Initial checkin of gRPC to third_party/

third_party/grpc/src/core/transport/chttp2/varint.h

Index: third_party/grpc/src/core/transport/chttp2/varint.h
diff --git a/third_party/grpc/src/core/transport/chttp2/varint.h b/third_party/grpc/src/core/transport/chttp2/varint.h
new file mode 100644
index 0000000000000000000000000000000000000000..2d92b6693e9c87f28dbd506a2da78e8606edfd22
--- /dev/null
+++ b/third_party/grpc/src/core/transport/chttp2/varint.h
@@ -0,0 +1,75 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * 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.
+ *
+ */
+
+#ifndef GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_VARINT_H
+#define GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_VARINT_H
+
+#include <grpc/support/port_platform.h>
+
+/* Helpers for hpack varint encoding */
+
+/* length of a value that needs varint tail encoding (it's bigger than can be
+   bitpacked into the opcode byte) - returned value includes the length of the
+   opcode byte */
+uint32_t grpc_chttp2_hpack_varint_length(uint32_t tail_value);
+
+void grpc_chttp2_hpack_write_varint_tail(uint32_t tail_value, uint8_t* target,
+                                         uint32_t tail_length);
+
+/* maximum value that can be bitpacked with the opcode if the opcode has a
+   prefix
+   of length prefix_bits */
+#define GRPC_CHTTP2_MAX_IN_PREFIX(prefix_bits) \
+  ((uint32_t)((1 << (8 - (prefix_bits))) - 1))
+
+/* length required to bitpack a value */
+#define GRPC_CHTTP2_VARINT_LENGTH(n, prefix_bits) \
+  ((n) < GRPC_CHTTP2_MAX_IN_PREFIX(prefix_bits)   \
+       ? 1u                                       \
+       : grpc_chttp2_hpack_varint_length(         \
+             (n)-GRPC_CHTTP2_MAX_IN_PREFIX(prefix_bits)))
+
+#define GRPC_CHTTP2_WRITE_VARINT(n, prefix_bits, prefix_or, target, length)   \
+  do {                                                                        \
+    uint8_t* tgt = target;                                                    \
+    if ((length) == 1u) {                                                     \
+      (tgt)[0] = (uint8_t)((prefix_or) | (n));                                \
+    } else {                                                                  \
+      (tgt)[0] =                                                              \
+          (prefix_or) | (uint8_t)GRPC_CHTTP2_MAX_IN_PREFIX(prefix_bits);      \
+      grpc_chttp2_hpack_write_varint_tail(                                    \
+          (n)-GRPC_CHTTP2_MAX_IN_PREFIX(prefix_bits), (tgt) + 1, (length)-1); \
+    }                                                                         \
+  } while (0)
+
+#endif /* GRPC_INTERNAL_CORE_TRANSPORT_CHTTP2_VARINT_H */