Nyaaori/rockbox
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
rockbox/apps/codecs/libffmpegFLAC/bitstream.h
Tomasz Malesinski 5c54ba49d5 Added macros controlling what goes to IRAM on different targets. 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@11483 a1c6a512-1295-4272-9138-f99709370657
2006-11-09 21:59:27 +00:00

341 lines
8.3 KiB
C
Raw Blame History

/**
* @file bitstream.h
* bitstream api header.
*/
#ifndef BITSTREAM_H
#define BITSTREAM_H
#include <inttypes.h>
#ifndef BUILD_STANDALONE
#include <config.h>
#include <system.h>
#else
#include <stdio.h>
#define IBSS_ATTR
#define ICONST_ATTR
#define ICODE_ATTR
#endif
#ifndef ICODE_ATTR_FLAC
#define ICODE_ATTR_FLAC ICODE_ATTR
#endif
#ifndef IBSS_ATTR_FLAC_DECODED0
#define IBSS_ATTR_FLAC_DECODED0 IBSS_ATTR
#endif
/* Endian conversion routines for standalone compilation */
#ifdef BUILD_STANDALONE
#ifdef BUILD_BIGENDIAN
#define betoh32(x) (x)
#define letoh32(x) swap32(x)
#else
#define letoh32(x) (x)
#define betoh32(x) swap32(x)
#endif
/* Taken from rockbox/firmware/export/system.h */
static inline unsigned short swap16(unsigned short value)
/*
result[15..8] = value[ 7..0];
result[ 7..0] = value[15..8];
*/
{
return (value >> 8) | (value << 8);
}
static inline unsigned long swap32(unsigned long value)
/*
result[31..24] = value[ 7.. 0];
result[23..16] = value[15.. 8];
result[15.. 8] = value[23..16];
result[ 7.. 0] = value[31..24];
*/
{
unsigned long hi = swap16(value >> 16);
unsigned long lo = swap16(value & 0xffff);
return (lo << 16) | hi;
}
#endif
/* FLAC files are big-endian */
#define ALT_BITSTREAM_READER_BE
#define NEG_SSR32(a,s) (((int32_t)(a))>>(32-(s)))
#define NEG_USR32(a,s) (((uint32_t)(a))>>(32-(s)))
/* bit input */
/* buffer, buffer_end and size_in_bits must be present and used by every reader */
typedef struct GetBitContext {
const uint8_t *buffer, *buffer_end;
int index;
int size_in_bits;
} GetBitContext;
#define VLC_TYPE int16_t
typedef struct VLC {
int bits;
VLC_TYPE (*table)[2]; ///< code, bits
int table_size, table_allocated;
} VLC;
typedef struct RL_VLC_ELEM {
int16_t level;
int8_t len;
uint8_t run;
} RL_VLC_ELEM;
#if defined(ARCH_SPARC) || defined(ARCH_ARMV4L)
#define UNALIGNED_STORES_ARE_BAD
#endif
/* used to avoid missaligned exceptions on some archs (alpha, ...) */
#if defined(ARCH_X86) || defined(ARCH_X86_64)
# define unaligned32(a) (*(const uint32_t*)(a))
#else
# ifdef __GNUC__
static inline uint32_t unaligned32(const void *v) {
struct Unaligned {
uint32_t i;
} __attribute__((packed));
return ((const struct Unaligned *) v)->i;
}
# elif defined(__DECC)
static inline uint32_t unaligned32(const void *v) {
return *(const __unaligned uint32_t *) v;
}
# else
static inline uint32_t unaligned32(const void *v) {
return *(const uint32_t *) v;
}
# endif
#endif //!ARCH_X86
/* Bitstream reader API docs:
name
abritary name which is used as prefix for the internal variables
gb
getbitcontext
OPEN_READER(name, gb)
loads gb into local variables
CLOSE_READER(name, gb)
stores local vars in gb
UPDATE_CACHE(name, gb)
refills the internal cache from the bitstream
after this call at least MIN_CACHE_BITS will be available,
GET_CACHE(name, gb)
will output the contents of the internal cache, next bit is MSB of 32 or 64 bit (FIXME 64bit)
SHOW_UBITS(name, gb, num)
will return the next num bits
SHOW_SBITS(name, gb, num)
will return the next num bits and do sign extension
SKIP_BITS(name, gb, num)
will skip over the next num bits
note, this is equivalent to SKIP_CACHE; SKIP_COUNTER
SKIP_CACHE(name, gb, num)
will remove the next num bits from the cache (note SKIP_COUNTER MUST be called before UPDATE_CACHE / CLOSE_READER)
SKIP_COUNTER(name, gb, num)
will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS)
LAST_SKIP_CACHE(name, gb, num)
will remove the next num bits from the cache if it is needed for UPDATE_CACHE otherwise it will do nothing
LAST_SKIP_BITS(name, gb, num)
is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER
for examples see get_bits, show_bits, skip_bits, get_vlc
*/
static inline int unaligned32_be(const void *v)
{
#ifdef CONFIG_ALIGN
const uint8_t *p=v;
return (((p[0]<<8) | p[1])<<16) | (p[2]<<8) | (p[3]);
#else
return betoh32( unaligned32(v)); //original
#endif
}
static inline int unaligned32_le(const void *v)
{
#ifdef CONFIG_ALIGN
const uint8_t *p=v;
return (((p[3]<<8) | p[2])<<16) | (p[1]<<8) | (p[0]);
#else
return letoh32( unaligned32(v)); //original
#endif
}
# define MIN_CACHE_BITS 25
# define OPEN_READER(name, gb)\
int name##_index= (gb)->index;\
int name##_cache= 0;\
# define CLOSE_READER(name, gb)\
(gb)->index= name##_index;\
# ifdef ALT_BITSTREAM_READER_LE
# define UPDATE_CACHE(name, gb)\
name##_cache= unaligned32_le( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\
# define SKIP_CACHE(name, gb, num)\
name##_cache >>= (num);
# else
# define UPDATE_CACHE(name, gb)\
name##_cache= unaligned32_be( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\
# define SKIP_CACHE(name, gb, num)\
name##_cache <<= (num);
# endif
// FIXME name?
# define SKIP_COUNTER(name, gb, num)\
name##_index += (num);\
# define SKIP_BITS(name, gb, num)\
{\
SKIP_CACHE(name, gb, num)\
SKIP_COUNTER(name, gb, num)\
}\
# define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
# define LAST_SKIP_CACHE(name, gb, num) ;
# ifdef ALT_BITSTREAM_READER_LE
# define SHOW_UBITS(name, gb, num)\
((name##_cache) & (NEG_USR32(0xffffffff,num)))
# else
# define SHOW_UBITS(name, gb, num)\
NEG_USR32(name##_cache, num)
# endif
# define SHOW_SBITS(name, gb, num)\
NEG_SSR32(name##_cache, num)
# define GET_CACHE(name, gb)\
((uint32_t)name##_cache)
static inline int get_bits_count(GetBitContext *s){
return s->index;
}
static inline int get_sbits(GetBitContext *s, int n){
register int tmp;
OPEN_READER(re, s)
UPDATE_CACHE(re, s)
tmp= SHOW_SBITS(re, s, n);
LAST_SKIP_BITS(re, s, n)
CLOSE_READER(re, s)
return tmp;
}
/**
* reads 0-17 bits.
* Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
*/
static inline unsigned int get_bits(GetBitContext *s, int n){
register int tmp;
OPEN_READER(re, s)
UPDATE_CACHE(re, s)
tmp= SHOW_UBITS(re, s, n);
LAST_SKIP_BITS(re, s, n)
CLOSE_READER(re, s)
return tmp;
}
unsigned int get_bits_long(GetBitContext *s, int n) ICODE_ATTR_FLAC;
/**
* shows 0-17 bits.
* Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
*/
static inline unsigned int show_bits(GetBitContext *s, int n){
register int tmp;
OPEN_READER(re, s)
UPDATE_CACHE(re, s)
tmp= SHOW_UBITS(re, s, n);
// CLOSE_READER(re, s)
return tmp;
}
unsigned int show_bits_long(GetBitContext *s, int n) ICODE_ATTR_FLAC;
static inline void skip_bits(GetBitContext *s, int n){
//Note gcc seems to optimize this to s->index+=n for the ALT_READER :))
OPEN_READER(re, s)
UPDATE_CACHE(re, s)
LAST_SKIP_BITS(re, s, n)
CLOSE_READER(re, s)
}
static inline unsigned int get_bits1(GetBitContext *s){
int index= s->index;
uint8_t result= s->buffer[ index>>3 ];
#ifdef ALT_BITSTREAM_READER_LE
result>>= (index&0x07);
result&= 1;
#else
result<<= (index&0x07);
result>>= 8 - 1;
#endif
index++;
s->index= index;
return result;
}
static inline unsigned int show_bits1(GetBitContext *s){
return show_bits(s, 1);
}
static inline void skip_bits1(GetBitContext *s){
skip_bits(s, 1);
}
/**
* init GetBitContext.
* @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits
* because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
* @param bit_size the size of the buffer in bits
*/
static inline void init_get_bits(GetBitContext *s,
const uint8_t *buffer, int bit_size)
{
int buffer_size= (bit_size+7)>>3;
if(buffer_size < 0 || bit_size < 0) {
buffer_size = bit_size = 0;
buffer = 0;
}
s->buffer= buffer;
s->size_in_bits= bit_size;
s->buffer_end= buffer + buffer_size;
s->index=0;
{
OPEN_READER(re, s)
UPDATE_CACHE(re, s)
UPDATE_CACHE(re, s)
CLOSE_READER(re, s)
}
}
void align_get_bits(GetBitContext *s) ICODE_ATTR_FLAC;
#endif /* BITSTREAM_H */
Reference in a new issue View git blame Copy permalink