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Posted to commits@commons.apache.org by eb...@apache.org on 2012/03/12 11:47:15 UTC
svn commit: r1299618 -
/commons/proper/csv/trunk/src/main/java/org/apache/commons/csv/ExtendedBufferedReader.java
Author: ebourg
Date: Mon Mar 12 10:47:15 2012
New Revision: 1299618
URL: http://svn.apache.org/viewvc?rev=1299618&view=rev
Log:
Optimized ExtendedBufferedReader as suggested by Bob Smith in CSV-42 (improves the performance by 30%)
Modified:
commons/proper/csv/trunk/src/main/java/org/apache/commons/csv/ExtendedBufferedReader.java
Modified: commons/proper/csv/trunk/src/main/java/org/apache/commons/csv/ExtendedBufferedReader.java
URL: http://svn.apache.org/viewvc/commons/proper/csv/trunk/src/main/java/org/apache/commons/csv/ExtendedBufferedReader.java?rev=1299618&r1=1299617&r2=1299618&view=diff
==============================================================================
--- commons/proper/csv/trunk/src/main/java/org/apache/commons/csv/ExtendedBufferedReader.java (original)
+++ commons/proper/csv/trunk/src/main/java/org/apache/commons/csv/ExtendedBufferedReader.java Mon Mar 12 10:47:15 2012
@@ -39,44 +39,23 @@ class ExtendedBufferedReader extends Buf
/** Undefined state for the lookahead char */
static final int UNDEFINED = -2;
- /** The lookahead chars */
- private int lookaheadChar = UNDEFINED;
-
/** The last char returned */
private int lastChar = UNDEFINED;
/** The line counter */
private int lineCounter = 0;
- private CharBuffer line = new CharBuffer();
-
/**
* Created extended buffered reader using default buffer-size
*/
ExtendedBufferedReader(Reader r) {
super(r);
- /* note uh: do not fetch the first char here,
- * because this might block the method!
- */
}
- /**
- * Reads the next char from the input stream.
- *
- * @return the next char or END_OF_STREAM if end of stream has been reached.
- */
@Override
public int read() throws IOException {
- // initialize the lookahead
- if (lookaheadChar == UNDEFINED) {
- lookaheadChar = super.read();
- }
- lastChar = lookaheadChar;
- if (super.ready()) {
- lookaheadChar = super.read();
- } else {
- lookaheadChar = UNDEFINED;
- }
+ lastChar = super.read();
+
if (lastChar == '\n') {
lineCounter++;
}
@@ -84,131 +63,74 @@ class ExtendedBufferedReader extends Buf
}
/**
- * Returns the last read character again.
- *
- * @return the last read char or UNDEFINED
+ * Returns the last character that was read as an integer (0 to 65535). This
+ * will be the last character returned by any of the read methods. This will
+ * not include a character read using the {@link #peek()} method. If no
+ * character has been read then this will return {@link #UNDEFINED}. If the
+ * end of the stream was reached on the last read then this will return
+ * {@link #END_OF_STREAM}.
+ *
+ * @return the last character that was read
*/
int readAgain() {
return lastChar;
}
- /**
- * Non-blocking reading of len chars into buffer buf starting
- * at bufferposition off.
- * <p/>
- * performs an iterative read on the underlying stream
- * as long as the following conditions hold:
- * - less than len chars have been read
- * - end of stream has not been reached
- * - next read is not blocking
- *
- * @return nof chars actually read or END_OF_STREAM
- */
@Override
public int read(char[] buf, int off, int len) throws IOException {
- // do not claim if len == 0
if (len == 0) {
return 0;
}
-
- // init lookahead, but do not block !!
- if (lookaheadChar == UNDEFINED) {
- if (ready()) {
- lookaheadChar = super.read();
- } else {
- return -1;
- }
- }
- // 'first read of underlying stream'
- if (lookaheadChar == -1) {
- return -1;
- }
- // continue until the lookaheadChar would block
- int cOff = off;
- while (len > 0 && ready()) {
- if (lookaheadChar == -1) {
- // eof stream reached, do not continue
- return cOff - off;
- } else {
- buf[cOff++] = (char) lookaheadChar;
- if (lookaheadChar == '\n') {
+
+ int l = super.read(buf, off, len);
+
+ if (l > 0) {
+ lastChar = buf[off + l - 1];
+
+ for (int i = off; i < off + l; i++) {
+ if (buf[i] == '\n') {
lineCounter++;
}
- lastChar = lookaheadChar;
- lookaheadChar = super.read();
- len--;
}
+
+ } else if (l == -1) {
+ lastChar = END_OF_STREAM;
}
- return cOff - off;
+
+ return l;
}
- /**
- * @return A String containing the contents of the line, not
- * including any line-termination characters, or null
- * if the end of the stream has been reached
- */
@Override
public String readLine() throws IOException {
+ String line = super.readLine();
- if (lookaheadChar == UNDEFINED) {
- lookaheadChar = super.read();
- }
-
- line.clear(); //reuse
-
- // return null if end of stream has been reached
- if (lookaheadChar == END_OF_STREAM) {
- return null;
- }
- // do we have a line termination already
- char laChar = (char) lookaheadChar;
- if (laChar == '\n' || laChar == '\r') {
- lastChar = lookaheadChar;
- lookaheadChar = super.read();
- // ignore '\r\n' as well
- if ((char) lookaheadChar == '\n') {
- lastChar = lookaheadChar;
- lookaheadChar = super.read();
+ if (line != null) {
+ if (line.length() > 0) {
+ lastChar = line.charAt(line.length() - 1);
}
lineCounter++;
- return line.toString();
- }
-
- // create the rest-of-line return and update the lookahead
- line.append(laChar);
- String restOfLine = super.readLine(); // TODO involves copying
- lastChar = lookaheadChar;
- lookaheadChar = super.read();
- if (restOfLine != null) {
- line.append(restOfLine);
+ } else {
+ lastChar = END_OF_STREAM;
}
- lineCounter++;
- return line.toString();
- }
- /**
- * Unsupported
- */
- @Override
- public long skip(long n) throws IllegalArgumentException, IOException {
- throw new UnsupportedOperationException("CSV has no reason to implement this");
+ return line;
}
/**
- * Returns the next char in the stream without consuming it.
- *
- * Remember the next char read by read(..) will always be
- * identical to lookAhead().
- *
- * @return the next char (without consuming it) or END_OF_STREAM
+ * Returns the next character in the current reader without consuming it. So
+ * the next call to {@link #read()} will still return this value.
+ *
+ * @return the next character
+ *
+ * @throws IOException if there is an error in reading
*/
int lookAhead() throws IOException {
- if (lookaheadChar == UNDEFINED) {
- lookaheadChar = super.read();
- }
- return lookaheadChar;
- }
+ super.mark(1);
+ int c = super.read();
+ super.reset();
+ return c;
+ }
/**
* Returns the nof line read
@@ -216,16 +138,6 @@ class ExtendedBufferedReader extends Buf
* @return the current-line-number (or -1)
*/
int getLineNumber() {
- return lineCounter > -1 ? lineCounter : -1;
- }
-
- /**
- * Unsupported.
- * @throws UnsupportedOperationException if invoked
- */
- @Override
- public boolean markSupported() {
- throw new UnsupportedOperationException("CSV has no reason to implement this");
+ return lineCounter;
}
-
}