I am working on implementing a SAMLSLO through HTTP-REDIRECT binding mechanism. Using deflate-inflate tools gives me a DataFormatException with incorrect header check.
I tried this as a stand-alone. Though I did not get DataFormatException here I observed the whole message is not being returned.
import java.io.UnsupportedEncodingException;
import java.util.logging.Level;
import java.util.zip.DataFormatException;
import java.util.zip.Deflater;
import java.util.zip.Inflater;
public class InflateDeflate {
public static void main(String[] args) {
String source = "This is the SAML String";
String outcome=null;
byte[] bytesource = null;
try {
bytesource = source.getBytes("UTF-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
int byteLength = bytesource.length;
Deflater compresser = new Deflater();
compresser.setInput(bytesource);
compresser.finish();
byte[] output = new byte[byteLength];
int compressedDataLength = compresser.deflate(output);
outcome = new String(output);
String trimmedoutcome = outcome.trim();
//String trimmedoutcome = outcome; // behaves the same way as trimmed;
// Now try to inflate it
Inflater decompresser = new Inflater();
decompresser.setInput(trimmedoutcome.getBytes());
byte[] result = new byte[4096];
int resultLength = 0;
try {
resultLength = decompresser.inflate(result);
} catch (DataFormatException e) {
e.printStackTrace();
}
decompresser.end();
System.out.println("result length ["+resultLength+"]");
String outputString = null;
outputString = new String(result, 0, resultLength);
String returndoc = outputString;
System.out.println(returndoc);
}
}
Surprisingly I get the result as [22] bytes, the original is [23] bytes and the 'g' is missing after inflating.
Am I doing something fundamentally wrong here?
Java's String is a CharacterSequence (a character is 2 bytes). Using new String(byte[]) may not correctly convert your byte[] to a String representation. At least you should specify a character encoding new String(byte[], "UTF-8") to prevent invalid character conversions.
Here's an example of compressing and decompressing:
import java.util.zip.Deflater;
import java.util.zip.InflaterInputStream;
...
byte[] sourceData; // bytes to compress (reuse byte[] for compressed data)
String filename; // where to write
{
// compress the data
Deflater deflater = new Deflater(Deflater.DEFAULT_COMPRESSION);
deflater.setInput(sourceData);
deflater.finish();
int compressedSize = deflater.deflate(data, 0, sourceData.length, Deflater.FULL_FLUSH);
// write the data
OutputStream stream = new FileOutputStream(filename);
stream.write(data, 0, compressedSize);
stream.close();
}
{
byte[] uncompressedData = new byte[1024]; // where to store the data
// read the data
InputStream stream = new InflaterInputStream(new FileInputStream(filename));
// read data - note: may not read fully (or evenly), read from stream until len==0
int len, offset = 0;
while ((len = stream.read(uncompressedData , offset, uncompressedData .length-offset))>0) {
offset += len;
}
stream.close();
}
Could you please point out where is the bug in my code?
I have a simple text file with the following data structure:
something1
something2
something3
...
It results a String[] where every element is the last element of the file. I can't find the mistake, but it goes wrong somewhere around the line.setLength(0);
Any ideas?
public String[] readText() throws IOException {
InputStream file = getClass().getResourceAsStream("/questions.txt");
DataInputStream in = new DataInputStream(file);
StringBuffer line = new StringBuffer();
Vector lines = new Vector();
int c;
try {
while( ( c = in.read()) != -1 ) {
if ((char)c == '\n') {
if (line.length() > 0) {
// debug
//System.out.println(line.toString());
lines.addElement(line);
line.setLength(0);
}
}
else{
line.append((char)c);
}
}
if(line.length() > 0){
lines.addElement(line);
line.setLength(0);
}
String[] splitArray = new String[lines.size()];
for (int i = 0; i < splitArray.length; i++) {
splitArray[i] = lines.elementAt(i).toString();
}
return splitArray;
} catch(Exception e) {
System.out.println(e.getMessage());
return null;
} finally {
in.close();
}
}
I see one obvious error - you're storing the same StringBuffer instance multiple times in the Vector, and you clear the same StringBuffer instance with setLength(0). I'm guesing you want to do something like this
StringBuffer s = new StringBuffer();
Vector v = new Vector();
...
String bufferContents = s.toString();
v.addElement(bufferContents);
s.setLength(0);
// now it's ok to reuse s
...
If your problem is to read the contents of the file in a String[], then you could actually use apache common's FileUtil class and read in an array list and then convert to an array.
List<String> fileContentsInList = FileUtils.readLines(new File("filename"));
String[] fileContentsInArray = new String[fileContentsInList.size()];
fileContentsInArray = (String[]) fileContentsInList.toArray(fileContentsInArray);
In the code that you have specified, rather than setting length to 0, you can reinitialize the StringBuffer.
I have a list of files, which need to be read, in chunks, into a byte[], which is then passed to a hashing function. The tricky part is this: if I reach the end of a file, I need to continue reading the next file untill I fill the buffer, like so:
read 16 bits as an example:
File 1: 00101010
File 2: 01101010111111111
would need to be read as 0010101001101010
The point is: these files can be as large as several gigabytes, and I don't want to completely load them into memory. Loading pieces into a buffer of, like, 30 MB would be perfectly fine.
I want to use threading, but would it be efficient to thread reading a file? I don't know if Disc I/O is such a large bottleneck that this would be worth it. Would the hashing be sped up sufficently if I only thread that part, and lock on the read of each chunk? It is important the hashes get saved in the correct order.
The second thing I need to do, is to generate the MD5sum from each file as well. Is there anyway to do this more efficiently than doing this as a separate step?
(This question has some overlap with Is there a built-in way to handle multiple files as one stream?, but I thought this differed enough)
I am really stumped what approach to take, as I am fairly new to C#, as well as to threading. I already tried the approaches listed below, but they do not suffice for me.
As I am new to C# I value every kind of input on any aspect of my code.
This piece of code was threaded, but does not 'append' the streams, and as such generates invalid hashes:
public void DoHashing()
{
ParallelOptions options = new ParallelOptions();
options.MaxDegreeOfParallelism = numThreads;
options.CancellationToken = cancelToken.Token;
Parallel.ForEach(files, options, (string f, ParallelLoopState loopState) =>
{
options.CancellationToken.ThrowIfCancellationRequested();
using (BufferedStream fileStream = new BufferedStream(File.OpenRead(f), bufferSize))
{
// Get the MD5sum first:
using (MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider())
{
md5.Initialize();
md5Sums[f] = BitConverter.ToString(md5.ComputeHash(fileStream)).Replace("-", "");
}
//setup for reading:
byte[] buffer = new byte[(int)pieceLength];
//I don't know if the buffer will f*ck up the filelenghth
long remaining = (new FileInfo(f)).Length;
int done = 0;
while (remaining > 0)
{
while (done < pieceLength)
{
options.CancellationToken.ThrowIfCancellationRequested();
//either try to read the piecelength, or the remaining length of the file.
int toRead = (int)Math.Min(pieceLength - done, remaining);
int read = fileStream.Read(buffer, done, toRead);
//if read == 0, EOF reached
if (read == 0)
{
remaining = 0;
break;
}
//offsets
done += read;
remaining -= read;
}
// Hash the piece
using (SHA1CryptoServiceProvider sha1 = new SHA1CryptoServiceProvider())
{
sha1.Initialize();
byte[] hash = sha1.ComputeHash(buffer);
hashes[f].AddRange(hash);
}
done = 0;
buffer = new byte[(int)pieceLength];
}
}
}
);
}
This other piece of code isn't threaded (and doesn't calculate MD5):
void Hash()
{
//examples, these got handled by other methods
List<string> files = new List<string>();
files.Add("a.txt");
files.Add("b.blob");
//....
long totalFileLength;
int pieceLength = Math.Pow(2,20);
foreach (string file in files)
{
totalFileLength += (new FileInfo(file)).Length;
}
//Reading the file:
long remaining = totalFileLength;
byte[] buffer = new byte[Math.min(remaining, pieceSize)];
int index = 0;
FileStream fin = File.OpenRead(files[index]);
int done = 0;
int offset = 0;
while (remaining > 0)
{
while (done < pieceLength)
{
int toRead = (int)Math.Min(pieceLength - offset, remaining);
int read = fin.Read(buffer, done, toRead);
//if read == 0, EOF reached
if (read == 0)
{
index++;
//if last file:
if (index > files.Count)
{
remaining = 0;
break;
}
//get ready for next round:
offset = 0;
fin.OpenRead(files[index]);
}
done += read;
offset += read;
remaining -= read;
}
//Doing the piece hash:
HashPiece(buffer);
//reset for next piece:
done = 0;
byte[] buffer = new byte[Math.min(remaining, pieceSize)];
}
}
void HashPiece(byte[] piece)
{
using (SHA1CryptoServiceProvider sha1 = new SHA1CryptoServiceProvider())
{
sha1.Initialize();
//hashes is a List
hashes.Add(sha1.ComputeHash(piece));
}
}
Thank you very much for your time and effort.
I'm not looking for completely coded solutions, any pointer and idea where to go with this would be excellent.
Questions & remarks to yodaj007's answer:
Why if (currentChunk.Length >= Constants.CHUNK_SIZE_IN_BYTES)? Why not ==? If the chunk is larger than the chunk size, my SHA1 hash gets a different value.
currentChunk.Sources.Add(new ChunkSource()
{
Filename = fi.FullName,
StartPosition = 0,
Length = (int)Math.Min(fi.Length, (long)needed)
});
Is a really interesting idea. Postpone reading untill you need it. Nice!
chunks.Add(currentChunk = new Chunk());
Why do this in the if (currentChunk != null) block and in the for (int i = 0; i < (fi.Length - offset) / Constants.CHUNK_SIZE_IN_BYTES; i++) block? Isn't the first a bit redundant?
Here is my complete answer. I tested it on one of my anime folders. It processes 14 files totaling 3.64GiB in roughly 16 seconds. In my opinion, using any sort of parallelism is more trouble than it is worth here. You're being limited by disc I/O, so multithreading will only get you so far. My solution can be easily parallelized though.
It starts by reading "chunk" source information: source file, offset, and length. All of this is gathered very quickly. From here, you can process the "chunks" using threading however you wish. Code follows:
public static class Constants
{
public const int CHUNK_SIZE_IN_BYTES = 32 * 1024 * 1024; // 32MiB
}
public class ChunkSource
{
public string Filename { get; set; }
public int StartPosition { get; set; }
public int Length { get; set; }
}
public class Chunk
{
private List<ChunkSource> _sources = new List<ChunkSource>();
public IList<ChunkSource> Sources { get { return _sources; } }
public byte[] Hash { get; set; }
public int Length
{
get { return Sources.Select(s => s.Length).Sum(); }
}
}
static class Program
{
static void Main()
{
DirectoryInfo di = new DirectoryInfo(#"C:\Stuff\Anime\Shikabane Hime Aka");
string[] filenames = di.GetFiles().Select(fi=> fi.FullName).OrderBy(n => n).ToArray();
var chunks = ChunkFiles(filenames);
ComputeHashes(chunks);
}
private static List<Chunk> ChunkFiles(string[] filenames)
{
List<Chunk> chunks = new List<Chunk>();
Chunk currentChunk = null;
int offset = 0;
foreach (string filename in filenames)
{
FileInfo fi = new FileInfo(filename);
if (!fi.Exists)
throw new FileNotFoundException(filename);
Debug.WriteLine(String.Format("File: {0}", filename));
//
// First, start off by either starting a new chunk or
// by finishing a leftover chunk from a previous file.
//
if (currentChunk != null)
{
//
// We get here if the previous file had leftover bytes that left us with an incomplete chunk
//
int needed = Constants.CHUNK_SIZE_IN_BYTES - currentChunk.Length;
if (needed == 0)
throw new InvalidOperationException("Something went wonky, shouldn't be here");
offset = needed;
currentChunk.Sources.Add(new ChunkSource()
{
Filename = fi.FullName,
StartPosition = 0,
Length = (int)Math.Min(fi.Length, (long)needed)
});
if (currentChunk.Length >= Constants.CHUNK_SIZE_IN_BYTES)
{
chunks.Add(currentChunk = new Chunk());
}
}
else
{
offset = 0;
}
//
// Note: Using integer division here
//
for (int i = 0; i < (fi.Length - offset) / Constants.CHUNK_SIZE_IN_BYTES; i++)
{
chunks.Add(currentChunk = new Chunk());
currentChunk.Sources.Add(new ChunkSource()
{
Filename = fi.FullName,
StartPosition = i * Constants.CHUNK_SIZE_IN_BYTES + offset,
Length = Constants.CHUNK_SIZE_IN_BYTES
});
Debug.WriteLine(String.Format("Chunk source created: Offset = {0,10}, Length = {1,10}", currentChunk.Sources[0].StartPosition, currentChunk.Sources[0].Length));
}
int leftover = (int)(fi.Length - offset) % Constants.CHUNK_SIZE_IN_BYTES;
if (leftover > 0)
{
chunks.Add(currentChunk = new Chunk());
currentChunk.Sources.Add(new ChunkSource()
{
Filename = fi.FullName,
StartPosition = (int)(fi.Length - leftover),
Length = leftover
});
}
else
{
currentChunk = null;
}
}
return chunks;
}
private static void ComputeHashes(IList<Chunk> chunks)
{
if (chunks == null || chunks.Count == 0)
return;
Dictionary<string, MemoryMappedFile> files = new Dictionary<string, MemoryMappedFile>();
foreach (var chunk in chunks)
{
MemoryMappedFile mms = null;
byte[] buffer = new byte[Constants.CHUNK_SIZE_IN_BYTES];
Stopwatch sw = Stopwatch.StartNew();
foreach (var source in chunk.Sources)
{
lock (files)
{
if (!files.TryGetValue(source.Filename, out mms))
{
Debug.WriteLine(String.Format("Opening {0}", source.Filename));
files.Add(source.Filename, mms = MemoryMappedFile.CreateFromFile(source.Filename, FileMode.Open));
}
}
var view = mms.CreateViewStream(source.StartPosition, source.Length);
view.Read(buffer, 0, source.Length);
}
Debug.WriteLine("Done reading sources in {0}ms", sw.Elapsed.TotalMilliseconds);
sw.Restart();
MD5 md5 = MD5.Create();
chunk.Hash = md5.ComputeHash(buffer);
sw.Stop();
Debug.WriteLine(String.Format("Computed hash: {0} in {1}ms", String.Join("-", chunk.Hash.Select(h=> h.ToString("X2")).ToArray()), sw.Elapsed.TotalMilliseconds));
}
foreach (var x in files.Values)
{
x.Dispose();
}
}
}
I don't guarantee everything is spotlessly free of bugs. But I did have fun working on it. Look at the output window in Visual Studio for the debug information. It looks like this:
File: C:\Stuff\Anime\Shikabane Hime Aka\Episode 02.mkv
Chunk source created: Offset = 26966010, Length = 33554432
Chunk source created: Offset = 60520442, Length = 33554432
Chunk source created: Offset = 94074874, Length = 33554432
Chunk source created: Offset = 127629306, Length = 33554432
Chunk source created: Offset = 161183738, Length = 33554432
Chunk source created: Offset = 194738170, Length = 33554432
Chunk source created: Offset = 228292602, Length = 33554432
...
Opening C:\Stuff\Anime\Shikabane Hime Aka\Episode 02.mkv
Done reading sources in 42.9362ms
The thread '' (0xc10) has exited with code 0 (0x0).
Computed hash: 3C-81-A5-2C-90-02-24-23-42-5B-19-A2-15-56-AB-3F in 94.2481ms
Done reading sources in 0.0053ms
Computed hash: 58-F0-6D-D5-88-D8-FF-B3-BE-B4-6A-DA-63-09-43-6B in 98.9263ms
Done reading sources in 29.4805ms
Computed hash: F7-19-8D-A8-FE-9C-07-6E-DB-D5-74-A6-E1-E7-A6-26 in 85.0061ms
Done reading sources in 28.4971ms
Computed hash: 49-F2-CB-75-89-9A-BC-FA-94-A7-DF-E0-DB-02-8A-99 in 84.2799ms
Done reading sources in 31.106ms
Computed hash: 29-7B-18-BD-ED-E9-0C-68-4B-47-C6-5F-D0-16-8A-44 in 84.1444ms
Done reading sources in 31.2204ms
Computed hash: F8-91-F1-90-CF-9C-37-4E-82-68-C2-44-0D-A7-6E-F8 in 84.2592ms
Done reading sources in 31.0031ms
Computed hash: 65-97-ED-95-07-31-BF-C8-3A-BA-2B-DA-03-37-FD-00 in 95.331ms
Done reading sources in 33.0072ms
Computed hash: 9B-F2-83-E6-A8-DF-FD-8D-6C-5C-9E-F4-20-0A-38-4B in 85.9561ms
Done reading sources in 31.6232ms
Computed hash: B6-7C-6B-95-69-BC-9C-B2-1A-07-B3-13-28-A8-10-BC in 84.1866ms
Here is the parallel version. It's basically the same really. Using parallelism = 3 cut the processing time down to 9 seconds.
private static void ComputeHashes(IList<Chunk> chunks)
{
if (chunks == null || chunks.Count == 0)
return;
Dictionary<string, MemoryMappedFile> files = new Dictionary<string, MemoryMappedFile>();
Parallel.ForEach(chunks, new ParallelOptions() { MaxDegreeOfParallelism = 2 }, (chunk, state, index) =>
{
MemoryMappedFile mms = null;
byte[] buffer = new byte[Constants.CHUNK_SIZE_IN_BYTES];
Stopwatch sw = Stopwatch.StartNew();
foreach (var source in chunk.Sources)
{
lock (files)
{
if (!files.TryGetValue(source.Filename, out mms))
{
Debug.WriteLine(String.Format("Opening {0}", source.Filename));
files.Add(source.Filename, mms = MemoryMappedFile.CreateFromFile(source.Filename, FileMode.Open));
}
}
var view = mms.CreateViewStream(source.StartPosition, source.Length);
view.Read(buffer, 0, source.Length);
}
Debug.WriteLine("Done reading sources in {0}ms", sw.Elapsed.TotalMilliseconds);
sw.Restart();
MD5 md5 = MD5.Create();
chunk.Hash = md5.ComputeHash(buffer);
sw.Stop();
Debug.WriteLine(String.Format("Computed hash: {0} in {1}ms", String.Join("-", chunk.Hash.Select(h => h.ToString("X2")).ToArray()), sw.Elapsed.TotalMilliseconds));
});
foreach (var x in files.Values)
{
x.Dispose();
}
}
EDIT
I found a bug, or what I think is a bug. Need to set the read offset to 0 if we're starting a new file.
EDIT 2 based on feedback
This processes the hashes in a separate thread. It's necessary to throttle the I/O. I was running into OutOfMemoryException without doing so. It doesn't really perform that much better, though. Beyond this... I'm not sure how it can be improved any further. Perhaps by reusing the buffers, maybe.
public class QueueItem
{
public Chunk Chunk { get; set; }
public byte[] buffer { get; set; }
}
private static void ComputeHashes(IList<Chunk> chunks)
{
if (chunks == null || chunks.Count == 0)
return;
Dictionary<string, MemoryMappedFile> files = new Dictionary<string, MemoryMappedFile>();
foreach (var filename in chunks.SelectMany(c => c.Sources).Select(c => c.Filename).Distinct())
{
files.Add(filename, MemoryMappedFile.CreateFromFile(filename, FileMode.Open));
}
AutoResetEvent monitor = new AutoResetEvent(false);
ConcurrentQueue<QueueItem> hashQueue = new ConcurrentQueue<QueueItem>();
CancellationToken token = new CancellationToken();
Task.Factory.StartNew(() =>
{
int processCount = 0;
QueueItem item = null;
while (!token.IsCancellationRequested)
{
if (hashQueue.TryDequeue(out item))
{
MD5 md5 = MD5.Create();
item.Chunk.Hash = md5.ComputeHash(item.buffer);
if (processCount++ > 1000)
{
processCount = 0;
monitor.Set();
}
}
}
}, token);
foreach (var chunk in chunks)
{
if (hashQueue.Count > 10000)
{
monitor.WaitOne();
}
QueueItem item = new QueueItem()
{
buffer = new byte[Constants.CHUNK_SIZE_IN_BYTES],
Chunk = chunk
};
Stopwatch sw = Stopwatch.StartNew();
foreach (var source in chunk.Sources)
{
MemoryMappedFile mms = files[source.Filename];
var view = mms.CreateViewStream(source.StartPosition, source.Length);
view.Read(item.buffer, 0, source.Length);
}
sw.Restart();
sw.Stop();
hashQueue.Enqueue(item);
}
foreach (var x in files.Values)
{
x.Dispose();
}
}
I'm new to C# too, but I think what your are looking for is System.IO.MemoryMappedFiles namespace since C# 4.0
Using this API functions the operating system itself takes care how to manage the current file region in memory.
In stead of copy&paste code here, continue reading this article: http://www.developer.com/net/article.php/3828586/Using-Memory-Mapped-Files-in-NET-40.htm
Regarding the MD5 use the System.Security.Cryptography.MD5CryptoServiceProvider class. Maybe it's faster.
In your case where you have to go over the "boundaries" of one file, do it. Let the operating system handle how the memory mapped files are represented in memory. Work as you would do with "small" sized buffers.
In .Net 4 you now have System.IO.MemoryMappedFiles
You can create a ViewAccessor of a particular chuck size to match your hash function, and then just keep filling your hash function buffer from the current ViewAccessor, when you run out of file, start chunking the next file using the current hash chuck offset as your ViewAccessor offset
JavaME is quite sparse on features. Please list your favourite utility functions for making using it more like using proper Java, one per answer. Try to make your answers specific to Java ME.
Small Logging Framework
MicroLog
http://microlog.sourceforge.net/site/
Splitting a string
static public String[] split(String str, char c)
{
int l=str.length();
int count = 0;
for(int i = 0;i < l;i++)
{
if (str.charAt(i) == c)
{
count ++;
}
}
int first = 0;
int last = 0;
int segment=0;
String[] array = new String[count + 1];
for(int i=0;i<l;i++)
{
if (str.charAt(i) == c)
{
last = i;
array[segment++] = str.substring(first,last);
first = last;
}
if(i==l-1){
array[segment++] = str.substring(first,l);
}
}
return array;
}
Read a line from a reader. See also this question.
public class LineReader{
private Reader in;
private int bucket=-1;
public LineReader(Reader in){
this.in=in;
}
public boolean hasLine() throws IOException{
if(bucket!=-1)return true;
bucket=in.read();
return bucket!=-1;
}
//Read a line, removing any /r and /n. Buffers the string
public String readLine() throws IOException{
int tmp;
StringBuffer out=new StringBuffer();
//Read in data
while(true){
//Check the bucket first. If empty read from the input stream
if(bucket!=-1){
tmp=bucket;
bucket=-1;
}else{
tmp=in.read();
if(tmp==-1)break;
}
//If new line, then discard it. If we get a \r, we need to look ahead so can use bucket
if(tmp=='\r'){
int nextChar=in.read();
if(tmp!='\n')bucket=nextChar;//Ignores \r\n, but not \r\r
break;
}else if(tmp=='\n'){
break;
}else{
//Otherwise just append the character
out.append((char) tmp);
}
}
return out.toString();
}
}
Does anyone know of a good resource on the Audible Audio (.aa) file spec?
I'm trying to write a program that can use them, if no one knows of a resource, any tips on reverse engineering the spec my self? I opened it up in a Hex editor and poked around, looks like an MP3 but with a ton more header info.
This site provides some more info in regards to where certain chunks of data reside within the .aa file.
http://wiki.multimedia.cx/index.php?title=Audible_Audio
I have done some research into the Audible header to create a player for my car radio/computer. Basically there is a block of 3700 characters at the beginning of the file that encompasses a number of fields of interest, such as Title, Author, Narrator, etc. I have some limited parsing code in C# to display some of the basic info from the .aa file. as follows:
private void ParseFields(string fileName)
{
string aaHeader;
string tryDate;
if (fileName == "") return;
using (StreamReader sr = new StreamReader(fileName))
{
char[] buff = new char[3700];
sr.Read(buff, 0, buff.Length);
aaHeader = new string(buff);
}
try
{
_author = GetParsedItem(aaHeader, "author");
}
catch
{
_author = "?";
}
try
{
_title = GetParsedItem(aaHeader, "short_title");
}
catch
{
_title = "???";
}
try
{
_narrator = GetParsedItem(aaHeader, "narrator");
}
catch
{
_narrator = "?";
}
try
{
_description = GetParsedItem(aaHeader, "description");
}
catch
{
_description = "???";
}
try
{
_longDescription = GetParsedItem(aaHeader, "long_description");
}
catch
{
_longDescription = "";
}
try
{
tryDate = GetParsedItem(aaHeader, "pubdate");
if (tryDate != "")
_pubDate = Convert.ToDateTime(GetParsedItem(aaHeader, "pubdate"));
else
_pubDate = DateTime.Today;
}
catch
{
_pubDate = DateTime.Today;
}
}
private string GetParsedItem(string buffer, string fieldName)
{
if (buffer.Contains(fieldName))
{
int pos = buffer.IndexOf(fieldName);
pos += fieldName.Length;
int posEnd = buffer.IndexOf('\0',pos);
//if the value for the field is empty, skip it and look for another
if (pos == posEnd)
{
pos = buffer.IndexOf(fieldName, posEnd);
pos += fieldName.Length;
posEnd = buffer.IndexOf('\0', pos);
}
return buffer.Substring(pos, posEnd - pos);
}
else
return "(not found - " + fieldName + ")";
}
I think, there is no spec. Have a look at Wikipedia/Audible.com:
quote:
[...]
Audible introduced one of the first digital audio players in 1997.
The following year it published a Web site from which audio files in its
proprietary .aa format could be downloaded. Audible holds a number of patents
in this area.
[...]
summary: proprietary/patents