forked from alexwinston/ExternalAccessory
/
EAOutputStream.m
111 lines (84 loc) · 2.72 KB
/
EAOutputStream.m
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//
// EAOutputStream.m
// ExternalAccessory
//
// Created by Alex Winston on 8/16/09.
// Copyright 2009 __MyCompanyName__. All rights reserved.
//
#import "EAOutputStream.h"
#import "EAAccessory.h"
#import "EASession.h"
#import "EAAudioPlayer.h"
@interface EAOutputStream (Private)
EAAudioPlayer *_audioPlayer;
@end
@implementation EAOutputStream
- (id)initWithAccessory:(id)accessory forSession:(id)session {
if( !(self=[super init]) )
return nil;
_accessory = [accessory retain];
_session = [session retain];
_streamStatus = NSStreamStatusNotOpen;
// ???: Retain reference to EAAudioPlayer so synchronized calls to sharedAudioPlayer aren't made during write
_audioPlayer = [[EAAudioPlayer sharedAudioPlayer] retain];
return self;
}
- (void)setDelegate:(id)delegate {
// ???: Research NSStreamEventEndEncountered
// [delegate stream:self handleEvent:NSStreamEventEndEncountered];
_delegate = delegate;
if ([_delegate respondsToSelector:@selector(stream:handleEvent:)])
_delegateRespondsToStreamHandleEvent = YES;
}
- (BOOL)hasSpaceAvailable {
return _hasSpaceAvailable;
}
- (unsigned int)streamStatus {
return _streamStatus;
}
- (void)open {
if (_streamStatus == NSStreamStatusOpen)
return;
_streamStatus = NSStreamStatusOpening;
// TODO: Send data passthrough command
//[_audioPlayer start];
_streamStatus = NSStreamStatusOpen;
if (_delegateRespondsToStreamHandleEvent)
[_delegate stream:(void *)self handleEvent:NSStreamEventOpenCompleted];
}
- (void)close {
//[_audioPlayer stop];
_streamStatus = NSStreamStatusClosed;
}
// TODO: Do not enqueueData if the player isn't started
- (int)write:(const char *)chars maxLength:(unsigned int)length {
if (_streamStatus != NSStreamStatusOpen)
return 0;
_streamStatus = NSStreamStatusWriting;
// TODO: Test the enqueueData buffer size to determine hasSpaceAvailable
for (int i = 0; i < 10; i++)
[_audioPlayer enqueueData:1.0f]; // Mark
// NOTE: Asynchronous serial communication http://en.wikipedia.org/wiki/Stop_bit
for (int i = 0; i < length; i++) {
for (int j = 0; j < 5; j++)
[_audioPlayer enqueueData:-1.0f]; // Start bit
// Most serial communications designs send the data bits within each byte LSB (Least Significant Bit) first.
// This standard is also referred to as "little endian".
for (int j = 0; j <= CHAR_BIT - 1; j++) {
for (int k = 0; k < 5; k++)
[_audioPlayer enqueueData:chars[i] & (1 << j) ? 1.0f : -1.0f]; // 8 data bits
}
for (int j = 0; j < 5; j++)
[_audioPlayer enqueueData:1.0f]; // Stop bit
}
_streamStatus = NSStreamStatusOpen;
// TODO: Check the number of bits enqueued
return length;
}
- (void)dealloc {
[_accessory release];
[_session release];
[_audioPlayer release];
[super dealloc];
}
@end