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| author | Timothy B. Terriberry <tterribe@xiph.org> | 2011-02-14 22:40:27 +0300 |
|---|---|---|
| committer | Jean-Marc Valin <jean-marc.valin@octasic.com> | 2011-02-14 22:40:27 +0300 |
| commit | b3c05b6be2a6579af55a625903e9e70687a4d77f (patch) | |
| tree | ad55d2c059c311aac664e32c4b24b0efff9e67e5 | |
| parent | 079b91695099adacffc3dd7d5f6c4ae1e7515bdf (diff) | |
Implements ec_enc_patch_initial_bits()
| -rw-r--r-- | libcelt/entenc.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/libcelt/entenc.c b/libcelt/entenc.c index d322dae..9420132 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, |