git ssb

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var createHash = require('sha.js/sha256')
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var deepEqual = require('deep-equal')
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var jsbloom = require('jsbloom')
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exports.encode = function (value) {
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  if(null == value) return new Buffer(0)
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  var header = Buffer.concat([
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    data.seq, value.version,
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    value.items,
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    value.probability
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  ].map(function (e) {
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    var b = new Buffer(4)
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    b.writeUint32BE(0, e)
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    return b
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  }))
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  var lzBuffer = new Buffer(data.value.exportData(), 'base64')
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  return Buffer.concat([createHash().update(data).update(raw).digest(), data, lzBuffer])
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}
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exports.decode = function (buffer) {
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  if(buffer.length == 0)
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    throw new Error('empty buffer')
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  var hash = buffer.slice(0, 32)
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  if(!deepEqual(createHash().update(buffer.slice(32)).digest(), hash))
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    throw new Error('flumeview-bloom.decode: hash is incorrect')
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  var seq = buffer.readUInt32BE(32+0)
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  var version = buffer.readUInt32BE(32+4)
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  var items = buffer.readUInt32BE(32+8)
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  var probability = buffer.readUInt32BE(32+12)
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  var bloom = new jsbloom.filter(items, probability)
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  bloom.importData(data.splice(32+16).toString('base64')
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  return {
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    seq: seq, version: version,
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    items: items,
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    probability: probability,
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    value: bloom
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  }
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}
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