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/*
* Copyrightm (C) 2010 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 "AudioCodec.h"
extern "C" {
#include "gsm.h"
}
namespace {
class GsmCodec : public AudioCodec
{
public:
GsmCodec() {
mEncode = gsm_create();
mDecode = gsm_create();
}
~GsmCodec() {
if (mEncode) {
gsm_destroy(mEncode);
}
if (mDecode) {
gsm_destroy(mDecode);
}
}
int set(int sampleRate, const char *fmtp) {
return (sampleRate == 8000 && mEncode && mDecode) ? 160 : -1;
}
int encode(void *payload, int16_t *samples);
int decode(int16_t *samples, int count, void *payload, int length);
private:
gsm mEncode;
gsm mDecode;
};
int GsmCodec::encode(void *payload, int16_t *samples)
{
gsm_encode(mEncode, samples, (unsigned char *)payload);
return 33;
}
int GsmCodec::decode(int16_t *samples, int count, void *payload, int length)
{
unsigned char *bytes = (unsigned char *)payload;
int n = 0;
while (n + 160 <= count && length >= 33 &&
gsm_decode(mDecode, bytes, &samples[n]) == 0) {
n += 160;
length -= 33;
bytes += 33;
}
return n;
}
} // namespace
AudioCodec *newGsmCodec()
{
return new GsmCodec;
}
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