1 /*
2  * Copyright (C) 2020 Linux Studio Plugins Project <https://lsp-plug.in/>
3  *           (C) 2020 Vladimir Sadovnikov <sadko4u@gmail.com>
4  *
5  * This file is part of lsp-plugins
6  * Created on: 24 марта 2016 г.
7  *
8  * lsp-plugins is free software: you can redistribute it and/or modify
9  * it under the terms of the GNU Lesser General Public License as published by
10  * the Free Software Foundation, either version 3 of the License, or
11  * any later version.
12  *
13  * lsp-plugins is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public License
19  * along with lsp-plugins. If not, see <https://www.gnu.org/licenses/>.
20  */
21 
22 #include <core/fade.h>
23 
24 namespace lsp
25 {
fade_in(float * dst,const float * src,size_t fade_len,size_t buf_len)26     void fade_in(float *dst, const float *src, size_t fade_len, size_t buf_len)
27     {
28         if ((fade_len <= 0) || (buf_len <= 0))
29             return;
30 
31         float k = 1.0f / fade_len;
32         if (fade_len > buf_len)
33             fade_len = buf_len;
34 
35         for (size_t i=0; i < fade_len; ++i)
36             dst[i] = src[i] * i * k;
37     }
38 
fade_out(float * dst,const float * src,size_t fade_len,size_t buf_len)39     void fade_out(float *dst, const float *src, size_t fade_len, size_t buf_len)
40     {
41         if ((fade_len <= 0) || (buf_len <= 0))
42             return;
43 
44         float k = 1.0f / fade_len;
45         if (fade_len > buf_len)
46             fade_len = buf_len;
47         else
48         {
49             src     = &src[buf_len - fade_len];
50             dst     = &dst[buf_len - fade_len];
51         }
52 
53         for (size_t i=fade_len; i > 0; )
54             *(dst++) = *(src++) * ((--i) * k);
55     }
56 }
57 
58