Initial preparations for CURL and Discord integration.

module/Vendor/WebSocketPP/websocketpp/extensions/extension.hpp

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. 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 the WebSocket++ Project 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 PETER THORSON 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 WEBSOCKETPP_EXTENSION_HPP
+#define WEBSOCKETPP_EXTENSION_HPP
+
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/system_error.hpp>
+
+#include <string>
+#include <vector>
+
+namespace websocketpp {
+
+/**
+ * Some generic information about extensions
+ *
+ * Each extension object has an implemented flag. It can be retrieved by calling
+ * is_implemented(). This compile time flag indicates whether or not the object
+ * in question actually implements the extension or if it is a placeholder stub
+ *
+ * Each extension object also has an enabled flag. It can be retrieved by
+ * calling is_enabled(). This runtime flag indicates whether or not the
+ * extension has been negotiated for this connection.
+ */
+namespace extensions {
+
+namespace error {
+enum value {
+    /// Catch all
+    general = 1,
+
+    /// Extension disabled
+    disabled
+};
+
+class category : public lib::error_category {
+public:
+    category() {}
+
+    const char *name() const _WEBSOCKETPP_NOEXCEPT_TOKEN_ {
+        return "websocketpp.extension";
+    }
+
+    std::string message(int value) const {
+        switch(value) {
+            case general:
+                return "Generic extension error";
+            case disabled:
+                return "Use of methods from disabled extension";
+            default:
+                return "Unknown permessage-compress error";
+        }
+    }
+};
+
+inline lib::error_category const & get_category() {
+    static category instance;
+    return instance;
+}
+
+inline lib::error_code make_error_code(error::value e) {
+    return lib::error_code(static_cast<int>(e), get_category());
+}
+
+} // namespace error
+} // namespace extensions
+} // namespace websocketpp
+
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_START_
+template<> struct is_error_code_enum
+    <websocketpp::extensions::error::value>
+{
+    static const bool value = true;
+};
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_END_
+
+#endif // WEBSOCKETPP_EXTENSION_HPP

module/Vendor/WebSocketPP/websocketpp/extensions/permessage_deflate/disabled.hpp

@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) 2014, Peter Thorson. 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 the WebSocket++ Project 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 PETER THORSON 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 WEBSOCKETPP_EXTENSION_PERMESSAGE_DEFLATE_DISABLED_HPP
+#define WEBSOCKETPP_EXTENSION_PERMESSAGE_DEFLATE_DISABLED_HPP
+
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/stdint.hpp>
+#include <websocketpp/common/system_error.hpp>
+
+#include <websocketpp/http/constants.hpp>
+#include <websocketpp/extensions/extension.hpp>
+
+#include <map>
+#include <string>
+#include <utility>
+
+namespace websocketpp {
+namespace extensions {
+namespace permessage_deflate {
+
+/// Stub class for use when disabling permessage_deflate extension
+/**
+ * This class is a stub that implements the permessage_deflate interface
+ * with minimal dependencies. It is used to disable permessage_deflate
+ * functionality at compile time without loading any unnecessary code.
+ */
+template <typename config>
+class disabled {
+    typedef std::pair<lib::error_code,std::string> err_str_pair;
+
+public:
+    /// Negotiate extension
+    /**
+     * The disabled extension always fails the negotiation with a disabled
+     * error.
+     *
+     * @param offer Attribute from client's offer
+     * @return Status code and value to return to remote endpoint
+     */
+    err_str_pair negotiate(http::attribute_list const &) {
+        return make_pair(make_error_code(error::disabled),std::string());
+    }
+
+    /// Initialize state
+    /**
+     * For the disabled extension state initialization is a no-op.
+     *
+     * @param is_server True to initialize as a server, false for a client.
+     * @return A code representing the error that occurred, if any
+     */
+    lib::error_code init(bool) {
+        return lib::error_code();
+    }
+
+    /// Returns true if the extension is capable of providing
+    /// permessage_deflate functionality
+    bool is_implemented() const {
+        return false;
+    }
+
+    /// Returns true if permessage_deflate functionality is active for this
+    /// connection
+    bool is_enabled() const {
+        return false;
+    }
+
+    /// Generate extension offer
+    /**
+     * Creates an offer string to include in the Sec-WebSocket-Extensions
+     * header of outgoing client requests.
+     *
+     * @return A WebSocket extension offer string for this extension
+     */
+    std::string generate_offer() const {
+        return "";
+    }
+
+    /// Compress bytes
+    /**
+     * @param [in] in String to compress
+     * @param [out] out String to append compressed bytes to
+     * @return Error or status code
+     */
+    lib::error_code compress(std::string const &, std::string &) {
+        return make_error_code(error::disabled);
+    }
+
+    /// Decompress bytes
+    /**
+     * @param buf Byte buffer to decompress
+     * @param len Length of buf
+     * @param out String to append decompressed bytes to
+     * @return Error or status code
+     */
+    lib::error_code decompress(uint8_t const *, size_t, std::string &) {
+        return make_error_code(error::disabled);
+    }
+};
+
+} // namespace permessage_deflate
+} // namespace extensions
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_EXTENSION_PERMESSAGE_DEFLATE_DISABLED_HPP

module/Vendor/WebSocketPP/websocketpp/extensions/permessage_deflate/enabled.hpp

@@ -0,0 +1,817 @@
+/*
+ * Copyright (c) 2015, Peter Thorson. 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 the WebSocket++ Project 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 PETER THORSON 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 WEBSOCKETPP_PROCESSOR_EXTENSION_PERMESSAGEDEFLATE_HPP
+#define WEBSOCKETPP_PROCESSOR_EXTENSION_PERMESSAGEDEFLATE_HPP
+
+
+#include <websocketpp/common/cpp11.hpp>
+#include <websocketpp/common/memory.hpp>
+#include <websocketpp/common/platforms.hpp>
+#include <websocketpp/common/stdint.hpp>
+#include <websocketpp/common/system_error.hpp>
+#include <websocketpp/error.hpp>
+
+#include <websocketpp/extensions/extension.hpp>
+
+#include "zlib.h"
+
+#include <algorithm>
+#include <string>
+#include <vector>
+
+namespace websocketpp {
+namespace extensions {
+
+/// Implementation of RFC 7692, the permessage-deflate WebSocket extension
+/**
+ * ### permessage-deflate interface
+ *
+ * **init**\n
+ * `lib::error_code init(bool is_server)`\n
+ * Performs initialization
+ *
+ * **is_implimented**\n
+ * `bool is_implimented()`\n
+ * Returns whether or not the object impliments the extension or not
+ *
+ * **is_enabled**\n
+ * `bool is_enabled()`\n
+ * Returns whether or not the extension was negotiated for the current
+ * connection
+ *
+ * **generate_offer**\n
+ * `std::string generate_offer() const`\n
+ * Create an extension offer string based on local policy
+ *
+ * **validate_response**\n
+ * `lib::error_code validate_response(http::attribute_list const & response)`\n
+ * Negotiate the parameters of extension use
+ *
+ * **negotiate**\n
+ * `err_str_pair negotiate(http::attribute_list const & attributes)`\n
+ * Negotiate the parameters of extension use
+ *
+ * **compress**\n
+ * `lib::error_code compress(std::string const & in, std::string & out)`\n
+ * Compress the bytes in `in` and append them to `out`
+ *
+ * **decompress**\n
+ * `lib::error_code decompress(uint8_t const * buf, size_t len, std::string &
+ * out)`\n
+ * Decompress `len` bytes from `buf` and append them to string `out`
+ */
+namespace permessage_deflate {
+
+/// Permessage deflate error values
+namespace error {
+enum value {
+    /// Catch all
+    general = 1,
+
+    /// Invalid extension attributes
+    invalid_attributes,
+
+    /// Invalid extension attribute value
+    invalid_attribute_value,
+
+    /// Invalid megotiation mode
+    invalid_mode,
+
+    /// Unsupported extension attributes
+    unsupported_attributes,
+
+    /// Invalid value for max_window_bits
+    invalid_max_window_bits,
+
+    /// ZLib Error
+    zlib_error,
+
+    /// Uninitialized
+    uninitialized,
+};
+
+/// Permessage-deflate error category
+class category : public lib::error_category {
+public:
+    category() {}
+
+    char const * name() const _WEBSOCKETPP_NOEXCEPT_TOKEN_ {
+        return "websocketpp.extension.permessage-deflate";
+    }
+
+    std::string message(int value) const {
+        switch(value) {
+            case general:
+                return "Generic permessage-compress error";
+            case invalid_attributes:
+                return "Invalid extension attributes";
+            case invalid_attribute_value:
+                return "Invalid extension attribute value";
+            case invalid_mode:
+                return "Invalid permessage-deflate negotiation mode";
+            case unsupported_attributes:
+                return "Unsupported extension attributes";
+            case invalid_max_window_bits:
+                return "Invalid value for max_window_bits";
+            case zlib_error:
+                return "A zlib function returned an error";
+            case uninitialized:
+                return "Deflate extension must be initialized before use";
+            default:
+                return "Unknown permessage-compress error";
+        }
+    }
+};
+
+/// Get a reference to a static copy of the permessage-deflate error category
+inline lib::error_category const & get_category() {
+    static category instance;
+    return instance;
+}
+
+/// Create an error code in the permessage-deflate category
+inline lib::error_code make_error_code(error::value e) {
+    return lib::error_code(static_cast<int>(e), get_category());
+}
+
+} // namespace error
+} // namespace permessage_deflate
+} // namespace extensions
+} // namespace websocketpp
+
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_START_
+template<> struct is_error_code_enum
+    <websocketpp::extensions::permessage_deflate::error::value>
+{
+    static bool const value = true;
+};
+_WEBSOCKETPP_ERROR_CODE_ENUM_NS_END_
+namespace websocketpp {
+namespace extensions {
+namespace permessage_deflate {
+
+/// Default value for server_max_window_bits as defined by RFC 7692
+static uint8_t const default_server_max_window_bits = 15;
+/// Minimum value for server_max_window_bits as defined by RFC 7692
+/**
+ * NOTE: A value of 8 is not actually supported by zlib, the deflate
+ * library that WebSocket++ uses. To preserve backwards compatibility
+ * with RFC 7692 and previous versions of the library a value of 8
+ * is accepted by the library but will always be negotiated as 9.
+ */
+static uint8_t const min_server_max_window_bits = 8;
+/// Maximum value for server_max_window_bits as defined by RFC 7692
+static uint8_t const max_server_max_window_bits = 15;
+
+/// Default value for client_max_window_bits as defined by RFC 7692
+static uint8_t const default_client_max_window_bits = 15;
+/// Minimum value for client_max_window_bits as defined by RFC 7692
+/**
+ * NOTE: A value of 8 is not actually supported by zlib, the deflate
+ * library that WebSocket++ uses. To preserve backwards compatibility
+ * with RFC 7692 and previous versions of the library a value of 8
+ * is accepted by the library but will always be negotiated as 9.
+ */
+static uint8_t const min_client_max_window_bits = 8;
+/// Maximum value for client_max_window_bits as defined by RFC 7692
+static uint8_t const max_client_max_window_bits = 15;
+
+namespace mode {
+enum value {
+    /// Accept any value the remote endpoint offers
+    accept = 1,
+    /// Decline any value the remote endpoint offers. Insist on defaults.
+    decline,
+    /// Use the largest value common to both offers
+    largest,
+    /// Use the smallest value common to both offers
+    smallest
+};
+} // namespace mode
+
+template <typename config>
+class enabled {
+public:
+    enabled()
+      : m_enabled(false)
+      , m_server_no_context_takeover(false)
+      , m_client_no_context_takeover(false)
+      , m_server_max_window_bits(15)
+      , m_client_max_window_bits(15)
+      , m_server_max_window_bits_mode(mode::accept)
+      , m_client_max_window_bits_mode(mode::accept)
+      , m_initialized(false)
+      , m_compress_buffer_size(8192)
+    {
+        m_dstate.zalloc = Z_NULL;
+        m_dstate.zfree = Z_NULL;
+        m_dstate.opaque = Z_NULL;
+
+        m_istate.zalloc = Z_NULL;
+        m_istate.zfree = Z_NULL;
+        m_istate.opaque = Z_NULL;
+        m_istate.avail_in = 0;
+        m_istate.next_in = Z_NULL;
+    }
+
+    ~enabled() {
+        if (!m_initialized) {
+            return;
+        }
+
+        int ret = deflateEnd(&m_dstate);
+
+        if (ret != Z_OK) {
+            //std::cout << "error cleaning up zlib compression state"
+            //          << std::endl;
+        }
+
+        ret = inflateEnd(&m_istate);
+
+        if (ret != Z_OK) {
+            //std::cout << "error cleaning up zlib decompression state"
+            //          << std::endl;
+        }
+    }
+
+    /// Initialize zlib state
+    /**
+     * Note: this should be called *after* the negotiation methods. It will use
+     * information from the negotiation to determine how to initialize the zlib
+     * data structures.
+     *
+     * @todo memory level, strategy, etc are hardcoded
+     *
+     * @param is_server True to initialize as a server, false for a client.
+     * @return A code representing the error that occurred, if any
+     */
+    lib::error_code init(bool is_server) {
+        uint8_t deflate_bits;
+        uint8_t inflate_bits;
+
+        if (is_server) {
+            deflate_bits = m_server_max_window_bits;
+            inflate_bits = m_client_max_window_bits;
+        } else {
+            deflate_bits = m_client_max_window_bits;
+            inflate_bits = m_server_max_window_bits;
+        }
+
+        int ret = deflateInit2(
+            &m_dstate,
+            Z_DEFAULT_COMPRESSION,
+            Z_DEFLATED,
+            -1*deflate_bits,
+            4, // memory level 1-9
+            Z_DEFAULT_STRATEGY
+        );
+
+        if (ret != Z_OK) {
+            return make_error_code(error::zlib_error);
+        }
+
+        ret = inflateInit2(
+            &m_istate,
+            -1*inflate_bits
+        );
+
+        if (ret != Z_OK) {
+            return make_error_code(error::zlib_error);
+        }
+
+        m_compress_buffer.reset(new unsigned char[m_compress_buffer_size]);
+        m_decompress_buffer.reset(new unsigned char[m_compress_buffer_size]);
+        if ((m_server_no_context_takeover && is_server) ||
+            (m_client_no_context_takeover && !is_server))
+        {
+            m_flush = Z_FULL_FLUSH;
+        } else {
+            m_flush = Z_SYNC_FLUSH;
+        }
+        m_initialized = true;
+        return lib::error_code();
+    }
+
+    /// Test if this object implements the permessage-deflate specification
+    /**
+     * Because this object does implieent it, it will always return true.
+     *
+     * @return Whether or not this object implements permessage-deflate
+     */
+    bool is_implemented() const {
+        return true;
+    }
+
+    /// Test if the extension was negotiated for this connection
+    /**
+     * Retrieves whether or not this extension is in use based on the initial
+     * handshake extension negotiations.
+     *
+     * @return Whether or not the extension is in use
+     */
+    bool is_enabled() const {
+        return m_enabled;
+    }
+
+    /// Reset server's outgoing LZ77 sliding window for each new message
+    /**
+     * Enabling this setting will cause the server's compressor to reset the
+     * compression state (the LZ77 sliding window) for every message. This
+     * means that the compressor will not look back to patterns in previous
+     * messages to improve compression. This will reduce the compression
+     * efficiency for large messages somewhat and small messages drastically.
+     *
+     * This option may reduce server compressor memory usage and client
+     * decompressor memory usage.
+     * @todo Document to what extent memory usage will be reduced
+     *
+     * For clients, this option is dependent on server support. Enabling it
+     * via this method does not guarantee that it will be successfully
+     * negotiated, only that it will be requested.
+     *
+     * For servers, no client support is required. Enabling this option on a
+     * server will result in its use. The server will signal to clients that
+     * the option will be in use so they can optimize resource usage if they
+     * are able.
+     */
+    void enable_server_no_context_takeover() {
+        m_server_no_context_takeover = true;
+    }
+
+    /// Reset client's outgoing LZ77 sliding window for each new message
+    /**
+     * Enabling this setting will cause the client's compressor to reset the
+     * compression state (the LZ77 sliding window) for every message. This
+     * means that the compressor will not look back to patterns in previous
+     * messages to improve compression. This will reduce the compression
+     * efficiency for large messages somewhat and small messages drastically.
+     *
+     * This option may reduce client compressor memory usage and server
+     * decompressor memory usage.
+     * @todo Document to what extent memory usage will be reduced
+     *
+     * This option is supported by all compliant clients and servers. Enabling
+     * it via either endpoint should be sufficient to ensure it is used.
+     */
+    void enable_client_no_context_takeover() {
+        m_client_no_context_takeover = true;
+    }
+
+    /// Limit server LZ77 sliding window size
+    /**
+     * The bits setting is the base 2 logarithm of the maximum window size that
+     * the server must use to compress outgoing messages. The permitted range
+     * is 9 to 15 inclusive. 9 represents a 512 byte window and 15 a 32KiB
+     * window. The default setting is 15.
+     *
+     * Mode Options:
+     * - accept: Accept whatever the remote endpoint offers.
+     * - decline: Decline any offers to deviate from the defaults
+     * - largest: Accept largest window size acceptable to both endpoints
+     * - smallest: Accept smallest window size acceptiable to both endpoints
+     *
+     * This setting is dependent on server support. A client requesting this
+     * setting may be rejected by the server or have the exact value used
+     * adjusted by the server. A server may unilaterally set this value without
+     * client support.
+     *
+     * NOTE: The permessage-deflate spec specifies that a value of 8 is allowed.
+     * Prior to version 0.8.0 a value of 8 was also allowed by this library.
+     * zlib, the deflate compression library that WebSocket++ uses has always
+     * silently adjusted a value of 8 to 9. In recent versions of zlib (1.2.9 
+     * and greater) a value of 8 is now explicitly rejected. WebSocket++ 0.8.0
+     * continues to perform the 8->9 conversion for backwards compatibility
+     * purposes but this should be considered deprecated functionality.
+     *
+     * @param bits The size to request for the outgoing window size
+     * @param mode The mode to use for negotiating this parameter
+     * @return A status code
+     */
+    lib::error_code set_server_max_window_bits(uint8_t bits, mode::value mode) {
+        if (bits < min_server_max_window_bits || bits > max_server_max_window_bits) {
+            return error::make_error_code(error::invalid_max_window_bits);
+        }
+
+        // See note in doc comment above about what is happening here
+        if (bits == 8) {
+            bits = 9;
+        }
+
+        m_server_max_window_bits = bits;
+        m_server_max_window_bits_mode = mode;
+
+        return lib::error_code();
+    }
+
+    /// Limit client LZ77 sliding window size
+    /**
+     * The bits setting is the base 2 logarithm of the window size that the
+     * client must use to compress outgoing messages. The permitted range is 9
+     * to 15 inclusive. 9 represents a 512 byte window and 15 a 32KiB window.
+     * The default setting is 15.
+     *
+     * Mode Options:
+     * - accept: Accept whatever the remote endpoint offers.
+     * - decline: Decline any offers to deviate from the defaults
+     * - largest: Accept largest window size acceptable to both endpoints
+     * - smallest: Accept smallest window size acceptiable to both endpoints
+     *
+     * This setting is dependent on client support. A client may limit its own
+     * outgoing window size unilaterally. A server may only limit the client's
+     * window size if the remote client supports that feature.
+     *
+     * NOTE: The permessage-deflate spec specifies that a value of 8 is allowed.
+     * Prior to version 0.8.0 a value of 8 was also allowed by this library.
+     * zlib, the deflate compression library that WebSocket++ uses has always
+     * silently adjusted a value of 8 to 9. In recent versions of zlib (1.2.9 
+     * and greater) a value of 8 is now explicitly rejected. WebSocket++ 0.8.0
+     * continues to perform the 8->9 conversion for backwards compatibility
+     * purposes but this should be considered deprecated functionality.
+     *
+     * @param bits The size to request for the outgoing window size
+     * @param mode The mode to use for negotiating this parameter
+     * @return A status code
+     */
+    lib::error_code set_client_max_window_bits(uint8_t bits, mode::value mode) {
+        if (bits < min_client_max_window_bits || bits > max_client_max_window_bits) {
+            return error::make_error_code(error::invalid_max_window_bits);
+        }
+
+        // See note in doc comment above about what is happening here
+        if (bits == 8) {
+            bits = 9;
+        }
+
+        m_client_max_window_bits = bits;
+        m_client_max_window_bits_mode = mode;
+
+        return lib::error_code();
+    }
+
+    /// Generate extension offer
+    /**
+     * Creates an offer string to include in the Sec-WebSocket-Extensions
+     * header of outgoing client requests.
+     *
+     * @return A WebSocket extension offer string for this extension
+     */
+    std::string generate_offer() const {
+        // TODO: this should be dynamically generated based on user settings
+        return "permessage-deflate; client_no_context_takeover; client_max_window_bits";
+    }
+
+    /// Validate extension response
+    /**
+     * Confirm that the server has negotiated settings compatible with our
+     * original offer and apply those settings to the extension state.
+     *
+     * @param response The server response attribute list to validate
+     * @return Validation error or 0 on success
+     */
+    lib::error_code validate_offer(http::attribute_list const &) {
+        return lib::error_code();
+    }
+
+    /// Negotiate extension
+    /**
+     * Confirm that the client's extension negotiation offer has settings
+     * compatible with local policy. If so, generate a reply and apply those
+     * settings to the extension state.
+     *
+     * @param offer Attribute from client's offer
+     * @return Status code and value to return to remote endpoint
+     */
+    err_str_pair negotiate(http::attribute_list const & offer) {
+        err_str_pair ret;
+
+        http::attribute_list::const_iterator it;
+        for (it = offer.begin(); it != offer.end(); ++it) {
+            if (it->first == "server_no_context_takeover") {
+                negotiate_server_no_context_takeover(it->second,ret.first);
+            } else if (it->first == "client_no_context_takeover") {
+                negotiate_client_no_context_takeover(it->second,ret.first);
+            } else if (it->first == "server_max_window_bits") {
+                negotiate_server_max_window_bits(it->second,ret.first);
+            } else if (it->first == "client_max_window_bits") {
+                negotiate_client_max_window_bits(it->second,ret.first);
+            } else {
+                ret.first = make_error_code(error::invalid_attributes);
+            }
+
+            if (ret.first) {
+                break;
+            }
+        }
+
+        if (ret.first == lib::error_code()) {
+            m_enabled = true;
+            ret.second = generate_response();
+        }
+
+        return ret;
+    }
+
+    /// Compress bytes
+    /**
+     * @todo: avail_in/out is 32 bit, need to fix for cases of >32 bit frames
+     * on 64 bit machines.
+     *
+     * @param [in] in String to compress
+     * @param [out] out String to append compressed bytes to
+     * @return Error or status code
+     */
+    lib::error_code compress(std::string const & in, std::string & out) {
+        if (!m_initialized) {
+            return make_error_code(error::uninitialized);
+        }
+
+        size_t output;
+
+        if (in.empty()) {
+            uint8_t buf[6] = {0x02, 0x00, 0x00, 0x00, 0xff, 0xff};
+            out.append((char *)(buf),6);
+            return lib::error_code();
+        }
+
+        m_dstate.avail_in = in.size();
+        m_dstate.next_in = (unsigned char *)(const_cast<char *>(in.data()));
+
+        do {
+            // Output to local buffer
+            m_dstate.avail_out = m_compress_buffer_size;
+            m_dstate.next_out = m_compress_buffer.get();
+
+            deflate(&m_dstate, m_flush);
+
+            output = m_compress_buffer_size - m_dstate.avail_out;
+
+            out.append((char *)(m_compress_buffer.get()),output);
+        } while (m_dstate.avail_out == 0);
+
+        return lib::error_code();
+    }
+
+    /// Decompress bytes
+    /**
+     * @param buf Byte buffer to decompress
+     * @param len Length of buf
+     * @param out String to append decompressed bytes to
+     * @return Error or status code
+     */
+    lib::error_code decompress(uint8_t const * buf, size_t len, std::string &
+        out)
+    {
+        if (!m_initialized) {
+            return make_error_code(error::uninitialized);
+        }
+
+        int ret;
+
+        m_istate.avail_in = len;
+        m_istate.next_in = const_cast<unsigned char *>(buf);
+
+        do {
+            m_istate.avail_out = m_compress_buffer_size;
+            m_istate.next_out = m_decompress_buffer.get();
+
+            ret = inflate(&m_istate, Z_SYNC_FLUSH);
+
+            if (ret == Z_NEED_DICT || ret == Z_DATA_ERROR || ret == Z_MEM_ERROR) {
+                return make_error_code(error::zlib_error);
+            }
+
+            out.append(
+                reinterpret_cast<char *>(m_decompress_buffer.get()),
+                m_compress_buffer_size - m_istate.avail_out
+            );
+        } while (m_istate.avail_out == 0);
+
+        return lib::error_code();
+    }
+private:
+    /// Generate negotiation response
+    /**
+     * @return Generate extension negotiation reponse string to send to client
+     */
+    std::string generate_response() {
+        std::string ret = "permessage-deflate";
+
+        if (m_server_no_context_takeover) {
+            ret += "; server_no_context_takeover";
+        }
+
+        if (m_client_no_context_takeover) {
+            ret += "; client_no_context_takeover";
+        }
+
+        if (m_server_max_window_bits < default_server_max_window_bits) {
+            std::stringstream s;
+            s << int(m_server_max_window_bits);
+            ret += "; server_max_window_bits="+s.str();
+        }
+
+        if (m_client_max_window_bits < default_client_max_window_bits) {
+            std::stringstream s;
+            s << int(m_client_max_window_bits);
+            ret += "; client_max_window_bits="+s.str();
+        }
+
+        return ret;
+    }
+
+    /// Negotiate server_no_context_takeover attribute
+    /**
+     * @param [in] value The value of the attribute from the offer
+     * @param [out] ec A reference to the error code to return errors via
+     */
+    void negotiate_server_no_context_takeover(std::string const & value,
+        lib::error_code & ec)
+    {
+        if (!value.empty()) {
+            ec = make_error_code(error::invalid_attribute_value);
+            return;
+        }
+
+        m_server_no_context_takeover = true;
+    }
+
+    /// Negotiate client_no_context_takeover attribute
+    /**
+     * @param [in] value The value of the attribute from the offer
+     * @param [out] ec A reference to the error code to return errors via
+     */
+    void negotiate_client_no_context_takeover(std::string const & value,
+        lib::error_code & ec)
+    {
+        if (!value.empty()) {
+            ec = make_error_code(error::invalid_attribute_value);
+            return;
+        }
+
+        m_client_no_context_takeover = true;
+    }
+
+    /// Negotiate server_max_window_bits attribute
+    /**
+     * When this method starts, m_server_max_window_bits will contain the server's
+     * preferred value and m_server_max_window_bits_mode will contain the mode the
+     * server wants to use to for negotiation. `value` contains the value the
+     * client requested that we use.
+     *
+     * options:
+     * - decline (ignore value, offer our default instead)
+     * - accept (use the value requested by the client)
+     * - largest (use largest value acceptable to both)
+     * - smallest (use smallest possible value)
+     *
+     * NOTE: As a value of 8 is no longer explicitly supported by zlib but might
+     * be requested for negotiation by an older client/server, if the result of
+     * the negotiation would be to send a value of 8, a value of 9 is offered
+     * instead. This ensures that WebSocket++ will only ever negotiate connections
+     * with compression settings explicitly supported by zlib.
+     *
+     * @param [in] value The value of the attribute from the offer
+     * @param [out] ec A reference to the error code to return errors via
+     */
+    void negotiate_server_max_window_bits(std::string const & value,
+        lib::error_code & ec)
+    {
+        uint8_t bits = uint8_t(atoi(value.c_str()));
+
+        if (bits < min_server_max_window_bits || bits > max_server_max_window_bits) {
+            ec = make_error_code(error::invalid_attribute_value);
+            m_server_max_window_bits = default_server_max_window_bits;
+            return;
+        }
+
+        switch (m_server_max_window_bits_mode) {
+            case mode::decline:
+                m_server_max_window_bits = default_server_max_window_bits;
+                break;
+            case mode::accept:
+                m_server_max_window_bits = bits;
+                break;
+            case mode::largest:
+                m_server_max_window_bits = std::min(bits,m_server_max_window_bits);
+                break;
+            case mode::smallest:
+                m_server_max_window_bits = min_server_max_window_bits;
+                break;
+            default:
+                ec = make_error_code(error::invalid_mode);
+                m_server_max_window_bits = default_server_max_window_bits;
+        }
+
+        // See note in doc comment
+        if (m_server_max_window_bits == 8) {
+            m_server_max_window_bits = 9;
+        }
+    }
+
+    /// Negotiate client_max_window_bits attribute
+    /**
+     * When this method starts, m_client_max_window_bits and m_c2s_max_window_mode
+     * will contain the server's preferred values for window size and
+     * negotiation mode.
+     *
+     * options:
+     * - decline (ignore value, offer our default instead)
+     * - accept (use the value requested by the client)
+     * - largest (use largest value acceptable to both)
+     * - smallest (use smallest possible value)
+     *
+     * NOTE: As a value of 8 is no longer explicitly supported by zlib but might
+     * be requested for negotiation by an older client/server, if the result of
+     * the negotiation would be to send a value of 8, a value of 9 is offered
+     * instead. This ensures that WebSocket++ will only ever negotiate connections
+     * with compression settings explicitly supported by zlib.
+     *
+     * @param [in] value The value of the attribute from the offer
+     * @param [out] ec A reference to the error code to return errors via
+     */
+    void negotiate_client_max_window_bits(std::string const & value,
+            lib::error_code & ec)
+    {
+        uint8_t bits = uint8_t(atoi(value.c_str()));
+
+        if (value.empty()) {
+            bits = default_client_max_window_bits;
+        } else if (bits < min_client_max_window_bits ||
+                   bits > max_client_max_window_bits)
+        {
+            ec = make_error_code(error::invalid_attribute_value);
+            m_client_max_window_bits = default_client_max_window_bits;
+            return;
+        }
+
+        switch (m_client_max_window_bits_mode) {
+            case mode::decline:
+                m_client_max_window_bits = default_client_max_window_bits;
+                break;
+            case mode::accept:
+                m_client_max_window_bits = bits;
+                break;
+            case mode::largest:
+                m_client_max_window_bits = std::min(bits,m_client_max_window_bits);
+                break;
+            case mode::smallest:
+                m_client_max_window_bits = min_client_max_window_bits;
+                break;
+            default:
+                ec = make_error_code(error::invalid_mode);
+                m_client_max_window_bits = default_client_max_window_bits;
+        }
+
+        // See note in doc comment
+        if (m_client_max_window_bits == 8) {
+            m_client_max_window_bits = 9;
+        }
+    }
+
+    bool m_enabled;
+    bool m_server_no_context_takeover;
+    bool m_client_no_context_takeover;
+    uint8_t m_server_max_window_bits;
+    uint8_t m_client_max_window_bits;
+    mode::value m_server_max_window_bits_mode;
+    mode::value m_client_max_window_bits_mode;
+
+    bool m_initialized;
+    int m_flush;
+    size_t m_compress_buffer_size;
+    lib::unique_ptr_uchar_array m_compress_buffer;
+    lib::unique_ptr_uchar_array m_decompress_buffer;
+    z_stream m_dstate;
+    z_stream m_istate;
+};
+
+} // namespace permessage_deflate
+} // namespace extensions
+} // namespace websocketpp
+
+#endif // WEBSOCKETPP_PROCESSOR_EXTENSION_PERMESSAGEDEFLATE_HPP