1/*
2 * Copyright (C) 2010 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 com.android.gallery3d.common;
18
19import android.database.Cursor;
20import android.graphics.RectF;
21import android.os.ParcelFileDescriptor;
22import android.util.Log;
23
24import java.io.Closeable;
25import java.io.IOException;
26
27public class Utils {
28    private static final String TAG = "Utils";
29
30    // Throws AssertionError if the input is false.
31    public static void assertTrue(boolean cond) {
32        if (!cond) {
33            throw new AssertionError();
34        }
35    }
36
37    // Returns the next power of two.
38    // Returns the input if it is already power of 2.
39    // Throws IllegalArgumentException if the input is <= 0 or
40    // the answer overflows.
41    public static int nextPowerOf2(int n) {
42        if (n <= 0 || n > (1 << 30)) throw new IllegalArgumentException("n is invalid: " + n);
43        n -= 1;
44        n |= n >> 16;
45        n |= n >> 8;
46        n |= n >> 4;
47        n |= n >> 2;
48        n |= n >> 1;
49        return n + 1;
50    }
51
52    // Returns the previous power of two.
53    // Returns the input if it is already power of 2.
54    // Throws IllegalArgumentException if the input is <= 0
55    public static int prevPowerOf2(int n) {
56        if (n <= 0) throw new IllegalArgumentException();
57        return Integer.highestOneBit(n);
58    }
59
60    // Returns the input value x clamped to the range [min, max].
61    public static int clamp(int x, int min, int max) {
62        if (x > max) return max;
63        if (x < min) return min;
64        return x;
65    }
66
67    public static int ceilLog2(float value) {
68        int i;
69        for (i = 0; i < 31; i++) {
70            if ((1 << i) >= value) break;
71        }
72        return i;
73    }
74
75    public static int floorLog2(float value) {
76        int i;
77        for (i = 0; i < 31; i++) {
78            if ((1 << i) > value) break;
79        }
80        return i - 1;
81    }
82
83    public static void closeSilently(Closeable c) {
84        if (c == null) return;
85        try {
86            c.close();
87        } catch (IOException t) {
88            Log.w(TAG, "close fail ", t);
89        }
90    }
91
92    public static void closeSilently(ParcelFileDescriptor fd) {
93        try {
94            if (fd != null) fd.close();
95        } catch (Throwable t) {
96            Log.w(TAG, "fail to close", t);
97        }
98    }
99
100    public static void closeSilently(Cursor cursor) {
101        try {
102            if (cursor != null) cursor.close();
103        } catch (Throwable t) {
104            Log.w(TAG, "fail to close", t);
105        }
106    }
107
108    public static RectF getMaxCropRect(
109            int inWidth, int inHeight, int outWidth, int outHeight, boolean leftAligned) {
110        RectF cropRect = new RectF();
111        // Get a crop rect that will fit this
112        if (inWidth / (float) inHeight > outWidth / (float) outHeight) {
113             cropRect.top = 0;
114             cropRect.bottom = inHeight;
115             cropRect.left = (inWidth - (outWidth / (float) outHeight) * inHeight) / 2;
116             cropRect.right = inWidth - cropRect.left;
117             if (leftAligned) {
118                 cropRect.right -= cropRect.left;
119                 cropRect.left = 0;
120             }
121        } else {
122            cropRect.left = 0;
123            cropRect.right = inWidth;
124            cropRect.top = (inHeight - (outHeight / (float) outWidth) * inWidth) / 2;
125            cropRect.bottom = inHeight - cropRect.top;
126        }
127        return cropRect;
128    }
129
130    /**
131     * Find the min x that 1 / x >= scale
132     */
133    public static int computeSampleSizeLarger(float scale) {
134        int initialSize = (int) Math.floor(1f / scale);
135        if (initialSize <= 1) return 1;
136        return initialSize <= 8 ? prevPowerOf2(initialSize) : (initialSize / 8 * 8);
137    }
138}
139