ea039b72bb78f569598e50d7cc8..d8354c1f9cef5d46543873e229852bffb178472e 100644
--- a/third_party/protobuf/src/google/protobuf/io/coded_stream.cc
+++ b/third_party/protobuf/src/google/protobuf/io/coded_stream.cc
@@ -376,49 +376,6 @@ 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) {
@@ -451,32 +408,6 @@ 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.
@@ -549,15 +480,9 @@ bool CodedInputStream::ReadVarint64Slow(uint64* value) {
   uint32 b;
 
   do {
-    if (count == kMaxVarintBytes) {
-      *value = 0;
-      return false;
-    }
+    if (count == kMaxVarintBytes) return false;
     while (buffer_ == buffer_end_) {
-      if (!Refresh()) {
-        *value = 0;
-        return false;
-      }
+      if (!Refresh()) return false;
     }
     b = *buffer_;
     result |= static_cast<uint64>(b & 0x7F) << (7 * count);
@@ -574,13 +499,47 @@ 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))) {
-    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);
+    // 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);
@@ -607,13 +566,13 @@ bool CodedInputStream::Refresh() {
 
   if (total_bytes_warning_threshold_ >= 0 &&
       total_bytes_read_ >= total_bytes_warning_threshold_) {
-      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.";
+      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;
@@ -655,16 +614,13 @@ 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),
-    serialization_deterministic_is_overridden_(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,
@@ -680,8 +636,7 @@ CodedOutputStream::CodedOutputStream(ZeroCopyOutputStream* output,
     buffer_size_(0),
     total_bytes_(0),
     had_error_(false),
-    aliasing_enabled_(false),
-    serialization_deterministic_is_overridden_(false) {
+    aliasing_enabled_(false) {
   if (do_eager_refresh) {
     // Eagerly Refresh() so buffer space is immediately available.
     Refresh();
@@ -794,12 +749,104 @@ void CodedOutputStream::WriteVarint32SlowPath(uint32 value) {
   WriteRaw(bytes, size);
 }
 
-void CodedOutputStream::WriteVarint64SlowPath(uint64 value) {
-  uint8 bytes[kMaxVarintBytes];
-  uint8* target = &bytes[0];
-  uint8* end = WriteVarint64ToArray(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() {
@@ -816,23 +863,46 @@ bool CodedOutputStream::Refresh() {
   }
 }
 
-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::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::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);
+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,