ref: dfb3e6866e1a13aa82accdf1d9961967ac900546
dir: /libcelt/entdec.c/
/* Copyright (c) 2001-2008 Timothy B. Terriberry Copyright (c) 2008-2009 Xiph.Org Foundation */ /* 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. - Neither the name of the Xiph.org Foundation nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. 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 FOUNDATION 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 <stddef.h> #include "entdec.h" #include "os_support.h" #include "arch.h" void ec_byte_readinit(ec_byte_buffer *_b,unsigned char *_buf,ec_uint32 _bytes){ _b->buf=_b->ptr=_buf; _b->storage=_bytes; _b->end_ptr=_b->buf+_bytes-1; } unsigned char ec_byte_look_at_end(ec_byte_buffer *_b){ celt_assert2 (_b->end_ptr >= _b->buf, "Trying to read raw bits before the beginning of the stream"); return *(_b->end_ptr--); } void ec_byte_adv1(ec_byte_buffer *_b){ _b->ptr++; } int ec_byte_read1(ec_byte_buffer *_b){ ptrdiff_t endbyte; endbyte=_b->ptr-_b->buf; if(endbyte>=_b->storage)return -1; else return *(_b->ptr++); } ec_uint32 ec_dec_uint(ec_dec *_this,ec_uint32 _ft){ ec_uint32 t; unsigned ft; unsigned s; int ftb; t=0; /*In order to optimize EC_ILOG(), it is undefined for the value 0.*/ celt_assert(_ft>1); _ft--; ftb=EC_ILOG(_ft); if(ftb>EC_UNIT_BITS){ ftb-=EC_UNIT_BITS; ft=(unsigned)(_ft>>ftb)+1; s=ec_decode(_this,ft); ec_dec_update(_this,s,s+1,ft); t=t<<EC_UNIT_BITS|s; t = t<<ftb|ec_dec_bits(_this,ftb&(1<<ftb)-1); if (t>_ft) { _this->error |= 1; t = _ft; } return t; } else { _ft++; s=ec_decode(_this,(unsigned)_ft); ec_dec_update(_this,s,s+1,(unsigned)_ft); t=t<<ftb|s; return t; } } int ec_dec_get_error(ec_dec *_this) { return _this->error || (ec_dec_tell(_this,0) > 8*_this->buf->storage); }