1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.util;
18
19import static com.android.internal.util.Preconditions.checkNotNull;
20
21/**
22 * Immutable class for describing width and height dimensions in pixels.
23 */
24public final class Size {
25    /**
26     * Create a new immutable Size instance.
27     *
28     * @param width The width of the size, in pixels
29     * @param height The height of the size, in pixels
30     */
31    public Size(int width, int height) {
32        mWidth = width;
33        mHeight = height;
34    }
35
36    /**
37     * Get the width of the size (in pixels).
38     * @return width
39     */
40    public int getWidth() {
41        return mWidth;
42    }
43
44    /**
45     * Get the height of the size (in pixels).
46     * @return height
47     */
48    public int getHeight() {
49        return mHeight;
50    }
51
52    /**
53     * Check if this size is equal to another size.
54     * <p>
55     * Two sizes are equal if and only if both their widths and heights are
56     * equal.
57     * </p>
58     * <p>
59     * A size object is never equal to any other type of object.
60     * </p>
61     *
62     * @return {@code true} if the objects were equal, {@code false} otherwise
63     */
64    @Override
65    public boolean equals(final Object obj) {
66        if (obj == null) {
67            return false;
68        }
69        if (this == obj) {
70            return true;
71        }
72        if (obj instanceof Size) {
73            Size other = (Size) obj;
74            return mWidth == other.mWidth && mHeight == other.mHeight;
75        }
76        return false;
77    }
78
79    /**
80     * Return the size represented as a string with the format {@code "WxH"}
81     *
82     * @return string representation of the size
83     */
84    @Override
85    public String toString() {
86        return mWidth + "x" + mHeight;
87    }
88
89    private static NumberFormatException invalidSize(String s) {
90        throw new NumberFormatException("Invalid Size: \"" + s + "\"");
91    }
92
93    /**
94     * Parses the specified string as a size value.
95     * <p>
96     * The ASCII characters {@code \}{@code u002a} ('*') and
97     * {@code \}{@code u0078} ('x') are recognized as separators between
98     * the width and height.</p>
99     * <p>
100     * For any {@code Size s}: {@code Size.parseSize(s.toString()).equals(s)}.
101     * However, the method also handles sizes expressed in the
102     * following forms:</p>
103     * <p>
104     * "<i>width</i>{@code x}<i>height</i>" or
105     * "<i>width</i>{@code *}<i>height</i>" {@code => new Size(width, height)},
106     * where <i>width</i> and <i>height</i> are string integers potentially
107     * containing a sign, such as "-10", "+7" or "5".</p>
108     *
109     * <pre>{@code
110     * Size.parseSize("3*+6").equals(new Size(3, 6)) == true
111     * Size.parseSize("-3x-6").equals(new Size(-3, -6)) == true
112     * Size.parseSize("4 by 3") => throws NumberFormatException
113     * }</pre>
114     *
115     * @param string the string representation of a size value.
116     * @return the size value represented by {@code string}.
117     *
118     * @throws NumberFormatException if {@code string} cannot be parsed
119     * as a size value.
120     * @throws NullPointerException if {@code string} was {@code null}
121     */
122    public static Size parseSize(String string)
123            throws NumberFormatException {
124        checkNotNull(string, "string must not be null");
125
126        int sep_ix = string.indexOf('*');
127        if (sep_ix < 0) {
128            sep_ix = string.indexOf('x');
129        }
130        if (sep_ix < 0) {
131            throw invalidSize(string);
132        }
133        try {
134            return new Size(Integer.parseInt(string.substring(0, sep_ix)),
135                    Integer.parseInt(string.substring(sep_ix + 1)));
136        } catch (NumberFormatException e) {
137            throw invalidSize(string);
138        }
139    }
140
141    /**
142     * {@inheritDoc}
143     */
144    @Override
145    public int hashCode() {
146        // assuming most sizes are <2^16, doing a rotate will give us perfect hashing
147        return mHeight ^ ((mWidth << (Integer.SIZE / 2)) | (mWidth >>> (Integer.SIZE / 2)));
148    }
149
150    private final int mWidth;
151    private final int mHeight;
152}
153