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      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 //#define LOG_NDEBUG 0
     18 #define LOG_TAG "MidiIoWrapper"
     19 #include <utils/Log.h>
     20 #include <utils/RefBase.h>
     21 
     22 #include <sys/stat.h>
     23 #include <fcntl.h>
     24 
     25 #include <media/MidiIoWrapper.h>
     26 #include <media/MediaExtractorPluginApi.h>
     27 
     28 static int readAt(void *handle, void *buffer, int pos, int size) {
     29     return ((android::MidiIoWrapper*)handle)->readAt(buffer, pos, size);
     30 }
     31 static int size(void *handle) {
     32     return ((android::MidiIoWrapper*)handle)->size();
     33 }
     34 
     35 namespace android {
     36 
     37 MidiIoWrapper::MidiIoWrapper(const char *path) {
     38     ALOGV("MidiIoWrapper(%s)", path);
     39     mFd = open(path, O_RDONLY | O_LARGEFILE);
     40     mBase = 0;
     41     mLength = lseek(mFd, 0, SEEK_END);
     42     mDataSource = nullptr;
     43 }
     44 
     45 MidiIoWrapper::MidiIoWrapper(int fd, off64_t offset, int64_t size) {
     46     ALOGV("MidiIoWrapper(fd=%d)", fd);
     47     mFd = fd < 0 ? -1 : dup(fd);
     48     mBase = offset;
     49     mLength = size;
     50     mDataSource = nullptr;
     51 }
     52 
     53 class DataSourceUnwrapper : public DataSourceBase {
     54 
     55 public:
     56     explicit DataSourceUnwrapper(CDataSource *csource) {
     57         mSource = csource;
     58     }
     59 
     60     virtual ~DataSourceUnwrapper() {}
     61 
     62     virtual status_t initCheck() const { return OK; }
     63 
     64     // Returns the number of bytes read, or -1 on failure. It's not an error if
     65     // this returns zero; it just means the given offset is equal to, or
     66     // beyond, the end of the source.
     67     virtual ssize_t readAt(off64_t offset, void *data, size_t size) {
     68         return mSource->readAt(mSource->handle, offset, data, size);
     69     }
     70 
     71     // May return ERROR_UNSUPPORTED.
     72     virtual status_t getSize(off64_t *size) {
     73         return mSource->getSize(mSource->handle, size);
     74     }
     75 
     76     virtual bool getUri(char * /*uriString*/, size_t /*bufferSize*/) {
     77         return false;
     78     }
     79 
     80     virtual uint32_t flags() {
     81         return 0;
     82     }
     83 
     84     virtual void close() {};
     85 private:
     86     CDataSource *mSource;
     87 };
     88 
     89 MidiIoWrapper::MidiIoWrapper(CDataSource *csource) {
     90     ALOGV("MidiIoWrapper(CDataSource)");
     91     mFd = -1;
     92     mBase = 0;
     93     mDataSource = new DataSourceUnwrapper(csource);
     94     off64_t l;
     95     if (mDataSource->getSize(&l) == OK) {
     96         mLength = l;
     97     } else {
     98         mLength = 0;
     99     }
    100 }
    101 
    102 MidiIoWrapper::~MidiIoWrapper() {
    103     ALOGV("~MidiIoWrapper");
    104     if (mFd >= 0) {
    105         close(mFd);
    106     }
    107     delete mDataSource;
    108 }
    109 
    110 int MidiIoWrapper::readAt(void *buffer, int offset, int size) {
    111     ALOGV("readAt(%p, %d, %d)", buffer, offset, size);
    112 
    113     if (mDataSource != NULL) {
    114         return mDataSource->readAt(offset, buffer, size);
    115     }
    116     if (mFd < 0) {
    117         errno = EBADF;
    118         return -1; // as per failed read.
    119     }
    120     lseek(mFd, mBase + offset, SEEK_SET);
    121     if (offset + size > mLength) {
    122         size = mLength - offset;
    123     }
    124     return read(mFd, buffer, size);
    125 }
    126 
    127 int MidiIoWrapper::size() {
    128     ALOGV("size() = %d", int(mLength));
    129     return mLength;
    130 }
    131 
    132 EAS_FILE_LOCATOR MidiIoWrapper::getLocator() {
    133     mEasFile.handle = this;
    134     mEasFile.readAt = ::readAt;
    135     mEasFile.size = ::size;
    136     return &mEasFile;
    137 }
    138 
    139 }  // namespace android
    140