add necessary #includes in headers
[libav.git] / libavcodec / acelp_math.h
1 /*
2 * Various fixed-point math operations
3 *
4 * Copyright (c) 2008 Vladimir Voroshilov
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg 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 GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #ifndef FFMPEG_ACELP_MATH_H
24 #define FFMPEG_ACELP_MATH_H
25
26 #include <stdint.h>
27
28 /**
29 * \brief fixed-point implementation of cosine in [0; PI) domain
30 * \param arg fixed-point cosine argument, 0 <= arg < 0x4000
31 *
32 * \return value of (1<<15) * cos(arg * PI / (1<<14)), -0x8000 <= result <= 0x7fff
33 */
34 int16_t ff_cos(uint16_t arg);
35
36 /**
37 * \brief fixed-point implementation of exp2(x) in [0; 1] domain
38 * \param power argument to exp2, 0 <= power <= 0x7fff
39 *
40 * \return value of (1<<20) * exp2(power / (1<<15))
41 * 0x8000c <= result <= 0xfffea
42 */
43 int ff_exp2(uint16_t power);
44
45 /**
46 * \brief Calculates log2(x)
47 * \param value function argument, 0 < value <= 7fff ffff
48 *
49 * \return value of (1<<15) * log2(value)
50 */
51 int ff_log2(uint32_t value);
52
53 /**
54 * \brief Calculates sum of array element multiplications
55 * \param speech input data array
56 * \param length number of elements
57 * \param offset offset for calculation of sum of s[i]*s[i+offset]
58 * \param shift right shift by this value will be done before multiplication
59 *
60 * \return sum of multiplications
61 *
62 * \note array must be at least length+offset long!
63 */
64 static int sum_of_squares(const int16_t* speech, int length, int offset, int shift)
65 {
66 const int16_t* speech_end;
67 int sum = 0;
68
69 for(speech_end=speech+length; speech<speech_end; speech++)
70 sum += (speech[0] * speech[offset]) >> shift;
71
72 return sum;
73 }
74
75 #endif // FFMPEG_ACELP_MATH_H