JSJP_Student/Pods/DOUAudioStreamer/src/DOUAudioPlaybackItem.m

/* vim: set ft=objc fenc=utf-8 sw=2 ts=2 et: */
/*
 *  DOUAudioStreamer - A Core Audio based streaming audio player for iOS/Mac:
 *
 *      https://github.com/douban/DOUAudioStreamer
 *
 *  Copyright 2013-2016 Douban Inc.  All rights reserved.
 *
 *  Use and distribution licensed under the BSD license.  See
 *  the LICENSE file for full text.
 *
 *  Authors:
 *      Chongyu Zhu <i@lembacon.com>
 *
 */

#import "DOUAudioPlaybackItem.h"
#import "DOUAudioFileProvider.h"
#import "DOUAudioFilePreprocessor.h"

@interface DOUAudioPlaybackItem () {
@private
  DOUAudioFileProvider *_fileProvider;
  DOUAudioFilePreprocessor *_filePreprocessor;
  AudioFileID _fileID;
  AudioStreamBasicDescription _fileFormat;
  NSUInteger _bitRate;
  NSUInteger _dataOffset;
  NSUInteger _estimatedDuration;
}
@end

@implementation DOUAudioPlaybackItem

@synthesize fileProvider = _fileProvider;
@synthesize filePreprocessor = _filePreprocessor;
@synthesize fileID = _fileID;
@synthesize fileFormat = _fileFormat;
@synthesize bitRate = _bitRate;
@synthesize dataOffset = _dataOffset;
@synthesize estimatedDuration = _estimatedDuration;

- (id <DOUAudioFile>)audioFile
{
  return [_fileProvider audioFile];
}

- (NSURL *)cachedURL
{
  return [_fileProvider cachedURL];
}

- (NSData *)mappedData
{
  return [_fileProvider mappedData];
}

- (BOOL)isOpened
{
  return _fileID != NULL;
}

static OSStatus audio_file_read(void *inClientData,
                                SInt64 inPosition,
                                UInt32 requestCount,
                                void *buffer, 
                                UInt32 *actualCount)
{
  __unsafe_unretained DOUAudioPlaybackItem *item = (__bridge DOUAudioPlaybackItem *)inClientData;

  if (inPosition + requestCount > [[item mappedData] length]) {
    if (inPosition >= [[item mappedData] length]) {
      *actualCount = 0;
    }
    else {
      *actualCount = (UInt32)((SInt64)[[item mappedData] length] - inPosition);
    }
  }
  else {
    *actualCount = requestCount;
  }

  if (*actualCount == 0) {
    return noErr;
  }

  if ([item filePreprocessor] == nil) {
    memcpy(buffer, (uint8_t *)[[item mappedData] bytes] + inPosition, *actualCount);
  }
  else {
    NSData *input = [NSData dataWithBytesNoCopy:(uint8_t *)[[item mappedData] bytes] + inPosition
                                         length:*actualCount
                                   freeWhenDone:NO];
    NSData *output = [[item filePreprocessor] handleData:input offset:(NSUInteger)inPosition];
    memcpy(buffer, [output bytes], [output length]);
  }

  return noErr;
}

static SInt64 audio_file_get_size(void *inClientData)
{
  __unsafe_unretained DOUAudioPlaybackItem *item = (__bridge DOUAudioPlaybackItem *)inClientData;
  return (SInt64)[[item mappedData] length];
}

- (BOOL)_openWithFileTypeHint:(AudioFileTypeID)fileTypeHint
{
  OSStatus status;
  status = AudioFileOpenWithCallbacks((__bridge void *)self,
                                      audio_file_read,
                                      NULL,
                                      audio_file_get_size,
                                      NULL,
                                      fileTypeHint,
                                      &_fileID);

  return status == noErr;
}

- (BOOL)_openWithFallbacks
{
  NSArray *fallbackTypeIDs = [self _fallbackTypeIDs];
  for (NSNumber *typeIDNumber in fallbackTypeIDs) {
    AudioFileTypeID typeID = (AudioFileTypeID)[typeIDNumber unsignedLongValue];
    if ([self _openWithFileTypeHint:typeID]) {
      return YES;
    }
  }

  return NO;
}

- (NSArray *)_fallbackTypeIDs
{
  NSMutableArray *fallbackTypeIDs = [NSMutableArray array];
  NSMutableSet *fallbackTypeIDSet = [NSMutableSet set];

  struct {
    CFStringRef specifier;
    AudioFilePropertyID propertyID;
  } properties[] = {
    { (__bridge CFStringRef)[_fileProvider mimeType], kAudioFileGlobalInfo_TypesForMIMEType },
    { (__bridge CFStringRef)[_fileProvider fileExtension], kAudioFileGlobalInfo_TypesForExtension }
  };

  const size_t numberOfProperties = sizeof(properties) / sizeof(properties[0]);

  for (size_t i = 0; i < numberOfProperties; ++i) {
    if (properties[i].specifier == NULL) {
      continue;
    }

    UInt32 outSize = 0;
    OSStatus status;

    status = AudioFileGetGlobalInfoSize(properties[i].propertyID,
                                        sizeof(properties[i].specifier),
                                        &properties[i].specifier,
                                        &outSize);
    if (status != noErr) {
      continue;
    }

    size_t count = outSize / sizeof(AudioFileTypeID);
    AudioFileTypeID *buffer = (AudioFileTypeID *)malloc(outSize);
    if (buffer == NULL) {
      continue;
    }

    status = AudioFileGetGlobalInfo(properties[i].propertyID,
                                    sizeof(properties[i].specifier),
                                    &properties[i].specifier,
                                    &outSize,
                                    buffer);
    if (status != noErr) {
      free(buffer);
      continue;
    }

    for (size_t j = 0; j < count; ++j) {
      NSNumber *tid = [NSNumber numberWithUnsignedLong:buffer[j]];
      if ([fallbackTypeIDSet containsObject:tid]) {
        continue;
      }

      [fallbackTypeIDs addObject:tid];
      [fallbackTypeIDSet addObject:tid];
    }

    free(buffer);
  }

  return fallbackTypeIDs;
}

- (BOOL)open
{
  if ([self isOpened]) {
    return YES;
  }

  if (![self _openWithFileTypeHint:0] &&
      ![self _openWithFallbacks]) {
    _fileID = NULL;
    return NO;
  }

  if (![self _fillFileFormat] ||
      ![self _fillMiscProperties]) {
    AudioFileClose(_fileID);
    _fileID = NULL;
    return NO;
  }

  return YES;
}

- (BOOL)_fillFileFormat
{
  UInt32 size;
  OSStatus status;

  status = AudioFileGetPropertyInfo(_fileID, kAudioFilePropertyFormatList, &size, NULL);
  if (status != noErr) {
    return NO;
  }

  UInt32 numFormats = size / sizeof(AudioFormatListItem);
  AudioFormatListItem *formatList = (AudioFormatListItem *)malloc(size);

  status = AudioFileGetProperty(_fileID, kAudioFilePropertyFormatList, &size, formatList);
  if (status != noErr) {
    free(formatList);
    return NO;
  }

  if (numFormats == 1) {
    _fileFormat = formatList[0].mASBD;
  }
  else {
    status = AudioFormatGetPropertyInfo(kAudioFormatProperty_DecodeFormatIDs, 0, NULL, &size);
    if (status != noErr) {
      free(formatList);
      return NO;
    }

    UInt32 numDecoders = size / sizeof(OSType);
    OSType *decoderIDS = (OSType *)malloc(size);

    status = AudioFormatGetProperty(kAudioFormatProperty_DecodeFormatIDs, 0, NULL, &size, decoderIDS);
    if (status != noErr) {
      free(formatList);
      free(decoderIDS);
      return NO;
    }

    UInt32 i;
    for (i = 0; i < numFormats; ++i) {
      OSType decoderID = formatList[i].mASBD.mFormatID;

      BOOL found = NO;
      for (UInt32 j = 0; j < numDecoders; ++j) {
        if (decoderID == decoderIDS[j]) {
          found = YES;
          break;
        }
      }

      if (found) {
        break;
      }
    }

    free(decoderIDS);

    if (i >= numFormats) {
      free(formatList);
      return NO;
    }

    _fileFormat = formatList[i].mASBD;
  }

  free(formatList);
  return YES;
}

- (BOOL)_fillMiscProperties
{
  UInt32 size;
  OSStatus status;

  UInt32 bitRate = 0;
  size = sizeof(bitRate);
  status = AudioFileGetProperty(_fileID, kAudioFilePropertyBitRate, &size, &bitRate);
  if (status != noErr) {
    return NO;
  }
  _bitRate = bitRate;

  SInt64 dataOffset = 0;
  size = sizeof(dataOffset);
  status = AudioFileGetProperty(_fileID, kAudioFilePropertyDataOffset, &size, &dataOffset);
  if (status != noErr) {
    return NO;
  }
  _dataOffset = (NSUInteger)dataOffset;

  Float64 estimatedDuration = 0.0;
  size = sizeof(estimatedDuration);
  status = AudioFileGetProperty(_fileID, kAudioFilePropertyEstimatedDuration, &size, &estimatedDuration);
  if (status != noErr) {
    return NO;
  }
  _estimatedDuration = estimatedDuration * 1000.0;

  return YES;
}

- (void)close
{
  if (![self isOpened]) {
    return;
  }

  AudioFileClose(_fileID);
  _fileID = NULL;
}

+ (instancetype)playbackItemWithFileProvider:(DOUAudioFileProvider *)fileProvider
{
  return [[[self class] alloc] initWithFileProvider:fileProvider];
}

- (instancetype)initWithFileProvider:(DOUAudioFileProvider *)fileProvider
{
  self = [super init];
  if (self) {
    _fileProvider = fileProvider;

    if ([[self audioFile] respondsToSelector:@selector(audioFilePreprocessor)]) {
      _filePreprocessor = [[self audioFile] audioFilePreprocessor];
    }
  }

  return self;
}

- (void)dealloc
{
  if ([self isOpened]) {
    [self close];
  }
}

@end