Examples with Description com.facebook.presto.spi.function.Description used on opensource projects

Example 61 with Description

use of com.facebook.presto.spi.function.Description in project presto by prestodb.

the class StringFunctions method levenshteinDistance.

@Description("computes Levenshtein distance between two strings")
@ScalarFunction
@LiteralParameters({ "x", "y" })
@SqlType(StandardTypes.BIGINT)
public static long levenshteinDistance(@SqlType("varchar(x)") Slice left, @SqlType("varchar(y)") Slice right) {
    int[] leftCodePoints = castToCodePoints(left);
    int[] rightCodePoints = castToCodePoints(right);
    if (leftCodePoints.length < rightCodePoints.length) {
        int[] tempCodePoints = leftCodePoints;
        leftCodePoints = rightCodePoints;
        rightCodePoints = tempCodePoints;
    }
    if (rightCodePoints.length == 0) {
        return leftCodePoints.length;
    }
    checkCondition((leftCodePoints.length * (rightCodePoints.length - 1)) <= 1_000_000, INVALID_FUNCTION_ARGUMENT, "The combined inputs for Levenshtein distance are too large");
    int[] distances = new int[rightCodePoints.length];
    for (int i = 0; i < rightCodePoints.length; i++) {
        distances[i] = i + 1;
    }
    for (int i = 0; i < leftCodePoints.length; i++) {
        int leftUpDistance = distances[0];
        if (leftCodePoints[i] == rightCodePoints[0]) {
            distances[0] = i;
        } else {
            distances[0] = Math.min(i, distances[0]) + 1;
        }
        for (int j = 1; j < rightCodePoints.length; j++) {
            int leftUpDistanceNext = distances[j];
            if (leftCodePoints[i] == rightCodePoints[j]) {
                distances[j] = leftUpDistance;
            } else {
                distances[j] = Math.min(distances[j - 1], Math.min(leftUpDistance, distances[j])) + 1;
            }
            leftUpDistance = leftUpDistanceNext;
        }
    }
    return distances[rightCodePoints.length - 1];
}

Example 62 with Description

use of com.facebook.presto.spi.function.Description in project presto by prestodb.

the class VarbinaryFunctions method xxhash64.

@Description("compute xxhash64 hash")
@ScalarFunction
@SqlType(StandardTypes.VARBINARY)
public static Slice xxhash64(@SqlType(StandardTypes.VARBINARY) Slice slice) {
    Slice hash = Slices.allocate(Long.BYTES);
    hash.setLong(0, Long.reverseBytes(XxHash64.hash(slice)));
    return hash;
}

Example 63 with Description

use of com.facebook.presto.spi.function.Description in project presto by prestodb.

the class VarbinaryFunctions method toIEEE754Binary64.

@Description("encode value as a big endian varbinary according to IEEE 754 double-precision floating-point format")
@ScalarFunction("to_ieee754_64")
@SqlType(StandardTypes.VARBINARY)
public static Slice toIEEE754Binary64(@SqlType(StandardTypes.DOUBLE) double value) {
    Slice slice = Slices.allocate(Double.BYTES);
    slice.setLong(0, Long.reverseBytes(Double.doubleToLongBits(value)));
    return slice;
}

Example 64 with Description

use of com.facebook.presto.spi.function.Description in project presto by prestodb.

the class VarbinaryFunctions method toIEEE754Binary32.

@Description("encode value as a big endian varbinary according to IEEE 754 single-precision floating-point format")
@ScalarFunction("to_ieee754_32")
@SqlType(StandardTypes.VARBINARY)
public static Slice toIEEE754Binary32(@SqlType(StandardTypes.REAL) long value) {
    Slice slice = Slices.allocate(Float.BYTES);
    slice.setInt(0, Integer.reverseBytes((int) value));
    return slice;
}

Example 65 with Description

use of com.facebook.presto.spi.function.Description in project presto by prestodb.

the class VarbinaryFunctions method toBigEndian32.

@Description("encode value as a 32-bit 2's complement big endian varbinary")
@ScalarFunction("to_big_endian_32")
@SqlType(StandardTypes.VARBINARY)
public static Slice toBigEndian32(@SqlType(StandardTypes.INTEGER) long value) {
    Slice slice = Slices.allocate(Integer.BYTES);
    slice.setInt(0, Integer.reverseBytes((int) value));
    return slice;
}