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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
*
* 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.
*/
//#define LOG_NDEBUG 0
#define LOG_TAG "Metadata"
#include <utils/Log.h>
#include <sys/types.h>
#include <media/Metadata.h>
#include <binder/Parcel.h>
#include <utils/Errors.h>
#include <utils/RefBase.h>
// This file contains code to serialize Metadata triples (key, type,
// value) into a parcel. The Parcel is destinated to be decoded by the
// Metadata.java class.
namespace {
// All these constants below must be kept in sync with Metadata.java.
enum MetadataId {
FIRST_SYSTEM_ID = 1,
LAST_SYSTEM_ID = 31,
FIRST_CUSTOM_ID = 8192
};
// Types
enum Types {
STRING_VAL = 1,
INTEGER_VAL,
BOOLEAN_VAL,
LONG_VAL,
DOUBLE_VAL,
DATE_VAL,
BYTE_ARRAY_VAL,
};
const size_t kRecordHeaderSize = 3 * sizeof(int32_t);
const int32_t kMetaMarker = 0x4d455441; // 'M' 'E' 'T' 'A'
} // anonymous namespace
namespace android {
namespace media {
Metadata::Metadata(Parcel *p)
:mData(p),
mBegin(p->dataPosition()) { }
Metadata::~Metadata() { }
void Metadata::resetParcel()
{
mData->setDataPosition(mBegin);
}
// Update the 4 bytes int at the beginning of the parcel which holds
// the number of bytes written so far.
void Metadata::updateLength()
{
const size_t end = mData->dataPosition();
mData->setDataPosition(mBegin);
mData->writeInt32(end - mBegin);
mData->setDataPosition(end);
}
// Write the header. The java layer will look for the marker.
bool Metadata::appendHeader()
{
bool ok = true;
// Placeholder for the length of the metadata
ok = ok && mData->writeInt32(-1) == OK;
ok = ok && mData->writeInt32(kMetaMarker) == OK;
return ok;
}
bool Metadata::appendBool(int key, bool val)
{
if (!checkKey(key)) {
return false;
}
const size_t begin = mData->dataPosition();
bool ok = true;
// 4 int32s: size, key, type, value.
ok = ok && mData->writeInt32(4 * sizeof(int32_t)) == OK;
ok = ok && mData->writeInt32(key) == OK;
ok = ok && mData->writeInt32(BOOLEAN_VAL) == OK;
ok = ok && mData->writeInt32(val ? 1 : 0) == OK;
if (!ok) {
mData->setDataPosition(begin);
}
return ok;
}
bool Metadata::appendInt32(int key, int32_t val)
{
if (!checkKey(key)) {
return false;
}
const size_t begin = mData->dataPosition();
bool ok = true;
// 4 int32s: size, key, type, value.
ok = ok && mData->writeInt32(4 * sizeof(int32_t)) == OK;
ok = ok && mData->writeInt32(key) == OK;
ok = ok && mData->writeInt32(INTEGER_VAL) == OK;
ok = ok && mData->writeInt32(val) == OK;
if (!ok) {
mData->setDataPosition(begin);
}
return ok;
}
// Check the key (i.e metadata id) is valid if it is a system one.
// Loop over all the exiting ones in the Parcel to check for duplicate
// (not allowed).
bool Metadata::checkKey(int key)
{
if (key < FIRST_SYSTEM_ID ||
(LAST_SYSTEM_ID < key && key < FIRST_CUSTOM_ID)) {
ALOGE("Bad key %d", key);
return false;
}
size_t curr = mData->dataPosition();
// Loop over the keys to check if it has been used already.
mData->setDataPosition(mBegin);
bool error = false;
size_t left = curr - mBegin;
while (left > 0) {
size_t pos = mData->dataPosition();
size_t size = mData->readInt32();
if (size < kRecordHeaderSize || size > left) {
error = true;
break;
}
if (mData->readInt32() == key) {
ALOGE("Key exists already %d", key);
error = true;
break;
}
mData->setDataPosition(pos + size);
left -= size;
}
mData->setDataPosition(curr);
return !error;
}
} // namespace android::media
} // namespace android
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