/**
* Skip length bytes The same as readMultiPageData() without returning a result
*
* @param length number of bytes to skip
* @param page current page
* @param curPageOff in (current) and out (new) parameter at index 0
* @param nextPage in (current) and out (new) parameter at index 0
* @return current page
*/
public int skipMultiPageBytes(int length, int page, int[] curPageOff, int[] nextPage)
throws IOException {
int pageCounter = curPageOff[0];
int curNextPage = nextPage[0];
int curPage = page;
int dct = 0;
while (dct < length) {
int len = PAGESIZE - pageCounter;
if (len <= 0) {
if (curNextPage <= 0) throw new IOException("not enough pages to skip");
BlockFile.pageSeek(this.file, curNextPage);
int magic = this.file.readInt();
if (magic != MAGIC_CONT)
throw new IOException(
"Bad SkipSpan continuation magic number 0x"
+ Integer.toHexString(magic)
+ " on page "
+ curNextPage);
curPage = curNextPage;
curNextPage = this.file.readUnsignedInt();
pageCounter = BSkipSpan.CONT_HEADER_LEN;
len = PAGESIZE - pageCounter;
}
int res = Math.min(len, length - dct);
this.file.skipBytes(res);
pageCounter += res;
dct += res;
}
nextPage[0] = curNextPage;
curPageOff[0] = pageCounter;
return curPage;
}
/**
* Read bytes
*
* @param arr fill this array fully with data
* @param page current page
* @param curPageOff in (current) and out (new) parameter at index 0
* @param nextPage in (current) and out (new) parameter at index 0
* @return current page
*/
public int readMultiPageData(byte[] arr, int page, int[] curPageOff, int[] nextPage)
throws IOException {
int pageCounter = curPageOff[0];
int curNextPage = nextPage[0];
int curPage = page;
int dct = 0;
while (dct < arr.length) {
int len = PAGESIZE - pageCounter;
if (len <= 0) {
if (curNextPage <= 0)
throw new IOException("not enough pages to read data still need " + (arr.length - dct));
BlockFile.pageSeek(this.file, curNextPage);
int magic = this.file.readInt();
if (magic != MAGIC_CONT)
throw new IOException(
"Bad SkipSpan continuation magic number 0x"
+ Integer.toHexString(magic)
+ " on page "
+ curNextPage);
curPage = curNextPage;
curNextPage = this.file.readUnsignedInt();
pageCounter = BSkipSpan.CONT_HEADER_LEN;
len = PAGESIZE - pageCounter;
}
int res = this.file.read(arr, dct, Math.min(len, arr.length - dct));
if (res == -1) {
throw new IOException();
}
pageCounter += Math.min(len, arr.length - dct);
dct += res;
}
nextPage[0] = curNextPage;
curPageOff[0] = pageCounter;
return curPage;
}
/**
* Run an integrity check on the blockfile and all the skiplists in it.
*
* <p>WARNING: This only works on skiplists using UTF8StringBytes as a key serializer, unless the
* exception has been coded in bfck below. Will CORRUPT other skiplists.
*/
public static void main(String args[]) {
if (args.length != 1) {
System.err.println("Usage: BlockFile file");
return;
}
boolean init = !(new File(args[0])).exists();
try {
RAIFile raif = new RAIFile(new File(args[0]), true, true);
BlockFile bf = new BlockFile(raif, init);
bf.bfck(true);
bf.close();
raif.close();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Write bytes This will allocate additional continuation pages as necessary.
*
* @param data data to write
* @param page current page
* @param curPageOff in (current) and out (new) parameter at index 0
* @param nextPage in (current) and out (new) parameter at index 0
* @return current page
*/
public int writeMultiPageData(byte[] data, int page, int[] curPageOff, int[] nextPage)
throws IOException {
int pageCounter = curPageOff[0];
int curNextPage = nextPage[0];
int curPage = page;
int dct = 0;
while (dct < data.length) {
int len = PAGESIZE - pageCounter;
if (len <= 0) {
if (curNextPage == 0) {
curNextPage = this.allocPage();
BlockFile.pageSeek(this.file, curNextPage);
this.file.writeInt(MAGIC_CONT);
this.file.writeInt(0);
BlockFile.pageSeek(this.file, curPage);
this.file.skipBytes(4); // skip magic
this.file.writeInt(curNextPage);
}
BlockFile.pageSeek(this.file, curNextPage);
curPage = curNextPage;
int magic = this.file.readInt();
if (magic != MAGIC_CONT)
throw new IOException(
"Bad SkipSpan continuation magic number 0x"
+ Integer.toHexString(magic)
+ " on page "
+ curNextPage);
curNextPage = this.file.readUnsignedInt();
pageCounter = BSkipSpan.CONT_HEADER_LEN;
len = PAGESIZE - pageCounter;
}
this.file.write(data, dct, Math.min(len, data.length - dct));
pageCounter += Math.min(len, data.length - dct);
dct += Math.min(len, data.length - dct);
}
nextPage[0] = curNextPage;
curPageOff[0] = pageCounter;
return curPage;
}