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<erlref>
  <header>
    <copyright>
      <year>2003</year><year>2020</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
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      Licensed under the Apache License, Version 2.0 (the "License");
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    <title>megaco_encoder</title>
    <prepared>Micael Karlberg</prepared>
    <responsible>Micael Karlberg</responsible>
    <docno></docno>
    <approved>Micael Karlberg</approved>
    <checked></checked>
    <date>2007-06-15</date>
    <rev>%VSN%</rev>
    <file>megaco_encoder.xml</file>
  </header>
  <module since="">megaco_encoder</module>
  <modulesummary>Megaco encoder behaviour.</modulesummary>
  <description>
    <p>The following functions should be exported from a 
      <c><![CDATA[megaco_encoder]]></c> callback module:</p>

  </description>

  <section>
    <title>DATA TYPES</title>
    <note>
      <p>Note that the actual definition of (some of) these records depend on
      the megaco protocol version used. For instance, the
      <c>'TransactionReply'</c> record
      has two more fields in version 3, so a simple erlang type definition
      cannot be made here. </p>
    </note>
    <code type="none"><![CDATA[
protocol_version() = integer()
segment_no()       = integer()
megaco_message() = #'MegacoMessage{}'
transaction() = {transactionRequest,     transaction_request()}      |
                {transactionPending,     transaction_reply()}        |
                {transactionReply,       transaction_pending()}      |
                {transactionResponseAck, transaction_response_ack()} |
                {segmentReply,           segment_reply()}
transaction_request() = #'TransactionRequest'{}
transaction_pending() = #'TransactionPending'{}
transaction_reply() = #'TransactionReply'{}
transaction_response_ack() = [transaction_ack()]
transaction_ack() = #'TransactionAck'{}
segment_reply() = #'SegmentReply'{}
action_request() = #'ActionRequest'{}
action_reply() = #'ActionReply'{}
command_request() = #'CommandRequest'{}
error_desc()   = #'ErrorDescriptor'{}
    ]]></code>

    <marker id="encode_message"></marker>
  </section>

  <funcs>
    <func>
      <name since="">Module:encode_message(EncodingConfig, Version, Message) -> {ok, Bin} | Error</name>
      <fsummary>Encode a megaco message.</fsummary>
      <type>
        <v>EncodingConfig = list()</v>
        <v>Version = integer()</v>
        <v>Message = megaco_message()</v>
        <v>Bin = binary()</v>
        <v>Error = term()</v>
      </type>
      <desc>
        <p>Encode a megaco message.</p>

	<marker id="decode_message"></marker>
      </desc>
    </func>

    <func>
      <name since="">Module:decode_message(EncodingConfig, Version, Bin) -> {ok, Message} | Error</name>
      <fsummary>Decode a megaco message.</fsummary>
      <type>
        <v>EncodingConfig = list()</v>
        <v>Version = integer() | dynamic</v>
        <v>Message = megaco_message()</v>
        <v>Bin = binary()</v>
        <v>Error = term()</v>
      </type>
      <desc>
        <p>Decode a megaco message. </p>
        <p>Note that if the Version argument is <c><![CDATA[dynamic]]></c>, the
          decoder should try to figure out the actual version from the
          message itself and then use the proper decoder, e.g. version 1.
          <br></br>If on the other hand the Version argument is an integer, 
          it means that this is the expected version of the message and 
          the decoder for that version should be used.</p>

	<marker id="decode_mini_message"></marker>
      </desc>
    </func>

    <func>
      <name since="">Module:decode_mini_message(EncodingConfig, Version, Bin) -> {ok, Message} | Error</name>
      <fsummary>Perform a minimal decode of a megaco message.</fsummary>
      <type>
        <v>EncodingConfig = list()</v>
        <v>Version = integer() | dynamic</v>
        <v>Message = megaco_message()</v>
        <v>Bin = binary()</v>
        <v>Error = term()</v>
      </type>
      <desc>
        <p>Perform a minimal decode of a megaco message. </p>
        <p>The purpose of this function is to do a minimal decode of
          Megaco message. A successfull result is a <c><![CDATA['MegacoMessage']]></c> 
          in which only version and mid has been initiated. This function 
          is used by the megaco_messenger module when the 
          <c><![CDATA[decode_message/3]]></c> function fails to figure out the mid 
          (the actual sender) of the message.</p>
        <p>Note again that a successfull decode only returns a
          partially initiated message.</p>

	<marker id="encode_transaction"></marker>
      </desc>
    </func>

    <func>
      <name since="">Module:encode_transaction(EncodingConfig, Version, Transaction) -> OK | Error</name>
      <fsummary>Encode a megaco transaction.</fsummary>
      <type>
        <v>EncodingConfig = list()</v>
        <v>Version = integer()</v>
        <v>Transaction = transaction()</v>
        <v>OK = {ok, Bin}</v>
        <v>Bin = binary()</v>
        <v>Error = {error, Reason}</v>
        <v>Reason = not_implemented | OtherReason</v>
        <v>OtherReason = term()</v>
      </type>
      <desc>
        <p>Encode a megaco transaction. If this, for whatever reason, 
          is not supported, the function should return the error reason 
          <c>not_implemented</c>. </p>

        <p>This functionality is used both when the transaction sender is 
          used and for segmentation. So, for either of those to work, this 
          function <em>must</em> be fully supported! </p>

	<marker id="encode_action_requests"></marker>
      </desc>
    </func>

    <func>
      <name since="">Module:encode_action_requests(EncodingConfig, Version, ARs) -> OK | Error</name>
      <fsummary>Encode megaco action requests.</fsummary>
      <type>
        <v>EncodingConfig = list()</v>
        <v>Version = integer()</v>
        <v>ARs = action_requests()</v>
        <v>action_requests() = [action_request()]</v>
        <v>OK = {ok, Bin}</v>
        <v>Bin = binary()</v>
        <v>Error = {error, Reason}</v>
        <v>Reason = not_implemented | OtherReason</v>
        <v>OtherReason = term()</v>
      </type>
      <desc>
        <p>Encode megaco action requests. This function is called when 
          the user calls the function 
          <seeerl marker="megaco#encode_actions">encode_actions/3</seeerl>.
          If that function is never used or if the codec cannot support this
          (the encoding of individual actions), then return with error reason 
          <c>not_implemented</c>. </p>

	<marker id="encode_action_reply"></marker>
      </desc>
    </func>

    <func>
      <name since="">Module:encode_action_reply(EncodingConfig, Version, AR) -> OK | Error</name>
      <fsummary>Encode a megaco action reply.</fsummary>
      <type>
        <v>EncodingConfig = list()</v>
        <v>Version = integer()</v>
        <v>AR = action_reply()</v>
        <v>OK = {ok, Bin}</v>
        <v>Bin = binary()</v>
        <v>Error = {error, Reason}</v>
        <v>Reason = not_implemented | OtherReason</v>
        <v>OtherReason = term()</v>
      </type>
      <desc>
        <p>Encode a megaco action reply. If this, for whatever reason, 
          is not supported, the function should return the error reason 
          <c>not_implemented</c>. </p>

        <p>This function is used when segmentation has been configured. 
          So, for this to work, this function <em>must</em> be fully 
          supported! </p>
      </desc>
    </func>

  </funcs>

</erlref>

