Made a second version of ec_{en|de}code optimised for encoding bits (no div

required) and using it in ec_{en|de}c_bits()

libcelt/entdec.c

@@ -88,13 +88,13 @@ ec_uint32 ec_dec_bits(ec_dec *_this,int _ftb){
   unsigned  ft;
   t=0;
   while(_ftb>EC_UNIT_BITS){
-    s=ec_decode(_this,EC_UNIT_MASK+1);
+    s=ec_decode_bin(_this,EC_UNIT_BITS);
     ec_dec_update(_this,s,s+1,EC_UNIT_MASK+1);
     t=t<<EC_UNIT_BITS|s;
     _ftb-=EC_UNIT_BITS;
   }
   ft=1U<<_ftb;
-  s=ec_decode(_this,ft);
+  s=ec_decode_bin(_this,_ftb);
   ec_dec_update(_this,s,s+1,ft);
   t=t<<_ftb|s;
   return t;

libcelt/entdec.h

@@ -42,6 +42,7 @@ void ec_dec_init(ec_dec *_this,ec_byte_buffer *_buf);
            up to and including the one encoded is fh, then the returned value
            will fall in the range [fl,fh).*/
 unsigned ec_decode(ec_dec *_this,unsigned _ft);
+unsigned ec_decode_bin(ec_dec *_this,unsigned bits);
 /*Advance the decoder past the next symbol using the frequency information the
    symbol was encoded with.
   Exactly one call to ec_decode() must have been made so that all necessary

libcelt/entenc.c

@@ -70,11 +70,11 @@ void ec_enc_bits(ec_enc *_this,ec_uint32 _fl,int _ftb){
   while(_ftb>EC_UNIT_BITS){
     _ftb-=EC_UNIT_BITS;
     fl=(unsigned)(_fl>>_ftb)&EC_UNIT_MASK;
-    ec_encode(_this,fl,fl+1,EC_UNIT_MASK+1);
+    ec_encode_bin(_this,fl,fl+1,EC_UNIT_BITS);
   }
   ft=1<<_ftb;
   fl=(unsigned)_fl&ft-1;
-  ec_encode(_this,fl,fl+1,ft);
+  ec_encode_bin(_this,fl,fl+1,_ftb);
 }
 
 void ec_enc_bits64(ec_enc *_this,ec_uint64 _fl,int _ftb){

libcelt/entenc.h

@@ -42,6 +42,7 @@ void ec_enc_init(ec_enc *_this,ec_byte_buffer *_buf);
         decoded value will fall.
   _ft: The sum of the frequencies of all the symbols*/
 void ec_encode(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned _ft);
+void ec_encode_bin(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned bits);
 /*Encodes a sequence of raw bits in the stream.
   _fl:  The bits to encode.
   _ftb: The number of bits to encode.

libcelt/rangedec.c

@@ -168,6 +168,15 @@ unsigned ec_decode(ec_dec *_this,unsigned _ft){
   return _ft-EC_MINI(s+1,_ft);
 }
 
+unsigned ec_decode_bin(ec_dec *_this,unsigned bits){
+   unsigned s;
+   ec_uint32 ft;
+   ft = (ec_uint32)1<<bits;
+   _this->nrm=_this->rng>>bits;
+   s=(unsigned)((_this->dif-1)/_this->nrm);
+   return ft-EC_MINI(s+1,ft);
+}
+
 void ec_dec_update(ec_dec *_this,unsigned _fl,unsigned _fh,unsigned _ft){
   ec_uint32 s;
   s=_this->nrm*(_ft-_fh);

libcelt/rangeenc.c

@@ -92,6 +92,18 @@ void ec_encode(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned _ft){
   ec_enc_normalize(_this);
 }
 
+void ec_encode_bin(ec_enc *_this,unsigned _fl,unsigned _fh,unsigned bits){
+   ec_uint32 r, ft;
+   r=_this->rng>>bits;
+   ft = (ec_uint32)1<<bits;
+   if(_fl>0){
+      _this->low+=_this->rng-r*(ft-_fl);
+      _this->rng=r*(_fh-_fl);
+   }
+   else _this->rng-=r*(ft-_fh);
+   ec_enc_normalize(_this);
+}
+
 long ec_enc_tell(ec_enc *_this,int _b){
   ec_uint32 r;
   int       l;