1 /*
2  * Copyright (C) 2020 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 #include <stddef.h>
18 #include <stdint.h>
19 
DecodeMLaw(int16_t * out,const uint8_t * in,size_t inSize)20 void DecodeMLaw(int16_t *out, const uint8_t *in, size_t inSize) {
21   if (out != nullptr && in != nullptr) {
22     while (inSize > 0) {
23       inSize--;
24       int32_t x = *in++;
25 
26       int32_t mantissa = ~x;
27       int32_t exponent = (mantissa >> 4) & 7;
28       int32_t segment = exponent + 1;
29       mantissa &= 0x0f;
30 
31       int32_t step = 4 << segment;
32 
33       int32_t abs = (0x80l << exponent) + step * mantissa + step / 2 - 4 * 33;
34 
35       *out++ = (x < 0x80) ? -abs : abs;
36     }
37   }
38 }
39