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net/quic/crypto/cert_compressor.h

Index: net/quic/crypto/cert_compressor.h
diff --git a/net/quic/crypto/cert_compressor.h b/net/quic/crypto/cert_compressor.h
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+++ b/net/quic/crypto/cert_compressor.h
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+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef NET_QUIC_CRYPTO_CERT_COMPRESSOR_H_
+#define NET_QUIC_CRYPTO_CERT_COMPRESSOR_H_
+
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/strings/string_piece.h"
+#include "net/base/net_export.h"
+#include "net/quic/crypto/common_cert_set.h"
+#include "net/quic/crypto/crypto_protocol.h"
+
+namespace net {
+
+// CertCompressor provides functions for compressing and decompressing
+// certificate chains using three techniquies:
+//   1) The peer may provide a list of a 64-bit, FNV-1a hashes of certificates
+//      that they already have. In the event that one of them is to be
+//      compressed, it can be replaced with just the hash.
+//   2) The peer may provide a number of hashes that represent sets of
+//      pre-shared certificates. If one of those certificates is to be
+//      compressed, and it's known to the given CommonCertSet, then it can be
+//      replaced with a set hash and index.
+//   3) Otherwise the certificates are compressed with zlib using a pre-shared
+//      dictionary that consists of the certificates handled with the above
+//      methods and a small chunk of common substrings.
+class NET_EXPORT_PRIVATE CertCompressor {
+ public:
+  // CompressChain compresses the certificates in |certs| and returns a
+  // compressed representation. |common_set| contains the common certificate
+  // sets known locally and |client_common_set_hashes| contains the hashes of
+  // the common sets known to the peer. |client_cached| contains 64-bit, FNV-1a
+  // hashes of certificates that the peer already possesses.
+  static std::string CompressChain(const std::vector<std::string>& certs,
+                                   base::StringPiece client_common_set_hashes,
+                                   base::StringPiece client_cached,
+                                   CommonCertSet* common_set);
+
+  // DecompressChain decompresses the result of |CompressChain|, given in |in|,
+  // into a series of certificates that are written to |out_certs|.
+  // |cached_certs| contains certificates that the peer may have omitted and
+  // |common_set| contains the common certificate sets known locally.
+  static bool DecompressChain(base::StringPiece in,
+                              const std::vector<std::string>& cached_certs,
+                              CommonCertSet* common_set,
+                              std::vector<std::string>* out_certs);
+};
+
+}  // namespace net
+
+#endif  // NET_QUIC_CRYPTO_CERT_COMPRESSOR_H_