media/libstagefright/DataSource.cpp

/*
 * 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
 *
 *      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.
 */

#include <media/stagefright/DataSource.h>
#include <media/stagefright/MediaErrors.h>
#include <media/stagefright/MP3Extractor.h>
#include <media/stagefright/MPEG4Extractor.h>
#include <utils/String8.h>

namespace android {

bool DataSource::getUInt16(off_t offset, uint16_t *x) {
    *x = 0;

    uint8_t byte[2];
    if (read_at(offset, byte, 2) != 2) {
        return false;
    }

    *x = (byte[0] << 8) | byte[1];

    return true;
}

status_t DataSource::getSize(off_t *size) {
    *size = 0;

    return ERROR_UNSUPPORTED;
}

////////////////////////////////////////////////////////////////////////////////

Mutex DataSource::gSnifferMutex;
List<DataSource::SnifferFunc> DataSource::gSniffers;

bool DataSource::sniff(String8 *mimeType, float *confidence) {
    *mimeType = "";
    *confidence = 0.0f;

    Mutex::Autolock autoLock(gSnifferMutex);
    for (List<SnifferFunc>::iterator it = gSniffers.begin();
         it != gSniffers.end(); ++it) {
        String8 newMimeType;
        float newConfidence;
        if ((*it)(this, &newMimeType, &newConfidence)) {
            if (newConfidence > *confidence) {
                *mimeType = newMimeType;
                *confidence = newConfidence;
            }
        }
    }

    return *confidence > 0.0;
}

// static
void DataSource::RegisterSniffer(SnifferFunc func) {
    Mutex::Autolock autoLock(gSnifferMutex);

    for (List<SnifferFunc>::iterator it = gSniffers.begin();
         it != gSniffers.end(); ++it) {
        if (*it == func) {
            return;
        }
    }

    gSniffers.push_back(func);
}

// static
void DataSource::RegisterDefaultSniffers() {
    RegisterSniffer(SniffMP3);
    RegisterSniffer(SniffMPEG4);
}

}  // namespace android