include/common/SC_fftlib.h

   1 /*
   2 SC_fftlib.h
   3 An interface to abstract over different FFT libraries, for SuperCollider 3.
   4 Copyright (c) 2008 Dan Stowell. All rights reserved.
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
  19
  20 */
  21
  22 #ifndef _SC_fftlib_
  23 #define _SC_fftlib_
  24
  25 #include <string.h>
  26
  27 // These specify the min & max FFT sizes expected (used when creating windows, also allocating some other arrays).
  28 #define SC_FFT_MINSIZE 8
  29 #define SC_FFT_LOG2_MINSIZE 3
  30 #define SC_FFT_MAXSIZE 8192
  31 #define SC_FFT_LOG2_MAXSIZE 13
  32
  33
  34 // Note that things like *fftWindow actually allow for other sizes, to be created on user request.
  35 #define SC_FFT_ABSOLUTE_MAXSIZE 2147483648
  36 #define SC_FFT_LOG2_ABSOLUTE_MAXSIZE 31
  37 #define SC_FFT_LOG2_ABSOLUTE_MAXSIZE_PLUS1 32
  38
  39 struct scfft;
  40
  41 class SCFFT_Allocator
  42 {
  43 public:
  44         virtual void* alloc(size_t size) = 0;
  45         virtual void free(void* ptr) = 0;
  46 };
  47
  48 enum SCFFT_Direction
  49 {
  50         kForward = 1,
  51         kBackward = 0
  52 };
  53
  54 // These values are referred to from SC lang as well as in the following code - do not rearrange!
  55 enum SCFFT_WindowFunction
  56 {
  57         kRectWindow = -1,
  58         kSineWindow = 0,
  59         kHannWindow = 1
  60 };
  61
  62 ////////////////////////////////////////////////////////////////////////////////////////////////////
  63 // Functions
  64
  65 // To initialise a specific FFT, ensure your input and output buffers exist. Internal data structures
  66 // will be allocated using the alloc object,
  67 // Both "fullsize" and "winsize" should be powers of two (this is not checked internally).
  68 scfft * scfft_create(size_t fullsize, size_t winsize, SCFFT_WindowFunction wintype,
  69                                          float *indata, float *outdata, SCFFT_Direction forward, SCFFT_Allocator & alloc);
  70
  71 // These two will take data from indata, use trbuf to process it, and put their results in outdata.
  72 void scfft_dofft(scfft *f);
  73 void scfft_doifft(scfft *f);
  74
  75 // destroy any resources held internally.
  76 void scfft_destroy(scfft *f, SCFFT_Allocator & alloc);
  77
  78 #endif