зеркало из https://github.com/nextcloud/talk-ios.git
99 строки
3.9 KiB
Objective-C
99 строки
3.9 KiB
Objective-C
/*
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* Copyright 2015 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#import "ARDSDPUtils.h"
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#import "WebRTC/RTCLogging.h"
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#import "WebRTC/RTCSessionDescription.h"
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@implementation ARDSDPUtils
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+ (RTCSessionDescription *)
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descriptionForDescription:(RTCSessionDescription *)description
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preferredVideoCodec:(NSString *)codec {
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NSString *sdpString = description.sdp;
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NSString *lineSeparator = @"\n";
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NSString *mLineSeparator = @" ";
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// Copied from PeerConnectionClient.java.
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// TODO(tkchin): Move this to a shared C++ file.
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NSMutableArray *lines =
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[NSMutableArray arrayWithArray:
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[sdpString componentsSeparatedByString:lineSeparator]];
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// Find the line starting with "m=video".
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NSInteger mLineIndex = -1;
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for (NSInteger i = 0; i < lines.count; ++i) {
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if ([lines[i] hasPrefix:@"m=video"]) {
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mLineIndex = i;
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break;
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}
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}
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if (mLineIndex == -1) {
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RTCLog(@"No m=video line, so can't prefer %@", codec);
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return description;
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}
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// An array with all payload types with name |codec|. The payload types are
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// integers in the range 96-127, but they are stored as strings here.
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NSMutableArray *codecPayloadTypes = [[NSMutableArray alloc] init];
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// a=rtpmap:<payload type> <encoding name>/<clock rate>
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// [/<encoding parameters>]
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NSString *pattern =
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[NSString stringWithFormat:@"^a=rtpmap:(\\d+) %@(/\\d+)+[\r]?$", codec];
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NSRegularExpression *regex =
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[NSRegularExpression regularExpressionWithPattern:pattern
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options:0
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error:nil];
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for (NSString *line in lines) {
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NSTextCheckingResult *codecMatches =
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[regex firstMatchInString:line
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options:0
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range:NSMakeRange(0, line.length)];
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if (codecMatches) {
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[codecPayloadTypes
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addObject:[line substringWithRange:[codecMatches rangeAtIndex:1]]];
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}
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}
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if ([codecPayloadTypes count] == 0) {
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RTCLog(@"No payload types with name %@", codec);
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return description;
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}
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NSArray *origMLineParts =
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[lines[mLineIndex] componentsSeparatedByString:mLineSeparator];
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// The format of ML should be: m=<media> <port> <proto> <fmt> ...
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const int kHeaderLength = 3;
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if (origMLineParts.count <= kHeaderLength) {
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RTCLogWarning(@"Wrong SDP media description format: %@", lines[mLineIndex]);
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return description;
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}
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// Split the line into header and payloadTypes.
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NSRange headerRange = NSMakeRange(0, kHeaderLength);
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NSRange payloadRange =
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NSMakeRange(kHeaderLength, origMLineParts.count - kHeaderLength);
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NSArray *header = [origMLineParts subarrayWithRange:headerRange];
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NSMutableArray *payloadTypes = [NSMutableArray
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arrayWithArray:[origMLineParts subarrayWithRange:payloadRange]];
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// Reconstruct the line with |codecPayloadTypes| moved to the beginning of the
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// payload types.
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NSMutableArray *newMLineParts = [NSMutableArray arrayWithCapacity:origMLineParts.count];
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[newMLineParts addObjectsFromArray:header];
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[newMLineParts addObjectsFromArray:codecPayloadTypes];
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[payloadTypes removeObjectsInArray:codecPayloadTypes];
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[newMLineParts addObjectsFromArray:payloadTypes];
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NSString *newMLine = [newMLineParts componentsJoinedByString:mLineSeparator];
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[lines replaceObjectAtIndex:mLineIndex
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withObject:newMLine];
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NSString *mangledSdpString = [lines componentsJoinedByString:lineSeparator];
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return [[RTCSessionDescription alloc] initWithType:description.type
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sdp:mangledSdpString];
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}
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@end
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