<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE erlref SYSTEM "erlref.dtd">

<erlref>
  <header>
    <copyright>
      <year>2003</year><year>2013</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      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.
    
    </legalnotice>

    <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>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>
    <code type="none"><![CDATA[
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'{}
    ]]></code>

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

  <funcs>
    <func>
      <name>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>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>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>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>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 
          <seealso marker="megaco#encode_actions">encode_actions/3</seealso>.
          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>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>

