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author | Aki <please@ignore.pl> | 2021-10-01 23:46:47 +0200 |
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committer | Aki <please@ignore.pl> | 2021-10-01 23:46:47 +0200 |
commit | ddd76aa4e1571c8d5965709db5c3cd47a89c9a38 (patch) | |
tree | 4e07bfaebede6531a70984fdebc855bca52f394a /vorbis/lib/lookup.c | |
parent | 3a507e08b1d4e5970b27401a7e6517570d529400 (diff) | |
parent | c2d2c3551501110fddd78674d5435bfaa70382a3 (diff) | |
download | starshatter-ddd76aa4e1571c8d5965709db5c3cd47a89c9a38.zip starshatter-ddd76aa4e1571c8d5965709db5c3cd47a89c9a38.tar.gz starshatter-ddd76aa4e1571c8d5965709db5c3cd47a89c9a38.tar.bz2 |
Project is now built with CMake
Diffstat (limited to 'vorbis/lib/lookup.c')
-rw-r--r-- | vorbis/lib/lookup.c | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/vorbis/lib/lookup.c b/vorbis/lib/lookup.c new file mode 100644 index 0000000..1cc1f88 --- /dev/null +++ b/vorbis/lib/lookup.c @@ -0,0 +1,93 @@ +/******************************************************************** + * * + * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. * + * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS * + * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * + * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * + * * + * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009 * + * by the Xiph.Org Foundation http://www.xiph.org/ * + * * + ******************************************************************** + + function: lookup based functions + + ********************************************************************/ + +#include <math.h> +#include "lookup.h" +#include "lookup_data.h" +#include "os.h" +#include "misc.h" + +#ifdef FLOAT_LOOKUP + +/* interpolated lookup based cos function, domain 0 to PI only */ +float vorbis_coslook(float a){ + double d=a*(.31830989*(float)COS_LOOKUP_SZ); + int i=vorbis_ftoi(d-.5); + + return COS_LOOKUP[i]+ (d-i)*(COS_LOOKUP[i+1]-COS_LOOKUP[i]); +} + +/* interpolated 1./sqrt(p) where .5 <= p < 1. */ +float vorbis_invsqlook(float a){ + double d=a*(2.f*(float)INVSQ_LOOKUP_SZ)-(float)INVSQ_LOOKUP_SZ; + int i=vorbis_ftoi(d-.5f); + return INVSQ_LOOKUP[i]+ (d-i)*(INVSQ_LOOKUP[i+1]-INVSQ_LOOKUP[i]); +} + +/* interpolated 1./sqrt(p) where .5 <= p < 1. */ +float vorbis_invsq2explook(int a){ + return INVSQ2EXP_LOOKUP[a-INVSQ2EXP_LOOKUP_MIN]; +} + +#include <stdio.h> +/* interpolated lookup based fromdB function, domain -140dB to 0dB only */ +float vorbis_fromdBlook(float a){ + int i=vorbis_ftoi(a*((float)(-(1<<FROMdB2_SHIFT)))-.5f); + return (i<0)?1.f: + ((i>=(FROMdB_LOOKUP_SZ<<FROMdB_SHIFT))?0.f: + FROMdB_LOOKUP[i>>FROMdB_SHIFT]*FROMdB2_LOOKUP[i&FROMdB2_MASK]); +} + +#endif + +#ifdef INT_LOOKUP +/* interpolated 1./sqrt(p) where .5 <= a < 1. (.100000... to .111111...) in + 16.16 format + + returns in m.8 format */ +long vorbis_invsqlook_i(long a,long e){ + long i=(a&0x7fff)>>(INVSQ_LOOKUP_I_SHIFT-1); + long d=(a&INVSQ_LOOKUP_I_MASK)<<(16-INVSQ_LOOKUP_I_SHIFT); /* 0.16 */ + long val=INVSQ_LOOKUP_I[i]- /* 1.16 */ + (((INVSQ_LOOKUP_I[i]-INVSQ_LOOKUP_I[i+1])* /* 0.16 */ + d)>>16); /* result 1.16 */ + + e+=32; + if(e&1)val=(val*5792)>>13; /* multiply val by 1/sqrt(2) */ + e=(e>>1)-8; + + return(val>>e); +} + +/* interpolated lookup based fromdB function, domain -140dB to 0dB only */ +/* a is in n.12 format */ +float vorbis_fromdBlook_i(long a){ + int i=(-a)>>(12-FROMdB2_SHIFT); + return (i<0)?1.f: + ((i>=(FROMdB_LOOKUP_SZ<<FROMdB_SHIFT))?0.f: + FROMdB_LOOKUP[i>>FROMdB_SHIFT]*FROMdB2_LOOKUP[i&FROMdB2_MASK]); +} + +/* interpolated lookup based cos function, domain 0 to PI only */ +/* a is in 0.16 format, where 0==0, 2^^16-1==PI, return 0.14 */ +long vorbis_coslook_i(long a){ + int i=a>>COS_LOOKUP_I_SHIFT; + int d=a&COS_LOOKUP_I_MASK; + return COS_LOOKUP_I[i]- ((d*(COS_LOOKUP_I[i]-COS_LOOKUP_I[i+1]))>> + COS_LOOKUP_I_SHIFT); +} + +#endif |