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      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 
     17 package com.android.gallery3d.common;
     18 
     19 import android.database.Cursor;
     20 import android.graphics.RectF;
     21 import android.os.ParcelFileDescriptor;
     22 import android.util.Log;
     23 
     24 import java.io.Closeable;
     25 import java.io.IOException;
     26 
     27 public 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