com.google.android.exoplayer2.util

Class Util

java.lang.Object

com.google.android.exoplayer2.util.Util

public final class Util
extends java.lang.Object

Miscellaneous utility methods.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	DEVICE Like Build.DEVICE, but in a place where it can be conveniently overridden for local testing.
static java.lang.String	MANUFACTURER Like Build.MANUFACTURER, but in a place where it can be conveniently overridden for local testing.
static java.lang.String	MODEL Like Build.MODEL, but in a place where it can be conveniently overridden for local testing.
static int	SDK_INT Like Build.VERSION.SDK_INT, but in a place where it can be conveniently overridden for local testing.

Method Summary

Modifier and Type	Method and Description
static boolean	areEqual(java.lang.Object o1, java.lang.Object o2) Tests two objects for Object.equals(Object) equality, handling the case where one or both may be null.
static <T> int	binarySearchCeil(java.util.List<? extends java.lang.Comparable<? super T>> list, T value, boolean inclusive, boolean stayInBounds) Returns the index of the smallest value in an list that is greater than (or optionally equal to) a specified value.
static int	binarySearchCeil(long[] a, long value, boolean inclusive, boolean stayInBounds) Returns the index of the smallest value in an array that is greater than (or optionally equal to) a specified value.
static int	binarySearchFloor(int[] a, int value, boolean inclusive, boolean stayInBounds) Returns the index of the largest value in an array that is less than (or optionally equal to) a specified value.
static <T> int	binarySearchFloor(java.util.List<? extends java.lang.Comparable<? super T>> list, T value, boolean inclusive, boolean stayInBounds) Returns the index of the largest value in an list that is less than (or optionally equal to) a specified value.
static int	binarySearchFloor(long[] a, long value, boolean inclusive, boolean stayInBounds) Returns the index of the largest value in an array that is less than (or optionally equal to) a specified value.
static int	ceilDivide(int numerator, int denominator) Divides a numerator by a denominator, returning the ceiled result.
static long	ceilDivide(long numerator, long denominator) Divides a numerator by a denominator, returning the ceiled result.
static void	closeQuietly(DataSource dataSource) Closes a DataSource, suppressing any IOException that may occur.
static void	closeQuietly(java.io.OutputStream outputStream) Closes an OutputStream, suppressing any IOException that may occur.
static int	constrainValue(int value, int min, int max) Constrains a value to the specified bounds.
static boolean	contains(java.lang.Object[] items, java.lang.Object item) Tests whether an items array contains an object equal to item, according to Object.equals(Object).
static int	crc(byte[] bytes, int start, int end, int initialValue) Returns the result of updating a CRC with the specified bytes in a "most significant bit first" order.
static java.lang.String	escapeFileName(java.lang.String fileName) Escapes a string so that it's safe for use as a file or directory name on at least FAT32 filesystems.
static byte[]	getBytesFromHexString(java.lang.String hexString) Returns a byte array containing values parsed from the hex string provided.
static java.lang.String	getCommaDelimitedSimpleClassNames(java.lang.Object[] objects) Returns a string with comma delimited simple names of each object's class.
static int	getDefaultBufferSize(int trackType) Maps a C TRACK_TYPE_* constant to the corresponding C DEFAULT_*_BUFFER_SIZE constant.
static java.lang.String	getHexString(byte[] bytes) Returns a hex string representation of the given byte array.
static int	getIntegerCodeForString(java.lang.String string) Returns the integer equal to the big-endian concatenation of the characters in string as bytes.
static int	getPcmEncoding(int bitDepth) Converts a sample bit depth to a corresponding PCM encoding constant.
static android.graphics.Point	getPhysicalDisplaySize(android.content.Context context) Gets the physical size of the default display, in pixels.
static android.graphics.Point	getPhysicalDisplaySize(android.content.Context context, android.view.Display display) Gets the physical size of the specified display, in pixels.
static DataSpec	getRemainderDataSpec(DataSpec dataSpec, int bytesLoaded) Given a DataSpec and a number of bytes already loaded, returns a DataSpec that represents the remainder of the data.
static java.lang.String	getUserAgent(android.content.Context context, java.lang.String applicationName) Returns a user agent string based on the given application name and the library version.
static byte[]	getUtf8Bytes(java.lang.String value) Returns a new byte array containing the code points of a String encoded using UTF-8.
static int	inferContentType(java.lang.String fileName) Makes a best guess to infer the type from a file name.
static boolean	isLocalFileUri(android.net.Uri uri) Returns true if the URI is a path to a local file or a reference to a local file.
static boolean	maybeRequestReadExternalStoragePermission(android.app.Activity activity, android.net.Uri... uris) Checks whether it's necessary to request the Manifest.permission.READ_EXTERNAL_STORAGE permission read the specified Uris, requesting the permission if necessary.
static java.util.concurrent.ExecutorService	newSingleThreadExecutor(java.lang.String threadName) Instantiates a new single threaded executor whose thread has the specified name.
static java.lang.String	normalizeLanguageCode(java.lang.String language) Returns a normalized RFC 5646 language code.
static long	parseXsDateTime(java.lang.String value) Parses an xs:dateTime attribute value, returning the parsed timestamp in milliseconds since the epoch.
static long	parseXsDuration(java.lang.String value) Parses an xs:duration attribute value, returning the parsed duration in milliseconds.
static long	scaleLargeTimestamp(long timestamp, long multiplier, long divisor) Scales a large timestamp.
static long[]	scaleLargeTimestamps(java.util.List<java.lang.Long> timestamps, long multiplier, long divisor) Applies scaleLargeTimestamp(long, long, long) to a list of unscaled timestamps.
static void	scaleLargeTimestampsInPlace(long[] timestamps, long multiplier, long divisor) Applies scaleLargeTimestamp(long, long, long) to an array of unscaled timestamps.
static java.lang.String	sha1(java.lang.String input) Returns the SHA-1 digest of input as a hex string.
static int[]	toArray(java.util.List<java.lang.Integer> list) Converts a list of integers to a primitive array.
static byte[]	toByteArray(java.io.InputStream inputStream) Converts the entirety of an InputStream to a byte array.
static java.lang.String	toLowerInvariant(java.lang.String text) Converts text to lower case using Locale.US.
static java.lang.String	unescapeFileName(java.lang.String fileName) Unescapes an escaped file or directory name back to its original value.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SDK_INT

public static final int SDK_INT

Like Build.VERSION.SDK_INT, but in a place where it can be conveniently overridden for local testing.

DEVICE

public static final java.lang.String DEVICE

Like Build.DEVICE, but in a place where it can be conveniently overridden for local testing.

MANUFACTURER

public static final java.lang.String MANUFACTURER

Like Build.MANUFACTURER, but in a place where it can be conveniently overridden for local testing.

MODEL

public static final java.lang.String MODEL

Like Build.MODEL, but in a place where it can be conveniently overridden for local testing.

Method Detail

toByteArray

public static byte[] toByteArray(java.io.InputStream inputStream)
                          throws java.io.IOException

Converts the entirety of an InputStream to a byte array.

Parameters:

inputStream - the InputStream to be read. The input stream is not closed by this method.

Returns:

a byte array containing all of the inputStream's bytes.

Throws:

java.io.IOException - if an error occurs reading from the stream.

maybeRequestReadExternalStoragePermission

public static boolean maybeRequestReadExternalStoragePermission(android.app.Activity activity,
                                                                android.net.Uri... uris)

Checks whether it's necessary to request the Manifest.permission.READ_EXTERNAL_STORAGE permission read the specified Uris, requesting the permission if necessary.

Parameters:

activity - The host activity for checking and requesting the permission.

uris - Uris that may require Manifest.permission.READ_EXTERNAL_STORAGE to read.

Returns:

Whether a permission request was made.

isLocalFileUri

public static boolean isLocalFileUri(android.net.Uri uri)

Returns true if the URI is a path to a local file or a reference to a local file.

Parameters:

uri - The uri to test.

areEqual

public static boolean areEqual(java.lang.Object o1,
                               java.lang.Object o2)

Tests two objects for Object.equals(Object) equality, handling the case where one or both may be null.

Parameters:

o1 - The first object.

o2 - The second object.

Returns:

o1 == null ? o2 == null : o1.equals(o2).

contains

public static boolean contains(java.lang.Object[] items,
                               java.lang.Object item)

Tests whether an items array contains an object equal to item, according to Object.equals(Object).

If item is null then true is returned if and only if items contains null.

Parameters:

items - The array of items to search.

item - The item to search for.

Returns:

True if the array contains an object equal to the item being searched for.

newSingleThreadExecutor

public static java.util.concurrent.ExecutorService newSingleThreadExecutor(java.lang.String threadName)

Instantiates a new single threaded executor whose thread has the specified name.

Parameters:

threadName - The name of the thread.

Returns:

The executor.

closeQuietly

public static void closeQuietly(DataSource dataSource)

Closes a DataSource, suppressing any IOException that may occur.

Parameters:

dataSource - The DataSource to close.

closeQuietly

public static void closeQuietly(java.io.OutputStream outputStream)

Closes an OutputStream, suppressing any IOException that may occur.

Parameters:

outputStream - The OutputStream to close.

normalizeLanguageCode

public static java.lang.String normalizeLanguageCode(java.lang.String language)

Returns a normalized RFC 5646 language code.

Parameters:

language - A possibly non-normalized RFC 5646 language code.

Returns:

The normalized code, or null if the input was null.

getUtf8Bytes

public static byte[] getUtf8Bytes(java.lang.String value)

Returns a new byte array containing the code points of a String encoded using UTF-8.

Parameters:

value - The String whose bytes should be obtained.

Returns:

The code points encoding using UTF-8.

toLowerInvariant

public static java.lang.String toLowerInvariant(java.lang.String text)

Converts text to lower case using Locale.US.

Parameters:

text - The text to convert.

Returns:

The lower case text, or null if text is null.

ceilDivide

public static int ceilDivide(int numerator,
                             int denominator)

Divides a numerator by a denominator, returning the ceiled result.

Parameters:

numerator - The numerator to divide.

denominator - The denominator to divide by.

Returns:

The ceiled result of the division.

ceilDivide

public static long ceilDivide(long numerator,
                              long denominator)

Divides a numerator by a denominator, returning the ceiled result.

Parameters:

numerator - The numerator to divide.

denominator - The denominator to divide by.

Returns:

The ceiled result of the division.

constrainValue

public static int constrainValue(int value,
                                 int min,
                                 int max)

Constrains a value to the specified bounds.

Parameters:

value - The value to constrain.

min - The lower bound.

max - The upper bound.

Returns:

The constrained value Math.max(min, Math.min(value, max)).

binarySearchFloor

public static int binarySearchFloor(int[] a,
                                    int value,
                                    boolean inclusive,
                                    boolean stayInBounds)

Returns the index of the largest value in an array that is less than (or optionally equal to) a specified value.

The search is performed using a binary search algorithm, so the array must be sorted.

Parameters:

a - The array to search.

value - The value being searched for.

inclusive - If the value is present in the array, whether to return the corresponding index. If false then the returned index corresponds to the largest value in the array that is strictly less than the value.

stayInBounds - If true, then 0 will be returned in the case that the value is smaller than the smallest value in the array. If false then -1 will be returned.

binarySearchFloor

public static int binarySearchFloor(long[] a,
                                    long value,
                                    boolean inclusive,
                                    boolean stayInBounds)

Returns the index of the largest value in an array that is less than (or optionally equal to) a specified value.

The search is performed using a binary search algorithm, so the array must be sorted.

Parameters:

a - The array to search.

value - The value being searched for.

inclusive - If the value is present in the array, whether to return the corresponding index. If false then the returned index corresponds to the largest value in the array that is strictly less than the value.

stayInBounds - If true, then 0 will be returned in the case that the value is smaller than the smallest value in the array. If false then -1 will be returned.

binarySearchCeil

public static int binarySearchCeil(long[] a,
                                   long value,
                                   boolean inclusive,
                                   boolean stayInBounds)

Returns the index of the smallest value in an array that is greater than (or optionally equal to) a specified value.

The search is performed using a binary search algorithm, so the array must be sorted.

Parameters:

a - The array to search.

value - The value being searched for.

inclusive - If the value is present in the array, whether to return the corresponding index. If false then the returned index corresponds to the largest value in the array that is strictly less than the value.

stayInBounds - If true, then (a.length - 1) will be returned in the case that the value is greater than the largest value in the array. If false then a.length will be returned.

binarySearchFloor

public static <T> int binarySearchFloor(java.util.List<? extends java.lang.Comparable<? super T>> list,
                                        T value,
                                        boolean inclusive,
                                        boolean stayInBounds)

Returns the index of the largest value in an list that is less than (or optionally equal to) a specified value.

The search is performed using a binary search algorithm, so the list must be sorted.

Type Parameters:

T - The type of values being searched.

Parameters:

list - The list to search.

value - The value being searched for.

inclusive - If the value is present in the list, whether to return the corresponding index. If false then the returned index corresponds to the largest value in the list that is strictly less than the value.

stayInBounds - If true, then 0 will be returned in the case that the value is smaller than the smallest value in the list. If false then -1 will be returned.

binarySearchCeil

public static <T> int binarySearchCeil(java.util.List<? extends java.lang.Comparable<? super T>> list,
                                       T value,
                                       boolean inclusive,
                                       boolean stayInBounds)

Returns the index of the smallest value in an list that is greater than (or optionally equal to) a specified value.

The search is performed using a binary search algorithm, so the list must be sorted.

Type Parameters:

T - The type of values being searched.

Parameters:

list - The list to search.

value - The value being searched for.

inclusive - If the value is present in the list, whether to return the corresponding index. If false then the returned index corresponds to the smallest value in the list that is strictly greater than the value.

stayInBounds - If true, then (list.size() - 1) will be returned in the case that the value is greater than the largest value in the list. If false then list.size() will be returned.

parseXsDuration

public static long parseXsDuration(java.lang.String value)

Parses an xs:duration attribute value, returning the parsed duration in milliseconds.

Parameters:

value - The attribute value to decode.

Returns:

The parsed duration in milliseconds.

parseXsDateTime

public static long parseXsDateTime(java.lang.String value)
                            throws java.text.ParseException

Parses an xs:dateTime attribute value, returning the parsed timestamp in milliseconds since the epoch.

Parameters:

value - The attribute value to decode.

Returns:

The parsed timestamp in milliseconds since the epoch.

Throws:

java.text.ParseException

scaleLargeTimestamp

public static long scaleLargeTimestamp(long timestamp,
                                       long multiplier,
                                       long divisor)

Scales a large timestamp.

Logically, scaling consists of a multiplication followed by a division. The actual operations performed are designed to minimize the probability of overflow.

Parameters:

timestamp - The timestamp to scale.

multiplier - The multiplier.

divisor - The divisor.

Returns:

The scaled timestamp.

scaleLargeTimestamps

public static long[] scaleLargeTimestamps(java.util.List<java.lang.Long> timestamps,
                                          long multiplier,
                                          long divisor)

Applies scaleLargeTimestamp(long, long, long) to a list of unscaled timestamps.

Parameters:

timestamps - The timestamps to scale.

multiplier - The multiplier.

divisor - The divisor.

Returns:

The scaled timestamps.

scaleLargeTimestampsInPlace

public static void scaleLargeTimestampsInPlace(long[] timestamps,
                                               long multiplier,
                                               long divisor)

Applies scaleLargeTimestamp(long, long, long) to an array of unscaled timestamps.

Parameters:

timestamps - The timestamps to scale.

multiplier - The multiplier.

divisor - The divisor.

toArray

public static int[] toArray(java.util.List<java.lang.Integer> list)

Converts a list of integers to a primitive array.

Parameters:

list - A list of integers.

Returns:

The list in array form, or null if the input list was null.

getRemainderDataSpec

public static DataSpec getRemainderDataSpec(DataSpec dataSpec,
                                            int bytesLoaded)

Given a DataSpec and a number of bytes already loaded, returns a DataSpec that represents the remainder of the data.

Parameters:

dataSpec - The original DataSpec.

bytesLoaded - The number of bytes already loaded.

Returns:

A DataSpec that represents the remainder of the data.

getIntegerCodeForString

public static int getIntegerCodeForString(java.lang.String string)

Returns the integer equal to the big-endian concatenation of the characters in string as bytes. The string must be no more than four characters long.

Parameters:

string - A string no more than four characters long.

getBytesFromHexString

public static byte[] getBytesFromHexString(java.lang.String hexString)

Returns a byte array containing values parsed from the hex string provided.

Parameters:

hexString - The hex string to convert to bytes.

Returns:

A byte array containing values parsed from the hex string provided.

getHexString

public static java.lang.String getHexString(byte[] bytes)

Returns a hex string representation of the given byte array.

Parameters:

bytes - The byte array.

getCommaDelimitedSimpleClassNames

public static java.lang.String getCommaDelimitedSimpleClassNames(java.lang.Object[] objects)

Returns a string with comma delimited simple names of each object's class.

Parameters:

objects - The objects whose simple class names should be comma delimited and returned.

Returns:

A string with comma delimited simple names of each object's class.

getUserAgent

public static java.lang.String getUserAgent(android.content.Context context,
                                            java.lang.String applicationName)

Returns a user agent string based on the given application name and the library version.

Parameters:

context - A valid context of the calling application.

applicationName - String that will be prefix'ed to the generated user agent.

Returns:

A user agent string generated using the applicationName and the library version.

getPcmEncoding

public static int getPcmEncoding(int bitDepth)

Converts a sample bit depth to a corresponding PCM encoding constant.

Parameters:

bitDepth - The bit depth. Supported values are 8, 16, 24 and 32.

Returns:

The corresponding encoding. One of C.ENCODING_PCM_8BIT, C.ENCODING_PCM_16BIT, C.ENCODING_PCM_24BIT and C.ENCODING_PCM_32BIT. If the bit depth is unsupported then C.ENCODING_INVALID is returned.

inferContentType

public static int inferContentType(java.lang.String fileName)

Makes a best guess to infer the type from a file name.

Parameters:

fileName - Name of the file. It can include the path of the file.

Returns:

The content type.

getDefaultBufferSize

public static int getDefaultBufferSize(int trackType)

Maps a C TRACK_TYPE_* constant to the corresponding C DEFAULT_*_BUFFER_SIZE constant.

Parameters:

trackType - The track type.

Returns:

The corresponding default buffer size in bytes.

escapeFileName

public static java.lang.String escapeFileName(java.lang.String fileName)

Escapes a string so that it's safe for use as a file or directory name on at least FAT32 filesystems. FAT32 is the most restrictive of all filesystems still commonly used today.

For simplicity, this only handles common characters known to be illegal on FAT32: <, >, :, ", /, \, |, ?, and *. % is also escaped since it is used as the escape character. Escaping is performed in a consistent way so that no collisions occur and unescapeFileName(String) can be used to retrieve the original file name.

Parameters:

fileName - File name to be escaped.

Returns:

An escaped file name which will be safe for use on at least FAT32 filesystems.

unescapeFileName

public static java.lang.String unescapeFileName(java.lang.String fileName)

Unescapes an escaped file or directory name back to its original value.

See escapeFileName(String) for more information.

Parameters:

fileName - File name to be unescaped.

Returns:

The original value of the file name before it was escaped, or null if the escaped fileName seems invalid.

crc

public static int crc(byte[] bytes,
                      int start,
                      int end,
                      int initialValue)

Returns the result of updating a CRC with the specified bytes in a "most significant bit first" order.

Parameters:

bytes - Array containing the bytes to update the crc value with.

start - The index to the first byte in the byte range to update the crc with.

end - The index after the last byte in the byte range to update the crc with.

initialValue - The initial value for the crc calculation.

Returns:

The result of updating the initial value with the specified bytes.

sha1

public static java.lang.String sha1(java.lang.String input)

Returns the SHA-1 digest of input as a hex string.

Parameters:

input - The string whose SHA-1 digest is required.

getPhysicalDisplaySize

public static android.graphics.Point getPhysicalDisplaySize(android.content.Context context)

Gets the physical size of the default display, in pixels.

Parameters:

context - Any context.

Returns:

The physical display size, in pixels.

getPhysicalDisplaySize

public static android.graphics.Point getPhysicalDisplaySize(android.content.Context context,
                                                            android.view.Display display)

Gets the physical size of the specified display, in pixels.

Parameters:

context - Any context.

display - The display whose size is to be returned.

Returns:

The physical display size, in pixels.