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+/* Copyright (c) 2007-2008 CSIRO
+ Copyright (c) 2007-2009 Xiph.Org Foundation
+ Copyright (c) 2007-2009 Timothy B. Terriberry
+ Written by Timothy B. Terriberry and Jean-Marc Valin */
+/*
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ - Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+
+ - Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+ OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "os_support.h"
+#include "cwrs.h"
+#include "mathops.h"
+#include "arch.h"
+
+#ifdef CUSTOM_MODES
+
+/*Guaranteed to return a conservatively large estimate of the binary logarithm
+ with frac bits of fractional precision.
+ Tested for all possible 32-bit inputs with frac=4, where the maximum
+ overestimation is 0.06254243 bits.*/
+int log2_frac(opus_uint32 val, int frac)
+{
+ int l;
+ l=EC_ILOG(val);
+ if(val&(val-1)){
+ /*This is (val>>l-16), but guaranteed to round up, even if adding a bias
+ before the shift would cause overflow (e.g., for 0xFFFFxxxx).
+ Doesn't work for val=0, but that case fails the test above.*/
+ if(l>16)val=((val-1)>>(l-16))+1;
+ else val<<=16-l;
+ l=(l-1)<<frac;
+ /*Note that we always need one iteration, since the rounding up above means
+ that we might need to adjust the integer part of the logarithm.*/
+ do{
+ int b;
+ b=(int)(val>>16);
+ l+=b<<frac;
+ val=(val+b)>>b;
+ val=(val*val+0x7FFF)>>15;
+ }
+ while(frac-->0);
+ /*If val is not exactly 0x8000, then we have to round up the remainder.*/
+ return l+(val>0x8000);
+ }
+ /*Exact powers of two require no rounding.*/
+ else return (l-1)<<frac;
+}
+#endif
+
+#ifndef SMALL_FOOTPRINT
+
+#define MASK32 (0xFFFFFFFF)
+
+/*INV_TABLE[i] holds the multiplicative inverse of (2*i+1) mod 2**32.*/
+static const opus_uint32 INV_TABLE[53]={
+ 0x00000001,0xAAAAAAAB,0xCCCCCCCD,0xB6DB6DB7,
+ 0x38E38E39,0xBA2E8BA3,0xC4EC4EC5,0xEEEEEEEF,
+ 0xF0F0F0F1,0x286BCA1B,0x3CF3CF3D,0xE9BD37A7,
+ 0xC28F5C29,0x684BDA13,0x4F72C235,0xBDEF7BDF,
+ 0x3E0F83E1,0x8AF8AF8B,0x914C1BAD,0x96F96F97,
+ 0xC18F9C19,0x2FA0BE83,0xA4FA4FA5,0x677D46CF,
+ 0x1A1F58D1,0xFAFAFAFB,0x8C13521D,0x586FB587,
+ 0xB823EE09,0xA08AD8F3,0xC10C9715,0xBEFBEFBF,
+ 0xC0FC0FC1,0x07A44C6B,0xA33F128D,0xE327A977,
+ 0xC7E3F1F9,0x962FC963,0x3F2B3885,0x613716AF,
+ 0x781948B1,0x2B2E43DB,0xFCFCFCFD,0x6FD0EB67,
+ 0xFA3F47E9,0xD2FD2FD3,0x3F4FD3F5,0xD4E25B9F,
+ 0x5F02A3A1,0xBF5A814B,0x7C32B16D,0xD3431B57,
+ 0xD8FD8FD9,
+};
+
+/*Computes (_a*_b-_c)/(2*_d+1) when the quotient is known to be exact.
+ _a, _b, _c, and _d may be arbitrary so long as the arbitrary precision result
+ fits in 32 bits, but currently the table for multiplicative inverses is only
+ valid for _d<=52.*/
+static inline opus_uint32 imusdiv32odd(opus_uint32 _a,opus_uint32 _b,
+ opus_uint32 _c,int _d){
+ celt_assert(_d<=52);
+ return (_a*_b-_c)*INV_TABLE[_d]&MASK32;
+}
+
+/*Computes (_a*_b-_c)/_d when the quotient is known to be exact.
+ _d does not actually have to be even, but imusdiv32odd will be faster when
+ it's odd, so you should use that instead.
+ _a and _d are assumed to be small (e.g., _a*_d fits in 32 bits; currently the
+ table for multiplicative inverses is only valid for _d<=54).
+ _b and _c may be arbitrary so long as the arbitrary precision reuslt fits in
+ 32 bits.*/
+static inline opus_uint32 imusdiv32even(opus_uint32 _a,opus_uint32 _b,
+ opus_uint32 _c,int _d){
+ opus_uint32 inv;
+ int mask;
+ int shift;
+ int one;
+ celt_assert(_d>0);
+ celt_assert(_d<=54);
+ shift=EC_ILOG(_d^(_d-1));
+ inv=INV_TABLE[(_d-1)>>shift];
+ shift--;
+ one=1<<shift;
+ mask=one-1;
+ return (_a*(_b>>shift)-(_c>>shift)+
+ ((_a*(_b&mask)+one-(_c&mask))>>shift)-1)*inv&MASK32;
+}
+
+#endif /* SMALL_FOOTPRINT */
+
+/*Although derived separately, the pulse vector coding scheme is equivalent to
+ a Pyramid Vector Quantizer \cite{Fis86}.
+ Some additional notes about an early version appear at
+ http://people.xiph.org/~tterribe/notes/cwrs.html, but the codebook ordering
+ and the definitions of some terms have evolved since that was written.
+
+ The conversion from a pulse vector to an integer index (encoding) and back
+ (decoding) is governed by two related functions, V(N,K) and U(N,K).
+
+ V(N,K) = the number of combinations, with replacement, of N items, taken K
+ at a time, when a sign bit is added to each item taken at least once (i.e.,
+ the number of N-dimensional unit pulse vectors with K pulses).
+ One way to compute this is via
+ V(N,K) = K>0 ? sum(k=1...K,2**k*choose(N,k)*choose(K-1,k-1)) : 1,
+ where choose() is the binomial function.
+ A table of values for N<10 and K<10 looks like:
+ V[10][10] = {
+ {1, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {1, 2, 2, 2, 2, 2, 2, 2, 2, 2},
+ {1, 4, 8, 12, 16, 20, 24, 28, 32, 36},
+ {1, 6, 18, 38, 66, 102, 146, 198, 258, 326},
+ {1, 8, 32, 88, 192, 360, 608, 952, 1408, 1992},
+ {1, 10, 50, 170, 450, 1002, 1970, 3530, 5890, 9290},
+ {1, 12, 72, 292, 912, 2364, 5336, 10836, 20256, 35436},
+ {1, 14, 98, 462, 1666, 4942, 12642, 28814, 59906, 115598},
+ {1, 16, 128, 688, 2816, 9424, 27008, 68464, 157184, 332688},
+ {1, 18, 162, 978, 4482, 16722, 53154, 148626, 374274, 864146}
+ };
+
+ U(N,K) = the number of such combinations wherein N-1 objects are taken at
+ most K-1 at a time.
+ This is given by
+ U(N,K) = sum(k=0...K-1,V(N-1,k))
+ = K>0 ? (V(N-1,K-1) + V(N,K-1))/2 : 0.
+ The latter expression also makes clear that U(N,K) is half the number of such
+ combinations wherein the first object is taken at least once.
+ Although it may not be clear from either of these definitions, U(N,K) is the
+ natural function to work with when enumerating the pulse vector codebooks,
+ not V(N,K).
+ U(N,K) is not well-defined for N=0, but with the extension
+ U(0,K) = K>0 ? 0 : 1,
+ the function becomes symmetric: U(N,K) = U(K,N), with a similar table:
+ U[10][10] = {
+ {1, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+ {0, 1, 1, 1, 1, 1, 1, 1, 1, 1},
+ {0, 1, 3, 5, 7, 9, 11, 13, 15, 17},
+ {0, 1, 5, 13, 25, 41, 61, 85, 113, 145},
+ {0, 1, 7, 25, 63, 129, 231, 377, 575, 833},
+ {0, 1, 9, 41, 129, 321, 681, 1289, 2241, 3649},
+ {0, 1, 11, 61, 231, 681, 1683, 3653, 7183, 13073},
+ {0, 1, 13, 85, 377, 1289, 3653, 8989, 19825, 40081},
+ {0, 1, 15, 113, 575, 2241, 7183, 19825, 48639, 108545},
+ {0, 1, 17, 145, 833, 3649, 13073, 40081, 108545, 265729}
+ };
+
+ With this extension, V(N,K) may be written in terms of U(N,K):
+ V(N,K) = U(N,K) + U(N,K+1)
+ for all N>=0, K>=0.
+ Thus U(N,K+1) represents the number of combinations where the first element
+ is positive or zero, and U(N,K) represents the number of combinations where
+ it is negative.
+ With a large enough table of U(N,K) values, we could write O(N) encoding
+ and O(min(N*log(K),N+K)) decoding routines, but such a table would be
+ prohibitively large for small embedded devices (K may be as large as 32767
+ for small N, and N may be as large as 200).
+
+ Both functions obey the same recurrence relation:
+ V(N,K) = V(N-1,K) + V(N,K-1) + V(N-1,K-1),
+ U(N,K) = U(N-1,K) + U(N,K-1) + U(N-1,K-1),
+ for all N>0, K>0, with different initial conditions at N=0 or K=0.
+ This allows us to construct a row of one of the tables above given the
+ previous row or the next row.
+ Thus we can derive O(NK) encoding and decoding routines with O(K) memory
+ using only addition and subtraction.
+
+ When encoding, we build up from the U(2,K) row and work our way forwards.
+ When decoding, we need to start at the U(N,K) row and work our way backwards,
+ which requires a means of computing U(N,K).
+ U(N,K) may be computed from two previous values with the same N:
+ U(N,K) = ((2*N-1)*U(N,K-1) - U(N,K-2))/(K-1) + U(N,K-2)
+ for all N>1, and since U(N,K) is symmetric, a similar relation holds for two
+ previous values with the same K:
+ U(N,K>1) = ((2*K-1)*U(N-1,K) - U(N-2,K))/(N-1) + U(N-2,K)
+ for all K>1.
+ This allows us to construct an arbitrary row of the U(N,K) table by starting
+ with the first two values, which are constants.
+ This saves roughly 2/3 the work in our O(NK) decoding routine, but costs O(K)
+ multiplications.
+ Similar relations can be derived for V(N,K), but are not used here.
+
+ For N>0 and K>0, U(N,K) and V(N,K) take on the form of an (N-1)-degree
+ polynomial for fixed N.
+ The first few are
+ U(1,K) = 1,
+ U(2,K) = 2*K-1,
+ U(3,K) = (2*K-2)*K+1,
+ U(4,K) = (((4*K-6)*K+8)*K-3)/3,
+ U(5,K) = ((((2*K-4)*K+10)*K-8)*K+3)/3,
+ and
+ V(1,K) = 2,
+ V(2,K) = 4*K,
+ V(3,K) = 4*K*K+2,
+ V(4,K) = 8*(K*K+2)*K/3,
+ V(5,K) = ((4*K*K+20)*K*K+6)/3,
+ for all K>0.
+ This allows us to derive O(N) encoding and O(N*log(K)) decoding routines for
+ small N (and indeed decoding is also O(N) for N<3).
+
+ @ARTICLE{Fis86,
+ author="Thomas R. Fischer",
+ title="A Pyramid Vector Quantizer",
+ journal="IEEE Transactions on Information Theory",
+ volume="IT-32",
+ number=4,
+ pages="568--583",
+ month=Jul,
+ year=1986
+ }*/
+
+#ifndef SMALL_FOOTPRINT
+/*Compute U(2,_k).
+ Note that this may be called with _k=32768 (maxK[2]+1).*/
+static inline unsigned ucwrs2(unsigned _k){
+ celt_assert(_k>0);
+ return _k+(_k-1);
+}
+
+/*Compute V(2,_k).*/
+static inline opus_uint32 ncwrs2(int _k){
+ celt_assert(_k>0);
+ return 4*(opus_uint32)_k;
+}
+
+/*Compute U(3,_k).
+ Note that this may be called with _k=32768 (maxK[3]+1).*/
+static inline opus_uint32 ucwrs3(unsigned _k){
+ celt_assert(_k>0);
+ return (2*(opus_uint32)_k-2)*_k+1;
+}
+
+/*Compute V(3,_k).*/
+static inline opus_uint32 ncwrs3(int _k){
+ celt_assert(_k>0);
+ return 2*(2*(unsigned)_k*(opus_uint32)_k+1);
+}
+
+/*Compute U(4,_k).*/
+static inline opus_uint32 ucwrs4(int _k){
+ celt_assert(_k>0);
+ return imusdiv32odd(2*_k,(2*_k-3)*(opus_uint32)_k+4,3,1);
+}
+
+/*Compute V(4,_k).*/
+static inline opus_uint32 ncwrs4(int _k){
+ celt_assert(_k>0);
+ return ((_k*(opus_uint32)_k+2)*_k)/3<<3;
+}
+
+#endif /* SMALL_FOOTPRINT */
+
+/*Computes the next row/column of any recurrence that obeys the relation
+ u[i][j]=u[i-1][j]+u[i][j-1]+u[i-1][j-1].
+ _ui0 is the base case for the new row/column.*/
+static inline void unext(opus_uint32 *_ui,unsigned _len,opus_uint32 _ui0){
+ opus_uint32 ui1;
+ unsigned j;
+ /*This do-while will overrun the array if we don't have storage for at least
+ 2 values.*/
+ j=1; do {
+ ui1=UADD32(UADD32(_ui[j],_ui[j-1]),_ui0);
+ _ui[j-1]=_ui0;
+ _ui0=ui1;
+ } while (++j<_len);
+ _ui[j-1]=_ui0;
+}
+
+/*Computes the previous row/column of any recurrence that obeys the relation
+ u[i-1][j]=u[i][j]-u[i][j-1]-u[i-1][j-1].
+ _ui0 is the base case for the new row/column.*/
+static inline void uprev(opus_uint32 *_ui,unsigned _n,opus_uint32 _ui0){
+ opus_uint32 ui1;
+ unsigned j;
+ /*This do-while will overrun the array if we don't have storage for at least
+ 2 values.*/
+ j=1; do {
+ ui1=USUB32(USUB32(_ui[j],_ui[j-1]),_ui0);
+ _ui[j-1]=_ui0;
+ _ui0=ui1;
+ } while (++j<_n);
+ _ui[j-1]=_ui0;
+}
+
+/*Compute V(_n,_k), as well as U(_n,0..._k+1).
+ _u: On exit, _u[i] contains U(_n,i) for i in [0..._k+1].*/
+static opus_uint32 ncwrs_urow(unsigned _n,unsigned _k,opus_uint32 *_u){
+ opus_uint32 um2;
+ unsigned len;
+ unsigned k;
+ len=_k+2;
+ /*We require storage at least 3 values (e.g., _k>0).*/
+ celt_assert(len>=3);
+ _u[0]=0;
+ _u[1]=um2=1;
+#ifndef SMALL_FOOTPRINT
+ /*_k>52 doesn't work in the false branch due to the limits of INV_TABLE,
+ but _k isn't tested here because k<=52 for n=7*/
+ if(_n<=6)
+#endif
+ {
+ /*If _n==0, _u[0] should be 1 and the rest should be 0.*/
+ /*If _n==1, _u[i] should be 1 for i>1.*/
+ celt_assert(_n>=2);
+ /*If _k==0, the following do-while loop will overflow the buffer.*/
+ celt_assert(_k>0);
+ k=2;
+ do _u[k]=(k<<1)-1;
+ while(++k<len);
+ for(k=2;k<_n;k++)unext(_u+1,_k+1,1);
+ }
+#ifndef SMALL_FOOTPRINT
+ else{
+ opus_uint32 um1;
+ opus_uint32 n2m1;
+ _u[2]=n2m1=um1=(_n<<1)-1;
+ for(k=3;k<len;k++){
+ /*U(N,K) = ((2*N-1)*U(N,K-1)-U(N,K-2))/(K-1) + U(N,K-2)*/
+ _u[k]=um2=imusdiv32even(n2m1,um1,um2,k-1)+um2;
+ if(++k>=len)break;
+ _u[k]=um1=imusdiv32odd(n2m1,um2,um1,(k-1)>>1)+um1;
+ }
+ }
+#endif /* SMALL_FOOTPRINT */
+ return _u[_k]+_u[_k+1];
+}
+
+#ifndef SMALL_FOOTPRINT
+
+/*Returns the _i'th combination of _k elements (at most 32767) chosen from a
+ set of size 1 with associated sign bits.
+ _y: Returns the vector of pulses.*/
+static inline void cwrsi1(int _k,opus_uint32 _i,int *_y){
+ int s;
+ s=-(int)_i;
+ _y[0]=(_k+s)^s;
+}
+
+/*Returns the _i'th combination of _k elements (at most 32767) chosen from a
+ set of size 2 with associated sign bits.
+ _y: Returns the vector of pulses.*/
+static inline void cwrsi2(int _k,opus_uint32 _i,int *_y){
+ opus_uint32 p;
+ int s;
+ int yj;
+ p=ucwrs2(_k+1U);
+ s=-(_i>=p);
+ _i-=p&s;
+ yj=_k;
+ _k=(_i+1)>>1;
+ p=_k?ucwrs2(_k):0;
+ _i-=p;
+ yj-=_k;
+ _y[0]=(yj+s)^s;
+ cwrsi1(_k,_i,_y+1);
+}
+
+/*Returns the _i'th combination of _k elements (at most 32767) chosen from a
+ set of size 3 with associated sign bits.
+ _y: Returns the vector of pulses.*/
+static void cwrsi3(int _k,opus_uint32 _i,int *_y){
+ opus_uint32 p;
+ int s;
+ int yj;
+ p=ucwrs3(_k+1U);
+ s=-(_i>=p);
+ _i-=p&s;
+ yj=_k;
+ /*Finds the maximum _k such that ucwrs3(_k)<=_i (tested for all
+ _i<2147418113=U(3,32768)).*/
+ _k=_i>0?(isqrt32(2*_i-1)+1)>>1:0;
+ p=_k?ucwrs3(_k):0;
+ _i-=p;
+ yj-=_k;
+ _y[0]=(yj+s)^s;
+ cwrsi2(_k,_i,_y+1);
+}
+
+/*Returns the _i'th combination of _k elements (at most 1172) chosen from a set
+ of size 4 with associated sign bits.
+ _y: Returns the vector of pulses.*/
+static void cwrsi4(int _k,opus_uint32 _i,int *_y){
+ opus_uint32 p;
+ int s;
+ int yj;
+ int kl;
+ int kr;
+ p=ucwrs4(_k+1);
+ s=-(_i>=p);
+ _i-=p&s;
+ yj=_k;
+ /*We could solve a cubic for k here, but the form of the direct solution does
+ not lend itself well to exact integer arithmetic.
+ Instead we do a binary search on U(4,K).*/
+ kl=0;
+ kr=_k;
+ for(;;){
+ _k=(kl+kr)>>1;
+ p=_k?ucwrs4(_k):0;
+ if(p<_i){
+ if(_k>=kr)break;
+ kl=_k+1;
+ }
+ else if(p>_i)kr=_k-1;
+ else break;
+ }
+ _i-=p;
+ yj-=_k;
+ _y[0]=(yj+s)^s;
+ cwrsi3(_k,_i,_y+1);
+}
+
+#endif /* SMALL_FOOTPRINT */
+
+/*Returns the _i'th combination of _k elements chosen from a set of size _n
+ with associated sign bits.
+ _y: Returns the vector of pulses.
+ _u: Must contain entries [0..._k+1] of row _n of U() on input.
+ Its contents will be destructively modified.*/
+static void cwrsi(int _n,int _k,opus_uint32 _i,int *_y,opus_uint32 *_u){
+ int j;
+ celt_assert(_n>0);
+ j=0;
+ do{
+ opus_uint32 p;
+ int s;
+ int yj;
+ p=_u[_k+1];
+ s=-(_i>=p);
+ _i-=p&s;
+ yj=_k;
+ p=_u[_k];
+ while(p>_i)p=_u[--_k];
+ _i-=p;
+ yj-=_k;
+ _y[j]=(yj+s)^s;
+ uprev(_u,_k+2,0);
+ }
+ while(++j<_n);
+}
+
+/*Returns the index of the given combination of K elements chosen from a set
+ of size 1 with associated sign bits.
+ _y: The vector of pulses, whose sum of absolute values is K.
+ _k: Returns K.*/
+static inline opus_uint32 icwrs1(const int *_y,int *_k){
+ *_k=abs(_y[0]);
+ return _y[0]<0;
+}
+
+#ifndef SMALL_FOOTPRINT
+
+/*Returns the index of the given combination of K elements chosen from a set
+ of size 2 with associated sign bits.
+ _y: The vector of pulses, whose sum of absolute values is K.
+ _k: Returns K.*/
+static inline opus_uint32 icwrs2(const int *_y,int *_k){
+ opus_uint32 i;
+ int k;
+ i=icwrs1(_y+1,&k);
+ i+=k?ucwrs2(k):0;
+ k+=abs(_y[0]);
+ if(_y[0]<0)i+=ucwrs2(k+1U);
+ *_k=k;
+ return i;
+}
+
+/*Returns the index of the given combination of K elements chosen from a set
+ of size 3 with associated sign bits.
+ _y: The vector of pulses, whose sum of absolute values is K.
+ _k: Returns K.*/
+static inline opus_uint32 icwrs3(const int *_y,int *_k){
+ opus_uint32 i;
+ int k;
+ i=icwrs2(_y+1,&k);
+ i+=k?ucwrs3(k):0;
+ k+=abs(_y[0]);
+ if(_y[0]<0)i+=ucwrs3(k+1U);
+ *_k=k;
+ return i;
+}
+
+/*Returns the index of the given combination of K elements chosen from a set
+ of size 4 with associated sign bits.
+ _y: The vector of pulses, whose sum of absolute values is K.
+ _k: Returns K.*/
+static inline opus_uint32 icwrs4(const int *_y,int *_k){
+ opus_uint32 i;
+ int k;
+ i=icwrs3(_y+1,&k);
+ i+=k?ucwrs4(k):0;
+ k+=abs(_y[0]);
+ if(_y[0]<0)i+=ucwrs4(k+1);
+ *_k=k;
+ return i;
+}
+
+#endif /* SMALL_FOOTPRINT */
+
+/*Returns the index of the given combination of K elements chosen from a set
+ of size _n with associated sign bits.
+ _y: The vector of pulses, whose sum of absolute values must be _k.
+ _nc: Returns V(_n,_k).*/
+static inline opus_uint32 icwrs(int _n,int _k,opus_uint32 *_nc,const int *_y,
+ opus_uint32 *_u){
+ opus_uint32 i;
+ int j;
+ int k;
+ /*We can't unroll the first two iterations of the loop unless _n>=2.*/
+ celt_assert(_n>=2);
+ _u[0]=0;
+ for(k=1;k<=_k+1;k++)_u[k]=(k<<1)-1;
+ i=icwrs1(_y+_n-1,&k);
+ j=_n-2;
+ i+=_u[k];
+ k+=abs(_y[j]);
+ if(_y[j]<0)i+=_u[k+1];
+ while(j-->0){
+ unext(_u,_k+2,0);
+ i+=_u[k];
+ k+=abs(_y[j]);
+ if(_y[j]<0)i+=_u[k+1];
+ }
+ *_nc=_u[k]+_u[k+1];
+ return i;
+}
+
+#ifdef CUSTOM_MODES
+void get_required_bits(opus_int16 *_bits,int _n,int _maxk,int _frac){
+ int k;
+ /*_maxk==0 => there's nothing to do.*/
+ celt_assert(_maxk>0);
+ _bits[0]=0;
+ if (_n==1)
+ {
+ for (k=1;k<=_maxk;k++)
+ _bits[k] = 1<<_frac;
+ }
+ else {
+ VARDECL(opus_uint32,u);
+ SAVE_STACK;
+ ALLOC(u,_maxk+2U,opus_uint32);
+ ncwrs_urow(_n,_maxk,u);
+ for(k=1;k<=_maxk;k++)
+ _bits[k]=log2_frac(u[k]+u[k+1],_frac);
+ RESTORE_STACK;
+ }
+}
+#endif /* CUSTOM_MODES */
+
+void encode_pulses(const int *_y,int _n,int _k,ec_enc *_enc){
+ opus_uint32 i;
+ celt_assert(_k>0);
+#ifndef SMALL_FOOTPRINT
+ switch(_n){
+ case 2:{
+ i=icwrs2(_y,&_k);
+ ec_enc_uint(_enc,i,ncwrs2(_k));
+ }break;
+ case 3:{
+ i=icwrs3(_y,&_k);
+ ec_enc_uint(_enc,i,ncwrs3(_k));
+ }break;
+ case 4:{
+ i=icwrs4(_y,&_k);
+ ec_enc_uint(_enc,i,ncwrs4(_k));
+ }break;
+ default:
+ {
+#endif
+ VARDECL(opus_uint32,u);
+ opus_uint32 nc;
+ SAVE_STACK;
+ ALLOC(u,_k+2U,opus_uint32);
+ i=icwrs(_n,_k,&nc,_y,u);
+ ec_enc_uint(_enc,i,nc);
+ RESTORE_STACK;
+#ifndef SMALL_FOOTPRINT
+ }
+ break;
+ }
+#endif
+}
+
+void decode_pulses(int *_y,int _n,int _k,ec_dec *_dec)
+{
+ celt_assert(_k>0);
+#ifndef SMALL_FOOTPRINT
+ switch(_n){
+ case 2:cwrsi2(_k,ec_dec_uint(_dec,ncwrs2(_k)),_y);break;
+ case 3:cwrsi3(_k,ec_dec_uint(_dec,ncwrs3(_k)),_y);break;
+ case 4:cwrsi4(_k,ec_dec_uint(_dec,ncwrs4(_k)),_y);break;
+ default:
+ {
+#endif
+ VARDECL(opus_uint32,u);
+ SAVE_STACK;
+ ALLOC(u,_k+2U,opus_uint32);
+ cwrsi(_n,_k,ec_dec_uint(_dec,ncwrs_urow(_n,_k,u)),_y,u);
+ RESTORE_STACK;
+#ifndef SMALL_FOOTPRINT
+ }
+ break;
+ }
+#endif
+}