Skip to content

Commit

Permalink
Optimize code
Browse files Browse the repository at this point in the history
  • Loading branch information
@zhangjiashen
zhangjiashen committed Oct 25, 2023
1 parent 1ca3212 commit e3738f8
Show file tree
Hide file tree
Showing 2 changed files with 68 additions and 69 deletions.
13 changes: 6 additions & 7 deletions parquet-column/src/main/java/org/apache/parquet/column/statistics/Statistics.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -142,6 +142,9 @@ public Statistics<?> build() {

// Builder for FLOAT16 type to handle special cases of min/max values like NaN, -0.0, and 0.0
private static class Float16Builder extends Builder {
private final static Binary POSITIVE_ZERO_LITTLE_ENDIAN = Binary.fromConstantByteArray(new byte[] {0x00, 0x00});
private final static Binary NEGATIVE_ZERO_LITTLE_ENDIAN = Binary.fromConstantByteArray(new byte[] {0x00, (byte) 0x80});

public Float16Builder(PrimitiveType type) {
super(type);
assert type.getPrimitiveTypeName() == PrimitiveTypeName.FIXED_LEN_BYTE_ARRAY;
Expand All @@ -158,19 +161,15 @@ public Statistics<?> build() {
short max = bMax.get2BytesLittleEndian();
// Drop min/max values in case of NaN as the sorting order of values is undefined for this case
if (Float16.isNaN(min) || Float16.isNaN(max)) {
bMin = Binary.fromConstantByteArray(new byte[] {0x00, 0x00});
bMax = Binary.fromConstantByteArray(new byte[] {0x00, (byte) 0x80});
stats.setMinMax(bMin, bMax);
stats.setMinMax(POSITIVE_ZERO_LITTLE_ENDIAN, NEGATIVE_ZERO_LITTLE_ENDIAN);
((Statistics<?>) stats).hasNonNullValue = false;
} else {
// Updating min to -0.0 and max to +0.0 to ensure that no 0.0 values would be skipped
if (min == (short) 0x0000) {
bMin = Binary.fromConstantByteArray(new byte[] {0x00, (byte) 0x80});
stats.setMinMax(bMin, bMax);
stats.setMinMax(NEGATIVE_ZERO_LITTLE_ENDIAN, bMax);
}
if (max == (short) 0x8000) {
bMax = Binary.fromConstantByteArray(new byte[] {0x00, 0x00});
stats.setMinMax(bMin, bMax);
stats.setMinMax(bMin, POSITIVE_ZERO_LITTLE_ENDIAN);
}
}
}
Expand Down
124 changes: 62 additions & 62 deletions parquet-column/src/main/java/org/apache/parquet/schema/Float16.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -74,6 +74,65 @@ public class Float16 {
private static final int FP32_DENORMAL_MAGIC = 126 << 23;
private static final float FP32_DENORMAL_FLOAT = Float.intBitsToFloat(FP32_DENORMAL_MAGIC);

/**
* Returns true if the specified half-precision float value represents
* a Not-a-Number, false otherwise.
*
* @param h A half-precision float value
* @return True if the value is a NaN, false otherwise
*
*/
public static boolean isNaN(short h) {
return (h & EXPONENT_SIGNIFICAND_MASK) > POSITIVE_INFINITY;
}

/**
* <p>Compares the two specified half-precision float values. The following
* conditions apply during the comparison:</p>
*
* <ul>
* <li>NaN is considered by this method to be equal to itself and greater
* than all other half-precision float values (including {@code #POSITIVE_INFINITY})</li>
* <li>POSITIVE_ZERO is considered by this method to be greater than NEGATIVE_ZERO.</li>
* </ul>
*
* @param x The first half-precision float value to compare.
* @param y The second half-precision float value to compare
*
* @return The value {@code 0} if {@code x} is numerically equal to {@code y}, a
* value less than {@code 0} if {@code x} is numerically less than {@code y},
* and a value greater than {@code 0} if {@code x} is numerically greater
* than {@code y}
*
*/
public static int compare(short x, short y) {
boolean xIsNaN = isNaN(x);
boolean yIsNaN = isNaN(y);

if (!xIsNaN && !yIsNaN) {
int first = ((x & SIGN_MASK) != 0 ? 0x8000 - (x & 0xffff) : x & 0xffff);
int second = ((y & SIGN_MASK) != 0 ? 0x8000 - (y & 0xffff) : y & 0xffff);
// Returns true if the first half-precision float value is less
// (smaller toward negative infinity) than the second half-precision float value.
if (first < second) {
return -1;
}

// Returns true if the first half-precision float value is greater
// (larger toward positive infinity) than the second half-precision float value.
if (first > second) {
return 1;
}
}

// Collapse NaNs, akin to halfToIntBits(), but we want to keep
// (signed) short value types to preserve the ordering of -0.0
// and +0.0
short xBits = xIsNaN ? NaN : x;
short yBits = yIsNaN ? NaN : y;
return (xBits == yBits ? 0 : (xBits < yBits ? -1 : 1));
}

/**
* Converts the specified half-precision float value in Binary little endian into a
* single-precision float value. The following special cases are handled:
Expand All @@ -86,7 +145,7 @@ public class Float16 {
* @param b The half-precision float value in Binary little endian to convert to single-precision
* @return A normalized single-precision float value
*/
public static float toFloat(Binary b) {
static float toFloat(Binary b) {
short h = b.get2BytesLittleEndian();
int bits = h & 0xffff;
int s = bits & SIGN_MASK;
Expand Down Expand Up @@ -135,7 +194,7 @@ public static float toFloat(Binary b) {
* @param f The single-precision float value to convert to half-precision
* @return A half-precision float value
*/
public static short toFloat16(float f) {
static short toFloat16(float f) {
int bits = Float.floatToRawIntBits(f);
int s = (bits >>> FP32_SIGN_SHIFT );
int e = (bits >>> FP32_EXPONENT_SHIFT) & FP32_SHIFTED_EXPONENT_MASK;
Expand Down Expand Up @@ -185,65 +244,6 @@ public static short toFloat16(float f) {
return (short) ((s << SIGN_SHIFT) | (outE << EXPONENT_SHIFT) + outM);
}

/**
* Returns true if the specified half-precision float value represents
* a Not-a-Number, false otherwise.
*
* @param h A half-precision float value
* @return True if the value is a NaN, false otherwise
*
*/
public static boolean isNaN(short h) {
return (h & EXPONENT_SIGNIFICAND_MASK) > POSITIVE_INFINITY;
}

/**
* <p>Compares the two specified half-precision float values. The following
* conditions apply during the comparison:</p>
*
* <ul>
* <li>NaN is considered by this method to be equal to itself and greater
* than all other half-precision float values (including {@code #POSITIVE_INFINITY})</li>
* <li>POSITIVE_ZERO is considered by this method to be greater than NEGATIVE_ZERO.</li>
* </ul>
*
* @param x The first half-precision float value to compare.
* @param y The second half-precision float value to compare
*
* @return The value {@code 0} if {@code x} is numerically equal to {@code y}, a
* value less than {@code 0} if {@code x} is numerically less than {@code y},
* and a value greater than {@code 0} if {@code x} is numerically greater
* than {@code y}
*
*/
public static int compare(short x, short y) {
boolean xIsNaN = isNaN(x);
boolean yIsNaN = isNaN(y);

if (!xIsNaN && !yIsNaN) {
int first = ((x & SIGN_MASK) != 0 ? 0x8000 - (x & 0xffff) : x & 0xffff);
int second = ((y & SIGN_MASK) != 0 ? 0x8000 - (y & 0xffff) : y & 0xffff);
// Returns true if the first half-precision float value is less
// (smaller toward negative infinity) than the second half-precision float value.
if (first < second) {
return -1;
}

// Returns true if the first half-precision float value is greater
// (larger toward positive infinity) than the second half-precision float value.
if (first > second) {
return 1;
}
}

// Collapse NaNs, akin to halfToIntBits(), but we want to keep
// (signed) short value types to preserve the ordering of -0.0
// and +0.0
short xBits = xIsNaN ? NaN : x;
short yBits = yIsNaN ? NaN : y;
return (xBits == yBits ? 0 : (xBits < yBits ? -1 : 1));
}

/**
* Returns a string representation of the specified half-precision
* float value. Calling this method is equivalent to calling
Expand All @@ -253,7 +253,7 @@ public static int compare(short x, short y) {
* @param h A half-precision float value in binary little-endian format
* @return A string representation of the specified value
*/
public static String toFloatString(Binary h) {
static String toFloatString(Binary h) {
return Float.toString(Float16.toFloat(h));
}
}

0 comments on commit e3738f8

Please sign in to comment.