Java String Pad Left leftPad(String s, int z)

Description

Left pad a String with spaces.

License

Open Source License

Parameter

Parameter	Description
s	The String to pad out
z	The size to pad to

Return

The left padded String

Declaration

public static String leftPad(String s, int z) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

public class Main {
    /**/*from  w  ww.j  a v a 2s  .  co  m*/
     * Left pad a String with spaces. Pad to a size of n.
     * 
     * @param s
     *            The String to pad out
     * @param z
     *            The size to pad to
     * @return The left padded String
     */
    public static String leftPad(String s, int z) {
        return leftPad(s, z, " ");
    }

    /**
     * Left pad a String with a specified string. Pad to a size of n.
     * 
     * @param s
     *            The String to pad out
     * @param z
     *            The size to pad to
     * @param d
     *            String to pad with
     * @return left padded String
     */
    public static String leftPad(String s, int z, String d) {
        z = (z - s.length()) / d.length();
        if (z > 0)
            s = repeat(d, z) + s;
        return s;
    }

    /**
     * Repeat a string n times to form a new string.
     * 
     * @param s
     *            String to repeat
     * @param t
     *            The times of the string to repeat
     * @return The new string after repeat
     */
    public static String repeat(String s, int t) {
        StringBuffer buffer = new StringBuffer(t * s.length());

        for (int i = 0; i < t; i++)
            buffer.append(s);

        return buffer.toString();
    }

    public static String toString(int[] codePoints, int offset, int count) {
        if (offset < 0) {
            throw new StringIndexOutOfBoundsException(offset);
        }
        if (count < 0) {
            throw new StringIndexOutOfBoundsException(count);
        }
        // Note: offset or count might be near -1>>>1.
        if (offset > codePoints.length - count) {
            throw new StringIndexOutOfBoundsException(offset + count);
        }

        int expansion = 0;
        int margin = 1;
        char[] v = new char[count + margin];
        int x = offset;
        int j = 0;
        for (int i = 0; i < count; i++) {
            int c = codePoints[x++];
            if (c < 0) {
                throw new IllegalArgumentException();
            }
            if (margin <= 0 && (j + 1) >= v.length) {
                if (expansion == 0) {
                    expansion = (((-margin + 1) * count) << 10) / i;
                    expansion >>= 10;
                    if (expansion <= 0) {
                        expansion = 1;
                    }
                } else {
                    expansion *= 2;
                }
                int newLen = Math.min(v.length + expansion, count * 2);
                margin = (newLen - v.length) - (count - i);

                char[] copy = new char[newLen];
                System.arraycopy(v, 0, copy, 0, Math.min(v.length, newLen));
                v = copy;
            }
            if (c < 0x010000) {
                v[j++] = (char) c;
            } else if (c <= 0x10ffff) {

                // Character.toSurrogates(c, v, j);
                int charOffset = c - 0x010000;
                v[j + 1] = (char) ((charOffset & 0x3ff) + '\uDC00');
                v[j] = (char) ((charOffset >>> 10) + '\uD800');

                j += 2;
                margin--;
            } else {
                throw new IllegalArgumentException();
            }
        }

        return new String(v, 0, j);
    }
}

Related

1. leftPad(String s, int length)
2. leftPad(String s, int minLength)
3. leftPad(String s, int n)
4. leftPad(String s, int target)
5. leftPad(String s, int width)
6. leftPad(String srcStr, char padChar, int destLen)
7. leftPad(String srcString, char c, int length)
8. leftPad(String srcString, char c, int length)
9. leftPad(String str, int len, char c)