Copy a portion of an NSMutableData to a new NSMutableData object
I am reading in a large file into an NSMutableData object.
var lBuffer : NSMutableData = try NSMutableData(contentsOfFile: pFilePath)
I would like to get a portion of the NSMutableData object to work with at a time. So I am trying to use .subdata(with: NSRange), but am getting an error.
var lBufferChunk : NSMutableData = lBuffer.subdata(with: NSRange(location: 0, length: lSizeOfChunk)) as! NSMutableData
The error I get is:
Could not cast value of type 'NSSubrangeData' (0x7fffa6ea3ef8) to 'NSMutableData' (0x7fffa6a403f8)
According to the documentation, .subdata(with: NSRange) should return a Data object.
How can I get it to a Data object to cast it back to NSMutableData? Or is there a better way of getting a portion/fragment out of a large NSMutableData?
swift macos nsdata
edited Nov 21 '18 at 3:29
rmaddy
238k27310376
asked Nov 21 '18 at 2:12
Tagnal
375
add a comment |
I am reading in a large file into an NSMutableData object.
var lBuffer : NSMutableData = try NSMutableData(contentsOfFile: pFilePath)
I would like to get a portion of the NSMutableData object to work with at a time. So I am trying to use .subdata(with: NSRange), but am getting an error.
var lBufferChunk : NSMutableData = lBuffer.subdata(with: NSRange(location: 0, length: lSizeOfChunk)) as! NSMutableData
The error I get is:
Could not cast value of type 'NSSubrangeData' (0x7fffa6ea3ef8) to 'NSMutableData' (0x7fffa6a403f8)
According to the documentation, .subdata(with: NSRange) should return a Data object.
How can I get it to a Data object to cast it back to NSMutableData? Or is there a better way of getting a portion/fragment out of a large NSMutableData?
swift macos nsdata
edited Nov 21 '18 at 3:29
rmaddy
238k27310376
asked Nov 21 '18 at 2:12
Tagnal
375
add a comment |
I am reading in a large file into an NSMutableData object.
var lBuffer : NSMutableData = try NSMutableData(contentsOfFile: pFilePath)
I would like to get a portion of the NSMutableData object to work with at a time. So I am trying to use .subdata(with: NSRange), but am getting an error.
var lBufferChunk : NSMutableData = lBuffer.subdata(with: NSRange(location: 0, length: lSizeOfChunk)) as! NSMutableData
The error I get is:
Could not cast value of type 'NSSubrangeData' (0x7fffa6ea3ef8) to 'NSMutableData' (0x7fffa6a403f8)
According to the documentation, .subdata(with: NSRange) should return a Data object.
How can I get it to a Data object to cast it back to NSMutableData? Or is there a better way of getting a portion/fragment out of a large NSMutableData?
swift macos nsdata
edited Nov 21 '18 at 3:29
rmaddy
238k27310376
asked Nov 21 '18 at 2:12
Tagnal
375
I am reading in a large file into an NSMutableData object.
var lBuffer : NSMutableData = try NSMutableData(contentsOfFile: pFilePath)
I would like to get a portion of the NSMutableData object to work with at a time. So I am trying to use .subdata(with: NSRange), but am getting an error.
var lBufferChunk : NSMutableData = lBuffer.subdata(with: NSRange(location: 0, length: lSizeOfChunk)) as! NSMutableData
The error I get is:
Could not cast value of type 'NSSubrangeData' (0x7fffa6ea3ef8) to 'NSMutableData' (0x7fffa6a403f8)
According to the documentation, .subdata(with: NSRange) should return a Data object.
How can I get it to a Data object to cast it back to NSMutableData? Or is there a better way of getting a portion/fragment out of a large NSMutableData?
swift macos nsdata
swift macos nsdata
edited Nov 21 '18 at 3:29
rmaddy
238k27310376
asked Nov 21 '18 at 2:12
Tagnal
375
edited Nov 21 '18 at 3:29
rmaddy
238k27310376
asked Nov 21 '18 at 2:12
Tagnal
375
edited Nov 21 '18 at 3:29
rmaddy
238k27310376
edited Nov 21 '18 at 3:29
rmaddy
238k27310376
edited Nov 21 '18 at 3:29
rmaddy
238k27310376
238k27310376
asked Nov 21 '18 at 2:12
Tagnal
375
asked Nov 21 '18 at 2:12
Tagnal
375
asked Nov 21 '18 at 2:12
Tagnal
375
375
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
If you really wanted to, you could cast the result of calling lBuffer.subdata to an NSData and then call mutableCopy() and force-cast the result to NSMutableData. But don't! Don't even use NSData or NSMutableData in the first place. This is Swift. Use Data.
var lBuffer = Data(contentsOf: myFileURL)
Now just call subdata(in:)
var lBufferChunk = lBuffer.subdata(in: myRange)
Or subscript
var lBufferChunk = lBuffer[myRange]
The var makes it mutable.
answered Nov 21 '18 at 2:32
matt
324k45523722
or simplylBuffer[myRange]
– Leo Dabus
Nov 21 '18 at 3:29
The reason why I'm trying to use NSMutableData is because I need to pass it to an objective-c function that takes in a NSMutableData object.
– Tagnal
Nov 21 '18 at 20:23
What a strange function that would be! But if that's really the case, you can pass a Data to that function as I already explained. For example to passlBufferChunkwhere an NSMutableData is expected you would do what I already said: cast it to NSData and then callmutableCopy()and force-cast to NSMutableData.
– matt
Nov 21 '18 at 21:00
add a comment |
So, I went a different route to solve my issue. As you can see, I wanted to read in a file to a NSMutableData object, but wanted to copy smaller portions of it at a time (in the case of large files). Instead of reading a range of one Data object and passing it to the other, I decided to use an input stream instead.
var lInputStream : InputStream = InputStream(fileAtPath: pFilePath)!
var lBuffer : UnsafeMutablePointer<UInt8> = UnsafeMutablePointer<UInt8>.allocate(capacity: lBufferSize)
lInputStream.open()
while lInputStream.hasBytesAvailable {
let read = lInputStream.read(lBuffer, maxLength: lBufferSize)
var dataChunk = NSMutableData(length: 0)
dataChunk?.append(lBuffer, length: read)
...
}
lInputStream.close()
Matt's answer is correct for the way the question was originally asked and I've marked it as so. Just wanted to share what I ended up doing in the end.
answered Nov 27 '18 at 22:44
Tagnal
375
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
If you really wanted to, you could cast the result of calling lBuffer.subdata to an NSData and then call mutableCopy() and force-cast the result to NSMutableData. But don't! Don't even use NSData or NSMutableData in the first place. This is Swift. Use Data.
var lBuffer = Data(contentsOf: myFileURL)
Now just call subdata(in:)
var lBufferChunk = lBuffer.subdata(in: myRange)
Or subscript
var lBufferChunk = lBuffer[myRange]
The var makes it mutable.
answered Nov 21 '18 at 2:32
matt
324k45523722
or simplylBuffer[myRange]
– Leo Dabus
Nov 21 '18 at 3:29
The reason why I'm trying to use NSMutableData is because I need to pass it to an objective-c function that takes in a NSMutableData object.
– Tagnal
Nov 21 '18 at 20:23
What a strange function that would be! But if that's really the case, you can pass a Data to that function as I already explained. For example to passlBufferChunkwhere an NSMutableData is expected you would do what I already said: cast it to NSData and then callmutableCopy()and force-cast to NSMutableData.
– matt
Nov 21 '18 at 21:00
add a comment |
If you really wanted to, you could cast the result of calling lBuffer.subdata to an NSData and then call mutableCopy() and force-cast the result to NSMutableData. But don't! Don't even use NSData or NSMutableData in the first place. This is Swift. Use Data.
var lBuffer = Data(contentsOf: myFileURL)
Now just call subdata(in:)
var lBufferChunk = lBuffer.subdata(in: myRange)
Or subscript
var lBufferChunk = lBuffer[myRange]
The var makes it mutable.
answered Nov 21 '18 at 2:32
matt
324k45523722
or simplylBuffer[myRange]
– Leo Dabus
Nov 21 '18 at 3:29
The reason why I'm trying to use NSMutableData is because I need to pass it to an objective-c function that takes in a NSMutableData object.
– Tagnal
Nov 21 '18 at 20:23
What a strange function that would be! But if that's really the case, you can pass a Data to that function as I already explained. For example to passlBufferChunkwhere an NSMutableData is expected you would do what I already said: cast it to NSData and then callmutableCopy()and force-cast to NSMutableData.
– matt
Nov 21 '18 at 21:00
add a comment |
If you really wanted to, you could cast the result of calling lBuffer.subdata to an NSData and then call mutableCopy() and force-cast the result to NSMutableData. But don't! Don't even use NSData or NSMutableData in the first place. This is Swift. Use Data.
var lBuffer = Data(contentsOf: myFileURL)
Now just call subdata(in:)
var lBufferChunk = lBuffer.subdata(in: myRange)
Or subscript
var lBufferChunk = lBuffer[myRange]
The var makes it mutable.
answered Nov 21 '18 at 2:32
matt
324k45523722
If you really wanted to, you could cast the result of calling lBuffer.subdata to an NSData and then call mutableCopy() and force-cast the result to NSMutableData. But don't! Don't even use NSData or NSMutableData in the first place. This is Swift. Use Data.
var lBuffer = Data(contentsOf: myFileURL)
Now just call subdata(in:)
var lBufferChunk = lBuffer.subdata(in: myRange)
Or subscript
var lBufferChunk = lBuffer[myRange]
The var makes it mutable.
answered Nov 21 '18 at 2:32
matt
324k45523722
edited Nov 21 '18 at 5:03
answered Nov 21 '18 at 2:32
matt
324k45523722
answered Nov 21 '18 at 2:32
matt
324k45523722
answered Nov 21 '18 at 2:32
matt
324k45523722
324k45523722
or simplylBuffer[myRange]
– Leo Dabus
Nov 21 '18 at 3:29
The reason why I'm trying to use NSMutableData is because I need to pass it to an objective-c function that takes in a NSMutableData object.
– Tagnal
Nov 21 '18 at 20:23
What a strange function that would be! But if that's really the case, you can pass a Data to that function as I already explained. For example to passlBufferChunkwhere an NSMutableData is expected you would do what I already said: cast it to NSData and then callmutableCopy()and force-cast to NSMutableData.
– matt
Nov 21 '18 at 21:00
add a comment |
or simplylBuffer[myRange]
– Leo Dabus
Nov 21 '18 at 3:29
The reason why I'm trying to use NSMutableData is because I need to pass it to an objective-c function that takes in a NSMutableData object.
– Tagnal
Nov 21 '18 at 20:23
What a strange function that would be! But if that's really the case, you can pass a Data to that function as I already explained. For example to passlBufferChunkwhere an NSMutableData is expected you would do what I already said: cast it to NSData and then callmutableCopy()and force-cast to NSMutableData.
– matt
Nov 21 '18 at 21:00
or simply
lBuffer[myRange]– Leo Dabus
Nov 21 '18 at 3:29
or simply
lBuffer[myRange]– Leo Dabus
Nov 21 '18 at 3:29
The reason why I'm trying to use NSMutableData is because I need to pass it to an objective-c function that takes in a NSMutableData object.
– Tagnal
Nov 21 '18 at 20:23
The reason why I'm trying to use NSMutableData is because I need to pass it to an objective-c function that takes in a NSMutableData object.
– Tagnal
Nov 21 '18 at 20:23
What a strange function that would be! But if that's really the case, you can pass a Data to that function as I already explained. For example to pass
lBufferChunk where an NSMutableData is expected you would do what I already said: cast it to NSData and then call mutableCopy() and force-cast to NSMutableData.– matt
Nov 21 '18 at 21:00
What a strange function that would be! But if that's really the case, you can pass a Data to that function as I already explained. For example to pass
lBufferChunk where an NSMutableData is expected you would do what I already said: cast it to NSData and then call mutableCopy() and force-cast to NSMutableData.– matt
Nov 21 '18 at 21:00
add a comment |
So, I went a different route to solve my issue. As you can see, I wanted to read in a file to a NSMutableData object, but wanted to copy smaller portions of it at a time (in the case of large files). Instead of reading a range of one Data object and passing it to the other, I decided to use an input stream instead.
var lInputStream : InputStream = InputStream(fileAtPath: pFilePath)!
var lBuffer : UnsafeMutablePointer<UInt8> = UnsafeMutablePointer<UInt8>.allocate(capacity: lBufferSize)
lInputStream.open()
while lInputStream.hasBytesAvailable {
let read = lInputStream.read(lBuffer, maxLength: lBufferSize)
var dataChunk = NSMutableData(length: 0)
dataChunk?.append(lBuffer, length: read)
...
}
lInputStream.close()
Matt's answer is correct for the way the question was originally asked and I've marked it as so. Just wanted to share what I ended up doing in the end.
answered Nov 27 '18 at 22:44
Tagnal
375
add a comment |
So, I went a different route to solve my issue. As you can see, I wanted to read in a file to a NSMutableData object, but wanted to copy smaller portions of it at a time (in the case of large files). Instead of reading a range of one Data object and passing it to the other, I decided to use an input stream instead.
var lInputStream : InputStream = InputStream(fileAtPath: pFilePath)!
var lBuffer : UnsafeMutablePointer<UInt8> = UnsafeMutablePointer<UInt8>.allocate(capacity: lBufferSize)
lInputStream.open()
while lInputStream.hasBytesAvailable {
let read = lInputStream.read(lBuffer, maxLength: lBufferSize)
var dataChunk = NSMutableData(length: 0)
dataChunk?.append(lBuffer, length: read)
...
}
lInputStream.close()
Matt's answer is correct for the way the question was originally asked and I've marked it as so. Just wanted to share what I ended up doing in the end.
answered Nov 27 '18 at 22:44
Tagnal
375
add a comment |
So, I went a different route to solve my issue. As you can see, I wanted to read in a file to a NSMutableData object, but wanted to copy smaller portions of it at a time (in the case of large files). Instead of reading a range of one Data object and passing it to the other, I decided to use an input stream instead.
var lInputStream : InputStream = InputStream(fileAtPath: pFilePath)!
var lBuffer : UnsafeMutablePointer<UInt8> = UnsafeMutablePointer<UInt8>.allocate(capacity: lBufferSize)
lInputStream.open()
while lInputStream.hasBytesAvailable {
let read = lInputStream.read(lBuffer, maxLength: lBufferSize)
var dataChunk = NSMutableData(length: 0)
dataChunk?.append(lBuffer, length: read)
...
}
lInputStream.close()
Matt's answer is correct for the way the question was originally asked and I've marked it as so. Just wanted to share what I ended up doing in the end.
answered Nov 27 '18 at 22:44
Tagnal
375
So, I went a different route to solve my issue. As you can see, I wanted to read in a file to a NSMutableData object, but wanted to copy smaller portions of it at a time (in the case of large files). Instead of reading a range of one Data object and passing it to the other, I decided to use an input stream instead.
var lInputStream : InputStream = InputStream(fileAtPath: pFilePath)!
var lBuffer : UnsafeMutablePointer<UInt8> = UnsafeMutablePointer<UInt8>.allocate(capacity: lBufferSize)
lInputStream.open()
while lInputStream.hasBytesAvailable {
let read = lInputStream.read(lBuffer, maxLength: lBufferSize)
var dataChunk = NSMutableData(length: 0)
dataChunk?.append(lBuffer, length: read)
...
}
lInputStream.close()
Matt's answer is correct for the way the question was originally asked and I've marked it as so. Just wanted to share what I ended up doing in the end.
answered Nov 27 '18 at 22:44
Tagnal
375
answered Nov 27 '18 at 22:44
Tagnal
375
answered Nov 27 '18 at 22:44
Tagnal
375
answered Nov 27 '18 at 22:44
Tagnal
375
375
add a comment |
add a comment |
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