cog/Audio/CogPluginMulti.m

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//
// CogPluginMulti.m
// CogAudio
//
// Created by Christopher Snowhill on 10/21/13.
//
//
#import "CogPluginMulti.h"
NSArray *sortClassesByPriority(NSArray *theClasses) {
NSMutableArray *sortedClasses = [NSMutableArray arrayWithArray:theClasses];
[sortedClasses sortUsingComparator:
^NSComparisonResult(id obj1, id obj2) {
NSString *classString1 = (NSString *)obj1;
NSString *classString2 = (NSString *)obj2;
Class class1 = NSClassFromString(classString1);
Class class2 = NSClassFromString(classString2);
float priority1 = [class1 priority];
float priority2 = [class2 priority];
if(priority1 == priority2)
return NSOrderedSame;
else if(priority1 > priority2)
return NSOrderedAscending;
else
return NSOrderedDescending;
}];
return sortedClasses;
}
@interface CogDecoderMulti (Private)
- (void)registerObservers;
- (void)removeObservers;
- (void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context;
@end
@implementation CogDecoderMulti
+ (NSArray *)mimeTypes {
return nil;
}
+ (NSArray *)fileTypes {
return nil;
}
+ (float)priority {
return -1.0;
}
+ (NSArray *)fileTypeAssociations {
return nil;
}
- (id)initWithDecoders:(NSArray *)decoders {
self = [super init];
if(self) {
theDecoders = sortClassesByPriority(decoders);
theDecoder = nil;
}
return self;
}
- (NSDictionary *)properties {
if(theDecoder != nil) return [theDecoder properties];
return nil;
}
- (NSDictionary *)metadata {
if(theDecoder != nil) return [theDecoder metadata];
return @{};
}
- (int)readAudio:(void *)buffer frames:(UInt32)frames {
if(theDecoder != nil) return [theDecoder readAudio:buffer frames:frames];
return 0;
}
- (BOOL)open:(id<CogSource>)source {
for(NSString *classString in theDecoders) {
Class decoder = NSClassFromString(classString);
theDecoder = [[decoder alloc] init];
[self registerObservers];
if([theDecoder open:source])
return YES;
[self removeObservers];
// HTTP reader supports limited rewinding
[source seek:0 whence:SEEK_SET];
}
theDecoder = nil;
return NO;
}
- (long)seek:(long)frame {
if(theDecoder != nil) return [theDecoder seek:frame];
return -1;
}
- (void)close {
if(theDecoder != nil) {
[self removeObservers];
[theDecoder close];
theDecoder = nil;
}
}
- (void)registerObservers {
[theDecoder addObserver:self
forKeyPath:@"properties"
options:(NSKeyValueObservingOptionNew)
context:NULL];
[theDecoder addObserver:self
forKeyPath:@"metadata"
options:(NSKeyValueObservingOptionNew)
context:NULL];
}
- (void)removeObservers {
[theDecoder removeObserver:self forKeyPath:@"properties"];
[theDecoder removeObserver:self forKeyPath:@"metadata"];
}
- (BOOL)setTrack:(NSURL *)track {
if(theDecoder != nil && [theDecoder respondsToSelector:@selector(setTrack:)]) return [theDecoder setTrack:track];
return NO;
}
- (void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context {
[self willChangeValueForKey:keyPath];
[self didChangeValueForKey:keyPath];
}
@end
@implementation CogContainerMulti
+ (NSArray *)urlsForContainerURL:(NSURL *)url containers:(NSArray *)containers {
NSArray *sortedContainers = sortClassesByPriority(containers);
for(NSString *classString in sortedContainers) {
Class container = NSClassFromString(classString);
NSArray *urls = [container urlsForContainerURL:url];
if([urls count])
return urls;
}
return nil;
}
@end
@implementation CogMetadataReaderMulti
+ (NSDictionary *)metadataForURL:(NSURL *)url readers:(NSArray *)readers {
NSArray *sortedReaders = sortClassesByPriority(readers);
for(NSString *classString in sortedReaders) {
Class reader = NSClassFromString(classString);
NSDictionary *data = [reader metadataForURL:url];
if([data count])
return data;
}
return nil;
}
@end
@implementation CogPropertiesReaderMulti
+ (NSDictionary *)propertiesForSource:(id<CogSource>)source readers:(NSArray *)readers {
NSArray *sortedReaders = sortClassesByPriority(readers);
for(NSString *classString in sortedReaders) {
Class reader = NSClassFromString(classString);
NSDictionary *data = [reader propertiesForSource:source];
if([data count])
return data;
if([source seekable])
[source seek:0 whence:SEEK_SET];
}
return nil;
}
@end