diff --git a/libcelt/entenc.c b/libcelt/entenc.c index d322dae980e9a13b0a92507ceaefafcb4e444924..94201327532a13ac27730197b56aafcdebb65edf 100644 --- a/libcelt/entenc.c +++ b/libcelt/entenc.c @@ -215,6 +215,31 @@ void ec_enc_bits(ec_enc *_this,ec_uint32 _fl,unsigned _bits){ _this->nbits_total+=_bits; } +int ec_enc_patch_initial_bits(ec_enc *_this,unsigned _val,int _nbits){ + int shift; + unsigned mask; + if(_nbits<0||_nbits>EC_SYM_BITS)return -1; + shift=EC_SYM_BITS-_nbits; + mask=(1<<_nbits)-1<<shift; + if(_this->offs>0){ + /*The first byte has been finalized.*/ + _this->buf[0]=(unsigned char)(_this->buf[0]&~mask|_val<<shift); + } + else if(_this->rem>=0){ + /*The first byte is still awaiting carry propagation.*/ + _this->rem=_this->rem&~mask|_val<<shift; + } + else if(_this->rng<=EC_CODE_TOP>>shift){ + /*The renormalization loop has never been run.*/ + _this->val=_this->val&~((ec_uint32)mask<<EC_CODE_SHIFT)| + (ec_uint32)_val<<EC_CODE_SHIFT+shift; + } + /*The encoder hasn't even encoded _nbits of data yet.*/ + else return -1; + /*Success!*/ + return 0; +} + void ec_enc_shrink(ec_enc *_this,ec_uint32 _size){ celt_assert(_this->offs+_this->end_offs<=_size); CELT_MOVE(_this->buf+_size-_this->end_offs,