Examples with LiteralParameters io.prestosql.spi.function.LiteralParameters used on opensource projects

Example 11 with LiteralParameters

use of io.prestosql.spi.function.LiteralParameters in project hetu-core by openlookeng.

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 12 with LiteralParameters

use of io.prestosql.spi.function.LiteralParameters in project hetu-core by openlookeng.

the class StringFunctions method substr.

@Description("substring of given length starting at an index")
@ScalarFunction
@LiteralParameters("x")
@SqlType("varchar(x)")
public static Slice substr(@SqlType("varchar(x)") Slice utf8, @SqlType(StandardTypes.BIGINT) long start, @SqlType(StandardTypes.BIGINT) long length) {
    if (start == 0 || (length <= 0) || (utf8.length() == 0)) {
        return Slices.EMPTY_SLICE;
    }
    int startCodePoint = Ints.saturatedCast(start);
    int lengthCodePoints = Ints.saturatedCast(length);
    if (startCodePoint > 0) {
        int indexStart = offsetOfCodePoint(utf8, startCodePoint - 1);
        if (indexStart < 0) {
            // before beginning of string
            return Slices.EMPTY_SLICE;
        }
        int indexEnd = offsetOfCodePoint(utf8, indexStart, lengthCodePoints);
        if (indexEnd < 0) {
            // after end of string
            indexEnd = utf8.length();
        }
        return utf8.slice(indexStart, indexEnd - indexStart);
    }
    // negative start is relative to end of string
    int codePoints = countCodePoints(utf8);
    startCodePoint += codePoints;
    // before beginning of string
    if (startCodePoint < 0) {
        return Slices.EMPTY_SLICE;
    }
    int indexStart = offsetOfCodePoint(utf8, startCodePoint);
    int indexEnd;
    if (startCodePoint + lengthCodePoints < codePoints) {
        indexEnd = offsetOfCodePoint(utf8, indexStart, lengthCodePoints);
    } else {
        indexEnd = utf8.length();
    }
    return utf8.slice(indexStart, indexEnd - indexStart);
}

Example 13 with LiteralParameters

use of io.prestosql.spi.function.LiteralParameters in project hetu-core by openlookeng.

the class StringFunctions method fromUtf8.

@Description("decodes the UTF-8 encoded string")
@ScalarFunction
@LiteralParameters("x")
@SqlType(StandardTypes.VARCHAR)
public static Slice fromUtf8(@SqlType(StandardTypes.VARBINARY) Slice slice, @SqlType("varchar(x)") Slice replacementCharacter) {
    int count = countCodePoints(replacementCharacter);
    if (count > 1) {
        throw new PrestoException(INVALID_FUNCTION_ARGUMENT, "Replacement character string must empty or a single character");
    }
    OptionalInt replacementCodePoint;
    if (count == 1) {
        try {
            replacementCodePoint = OptionalInt.of(getCodePointAt(replacementCharacter, 0));
        } catch (InvalidUtf8Exception e) {
            throw new PrestoException(INVALID_FUNCTION_ARGUMENT, "Invalid replacement character");
        }
    } else {
        replacementCodePoint = OptionalInt.empty();
    }
    return SliceUtf8.fixInvalidUtf8(slice, replacementCodePoint);
}

Example 14 with LiteralParameters

use of io.prestosql.spi.function.LiteralParameters in project hetu-core by openlookeng.

the class StringFunctions method concat.

// TODO: implement N arguments char concat
@Description("concatenates given character strings")
@ScalarFunction
@LiteralParameters({ "x", "y", "u" })
@Constraint(variable = "u", expression = "x + y")
@SqlType("char(u)")
public static Slice concat(@LiteralParameter("x") Long x, @SqlType("char(x)") Slice left, @SqlType("char(y)") Slice right) {
    int rightLength = right.length();
    if (rightLength == 0) {
        return left;
    }
    Slice paddedLeft = padSpaces(left, x.intValue());
    int leftLength = paddedLeft.length();
    Slice result = Slices.allocate(leftLength + rightLength);
    result.setBytes(0, paddedLeft);
    result.setBytes(leftLength, right);
    return result;
}

Example 15 with LiteralParameters

use of io.prestosql.spi.function.LiteralParameters in project hetu-core by openlookeng.

the class StringFunctions method hammingDistance.

@Description("computes Hamming distance between two strings")
@ScalarFunction
@LiteralParameters({ "x", "y" })
@SqlType(StandardTypes.BIGINT)
public static long hammingDistance(@SqlType("varchar(x)") Slice left, @SqlType("varchar(y)") Slice right) {
    int distance = 0;
    int leftPosition = 0;
    int rightPosition = 0;
    while (leftPosition < left.length() && rightPosition < right.length()) {
        int codePointLeft = tryGetCodePointAt(left, leftPosition);
        int codePointRight = tryGetCodePointAt(right, rightPosition);
        // the following code treats them as equal if they happen to be of the same length
        if (codePointLeft != codePointRight) {
            distance++;
        }
        leftPosition += codePointLeft > 0 ? lengthOfCodePoint(codePointLeft) : -codePointLeft;
        rightPosition += codePointRight > 0 ? lengthOfCodePoint(codePointRight) : -codePointRight;
    }
    checkCondition(leftPosition == left.length() && rightPosition == right.length(), INVALID_FUNCTION_ARGUMENT, "The input strings to hamming_distance function must have the same length");
    return distance;
}