1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/mobile/android/base/background/bagheera/DeflateHelper.java Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,77 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +package org.mozilla.gecko.background.bagheera;
1.9 +
1.10 +import java.io.UnsupportedEncodingException;
1.11 +import java.util.zip.Deflater;
1.12 +
1.13 +import ch.boye.httpclientandroidlib.HttpEntity;
1.14 +
1.15 +public class DeflateHelper {
1.16 + /**
1.17 + * Conservative upper bound for zlib size, equivalent to the first few lines
1.18 + * in zlib's deflateBound function.
1.19 + *
1.20 + * Includes zlib header.
1.21 + *
1.22 + * @param sourceLen
1.23 + * the number of bytes to compress.
1.24 + * @return the number of bytes to allocate for the compressed output.
1.25 + */
1.26 + public static int deflateBound(final int sourceLen) {
1.27 + return sourceLen + ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5 + 6;
1.28 + }
1.29 +
1.30 + /**
1.31 + * Deflate the input into the output array, returning the number of bytes
1.32 + * written to output.
1.33 + */
1.34 + public static int deflate(byte[] input, byte[] output) {
1.35 + final Deflater deflater = new Deflater();
1.36 + deflater.setInput(input);
1.37 + deflater.finish();
1.38 +
1.39 + final int length = deflater.deflate(output);
1.40 + deflater.end();
1.41 + return length;
1.42 + }
1.43 +
1.44 + /**
1.45 + * Deflate the input, returning an HttpEntity that offers an accurate window
1.46 + * on the output.
1.47 + *
1.48 + * Note that this method does not trim the output array. (Test code can use
1.49 + * TestDeflation#deflateTrimmed(byte[]).)
1.50 + *
1.51 + * Trimming would be more efficient for long-term space use, but we expect this
1.52 + * entity to be transient.
1.53 + *
1.54 + * Note also that deflate can require <b>more</b> space than the input.
1.55 + * {@link #deflateBound(int)} tells us the most it will use.
1.56 + *
1.57 + * @param bytes the input to deflate.
1.58 + * @return the deflated input as an entity.
1.59 + */
1.60 + public static HttpEntity deflateBytes(final byte[] bytes) {
1.61 + // We would like to use DeflaterInputStream here, but it's minSDK=9, and we
1.62 + // still target 8. It would also force us to use chunked Transfer-Encoding,
1.63 + // so perhaps it's for the best!
1.64 +
1.65 + final byte[] out = new byte[deflateBound(bytes.length)];
1.66 + final int outLength = deflate(bytes, out);
1.67 + return new BoundedByteArrayEntity(out, 0, outLength);
1.68 + }
1.69 +
1.70 + public static HttpEntity deflateBody(final String payload) {
1.71 + final byte[] bytes;
1.72 + try {
1.73 + bytes = payload.getBytes("UTF-8");
1.74 + } catch (UnsupportedEncodingException ex) {
1.75 + // This will never happen. Thanks, Java!
1.76 + throw new RuntimeException(ex);
1.77 + }
1.78 + return deflateBytes(bytes);
1.79 + }
1.80 +}
1.81 \ No newline at end of file
