package com.jmatio.io; import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.io.ObjectInputStream; import java.io.RandomAccessFile; import java.lang.ref.WeakReference; import java.lang.reflect.Method; import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.nio.MappedByteBuffer; import java.nio.channels.FileChannel; import java.security.AccessController; import java.security.PrivilegedAction; import java.util.ArrayList; import java.util.LinkedHashMap; import java.util.Map; import java.util.zip.InflaterInputStream; import com.jmatio.common.MatDataTypes; import com.jmatio.io.stream.BufferedOutputStream; import com.jmatio.io.stream.ByteBufferInputStream; import com.jmatio.io.stream.ByteBufferedOutputStream; import com.jmatio.io.stream.FileBufferedOutputStream; import com.jmatio.io.stream.MatFileInputStream; import com.jmatio.types.ByteStorageSupport; import com.jmatio.types.MLArray; import com.jmatio.types.MLCell; import com.jmatio.types.MLChar; import com.jmatio.types.MLDouble; import com.jmatio.types.MLEmptyArray; import com.jmatio.types.MLInt16; import com.jmatio.types.MLInt32; import com.jmatio.types.MLInt64; import com.jmatio.types.MLInt8; import com.jmatio.types.MLJavaObject; import com.jmatio.types.MLNumericArray; import com.jmatio.types.MLObject; import com.jmatio.types.MLSingle; import com.jmatio.types.MLSparse; import com.jmatio.types.MLStructure; import com.jmatio.types.MLUInt32; import com.jmatio.types.MLUInt64; import com.jmatio.types.MLUInt8; /** * MAT-file reader. Reads MAT-file into MLArray objects. * * Usage: *

 * //read in the file
 * MatFileReader mfr = new MatFileReader( "mat_file.mat" );
 * 
 * //get array of a name "my_array" from file
 * MLArray mlArrayRetrived = mfr.getMLArray( "my_array" );
 * 
 * //or get the collection of all arrays that were stored in the file
 * Map content = mfr.getContent();
 * 
* * @see com.jmatio.io.MatFileFilter * @author Wojciech Gradkowski (wgradkowski@gmail.com) */ /** * @author Wojciech Gradkowski (wgradkowski@gmail.com) * */ public class MatFileReader { public static final int MEMORY_MAPPED_FILE = 1; public static final int DIRECT_BYTE_BUFFER = 2; public static final int HEAP_BYTE_BUFFER = 4; /** * MAT-file header */ private MatFileHeader matFileHeader; /** * Container for red MLArrays */ private Map data; /** * Tells how bytes are organized in the buffer. */ private ByteOrder byteOrder; /** * Array name filter */ private MatFileFilter filter; /** * Creates instance of MatFileReader and reads MAT-file * from location given as fileName. * * This method reads MAT-file without filtering. * * @param fileName the MAT-file path String * @throws IOException when error occurred while processing the file. */ public MatFileReader(String fileName) throws FileNotFoundException, IOException { this ( new File(fileName), new MatFileFilter() ); } /** * Creates instance of MatFileReader and reads MAT-file * from location given as fileName. * * Results are filtered by MatFileFilter. Arrays that do not meet * filter match condition will not be available in results. * * @param fileName the MAT-file path String * @param MatFileFilter array name filter. * @throws IOException when error occurred while processing the file. */ public MatFileReader(String fileName, MatFileFilter filter ) throws IOException { this( new File(fileName), filter ); } /** * Creates instance of MatFileReader and reads MAT-file * from file. * * This method reads MAT-file without filtering. * * @param file the MAT-file * @throws IOException when error occurred while processing the file. */ public MatFileReader(File file) throws IOException { this ( file, new MatFileFilter() ); } /** * Creates instance of MatFileReader and reads MAT-file from * file. *

* Results are filtered by MatFileFilter. Arrays that do not * meet filter match condition will not be available in results. *

* Note: this method reads file using the memory mapped file policy, see * notes to {@link #read(File, MatFileFilter, com.jmatio.io.MatFileReader.MallocPolicy)} * * @param file * the MAT-file * @param MatFileFilter * array name filter. * @throws IOException * when error occurred while processing the file. */ public MatFileReader(File file, MatFileFilter filter) throws IOException { this(); read(file, filter, MEMORY_MAPPED_FILE); } public MatFileReader() { filter = new MatFileFilter(); data = new LinkedHashMap(); } /** * Reads the content of a MAT-file and returns the mapped content. *

* This method calls * read(file, new MatFileFilter(), MallocPolicy.MEMORY_MAPPED_FILE). * * @param file * a valid MAT-file file to be read * @return the same as {@link #getContent()} * @throws IOException * if error occurs during file processing */ public synchronized Map read(File file) throws IOException { return read(file, new MatFileFilter(), MEMORY_MAPPED_FILE); } /** * Reads the content of a MAT-file and returns the mapped content. *

* This method calls * read(file, new MatFileFilter(), policy). * * @param file * a valid MAT-file file to be read * @param policy * the file memory allocation policy * @return the same as {@link #getContent()} * @throws IOException * if error occurs during file processing */ public synchronized Map read(File file, int policy) throws IOException { return read(file, new MatFileFilter(), policy); } /** * Reads the content of a MAT-file and returns the mapped content. *

* Because of java bug #4724038 * which disables releasing the memory mapped resource, additional different * allocation modes are available. *

* Note: memory mapped file will try to invoke a nasty code to relase * it's resources * * @param file * a valid MAT-file file to be read * @param filter * the array filter applied during reading * @param policy * the file memory allocation policy * @return the same as {@link #getContent()} * @see MatFileFilter * @throws IOException * if error occurs during file processing */ private static final int DIRECT_BUFFER_LIMIT = 1 << 25; public synchronized Map read(File file, MatFileFilter filter, int policy) throws IOException { this.filter = filter; //clear the results for ( String key : data.keySet() ) { data.remove(key); } FileChannel roChannel = null; RandomAccessFile raFile = null; ByteBuffer buf = null; WeakReference bufferWeakRef = null; try { //Create a read-only memory-mapped file raFile = new RandomAccessFile(file, "r"); roChannel = raFile.getChannel(); // until java bug #4715154 is fixed I am not using memory mapped files // The bug disables re-opening the memory mapped files for writing // or deleting until the VM stops working. In real life I need to open // and update files switch ( policy ) { case DIRECT_BYTE_BUFFER: buf = ByteBuffer.allocateDirect( (int)roChannel.size() ); roChannel.read(buf, 0); buf.rewind(); break; case HEAP_BYTE_BUFFER: int filesize = (int)roChannel.size(); System.gc(); buf = ByteBuffer.allocate( filesize ); // The following two methods couldn't be used (at least under MS Windows) // since they are implemented in a suboptimal way. Each of them // allocates its own _direct_ buffer of exactly the same size, // the buffer passed as parameter has, reads data into it and // only afterwards moves data into the buffer passed as parameter. // roChannel.read(buf, 0); // ends up in outOfMemory // raFile.readFully(buf.array()); // ends up in outOfMemory int numberOfBlocks = filesize / DIRECT_BUFFER_LIMIT + ((filesize % DIRECT_BUFFER_LIMIT) > 0 ? 1 : 0); if (numberOfBlocks > 1) { ByteBuffer tempByteBuffer = ByteBuffer.allocateDirect(DIRECT_BUFFER_LIMIT); for (int block=0; block((MappedByteBuffer)buf); break; default: throw new IllegalArgumentException("Unknown file allocation policy"); } //read in file header readHeader(buf); while ( buf.remaining() > 0 ) { readData( buf ); } return getContent(); } catch ( IOException e ) { throw e; } finally { if ( roChannel != null ) { roChannel.close(); } if ( raFile != null ) { raFile.close(); } // if ( buf != null && bufferWeakRef != null && policy == MEMORY_MAPPED_FILE ) // { // try // { // clean(buf); // } // catch ( Exception e ) // { // int GC_TIMEOUT_MS = 1000; // buf = null; // long start = System.currentTimeMillis(); // while (bufferWeakRef.get() != null) // { // if (System.currentTimeMillis() - start > GC_TIMEOUT_MS) // { // break; //a hell cannot be unmapped - hopefully GC will // //do it's job later // } // System.gc(); // Thread.yield(); // } // } // } } } // /** // * Workaround taken from bug #4724038 // * to release the memory mapped byte buffer. // *

// * Little quote from SUN: This is highly inadvisable, to put it mildly. // * It is exceedingly dangerous to forcibly unmap a mapped byte buffer that's // * visible to Java code. Doing so risks both the security and stability of // * the system // *

// * Since the memory byte buffer used to map the file is not exposed to the // * outside world, maybe it's save to use it without being cursed by the SUN. // * Since there is no other solution this will do (don't trust voodoo GC // * invocation) // * // * @param buffer // * the buffer to be unmapped // * @throws Exception // * all kind of evil stuff // */ // private void clean(final Object buffer) throws Exception // { // AccessController.doPrivileged(new PrivilegedAction() // { // public Object run() // { // try // { // Method getCleanerMethod = buffer.getClass().getMethod( // "cleaner", new Class[0]); // getCleanerMethod.setAccessible(true); // sun.misc.Cleaner cleaner = (sun.misc.Cleaner) getCleanerMethod // .invoke(buffer, new Object[0]); // cleaner.clean(); // } // catch (Exception e) // { // e.printStackTrace(); // } // return null; // } // }); // } /** * Gets MAT-file header * * @return - a MatFileHeader object */ public MatFileHeader getMatFileHeader() { return matFileHeader; } /** * Returns list of MLArray objects that were inside MAT-file * * @return - a ArrayList * @deprecated use getContent which returns a Map to provide * easier access to MLArrays contained in MAT-file */ public ArrayList getData() { return new ArrayList( data.values() ); } /** * Returns the value to which the red file maps the specified array name. * * Returns null if the file contains no content for this name. * * @param - array name * @return - the MLArray to which this file maps the specified name, * or null if the file contains no content for this name. */ public MLArray getMLArray( String name ) { return data.get( name ); } /** * Returns a map of MLArray objects that were inside MAT-file. * * MLArrays are mapped with MLArrays' names * * @return - a Map of MLArrays mapped with their names. */ public Map getContent() { return data; } /** * Reads data form byte buffer. Searches for either * miCOMPRESSED data or miMATRIX data. * * Compressed data are inflated and the product is recursively passed back * to this same method. * * Modifies buf position. * * @param buf - * input byte buffer * @throws IOException when error occurs while reading the buffer. */ private void readData( ByteBuffer buf ) throws IOException { //read data ISMatTag tag = new ISMatTag(buf); switch ( tag.type ) { case MatDataTypes.miCOMPRESSED: long numOfBytes = tag.size; //inflate and recur if ( buf.remaining() < numOfBytes ) { throw new MatlabIOException("Compressed buffer length miscalculated!"); } //instead of standard Inlater class instance I use an inflater input //stream... gives a great boost to the performance InflaterInputStream iis = new InflaterInputStream(new ByteBufferInputStream(buf, numOfBytes)); //process data decompression byte[] result = new byte[1024]; // use direct buffer allocation // BufferedOutputStream dos = new FileBufferedOutputStream(); BufferedOutputStream dos = new ByteBufferedOutputStream( tag.size, false ); int i; try { do { i = iis.read(result, 0, result.length); int len = Math.max(0, i); dos.write(result, 0, len); } while ( i > 0 ); } catch ( IOException e ) { throw new MatlabIOException("Could not decompress data: " + e ); } finally { iis.close(); dos.flush(); } //create a ByteBuffer from the deflated data ByteBuffer out = dos.buffer(); out.rewind(); //with proper byte ordering out.order( byteOrder ); try { readData( out ); } catch ( IOException e ) { throw e; } finally { dos.close(); } break; case MatDataTypes.miMATRIX: //read in the matrix int pos = buf.position(); MLArray element = readMatrix( buf, true ); if ( element != null && !data.containsKey( element.getName() ) ) { data.put( element.getName(), element ); } else { int red = buf.position() - pos; int toread = tag.size - red; buf.position( buf.position() + toread ); } int red = buf.position() - pos; int toread = tag.size - red; if ( toread != 0 ) { throw new MatlabIOException("Matrix was not red fully! " + toread + " remaining in the buffer."); } break; default: throw new MatlabIOException("Incorrect data tag: " + tag); } } /** * Reads miMATRIX from from input stream. * * If reading was not finished (which is normal for filtered results) * returns null. * * Modifies buf position to the position when reading * finished. * * Uses recursive processing for some ML**** data types. * * @param buf - * input byte buffer * @param isRoot - * when true informs that if this is a top level * matrix * @return - MLArray or null if matrix does * not match filter * @throws IOException when error occurs while reading the buffer. */ private MLArray readMatrix(ByteBuffer buf, boolean isRoot ) throws IOException { //result MLArray mlArray; ISMatTag tag; //read flags int[] flags = readFlags(buf); int attributes = ( flags.length != 0 ) ? flags[0] : 0; int nzmax = ( flags.length != 0 ) ? flags[1] : 0; int type = attributes & 0xff; //read Array dimension int[] dims = readDimension(buf); //read array Name String name = readName(buf); //if this array is filtered out return immediately if ( isRoot && !filter.matches(name) ) { return null; } //read data >> consider changing it to stategy pattern switch ( type ) { case MLArray.mxSTRUCT_CLASS: MLStructure struct = new MLStructure(name, dims, type, attributes); //field name lenght - this subelement always uses the compressed data element format tag = new ISMatTag(buf); int maxlen = buf.getInt(); //maximum field length ////// read fields data as Int8 tag = new ISMatTag(buf); //calculate number of fields int numOfFields = tag.size/maxlen; String[] fieldNames = new String[numOfFields]; for ( int i = 0; i < numOfFields; i++ ) { byte[] names = new byte[maxlen]; buf.get(names); fieldNames[i] = zeroEndByteArrayToString(names); } buf.position( buf.position() + tag.padding ); //read fields for ( int index = 0; index < struct.getM()*struct.getN(); index++ ) { for ( int i = 0; i < numOfFields; i++ ) { //read matrix recursively tag = new ISMatTag(buf); if ( tag.size > 0 ) { MLArray fieldValue = readMatrix( buf, false); struct.setField(fieldNames[i], fieldValue, index); } else { struct.setField(fieldNames[i], new MLEmptyArray(), index); } } } mlArray = struct; break; case MLArray.mxCELL_CLASS: MLCell cell = new MLCell(name, dims, type, attributes); for ( int i = 0; i < cell.getM()*cell.getN(); i++ ) { tag = new ISMatTag(buf); if ( tag.size > 0 ) { //read matrix recursively MLArray cellmatrix = readMatrix( buf, false); cell.set(cellmatrix, i); } else { cell.set(new MLEmptyArray(), i); } } mlArray = cell; break; case MLArray.mxDOUBLE_CLASS: mlArray = new MLDouble(name, dims, type, attributes); //read real tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getRealByteBuffer(), (MLNumericArray) mlArray ); //read complex if ( mlArray.isComplex() ) { tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getImaginaryByteBuffer(), (MLNumericArray) mlArray ); } break; case MLArray.mxSINGLE_CLASS: mlArray = new MLSingle(name, dims, type, attributes); //read real tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getRealByteBuffer(), (MLNumericArray) mlArray ); //read complex if ( mlArray.isComplex() ) { tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getImaginaryByteBuffer(), (MLNumericArray) mlArray ); } break; case MLArray.mxUINT8_CLASS: mlArray = new MLUInt8(name, dims, type, attributes); //read real tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getRealByteBuffer(), (MLNumericArray) mlArray ); //read complex if ( mlArray.isComplex() ) { tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getImaginaryByteBuffer(), (MLNumericArray) mlArray ); } break; case MLArray.mxINT8_CLASS: mlArray = new MLInt8(name, dims, type, attributes); //read real tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getRealByteBuffer(), (MLNumericArray) mlArray ); //read complex if ( mlArray.isComplex() ) { tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getImaginaryByteBuffer(), (MLNumericArray) mlArray ); } break; case MLArray.mxINT16_CLASS: mlArray = new MLInt16(name, dims, type, attributes); //read real tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getRealByteBuffer(), (MLNumericArray) mlArray ); //read complex if ( mlArray.isComplex() ) { tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getImaginaryByteBuffer(), (MLNumericArray) mlArray ); } break; case MLArray.mxINT32_CLASS: mlArray = new MLInt32(name, dims, type, attributes); //read real tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getRealByteBuffer(), (MLNumericArray) mlArray ); //read complex if ( mlArray.isComplex() ) { tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getImaginaryByteBuffer(), (MLNumericArray) mlArray ); } break; case MLArray.mxUINT32_CLASS: mlArray = new MLUInt32(name, dims, type, attributes); //read real tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getRealByteBuffer(), (MLNumericArray) mlArray ); //read complex if ( mlArray.isComplex() ) { tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getImaginaryByteBuffer(), (MLNumericArray) mlArray ); } break; case MLArray.mxINT64_CLASS: mlArray = new MLInt64(name, dims, type, attributes); //read real tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getRealByteBuffer(), (MLNumericArray) mlArray ); //read complex if ( mlArray.isComplex() ) { tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getImaginaryByteBuffer(), (MLNumericArray) mlArray ); } break; case MLArray.mxUINT64_CLASS: mlArray = new MLUInt64(name, dims, type, attributes); //read real tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getRealByteBuffer(), (MLNumericArray) mlArray ); //read complex if ( mlArray.isComplex() ) { tag = new ISMatTag(buf); tag.readToByteBuffer( ((MLNumericArray) mlArray).getImaginaryByteBuffer(), (MLNumericArray) mlArray ); } break; case MLArray.mxCHAR_CLASS: MLChar mlchar = new MLChar(name, dims, type, attributes); //read real tag = new ISMatTag(buf); // char[] ac = tag.readToCharArray(); String str = tag.readToString(); for ( int i = 0; i < str.length(); i++ ) { mlchar.setChar( str.charAt(i), i ); } mlArray = mlchar; break; case MLArray.mxSPARSE_CLASS: MLSparse sparse = new MLSparse(name, dims, attributes, nzmax); //read ir (row indices) tag = new ISMatTag(buf); int[] ir = tag.readToIntArray(); //read jc (column count) tag = new ISMatTag(buf); int[] jc = tag.readToIntArray(); //read pr (real part) tag = new ISMatTag(buf); double[] ad1 = tag.readToDoubleArray(); int count = 0; for (int column = 0; column < sparse.getN(); column++) { while(count < jc[column+1]) { sparse.setReal(ad1[count], ir[count], column); count++; } } //read pi (imaginary part) if ( sparse.isComplex() ) { tag = new ISMatTag(buf); double[] ad2 = tag.readToDoubleArray(); count = 0; for (int column = 0; column < sparse.getN(); column++) { while(count < jc[column+1]) { sparse.setImaginary(ad2[count], ir[count], column); count++; } } } mlArray = sparse; break; case MLArray.mxOPAQUE_CLASS: //read class name tag = new ISMatTag(buf); // class name String className = tag.readToString(); // System.out.println( "Class name: " + className ); // should be "java" // System.out.println( "Array name: " + name ); // the stored array name // read array name stored in dims (!) byte[] nn = new byte[dims.length]; for ( int i = 0; i < dims.length; i++ ) { nn[i] = (byte)dims[i]; } String arrName = new String(nn); // System.out.println( "Array name: " + arrName ); // next tag should be miMatrix ISMatTag contentTag = new ISMatTag(buf); if ( contentTag.type == MatDataTypes.miMATRIX ) { // should return UInt8 MLUInt8 content = (MLUInt8) readMatrix( buf, false ); // de-serialize object ObjectInputStream ois = new ObjectInputStream( new ByteBufferInputStream( content.getRealByteBuffer(), content.getRealByteBuffer().limit() ) ); try { Object o = ois.readObject(); mlArray = new MLJavaObject( arrName, className, o ); } catch (Exception e) { throw new IOException( e ); } finally { ois.close(); } } else { throw new IOException("Unexpected java object content"); } break; case MLArray.mxOBJECT_CLASS: //read class name tag = new ISMatTag(buf); // class name className = tag.readToString(); // TODO: currently copy pasted from structure struct = new MLStructure(name, dims, type, attributes); //field name lenght - this subelement always uses the compressed data element format tag = new ISMatTag(buf); maxlen = buf.getInt(); //maximum field length ////// read fields data as Int8 tag = new ISMatTag(buf); //calculate number of fields numOfFields = tag.size/maxlen; fieldNames = new String[numOfFields]; for ( int i = 0; i < numOfFields; i++ ) { byte[] names = new byte[maxlen]; buf.get(names); fieldNames[i] = zeroEndByteArrayToString(names); } buf.position( buf.position() + tag.padding ); //read fields for ( int index = 0; index < 1; index++ ) { for ( int i = 0; i < numOfFields; i++ ) { //read matrix recursively tag = new ISMatTag(buf); if ( tag.size > 0 ) { MLArray fieldValue = readMatrix( buf, false); struct.setField( fieldNames[i], fieldValue, index ); } else { struct.setField(fieldNames[i], new MLEmptyArray(), index); } } } mlArray = new MLObject( name, className, struct ); break; default: throw new MatlabIOException("Incorrect matlab array class: " + MLArray.typeToString(type) ); } return mlArray; } /** * Converts byte array to String. * * It assumes that String ends with \0 value. * * @param bytes byte array containing the string. * @return String retrieved from byte array. * @throws IOException if reading error occurred. */ private String zeroEndByteArrayToString(byte[] bytes) throws IOException { int i = 0; for ( i = 0; i < bytes.length && bytes[i] != 0; i++ ); return new String( bytes, 0, i ); } /** * Reads Matrix flags. * * Modifies buf position. * * @param buf ByteBuffer * @return flags int array * @throws IOException if reading from buffer fails */ private int[] readFlags(ByteBuffer buf) throws IOException { ISMatTag tag = new ISMatTag(buf); int[] flags = tag.readToIntArray(); return flags; } /** * Reads Matrix dimensions. * * Modifies buf position. * * @param buf ByteBuffer * @return dimensions int array * @throws IOException if reading from buffer fails */ private int[] readDimension(ByteBuffer buf ) throws IOException { ISMatTag tag = new ISMatTag(buf); int[] dims = tag.readToIntArray(); return dims; } /** * Reads Matrix name. * * Modifies buf position. * * @param buf ByteBuffer * @return name String * @throws IOException if reading from buffer fails */ private String readName(ByteBuffer buf) throws IOException { ISMatTag tag = new ISMatTag(buf); return tag.readToString(); } /** * Reads MAT-file header. * * Modifies buf position. * * @param buf * ByteBuffer * @throws IOException * if reading from buffer fails or if this is not a valid * MAT-file */ private void readHeader(ByteBuffer buf) throws IOException { //header values String description; int version; byte[] endianIndicator = new byte[2]; //descriptive text 116 bytes byte[] descriptionBuffer = new byte[116]; buf.get(descriptionBuffer); description = zeroEndByteArrayToString(descriptionBuffer); if ( !description.matches("MATLAB 5.0 MAT-file.*") ) { throw new MatlabIOException("This is not a valid MATLAB 5.0 MAT-file."); } //subsyst data offset 8 bytes buf.position( buf.position() + 8); byte[] bversion = new byte[2]; //version 2 bytes buf.get(bversion); //endian indicator 2 bytes buf.get(endianIndicator); //program reading the MAT-file must perform byte swapping to interpret the data //in the MAT-file correctly if ( (char)endianIndicator[0] == 'I' && (char)endianIndicator[1] == 'M') { byteOrder = ByteOrder.LITTLE_ENDIAN; version = bversion[1] & 0xff | bversion[0] << 8; } else { byteOrder = ByteOrder.BIG_ENDIAN; version = bversion[0] & 0xff | bversion[1] << 8; } buf.order( byteOrder ); matFileHeader = new MatFileHeader(description, version, endianIndicator); } /** * TAG operator. Facilitates reading operations. * * Note: reading from buffer modifies it's position * * @author Wojciech Gradkowski (wgradkowski@gmail.com) */ private static class ISMatTag extends MatTag { private final MatFileInputStream mfis; private final int padding; private final boolean compressed; public ISMatTag(ByteBuffer buf) throws IOException { //must call parent constructor super(0,0); int tmp = buf.getInt(); //data not packed in the tag if ( tmp >> 16 == 0 ) { type = tmp; size = buf.getInt(); compressed = false; } else //data _packed_ in the tag (compressed) { size = tmp >> 16; // 2 more significant bytes type = tmp & 0xffff; // 2 less significant bytes; compressed = true; } padding = getPadding(size, compressed); mfis = new MatFileInputStream(buf, type); } public void readToByteBuffer( ByteBuffer buff, ByteStorageSupport storage ) throws IOException { int elements = size/sizeOf(); mfis.readToByteBuffer( buff, elements, storage ); mfis.skip( padding ); } public byte[] readToByteArray() throws IOException { //allocate memory for array elements int elements = size/sizeOf(); byte[] ab = new byte[elements]; for ( int i = 0; i < elements; i++ ) { ab[i] = mfis.readByte(); } //skip padding mfis.skip( padding ); return ab; } public double[] readToDoubleArray() throws IOException { //allocate memory for array elements int elements = size/sizeOf(); double[] ad = new double[elements]; for ( int i = 0; i < elements; i++ ) { ad[i] = mfis.readDouble(); } //skip padding mfis.skip( padding ); return ad; } public int[] readToIntArray() throws IOException { //allocate memory for array elements int elements = size/sizeOf(); int[] ai = new int[elements]; for ( int i = 0; i < elements; i++ ) { ai[i] = mfis.readInt(); } //skip padding mfis.skip( padding ); return ai; } public String readToString() throws IOException { // byte[] bytes = readToByteArray(); return new String( bytes, "UTF-8" ); } public char[] readToCharArray() throws IOException { //allocate memory for array elements int elements = size/sizeOf(); char[] ac = new char[elements]; for ( int i = 0; i < elements; i++ ) { ac[i] = mfis.readChar(); } //skip padding mfis.skip( padding ); return ac; } } }