Index: TarBuffer.java =================================================================== --- TarBuffer.java (revision 1501621) +++ TarBuffer.java (working copy) @@ -49,11 +49,11 @@ // TODO make these final? (would need to change close() method) private InputStream inStream; private OutputStream outStream; - private final int blockSize; - private final int recordSize; - private final int recsPerBlock; - private final byte[] blockBuffer; - private final byte[] eofRecord; + private final int blockSize; + private final int recordSize; + private final int recsPerBlock; + private final byte[] blockBuffer; + private final byte[] eofRecord; private int currBlkIdx; private int currRecIdx; @@ -126,7 +126,10 @@ ? DEFAULT_EOF_RECORD : new byte[recordSize]; if (this.inStream != null) { + // on first read, index set to zero this.currBlkIdx = -1; + + // on first read, index set to zero this.currRecIdx = this.recsPerBlock; } else { this.currBlkIdx = 0; @@ -171,12 +174,45 @@ } if (currRecIdx >= recsPerBlock && !readBlock()) { - return; // UNDONE + return; } currRecIdx++; } + + /** + * Skip n number of blocks. + * + * @param numBlocks + * Number of blocks to skip + * @throws IOException + * on stream error + */ + public void skipBlocks(long numBlocks) throws IOException { + if (inStream == null) { + throw new IOException("input buffer is closed"); + } + if (this.currBlkIdx < 0) + { + this.currBlkIdx = 0; + } + if (numBlocks > 0) + { + int oldRecIdx = currRecIdx; + long numBlockSkipped = numBlocks - 1; + + inStream.skip(numBlockSkipped * (long)blockSize); + currBlkIdx += numBlockSkipped; + + // reset the block buffer + readBlock(); + + // readBlock deletes old count + currRecIdx = oldRecIdx; + } + } + /** * Read a record from the input stream and return the data. * @@ -185,10 +221,7 @@ */ public byte[] readRecord() throws IOException { if (inStream == null) { - if (outStream == null) { - throw new IOException("input buffer is closed"); - } - throw new IOException("reading from an output buffer"); + throw new IOException("input buffer is closed"); } if (currRecIdx >= recsPerBlock && !readBlock()) { @@ -207,62 +240,56 @@ } /** + * inStream cannot be null + * * @return false if End-Of-File, else true */ - private boolean readBlock() throws IOException { - if (inStream == null) { - throw new IOException("reading from an output buffer"); - } - - currRecIdx = 0; - + private boolean readBlock() throws IOException + { int offset = 0; int bytesNeeded = blockSize; + + long numBytes = inStream.read(blockBuffer, offset, bytesNeeded); + while (numBytes != bytesNeeded && numBytes != -1) + { + offset += numBytes; + bytesNeeded -= numBytes; + numBytes = inStream.read(blockBuffer, offset, bytesNeeded); + } - while (bytesNeeded > 0) { - long numBytes = inStream.read(blockBuffer, offset, - bytesNeeded); + // + // NOTE + // We have fit EOF, and the block is not full! + // + // This is a broken archive. It does not follow the standard + // blocking algorithm. However, because we are generous, and + // it requires little effort, we will simply ignore the error + // and continue as if the entire block were read. This does + // not appear to break anything upstream. We used to return + // false in this case. + // + // Thanks to 'Yohann.Roussel@alcatel.fr' for this fix. + // + if (numBytes == -1) + { + // See http://issues.apache.org/bugzilla/show_bug.cgi?id=39924 + // Did the first read and got EOF, so return EOF + if (offset == 0) + { + return false; + } + // However, just leaving the unread portion of the buffer dirty does + // cause problems in some cases. This problem is described in + // http://issues.apache.org/bugzilla/show_bug.cgi?id=29877 // - // NOTE - // We have fit EOF, and the block is not full! - // - // This is a broken archive. It does not follow the standard - // blocking algorithm. However, because we are generous, and - // it requires little effort, we will simply ignore the error - // and continue as if the entire block were read. This does - // not appear to break anything upstream. We used to return - // false in this case. - // - // Thanks to 'Yohann.Roussel@alcatel.fr' for this fix. - // - if (numBytes == -1) { - if (offset == 0) { - // Ensure that we do not read gigabytes of zeros - // for a corrupt tar file. - // See http://issues.apache.org/bugzilla/show_bug.cgi?id=39924 - return false; - } - // However, just leaving the unread portion of the buffer dirty does - // cause problems in some cases. This problem is described in - // http://issues.apache.org/bugzilla/show_bug.cgi?id=29877 - // - // The solution is to fill the unused portion of the buffer with zeros. + // The solution is to fill the unused portion of the buffer with zeros. - Arrays.fill(blockBuffer, offset, offset + bytesNeeded, (byte) 0); - - break; - } - - offset += numBytes; - bytesNeeded -= numBytes; - - if (numBytes != blockSize) { - // TODO: Incomplete Read occured - throw exception? - } + Arrays.fill(blockBuffer, offset, offset + bytesNeeded, (byte) 0); } - currBlkIdx++; + currBlkIdx += 1; + currRecIdx = 0; return true; } @@ -293,11 +320,9 @@ * @throws IOException on error */ public void writeRecord(byte[] record) throws IOException { - if (outStream == null) { - if (inStream == null){ + if (outStream == null) + { throw new IOException("Output buffer is closed"); - } - throw new IOException("writing to an input buffer"); } if (record.length != recordSize) { @@ -329,10 +354,7 @@ */ public void writeRecord(byte[] buf, int offset) throws IOException { if (outStream == null) { - if (inStream == null){ - throw new IOException("Output buffer is closed"); - } - throw new IOException("writing to an input buffer"); + throw new IOException("Output buffer is closed"); } if ((offset + recordSize) > buf.length) { @@ -355,11 +377,9 @@ /** * Write a TarBuffer block to the archive. + * outStream cannot be null */ private void writeBlock() throws IOException { - if (outStream == null) { - throw new IOException("writing to an input buffer"); - } outStream.write(blockBuffer, 0, blockSize); outStream.flush();