Example usage for java.util.zip GZIPInputStream read

Introduction

In this page you can find the example usage for java.util.zip GZIPInputStream read.

Prototype

public int read() throws IOException 

Source Link

Document

Reads a byte of uncompressed data.

Usage

From source file:edu.harvard.iq.dvn.ingest.dsb.SubsettableFileChecker.java

/**
 * test this byte buffer against R data file
 *
 *///from   ww  w .  java2 s .  c  om
public String testRDAformat(MappedByteBuffer buff) {
    String result = null;
    buff.rewind();

    boolean DEBUG = false;
    if (DEBUG) {
        out.println("applying the RData test\n");
        out.println("buffer capacity=" + buff.capacity());
    }
    if (DEBUG) {
        byte[] rawhdr = new byte[4];
        buff.get(rawhdr, 0, 4);
        for (int j = 0; j < 4; j++) {
            out.printf("%02X ", rawhdr[j]);
        }
        out.println();
        buff.rewind();
    }
    // get the first 4 bytes as an int and check its value; 
    // if it is 0x1F8B0800, then gunzip and its first 4 bytes
    int magicNumber = buff.getInt();

    if (DEBUG) {
        out.println("magicNumber in decimal =" + magicNumber);
        out.println("in binary=" + Integer.toBinaryString(magicNumber));
        out.println("in oct=" + Integer.toOctalString(magicNumber));
        out.println("in hex=" + Integer.toHexString(magicNumber));
    }
    try {
        if (magicNumber == 0x1F8B0800) {
            if (DEBUG) {
                out.println("magicNumber is GZIP");
            }
            // gunzip the first 5 bytes and check their bye-pattern

            // get gzip buffer size

            int gzip_buffer_size = this.getGzipBufferSize(buff);

            byte[] hdr = new byte[gzip_buffer_size];
            buff.get(hdr, 0, gzip_buffer_size);

            GZIPInputStream gzin = new GZIPInputStream(new ByteArrayInputStream(hdr));

            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < RDA_HEADER_SIZE; i++) {
                sb.append(String.format("%02X", gzin.read()));
            }
            String fisrt5bytes = sb.toString();

            result = this.checkUncompressedFirst5bytes(fisrt5bytes);
            // end of compressed case
        } else {
            // uncompressed case?
            if (DEBUG) {
                out.println("magicNumber is not GZIP:" + magicNumber);
                out.println("test as an uncompressed RData file");
            }

            buff.rewind();
            byte[] uchdr = new byte[5];
            buff.get(uchdr, 0, 5);
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < uchdr.length; i++) {
                sb.append(String.format("%02X", uchdr[i]));
            }
            String fisrt5bytes = sb.toString();

            result = this.checkUncompressedFirst5bytes(fisrt5bytes);
            // end of uncompressed case
        }
    } catch (IOException ex) {
        ex.printStackTrace();
    }
    return result;
}

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From source file:edu.harvard.iq.dataverse.ingest.IngestableDataChecker.java

/**
 * test this byte buffer against R data file
 *
 *//*from w  ww  .jav  a 2s . c om*/
public String testRDAformat(MappedByteBuffer buff) {
    String result = null;
    buff.rewind();

    if (buff.capacity() < 4) {
        return null;
    }

    boolean DEBUG = false;
    if (DEBUG) {
        out.println("applying the RData test\n");
        out.println("buffer capacity=" + buff.capacity());
    }
    if (DEBUG) {
        byte[] rawhdr = new byte[4];
        buff.get(rawhdr, 0, 4);
        for (int j = 0; j < 4; j++) {
            out.printf("%02X ", rawhdr[j]);
        }
        out.println();
        buff.rewind();
    }
    // get the first 4 bytes as an int and check its value; 
    // if it is 0x1F8B0800, then gunzip and its first 4 bytes
    int magicNumber = buff.getInt();

    if (DEBUG) {
        out.println("magicNumber in decimal =" + magicNumber);
        out.println("in binary=" + Integer.toBinaryString(magicNumber));
        out.println("in oct=" + Integer.toOctalString(magicNumber));
        out.println("in hex=" + Integer.toHexString(magicNumber));
    }
    try {
        if (magicNumber == 0x1F8B0800) {
            if (DEBUG) {
                out.println("magicNumber is GZIP");
            }
            // gunzip the first 5 bytes and check their bye-pattern

            // get gzip buffer size

            int gzip_buffer_size = this.getGzipBufferSize(buff);

            byte[] hdr = new byte[gzip_buffer_size];
            buff.get(hdr, 0, gzip_buffer_size);

            GZIPInputStream gzin = new GZIPInputStream(new ByteArrayInputStream(hdr));

            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < RDA_HEADER_SIZE; i++) {
                sb.append(String.format("%02X", gzin.read()));
            }
            String fisrt5bytes = sb.toString();

            result = this.checkUncompressedFirst5bytes(fisrt5bytes);
            // end of compressed case
        } else {
            // uncompressed case?
            if (DEBUG) {
                out.println("magicNumber is not GZIP:" + magicNumber);
                out.println("test as an uncompressed RData file");
            }

            buff.rewind();
            byte[] uchdr = new byte[5];
            buff.get(uchdr, 0, 5);
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < uchdr.length; i++) {
                sb.append(String.format("%02X", uchdr[i]));
            }
            String fisrt5bytes = sb.toString();

            result = this.checkUncompressedFirst5bytes(fisrt5bytes);
            // end of uncompressed case
        }
    } catch (IOException ex) {
        ex.printStackTrace();
    }
    return result;
}

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