bytereplaycharsequence.html

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<a name="118" href="#118">118</a> <em>     * Random access to the backing file.</em>
<a name="119" href="#119">119</a> <em>     */</em>
<a name="120" href="#120">120</a>     <strong>private</strong> RandomAccessFile raFile;
<a name="121" href="#121">121</a> 
<a name="122" href="#122">122</a>     <em>/**<em>*</em></em>
<a name="123" href="#123">123</a> <em>     * Offset into prefix buffer at which content beings.</em>
<a name="124" href="#124">124</a> <em>     */</em>
<a name="125" href="#125">125</a>     <strong>private</strong> <strong>int</strong> contentOffset;
<a name="126" href="#126">126</a> 
<a name="127" href="#127">127</a>     <em>/**<em>*</em></em>
<a name="128" href="#128">128</a> <em>     * 8-bit encoding used reading single bytes from buffer and</em>
<a name="129" href="#129">129</a> <em>     * stream.</em>
<a name="130" href="#130">130</a> <em>     */</em>
<a name="131" href="#131">131</a>     <strong>private</strong> <strong>static</strong> <strong>final</strong> String DEFAULT_SINGLE_BYTE_ENCODING =
<a name="132" href="#132">132</a>         <span class="string">"ISO-8859-1"</span>;
<a name="133" href="#133">133</a> 
<a name="134" href="#134">134</a> 
<a name="135" href="#135">135</a>     <em>/**<em>*</em></em>
<a name="136" href="#136">136</a> <em>     * Constructor.</em>
<a name="137" href="#137">137</a> <em>     *</em>
<a name="138" href="#138">138</a> <em>     * @param buffer In-memory buffer of recordings prefix.  We read from</em>
<a name="139" href="#139">139</a> <em>     * here first and will only go to the backing file if &lt;code>size&lt;/code></em>
<a name="140" href="#140">140</a> <em>     * requested is greater than &lt;code>buffer.length&lt;/code>.</em>
<a name="141" href="#141">141</a> <em>     * @param size Total size of stream to replay in bytes.  Used to find</em>
<a name="142" href="#142">142</a> <em>     * EOS. This is total length of content including HTTP headers if</em>
<a name="143" href="#143">143</a> <em>     * present.</em>
<a name="144" href="#144">144</a> <em>     * @param responseBodyStart Where the response body starts in bytes.</em>
<a name="145" href="#145">145</a> <em>     * Used to skip over the HTTP headers if present.</em>
<a name="146" href="#146">146</a> <em>     * @param backingFilename Path to backing file with content in excess of</em>
<a name="147" href="#147">147</a> <em>     * whats in &lt;code>buffer&lt;/code>.</em>
<a name="148" href="#148">148</a> <em>     *</em>
<a name="149" href="#149">149</a> <em>     * @throws IOException</em>
<a name="150" href="#150">150</a> <em>     */</em>
<a name="151" href="#151">151</a>     <strong>public</strong> <a href="../../../org/archive/io/ByteReplayCharSequence.html">ByteReplayCharSequence</a>(byte[] buffer, <strong>long</strong> size,
<a name="152" href="#152">152</a>             <strong>long</strong> responseBodyStart, String backingFilename)
<a name="153" href="#153">153</a>         throws IOException {
<a name="154" href="#154">154</a> 
<a name="155" href="#155">155</a>         <strong>this</strong>.length = (<strong>int</strong>)(size - responseBodyStart);
<a name="156" href="#156">156</a>         <strong>this</strong>.absoluteLength = (<strong>int</strong>)size;
<a name="157" href="#157">157</a>         <strong>this</strong>.prefixBuffer = buffer;
<a name="158" href="#158">158</a>         <strong>this</strong>.contentOffset = (<strong>int</strong>)responseBodyStart;
<a name="159" href="#159">159</a> 
<a name="160" href="#160">160</a>         <em class="comment">// If amount to read is > than what is in our prefix buffer, then</em>
<a name="161" href="#161">161</a>         <em class="comment">// open the backing file.</em>
<a name="162" href="#162">162</a>         <strong>if</strong> (size > buffer.length) {
<a name="163" href="#163">163</a>             <strong>this</strong>.backingFilename = backingFilename;
<a name="164" href="#164">164</a>             <strong>this</strong>.raFile = <strong>new</strong> RandomAccessFile(backingFilename, <span class="string">"r"</span>);
<a name="165" href="#165">165</a>             <strong>this</strong>.wraparoundBuffer = <strong>new</strong> byte[<strong>this</strong>.prefixBuffer.length];
<a name="166" href="#166">166</a>             <strong>this</strong>.wrapOrigin = <strong>this</strong>.prefixBuffer.length;
<a name="167" href="#167">167</a>             <strong>this</strong>.wrapOffset = 0;
<a name="168" href="#168">168</a>             loadBuffer();
<a name="169" href="#169">169</a>         }
<a name="170" href="#170">170</a>     }
<a name="171" href="#171">171</a> 
<a name="172" href="#172">172</a>     <em>/**<em>*</em></em>
<a name="173" href="#173">173</a> <em>     * @return Length of characters in stream to replay.  Starts counting</em>
<a name="174" href="#174">174</a> <em>     * at the HTTP header/body boundary.</em>
<a name="175" href="#175">175</a> <em>     */</em>
<a name="176" href="#176">176</a>     <strong>public</strong> <strong>int</strong> length() {
<a name="177" href="#177">177</a>         <strong>return</strong> <strong>this</strong>.length;
<a name="178" href="#178">178</a>     }
<a name="179" href="#179">179</a> 
<a name="180" href="#180">180</a>     <em>/**<em>*</em></em>
<a name="181" href="#181">181</a> <em>     * Get character at passed absolute position.</em>
<a name="182" href="#182">182</a> <em>     *</em>
<a name="183" href="#183">183</a> <em>     * Called by {@link #charAt(int)} which has a relative index into the</em>
<a name="184" href="#184">184</a> <em>     * content, one that doesn't account for HTTP header if present.</em>
<a name="185" href="#185">185</a> <em>     *</em>
<a name="186" href="#186">186</a> <em>     * @param index Index into content adjusted to accomodate initial offset</em>
<a name="187" href="#187">187</a> <em>     * to get us past the HTTP header if present (i.e.</em>
<a name="188" href="#188">188</a> <em>     * {@link #contentOffset}).</em>
<a name="189" href="#189">189</a> <em>     *</em>
<a name="190" href="#190">190</a> <em>     * @return Characater at offset &lt;code>index&lt;/code>.</em>
<a name="191" href="#191">191</a> <em>     */</em>
<a name="192" href="#192">192</a>     <strong>public</strong> <strong>char</strong> <strong>char</strong>At(<strong>int</strong> index) {
<a name="193" href="#193">193</a>         <strong>int</strong> c = -1;
<a name="194" href="#194">194</a>         <em class="comment">// Add to index start-of-content offset to get us over HTTP header</em>
<a name="195" href="#195">195</a>         <em class="comment">// if present.</em>
<a name="196" href="#196">196</a>         index += <strong>this</strong>.contentOffset;
<a name="197" href="#197">197</a>         <strong>if</strong> (index &lt; <strong>this</strong>.prefixBuffer.length) {
<a name="198" href="#198">198</a>             <em class="comment">// If index is into our prefix buffer.</em>
<a name="199" href="#199">199</a>             c = <strong>this</strong>.prefixBuffer[index];
<a name="200" href="#200">200</a>         } <strong>else</strong> <strong>if</strong> (index >= <strong>this</strong>.wrapOrigin &amp;&amp;
<a name="201" href="#201">201</a>             (index - <strong>this</strong>.wrapOrigin) &lt; <strong>this</strong>.wraparoundBuffer.length) {
<a name="202" href="#202">202</a>             <em class="comment">// If index is into our buffer window on underlying backing file.</em>
<a name="203" href="#203">203</a>             c = <strong>this</strong>.wraparoundBuffer[
<a name="204" href="#204">204</a>                     ((index - <strong>this</strong>.wrapOrigin) + <strong>this</strong>.wrapOffset) %
<a name="205" href="#205">205</a>                         <strong>this</strong>.wraparoundBuffer.length];
<a name="206" href="#206">206</a>         } <strong>else</strong> {
<a name="207" href="#207">207</a>             <em class="comment">// Index is outside of both prefix buffer and our buffer window</em>
<a name="208" href="#208">208</a>             <em class="comment">// onto the underlying backing file.  Fix the buffer window</em>
<a name="209" href="#209">209</a>             <em class="comment">// location.</em>
<a name="210" href="#210">210</a>             c = faultCharAt(index);
<a name="211" href="#211">211</a>         }
<a name="212" href="#212">212</a>         <em class="comment">// Stream is treated as single byte.  Make sure characters returned</em>
<a name="213" href="#213">213</a>         <em class="comment">// are not negative.</em>
<a name="214" href="#214">214</a>         <strong>return</strong> (<strong>char</strong>)(c &amp; 0xff);
<a name="215" href="#215">215</a>     }
<a name="216" href="#216">216</a> 
<a name="217" href="#217">217</a>     <em>/**<em>*</em></em>
<a name="218" href="#218">218</a> <em>     * Get a character that's outside the current buffers.</em>
<a name="219" href="#219">219</a> <em>     *</em>
<a name="220" href="#220">220</a> <em>     * will cause the wraparoundBuffer to be changed to</em>
<a name="221" href="#221">221</a> <em>     * cover a region including the index</em>
<a name="222" href="#222">222</a> <em>     *</em>
<a name="223" href="#223">223</a> <em>     * if index is higher than the highest index in the</em>
<a name="224" href="#224">224</a> <em>     * wraparound buffer, buffer is moved forward such</em>
<a name="225" href="#225">225</a> <em>     * that requested char is last item in buffer</em>
<a name="226" href="#226">226</a> <em>     *</em>
<a name="227" href="#227">227</a> <em>     * if index is lower than lowest index in the</em>
<a name="228" href="#228">228</a> <em>     * wraparound buffer, buffet is reset centered around</em>
<a name="229" href="#229">229</a> <em>     * index</em>
<a name="230" href="#230">230</a> <em>     *</em>
<a name="231" href="#231">231</a> <em>     * @param index Index of character to fetch.</em>
<a name="232" href="#232">232</a> <em>     * @return A character that's outside the current buffers</em>
<a name="233" href="#233">233</a> <em>     */</em>
<a name="234" href="#234">234</a>     <strong>private</strong> <strong>int</strong> faultCharAt(<strong>int</strong> index) {
<a name="235" href="#235">235</a>         <strong>if</strong>(Thread.interrupted()) {
<a name="236" href="#236">236</a>             <strong>throw</strong> <strong>new</strong> RuntimeException(<span class="string">"thread interrupted"</span>);
<a name="237" href="#237">237</a>         }
<a name="238" href="#238">238</a>         <strong>if</strong>(index >= <strong>this</strong>.wrapOrigin + <strong>this</strong>.wraparoundBuffer.length) {
<a name="239" href="#239">239</a>             <em class="comment">// Moving forward</em>
<a name="240" href="#240">240</a>             <strong>while</strong> (index >= <strong>this</strong>.wrapOrigin + <strong>this</strong>.wraparoundBuffer.length)
<a name="241" href="#241">241</a>             {
<a name="242" href="#242">242</a>                 <em class="comment">// TODO optimize this</em>
<a name="243" href="#243">243</a>                 advanceBuffer();