# CacheDataSource

Artifact: [androidx.media3:media3-datasource](https://developer.android.com/jetpack/androidx/releases/media3) [View Source](https://cs.android.com/search?q=file:androidx/media3/datasource/cache/CacheDataSource.java+class:androidx.media3.datasource.cache.CacheDataSource)

*** ** * ** ***


```
@UnstableApi
public final class CacheDataSource implements DataSource
```

<br />

*** ** * ** ***

A `https://developer.android.com/reference/androidx/media3/datasource/DataSource` that reads and writes a `https://developer.android.com/reference/androidx/media3/datasource/cache/Cache`. Requests are fulfilled from the cache when possible. When data is not cached it is requested from an upstream `https://developer.android.com/reference/androidx/media3/datasource/DataSource` and written into the cache.

## Summary

| ### Nested types |
|---|
| `@https://developer.android.com/reference/java/lang/annotation/Documented.html @https://developer.android.com/reference/java/lang/annotation/Retention.html(value = https://developer.android.com/reference/java/lang/annotation/RetentionPolicy.html#SOURCE) @https://developer.android.com/reference/java/lang/annotation/Target.html(value = ) @https://developer.android.com/reference/androidx/annotation/IntDef(value = ) public annotation https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.CacheIgnoredReason` Reasons the cache may be ignored. |
| `public interface https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.EventListener` Listener of `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource` events. |
| `public final class https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.Factory implements https://developer.android.com/reference/androidx/media3/datasource/DataSource.Factory` `https://developer.android.com/reference/androidx/media3/datasource/DataSource.Factory` for `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource` instances. |
| `@https://developer.android.com/reference/java/lang/annotation/Documented.html @https://developer.android.com/reference/java/lang/annotation/Retention.html(value = https://developer.android.com/reference/java/lang/annotation/RetentionPolicy.html#SOURCE) @https://developer.android.com/reference/java/lang/annotation/Target.html(value = https://developer.android.com/reference/java/lang/annotation/ElementType.html#TYPE_USE) @https://developer.android.com/reference/androidx/annotation/IntDef(flag = true, value = ) public annotation https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.Flags` Flags controlling the CacheDataSource's behavior. |

| ### Constants |
|---|---|
| `static final int` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#CACHE_IGNORED_REASON_ERROR() = 0` Cache ignored due to a cache related error. |
| `static final int` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#CACHE_IGNORED_REASON_UNSET_LENGTH() = 1` Cache ignored due to a request with an unset length. |
| `static final int` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#FLAG_BLOCK_ON_CACHE() = 1` A flag indicating whether we will block reads if the cache key is locked. |
| `static final int` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#FLAG_IGNORE_CACHE_FOR_UNSET_LENGTH_REQUESTS() = 4` A flag indicating that the cache should be bypassed for requests whose lengths are unset. |
| `static final int` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#FLAG_IGNORE_CACHE_ON_ERROR() = 2` A flag indicating whether the cache is bypassed following any cache related error. |

| ### Public fields |
|---|---|
| `final https://developer.android.com/reference/androidx/media3/datasource/cache/Cache` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#cache()` |
| `final https://developer.android.com/reference/androidx/media3/datasource/cache/CacheKeyFactory` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#cacheKeyFactory()` |

| ### Public constructors |
|---|
| `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#CacheDataSource(androidx.media3.datasource.cache.Cache,androidx.media3.datasource.DataSource)(https://developer.android.com/reference/androidx/media3/datasource/cache/Cache cache, @https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/DataSource upstreamDataSource)` Constructs an instance with default `https://developer.android.com/reference/androidx/media3/datasource/DataSource` and `https://developer.android.com/reference/androidx/media3/datasource/DataSink` instances for reading and writing the cache. |
| `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#CacheDataSource(androidx.media3.datasource.cache.Cache,androidx.media3.datasource.DataSource,int)( https://developer.android.com/reference/androidx/media3/datasource/cache/Cache cache, @https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/DataSource upstreamDataSource, @https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.Flags int flags )` Constructs an instance with default `https://developer.android.com/reference/androidx/media3/datasource/DataSource` and `https://developer.android.com/reference/androidx/media3/datasource/DataSink` instances for reading and writing the cache. |
| `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#CacheDataSource(androidx.media3.datasource.cache.Cache,androidx.media3.datasource.DataSource,androidx.media3.datasource.DataSource,androidx.media3.datasource.DataSink,int,androidx.media3.datasource.cache.CacheDataSource.EventListener)( https://developer.android.com/reference/androidx/media3/datasource/cache/Cache cache, @https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/DataSource upstreamDataSource, https://developer.android.com/reference/androidx/media3/datasource/DataSource cacheReadDataSource, @https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/DataSink cacheWriteDataSink, @https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.Flags int flags, @https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.EventListener eventListener )` Constructs an instance with arbitrary `https://developer.android.com/reference/androidx/media3/datasource/DataSource` and `https://developer.android.com/reference/androidx/media3/datasource/DataSink` instances for reading and writing the cache. |
| `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#CacheDataSource(androidx.media3.datasource.cache.Cache,androidx.media3.datasource.DataSource,androidx.media3.datasource.DataSource,androidx.media3.datasource.DataSink,int,androidx.media3.datasource.cache.CacheDataSource.EventListener,androidx.media3.datasource.cache.CacheKeyFactory)( https://developer.android.com/reference/androidx/media3/datasource/cache/Cache cache, @https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/DataSource upstreamDataSource, https://developer.android.com/reference/androidx/media3/datasource/DataSource cacheReadDataSource, @https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/DataSink cacheWriteDataSink, @https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.Flags int flags, @https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.EventListener eventListener, @https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/cache/CacheKeyFactory cacheKeyFactory )` Constructs an instance with arbitrary `https://developer.android.com/reference/androidx/media3/datasource/DataSource` and `https://developer.android.com/reference/androidx/media3/datasource/DataSink` instances for reading and writing the cache. |

| ### Public methods |
|---|---|
| `void` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#addTransferListener(androidx.media3.datasource.TransferListener)(https://developer.android.com/reference/androidx/media3/datasource/TransferListener transferListener)` Adds a `https://developer.android.com/reference/androidx/media3/datasource/TransferListener` to listen to data transfers. |
| `void` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#close()()` Closes the source. |
| `https://developer.android.com/reference/androidx/media3/datasource/cache/Cache` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#getCache()()` Returns the `https://developer.android.com/reference/androidx/media3/datasource/cache/Cache` used by this instance. |
| `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheKeyFactory` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#getCacheKeyFactory()()` Returns the `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheKeyFactory` used by this instance. |
| `https://developer.android.com/reference/java/util/Map.html<https://developer.android.com/reference/java/lang/String.html, https://developer.android.com/reference/java/util/List.html<https://developer.android.com/reference/java/lang/String.html>>` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#getResponseHeaders()()` When the source is open, returns the response headers associated with the last `https://developer.android.com/reference/androidx/media3/datasource/DataSource#open(androidx.media3.datasource.DataSpec)` call. |
| `@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/android/net/Uri.html` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#getUri()()` When the source is open, returns the `https://developer.android.com/reference/android/net/Uri.html` from which data is being read. |
| `long` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#open(androidx.media3.datasource.DataSpec)(https://developer.android.com/reference/androidx/media3/datasource/DataSpec dataSpec)` Opens the source to read the specified data. |
| `int` | `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#read(byte[],int,int)(byte[] buffer, int offset, int length)` Reads up to `length` bytes of data from the input. |

## Constants

### CACHE_IGNORED_REASON_ERROR

```
public static final int CACHE_IGNORED_REASON_ERROR = 0
```

Cache ignored due to a cache related error.

### CACHE_IGNORED_REASON_UNSET_LENGTH

```
public static final int CACHE_IGNORED_REASON_UNSET_LENGTH = 1
```

Cache ignored due to a request with an unset length.

### FLAG_BLOCK_ON_CACHE

```
public static final int FLAG_BLOCK_ON_CACHE = 1
```

A flag indicating whether we will block reads if the cache key is locked. If unset then data is read from upstream if the cache key is locked, regardless of whether the data is cached.

### FLAG_IGNORE_CACHE_FOR_UNSET_LENGTH_REQUESTS

```
public static final int FLAG_IGNORE_CACHE_FOR_UNSET_LENGTH_REQUESTS = 4
```

A flag indicating that the cache should be bypassed for requests whose lengths are unset. This flag is provided for legacy reasons only.

### FLAG_IGNORE_CACHE_ON_ERROR

```
public static final int FLAG_IGNORE_CACHE_ON_ERROR = 2
```

A flag indicating whether the cache is bypassed following any cache related error. If set then cache related exceptions may be thrown for one cycle of open, read and close calls. Subsequent cycles of these calls will then bypass the cache.

## Public fields

### cache

```
public final Cache cache
```

### cacheKeyFactory

```
public final CacheKeyFactory cacheKeyFactory
```

## Public constructors

### CacheDataSource

```
public CacheDataSource(Cache cache, @Nullable DataSource upstreamDataSource)
```

Constructs an instance with default `https://developer.android.com/reference/androidx/media3/datasource/DataSource` and `https://developer.android.com/reference/androidx/media3/datasource/DataSink` instances for reading and writing the cache.

| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/media3/datasource/cache/Cache cache` | The cache. |
| `@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/DataSource upstreamDataSource` | A `https://developer.android.com/reference/androidx/media3/datasource/DataSource` for reading data not in the cache. If null, reading will fail if a cache miss occurs. |

### CacheDataSource

```
public CacheDataSource(
    Cache cache,
    @Nullable DataSource upstreamDataSource,
    @CacheDataSource.Flags int flags
)
```

Constructs an instance with default `https://developer.android.com/reference/androidx/media3/datasource/DataSource` and `https://developer.android.com/reference/androidx/media3/datasource/DataSink` instances for reading and writing the cache.

| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/media3/datasource/cache/Cache cache` | The cache. |
| `@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/DataSource upstreamDataSource` | A `https://developer.android.com/reference/androidx/media3/datasource/DataSource` for reading data not in the cache. If null, reading will fail if a cache miss occurs. |
| `@https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.Flags int flags` | A combination of `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#FLAG_BLOCK_ON_CACHE()`, `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#FLAG_IGNORE_CACHE_ON_ERROR()` and `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#FLAG_IGNORE_CACHE_FOR_UNSET_LENGTH_REQUESTS()`, or 0. |

### CacheDataSource

```
public CacheDataSource(
    Cache cache,
    @Nullable DataSource upstreamDataSource,
    DataSource cacheReadDataSource,
    @Nullable DataSink cacheWriteDataSink,
    @CacheDataSource.Flags int flags,
    @Nullable CacheDataSource.EventListener eventListener
)
```

Constructs an instance with arbitrary `https://developer.android.com/reference/androidx/media3/datasource/DataSource` and `https://developer.android.com/reference/androidx/media3/datasource/DataSink` instances for reading and writing the cache. One use of this constructor is to allow data to be transformed before it is written to disk.

| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/media3/datasource/cache/Cache cache` | The cache. |
| `@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/DataSource upstreamDataSource` | A `https://developer.android.com/reference/androidx/media3/datasource/DataSource` for reading data not in the cache. If null, reading will fail if a cache miss occurs. |
| `https://developer.android.com/reference/androidx/media3/datasource/DataSource cacheReadDataSource` | A `https://developer.android.com/reference/androidx/media3/datasource/DataSource` for reading data from the cache. |
| `@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/DataSink cacheWriteDataSink` | A `https://developer.android.com/reference/androidx/media3/datasource/DataSink` for writing data to the cache. If null, cache is accessed read-only. |
| `@https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.Flags int flags` | A combination of `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#FLAG_BLOCK_ON_CACHE()`, `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#FLAG_IGNORE_CACHE_ON_ERROR()` and `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#FLAG_IGNORE_CACHE_FOR_UNSET_LENGTH_REQUESTS()`, or 0. |
| `@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.EventListener eventListener` | An optional `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.EventListener` to receive events. |

### CacheDataSource

```
public CacheDataSource(
    Cache cache,
    @Nullable DataSource upstreamDataSource,
    DataSource cacheReadDataSource,
    @Nullable DataSink cacheWriteDataSink,
    @CacheDataSource.Flags int flags,
    @Nullable CacheDataSource.EventListener eventListener,
    @Nullable CacheKeyFactory cacheKeyFactory
)
```

Constructs an instance with arbitrary `https://developer.android.com/reference/androidx/media3/datasource/DataSource` and `https://developer.android.com/reference/androidx/media3/datasource/DataSink` instances for reading and writing the cache. One use of this constructor is to allow data to be transformed before it is written to disk.

| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/media3/datasource/cache/Cache cache` | The cache. |
| `@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/DataSource upstreamDataSource` | A `https://developer.android.com/reference/androidx/media3/datasource/DataSource` for reading data not in the cache. If null, reading will fail if a cache miss occurs. |
| `https://developer.android.com/reference/androidx/media3/datasource/DataSource cacheReadDataSource` | A `https://developer.android.com/reference/androidx/media3/datasource/DataSource` for reading data from the cache. |
| `@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/DataSink cacheWriteDataSink` | A `https://developer.android.com/reference/androidx/media3/datasource/DataSink` for writing data to the cache. If null, cache is accessed read-only. |
| `@https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.Flags int flags` | A combination of `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#FLAG_BLOCK_ON_CACHE()`, `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#FLAG_IGNORE_CACHE_ON_ERROR()` and `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource#FLAG_IGNORE_CACHE_FOR_UNSET_LENGTH_REQUESTS()`, or 0. |
| `@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.EventListener eventListener` | An optional `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheDataSource.EventListener` to receive events. |
| `@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/androidx/media3/datasource/cache/CacheKeyFactory cacheKeyFactory` | An optional factory for cache keys. |

## Public methods

### addTransferListener

```
public void addTransferListener(TransferListener transferListener)
```

Adds a `https://developer.android.com/reference/androidx/media3/datasource/TransferListener` to listen to data transfers. This method is not thread-safe.

| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/media3/datasource/TransferListener transferListener` | A `https://developer.android.com/reference/androidx/media3/datasource/TransferListener`. |

### close

```
public void close()
```

Closes the source. This method must be called even if the corresponding call to `https://developer.android.com/reference/androidx/media3/datasource/DataSource#open(androidx.media3.datasource.DataSpec)` threw an `https://developer.android.com/reference/java/io/IOException.html`.

| Throws |
|---|---|
| `https://developer.android.com/reference/java/io/IOException.html` | If an error occurs closing the source. |

### getCache

```
public Cache getCache()
```

Returns the `https://developer.android.com/reference/androidx/media3/datasource/cache/Cache` used by this instance.

### getCacheKeyFactory

```
public CacheKeyFactory getCacheKeyFactory()
```

Returns the `https://developer.android.com/reference/androidx/media3/datasource/cache/CacheKeyFactory` used by this instance.

### getResponseHeaders

```
public Map<String, List<String>> getResponseHeaders()
```

When the source is open, returns the response headers associated with the last `https://developer.android.com/reference/androidx/media3/datasource/DataSource#open(androidx.media3.datasource.DataSpec)` call. Otherwise, returns an empty map.

Key look-up in the returned map is case-insensitive.

### getUri

```
public @Nullable Uri getUri()
```

When the source is open, returns the `https://developer.android.com/reference/android/net/Uri.html` from which data is being read. The returned `https://developer.android.com/reference/android/net/Uri.html` will be identical to the one passed `https://developer.android.com/reference/androidx/media3/datasource/DataSource#open(androidx.media3.datasource.DataSpec)` in the `https://developer.android.com/reference/androidx/media3/datasource/DataSpec` unless redirection has occurred. If redirection has occurred, the `https://developer.android.com/reference/android/net/Uri.html` after redirection is returned.

| Returns |
|---|---|
| `@https://developer.android.com/reference/androidx/annotation/Nullable https://developer.android.com/reference/android/net/Uri.html` | The `https://developer.android.com/reference/android/net/Uri.html` from which data is being read, or null if the source is not open. |

### open

```
public long open(DataSpec dataSpec)
```

Opens the source to read the specified data. If an `https://developer.android.com/reference/java/io/IOException.html` is thrown, callers must still call `https://developer.android.com/reference/androidx/media3/datasource/DataSource#close()` to ensure that any partial effects of the invocation are cleaned up.

The following edge case behaviors apply:

- If the `https://developer.android.com/reference/androidx/media3/datasource/DataSpec#position()` is within the resource, but the `https://developer.android.com/reference/androidx/media3/datasource/DataSpec#length()` extends beyond the end of the resource, then `https://developer.android.com/reference/androidx/media3/datasource/DataSource#open(androidx.media3.datasource.DataSpec)` will succeed and data from the requested position to the end of the resource will be made available through `https://developer.android.com/reference/androidx/media3/common/DataReader#read(byte[],int,int)`.
- If the `https://developer.android.com/reference/androidx/media3/datasource/DataSpec#position()` is equal to the length of the resource, then `https://developer.android.com/reference/androidx/media3/datasource/DataSource#open(androidx.media3.datasource.DataSpec)` will succeed, and `https://developer.android.com/reference/androidx/media3/common/DataReader#read(byte[],int,int)` will immediately return `https://developer.android.com/reference/androidx/media3/common/C#RESULT_END_OF_INPUT()`.
- If the `https://developer.android.com/reference/androidx/media3/datasource/DataSpec#position()` is greater than the length of the resource, then `https://developer.android.com/reference/androidx/media3/datasource/DataSource#open(androidx.media3.datasource.DataSpec)` will throw an `https://developer.android.com/reference/java/io/IOException.html` for which `https://developer.android.com/reference/androidx/media3/datasource/DataSourceException#isCausedByPositionOutOfRange(java.io.IOException)` will be `true`.

| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/media3/datasource/DataSpec dataSpec` | Defines the data to be read. |

| Returns |
|---|---|
| `long` | The number of bytes that can be read from the opened source. For unbounded requests (i.e., requests where `https://developer.android.com/reference/androidx/media3/datasource/DataSpec#length()` equals `https://developer.android.com/reference/androidx/media3/common/C#LENGTH_UNSET()`) this value is the resolved length of the request, or `https://developer.android.com/reference/androidx/media3/common/C#LENGTH_UNSET()` if the length is still unresolved. For all other requests, the value returned will be equal to the request's `https://developer.android.com/reference/androidx/media3/datasource/DataSpec#length()`. |

| Throws |
|---|---|
| `https://developer.android.com/reference/java/io/IOException.html` | If an error occurs opening the source. `https://developer.android.com/reference/androidx/media3/datasource/DataSourceException` can be thrown or used as a cause of the thrown exception to specify the reason of the error. |

### read

```
public int read(byte[] buffer, int offset, int length)
```

Reads up to `length` bytes of data from the input.

If `readLength` is zero then 0 is returned. Otherwise, if no data is available because the end of the opened range has been reached, then `https://developer.android.com/reference/androidx/media3/common/C#RESULT_END_OF_INPUT()` is returned. Otherwise, the call will block until at least one byte of data has been read and the number of bytes read is returned.

| Parameters |
|---|---|
| `byte[] buffer` | A target array into which data should be written. |
| `int offset` | The offset into the target array at which to write. |
| `int length` | The maximum number of bytes to read from the input. |

| Returns |
|---|---|
| `int` | The number of bytes read, or `https://developer.android.com/reference/androidx/media3/common/C#RESULT_END_OF_INPUT()` if the input has ended. This may be less than `length` because the end of the input (or available data) was reached, the method was interrupted, or the operation was aborted early for another reason. |

| Throws |
|---|---|
| `https://developer.android.com/reference/java/io/IOException.html` | If an error occurs reading from the input. |