Diffstat (limited to 'core/multimedia/opieplayer/vorbis/tremor/bitwise.c') (more/less context) (ignore whitespace changes)
| -rw-r--r-- | core/multimedia/opieplayer/vorbis/tremor/bitwise.c | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/core/multimedia/opieplayer/vorbis/tremor/bitwise.c b/core/multimedia/opieplayer/vorbis/tremor/bitwise.c new file mode 100644 index 0000000..ccb82b0 --- a/dev/null +++ b/core/multimedia/opieplayer/vorbis/tremor/bitwise.c @@ -0,0 +1,265 @@ +/******************************************************************** + * * + * 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 <string.h> +#include <stdlib.h> +#include "ogg.h" + +static unsigned long mask[]= +{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 }; + +/* mark read process as having run off the end */ +static void _adv_halt(oggpack_buffer *b){ + b->headptr=b->head->buffer->data+b->head->begin+b->head->length; + b->headend=-1; + b->headbit=0; +} + +/* spans forward, skipping as many bytes as headend is negative; if + headend is zero, simply finds next byte. If we're up to the end + of the buffer, leaves headend at zero. If we've read past the end, + halt the decode process. */ +static void _span(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->headend+=b->head->length; + }else{ + /* we've either met the end of decode, or gone past it. halt + only if we're past */ + if(b->headend<0 || b->headbit) + /* read has fallen off the end */ + _adv_halt(b); + + break; + } + } +} + +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(oggpack_buffer *b,int bits){ + unsigned long m=mask[bits]; + unsigned long ret; + + 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; +} + +/* limited to 32 at a time */ +void oggpack_adv(oggpack_buffer *b,int bits){ + bits+=b->headbit; + b->headbit=bits&7; + b->headptr+=bits/8; + if((b->headend-=bits/8)<1)_span(b); +} + +/* 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; +} + +int oggpack_eop(oggpack_buffer *b){ + if(b->headend<0)return -1; + return 0; +} + +/* bits <= 32 */ +long oggpack_read(oggpack_buffer *b,int bits){ + unsigned long m=mask[bits]; + ogg_uint32_t ret; + + 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+=bits/8; + b->headend-=bits/8; + } + + ret&=m; + b->headbit=bits&7; + return ret; +} + +long oggpack_bytes(oggpack_buffer *b){ + return(b->count+b->headptr-b->head->buffer->data-b->head->begin+ + (b->headbit+7)/8); +} + +long oggpack_bits(oggpack_buffer *b){ + return((b->count+b->headptr-b->head->buffer->data-b->head->begin)*8+ + b->headbit); +} + |