Modified: websites/production/commons/content/proper/commons-compress/apidocs/src-html/org/apache/commons/compress/compressors/lz4/BlockLZ4CompressorOutputStream.html ============================================================================== --- websites/production/commons/content/proper/commons-compress/apidocs/src-html/org/apache/commons/compress/compressors/lz4/BlockLZ4CompressorOutputStream.html (original) +++ websites/production/commons/content/proper/commons-compress/apidocs/src-html/org/apache/commons/compress/compressors/lz4/BlockLZ4CompressorOutputStream.html Sat Feb 4 16:19:37 2017 @@ -32,439 +32,442 @@ <span class="sourceLineNo">024</span>import java.util.Deque;<a name="line.24"></a> <span class="sourceLineNo">025</span>import java.util.Iterator;<a name="line.25"></a> <span class="sourceLineNo">026</span>import java.util.LinkedList;<a name="line.26"></a> -<span class="sourceLineNo">027</span>import java.util.List;<a name="line.27"></a> -<span class="sourceLineNo">028</span><a name="line.28"></a> -<span class="sourceLineNo">029</span>import org.apache.commons.compress.compressors.CompressorOutputStream;<a name="line.29"></a> -<span class="sourceLineNo">030</span>import org.apache.commons.compress.compressors.lz77support.LZ77Compressor;<a name="line.30"></a> -<span class="sourceLineNo">031</span>import org.apache.commons.compress.compressors.lz77support.Parameters;<a name="line.31"></a> -<span class="sourceLineNo">032</span>import org.apache.commons.compress.utils.ByteUtils;<a name="line.32"></a> -<span class="sourceLineNo">033</span><a name="line.33"></a> -<span class="sourceLineNo">034</span>/**<a name="line.34"></a> -<span class="sourceLineNo">035</span> * CompressorOutputStream for the LZ4 block format.<a name="line.35"></a> -<span class="sourceLineNo">036</span> *<a name="line.36"></a> -<span class="sourceLineNo">037</span> * @see <a href="http://lz4.github.io/lz4/lz4_Block_format.html">LZ4 Block Format Description</a><a name="line.37"></a> -<span class="sourceLineNo">038</span> * @since 1.14<a name="line.38"></a> -<span class="sourceLineNo">039</span> * @NotThreadSafe<a name="line.39"></a> -<span class="sourceLineNo">040</span> */<a name="line.40"></a> -<span class="sourceLineNo">041</span>public class BlockLZ4CompressorOutputStream extends CompressorOutputStream {<a name="line.41"></a> -<span class="sourceLineNo">042</span><a name="line.42"></a> -<span class="sourceLineNo">043</span> private static final int MIN_BACK_REFERENCE_LENGTH = 4;<a name="line.43"></a> -<span class="sourceLineNo">044</span> private static final int MIN_LENGTH_OF_LAST_LITERAL = 5;<a name="line.44"></a> -<span class="sourceLineNo">045</span> private static final int MIN_OFFSET_OF_LAST_BACK_REFERENCE = 12;<a name="line.45"></a> -<span class="sourceLineNo">046</span><a name="line.46"></a> -<span class="sourceLineNo">047</span> /*<a name="line.47"></a> -<span class="sourceLineNo">048</span><a name="line.48"></a> -<span class="sourceLineNo">049</span> The LZ4 block format has a few properties that make it less<a name="line.49"></a> -<span class="sourceLineNo">050</span> straight-forward than one would hope:<a name="line.50"></a> -<span class="sourceLineNo">051</span><a name="line.51"></a> -<span class="sourceLineNo">052</span> * literal blocks and back-references must come in pairs (except<a name="line.52"></a> -<span class="sourceLineNo">053</span> for the very last literal block), so consecutive literal<a name="line.53"></a> -<span class="sourceLineNo">054</span> blocks created by the compressor must be merged into a single<a name="line.54"></a> -<span class="sourceLineNo">055</span> block.<a name="line.55"></a> -<span class="sourceLineNo">056</span><a name="line.56"></a> -<span class="sourceLineNo">057</span> * the start of a literal/back-reference pair contains the length<a name="line.57"></a> -<span class="sourceLineNo">058</span> of the back-reference (at least some part of it) so we can't<a name="line.58"></a> -<span class="sourceLineNo">059</span> start writing the literal before we know how long the next<a name="line.59"></a> -<span class="sourceLineNo">060</span> back-reference is going to be.<a name="line.60"></a> -<span class="sourceLineNo">061</span><a name="line.61"></a> -<span class="sourceLineNo">062</span> * there are special rules for the final blocks<a name="line.62"></a> -<span class="sourceLineNo">063</span><a name="line.63"></a> -<span class="sourceLineNo">064</span> > There are specific parsing rules to respect in order to remain<a name="line.64"></a> -<span class="sourceLineNo">065</span> > compatible with assumptions made by the decoder :<a name="line.65"></a> -<span class="sourceLineNo">066</span> ><a name="line.66"></a> -<span class="sourceLineNo">067</span> > 1. The last 5 bytes are always literals<a name="line.67"></a> -<span class="sourceLineNo">068</span> ><a name="line.68"></a> -<span class="sourceLineNo">069</span> > 2. The last match must start at least 12 bytes before end of<a name="line.69"></a> -<span class="sourceLineNo">070</span> > block. Consequently, a block with less than 13 bytes cannot be<a name="line.70"></a> -<span class="sourceLineNo">071</span> > compressed.<a name="line.71"></a> -<span class="sourceLineNo">072</span><a name="line.72"></a> -<span class="sourceLineNo">073</span> which means any back-reference may need to get rewritten as a<a name="line.73"></a> -<span class="sourceLineNo">074</span> literal block unless we know the next block is at least of<a name="line.74"></a> -<span class="sourceLineNo">075</span> length 5 and the sum of this block's length and offset and the<a name="line.75"></a> -<span class="sourceLineNo">076</span> next block's length is at least twelve.<a name="line.76"></a> -<span class="sourceLineNo">077</span><a name="line.77"></a> -<span class="sourceLineNo">078</span> */<a name="line.78"></a> -<span class="sourceLineNo">079</span><a name="line.79"></a> -<span class="sourceLineNo">080</span> private final LZ77Compressor compressor;<a name="line.80"></a> -<span class="sourceLineNo">081</span> private final OutputStream os;<a name="line.81"></a> -<span class="sourceLineNo">082</span><a name="line.82"></a> -<span class="sourceLineNo">083</span> // used in one-arg write method<a name="line.83"></a> -<span class="sourceLineNo">084</span> private final byte[] oneByte = new byte[1];<a name="line.84"></a> -<span class="sourceLineNo">085</span><a name="line.85"></a> -<span class="sourceLineNo">086</span> private boolean finished = false;<a name="line.86"></a> -<span class="sourceLineNo">087</span><a name="line.87"></a> -<span class="sourceLineNo">088</span> private Deque<Pair> pairs = new LinkedList<>();<a name="line.88"></a> -<span class="sourceLineNo">089</span> // keeps track of the last window-size bytes (64k) in order to be<a name="line.89"></a> -<span class="sourceLineNo">090</span> // able to expand back-references when needed<a name="line.90"></a> -<span class="sourceLineNo">091</span> private Deque<byte[]> expandedBlocks = new LinkedList<>();<a name="line.91"></a> -<span class="sourceLineNo">092</span><a name="line.92"></a> -<span class="sourceLineNo">093</span> /**<a name="line.93"></a> -<span class="sourceLineNo">094</span> * Creates a new LZ4 output stream.<a name="line.94"></a> -<span class="sourceLineNo">095</span> *<a name="line.95"></a> -<span class="sourceLineNo">096</span> * @param os<a name="line.96"></a> -<span class="sourceLineNo">097</span> * An OutputStream to read compressed data from<a name="line.97"></a> -<span class="sourceLineNo">098</span> *<a name="line.98"></a> -<span class="sourceLineNo">099</span> * @throws IOException if reading fails<a name="line.99"></a> -<span class="sourceLineNo">100</span> */<a name="line.100"></a> -<span class="sourceLineNo">101</span> public BlockLZ4CompressorOutputStream(final OutputStream os) throws IOException {<a name="line.101"></a> -<span class="sourceLineNo">102</span> this.os = os;<a name="line.102"></a> -<span class="sourceLineNo">103</span> int maxLen = BlockLZ4CompressorInputStream.WINDOW_SIZE - 1;<a name="line.103"></a> -<span class="sourceLineNo">104</span> compressor = new LZ77Compressor(new Parameters(BlockLZ4CompressorInputStream.WINDOW_SIZE,<a name="line.104"></a> -<span class="sourceLineNo">105</span> MIN_BACK_REFERENCE_LENGTH, maxLen, maxLen, maxLen),<a name="line.105"></a> -<span class="sourceLineNo">106</span> new LZ77Compressor.Callback() {<a name="line.106"></a> -<span class="sourceLineNo">107</span> public void accept(LZ77Compressor.Block block) throws IOException {<a name="line.107"></a> -<span class="sourceLineNo">108</span> //System.err.println(block);<a name="line.108"></a> -<span class="sourceLineNo">109</span> if (block instanceof LZ77Compressor.LiteralBlock) {<a name="line.109"></a> -<span class="sourceLineNo">110</span> addLiteralBlock((LZ77Compressor.LiteralBlock) block);<a name="line.110"></a> -<span class="sourceLineNo">111</span> } else if (block instanceof LZ77Compressor.BackReference) {<a name="line.111"></a> -<span class="sourceLineNo">112</span> addBackReference((LZ77Compressor.BackReference) block);<a name="line.112"></a> -<span class="sourceLineNo">113</span> } else if (block instanceof LZ77Compressor.EOD) {<a name="line.113"></a> -<span class="sourceLineNo">114</span> writeFinalLiteralBlock();<a name="line.114"></a> -<span class="sourceLineNo">115</span> }<a name="line.115"></a> -<span class="sourceLineNo">116</span> }<a name="line.116"></a> -<span class="sourceLineNo">117</span> });<a name="line.117"></a> -<span class="sourceLineNo">118</span> }<a name="line.118"></a> -<span class="sourceLineNo">119</span><a name="line.119"></a> -<span class="sourceLineNo">120</span> @Override<a name="line.120"></a> -<span class="sourceLineNo">121</span> public void write(int b) throws IOException {<a name="line.121"></a> -<span class="sourceLineNo">122</span> oneByte[0] = (byte) (b & 0xff);<a name="line.122"></a> -<span class="sourceLineNo">123</span> write(oneByte);<a name="line.123"></a> -<span class="sourceLineNo">124</span> }<a name="line.124"></a> -<span class="sourceLineNo">125</span><a name="line.125"></a> -<span class="sourceLineNo">126</span> @Override<a name="line.126"></a> -<span class="sourceLineNo">127</span> public void write(byte[] data, int off, int len) throws IOException {<a name="line.127"></a> -<span class="sourceLineNo">128</span> compressor.compress(data, off, len);<a name="line.128"></a> -<span class="sourceLineNo">129</span> }<a name="line.129"></a> -<span class="sourceLineNo">130</span><a name="line.130"></a> -<span class="sourceLineNo">131</span> @Override<a name="line.131"></a> -<span class="sourceLineNo">132</span> public void close() throws IOException {<a name="line.132"></a> -<span class="sourceLineNo">133</span> finish();<a name="line.133"></a> -<span class="sourceLineNo">134</span> os.close();<a name="line.134"></a> -<span class="sourceLineNo">135</span> }<a name="line.135"></a> -<span class="sourceLineNo">136</span><a name="line.136"></a> -<span class="sourceLineNo">137</span> /**<a name="line.137"></a> -<span class="sourceLineNo">138</span> * Compresses all remaining data and writes it to the stream,<a name="line.138"></a> -<span class="sourceLineNo">139</span> * doesn't close the underlying stream.<a name="line.139"></a> -<span class="sourceLineNo">140</span> * @throws IOException if an error occurs<a name="line.140"></a> -<span class="sourceLineNo">141</span> */<a name="line.141"></a> -<span class="sourceLineNo">142</span> public void finish() throws IOException {<a name="line.142"></a> -<span class="sourceLineNo">143</span> if (!finished) {<a name="line.143"></a> -<span class="sourceLineNo">144</span> compressor.finish();<a name="line.144"></a> -<span class="sourceLineNo">145</span> finished = true;<a name="line.145"></a> -<span class="sourceLineNo">146</span> }<a name="line.146"></a> -<span class="sourceLineNo">147</span> }<a name="line.147"></a> -<span class="sourceLineNo">148</span><a name="line.148"></a> -<span class="sourceLineNo">149</span> private void addLiteralBlock(LZ77Compressor.LiteralBlock block) throws IOException {<a name="line.149"></a> -<span class="sourceLineNo">150</span> Pair last = writeBlocksAndReturnUnfinishedPair(block.getLength());<a name="line.150"></a> -<span class="sourceLineNo">151</span> recordLiteral(last.addLiteral(block));<a name="line.151"></a> -<span class="sourceLineNo">152</span> clearUnusedBlocksAndPairs();<a name="line.152"></a> -<span class="sourceLineNo">153</span> }<a name="line.153"></a> -<span class="sourceLineNo">154</span><a name="line.154"></a> -<span class="sourceLineNo">155</span> private void addBackReference(LZ77Compressor.BackReference block) throws IOException {<a name="line.155"></a> -<span class="sourceLineNo">156</span> Pair last = writeBlocksAndReturnUnfinishedPair(block.getLength());<a name="line.156"></a> -<span class="sourceLineNo">157</span> last.setBackReference(block);<a name="line.157"></a> -<span class="sourceLineNo">158</span> recordBackReference(block);<a name="line.158"></a> -<span class="sourceLineNo">159</span> clearUnusedBlocksAndPairs();<a name="line.159"></a> -<span class="sourceLineNo">160</span> }<a name="line.160"></a> -<span class="sourceLineNo">161</span><a name="line.161"></a> -<span class="sourceLineNo">162</span> private Pair writeBlocksAndReturnUnfinishedPair(int length) throws IOException {<a name="line.162"></a> -<span class="sourceLineNo">163</span> writeWritablePairs(length);<a name="line.163"></a> -<span class="sourceLineNo">164</span> Pair last = pairs.peekLast();<a name="line.164"></a> -<span class="sourceLineNo">165</span> if (last == null || last.hasBackReference()) {<a name="line.165"></a> -<span class="sourceLineNo">166</span> last = new Pair();<a name="line.166"></a> -<span class="sourceLineNo">167</span> pairs.addLast(last);<a name="line.167"></a> -<span class="sourceLineNo">168</span> }<a name="line.168"></a> -<span class="sourceLineNo">169</span> return last;<a name="line.169"></a> -<span class="sourceLineNo">170</span> }<a name="line.170"></a> -<span class="sourceLineNo">171</span><a name="line.171"></a> -<span class="sourceLineNo">172</span> private void recordLiteral(byte[] b) {<a name="line.172"></a> -<span class="sourceLineNo">173</span> expandedBlocks.addFirst(b);<a name="line.173"></a> -<span class="sourceLineNo">174</span> }<a name="line.174"></a> -<span class="sourceLineNo">175</span><a name="line.175"></a> -<span class="sourceLineNo">176</span> private void clearUnusedBlocksAndPairs() {<a name="line.176"></a> -<span class="sourceLineNo">177</span> clearUnusedBlocks();<a name="line.177"></a> -<span class="sourceLineNo">178</span> clearUnusedPairs();<a name="line.178"></a> -<span class="sourceLineNo">179</span> }<a name="line.179"></a> -<span class="sourceLineNo">180</span><a name="line.180"></a> -<span class="sourceLineNo">181</span> private void clearUnusedBlocks() {<a name="line.181"></a> -<span class="sourceLineNo">182</span> int blockLengths = 0;<a name="line.182"></a> -<span class="sourceLineNo">183</span> int blocksToKeep = 0;<a name="line.183"></a> -<span class="sourceLineNo">184</span> for (byte[] b : expandedBlocks) {<a name="line.184"></a> -<span class="sourceLineNo">185</span> blocksToKeep++;<a name="line.185"></a> -<span class="sourceLineNo">186</span> blockLengths += b.length;<a name="line.186"></a> -<span class="sourceLineNo">187</span> if (blockLengths >= BlockLZ4CompressorInputStream.WINDOW_SIZE) {<a name="line.187"></a> -<span class="sourceLineNo">188</span> break;<a name="line.188"></a> -<span class="sourceLineNo">189</span> }<a name="line.189"></a> -<span class="sourceLineNo">190</span> }<a name="line.190"></a> -<span class="sourceLineNo">191</span> final int size = expandedBlocks.size();<a name="line.191"></a> -<span class="sourceLineNo">192</span> for (int i = blocksToKeep; i < size; i++) {<a name="line.192"></a> -<span class="sourceLineNo">193</span> expandedBlocks.removeLast();<a name="line.193"></a> -<span class="sourceLineNo">194</span> }<a name="line.194"></a> -<span class="sourceLineNo">195</span> }<a name="line.195"></a> -<span class="sourceLineNo">196</span><a name="line.196"></a> -<span class="sourceLineNo">197</span> private void recordBackReference(LZ77Compressor.BackReference block) {<a name="line.197"></a> -<span class="sourceLineNo">198</span> expandedBlocks.addFirst(expand(block.getOffset(), block.getLength()));<a name="line.198"></a> -<span class="sourceLineNo">199</span> }<a name="line.199"></a> -<span class="sourceLineNo">200</span><a name="line.200"></a> -<span class="sourceLineNo">201</span> private byte[] expand(final int offset, final int length) {<a name="line.201"></a> -<span class="sourceLineNo">202</span> byte[] expanded = new byte[length];<a name="line.202"></a> -<span class="sourceLineNo">203</span> if (offset == 1) { // surprisingly common special case<a name="line.203"></a> -<span class="sourceLineNo">204</span> byte[] block = expandedBlocks.peekFirst();<a name="line.204"></a> -<span class="sourceLineNo">205</span> byte b = block[block.length - 1];<a name="line.205"></a> -<span class="sourceLineNo">206</span> if (b != 0) { // the fresh array contains 0s anyway<a name="line.206"></a> -<span class="sourceLineNo">207</span> Arrays.fill(expanded, b);<a name="line.207"></a> -<span class="sourceLineNo">208</span> }<a name="line.208"></a> -<span class="sourceLineNo">209</span> } else {<a name="line.209"></a> -<span class="sourceLineNo">210</span> expandFromList(expanded, offset, length);<a name="line.210"></a> -<span class="sourceLineNo">211</span> }<a name="line.211"></a> -<span class="sourceLineNo">212</span> return expanded;<a name="line.212"></a> -<span class="sourceLineNo">213</span> }<a name="line.213"></a> -<span class="sourceLineNo">214</span><a name="line.214"></a> -<span class="sourceLineNo">215</span> private void expandFromList(final byte[] expanded, int offset, int length) {<a name="line.215"></a> -<span class="sourceLineNo">216</span> int offsetRemaining = offset;<a name="line.216"></a> -<span class="sourceLineNo">217</span> int lengthRemaining = length;<a name="line.217"></a> -<span class="sourceLineNo">218</span> int writeOffset = 0;<a name="line.218"></a> -<span class="sourceLineNo">219</span> while (lengthRemaining > 0) {<a name="line.219"></a> -<span class="sourceLineNo">220</span> // find block that contains offsetRemaining<a name="line.220"></a> -<span class="sourceLineNo">221</span> byte[] block = null;<a name="line.221"></a> -<span class="sourceLineNo">222</span> int copyLen, copyOffset;<a name="line.222"></a> -<span class="sourceLineNo">223</span> if (offsetRemaining > 0) {<a name="line.223"></a> -<span class="sourceLineNo">224</span> int blockOffset = 0;<a name="line.224"></a> -<span class="sourceLineNo">225</span> for (byte[] b : expandedBlocks) {<a name="line.225"></a> -<span class="sourceLineNo">226</span> if (b.length + blockOffset >= offsetRemaining) {<a name="line.226"></a> -<span class="sourceLineNo">227</span> block = b;<a name="line.227"></a> -<span class="sourceLineNo">228</span> break;<a name="line.228"></a> -<span class="sourceLineNo">229</span> }<a name="line.229"></a> -<span class="sourceLineNo">230</span> blockOffset += b.length;<a name="line.230"></a> -<span class="sourceLineNo">231</span> }<a name="line.231"></a> -<span class="sourceLineNo">232</span> copyOffset = blockOffset + block.length - offsetRemaining;<a name="line.232"></a> -<span class="sourceLineNo">233</span> copyLen = Math.min(lengthRemaining, block.length - copyOffset);<a name="line.233"></a> -<span class="sourceLineNo">234</span> } else {<a name="line.234"></a> -<span class="sourceLineNo">235</span> // offsetRemaining is negative and points into the expanded bytes<a name="line.235"></a> -<span class="sourceLineNo">236</span> block = expanded;<a name="line.236"></a> -<span class="sourceLineNo">237</span> copyOffset = writeOffset + offsetRemaining;<a name="line.237"></a> -<span class="sourceLineNo">238</span> copyLen = Math.min(lengthRemaining, writeOffset + offsetRemaining);<a name="line.238"></a> -<span class="sourceLineNo">239</span> }<a name="line.239"></a> -<span class="sourceLineNo">240</span> System.arraycopy(block, copyOffset, expanded, writeOffset, copyLen);<a name="line.240"></a> -<span class="sourceLineNo">241</span> offsetRemaining -= copyLen;<a name="line.241"></a> -<span class="sourceLineNo">242</span> lengthRemaining -= copyLen;<a name="line.242"></a> -<span class="sourceLineNo">243</span> writeOffset += copyLen;<a name="line.243"></a> -<span class="sourceLineNo">244</span> }<a name="line.244"></a> -<span class="sourceLineNo">245</span> }<a name="line.245"></a> -<span class="sourceLineNo">246</span><a name="line.246"></a> -<span class="sourceLineNo">247</span> private void clearUnusedPairs() {<a name="line.247"></a> -<span 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(int i = pairsToKeep; i < size; i++) {<a name="line.259"></a> -<span class="sourceLineNo">260</span> Pair p = pairs.peekFirst();<a name="line.260"></a> -<span class="sourceLineNo">261</span> if (p.hasBeenWritten()) {<a name="line.261"></a> -<span class="sourceLineNo">262</span> pairs.removeFirst();<a name="line.262"></a> -<span class="sourceLineNo">263</span> } else {<a name="line.263"></a> -<span class="sourceLineNo">264</span> break;<a name="line.264"></a> -<span class="sourceLineNo">265</span> }<a name="line.265"></a> -<span class="sourceLineNo">266</span> }<a name="line.266"></a> -<span class="sourceLineNo">267</span> }<a name="line.267"></a> -<span class="sourceLineNo">268</span><a name="line.268"></a> -<span class="sourceLineNo">269</span> private void writeFinalLiteralBlock() throws IOException {<a name="line.269"></a> -<span class="sourceLineNo">270</span> rewriteLastPairs();<a name="line.270"></a> -<span class="sourceLineNo">271</span> for (Pair p : pairs) {<a name="line.271"></a> -<span class="sourceLineNo">272</span> if (!p.hasBeenWritten()) {<a name="line.272"></a> -<span class="sourceLineNo">273</span> p.writeTo(os);<a name="line.273"></a> -<span class="sourceLineNo">274</span> }<a name="line.274"></a> -<span class="sourceLineNo">275</span> }<a name="line.275"></a> -<span class="sourceLineNo">276</span> pairs.clear();<a name="line.276"></a> -<span class="sourceLineNo">277</span> }<a name="line.277"></a> -<span class="sourceLineNo">278</span><a name="line.278"></a> -<span class="sourceLineNo">279</span> private void writeWritablePairs(int lengthOfBlocksAfterLastPair) throws IOException {<a name="line.279"></a> -<span class="sourceLineNo">280</span> int unwrittenLength = lengthOfBlocksAfterLastPair;<a name="line.280"></a> -<span class="sourceLineNo">281</span> for (Iterator<Pair> it = pairs.descendingIterator(); it.hasNext(); ) {<a name="line.281"></a> -<span class="sourceLineNo">282</span> Pair p = it.next();<a name="line.282"></a> -<span class="sourceLineNo">283</span> if (p.hasBeenWritten()) {<a name="line.283"></a> -<span class="sourceLineNo">284</span> break;<a name="line.284"></a> -<span class="sourceLineNo">285</span> }<a name="line.285"></a> -<span class="sourceLineNo">286</span> unwrittenLength += p.length();<a name="line.286"></a> -<span class="sourceLineNo">287</span> }<a name="line.287"></a> -<span class="sourceLineNo">288</span> for (Pair p : pairs) {<a name="line.288"></a> -<span class="sourceLineNo">289</span> if (p.hasBeenWritten()) {<a name="line.289"></a> -<span class="sourceLineNo">290</span> continue;<a name="line.290"></a> -<span class="sourceLineNo">291</span> }<a name="line.291"></a> -<span class="sourceLineNo">292</span> unwrittenLength -= p.length();<a name="line.292"></a> -<span class="sourceLineNo">293</span> if (p.canBeWritten(unwrittenLength)) {<a name="line.293"></a> -<span class="sourceLineNo">294</span> p.writeTo(os);<a name="line.294"></a> -<span class="sourceLineNo">295</span> } else {<a name="line.295"></a> -<span class="sourceLineNo">296</span> break;<a name="line.296"></a> -<span class="sourceLineNo">297</span> }<a name="line.297"></a> -<span class="sourceLineNo">298</span> }<a name="line.298"></a> -<span class="sourceLineNo">299</span> }<a name="line.299"></a> -<span class="sourceLineNo">300</span><a name="line.300"></a> -<span class="sourceLineNo">301</span> private void rewriteLastPairs() {<a name="line.301"></a> -<span class="sourceLineNo">302</span> LinkedList<Pair> lastPairs = new LinkedList<>();<a name="line.302"></a> -<span class="sourceLineNo">303</span> LinkedList<Integer> pairLength = new LinkedList<>();<a name="line.303"></a> -<span class="sourceLineNo">304</span> int offset = 0;<a name="line.304"></a> -<span class="sourceLineNo">305</span> for (Iterator<Pair> it = pairs.descendingIterator(); it.hasNext(); ) {<a name="line.305"></a> -<span class="sourceLineNo">306</span> Pair p = it.next();<a name="line.306"></a> -<span class="sourceLineNo">307</span> if (p.hasBeenWritten()) {<a name="line.307"></a> -<span class="sourceLineNo">308</span> break;<a name="line.308"></a> -<span class="sourceLineNo">309</span> }<a name="line.309"></a> -<span class="sourceLineNo">310</span> int len = p.length();<a name="line.310"></a> -<span class="sourceLineNo">311</span> pairLength.addFirst(len);<a name="line.311"></a> -<span class="sourceLineNo">312</span> lastPairs.addFirst(p);<a name="line.312"></a> -<span class="sourceLineNo">313</span> offset += len;<a name="line.313"></a> -<span class="sourceLineNo">314</span> if (offset >= MIN_OFFSET_OF_LAST_BACK_REFERENCE) {<a name="line.314"></a> -<span class="sourceLineNo">315</span> break;<a name="line.315"></a> -<span class="sourceLineNo">316</span> }<a name="line.316"></a> -<span class="sourceLineNo">317</span> }<a name="line.317"></a> -<span class="sourceLineNo">318</span> for (Pair p : lastPairs) {<a name="line.318"></a> -<span class="sourceLineNo">319</span> pairs.remove(p);<a name="line.319"></a> +<span class="sourceLineNo">027</span><a name="line.27"></a> +<span class="sourceLineNo">028</span>import org.apache.commons.compress.compressors.CompressorOutputStream;<a name="line.28"></a> +<span class="sourceLineNo">029</span>import org.apache.commons.compress.compressors.lz77support.LZ77Compressor;<a name="line.29"></a> +<span class="sourceLineNo">030</span>import org.apache.commons.compress.compressors.lz77support.Parameters;<a name="line.30"></a> +<span class="sourceLineNo">031</span>import org.apache.commons.compress.utils.ByteUtils;<a name="line.31"></a> +<span class="sourceLineNo">032</span><a name="line.32"></a> +<span class="sourceLineNo">033</span>/**<a name="line.33"></a> +<span class="sourceLineNo">034</span> * CompressorOutputStream for the LZ4 block format.<a name="line.34"></a> +<span class="sourceLineNo">035</span> *<a name="line.35"></a> +<span class="sourceLineNo">036</span> * @see <a href="http://lz4.github.io/lz4/lz4_Block_format.html">LZ4 Block Format Description</a><a name="line.36"></a> +<span class="sourceLineNo">037</span> * @since 1.14<a name="line.37"></a> +<span class="sourceLineNo">038</span> * @NotThreadSafe<a name="line.38"></a> +<span class="sourceLineNo">039</span> */<a name="line.39"></a> +<span class="sourceLineNo">040</span>public class BlockLZ4CompressorOutputStream extends CompressorOutputStream {<a name="line.40"></a> +<span class="sourceLineNo">041</span><a name="line.41"></a> +<span class="sourceLineNo">042</span> private static final int MIN_BACK_REFERENCE_LENGTH = 4;<a name="line.42"></a> +<span class="sourceLineNo">043</span> private static final int MIN_LENGTH_OF_LAST_LITERAL = 5;<a name="line.43"></a> +<span class="sourceLineNo">044</span> private static final int MIN_OFFSET_OF_LAST_BACK_REFERENCE = 12;<a name="line.44"></a> +<span class="sourceLineNo">045</span><a name="line.45"></a> +<span class="sourceLineNo">046</span> /*<a name="line.46"></a> +<span class="sourceLineNo">047</span><a name="line.47"></a> +<span class="sourceLineNo">048</span> The LZ4 block format has a few properties that make it less<a name="line.48"></a> +<span class="sourceLineNo">049</span> straight-forward than one would hope:<a name="line.49"></a> +<span class="sourceLineNo">050</span><a name="line.50"></a> +<span class="sourceLineNo">051</span> * literal blocks and back-references must come in pairs (except<a name="line.51"></a> +<span class="sourceLineNo">052</span> for the very last literal block), so consecutive literal<a name="line.52"></a> +<span class="sourceLineNo">053</span> blocks created by the compressor must be merged into a single<a name="line.53"></a> +<span class="sourceLineNo">054</span> block.<a name="line.54"></a> +<span class="sourceLineNo">055</span><a name="line.55"></a> +<span class="sourceLineNo">056</span> * the start of a literal/back-reference pair contains the length<a name="line.56"></a> +<span class="sourceLineNo">057</span> of the back-reference (at least some part of it) so we can't<a name="line.57"></a> +<span class="sourceLineNo">058</span> start writing the literal before we know how long the next<a name="line.58"></a> +<span class="sourceLineNo">059</span> back-reference is going to be.<a name="line.59"></a> +<span class="sourceLineNo">060</span><a name="line.60"></a> +<span class="sourceLineNo">061</span> * there are special rules for the final blocks<a name="line.61"></a> +<span class="sourceLineNo">062</span><a name="line.62"></a> +<span class="sourceLineNo">063</span> > There are specific parsing rules to respect in order to remain<a name="line.63"></a> +<span class="sourceLineNo">064</span> > compatible with assumptions made by the decoder :<a name="line.64"></a> +<span class="sourceLineNo">065</span> ><a name="line.65"></a> +<span class="sourceLineNo">066</span> > 1. The last 5 bytes are always literals<a name="line.66"></a> +<span class="sourceLineNo">067</span> ><a name="line.67"></a> +<span class="sourceLineNo">068</span> > 2. The last match must start at least 12 bytes before end of<a name="line.68"></a> +<span class="sourceLineNo">069</span> > block. Consequently, a block with less than 13 bytes cannot be<a name="line.69"></a> +<span class="sourceLineNo">070</span> > compressed.<a name="line.70"></a> +<span class="sourceLineNo">071</span><a name="line.71"></a> +<span class="sourceLineNo">072</span> which means any back-reference may need to get rewritten as a<a name="line.72"></a> +<span class="sourceLineNo">073</span> literal block unless we know the next block is at least of<a name="line.73"></a> +<span class="sourceLineNo">074</span> length 5 and the sum of this block's length and offset and the<a name="line.74"></a> +<span class="sourceLineNo">075</span> next block's length is at least twelve.<a name="line.75"></a> +<span class="sourceLineNo">076</span><a name="line.76"></a> +<span class="sourceLineNo">077</span> */<a name="line.77"></a> +<span class="sourceLineNo">078</span><a name="line.78"></a> +<span class="sourceLineNo">079</span> private final LZ77Compressor compressor;<a name="line.79"></a> +<span class="sourceLineNo">080</span> private final OutputStream os;<a name="line.80"></a> +<span class="sourceLineNo">081</span><a name="line.81"></a> +<span class="sourceLineNo">082</span> // used in one-arg write method<a name="line.82"></a> +<span class="sourceLineNo">083</span> private final byte[] oneByte = new byte[1];<a name="line.83"></a> +<span class="sourceLineNo">084</span><a name="line.84"></a> +<span class="sourceLineNo">085</span> private boolean finished = false;<a name="line.85"></a> +<span class="sourceLineNo">086</span><a name="line.86"></a> +<span class="sourceLineNo">087</span> private Deque<Pair> pairs = new LinkedList<>();<a name="line.87"></a> +<span class="sourceLineNo">088</span> // keeps track of the last window-size bytes (64k) in order to be<a name="line.88"></a> +<span class="sourceLineNo">089</span> // able to expand back-references when needed<a name="line.89"></a> +<span class="sourceLineNo">090</span> private Deque<byte[]> expandedBlocks = new LinkedList<>();<a name="line.90"></a> +<span class="sourceLineNo">091</span><a name="line.91"></a> +<span class="sourceLineNo">092</span> /**<a name="line.92"></a> +<span class="sourceLineNo">093</span> * Creates a new LZ4 output stream.<a name="line.93"></a> +<span class="sourceLineNo">094</span> *<a name="line.94"></a> +<span class="sourceLineNo">095</span> * @param os<a name="line.95"></a> +<span class="sourceLineNo">096</span> * An OutputStream to read compressed data from<a name="line.96"></a> +<span class="sourceLineNo">097</span> *<a name="line.97"></a> +<span class="sourceLineNo">098</span> * @throws IOException if reading fails<a name="line.98"></a> +<span class="sourceLineNo">099</span> */<a name="line.99"></a> +<span class="sourceLineNo">100</span> public BlockLZ4CompressorOutputStream(final OutputStream os) throws IOException {<a name="line.100"></a> +<span class="sourceLineNo">101</span> this.os = os;<a name="line.101"></a> +<span class="sourceLineNo">102</span> int maxLen = BlockLZ4CompressorInputStream.WINDOW_SIZE - 1;<a name="line.102"></a> +<span class="sourceLineNo">103</span> compressor = new LZ77Compressor(new Parameters(BlockLZ4CompressorInputStream.WINDOW_SIZE,<a name="line.103"></a> +<span class="sourceLineNo">104</span> MIN_BACK_REFERENCE_LENGTH, maxLen, maxLen, maxLen),<a name="line.104"></a> +<span class="sourceLineNo">105</span> new LZ77Compressor.Callback() {<a name="line.105"></a> +<span class="sourceLineNo">106</span> public void accept(LZ77Compressor.Block block) throws IOException {<a name="line.106"></a> +<span class="sourceLineNo">107</span> //System.err.println(block);<a name="line.107"></a> +<span class="sourceLineNo">108</span> if (block instanceof LZ77Compressor.LiteralBlock) {<a name="line.108"></a> +<span class="sourceLineNo">109</span> addLiteralBlock((LZ77Compressor.LiteralBlock) block);<a name="line.109"></a> +<span class="sourceLineNo">110</span> } else if (block instanceof LZ77Compressor.BackReference) {<a name="line.110"></a> +<span class="sourceLineNo">111</span> addBackReference((LZ77Compressor.BackReference) block);<a name="line.111"></a> +<span class="sourceLineNo">112</span> } else if (block instanceof LZ77Compressor.EOD) {<a name="line.112"></a> +<span class="sourceLineNo">113</span> writeFinalLiteralBlock();<a name="line.113"></a> +<span class="sourceLineNo">114</span> }<a name="line.114"></a> +<span class="sourceLineNo">115</span> }<a name="line.115"></a> +<span class="sourceLineNo">116</span> });<a name="line.116"></a> +<span class="sourceLineNo">117</span> }<a name="line.117"></a> +<span class="sourceLineNo">118</span><a name="line.118"></a> +<span class="sourceLineNo">119</span> @Override<a name="line.119"></a> +<span class="sourceLineNo">120</span> public void write(int b) throws IOException {<a name="line.120"></a> +<span class="sourceLineNo">121</span> oneByte[0] = (byte) (b & 0xff);<a name="line.121"></a> +<span class="sourceLineNo">122</span> write(oneByte);<a name="line.122"></a> +<span class="sourceLineNo">123</span> }<a name="line.123"></a> +<span class="sourceLineNo">124</span><a name="line.124"></a> +<span class="sourceLineNo">125</span> @Override<a name="line.125"></a> +<span class="sourceLineNo">126</span> public void write(byte[] data, int off, int len) throws IOException {<a name="line.126"></a> +<span class="sourceLineNo">127</span> compressor.compress(data, off, len);<a name="line.127"></a> +<span class="sourceLineNo">128</span> }<a name="line.128"></a> +<span class="sourceLineNo">129</span><a name="line.129"></a> +<span class="sourceLineNo">130</span> @Override<a name="line.130"></a> +<span class="sourceLineNo">131</span> public void close() throws IOException {<a name="line.131"></a> +<span class="sourceLineNo">132</span> finish();<a name="line.132"></a> +<span class="sourceLineNo">133</span> os.close();<a name="line.133"></a> +<span class="sourceLineNo">134</span> }<a name="line.134"></a> +<span class="sourceLineNo">135</span><a name="line.135"></a> +<span class="sourceLineNo">136</span> /**<a name="line.136"></a> +<span class="sourceLineNo">137</span> * Compresses all remaining data and writes it to the stream,<a name="line.137"></a> +<span class="sourceLineNo">138</span> * doesn't close the underlying stream.<a name="line.138"></a> +<span class="sourceLineNo">139</span> * @throws IOException if an error occurs<a name="line.139"></a> +<span class="sourceLineNo">140</span> */<a name="line.140"></a> +<span class="sourceLineNo">141</span> public void finish() throws IOException {<a name="line.141"></a> +<span class="sourceLineNo">142</span> if (!finished) {<a name="line.142"></a> +<span class="sourceLineNo">143</span> compressor.finish();<a name="line.143"></a> +<span class="sourceLineNo">144</span> finished = true;<a name="line.144"></a> +<span class="sourceLineNo">145</span> }<a name="line.145"></a> +<span class="sourceLineNo">146</span> }<a name="line.146"></a> +<span class="sourceLineNo">147</span><a name="line.147"></a> +<span class="sourceLineNo">148</span> private void addLiteralBlock(LZ77Compressor.LiteralBlock block) throws IOException {<a name="line.148"></a> +<span class="sourceLineNo">149</span> Pair last = writeBlocksAndReturnUnfinishedPair(block.getLength());<a name="line.149"></a> +<span class="sourceLineNo">150</span> recordLiteral(last.addLiteral(block));<a name="line.150"></a> +<span class="sourceLineNo">151</span> clearUnusedBlocksAndPairs();<a name="line.151"></a> +<span class="sourceLineNo">152</span> }<a name="line.152"></a> +<span class="sourceLineNo">153</span><a name="line.153"></a> +<span class="sourceLineNo">154</span> private void addBackReference(LZ77Compressor.BackReference block) throws IOException {<a name="line.154"></a> +<span class="sourceLineNo">155</span> Pair last = writeBlocksAndReturnUnfinishedPair(block.getLength());<a name="line.155"></a> +<span class="sourceLineNo">156</span> last.setBackReference(block);<a name="line.156"></a> +<span class="sourceLineNo">157</span> recordBackReference(block);<a name="line.157"></a> +<span class="sourceLineNo">158</span> clearUnusedBlocksAndPairs();<a name="line.158"></a> +<span class="sourceLineNo">159</span> }<a name="line.159"></a> +<span class="sourceLineNo">160</span><a name="line.160"></a> +<span class="sourceLineNo">161</span> private Pair writeBlocksAndReturnUnfinishedPair(int length) throws IOException {<a name="line.161"></a> +<span class="sourceLineNo">162</span> writeWritablePairs(length);<a name="line.162"></a> +<span class="sourceLineNo">163</span> Pair last = pairs.peekLast();<a name="line.163"></a> +<span class="sourceLineNo">164</span> if (last == null || last.hasBackReference()) {<a name="line.164"></a> +<span class="sourceLineNo">165</span> last = new Pair();<a name="line.165"></a> +<span class="sourceLineNo">166</span> pairs.addLast(last);<a name="line.166"></a> +<span class="sourceLineNo">167</span> }<a name="line.167"></a> +<span class="sourceLineNo">168</span> return last;<a name="line.168"></a> +<span class="sourceLineNo">169</span> }<a name="line.169"></a> +<span class="sourceLineNo">170</span><a name="line.170"></a> +<span class="sourceLineNo">171</span> private void recordLiteral(byte[] b) {<a name="line.171"></a> +<span class="sourceLineNo">172</span> expandedBlocks.addFirst(b);<a name="line.172"></a> +<span class="sourceLineNo">173</span> }<a name="line.173"></a> +<span class="sourceLineNo">174</span><a name="line.174"></a> +<span class="sourceLineNo">175</span> private void clearUnusedBlocksAndPairs() {<a name="line.175"></a> +<span class="sourceLineNo">176</span> clearUnusedBlocks();<a name="line.176"></a> +<span class="sourceLineNo">177</span> clearUnusedPairs();<a name="line.177"></a> +<span class="sourceLineNo">178</span> }<a name="line.178"></a> +<span class="sourceLineNo">179</span><a name="line.179"></a> +<span class="sourceLineNo">180</span> private void clearUnusedBlocks() {<a name="line.180"></a> +<span class="sourceLineNo">181</span> int blockLengths = 0;<a name="line.181"></a> +<span class="sourceLineNo">182</span> int blocksToKeep = 0;<a name="line.182"></a> +<span class="sourceLineNo">183</span> for (byte[] b : expandedBlocks) {<a name="line.183"></a> +<span class="sourceLineNo">184</span> blocksToKeep++;<a name="line.184"></a> +<span class="sourceLineNo">185</span> blockLengths += b.length;<a name="line.185"></a> +<span class="sourceLineNo">186</span> if (blockLengths >= BlockLZ4CompressorInputStream.WINDOW_SIZE) {<a name="line.186"></a> +<span class="sourceLineNo">187</span> break;<a name="line.187"></a> +<span class="sourceLineNo">188</span> }<a name="line.188"></a> +<span class="sourceLineNo">189</span> }<a name="line.189"></a> +<span class="sourceLineNo">190</span> final int size = expandedBlocks.size();<a name="line.190"></a> +<span class="sourceLineNo">191</span> for (int i = blocksToKeep; i < size; i++) {<a name="line.191"></a> +<span class="sourceLineNo">192</span> expandedBlocks.removeLast();<a name="line.192"></a> +<span class="sourceLineNo">193</span> }<a name="line.193"></a> +<span class="sourceLineNo">194</span> }<a name="line.194"></a> +<span class="sourceLineNo">195</span><a name="line.195"></a> +<span class="sourceLineNo">196</span> private void recordBackReference(LZ77Compressor.BackReference block) {<a name="line.196"></a> +<span class="sourceLineNo">197</span> expandedBlocks.addFirst(expand(block.getOffset(), block.getLength()));<a name="line.197"></a> +<span class="sourceLineNo">198</span> }<a name="line.198"></a> +<span class="sourceLineNo">199</span><a name="line.199"></a> +<span class="sourceLineNo">200</span> private byte[] expand(final int offset, final int length) {<a name="line.200"></a> +<span class="sourceLineNo">201</span> byte[] expanded = new byte[length];<a name="line.201"></a> +<span class="sourceLineNo">202</span> if (offset == 1) { // surprisingly common special case<a name="line.202"></a> +<span class="sourceLineNo">203</span> byte[] block = expandedBlocks.peekFirst();<a name="line.203"></a> +<span class="sourceLineNo">204</span> byte b = block[block.length - 1];<a name="line.204"></a> +<span class="sourceLineNo">205</span> if (b != 0) { // the fresh array contains 0s anyway<a name="line.205"></a> +<span class="sourceLineNo">206</span> Arrays.fill(expanded, b);<a name="line.206"></a> +<span class="sourceLineNo">207</span> }<a name="line.207"></a> +<span class="sourceLineNo">208</span> } else {<a name="line.208"></a> +<span class="sourceLineNo">209</span> expandFromList(expanded, offset, length);<a name="line.209"></a> +<span class="sourceLineNo">210</span> }<a name="line.210"></a> +<span class="sourceLineNo">211</span> return expanded;<a name="line.211"></a> +<span class="sourceLineNo">212</span> }<a name="line.212"></a> +<span class="sourceLineNo">213</span><a name="line.213"></a> +<span class="sourceLineNo">214</span> private void expandFromList(final byte[] expanded, int offset, int length) {<a name="line.214"></a> +<span class="sourceLineNo">215</span> int offsetRemaining = offset;<a name="line.215"></a> +<span class="sourceLineNo">216</span> int lengthRemaining = length;<a name="line.216"></a> +<span class="sourceLineNo">217</span> int writeOffset = 0;<a name="line.217"></a> +<span class="sourceLineNo">218</span> while (lengthRemaining > 0) {<a name="line.218"></a> +<span class="sourceLineNo">219</span> // find block that contains offsetRemaining<a name="line.219"></a> +<span class="sourceLineNo">220</span> byte[] block = null;<a name="line.220"></a> +<span class="sourceLineNo">221</span> int copyLen, copyOffset;<a name="line.221"></a> +<span class="sourceLineNo">222</span> if (offsetRemaining > 0) {<a name="line.222"></a> +<span class="sourceLineNo">223</span> int blockOffset = 0;<a name="line.223"></a> +<span class="sourceLineNo">224</span> for (byte[] b : expandedBlocks) {<a name="line.224"></a> +<span class="sourceLineNo">225</span> if (b.length + blockOffset >= offsetRemaining) {<a name="line.225"></a> +<span class="sourceLineNo">226</span> block = b;<a name="line.226"></a> +<span class="sourceLineNo">227</span> break;<a name="line.227"></a> +<span class="sourceLineNo">228</span> }<a name="line.228"></a> +<span class="sourceLineNo">229</span> blockOffset += b.length;<a name="line.229"></a> +<span class="sourceLineNo">230</span> }<a name="line.230"></a> +<span class="sourceLineNo">231</span> if (block == null) {<a name="line.231"></a> +<span class="sourceLineNo">232</span> // should not be possible<a name="line.232"></a> +<span class="sourceLineNo">233</span> throw new IllegalStateException("failed to find a block containing offset " + offset);<a name="line.233"></a> +<span class="sourceLineNo">234</span> }<a name="line.234"></a> +<span class="sourceLineNo">235</span> copyOffset = blockOffset + block.length - offsetRemaining;<a name="line.235"></a> +<span class="sourceLineNo">236</span> copyLen = Math.min(lengthRemaining, block.length - copyOffset);<a name="line.236"></a> +<span class="sourceLineNo">237</span> } else {<a name="line.237"></a> +<span class="sourceLineNo">238</span> // offsetRemaining is negative and points into the expanded bytes<a name="line.238"></a> +<span class="sourceLineNo">239</span> block = expanded;<a name="line.239"></a> +<span class="sourceLineNo">240</span> copyOffset = writeOffset + offsetRemaining;<a name="line.240"></a> +<span class="sourceLineNo">241</span> copyLen = Math.min(lengthRemaining, writeOffset + offsetRemaining);<a name="line.241"></a> +<span class="sourceLineNo">242</span> }<a name="line.242"></a> +<span class="sourceLineNo">243</span> System.arraycopy(block, copyOffset, expanded, writeOffset, copyLen);<a name="line.243"></a> +<span class="sourceLineNo">244</span> offsetRemaining -= copyLen;<a name="line.244"></a> +<span class="sourceLineNo">245</span> lengthRemaining -= copyLen;<a name="line.245"></a> +<span class="sourceLineNo">246</span> writeOffset += copyLen;<a name="line.246"></a> +<span class="sourceLineNo">247</span> }<a name="line.247"></a> +<span class="sourceLineNo">248</span> }<a name="line.248"></a> +<span class="sourceLineNo">249</span><a name="line.249"></a> +<span class="sourceLineNo">250</span> private void clearUnusedPairs() {<a name="line.250"></a> +<span class="sourceLineNo">251</span> int pairLengths = 0;<a name="line.251"></a> +<span class="sourceLineNo">252</span> int pairsToKeep = 0;<a name="line.252"></a> +<span class="sourceLineNo">253</span> for (Iterator<Pair> it = pairs.descendingIterator(); it.hasNext(); ) {<a name="line.253"></a> +<span class="sourceLineNo">254</span> Pair p = it.next();<a name="line.254"></a> +<span class="sourceLineNo">255</span> pairsToKeep++;<a name="line.255"></a> +<span class="sourceLineNo">256</span> pairLengths += p.length();<a name="line.256"></a> +<span class="sourceLineNo">257</span> if (pairLengths >= BlockLZ4CompressorInputStream.WINDOW_SIZE) {<a name="line.257"></a> +<span class="sourceLineNo">258</span> break;<a name="line.258"></a> +<span class="sourceLineNo">259</span> }<a name="line.259"></a> +<span class="sourceLineNo">260</span> }<a name="line.260"></a> +<span class="sourceLineNo">261</span> final int size = pairs.size();<a name="line.261"></a> +<span class="sourceLineNo">262</span> for (int i = pairsToKeep; i < size; i++) {<a name="line.262"></a> +<span class="sourceLineNo">263</span> Pair p = pairs.peekFirst();<a name="line.263"></a> +<span class="sourceLineNo">264</span> if (p.hasBeenWritten()) {<a name="line.264"></a> +<span class="sourceLineNo">265</span> pairs.removeFirst();<a name="line.265"></a> +<span class="sourceLineNo">266</span> } else {<a name="line.266"></a> +<span class="sourceLineNo">267</span> break;<a name="line.267"></a> +<span class="sourceLineNo">268</span> }<a name="line.268"></a> +<span class="sourceLineNo">269</span> }<a name="line.269"></a> +<span class="sourceLineNo">270</span> }<a name="line.270"></a> +<span class="sourceLineNo">271</span><a name="line.271"></a> +<span class="sourceLineNo">272</span> private void writeFinalLiteralBlock() throws IOException {<a name="line.272"></a> +<span class="sourceLineNo">273</span> rewriteLastPairs();<a name="line.273"></a> +<span class="sourceLineNo">274</span> for (Pair p : pairs) {<a name="line.274"></a> +<span class="sourceLineNo">275</span> if (!p.hasBeenWritten()) {<a name="line.275"></a> +<span class="sourceLineNo">276</span> p.writeTo(os);<a name="line.276"></a> +<span class="sourceLineNo">277</span> }<a name="line.277"></a> +<span class="sourceLineNo">278</span> }<a name="line.278"></a> +<span class="sourceLineNo">279</span> pairs.clear();<a name="line.279"></a> +<span class="sourceLineNo">280</span> }<a name="line.280"></a> +<span class="sourceLineNo">281</span><a name="line.281"></a> +<span class="sourceLineNo">282</span> private void writeWritablePairs(int lengthOfBlocksAfterLastPair) throws IOException {<a name="line.282"></a> +<span class="sourceLineNo">283</span> int unwrittenLength = lengthOfBlocksAfterLastPair;<a name="line.283"></a> +<span class="sourceLineNo">284</span> for (Iterator<Pair> it = pairs.descendingIterator(); it.hasNext(); ) {<a name="line.284"></a> +<span class="sourceLineNo">285</span> Pair p = it.next();<a name="line.285"></a> +<span class="sourceLineNo">286</span> if (p.hasBeenWritten()) {<a name="line.286"></a> +<span class="sourceLineNo">287</span> break;<a name="line.287"></a> +<span class="sourceLineNo">288</span> }<a name="line.288"></a> +<span class="sourceLineNo">289</span> unwrittenLength += p.length();<a name="line.289"></a> +<span class="sourceLineNo">290</span> }<a name="line.290"></a> +<span class="sourceLineNo">291</span> for (Pair p : pairs) {<a name="line.291"></a> +<span class="sourceLineNo">292</span> if (p.hasBeenWritten()) {<a name="line.292"></a> +<span class="sourceLineNo">293</span> continue;<a name="line.293"></a> +<span class="sourceLineNo">294</span> }<a name="line.294"></a> +<span class="sourceLineNo">295</span> unwrittenLength -= p.length();<a name="line.295"></a> +<span class="sourceLineNo">296</span> if (p.canBeWritten(unwrittenLength)) {<a name="line.296"></a> +<span class="sourceLineNo">297</span> p.writeTo(os);<a name="line.297"></a> +<span class="sourceLineNo">298</span> } else {<a name="line.298"></a> +<span class="sourceLineNo">299</span> break;<a name="line.299"></a> +<span class="sourceLineNo">300</span> }<a name="line.300"></a> +<span class="sourceLineNo">301</span> }<a name="line.301"></a> +<span class="sourceLineNo">302</span> }<a name="line.302"></a> +<span class="sourceLineNo">303</span><a name="line.303"></a> +<span class="sourceLineNo">304</span> private void rewriteLastPairs() {<a name="line.304"></a> +<span class="sourceLineNo">305</span> LinkedList<Pair> lastPairs = new LinkedList<>();<a name="line.305"></a> +<span class="sourceLineNo">306</span> LinkedList<Integer> pairLength = new LinkedList<>();<a name="line.306"></a> +<span class="sourceLineNo">307</span> int offset = 0;<a name="line.307"></a> +<span class="sourceLineNo">308</span> for (Iterator<Pair> it = pairs.descendingIterator(); it.hasNext(); ) {<a name="line.308"></a> +<span class="sourceLineNo">309</span> Pair p = it.next();<a name="line.309"></a> +<span class="sourceLineNo">310</span> if (p.hasBeenWritten()) {<a name="line.310"></a> +<span class="sourceLineNo">311</span> break;<a name="line.311"></a> +<span class="sourceLineNo">312</span> }<a name="line.312"></a> +<span class="sourceLineNo">313</span> int len = p.length();<a name="line.313"></a> +<span class="sourceLineNo">314</span> pairLength.addFirst(len);<a name="line.314"></a> +<span class="sourceLineNo">315</span> lastPairs.addFirst(p);<a name="line.315"></a> +<span class="sourceLineNo">316</span> offset += len;<a name="line.316"></a> +<span class="sourceLineNo">317</span> if (offset >= MIN_OFFSET_OF_LAST_BACK_REFERENCE) {<a name="line.317"></a> +<span class="sourceLineNo">318</span> break;<a name="line.318"></a> +<span class="sourceLineNo">319</span> }<a name="line.319"></a> <span class="sourceLineNo">320</span> }<a name="line.320"></a> -<span class="sourceLineNo">321</span> // lastPairs may contain between one and four Pairs:<a name="line.321"></a> -<span class="sourceLineNo">322</span> // * the last pair may be a one byte literal<a name="line.322"></a> -<span class="sourceLineNo">323</span> // * all other Pairs contain a back-reference which must be four bytes long at minimum<a name="line.323"></a> -<span class="sourceLineNo">324</span> // we could merge them all into a single literal block but<a name="line.324"></a> -<span class="sourceLineNo">325</span> // this may harm compression. For example compressing<a name="line.325"></a> -<span class="sourceLineNo">326</span> // "bla.tar" from our tests yields a last block containing a<a name="line.326"></a> -<span class="sourceLineNo">327</span> // back-reference of length > 2k and we'd end up with a last<a name="line.327"></a> -<span class="sourceLineNo">328</span> // literal of that size rather than a 2k back-reference and a<a name="line.328"></a> -<span class="sourceLineNo">329</span> // 12 byte literal at the end.<a name="line.329"></a> -<span class="sourceLineNo">330</span><a name="line.330"></a> -<span class="sourceLineNo">331</span> // Instead we merge all but the first of lastPairs into a new<a name="line.331"></a> -<span class="sourceLineNo">332</span> // literal-only Pair "replacement" and look at the<a name="line.332"></a> -<span class="sourceLineNo">333</span> // back-reference in the first of lastPairs and see if we can<a name="line.333"></a> -<span class="sourceLineNo">334</span> // split it. We can split it if it is longer than 16 -<a name="line.334"></a> -<span class="sourceLineNo">335</span> // replacement.length (i.e. the minimal length of four is kept<a name="line.335"></a> -<span class="sourceLineNo">336</span> // while making sure the last literal is at least twelve bytes<a name="line.336"></a> -<span class="sourceLineNo">337</span> // long). If we can't split it, we expand the first of the pairs<a name="line.337"></a> -<span class="sourceLineNo">338</span> // as well.<a name="line.338"></a> -<span class="sourceLineNo">339</span><a name="line.339"></a> -<span class="sourceLineNo">340</span> // this is not optimal, we could get better compression<a name="line.340"></a> -<span class="sourceLineNo">341</span> // results with more complex approaches as the last literal<a name="line.341"></a> -<span class="sourceLineNo">342</span> // only needs to be five bytes long if the previous<a name="line.342"></a> -<span class="sourceLineNo">343</span> // back-reference has an offset big enough<a name="line.343"></a> -<span class="sourceLineNo">344</span><a name="line.344"></a> -<span class="sourceLineNo">345</span> final int lastPairsSize = lastPairs.size();<a name="line.345"></a> -<span class="sourceLineNo">346</span> int toExpand = 0;<a name="line.346"></a> -<span class="sourceLineNo">347</span> for (int i = 1; i < lastPairsSize; i++) {<a name="line.347"></a> -<span class="sourceLineNo">348</span> toExpand += pairLength.get(i);<a name="line.348"></a> -<span class="sourceLineNo">349</span> }<a name="line.349"></a> -<span class="sourceLineNo">350</span> Pair replacement = new Pair();<a name="line.350"></a> -<span class="sourceLineNo">351</span> if (toExpand > 0) {<a name="line.351"></a> -<span class="sourceLineNo">352</span> replacement.prependLiteral(expand(toExpand, toExpand));<a name="line.352"></a> -<span class="sourceLineNo">353</span> }<a name="line.353"></a> -<span class="sourceLineNo">354</span> Pair splitCandidate = lastPairs.get(0);<a name="line.354"></a> -<span class="sourceLineNo">355</span> int stillNeeded = MIN_OFFSET_OF_LAST_BACK_REFERENCE - toExpand;<a name="line.355"></a> -<span class="sourceLineNo">356</span> if (splitCandidate.hasBackReference()<a name="line.356"></a> -<span class="sourceLineNo">357</span> && splitCandidate.backReferenceLength() >= MIN_BACK_REFERENCE_LENGTH + stillNeeded) {<a name="line.357"></a> -<span class="sourceLineNo">358</span> replacement.prependLiteral(expand(toExpand + stillNeeded, stillNeeded));<a name="line.358"></a> -<span class="sourceLineNo">359</span> pairs.add(splitCandidate.splitWithNewBackReferenceLengthOf(splitCandidate.backReferenceLength()<a name="line.359"></a> -<span class="sourceLineNo">360</span> - stillNeeded));<a name="line.360"></a> -<span class="sourceLineNo">361</span> } else {<a name="line.361"></a> -<span class="sourceLineNo">362</span> if (splitCandidate.hasBackReference()) {<a name="line.362"></a> -<span class="sourceLineNo">363</span> int brLen = splitCandidate.backReferenceLength();<a name="line.363"></a> -<span class="sourceLineNo">364</span> replacement.prependLiteral(expand(toExpand + brLen, brLen));<a name="line.364"></a> -<span class="sourceLineNo">365</span> }<a name="line.365"></a> -<span class="sourceLineNo">366</span> splitCandidate.prependTo(replacement);<a name="line.366"></a> -<span class="sourceLineNo">367</span> }<a name="line.367"></a> -<span class="sourceLineNo">368</span> pairs.add(replacement);<a name="line.368"></a> -<span class="sourceLineNo">369</span> }<a name="line.369"></a> -<span class="sourceLineNo">370</span><a name="line.370"></a> -<span class="sourceLineNo">371</span> final static class Pair {<a name="line.371"></a> -<span class="sourceLineNo">372</span> private final Deque<byte[]> literals = new LinkedList<>();<a name="line.372"></a> -<span class="sourceLineNo">373</span> private int brOffset, brLength;<a name="line.373"></a> -<span class="sourceLineNo">374</span> private boolean written;<a name="line.374"></a> -<span class="sourceLineNo">375</span><a name="line.375"></a> -<span class="sourceLineNo">376</span> private void prependLiteral(byte[] data) {<a name="line.376"></a> -<span class="sourceLineNo">377</span> literals.addFirst(data);<a name="line.377"></a> -<span class="sourceLineNo">378</span> }<a name="line.378"></a> -<span class="sourceLineNo">379</span> byte[] addLiteral(LZ77Compressor.LiteralBlock block) {<a name="line.379"></a> -<span class="sourceLineNo">380</span> byte[] copy = Arrays.copyOfRange(block.getData(), block.getOffset(),<a name="line.380"></a> -<span class="sourceLineNo">381</span> block.getOffset() + block.getLength());<a name="line.381"></a> -<span class="sourceLineNo">382</span> literals.add(copy);<a name="line.382"></a> -<span class="sourceLineNo">383</span> return copy;<a name="line.383"></a> -<span class="sourceLineNo">384</span> }<a name="line.384"></a> -<span class="sourceLineNo">385</span> void setBackReference(LZ77Compressor.BackReference block) {<a name="line.385"></a> -<span class="sourceLineNo">386</span> if (hasBackReference()) {<a name="line.386"></a> -<span class="sourceLineNo">387</span> throw new IllegalStateException();<a name="line.387"></a> -<span class="sourceLineNo">388</span> }<a name="line.388"></a> -<span class="sourceLineNo">389</span> brOffset = block.getOffset();<a name="line.389"></a> -<span class="sourceLineNo">390</span> brLength = block.getLength();<a name="line.390"></a> -<span class="sourceLineNo">391</span> }<a name="line.391"></a> -<span class="sourceLineNo">392</span> boolean hasBackReference() {<a name="line.392"></a> -<span class="sourceLineNo">393</span> return brOffset > 0;<a name="line.393"></a> +<span class="sourceLineNo">321</span> for (Pair p : lastPairs) {<a name="line.321"></a> +<span class="sourceLineNo">322</span> pairs.remove(p);<a name="line.322"></a> +<span class="sourceLineNo">323</span> }<a name="line.323"></a> +<span class="sourceLineNo">324</span> // lastPairs may contain between one and four Pairs:<a name="line.324"></a> +<span class="sourceLineNo">325</span> // * the last pair may be a one byte literal<a name="line.325"></a> +<span class="sourceLineNo">326</span> // * all other Pairs contain a back-reference which must be four bytes long at minimum<a name="line.326"></a> +<span class="sourceLineNo">327</span> // we could merge them all into a single literal block but<a name="line.327"></a> +<span class="sourceLineNo">328</span> // this may harm compression. For example compressing<a name="line.328"></a> +<span class="sourceLineNo">329</span> // "bla.tar" from our tests yields a last block containing a<a name="line.329"></a> +<span class="sourceLineNo">330</span> // back-reference of length > 2k and we'd end up with a last<a name="line.330"></a> +<span class="sourceLineNo">331</span> // literal of that size rather than a 2k back-reference and a<a name="line.331"></a> +<span class="sourceLineNo">332</span> // 12 byte literal at the end.<a name="line.332"></a> +<span class="sourceLineNo">333</span><a name="line.333"></a> +<span class="sourceLineNo">334</span> // Instead we merge all but the first of lastPairs into a new<a name="line.334"></a> +<span class="sourceLineNo">335</span> // literal-only Pair "replacement" and look at the<a name="line.335"></a> +<span class="sourceLineNo">336</span> // back-reference in the first of lastPairs and see if we can<a name="line.336"></a> +<span class="sourceLineNo">337</span> // split it. We can split it if it is longer than 16 -<a name="line.337"></a> +<span class="sourceLineNo">338</span> // replacement.length (i.e. the minimal length of four is kept<a name="line.338"></a> +<span class="sourceLineNo">339</span> // while making sure the last literal is at least twelve bytes<a name="line.339"></a> +<span class="sourceLineNo">340</span> // long). If we can't split it, we expand the first of the pairs<a name="line.340"></a> +<span class="sourceLineNo">341</span> // as well.<a name="line.341"></a> +<span class="sourceLineNo">342</span><a name="line.342"></a> +<span class="sourceLineNo">343</span> // this is not optimal, we could get better compression<a name="line.343"></a> +<span class="sourceLineNo">344</span> // results with more complex approaches as the last literal<a name="line.344"></a> +<span class="sourceLineNo">345</span> // only needs to be five bytes long if the previous<a name="line.345"></a> +<span class="sourceLineNo">346</span> // back-reference has an offset big enough<a name="line.346"></a> +<span class="sourceLineNo">347</span><a name="line.347"></a> +<span class="sourceLineNo">348</span> final int lastPairsSize = lastPairs.size();<a name="line.348"></a> +<span class="sourceLineNo">349</span> int toExpand = 0;<a name="line.349"></a> +<span class="sourceLineNo">350</span> for (int i = 1; i < lastPairsSize; i++) {<a name="line.350"></a> +<span class="sourceLineNo">351</span> toExpand += pairLength.get(i);<a name="line.351"></a> +<span class="sourceLineNo">352</span> }<a name="line.352"></a> +<span class="sourceLineNo">353</span> Pair replacement = new Pair();<a name="line.353"></a> +<span class="sourceLineNo">354</span> if (toExpand > 0) {<a name="line.354"></a> +<span class="sourceLineNo">355</span> replacement.prependLiteral(expand(toExpand, toExpand));<a name="line.355"></a> +<span class="sourceLineNo">356</span> }<a name="line.356"></a> +<span class="sourceLineNo">357</span> Pair splitCandidate = lastPairs.get(0);<a name="line.357"></a> +<span class="sourceLineNo">358</span> int stillNeeded = MIN_OFFSET_OF_LAST_BACK_REFERENCE - toExpand;<a name="line.358"></a> +<span class="sourceLineNo">359</span> if (splitCandidate.hasBackReference()<a name="line.359"></a> +<span class="sourceLineNo">360</span> && splitCandidate.backReferenceLength() >= MIN_BACK_REFERENCE_LENGTH + stillNeeded) {<a name="line.360"></a> +<span class="sourceLineNo">361</span> replacement.prependLiteral(expand(toExpand + stillNeeded, stillNeeded));<a name="line.361"></a> +<span class="sourceLineNo">362</span> pairs.add(splitCandidate.splitWithNewBackReferenceLengthOf(splitCandidate.backReferenceLength()<a name="line.362"></a> +<span class="sourceLineNo">363</span> - stillNeeded));<a name="line.363"></a> +<span class="sourceLineNo">364</span> } else {<a name="line.364"></a> +<span class="sourceLineNo">365</span> if (splitCandidate.hasBackReference()) {<a name="line.365"></a> +<span class="sourceLineNo">366</span> int brLen = splitCandidate.backReferenceLength();<a name="line.366"></a> +<span class="sourceLineNo">367</span> replacement.prependLiteral(expand(toExpand + brLen, brLen));<a name="line.367"></a> +<span class="sourceLineNo">368</span> }<a name="line.368"></a> +<span class="sourceLineNo">369</span> splitCandidate.prependTo(replacement);<a name="line.369"></a> +<span class="sourceLineNo">370</span> }<a name="line.370"></a> +<span class="sourceLineNo">371</span> pairs.add(replacement);<a name="line.371"></a> +<span class="sourceLineNo">372</span> }<a name="line.372"></a> +<span class="sourceLineNo">373</span><a name="line.373"></a> +<span class="sourceLineNo">374</span> final static class Pair {<a name="line.374"></a> +<span class="sourceLineNo">375</span> private final Deque<byte[]> literals = new LinkedList<>();<a name="line.375"></a> +<span class="sourceLineNo">376</span> private int brOffset, brLength;<a name="line.376"></a> +<span class="sourceLineNo">377</span> private boolean written;<a name="line.377"></a> +<span class="sourceLineNo">378</span><a name="line.378"></a> +<span class="sourceLineNo">379</span> private void prependLiteral(byte[] data) {<a name="line.379"></a> +<span class="sourceLineNo">380</span> literals.addFirst(data);<a name="line.380"></a> +<span class="sourceLineNo">381</span> }<a name="line.381"></a> +<span class="sourceLineNo">382</span> byte[] addLiteral(LZ77Compressor.LiteralBlock block) {<a name="line.382"></a> +<span class="sourceLineNo">383</span> byte[] copy = Arrays.copyOfRange(block.getData(), block.getOffset(),<a name="line.383"></a> +<span class="sourceLineNo">384</span> block.getOffset() + block.getLength());<a name="line.384"></a> +<span class="sourceLineNo">385</span> literals.add(copy);<a name="line.385"></a> +<span class="sourceLineNo">386</span> return copy;<a name="line.386"></a> +<span class="sourceLineNo">387</span> }<a name="line.387"></a> +<span class="sourceLineNo">388</span> void setBackReference(LZ77Compressor.BackReference block) {<a name="line.388"></a> +<span class="sourceLineNo">389</span> if (hasBackReference()) {<a name="line.389"></a> +<span class="sourceLineNo">390</span> throw new IllegalStateException();<a name="line.390"></a> +<span class="sourceLineNo">391</span> }<a name="line.391"></a> +<span class="sourceLineNo">392</span> brOffset = block.getOffset();<a name="line.392"></a> +<span class="sourceLineNo">393</span> brLength = block.getLength();<a name="line.393"></a> <span class="sourceLineNo">394</span> }<a name="line.394"></a> -<span class="sourceLineNo">395</span> boolean canBeWritten(int lengthOfBlocksAfterThisPair) {<a name="line.395"></a> -<span class="sourceLineNo">396</span> return hasBackReference()<a name="line.396"></a> -<span class="sourceLineNo">397</span> && lengthOfBlocksAfterThisPair >= MIN_OFFSET_OF_LAST_BACK_REFERENCE + MIN_BACK_REFERENCE_LENGTH;<a name="line.397"></a> -<span class="sourceLineNo">398</span> }<a name="line.398"></a> -<span class="sourceLineNo">399</span> int length() {<a name="line.399"></a> -<span class="sourceLineNo">400</span> return literalLength() + brLength;<a name="line.400"></a> +<span class="sourceLineNo">395</span> boolean hasBackReference() {<a name="line.395"></a> +<span class="sourceLineNo">396</span> return brOffset > 0;<a name="line.396"></a> +<span class="sourceLineNo">397</span> }<a name="line.397"></a> +<span class="sourceLineNo">398</span> boolean canBeWritten(int lengthOfBlocksAfterThisPair) {<a name="line.398"></a> +<span class="sourceLineNo">399</span> return hasBackReference()<a name="line.399"></a> +<span class="sourceLineNo">400</span> && lengthOfBlocksAfterThisPair >= MIN_OFFSET_OF_LAST_BACK_REFERENCE + MIN_BACK_REFERENCE_LENGTH;<a name="line.400"></a> <span class="sourceLineNo">401</span> }<a name="line.401"></a> -<span class="sourceLineNo">402</span> private boolean hasBeenWritten() {<a name="line.402"></a> -<span class="sourceLineNo">403</span> return written;<a name="line.403"></a> +<span class="sourceLineNo">402</span> int length() {<a name="line.402"></a> +<span class="sourceLineNo">403</span> return literalLength() + brLength;<a name="line.403"></a> <span class="sourceLineNo">404</span> }<a name="line.404"></a> -<span class="sourceLineNo">405</span> void writeTo(OutputStream out) throws IOException {<a 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class="sourceLineNo">408</span> void writeTo(OutputStream out) throws IOException {<a name="line.408"></a> +<span class="sourceLineNo">409</span> int litLength = literalLength();<a name="line.409"></a> +<span class="sourceLineNo">410</span> out.write(lengths(litLength, brLength));<a name="line.410"></a> +<span class="sourceLineNo">411</span> if (litLength >= BlockLZ4CompressorInputStream.BACK_REFERENCE_SIZE_MASK) {<a name="line.411"></a> +<span class="sourceLineNo">412</span> writeLength(litLength - BlockLZ4CompressorInputStream.BACK_REFERENCE_SIZE_MASK, out);<a name="line.412"></a> <span class="sourceLineNo">413</span> }<a name="line.413"></a> -<span class="sourceLineNo">414</span> if (hasBackReference()) {<a name="line.414"></a> -<span class="sourceLineNo">415</span> ByteUtils.toLittleEndian(out, brOffset, 2);<a name="line.415"></a> -<span class="sourceLineNo">416</span> if (brLength - MIN_BACK_REFERENCE_LENGTH >= BlockLZ4CompressorInputStream.BACK_REFERENCE_SIZE_MASK) {<a name="line.416"></a> -<span class="sourceLineNo">417</span> writeLength(brLength - MIN_BACK_REFERENCE_LENGTH<a name="line.417"></a> -<span class="sourceLineNo">418</span> - BlockLZ4CompressorInputStream.BACK_REFERENCE_SIZE_MASK, out);<a name="line.418"></a> -<span class="sourceLineNo">419</span> }<a name="line.419"></a> -<span class="sourceLineNo">420</span> }<a name="line.420"></a> -<span class="sourceLineNo">421</span> written = true;<a name="line.421"></a> -<span class="sourceLineNo">422</span> }<a name="line.422"></a> -<span class="sourceLineNo">423</span> private int literalLength() {<a name="line.423"></a> -<span class="sourceLineNo">424</span> int length = 0;<a name="line.424"></a> -<span class="sourceLineNo">425</span> for (byte[] b : literals) {<a name="line.425"></a> -<span class="sourceLineNo">426</span> length += b.length;<a name="line.426"></a> -<span class="sourceLineNo">427</span> }<a name="line.427"></a> -<span class="sourceLineNo">428</span> return length;<a name="line.428"></a> -<span class="sourceLineNo">429</span> }<a name="line.429"></a> -<span class="sourceLineNo">430</span> private static int lengths(int litLength, int brLength) {<a name="line.430"></a> -<span class="sourceLineNo">431</span> int l = litLength < 15 ? litLength : 15;<a name="line.431"></a> -<span class="sourceLineNo">432</span> int br = brLength < 4 ? 0 : (brLength < 19 ? brLength - 4 : 15);<a name="line.432"></a> -<span class="sourceLineNo">433</span> return (l << BlockLZ4CompressorInputStream.SIZE_BITS) | br;<a name="line.433"></a> -<span class="sourceLineNo">434</span> }<a name="line.434"></a> -<span class="sourceLineNo">435</span> private static void writeLength(int length, OutputStream out) throws IOException {<a name="line.435"></a> -<span class="sourceLineNo">436</span> while (length >= 255) {<a name="line.436"></a> -<span class="sourceLineNo">437</span> out.write(255);<a name="line.437"></a> -<span class="sourceLineNo">438</span> length -= 255;<a name="line.438"></a> -<span class="sourceLineNo">439</span> }<a name="line.439"></a> -<span class="sourceLineNo">440</span> out.write(length);<a name="line.440"></a> -<span class="sourceLineNo">441</span> }<a name="line.441"></a> -<span class="sourceLineNo">442</span> private int backReferenceLength() {<a name="line.442"></a> -<span class="sourceLineNo">443</span> return brLength;<a name="line.443"></a> +<span class="sourceLineNo">414</span> for (byte[] b : literals) {<a name="line.414"></a> +<span class="sourceLineNo">415</span> out.write(b);<a name="line.415"></a> +<span class="sourceLineNo">416</span> }<a name="line.416"></a> +<span class="sourceLineNo">417</span> if (hasBackReference()) {<a name="line.417"></a> +<span class="sourceLineNo">418</span> ByteUtils.toLittleEndian(out, brOffset, 2);<a name="line.418"></a> +<span class="sourceLineNo">419</span> if (brLength - MIN_BACK_REFERENCE_LENGTH >= BlockLZ4CompressorInputStream.BACK_REFERENCE_SIZE_MASK) {<a name="line.419"></a> +<span class="sourceLineNo">420</span> writeLength(brLength - MIN_BACK_REFERENCE_LENGTH<a name="line.420"></a> +<span class="sourceLineNo">421</span> - BlockLZ4CompressorInputStream.BACK_REFERENCE_SIZE_MASK, out);<a name="line.421"></a> +<span class="sourceLineNo">422</span> }<a name="line.422"></a> +<span class="sourceLineNo">423</span> }<a name="line.423"></a> +<span class="sourceLineNo">424</span> written = true;<a name="line.424"></a> +<span class="sourceLineNo">425</span> }<a name="line.425"></a> +<span class="sourceLineNo">426</span> private int literalLength() {<a name="line.426"></a> +<span class="sourceLineNo">427</span> int length = 0;<a name="line.427"></a> +<span class="sourceLineNo">428</span> for (byte[] b : literals) {<a name="line.428"></a> +<span class="sourceLineNo">429</span> length += b.length;<a name="line.429"></a> +<span class="sourceLineNo">430</span> }<a name="line.430"></a> +<span class="sourceLineNo">431</span> return length;<a name="line.431"></a> +<span class="sourceLineNo">432</span> }<a name="line.432"></a> +<span class="sourceLineNo">433</span> private static int lengths(int litLength, int brLength) {<a name="line.433"></a> +<span class="sourceLineNo">434</span> int l = litLength < 15 ? litLength : 15;<a name="line.434"></a> +<span class="sourceLineNo">435</span> int br = brLength < 4 ? 0 : (brLength < 19 ? brLength - 4 : 15);<a name="line.435"></a> +<span class="sourceLineNo">436</span> return (l << BlockLZ4CompressorInputStream.SIZE_BITS) | br;<a name="line.436"></a> +<span class="sourceLineNo">437</span> }<a name="line.437"></a> +<span class="sourceLineNo">438</span> private static void writeLength(int length, OutputStream out) throws IOException {<a name="line.438"></a> +<span class="sourceLineNo">439</span> while (length >= 255) {<a name="line.439"></a> +<span class="sourceLineNo">440</span> out.write(255);<a name="line.440"></a> +<span class="sourceLineNo">441</span> length -= 255;<a name="line.441"></a> +<span class="sourceLineNo">442</span> }<a name="line.442"></a> +<span class="sourceLineNo">443</span> out.write(length);<a name="line.443"></a> <span class="sourceLineNo">444</span> }<a name="line.444"></a> -<span class="sourceLineNo">445</span> private void prependTo(Pair other) {<a name="line.445"></a> -<span class="sourceLineNo">446</span> Iterator<byte[]> litsBackwards = literals.descendingIterator();<a name="line.446"></a> -<span class="sourceLineNo">447</span> while (litsBackwards.hasNext()) {<a name="line.447"></a> -<span class="sourceLineNo">448</span> other.prependLiteral(litsBackwards.next());<a name="line.448"></a> -<span class="sourceLineNo">449</span> }<a name="line.449"></a> -<span class="sourceLineNo">450</span> }<a name="line.450"></a> -<span class="sourceLineNo">451</span> private Pair splitWithNewBackReferenceLengthOf(int newBackReferenceLength) {<a name="line.451"></a> -<span class="sourceLineNo">452</span> Pair p = new Pair();<a name="line.452"></a> -<span class="sourceLineNo">453</span> p.literals.addAll(literals);<a name="line.453"></a> -<span class="sourceLineNo">454</span> p.brOffset = brOffset;<a name="line.454"></a> -<span class="sourceLineNo">455</span> p.brLength = newBackReferenceLength;<a name="line.455"></a> -<span class="sourceLineNo">456</span> return p;<a name="line.456"></a> -<span class="sourceLineNo">457</span> }<a name="line.457"></a> -<span class="sourceLineNo">458</span> }<a name="line.458"></a> -<span class="sourceLineNo">459</span>}<a name="line.459"></a> +<span class="sourceLineNo">445</span> private int backReferenceLength() {<a name="line.445"></a> +<span class="sourceLineNo">446</span> return brLength;<a name="line.446"></a> +<span class="sourceLineNo">447</span> }<a name="line.447"></a> +<span class="sourceLineNo">448</span> private void prependTo(Pair other) {<a name="line.448"></a> +<span class="sourceLineNo">449</span> Iterator<byte[]> litsBackwards = literals.descendingIterator();<a name="line.449"></a> +<span class="sourceLineNo">450</span> while (litsBackwards.hasNext()) {<a name="line.450"></a> +<span class="sourceLineNo">451</span> other.prependLiteral(litsBackwards.next());<a name="line.451"></a> +<span class="sourceLineNo">452</span> }<a name="line.452"></a> +<span class="sourceLineNo">453</span> }<a name="line.453"></a> +<span class="sourceLineNo">454</span> private Pair splitWithNewBackReferenceLengthOf(int newBackReferenceLength) {<a name="line.454"></a> +<span class="sourceLineNo">455</span> Pair p = new Pair();<a name="line.455"></a> +<span class="sourceLineNo">456</span> p.literals.addAll(literals);<a name="line.456"></a> +<span class="sourceLineNo">457</span> p.brOffset = brOffset;<a name="line.457"></a> +<span class="sourceLineNo">458</span> p.brLength = newBackReferenceLength;<a name="line.458"></a> +<span class="sourceLineNo">459</span> return p;<a name="line.459"></a> +<span class="sourceLineNo">460</span> }<a name="line.460"></a> +<span class="sourceLineNo">461</span> }<a name="line.461"></a> +<span class="sourceLineNo">462</span>}<a name="line.462"></a>
