package ij.util;
import java.awt.Color;
import java.util.*;
import java.io.*;

/** This class contains static utility methods. */
 public class Tools {
    /** This array contains the 16 hex digits '0'-'F'. */
    public static final char[] hexDigits = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
    
    /** Converts a Color to an 7 byte hex string starting with '#'. */
    public static String c2hex(Color c) {
        int i = c.getRGB();
        char[] buf7 = new char[7];
        buf7[0] = '#';
        for (int pos=6; pos>=1; pos--) {
            buf7[pos] = hexDigits[i&0xf];
            i >>>= 4;
        }
        return new String(buf7);
    }
        
    /** Converts a float to an 9 byte hex string starting with '#'. */
    public static String f2hex(float f) {
        int i = Float.floatToIntBits(f);
        char[] buf9 = new char[9];
        buf9[0] = '#';
        for (int pos=8; pos>=1; pos--) {
            buf9[pos] = hexDigits[i&0xf];
            i >>>= 4;
        }
        return new String(buf9);
    }
        
    public static double[] getMinMax(double[] a) {
        double min = Double.MAX_VALUE;
        double max = -Double.MAX_VALUE;
        double value;
        for (int i=0; i<a.length; i++) {
            value = a[i];
            if (value<min)
                min = value;
            if (value>max)
                max = value;
        }
        double[] minAndMax = new double[2];
        minAndMax[0] = min;
        minAndMax[1] = max;
        return minAndMax;
    }

    public static double[] getMinMax(float[] a) {
        double min = Double.MAX_VALUE;
        double max = -Double.MAX_VALUE;
        double value;
        for (int i=0; i<a.length; i++) {
            value = a[i];
            if (value<min)
                min = value;
            if (value>max)
                max = value;
        }
        double[] minAndMax = new double[2];
        minAndMax[0] = min;
        minAndMax[1] = max;
        return minAndMax;
    }
    
    /** Converts the float array 'a' to a double array. */
    public static double[] toDouble(float[] a) {
        int len = a.length;
        double[] d = new double[len];
        for (int i=0; i<len; i++)
            d[i] = a[i];
        return d;
    }
    
    /** Converts the double array 'a' to a float array. */
    public static float[] toFloat(double[] a) {
        int len = a.length;
        float[] f = new float[len];
        for (int i=0; i<len; i++)
            f[i] = (float)a[i];
        return f;
    }
    
    /** Converts carriage returns to line feeds. */
    public static String fixNewLines(String s) {
        char[] chars = s.toCharArray();
        for (int i=0; i<chars.length; i++)
            {if (chars[i]=='\r') chars[i] = '\n';}
        return new String(chars);
    }

    /**
    * Returns a double containg the value represented by the 
    * specified <code>String</code>.
    *
    * @param      s   the string to be parsed.
    * @param      defaultValue   the value returned if <code>s</code>
    *   does not contain a parsable double
    * @return     The double value represented by the string argument or
    *   <code>defaultValue</code> if the string does not contain a parsable double
    */
    public static double parseDouble(String s, double defaultValue) {
        if (s==null) return defaultValue;
        try {
            defaultValue = Double.parseDouble(s);
        } catch (NumberFormatException e) {}
        return defaultValue;            
    }

    /**
    * Returns a double containg the value represented by the 
    * specified <code>String</code>.
    *
    * @param      s   the string to be parsed.
    * @return     The double value represented by the string argument or
    *   Double.NaN if the string does not contain a parsable double
    */
    public static double parseDouble(String s) {
        return parseDouble(s, Double.NaN);
    }
    
    /** Returns the number of decimal places need to display two numbers. */
    public static int getDecimalPlaces(double n1, double n2) {
        if (Math.round(n1)==n1 && Math.round(n2)==n2)
            return 0;
        else {
            n1 = Math.abs(n1);
            n2 = Math.abs(n2);
            double n = n1<n2&&n1>0.0?n1:n2;
            double diff = Math.abs(n2-n1);
            if (diff>0.0 && diff<n) n = diff;           
            int digits = 2;
            if (n<100.0) digits = 3;
            if (n<0.1) digits = 4;
            if (n<0.01) digits = 5;
            if (n<0.001) digits = 6;
            if (n<0.0001) digits = 7;
            return digits;
        }
    }
    
    /** Splits a string into substrings using the default delimiter set, 
    which is " \t\n\r" (space, tab, newline and carriage-return). */
    public static String[] split(String str) {
        return split(str, " \t\n\r");
    }

    /** Splits a string into substring using the characters
    contained in the second argument as the delimiter set. */
    public static String[] split(String str, String delim) {
        if (delim.equals("\n"))
            return splitLines(str);
        StringTokenizer t = new StringTokenizer(str, delim);
        int tokens = t.countTokens();
        String[] strings;
        if (tokens>0) {
            strings = new String[tokens];
            for(int i=0; i<tokens; i++) 
                strings[i] = t.nextToken();
        } else {
            strings = new String[1];
            strings[0] = str;
            tokens = 1;
        }
        return strings;
    }
    
    static String[] splitLines(String str) {
        Vector v = new Vector();
        try {
            BufferedReader br  = new BufferedReader(new StringReader(str));
            String line;
            while (true) {
                line = br.readLine();
                if (line == null) break;
                v.addElement(line);
            }
            br.close();
        } catch(Exception e) { }
        String[] lines = new String[v.size()];
        v.copyInto((String[])lines);
        return lines;
    }
    
}