package org.rrd4j.core.jrrd;
import java.io.IOException;
/**
* Instances of this class model the header section of an RRD file.
*
* @author <a href="mailto:ciaran@codeloop.com">Ciaran Treanor</a>
* @version $Revision: 1.1 $
*/
public class Header implements Constants {
private static final double FLOAT_COOKIE = 8.642135E130;
private static final long offset = 0;
private final long size;
final String version;
private final int iVersion;
/** Number of data sources */
final int dsCount;
/** Number of archives within file */
final int rraCount;
final int pdpStep;
Header(RRDFile file) throws IOException {
if (!file.readString(4).equals(COOKIE)) {
throw new IOException("Invalid COOKIE");
}
version = file.readString(5);
try {
iVersion = Integer.parseInt(version);
} catch (NumberFormatException e) {
throw new RuntimeException("Unsupported RRD version (" + version + ")");
}
if (iVersion > MAX_SUPPORTED_VERSION) {
throw new RuntimeException("Unsupported RRD version (" + version + ")");
}
file.align();
// Consume the FLOAT_COOKIE
double cookie = file.readDouble();
if(cookie != FLOAT_COOKIE) {
throw new RuntimeException("This RRD was created on another architecture");
}
dsCount = file.readLong();
rraCount = file.readLong();
pdpStep = file.readLong();
// Skip rest of stat_head_t.par
@SuppressWarnings("unused")
UnivalArray par = file.getUnivalArray(10);
size = file.getFilePointer() - offset;
}
/**
* Returns the version of the database.
*
* @return the version of the database.
*/
public String getVersion() {
return version;
}
/**
* Returns the version of the database as an integer.
*
* @return the version of the database.
*/
public int getVersionAsInt() {
return iVersion;
}
/**
* Returns the number of <code>DataSource</code>s in the database.
*
* @return the number of <code>DataSource</code>s in the database.
*/
public int getDSCount() {
return dsCount;
}
/**
* Returns the number of <code>Archive</code>s in the database.
*
* @return the number of <code>Archive</code>s in the database.
*/
public int getRRACount() {
return rraCount;
}
/**
* Returns the primary data point interval in seconds.
*
* @return the primary data point interval in seconds.
*/
public int getPDPStep() {
return pdpStep;
}
/**
* Returns a summary the contents of this header.
*
* @return a summary of the information contained in this header.
*/
public String toString() {
StringBuilder sb = new StringBuilder("[Header: OFFSET=0x00, SIZE=0x");
sb.append(Long.toHexString(size));
sb.append(", version=");
sb.append(version);
sb.append(", dsCount=");
sb.append(dsCount);
sb.append(", rraCount=");
sb.append(rraCount);
sb.append(", pdpStep=");
sb.append(pdpStep);
sb.append("]");
return sb.toString();
}
}