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* Copyright (C) 2009 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
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
#ifndef DATA_SOURCE_H_
#define DATA_SOURCE_H_
#include <sys/types.h>
#include <media/stagefright/foundation/ADebug.h>
#include <media/stagefright/MediaErrors.h>
#include <utils/Errors.h>
#include <utils/KeyedVector.h>
#include <utils/List.h>
#include <utils/RefBase.h>
#include <utils/threads.h>
#include <drm/DrmManagerClient.h>
namespace android {
struct AMessage;
struct AString;
class IDataSource;
struct IMediaHTTPService;
class String8;
struct HTTPBase;
class DataSource : public RefBase {
enum Flags {
kWantsPrefetching = 1,
kStreamedFromLocalHost = 2,
kIsCachingDataSource = 4,
kIsHTTPBasedSource = 8,
kIsLocalFileSource = 16,
static sp<DataSource> CreateFromURI(
const sp<IMediaHTTPService> &httpService,
const char *uri,
const KeyedVector<String8, String8> *headers = NULL,
String8 *contentType = NULL,
HTTPBase *httpSource = NULL);
static sp<DataSource> CreateMediaHTTP(const sp<IMediaHTTPService> &httpService);
static sp<DataSource> CreateFromIDataSource(const sp<IDataSource> &source);
static sp<DataSource> CreateFromFd(int fd, int64_t offset, int64_t length);
DataSource() {}
virtual status_t initCheck() const = 0;
// Returns the number of bytes read, or -1 on failure. It's not an error if
// this returns zero; it just means the given offset is equal to, or
// beyond, the end of the source.
virtual ssize_t readAt(off64_t offset, void *data, size_t size) = 0;
// Convenience methods:
bool getUInt16(off64_t offset, uint16_t *x);
bool getUInt24(off64_t offset, uint32_t *x); // 3 byte int, returned as a 32-bit int
bool getUInt32(off64_t offset, uint32_t *x);
bool getUInt64(off64_t offset, uint64_t *x);
// Reads in "count" entries of type T into vector *x.
// Returns true if "count" entries can be read.
// If fewer than "count" entries can be read, return false. In this case,
// the output vector *x will still have those entries that were read. Call
// x->size() to obtain the number of entries read.
// The optional parameter chunkSize specifies how many entries should be
// read from the data source at one time into a temporary buffer. Increasing
// chunkSize can improve the performance at the cost of extra memory usage.
// The default value for chunkSize is set to read at least 4k bytes at a
// time, depending on sizeof(T).
template <typename T>
bool getVector(off64_t offset, Vector<T>* x, size_t count,
size_t chunkSize = (4095 / sizeof(T)) + 1);
virtual status_t getSize(off64_t *size);
virtual uint32_t flags() {
return 0;
virtual String8 toString() {
return String8("<unspecified>");
virtual status_t reconnectAtOffset(off64_t /*offset*/) {
// for DRM
virtual sp<DecryptHandle> DrmInitialization(const char * /*mime*/ = NULL) {
return NULL;
virtual void getDrmInfo(sp<DecryptHandle> &/*handle*/, DrmManagerClient ** /*client*/) {};
virtual String8 getUri() {
return String8();
virtual String8 getMIMEType() const;
virtual void close() {};
// creates an IDataSource wrapper to the DataSource.
virtual sp<IDataSource> asIDataSource();
// returns a pointer to IDataSource if it is wrapped.
virtual sp<IDataSource> getIDataSource() const;
virtual ~DataSource() {}
DataSource(const DataSource &);
DataSource &operator=(const DataSource &);
template <typename T>
bool DataSource::getVector(off64_t offset, Vector<T>* x, size_t count,
size_t chunkSize)
if (chunkSize == 0) {
return false;
if (count == 0) {
return true;
T tmp[chunkSize];
ssize_t numBytesRead;
size_t numBytesPerChunk = chunkSize * sizeof(T);
size_t i;
for (i = 0; i + chunkSize < count; i += chunkSize) {
// This loops is executed when more than chunkSize records need to be
// read.
numBytesRead = this->readAt(offset, (void*)&tmp, numBytesPerChunk);
if (numBytesRead == -1) { // If readAt() returns -1, there is an error.
return false;
if (numBytesRead < numBytesPerChunk) {
// This case is triggered when the stream ends before the whole
// chunk is read.
x->appendArray(tmp, (size_t)numBytesRead / sizeof(T));
return false;
x->appendArray(tmp, chunkSize);
offset += numBytesPerChunk;
// There are (count - i) more records to read.
// Right now, (count - i) <= chunkSize.
// We do the same thing as above, but with chunkSize replaced by count - i.
numBytesRead = this->readAt(offset, (void*)&tmp, (count - i) * sizeof(T));
if (numBytesRead == -1) {
return false;
x->appendArray(tmp, (size_t)numBytesRead / sizeof(T));
return x->size() == count;
} // namespace android
#endif // DATA_SOURCE_H_