I need to split an audio or large image file in J2ME before uploading it. How can i split/ break a file in to pieces in JavaME.
What API for file loading do you use?
1)If FileConnection API you can load data by blocks. There is no problem in this case.
2)If you use Class.getResourceAsStream( String pathInsideJar ) you will have problems. Most of KVMs load resource fully before returning control to your code. So I see one way - to split big file into several small files before creating jar.
DataInputStream dis =
FileConnection.getDataInputStream();
byte[] buffer = new byte[2048];
int count;
int total = 0;
Vector v = new Vector();
ByteArrayOutputStream baos = new
ByteArrayOutputStream();
while( ( count = dis.read( buffer ) ) >= 0 )
{
total += count;
baos.write( buffer, 0, count );
if( total > 100000 )
{
baos.close();
byte[] data = baos.toByteArray();
v.addElement( data );
baos = new ByteArrayOutputStream();
}
}
So you will have Vector of several byte arrays. And you can send it one by one.
Or read all file data into one byte array and post this data by parts with shifting start position of sending data.
Related
I'm using the following code:
GcsService gcsService = GcsServiceFactory.createGcsService();
GcsFilename filename = new GcsFilename(BUCKETNAME, fileName);
GcsFileOptions options = new GcsFileOptions.Builder()
.mimeType(contentType)
.acl("public-read")
.addUserMetadata("myfield1", "my field value")
.build();
#SuppressWarnings("resource")
GcsOutputChannel outputChannel =
gcsService.createOrReplace(filename, options);
outputChannel.write(ByteBuffer.wrap(byteArray));
outputChannel.close();
The problem is that when I try to store video files, I have to store the file in the byteArray which could cause memory issues.
But I cannot find any interface to do the same with stream.
questions:
Should I worry about mem issues in the appengine srv, or are they capable of keeping a 1 min video in mem?
is it possible to use stream instead of byte array? how?
I'm reading the bytes as byte[] byteArray = IOUtils.toByteArray(stream); should I use the byte array as a real buffer and just read chunks and upload them to the GCS? how do I do that?
The amount of memory available depends on the appengine instance type you've configured. Streaming this data seems like a good idea if you can.
Not sure about the GcsService api, but looks like you can do this using the gcloud Storage api:
https://github.com/GoogleCloudPlatform/gcloud-java/blob/master/gcloud-java-storage/src/main/java/com/google/cloud/storage/Storage.java
This code might work (untested)...
final BlobInfo info = BlobInfo.builder(bucket.getBucketName(), "name").contentType("image/png").build();
final ReadableByteChannel src = Channels.newChannel(stream);
final WriteChannel dst = gcsStorage.writer(info);
fastChannelCopy(src, dst);
private void fastChannelCopy(final ReadableByteChannel src, final WritableByteChannel dest) throws IOException {
final ByteBuffer buffer = ByteBuffer.allocateDirect(16 * 1024);
while (src.read(buffer) != -1) {
buffer.flip(); // prepare the buffer to be drained
dest.write(buffer); // write to the channel, may block
// If partial transfer, shift remainder down
// If buffer is empty, same as doing clear()
buffer.compact();
}
// EOF will leave buffer in fill state
buffer.flip();
// make sure the buffer is fully drained.
while (buffer.hasRemaining()) {
dest.write(buffer);
}
}
I'm writing a program Which will concat multiple (mp4 format) to one file.But Problem is that my code only show last video file in merged file(m.mp4).The code which I am using is given below for description.
FileStream fs = new FileStream("m.mp4",FileMode.Append);
for (i = 1; i <= 3; i++)
{
//m1,m2,m3 are video mp4 files on my disk
var bytes = File.ReadAllBytes("m" + i + ".mp4");
fs.Write(bytes, 0, bytes.Length);
}
Console.WriteLine("Done!!");
My purpose is to parse text files and store information in respective tables.
I have to parse around 100 folders having more that 8000 files and whole size approximately 20GB.
When I tried to store whole file contents in a string, memory out exception was thrown.
That is
using (StreamReader objStream = new StreamReader(filename))
{
string fileDetails = objStream.ReadToEnd();
}
Hence I tried one logic like
using (StreamReader objStream = new StreamReader(filename))
{
// Getting total number of lines in a file
int fileLineCount = File.ReadLines(filename).Count();
if (fileLineCount < 90000)
{
fileDetails = objStream.ReadToEnd();
fileDetails = fileDetails.Replace(Environment.NewLine, "\n");
string[] fileInfo = fileDetails.ToString().Split('\n');
//call respective method for parsing and insertion
}
else
{
while ((firstLine = objStream.ReadLine()) != null)
{
lineCount++;
fileDetails = (fileDetails != string.Empty) ? string.Concat(fileDetails, "\n", firstLine)
: string.Concat(firstLine);
if (lineCount == 90000)
{
fileDetails = fileDetails.Replace(Environment.NewLine, "\n");
string[] fileInfo = fileDetails.ToString().Split('\n');
lineCount = 0;
//call respective method for parsing and insertion
}
}
//when content is 90057, to parse 57
if (lineCount < 90000 )
{
string[] fileInfo = fileDetails.ToString().Split('\n');
lineCount = 0;
//call respective method for parsing and insertion
}
}
}
Here 90,000 is the bulk size which is safe to process without giving out of memory exception for my case.
Still the process is taking more than 2 days for completion. I observed this is because of reading line by line.
Is there any better approach to handle this ?
Thanks in Advance :)
You can use a profiler to detect what sucks your performance. In this case it's obvious: disk access and string concatenation.
Do not read a file more than once. Let's take a look at your code. First of all, the line int fileLineCount = File.ReadLines(filename).Count(); means you read the whole file and discard what you've read. That's bad. Throw away your if (fileLineCount < 90000) and keep only else.
It almost doesn't matter if you read line-by-line in consecutive order or the whole file because reading is buffered in any case.
Avoid string concatenation, especially for long strings.
fileDetails = fileDetails.Replace(Environment.NewLine, "\n");
string[] fileInfo = fileDetails.ToString().Split('\n');
It's really bad. You read the file line-by-line, why do you do this replacement/split? File.ReadLines() gives you a collection of all lines. Just pass it to your parsing routine.
If you'll do this properly I expect significant speedup. It can be optimized further by reading files in a separate thread while processing them in the main. But this is another story.
We're using "Google Cloud Storage Client Library" for app engine, with simply "GcsFileOptions.Builder.contentEncoding("gzip")" at file creation time, we got the following problem when reading the file:
com.google.appengine.tools.cloudstorage.NonRetriableException: java.lang.RuntimeException: com.google.appengine.tools.cloudstorage.SimpleGcsInputChannelImpl$1#1c07d21: Unexpected cause of ExecutionException
at com.google.appengine.tools.cloudstorage.RetryHelper.doRetry(RetryHelper.java:87)
at com.google.appengine.tools.cloudstorage.RetryHelper.runWithRetries(RetryHelper.java:129)
at com.google.appengine.tools.cloudstorage.RetryHelper.runWithRetries(RetryHelper.java:123)
at com.google.appengine.tools.cloudstorage.SimpleGcsInputChannelImpl.read(SimpleGcsInputChannelImpl.java:81)
...
Caused by: java.lang.RuntimeException: com.google.appengine.tools.cloudstorage.SimpleGcsInputChannelImpl$1#1c07d21: Unexpected cause of ExecutionException
at com.google.appengine.tools.cloudstorage.SimpleGcsInputChannelImpl$1.call(SimpleGcsInputChannelImpl.java:101)
at com.google.appengine.tools.cloudstorage.SimpleGcsInputChannelImpl$1.call(SimpleGcsInputChannelImpl.java:81)
at com.google.appengine.tools.cloudstorage.RetryHelper.doRetry(RetryHelper.java:75)
... 56 more
Caused by: java.lang.IllegalStateException: com.google.appengine.tools.cloudstorage.oauth.OauthRawGcsService$2#1d8c25d: got 46483 > wanted 19823
at com.google.common.base.Preconditions.checkState(Preconditions.java:177)
at com.google.appengine.tools.cloudstorage.oauth.OauthRawGcsService$2.wrap(OauthRawGcsService.java:418)
at com.google.appengine.tools.cloudstorage.oauth.OauthRawGcsService$2.wrap(OauthRawGcsService.java:398)
at com.google.appengine.api.utils.FutureWrapper.wrapAndCache(FutureWrapper.java:53)
at com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java:90)
at com.google.appengine.tools.cloudstorage.SimpleGcsInputChannelImpl$1.call(SimpleGcsInputChannelImpl.java:86)
... 58 more
What else should be added to read files with "gzip" compression to be able to read the content in app engine? ( curl cloud storage URL from client side works fine for both compressed and uncompressed file )
This is the code that works for uncompressed object:
byte[] blobContent = new byte[0];
try
{
GcsFileMetadata metaData = gcsService.getMetadata(fileName);
int fileSize = (int) metaData.getLength();
final int chunkSize = BlobstoreService.MAX_BLOB_FETCH_SIZE;
LOG.info("content encoding: " + metaData.getOptions().getContentEncoding()); // "gzip" here
LOG.info("input size " + fileSize); // the size is obviously the compressed size!
for (long offset = 0; offset < fileSize;)
{
if (offset != 0)
{
LOG.info("Handling extra size for " + filePath + " at " + offset);
}
final int size = Math.min(chunkSize, fileSize);
ByteBuffer result = ByteBuffer.allocate(size);
GcsInputChannel readChannel = gcsService.openReadChannel(fileName, offset);
try
{
readChannel.read(result); <<<< here the exception was thrown
}
finally
{
......
It is now compressed by:
GcsFilename filename = new GcsFilename(bucketName, filePath);
GcsFileOptions.Builder builder = new GcsFileOptions.Builder().mimeType(image_type);
builder = builder.contentEncoding("gzip");
GcsOutputChannel writeChannel = gcsService.createOrReplace(filename, builder.build());
ByteArrayOutputStream byteStream = new ByteArrayOutputStream(blob_content.length);
try
{
GZIPOutputStream zipStream = new GZIPOutputStream(byteStream);
try
{
zipStream.write(blob_content);
}
finally
{
zipStream.close();
}
}
finally
{
byteStream.close();
}
byte[] compressedData = byteStream.toByteArray();
writeChannel.write(ByteBuffer.wrap(compressedData));
the blob_content is compressed from 46483 bytes to 19823 bytes.
I think it is the google code's bug
https://code.google.com/p/appengine-gcs-client/source/browse/trunk/java/src/main/java/com/google/appengine/tools/cloudstorage/oauth/OauthRawGcsService.java, L418:
Preconditions.checkState(content.length <= want, "%s: got %s > wanted %s", this, content.length, want);
the HTTPResponse has decoded the blob, so the Precondition is wrong here.
If I good understand you have to set mineType:
GcsFileOptions options = new GcsFileOptions.Builder().mimeType("text/html")
Google Cloud Storage does not compress or decompress objects:
https://developers.google.com/storage/docs/reference-headers?csw=1#contentencoding
I hope that's what you want to do .
Looking at your code it seems like there is a mismatch between what is stored and what is read. The documentation specifies that compression is not done for you (https://developers.google.com/storage/docs/reference-headers?csw=1#contentencoding). You will need to do the actual compression manually.
Also if you look at the implementation of the class that throws the exception (https://code.google.com/p/appengine-gcs-client/source/browse/trunk/java/src/main/java/com/google/appengine/tools/cloudstorage/oauth/OauthRawGcsService.java?r=81&spec=svn134) you will notice that you get the original contents back but you're actually expecting compressed content. Check the method readObjectAsync in the above mentioned class.
It looks like the content persisted might not be gzipped or the content-length is not set properly. What you should do is verify length of the compressed stream just before writing it into the channel. You should also verify that the content length is set correctly when doing the http request. It would be useful to see the actual http request headers and make sure that content length header matches the actual content length in the http response.
Also it looks like contentEncoding could be set incorrectly. Try using:.contentEncoding("Content-Encoding: gzip") as used in this TCK test. Although still the best thing to do is inspect the HTTP request and response. You can use wireshark to do that easily.
Also you need to make sure that GCSOutputChannel is closed as that's when the file is finalized.
Hope this puts you on the right track. To gzip your contents you can use java GZIPInputStream.
I'm seeing the same issue, easily reproducable by uploading a file with "gsutil cp -Z", then trying to open it with the following
ByteArrayOutputStream output = new ByteArrayOutputStream();
try (GcsInputChannel readChannel = svc.openReadChannel(filename, 0)) {
try (InputStream input = Channels.newInputStream(readChannel))
{
IOUtils.copy(input, output);
}
}
This causes an exception like this:
java.lang.IllegalStateException:
....oauth.OauthRawGcsService$2#1883798: got 64303 > wanted 4096
at ....Preconditions.checkState(Preconditions.java:199)
at ....oauth.OauthRawGcsService$2.wrap(OauthRawGcsService.java:519)
at ....oauth.OauthRawGcsService$2.wrap(OauthRawGcsService.java:499)
The only work around I've found is to read the entire file into memory using readChannel.read:
int fileSize = 64303;
ByteBuffer result = ByteBuffer.allocate(fileSize);
try (GcsInputChannel readChannel = gcs.openReadChannel(new GcsFilename("mybucket", "mygzippedfile.xml"), 0)) {
readChannel.read(result);
}
Unfortunately, this only works if the size of the bytebuffer is greater or equal to the uncompressed size of the file, which is not possible to get via the api.
I've also posted my comment to an issue registered with google: https://code.google.com/p/googleappengine/issues/detail?id=10445
This is my function for reading compressed gzip files
public byte[] getUpdate(String fileName) throws IOException
{
GcsFilename fileNameObj = new GcsFilename(defaultBucketName, fileName);
try (GcsInputChannel readChannel = gcsService.openReadChannel(fileNameObj, 0))
{
maxSizeBuffer.clear();
readChannel.read(maxSizeBuffer);
}
byte[] result = maxSizeBuffer.array();
return result;
}
The core is that you cannot use the size of the saved file cause Google Storage will give it to you with the original size, so it checks the sizes you expected and the real size and these are differents:
Preconditions.checkState(content.length <= want, "%s: got %s > wanted
%s", this, content.length, want);
So i solved it allocating the biggest amount possible for these files using BlobstoreService.MAX_BLOB_FETCH_SIZE. Actually maxSizeBuffer is only allocated once outsize of the function
ByteBuffer maxSizeBuffer = ByteBuffer.allocate(BlobstoreService.MAX_BLOB_FETCH_SIZE);
And with maxSizeBuffer.clear(); all data is flushed again.
I am trying to write a program that will recognize an image on the screen, compare it against a resource library, and then calculate based on the result of the image source.
The first thing that I did was to create the capture screen function which looks like this:
private Bitmap Screenshot()
{
System.Drawing.Bitmap Table = new System.Drawing.Bitmap(88, 40, PixelFormat.Format32bppArgb);
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(RouletteTable);
g.CopyFromScreen(1047, 44, 0, 0, Screen.PrimaryScreen.Bounds.Size);
return Table;
}
Then, I analyze this picture. The first method I used was to create two for loops and analyze both the bitmaps pixel by pixel. The problem with this method was time, it took a long time to complete 37 times. I looked around and found the convert to bytes and the convert to hash methods. This is the result:
public enum CompareResult
{
ciCompareOk,
ciPixelMismatch,
ciSizeMismatch
};
public CompareResult Compare(Bitmap bmp1, Bitmap bmp2)
{
CompareResult cr = CompareResult.ciCompareOk;
//Test to see if we have the same size of image
if (bmp1.Size != bmp2.Size)
{
cr = CompareResult.ciSizeMismatch;
}
else
{
//Convert each image to a byte array
System.Drawing.ImageConverter ic = new System.Drawing.ImageConverter();
byte[] btImage1 = new byte[1];
btImage1 = (byte[])ic.ConvertTo(bmp1, btImage1.GetType());
byte[] btImage2 = new byte[1];
btImage2 = (byte[])ic.ConvertTo(bmp2, btImage2.GetType());
//Compute a hash for each image
SHA256Managed shaM = new SHA256Managed();
byte[] hash1 = shaM.ComputeHash(btImage1);
byte[] hash2 = shaM.ComputeHash(btImage2);
for (int i = 0; i < hash1.Length && i < hash2.Length&& cr == CompareResult.ciCompareOk; i++)
{
if (hash1[i] != hash2[i])
cr = CompareResult.ciPixelMismatch;
}
}
return cr;
}
After I analyze the two bitmaps in this function, I call it in my main form with the following:
Bitmap Table = Screenshot();
CompareResult success0 = Compare(Properties.Resources.Result0, Table);
if (success0 == CompareResult.ciCompareOk)
{ double result = 0; Num.Text = result.ToString(); goto end; }
The problem I am getting is that once this has all been accomplished, I am always getting a cr value of ciPixelMismatch. I cannot get the images to match, even though the images are identical.
To give you a bit more background on the two bitmaps, they are approximately 88 by 40 pixels, and located at 1047, 44 on the screen. I wrote a part of the program to automatically take a picture of that area so I did not have to worry about the wrong location or size being captured:
Table.Save("table.bmp");
After I took the picture and saved it, I moved it from the bin folder in the project directly to the resource folder and ran the program again. Despite all of this, the result is still ciPixelMismatch. I believe the problem lies within the format that the pictures are being saved as. I believe that despite them being the same image, they are being analyzed in different formats, maybe one of the pictures contains a bit more information than the other which is causing the mismatch. Can somebody please help me solve this problem? I am just beginning with my c# programming, I am 5 days into the learning process, and I am really at a loss for this.
Yours sincerely,
Samuel