1 files changed, 93 insertions, 0 deletions
diff --git a/src/core/lib/compression/stream_compression_identity.cc b/src/core/lib/compression/stream_compression_identity.cc
new file mode 100644
index 0000000000..9b2e6062e1
--- /dev/null
+++ b/src/core/lib/compression/stream_compression_identity.cc
@@ -0,0 +1,93 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * 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 <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include "src/core/lib/compression/stream_compression_identity.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
+#include "src/core/lib/slice/slice_internal.h"
+
+#define OUTPUT_BLOCK_SIZE (1024)
+
+/* Singleton context used for all identity streams. */
+static grpc_stream_compression_context identity_ctx = {
+    &grpc_stream_compression_identity_vtable};
+
+static void grpc_stream_compression_pass_through(grpc_slice_buffer *in,
+                                                 grpc_slice_buffer *out,
+                                                 size_t *output_size,
+                                                 size_t max_output_size) {
+  if (max_output_size >= in->length) {
+    if (output_size) {
+      *output_size = in->length;
+    }
+    grpc_slice_buffer_move_into(in, out);
+  } else {
+    if (output_size) {
+      *output_size = max_output_size;
+    }
+    grpc_slice_buffer_move_first(in, max_output_size, out);
+  }
+}
+
+static bool grpc_stream_compress_identity(grpc_stream_compression_context *ctx,
+                                          grpc_slice_buffer *in,
+                                          grpc_slice_buffer *out,
+                                          size_t *output_size,
+                                          size_t max_output_size,
+                                          grpc_stream_compression_flush flush) {
+  if (ctx == NULL) {
+    return false;
+  }
+  grpc_stream_compression_pass_through(in, out, output_size, max_output_size);
+  return true;
+}
+
+static bool grpc_stream_decompress_identity(
+    grpc_stream_compression_context *ctx, grpc_slice_buffer *in,
+    grpc_slice_buffer *out, size_t *output_size, size_t max_output_size,
+    bool *end_of_context) {
+  if (ctx == NULL) {
+    return false;
+  }
+  grpc_stream_compression_pass_through(in, out, output_size, max_output_size);
+  if (end_of_context) {
+    *end_of_context = false;
+  }
+  return true;
+}
+
+static grpc_stream_compression_context *
+grpc_stream_compression_context_create_identity(
+    grpc_stream_compression_method method) {
+  GPR_ASSERT(method == GRPC_STREAM_COMPRESSION_IDENTITY_COMPRESS ||
+             method == GRPC_STREAM_COMPRESSION_IDENTITY_DECOMPRESS);
+  /* No context needed in this case. Use fake context instead. */
+  return (grpc_stream_compression_context *)&identity_ctx;
+}
+
+static void grpc_stream_compression_context_destroy_identity(
+    grpc_stream_compression_context *ctx) {
+  return;
+}
+
+const grpc_stream_compression_vtable grpc_stream_compression_identity_vtable = {
+    grpc_stream_compress_identity, grpc_stream_decompress_identity,
+    grpc_stream_compression_context_create_identity,
+    grpc_stream_compression_context_destroy_identity};