/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.gallery3d.common;

import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager.NameNotFoundException;
import android.database.Cursor;
import android.os.Build;
import android.os.ParcelFileDescriptor;
import android.text.TextUtils;
import android.util.Log;

import java.io.Closeable;
import java.io.IOException;
import java.io.InterruptedIOException;

public class Utils {
    private static final String TAG = "Utils";
    private static final String DEBUG_TAG = "GalleryDebug";

    private static final long POLY64REV = 0x95AC9329AC4BC9B5L;
    private static final long INITIALCRC = 0xFFFFFFFFFFFFFFFFL;

    private static long[] sCrcTable = new long[256];

    private static final boolean IS_DEBUG_BUILD =
            Build.TYPE.equals("eng") || Build.TYPE.equals("userdebug");

    private static final String MASK_STRING = "********************************";

    // Throws AssertionError if the input is false.
    public static void assertTrue(boolean cond) {
        if (!cond) {
            throw new AssertionError();
        }
    }

    // Throws AssertionError with the message. We had a method having the form
    //   assertTrue(boolean cond, String message, Object ... args);
    // However a call to that method will cause memory allocation even if the
    // condition is false (due to autoboxing generated by "Object ... args"),
    // so we don't use that anymore.
    public static void fail(String message, Object ... args) {
        throw new AssertionError(
                args.length == 0 ? message : String.format(message, args));
    }

    // Throws NullPointerException if the input is null.
    public static <T> T checkNotNull(T object) {
        if (object == null) throw new NullPointerException();
        return object;
    }

    // Returns true if two input Object are both null or equal
    // to each other.
    public static boolean equals(Object a, Object b) {
        return (a == b) || (a == null ? false : a.equals(b));
    }

    // Returns the next power of two.
    // Returns the input if it is already power of 2.
    // Throws IllegalArgumentException if the input is <= 0 or
    // the answer overflows.
    public static int nextPowerOf2(int n) {
        if (n <= 0 || n > (1 << 30)) throw new IllegalArgumentException("n is invalid: " + n);
        n -= 1;
        n |= n >> 16;
        n |= n >> 8;
        n |= n >> 4;
        n |= n >> 2;
        n |= n >> 1;
        return n + 1;
    }

    // Returns the previous power of two.
    // Returns the input if it is already power of 2.
    // Throws IllegalArgumentException if the input is <= 0
    public static int prevPowerOf2(int n) {
        if (n <= 0) throw new IllegalArgumentException();
        return Integer.highestOneBit(n);
    }

    // Returns the input value x clamped to the range [min, max].
    public static int clamp(int x, int min, int max) {
        if (x > max) return max;
        if (x < min) return min;
        return x;
    }

    // Returns the input value x clamped to the range [min, max].
    public static float clamp(float x, float min, float max) {
        if (x > max) return max;
        if (x < min) return min;
        return x;
    }

    // Returns the input value x clamped to the range [min, max].
    public static long clamp(long x, long min, long max) {
        if (x > max) return max;
        if (x < min) return min;
        return x;
    }

    public static boolean isOpaque(int color) {
        return color >>> 24 == 0xFF;
    }

    public static void swap(int[] array, int i, int j) {
        int temp = array[i];
        array[i] = array[j];
        array[j] = temp;
    }

    
A function thats returns a 64-bit crc for string
Params:
  • in – input string
Returns:a 64-bit crc value
/** * A function thats returns a 64-bit crc for string * * @param in input string * @return a 64-bit crc value */
public static final long crc64Long(String in) { if (in == null || in.length() == 0) { return 0; } return crc64Long(getBytes(in)); } static { // http://bioinf.cs.ucl.ac.uk/downloads/crc64/crc64.c long part; for (int i = 0; i < 256; i++) { part = i; for (int j = 0; j < 8; j++) { long x = ((int) part & 1) != 0 ? POLY64REV : 0; part = (part >> 1) ^ x; } sCrcTable[i] = part; } } public static final long crc64Long(byte[] buffer) { long crc = INITIALCRC; for (int k = 0, n = buffer.length; k < n; ++k) { crc = sCrcTable[(((int) crc) ^ buffer[k]) & 0xff] ^ (crc >> 8); } return crc; } public static byte[] getBytes(String in) { byte[] result = new byte[in.length() * 2]; int output = 0; for (char ch : in.toCharArray()) { result[output++] = (byte) (ch & 0xFF); result[output++] = (byte) (ch >> 8); } return result; } public static void closeSilently(Closeable c) { if (c == null) return; try { c.close(); } catch (IOException t) { Log.w(TAG, "close fail ", t); } } public static int compare(long a, long b) { return a < b ? -1 : a == b ? 0 : 1; } public static int ceilLog2(float value) { int i; for (i = 0; i < 31; i++) { if ((1 << i) >= value) break; } return i; } public static int floorLog2(float value) { int i; for (i = 0; i < 31; i++) { if ((1 << i) > value) break; } return i - 1; } public static void closeSilently(ParcelFileDescriptor fd) { try { if (fd != null) fd.close(); } catch (Throwable t) { Log.w(TAG, "fail to close", t); } } public static void closeSilently(Cursor cursor) { try { if (cursor != null) cursor.close(); } catch (Throwable t) { Log.w(TAG, "fail to close", t); } } public static float interpolateAngle( float source, float target, float progress) { // interpolate the angle from source to target // We make the difference in the range of [-179, 180], this is the // shortest path to change source to target. float diff = target - source; if (diff < 0) diff += 360f; if (diff > 180) diff -= 360f; float result = source + diff * progress; return result < 0 ? result + 360f : result; } public static float interpolateScale( float source, float target, float progress) { return source + progress * (target - source); } public static String ensureNotNull(String value) { return value == null ? "" : value; } public static float parseFloatSafely(String content, float defaultValue) { if (content == null) return defaultValue; try { return Float.parseFloat(content); } catch (NumberFormatException e) { return defaultValue; } } public static int parseIntSafely(String content, int defaultValue) { if (content == null) return defaultValue; try { return Integer.parseInt(content); } catch (NumberFormatException e) { return defaultValue; } } public static boolean isNullOrEmpty(String exifMake) { return TextUtils.isEmpty(exifMake); } public static void waitWithoutInterrupt(Object object) { try { object.wait(); } catch (InterruptedException e) { Log.w(TAG, "unexpected interrupt: " + object); } } public static boolean handleInterrruptedException(Throwable e) { // A helper to deal with the interrupt exception // If an interrupt detected, we will setup the bit again. if (e instanceof InterruptedIOException || e instanceof InterruptedException) { Thread.currentThread().interrupt(); return true; } return false; }
Returns:String with special XML characters escaped.
/** * @return String with special XML characters escaped. */
public static String escapeXml(String s) { StringBuilder sb = new StringBuilder(); for (int i = 0, len = s.length(); i < len; ++i) { char c = s.charAt(i); switch (c) { case '<': sb.append("&lt;"); break; case '>': sb.append("&gt;"); break; case '\"': sb.append("&quot;"); break; case '\'': sb.append("&#039;"); break; case '&': sb.append("&amp;"); break; default: sb.append(c); } } return sb.toString(); } public static String getUserAgent(Context context) { PackageInfo packageInfo; try { packageInfo = context.getPackageManager().getPackageInfo(context.getPackageName(), 0); } catch (NameNotFoundException e) { throw new IllegalStateException("getPackageInfo failed"); } return String.format("%s/%s; %s/%s/%s/%s; %s/%s/%s", packageInfo.packageName, packageInfo.versionName, Build.BRAND, Build.DEVICE, Build.MODEL, Build.ID, Build.VERSION.SDK_INT, Build.VERSION.RELEASE, Build.VERSION.INCREMENTAL); } public static String[] copyOf(String[] source, int newSize) { String[] result = new String[newSize]; newSize = Math.min(source.length, newSize); System.arraycopy(source, 0, result, 0, newSize); return result; } // Mask information for debugging only. It returns <code>info.toString()</code> directly // for debugging build (i.e., 'eng' and 'userdebug') and returns a mask ("****") // in release build to protect the information (e.g. for privacy issue). public static String maskDebugInfo(Object info) { if (info == null) return null; String s = info.toString(); int length = Math.min(s.length(), MASK_STRING.length()); return IS_DEBUG_BUILD ? s : MASK_STRING.substring(0, length); } // This method should be ONLY used for debugging. public static void debug(String message, Object ... args) { Log.v(DEBUG_TAG, String.format(message, args)); } }