/**
* Creates a new instance of IndexedChronicle as specified by the provided {@link
* net.openhft.chronicle.ChronicleConfig} and having the specified <tt>basePath</tt> (the base
* name of the two backing files).
*
* @param basePath the base name of the files backing this IndexChronicle
* @param config the ChronicleConfig based on which the current IndexChronicle should be
* constructed
* @throws FileNotFoundException if the <tt>basePath</tt> string does not denote an existing,
* writable regular file and a new regular file of that name cannot be created, or if some
* other error occurs while opening or creating the file
*/
public IndexedChronicle(@NotNull String basePath, @NotNull ChronicleConfig config)
throws IOException {
this.basePath = basePath;
this.config = config.clone();
File parentFile = new File(basePath).getParentFile();
if (parentFile != null) {
parentFile.mkdirs();
}
this.indexFileCache =
VanillaMappedBlocks.readWrite(new File(basePath + ".index"), config.indexBlockSize());
this.dataFileCache =
VanillaMappedBlocks.readWrite(new File(basePath + ".data"), config.dataBlockSize());
findTheLastIndex();
}
private long findTheLastIndex0() {
long size = 0;
try {
size = indexFileCache.size();
} catch (Exception e) {
return -1;
}
if (size <= 0) {
return -1;
}
int indexBlockSize = config.indexBlockSize();
for (long block = size / indexBlockSize - 1; block >= 0; block--) {
VanillaMappedBytes mbb = null;
try {
mbb = indexFileCache.acquire(block);
} catch (IOException e) {
continue;
}
if (block > 0 && mbb.readLong(0) == 0) {
continue;
}
int cacheLineSize = config.cacheLineSize();
for (int pos = 0; pos < indexBlockSize; pos += cacheLineSize) {
// if the next line is blank
if (pos + cacheLineSize >= indexBlockSize || mbb.readLong(pos + cacheLineSize) == 0) {
// last cache line.
int pos2 = 8;
for (pos2 = 8; pos2 < cacheLineSize; pos2 += 4) {
if (mbb.readInt(pos + pos2) == 0) {
break;
}
}
return (block * indexBlockSize + pos) / cacheLineSize * (cacheLineSize / 4 - 2)
+ pos2 / 4
- 3;
}
}
return (block + 1) * indexBlockSize / cacheLineSize * (cacheLineSize / 4 - 2);
}
return -1;
}