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Creation and playback of compressed SWFM files.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,162 @@ | ||
| /* | ||
| * Copyright 2015 Mozilla Foundation | ||
| * | ||
| * Licensed under the Apache License, Version 2.0 (the "License"); | ||
| * you may not use this file except in compliance with the License. | ||
| * You may obtain a copy of the License at | ||
| * | ||
| * http://www.apache.org/licenses/LICENSE-2.0 | ||
| * | ||
| * Unless required by applicable law or agreed to in writing, software | ||
| * distributed under the License is distributed on an "AS IS" BASIS, | ||
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| * See the License for the specific language governing permissions and | ||
| * limitations under the License. | ||
| */ | ||
|
|
||
| var fs = require('fs'); | ||
| var path = require('path'); | ||
| var temp = require('temp'); | ||
| var spawn = require('child_process').spawn; | ||
|
|
||
| // simple args parsing | ||
| var compressMethod = null; | ||
| var outputPath = null; | ||
| var inputPath = null; | ||
| for (var i = 2; i < process.argv.length;) { | ||
| var cmd = process.argv[i++]; | ||
| switch (cmd) { | ||
| case '--lzma': | ||
| case '-z': | ||
| compressMethod = 'lzma'; | ||
| break; | ||
| case '--zlib': | ||
| case '-c': | ||
| compressMethod = 'zlib'; | ||
| break; | ||
| case '--out': | ||
| case '-o': | ||
| outputPath = process.argv[i++]; | ||
| break; | ||
| default: | ||
| inputPath = cmd; // .swfm is expected | ||
| break; | ||
| } | ||
| } | ||
|
|
||
| function createRawSWFM(callback) { | ||
| // Create a temp file without 'MSWF' header. | ||
| fs.readFile(inputPath, function (err, data) { | ||
| if (err) return callback(err); | ||
| var header = data.slice(0, 4).toString(); | ||
| if (header !== 'MSWF') { | ||
| return callback(new Error('swfm file header is not found: found \"' + header + '\"')); | ||
| } | ||
| temp.open('swfm', function (err, info) { | ||
| if (err) return callback(err); | ||
| fs.write(info.fd, data, 4, data.length - 4, function (err) { | ||
| if (err) return callback(err); | ||
| fs.close(info.fd, function (err) { | ||
| if (err) return callback(err); | ||
| callback(null, info.path); | ||
| }); | ||
| }); | ||
| }); | ||
| }); | ||
| } | ||
|
|
||
| function compressViaGZip(rawDataPath, compressedDataPath, callback) { | ||
| // Running gzip. | ||
| var proc = spawn('gzip', ['-k9n', rawDataPath]); | ||
| var resultPath = rawDataPath + '.gz'; | ||
| proc.on('close', function (code) { | ||
| if (code !== 0 || !fs.existsSync(resultPath)) { | ||
| callback(new Error('Unable to run gzip')); | ||
| return; | ||
| } | ||
| // Prepending MSWC and zlib header before compressed data. | ||
| fs.writeFile(compressedDataPath, new Buffer("MSWC\u0078\u00DA", 'ascii'), function (err) { | ||
| if (err) return callback(err); | ||
| fs.readFile(resultPath, function (err, data) { | ||
| if (data[0] !== 0x1F || data[1] !== 0x8B || data[2] !== 0x08 || data[3] !== 0) { | ||
| return callback(new Error('Invalid gzip result')); | ||
| } | ||
| var dataStart = 10; | ||
| var dataEnd = data.length - 8; | ||
|
|
||
| // Appending adler32 at the end of data. | ||
| var a = 1, b = 0; | ||
| for (var i = dataStart; i < dataEnd; ++i) { | ||
| a = (a + (data[i] & 0xff)) % 65521; | ||
| b = (b + a) % 65521; | ||
| } | ||
| var adler32 = (b << 16) | a; | ||
| data[dataEnd] = (adler32 >> 24) & 255; | ||
| data[dataEnd + 1] = (adler32 >> 16) & 255; | ||
| data[dataEnd + 2] = (adler32 >> 8) & 255; | ||
| data[dataEnd + 3] = adler32 & 255; | ||
|
|
||
|
|
||
| if (err) return callback(err); | ||
| fs.appendFile(compressedDataPath, data.slice(dataStart, dataEnd + 4), function (err) { | ||
| fs.unlink(resultPath, callback); | ||
| }); | ||
| }); | ||
| }); | ||
| }); | ||
| } | ||
|
|
||
| function compressViaLzma(rawDataPath, compressedDataPath, callback) { | ||
| // Running lzma. | ||
| var proc = spawn('lzma', ['-zk9e', rawDataPath]); | ||
| var resultPath = rawDataPath + '.lzma'; | ||
| proc.on('close', function (code) { | ||
| if (code !== 0 || !fs.existsSync(resultPath)) { | ||
| callback(new Error('Unable to run lzma')); | ||
| return; | ||
| } | ||
| // Prepending MSWZ before lzma compressed data. | ||
| fs.writeFile(compressedDataPath, "MSWZ", function (err) { | ||
| if (err) return callback(err); | ||
| fs.readFile(resultPath, function (err, data) { | ||
| if (err) return callback(err); | ||
| fs.appendFile(compressedDataPath, data, function (err) { | ||
| fs.unlink(resultPath, callback); | ||
| }); | ||
| }); | ||
| }); | ||
| }); | ||
| } | ||
|
|
||
| function printUsage() { | ||
| console.info('Usage: node compressswfm.js [-c|-z] inputFile [-o outputFile]'); | ||
| } | ||
|
|
||
| if (!inputPath || !compressMethod) { | ||
| printUsage(); | ||
| process.exit(1); | ||
| } | ||
|
|
||
| if (!outputPath) { | ||
| var ext = path.extname(inputPath); | ||
| outputPath = inputPath.slice(0, -ext.length) + '.' + compressMethod + ext; | ||
| console.log('Compressed results at ' + outputPath); | ||
| } | ||
|
|
||
| createRawSWFM(function (err, path) { | ||
| if (err) throw err; | ||
| switch (compressMethod) { | ||
| case 'zlib': | ||
| compressViaGZip(path, outputPath, function (err) { | ||
| if (err) throw err; | ||
| console.log('Done. Compressed using ZLib.'); | ||
| }); | ||
| break; | ||
| case 'lzma': | ||
| compressViaLzma(path, outputPath, function (err) { | ||
| if (err) throw err; | ||
| console.log('Done. Compressed using LZMA.'); | ||
| }); | ||
| break; | ||
| } | ||
| }); |