package tuning.string;
import java.nio.*;
import java.io.*;
import java.util.regex.*;
public class FilterComparison2
{
static char[] NewLine;
static int count;
public static char[] buf;
static
{
String NewLineStr = System.getProperty("line.separator");
NewLine = new char[NewLineStr.length()];
NewLineStr.getChars(0, NewLine.length, NewLine, 0);
}
public static void main(String[] args)
{
test(args);
if (args.length > 2)
test(args);
}
public static void test(String[] args)
{
try
{
if (buf == null)
{
File f = new File(args[1]);
buf = new char[(int) f.length()];
FileReader r = new FileReader(args[1]);
int len = 0, len2;
while( (len2 = r.read(buf,len,buf.length-len)) > 0) {len+=len2;}
if (len != buf.length) throw new Exception("Didn't read the whole file");
r.close();
}
long time = System.currentTimeMillis();
filter3(args[0], args[1], false);
time = System.currentTimeMillis() - time;
System.out.println("filter3 time (millis) = " + time);
System.gc();
System.gc();
System.gc();
System.gc();
time = System.currentTimeMillis();
filter1(args[0], args[1], false);
time = System.currentTimeMillis() - time;
System.out.println("filter1 time (millis) = " + time);
System.gc();
System.gc();
System.gc();
System.gc();
time = System.currentTimeMillis();
filter2(args[0], args[1], false);
time = System.currentTimeMillis() - time;
System.out.println("filter2 time (millis) = " + time);
System.gc();
System.gc();
System.gc();
System.gc();
time = System.currentTimeMillis();
cfilter(args[0], args[1], false);
time = System.currentTimeMillis() - time;
System.out.println("cfilter time (millis) = " + time);
System.gc();
System.gc();
System.gc();
System.gc();
}
catch(Exception e){e.printStackTrace();}
}
public static void filter1(String filter, String filename, boolean print)
throws IOException
{
count = 0;
// BufferedReader rdr = new BufferedReader(new FileReader(filename));
BufferedReader rdr = new BufferedReader(new CharArrayReader(buf));
String line;
String ufilter = filter.toUpperCase();
while( (line = rdr.readLine()) != null)
{
if (line.toUpperCase().indexOf(ufilter) != -1)
{
count++;
if (print)
System.out.println(line);
}
}
System.out.println(count + " lines matched.");
rdr.close();
}
public static void filter2(String filter, String filename, boolean print)
throws IOException
{
count = 0;
// BufferedReader rdr = new BufferedReader(new FileReader(filename));
BufferedReader rdr = new BufferedReader(new CharArrayReader(buf));
String line;
int filterLength = filter.length();
while( (line = rdr.readLine()) != null)
{
for(int i = 0; i < line.length(); i++)
if (line.regionMatches(true, i, filter, 0, filterLength))
{
count++;
if (print)
System.out.println(line);
break;
}
}
System.out.println(count + " lines matched.");
rdr.close();
}
public static void filter3(String filter, String filename, boolean print)
throws IOException
{
count = 0;
Pattern p = Pattern.compile("^.*" + filter + ".*$", Pattern.MULTILINE | Pattern.CASE_INSENSITIVE);
CharBuffer cbuff = CharBuffer.wrap(buf);
Matcher m = p.matcher(cbuff);
while( m.find() )
{
count++;
if (print)
System.out.println(m.group());
}
System.out.println(count + " lines matched.");
}
public static void cfilter(String filter, String filename, boolean print)
throws IOException
{
MatchReader2.filter(filter, filename, print);
}
}
class MatchReader2
{
public static void filter(String filter, String filename, boolean print)
throws IOException
{
// MatchReader2 rdr = new MatchReader2(new FileReader(filename), filter);
MatchReader2 rdr = new MatchReader2(new CharArrayReader(FilterComparison2.buf), filter);
rdr.filter(print);
}
static final int BUFFER_SIZE = 8192;
char[] buffer;
int bufferSize;
int bufferPos;
char[] matchString;
Reader reader;
Writer sysout;
public MatchReader2(Reader rdr, String match)
throws IOException
{
reader = rdr;
matchString = new char[match.length()];
match.toUpperCase().getChars(0, match.length(), matchString, 0);
buffer = new char[BUFFER_SIZE];
bufferSize = 0;
bufferPos = 0;
sysout = new OutputStreamWriter(System.out);
fillBuffer();
}
/* return true if more characters were read, otherwise false */
private boolean fillBuffer()
throws IOException
{
int len;
boolean added = false;
while(bufferSize < buffer.length)
{
len = reader.read(buffer, bufferSize, buffer.length-bufferSize);
if (len <= 0)
return added;
else
bufferSize += len;
added = true;
}
return added;
}
public void filter(boolean print)
throws IOException
{
int count = 0;
while( nextMatchedLine() )
{
count++;
if (print)
printCurrentLine();
else
nextLine();
}
System.out.println(count + " lines matched.");
close();
}
public void close()
throws IOException
{
buffer = null;
matchString = null;
reader.close();
}
/* Return true if we matched a line,
* false if there were no more matches
*/
public boolean nextMatchedLine()
throws IOException
{
while(!scrollToNextMatchInCurrentBuffer())
{
if (!refillBuffer())
{
//No more characters to read, just make sure
//that no more lines are left in the buffer
return scrollToNextMatchInCurrentBuffer();
}
}
return true;
}
private boolean scrollToNextMatchInCurrentBuffer()
{
//Simple linear search
//No need to try to match beyond the end of the buffer
int highIdx = bufferSize-matchString.length;
for (; bufferPos <= highIdx; bufferPos++)
{
if (matches())
return true;
}
return false;
}
private boolean matches()
{
//Assume that this is only called if the match
//characters can fit into the remaining buffer
for(int j = 0; j < matchString.length ; j++)
if(Character.toUpperCase(buffer[bufferPos+j]) != matchString[j])
return false;
return true;
}
private boolean refillBuffer()
throws IOException
{
return refillBuffer(bufferSize - 1);
}
private boolean refillBuffer(int lastIdx)
throws IOException
{
//Find the start of the last line in the buffer,
//move that to the start of the buffer,
//then append some more to the buffer.
while( (lastIdx > 0) && (buffer[lastIdx] != '\n') && (buffer[lastIdx] != '\r') )
lastIdx--;
if ( (buffer[lastIdx] == '\n') || (buffer[lastIdx] == '\r') )
{
//Found the most recent newline character
bufferSize -= lastIdx+1;
System.arraycopy(buffer, lastIdx+1, buffer, 0, bufferSize);
bufferPos = 0; //be safe
return fillBuffer();
}
else
{
//reached the beginning of the buffer and we still don't have a newline
return fillBuffer();
}
}
/* Scroll to just after the next newline character */
public void nextLine()
throws IOException
{
while(!scrollToNextLineInCurrentBuffer())
{
if (!refillBuffer())
{
//No more characters to read, just make sure
//that no more lines are left in the buffer
scrollToNextLineInCurrentBuffer();
}
}
}
private boolean scrollToNextLineInCurrentBuffer()
{
//Simple linear search
//No need to try to match beyond the end of the buffer
int highIdx = bufferSize-1;
for (; bufferPos <= highIdx; bufferPos++)
{
if ( (buffer[bufferPos] == '\n') || (buffer[bufferPos] == '\r') )
{
bufferPos++;
return true;
}
}
return false;
}
private void printCurrentLine()
throws IOException
{
//Move the start of the current line back to beginning of
//the buffer, fill it up, and find the next line
refillBuffer(bufferPos);
scrollToNextLineInCurrentBuffer();
sysout.write(buffer, 0, bufferPos-1);
sysout.write(FilterComparison.NewLine);
sysout.flush();
}
}
|
