The Tor Browser / file comparison
comparison: mobile/android/base/background/bagheera/DeflateHelper.java
mobile/android/base/background/bagheera/DeflateHelper.java
- branch
- TOR_BUG_3246
- changeset 4
- fc2d59ddac77
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| -1:000000000000 | 0:109185c78dc0 |
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| 1 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 4 | |
| 5 package org.mozilla.gecko.background.bagheera; | |
| 6 | |
| 7 import java.io.UnsupportedEncodingException; | |
| 8 import java.util.zip.Deflater; | |
| 9 | |
| 10 import ch.boye.httpclientandroidlib.HttpEntity; | |
| 11 | |
| 12 public class DeflateHelper { | |
| 13 /** | |
| 14 * Conservative upper bound for zlib size, equivalent to the first few lines | |
| 15 * in zlib's deflateBound function. | |
| 16 * | |
| 17 * Includes zlib header. | |
| 18 * | |
| 19 * @param sourceLen | |
| 20 * the number of bytes to compress. | |
| 21 * @return the number of bytes to allocate for the compressed output. | |
| 22 */ | |
| 23 public static int deflateBound(final int sourceLen) { | |
| 24 return sourceLen + ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5 + 6; | |
| 25 } | |
| 26 | |
| 27 /** | |
| 28 * Deflate the input into the output array, returning the number of bytes | |
| 29 * written to output. | |
| 30 */ | |
| 31 public static int deflate(byte[] input, byte[] output) { | |
| 32 final Deflater deflater = new Deflater(); | |
| 33 deflater.setInput(input); | |
| 34 deflater.finish(); | |
| 35 | |
| 36 final int length = deflater.deflate(output); | |
| 37 deflater.end(); | |
| 38 return length; | |
| 39 } | |
| 40 | |
| 41 /** | |
| 42 * Deflate the input, returning an HttpEntity that offers an accurate window | |
| 43 * on the output. | |
| 44 * | |
| 45 * Note that this method does not trim the output array. (Test code can use | |
| 46 * TestDeflation#deflateTrimmed(byte[]).) | |
| 47 * | |
| 48 * Trimming would be more efficient for long-term space use, but we expect this | |
| 49 * entity to be transient. | |
| 50 * | |
| 51 * Note also that deflate can require <b>more</b> space than the input. | |
| 52 * {@link #deflateBound(int)} tells us the most it will use. | |
| 53 * | |
| 54 * @param bytes the input to deflate. | |
| 55 * @return the deflated input as an entity. | |
| 56 */ | |
| 57 public static HttpEntity deflateBytes(final byte[] bytes) { | |
| 58 // We would like to use DeflaterInputStream here, but it's minSDK=9, and we | |
| 59 // still target 8. It would also force us to use chunked Transfer-Encoding, | |
| 60 // so perhaps it's for the best! | |
| 61 | |
| 62 final byte[] out = new byte[deflateBound(bytes.length)]; | |
| 63 final int outLength = deflate(bytes, out); | |
| 64 return new BoundedByteArrayEntity(out, 0, outLength); | |
| 65 } | |
| 66 | |
| 67 public static HttpEntity deflateBody(final String payload) { | |
| 68 final byte[] bytes; | |
| 69 try { | |
| 70 bytes = payload.getBytes("UTF-8"); | |
| 71 } catch (UnsupportedEncodingException ex) { | |
| 72 // This will never happen. Thanks, Java! | |
| 73 throw new RuntimeException(ex); | |
| 74 } | |
| 75 return deflateBytes(bytes); | |
| 76 } | |
| 77 } |
