iemejia commented on code in PR #3565:
URL: https://github.com/apache/parquet-java/pull/3565#discussion_r3343041130
##########
parquet-column/src/main/java/org/apache/parquet/column/values/plain/BooleanPlainValuesReader.java:
##########
@@ -18,57 +18,65 @@
*/
package org.apache.parquet.column.values.plain;
-import static org.apache.parquet.column.values.bitpacking.Packer.LITTLE_ENDIAN;
-
import java.io.IOException;
+import java.nio.ByteBuffer;
import org.apache.parquet.bytes.ByteBufferInputStream;
+import org.apache.parquet.bytes.BytesUtils;
import org.apache.parquet.column.values.ValuesReader;
-import org.apache.parquet.column.values.bitpacking.ByteBitPackingValuesReader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
- * encodes boolean for the plain encoding: one bit at a time (0 = false)
+ * Decodes PLAIN-encoded booleans: one bit per value, packed 8 per byte,
little-endian
+ * bit order (bit 0 of each byte is the first value).
+ *
+ * <p>Direct bit extraction from the page ByteBuffer avoids the overhead of
the generic
+ * bit-packing machinery ({@code ByteBitPackingValuesReader}) and intermediate
+ * {@code int[8]} buffers.
*/
public class BooleanPlainValuesReader extends ValuesReader {
private static final Logger LOG =
LoggerFactory.getLogger(BooleanPlainValuesReader.class);
- private ByteBitPackingValuesReader in = new ByteBitPackingValuesReader(1,
LITTLE_ENDIAN);
+ private byte[] pageData;
+ private int pageOffset;
+ private int bitIndex;
- /**
- * {@inheritDoc}
- *
- * @see org.apache.parquet.column.values.ValuesReader#readBoolean()
- */
@Override
- public boolean readBoolean() {
- return in.readInteger() == 0 ? false : true;
+ public void initFromPage(int valueCount, ByteBufferInputStream stream)
throws IOException {
+ LOG.debug("init from page at offset {} for length {}", stream.position(),
stream.available());
+ int effectiveBitLength = valueCount; // bitWidth = 1
+ int length = BytesUtils.paddedByteCountFromBits(effectiveBitLength);
+ length = Math.min(length, stream.available());
+ ByteBuffer buf = stream.slice(length);
+
+ // Bulk access: use backing array directly if available, otherwise copy
once.
+ if (buf.hasArray()) {
+ pageData = buf.array();
+ pageOffset = buf.arrayOffset() + buf.position();
+ } else {
+ pageData = new byte[length];
+ buf.get(pageData);
+ pageOffset = 0;
+ }
+ bitIndex = 0;
+ updateNextOffset(length);
}
- /**
- * {@inheritDoc}
- *
- * @see org.apache.parquet.column.values.ValuesReader#skip()
- */
@Override
- public void skip() {
- in.readInteger();
+ public boolean readBoolean() {
+ int byteIdx = pageOffset + (bitIndex >>> 3);
+ int bitPos = bitIndex & 7;
+ bitIndex++;
+ return ((pageData[byteIdx] >>> bitPos) & 1) != 0;
}
- /**
- * {@inheritDoc}
- *
- * @see org.apache.parquet.column.values.ValuesReader#initFromPage(int,
ByteBufferInputStream)
- */
@Override
- public void initFromPage(int valueCount, ByteBufferInputStream stream)
throws IOException {
- LOG.debug("init from page at offset {} for length {}", stream.position(),
stream.available());
- this.in.initFromPage(valueCount, stream);
+ public void skip() {
+ bitIndex++;
}
- @Deprecated
@Override
- public int getNextOffset() {
- return in.getNextOffset();
+ public void skip(int n) {
+ bitIndex += n;
Review Comment:
Done. Added a `bitCount` field (set to `length * 8` in `initFromPage`) and
an explicit bounds check in `readBoolean()` that throws
`ParquetDecodingException` with a descriptive message when attempting to read
beyond the page boundary.
##########
parquet-column/src/main/java/org/apache/parquet/column/values/plain/PlainValuesReader.java:
##########
@@ -19,120 +19,91 @@
package org.apache.parquet.column.values.plain;
import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
import org.apache.parquet.bytes.ByteBufferInputStream;
-import org.apache.parquet.bytes.LittleEndianDataInputStream;
import org.apache.parquet.column.values.ValuesReader;
-import org.apache.parquet.io.ParquetDecodingException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
- * Plain encoding for float, double, int, long
+ * Plain encoding for float, double, int, long.
+ *
+ * <p>Reads directly from a {@link ByteBuffer} with {@link
ByteOrder#LITTLE_ENDIAN} byte order,
+ * bypassing the deprecated {@code LittleEndianDataInputStream} wrapper to
avoid per-value virtual
+ * dispatch overhead. The underlying page data is obtained as a single
contiguous {@link ByteBuffer}
+ * via {@link ByteBufferInputStream#slice(int)}.
*/
public abstract class PlainValuesReader extends ValuesReader {
private static final Logger LOG =
LoggerFactory.getLogger(PlainValuesReader.class);
- protected LittleEndianDataInputStream in;
+ protected ByteBuffer buffer;
@Override
public void initFromPage(int valueCount, ByteBufferInputStream stream)
throws IOException {
LOG.debug("init from page at offset {} for length {}", stream.position(),
stream.available());
- this.in = new LittleEndianDataInputStream(stream.remainingStream());
+ int available = stream.available();
+ if (available > 0) {
+ this.buffer = stream.slice(available).order(ByteOrder.LITTLE_ENDIAN);
+ } else {
+ this.buffer = ByteBuffer.allocate(0).order(ByteOrder.LITTLE_ENDIAN);
+ }
}
@Override
public void skip() {
skip(1);
}
- void skipBytesFully(int n) throws IOException {
- int skipped = 0;
- while (skipped < n) {
- skipped += in.skipBytes(n - skipped);
- }
- }
-
public static class DoublePlainValuesReader extends PlainValuesReader {
@Override
public void skip(int n) {
- try {
- skipBytesFully(n * 8);
- } catch (IOException e) {
- throw new ParquetDecodingException("could not skip " + n + " double
values", e);
- }
+ buffer.position(buffer.position() + n * 8);
Review Comment:
Done. Applied `Math.multiplyExact` in all `skip(int n)` methods:
`Math.multiplyExact(n, 8)` for double/long, `Math.multiplyExact(n, 4)` for
float/int, and `Math.multiplyExact(n, length)` in
`FixedLenByteArrayPlainValuesReader`. Overflow now produces an
`ArithmeticException` which gets caught and wrapped in
`ParquetDecodingException`.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
