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| author | Björn Stenberg <bjorn@haxx.se> | 2008-11-05 13:30:58 +0000 |
|---|---|---|
| committer | Björn Stenberg <bjorn@haxx.se> | 2008-11-05 13:30:58 +0000 |
| commit | 45bd7e024603ba47207e5cc64c61e4116e8f1261 (patch) | |
| tree | cf789bb0ce99eb8b153c5445c535ef5c4e4ead62 /apps/codecs/libtremor/bitwise.c | |
| parent | 7ec9ceeaaabb75adaa790b41eba6dec020232fa6 (diff) | |
| download | rockbox-45bd7e024603ba47207e5cc64c61e4116e8f1261.zip rockbox-45bd7e024603ba47207e5cc64c61e4116e8f1261.tar.gz rockbox-45bd7e024603ba47207e5cc64c61e4116e8f1261.tar.bz2 rockbox-45bd7e024603ba47207e5cc64c61e4116e8f1261.tar.xz | |
Codec lib directories renamed, except for demac.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@19018 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'apps/codecs/libtremor/bitwise.c')
| -rw-r--r-- | apps/codecs/libtremor/bitwise.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/apps/codecs/libtremor/bitwise.c b/apps/codecs/libtremor/bitwise.c new file mode 100644 index 0000000..caa42f4 --- /dev/null +++ b/apps/codecs/libtremor/bitwise.c @@ -0,0 +1,214 @@ +/******************************************************************** + * * + * THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE. * + * * + * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS * + * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * + * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * + * * + * THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002 * + * BY THE Xiph.Org FOUNDATION http://www.xiph.org/ * + * * + ******************************************************************** + + function: packing variable sized words into an octet stream + + ********************************************************************/ + +/* We're 'LSb' endian; if we write a word but read individual bits, + then we'll read the lsb first */ + +#include "config-tremor.h" +#include <string.h> +#include "ogg.h" + +const unsigned long oggpack_mask[] ICONST_ATTR = +{0x00000000,0x00000001,0x00000003,0x00000007,0x0000000f, + 0x0000001f,0x0000003f,0x0000007f,0x000000ff,0x000001ff, + 0x000003ff,0x000007ff,0x00000fff,0x00001fff,0x00003fff, + 0x00007fff,0x0000ffff,0x0001ffff,0x0003ffff,0x0007ffff, + 0x000fffff,0x001fffff,0x003fffff,0x007fffff,0x00ffffff, + 0x01ffffff,0x03ffffff,0x07ffffff,0x0fffffff,0x1fffffff, + 0x3fffffff,0x7fffffff,0xffffffff }; + +void oggpack_readinit(oggpack_buffer *b,ogg_reference *r){ + memset(b,0,sizeof(*b)); + + b->tail=b->head=r; + b->count=0; + b->headptr=b->head->buffer->data+b->head->begin; + b->headend=b->head->length; + _span(b); +} + +#define _lookspan() while(!end){\ + head=head->next;\ + if(!head) return -1;\ + ptr=head->buffer->data + head->begin;\ + end=head->length;\ + } + +/* Read in bits without advancing the bitptr; bits <= 32 */ +long oggpack_look_full(oggpack_buffer *b,int bits) ICODE_ATTR_TREMOR_NOT_MDCT; +long oggpack_look_full(oggpack_buffer *b,int bits){ + unsigned long m=oggpack_mask[bits]; + unsigned long ret=-1; + + bits+=b->headbit; + + if(bits >= b->headend<<3){ + int end=b->headend; + unsigned char *ptr=b->headptr; + ogg_reference *head=b->head; + + if(end<0)return -1; + + if(bits){ + _lookspan(); + ret=*ptr++>>b->headbit; + if(bits>8){ + --end; + _lookspan(); + ret|=*ptr++<<(8-b->headbit); + if(bits>16){ + --end; + _lookspan(); + ret|=*ptr++<<(16-b->headbit); + if(bits>24){ + --end; + _lookspan(); + ret|=*ptr++<<(24-b->headbit); + if(bits>32 && b->headbit){ + --end; + _lookspan(); + ret|=*ptr<<(32-b->headbit); + } + } + } + } + } + + }else{ + + /* make this a switch jump-table */ + ret=b->headptr[0]>>b->headbit; + if(bits>8){ + ret|=b->headptr[1]<<(8-b->headbit); + if(bits>16){ + ret|=b->headptr[2]<<(16-b->headbit); + if(bits>24){ + ret|=b->headptr[3]<<(24-b->headbit); + if(bits>32 && b->headbit) + ret|=b->headptr[4]<<(32-b->headbit); + } + } + } + } + + ret&=m; + return ret; +} + +/* spans forward and finds next byte. Never halts */ +static void _span_one(oggpack_buffer *b){ + while(b->headend<1){ + if(b->head->next){ + b->count+=b->head->length; + b->head=b->head->next; + b->headptr=b->head->buffer->data+b->head->begin; + b->headend=b->head->length; + }else + break; + } +} + +static int _halt_one(oggpack_buffer *b){ + if(b->headend<1){ + _adv_halt(b); + return -1; + } + return 0; +} + +/* bits <= 32 */ +long oggpack_read(oggpack_buffer *b,int bits) ICODE_ATTR_TREMOR_NOT_MDCT; +long oggpack_read(oggpack_buffer *b,int bits){ + unsigned long m=oggpack_mask[bits]; + ogg_uint32_t ret=-1; + + bits+=b->headbit; + + if(bits >= b->headend<<3){ + + if(b->headend<0)return -1; + + if(bits){ + if (_halt_one(b)) return -1; + ret=*b->headptr>>b->headbit; + + if(bits>=8){ + ++b->headptr; + --b->headend; + _span_one(b); + if(bits>8){ + if (_halt_one(b)) return -1; + ret|=*b->headptr<<(8-b->headbit); + + if(bits>=16){ + ++b->headptr; + --b->headend; + _span_one(b); + if(bits>16){ + if (_halt_one(b)) return -1; + ret|=*b->headptr<<(16-b->headbit); + + if(bits>=24){ + ++b->headptr; + --b->headend; + _span_one(b); + if(bits>24){ + if (_halt_one(b)) return -1; + ret|=*b->headptr<<(24-b->headbit); + + if(bits>=32){ + ++b->headptr; + --b->headend; + _span_one(b); + if(bits>32){ + if (_halt_one(b)) return -1; + if(b->headbit)ret|=*b->headptr<<(32-b->headbit); + + } + } + } + } + } + } + } + } + } + }else{ + + ret=b->headptr[0]>>b->headbit; + if(bits>8){ + ret|=b->headptr[1]<<(8-b->headbit); + if(bits>16){ + ret|=b->headptr[2]<<(16-b->headbit); + if(bits>24){ + ret|=b->headptr[3]<<(24-b->headbit); + if(bits>32 && b->headbit){ + ret|=b->headptr[4]<<(32-b->headbit); + } + } + } + } + + b->headptr+=((unsigned)bits)/8; + b->headend-=((unsigned)bits)/8; + } + + ret&=m; + b->headbit=bits&7; + return ret; +} + |