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/*
* Copyright (C) 2012 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 "SkipCutBuffer"
#include <utils/Log.h>
#include <media/stagefright/foundation/ADebug.h>
#include <media/stagefright/MediaBuffer.h>
#include <media/stagefright/SkipCutBuffer.h>
namespace android {
SkipCutBuffer::SkipCutBuffer(int32_t skip, int32_t cut, int32_t output_size) {
mFrontPadding = skip;
mBackPadding = cut;
mWriteHead = 0;
mReadHead = 0;
mCapacity = cut + output_size;
mCutBuffer = new char[mCapacity];
ALOGV("skipcutbuffer %d %d %d", skip, cut, mCapacity);
}
SkipCutBuffer::~SkipCutBuffer() {
delete[] mCutBuffer;
}
void SkipCutBuffer::submit(MediaBuffer *buffer) {
int32_t offset = buffer->range_offset();
int32_t buflen = buffer->range_length();
// drop the initial data from the buffer if needed
if (mFrontPadding > 0) {
// still data left to drop
int32_t to_drop = (buflen < mFrontPadding) ? buflen : mFrontPadding;
offset += to_drop;
buflen -= to_drop;
buffer->set_range(offset, buflen);
mFrontPadding -= to_drop;
}
// append data to cutbuffer
char *src = ((char*) buffer->data()) + offset;
write(src, buflen);
// the mediabuffer is now empty. Fill it from cutbuffer, always leaving
// at least mBackPadding bytes in the cutbuffer
char *dst = (char*) buffer->data();
size_t copied = read(dst, buffer->size());
buffer->set_range(0, copied);
}
void SkipCutBuffer::clear() {
mWriteHead = mReadHead = 0;
}
void SkipCutBuffer::write(const char *src, size_t num) {
int32_t sizeused = (mWriteHead - mReadHead);
if (sizeused < 0) sizeused += mCapacity;
// everything must fit
CHECK_GE((mCapacity - size_t(sizeused)), num);
size_t copyfirst = (mCapacity - mWriteHead);
if (copyfirst > num) copyfirst = num;
if (copyfirst) {
memcpy(mCutBuffer + mWriteHead, src, copyfirst);
num -= copyfirst;
src += copyfirst;
mWriteHead += copyfirst;
CHECK_LE(mWriteHead, mCapacity);
if (mWriteHead == mCapacity) mWriteHead = 0;
if (num) {
memcpy(mCutBuffer, src, num);
mWriteHead += num;
}
}
}
size_t SkipCutBuffer::read(char *dst, size_t num) {
int32_t available = (mWriteHead - mReadHead);
if (available < 0) available += mCapacity;
available -= mBackPadding;
if (available <=0) {
return 0;
}
if (available < num) {
num = available;
}
size_t copyfirst = (mCapacity - mReadHead);
if (copyfirst > num) copyfirst = num;
if (copyfirst) {
memcpy(dst, mCutBuffer + mReadHead, copyfirst);
num -= copyfirst;
dst += copyfirst;
mReadHead += copyfirst;
CHECK_LE(mReadHead, mCapacity);
if (mReadHead == mCapacity) mReadHead = 0;
if (num) {
memcpy(dst, mCutBuffer, num);
mReadHead += num;
}
}
return available;
}
size_t SkipCutBuffer::size() {
int32_t available = (mWriteHead - mReadHead);
if (available < 0) available += mCapacity;
return available;
}
} // namespace android
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