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Merge pull request #339 from junelife/compression
Support websocket compression
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,177 @@ | ||
| ////////////////////////////////////////////////////////////////////////////////////////////////// | ||
| // | ||
| // Compression.swift | ||
| // | ||
| // Created by Joseph Ross on 7/16/14. | ||
| // Copyright © 2017 Joseph Ross. | ||
| // | ||
| // 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. | ||
| // | ||
| ////////////////////////////////////////////////////////////////////////////////////////////////// | ||
|
|
||
| ////////////////////////////////////////////////////////////////////////////////////////////////// | ||
| // | ||
| // Compression implementation is implemented in conformance with RFC 7692 Compression Extensions | ||
| // for WebSocket: https://tools.ietf.org/html/rfc7692 | ||
| // | ||
| ////////////////////////////////////////////////////////////////////////////////////////////////// | ||
|
|
||
| import Foundation | ||
| import zlib | ||
|
|
||
| class Decompressor { | ||
| private var strm = z_stream() | ||
| private var buffer = [UInt8](repeating: 0, count: 0x2000) | ||
| private var inflateInitialized = false | ||
| private let windowBits:Int | ||
|
|
||
| init?(windowBits:Int) { | ||
| self.windowBits = windowBits | ||
| guard initInflate() else { return nil } | ||
| } | ||
|
|
||
| private func initInflate() -> Bool { | ||
| if Z_OK == inflateInit2_(&strm, -CInt(windowBits), | ||
| ZLIB_VERSION, CInt(MemoryLayout<z_stream>.size)) | ||
| { | ||
| inflateInitialized = true | ||
| return true | ||
| } | ||
| return false | ||
| } | ||
|
|
||
| func reset() throws { | ||
| teardownInflate() | ||
| guard initInflate() else { throw NSError() } | ||
| } | ||
|
|
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| func decompress(_ data: Data, finish: Bool) throws -> Data { | ||
| return try data.withUnsafeBytes { (bytes:UnsafePointer<UInt8>) -> Data in | ||
| return try decompress(bytes: bytes, count: data.count, finish: finish) | ||
| } | ||
| } | ||
|
|
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| func decompress(bytes: UnsafePointer<UInt8>, count: Int, finish: Bool) throws -> Data { | ||
| var decompressed = Data() | ||
| try decompress(bytes: bytes, count: count, out: &decompressed) | ||
|
|
||
| if finish { | ||
| let tail:[UInt8] = [0x00, 0x00, 0xFF, 0xFF] | ||
| try decompress(bytes: tail, count: tail.count, out: &decompressed) | ||
| } | ||
|
|
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| return decompressed | ||
|
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| } | ||
|
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| private func decompress(bytes: UnsafePointer<UInt8>, count: Int, out:inout Data) throws { | ||
| var res:CInt = 0 | ||
| strm.next_in = UnsafeMutablePointer<UInt8>(mutating: bytes) | ||
| strm.avail_in = CUnsignedInt(count) | ||
|
|
||
| repeat { | ||
| strm.next_out = UnsafeMutablePointer<UInt8>(&buffer) | ||
| strm.avail_out = CUnsignedInt(buffer.count) | ||
|
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| res = inflate(&strm, 0) | ||
|
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| let byteCount = buffer.count - Int(strm.avail_out) | ||
| out.append(buffer, count: byteCount) | ||
| } while res == Z_OK && strm.avail_out == 0 | ||
|
|
||
| guard (res == Z_OK && strm.avail_out > 0) | ||
| || (res == Z_BUF_ERROR && Int(strm.avail_out) == buffer.count) | ||
| else { | ||
| throw NSError(domain: WebSocket.ErrorDomain, code: Int(WebSocket.InternalErrorCode.compressionError.rawValue), userInfo: nil) | ||
| } | ||
| } | ||
|
|
||
| private func teardownInflate() { | ||
| if inflateInitialized, Z_OK == inflateEnd(&strm) { | ||
| inflateInitialized = false | ||
| } | ||
| } | ||
|
|
||
| deinit { | ||
| teardownInflate() | ||
| } | ||
| } | ||
|
|
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| class Compressor { | ||
| private var strm = z_stream() | ||
| private var buffer = [UInt8](repeating: 0, count: 0x2000) | ||
| private var deflateInitialized = false | ||
| private let windowBits:Int | ||
|
|
||
| init?(windowBits: Int) { | ||
| self.windowBits = windowBits | ||
| guard initDeflate() else { return nil } | ||
| } | ||
|
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| private func initDeflate() -> Bool { | ||
| if Z_OK == deflateInit2_(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED, | ||
| -CInt(windowBits), 8, Z_DEFAULT_STRATEGY, | ||
| ZLIB_VERSION, CInt(MemoryLayout<z_stream>.size)) | ||
| { | ||
| deflateInitialized = true | ||
| return true | ||
| } | ||
| return false | ||
| } | ||
|
|
||
| func reset() throws { | ||
| teardownDeflate() | ||
| guard initDeflate() else { throw NSError() } | ||
| } | ||
|
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| func compress(_ data: Data) throws -> Data { | ||
| var compressed = Data() | ||
| var res:CInt = 0 | ||
| data.withUnsafeBytes { (ptr:UnsafePointer<UInt8>) -> Void in | ||
| strm.next_in = UnsafeMutablePointer<UInt8>(mutating: ptr) | ||
| strm.avail_in = CUnsignedInt(data.count) | ||
|
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| repeat { | ||
| strm.next_out = UnsafeMutablePointer<UInt8>(&buffer) | ||
| strm.avail_out = CUnsignedInt(buffer.count) | ||
|
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| res = deflate(&strm, Z_SYNC_FLUSH) | ||
|
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| let byteCount = buffer.count - Int(strm.avail_out) | ||
| compressed.append(buffer, count: byteCount) | ||
| } | ||
| while res == Z_OK && strm.avail_out == 0 | ||
|
|
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| } | ||
|
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| guard res == Z_OK && strm.avail_out > 0 | ||
| || (res == Z_BUF_ERROR && Int(strm.avail_out) == buffer.count) | ||
| else { | ||
| throw NSError(domain: WebSocket.ErrorDomain, code: Int(WebSocket.InternalErrorCode.compressionError.rawValue), userInfo: nil) | ||
| } | ||
|
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| compressed.removeLast(4) | ||
| return compressed | ||
| } | ||
|
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| private func teardownDeflate() { | ||
| if deflateInitialized, Z_OK == deflateEnd(&strm) { | ||
| deflateInitialized = false | ||
| } | ||
| } | ||
|
|
||
| deinit { | ||
| teardownDeflate() | ||
| } | ||
| } | ||
|
|
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