NumberUtils.java

package org.compass.core.converter.basic.format;

/**
 * @author kimchy
 */
// TAKEN FROM SOLR, thanks!
public class NumberUtils {

    public static String int2sortableStr(int val) {
        char[] arr = new char[3];
        int2sortableStr(val, arr, 0);
        return new String(arr, 0, 3);
    }

    public static String int2sortableStr(String val) {
        return int2sortableStr(Integer.parseInt(val));
    }

    public static int SortableStr2int(String val) {
        return SortableStr2int(val, 0, 3);
    }

    public static String long2sortableStr(long val) {
        char[] arr = new char[5];
        long2sortableStr(val, arr, 0);
        return new String(arr, 0, 5);
    }

    public static String long2sortableStr(String val) {
        return long2sortableStr(Long.parseLong(val));
    }

    public static long SortableStr2long(String val) {
        return SortableStr2long(val, 0, 5);
    }

    //
    // IEEE floating point format is defined so that it sorts correctly
    // when interpreted as a signed integer (or signed long in the case
    // of a double) for positive values.  For negative values, all the bits except
    // the sign bit must be inverted.
    // This correctly handles all possible float values including -Infinity and +Infinity.
    // Note that in float-space, NaN<x is false, NaN>x is false, NaN==x is false, NaN!=x is true
    // for all x (including NaN itself).  Internal to Solr, NaN==NaN is true and NaN
    // sorts higher than Infinity, so a range query of [-Infinity TO +Infinity] will
    // exclude NaN values, but a query of "NaN" will find all NaN values.
    // Also, -0==0 in float-space but -0<0 after this transformation.
    //
    public static String float2sortableStr(float val) {
        int f = Float.floatToRawIntBits(val);
        if (f < 0) f ^= 0x7fffffff;
        return int2sortableStr(f);
    }

    public static String float2sortableStr(String val) {
        return float2sortableStr(Float.parseFloat(val));
    }

    public static float SortableStr2float(String val) {
        int f = SortableStr2int(val, 0, 3);
        if (f < 0) f ^= 0x7fffffff;
        return Float.intBitsToFloat(f);
    }

    public static String SortableStr2floatStr(String val) {
        return Float.toString(SortableStr2float(val));
    }


    public static String double2sortableStr(double val) {
        long f = Double.doubleToRawLongBits(val);
        if (f < 0) f ^= 0x7fffffffffffffffL;
        return long2sortableStr(f);
    }

    public static String double2sortableStr(String val) {
        return double2sortableStr(Double.parseDouble(val));
    }

    public static double SortableStr2double(String val) {
        long f = SortableStr2long(val, 0, 6);
        if (f < 0) f ^= 0x7fffffffffffffffL;
        return Double.longBitsToDouble(f);
    }

    public static String SortableStr2doubleStr(String val) {
        return Double.toString(SortableStr2double(val));
    }


    // uses binary representation of an int to build a string of
    // chars that will sort correctly.  Only char ranges
    // less than 0xd800 will be used to avoid UCS-16 surrogates.
    public static int int2sortableStr(int val, char[] out, int offset) {
        val += Integer.MIN_VALUE;
        out[offset++] = (char) (val >>> 24);
        out[offset++] = (char) ((val >>> 12) & 0x0fff);
        out[offset++] = (char) (val & 0x0fff);
        return 3;
    }

    public static int SortableStr2int(String sval, int offset, int len) {
        int val = sval.charAt(offset++) << 24;
        val |= sval.charAt(offset++) << 12;
        val |= sval.charAt(offset++);
        val -= Integer.MIN_VALUE;
        return val;
    }

    // uses binary representation of an int to build a string of
    // chars that will sort correctly.  Only char ranges
    // less than 0xd800 will be used to avoid UCS-16 surrogates.
    // we can use the lowest 15 bits of a char, (or a mask of 0x7fff)
    public static int long2sortableStr(long val, char[] out, int offset) {
        val += Long.MIN_VALUE;
        out[offset++] = (char) (val >>> 60);
        out[offset++] = (char) (val >>> 45 & 0x7fff);
        out[offset++] = (char) (val >>> 30 & 0x7fff);
        out[offset++] = (char) (val >>> 15 & 0x7fff);
        out[offset] = (char) (val & 0x7fff);
        return 5;
    }

    public static long SortableStr2long(String sval, int offset, int len) {
        long val = (long) (sval.charAt(offset++)) << 60;
        val |= ((long) sval.charAt(offset++)) << 45;
        val |= ((long) sval.charAt(offset++)) << 30;
        val |= sval.charAt(offset++) << 15;
        val |= sval.charAt(offset);
        val -= Long.MIN_VALUE;
        return val;
    }

}