src/audio/SDL_audio_c.h
author Ryan C. Gordon
Sat, 05 Nov 2016 02:34:38 -0400
changeset 10575 bb99dede0675
parent 10239 04cda108b406
child 10737 3406a0f8b041
permissions -rw-r--r--
Reworked audio converter code.

This no longer uses a script to generate code for every possible type
conversion or resampler. This caused a bloat in binary size and and compile
times. Now we use a handful of more generic functions and assume staying in
the CPU cache is the most important thing anyhow.

This shrinks the size of the final build (in this case: macOS X amd64, -Os to
optimize for size) by 15%. When compiling on a single core, build times drop
by about 15% too (although the previous cost was largely hidden by multicore
builds).
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>
     4 
     5   This software is provided 'as-is', without any express or implied
     6   warranty.  In no event will the authors be held liable for any damages
     7   arising from the use of this software.
     8 
     9   Permission is granted to anyone to use this software for any purpose,
    10   including commercial applications, and to alter it and redistribute it
    11   freely, subject to the following restrictions:
    12 
    13   1. The origin of this software must not be misrepresented; you must not
    14      claim that you wrote the original software. If you use this software
    15      in a product, an acknowledgment in the product documentation would be
    16      appreciated but is not required.
    17   2. Altered source versions must be plainly marked as such, and must not be
    18      misrepresented as being the original software.
    19   3. This notice may not be removed or altered from any source distribution.
    20 */
    21 #include "../SDL_internal.h"
    22 
    23 #ifndef DEBUG_CONVERT
    24 #define DEBUG_CONVERT 0
    25 #endif
    26 
    27 #if DEBUG_CONVERT
    28 #define LOG_DEBUG_CONVERT(from, to) fprintf(stderr, "Converting %s to %s.\n", from, to);
    29 #else
    30 #define LOG_DEBUG_CONVERT(from, to)
    31 #endif
    32 
    33 /* Functions and variables exported from SDL_audio.c for SDL_sysaudio.c */
    34 
    35 /* Functions to get a list of "close" audio formats */
    36 extern SDL_AudioFormat SDL_FirstAudioFormat(SDL_AudioFormat format);
    37 extern SDL_AudioFormat SDL_NextAudioFormat(void);
    38 
    39 /* Function to calculate the size and silence for a SDL_AudioSpec */
    40 extern void SDL_CalculateAudioSpec(SDL_AudioSpec * spec);
    41 
    42 void SDLCALL SDL_Convert_S8_to_F32(SDL_AudioCVT *cvt, SDL_AudioFormat format);
    43 void SDLCALL SDL_Convert_U8_to_F32(SDL_AudioCVT *cvt, SDL_AudioFormat format);
    44 void SDLCALL SDL_Convert_S16_to_F32(SDL_AudioCVT *cvt, SDL_AudioFormat format);
    45 void SDLCALL SDL_Convert_U16_to_F32(SDL_AudioCVT *cvt, SDL_AudioFormat format);
    46 void SDLCALL SDL_Convert_S32_to_F32(SDL_AudioCVT *cvt, SDL_AudioFormat format);
    47 void SDLCALL SDL_Convert_F32_to_S8(SDL_AudioCVT *cvt, SDL_AudioFormat format);
    48 void SDLCALL SDL_Convert_F32_to_U8(SDL_AudioCVT *cvt, SDL_AudioFormat format);
    49 void SDLCALL SDL_Convert_F32_to_S16(SDL_AudioCVT *cvt, SDL_AudioFormat format);
    50 void SDLCALL SDL_Convert_F32_to_U16(SDL_AudioCVT *cvt, SDL_AudioFormat format);
    51 void SDLCALL SDL_Convert_F32_to_S32(SDL_AudioCVT *cvt, SDL_AudioFormat format);
    52 void SDL_Upsample_Arbitrary(SDL_AudioCVT *cvt, const int channels);
    53 void SDL_Downsample_Arbitrary(SDL_AudioCVT *cvt, const int channels);
    54 void SDL_Upsample_x2(SDL_AudioCVT *cvt, const int channels);
    55 void SDL_Upsample_x4(SDL_AudioCVT *cvt, const int channels);
    56 void SDL_Downsample_Multiple(SDL_AudioCVT *cvt, const int multiple, const int channels);
    57 
    58 /* vi: set ts=4 sw=4 expandtab: */