+/*
+ * Copyright (c) 2016 Alexandra Hájková
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
/**
- * @file bitstream.h
- * bitstream api header.
+ * @file
+ * functions for reading bits from a buffer
*/
-#ifndef BITSTREAM_H
-#define BITSTREAM_H
-
-//#define ALT_BITSTREAM_WRITER
-//#define ALIGNED_BITSTREAM_WRITER
-
-#define ALT_BITSTREAM_READER
-//#define LIBMPEG2_BITSTREAM_READER
-//#define A32_BITSTREAM_READER
-#define LIBMPEG2_BITSTREAM_READER_HACK //add BERO
-
-extern const uint8_t ff_reverse[256];
-
-#if defined(ARCH_X86) || defined(ARCH_X86_64)
-// avoid +32 for shift optimization (gcc should do that ...)
-static inline int32_t NEG_SSR32( int32_t a, int8_t s){
- asm ("sarl %1, %0\n\t"
- : "+r" (a)
- : "ic" ((uint8_t)(-s))
- );
- return a;
-}
-static inline uint32_t NEG_USR32(uint32_t a, int8_t s){
- asm ("shrl %1, %0\n\t"
- : "+r" (a)
- : "ic" ((uint8_t)(-s))
- );
- return a;
-}
-#else
-# define NEG_SSR32(a,s) ((( int32_t)(a))>>(32-(s)))
-# define NEG_USR32(a,s) (((uint32_t)(a))>>(32-(s)))
-#endif
+#ifndef AVCODEC_BITSTREAM_H
+#define AVCODEC_BITSTREAM_H
-/* bit output */
+#include <stdint.h>
-/* buf and buf_end must be present and used by every alternative writer. */
-typedef struct PutBitContext {
-#ifdef ALT_BITSTREAM_WRITER
- uint8_t *buf, *buf_end;
- int index;
-#else
- uint32_t bit_buf;
- int bit_left;
- uint8_t *buf, *buf_ptr, *buf_end;
-#endif
-} PutBitContext;
+#include "libavutil/common.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/log.h"
+
+#include "mathops.h"
+#include "vlc.h"
-static inline void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
+typedef struct BitstreamContext {
+ uint64_t bits; // stores bits read from the buffer
+ const uint8_t *buffer, *buffer_end;
+ const uint8_t *ptr; // position inside a buffer
+ unsigned bits_left; // number of bits left in bits field
+ unsigned size_in_bits;
+} BitstreamContext;
+
+static inline void refill_64(BitstreamContext *bc)
{
- s->buf = buffer;
- s->buf_end = s->buf + buffer_size;
-#ifdef ALT_BITSTREAM_WRITER
- s->index=0;
- ((uint32_t*)(s->buf))[0]=0;
-// memset(buffer, 0, buffer_size);
+ if (bc->ptr >= bc->buffer_end)
+ return;
+
+#ifdef BITSTREAM_READER_LE
+ bc->bits = AV_RL64(bc->ptr);
#else
- s->buf_ptr = s->buf;
- s->bit_left=32;
- s->bit_buf=0;
+ bc->bits = AV_RB64(bc->ptr);
#endif
+ bc->ptr += 8;
+ bc->bits_left = 64;
}
-/* return the number of bits output */
-static inline int put_bits_count(PutBitContext *s)
+static inline void refill_32(BitstreamContext *bc)
{
-#ifdef ALT_BITSTREAM_WRITER
- return s->index;
+ if (bc->ptr >= bc->buffer_end)
+ return;
+
+#ifdef BITSTREAM_READER_LE
+ bc->bits = (uint64_t)AV_RL32(bc->ptr) << bc->bits_left | bc->bits;
#else
- return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left;
+ bc->bits = bc->bits | (uint64_t)AV_RB32(bc->ptr) << (32 - bc->bits_left);
#endif
+ bc->ptr += 4;
+ bc->bits_left += 32;
}
-/* pad the end of the output stream with zeros */
-static inline void flush_put_bits(PutBitContext *s)
+/* Initialize BitstreamContext. Input buffer must have an additional zero
+ * padding of AV_INPUT_BUFFER_PADDING_SIZE bytes at the end. */
+static inline int bitstream_init(BitstreamContext *bc, const uint8_t *buffer,
+ unsigned bit_size)
{
-#ifdef ALT_BITSTREAM_WRITER
- align_put_bits(s);
-#else
- s->bit_buf<<= s->bit_left;
- while (s->bit_left < 32) {
- /* XXX: should test end of buffer */
- *s->buf_ptr++=s->bit_buf >> 24;
- s->bit_buf<<=8;
- s->bit_left+=8;
+ unsigned buffer_size;
+
+ if (bit_size > INT_MAX - 7 || !buffer) {
+ buffer =
+ bc->buffer =
+ bc->ptr = NULL;
+ bc->bits_left = 0;
+ return AVERROR_INVALIDDATA;
}
- s->bit_left=32;
- s->bit_buf=0;
-#endif
-}
-
-void align_put_bits(PutBitContext *s);
-void put_string(PutBitContext * pbc, char *s, int put_zero);
-/* 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;
-#ifdef ALT_BITSTREAM_READER
- int index;
-#elif defined LIBMPEG2_BITSTREAM_READER
- uint8_t *buffer_ptr;
- uint32_t cache;
- int bit_count;
-#elif defined A32_BITSTREAM_READER
- uint32_t *buffer_ptr;
- uint32_t cache0;
- uint32_t cache1;
- int bit_count;
-#endif
- int size_in_bits;
-} GetBitContext;
-
-#define VLC_TYPE int16_t
+ buffer_size = (bit_size + 7) >> 3;
-typedef struct VLC {
- int bits;
- VLC_TYPE (*table)[2]; ///< code, bits
- int table_size, table_allocated;
-} VLC;
+ bc->buffer = buffer;
+ bc->buffer_end = buffer + buffer_size;
+ bc->ptr = bc->buffer;
+ bc->size_in_bits = bit_size;
+ bc->bits_left = 0;
+ bc->bits = 0;
-typedef struct RL_VLC_ELEM {
- int16_t level;
- int8_t len;
- uint8_t run;
-} RL_VLC_ELEM;
+ refill_64(bc);
-#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;
+ return 0;
}
-# endif
-#endif //!ARCH_X86
-#ifndef ALT_BITSTREAM_WRITER
-static inline void put_bits(PutBitContext *s, int n, unsigned int value)
+/* Initialize BitstreamContext with buffer size in bytes instead of bits. */
+static inline int bitstream_init8(BitstreamContext *bc, const uint8_t *buffer,
+ unsigned byte_size)
{
- unsigned int bit_buf;
- int bit_left;
-
-#ifdef STATS
- st_out_bit_counts[st_current_index] += n;
-#endif
- // printf("put_bits=%d %x\n", n, value);
- assert(n == 32 || value < (1U << n));
-
- bit_buf = s->bit_buf;
- bit_left = s->bit_left;
-
- // printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
- /* XXX: optimize */
- if (n < bit_left) {
- bit_buf = (bit_buf<<n) | value;
- bit_left-=n;
- } else {
- bit_buf<<=bit_left;
- bit_buf |= value >> (n - bit_left);
-#ifdef UNALIGNED_STORES_ARE_BAD
- if (3 & (intptr_t) s->buf_ptr) {
- s->buf_ptr[0] = bit_buf >> 24;
- s->buf_ptr[1] = bit_buf >> 16;
- s->buf_ptr[2] = bit_buf >> 8;
- s->buf_ptr[3] = bit_buf ;
- } else
-#endif
- *(uint32_t *)s->buf_ptr = be2me_32(bit_buf);
- //printf("bitbuf = %08x\n", bit_buf);
- s->buf_ptr+=4;
- bit_left+=32 - n;
- bit_buf = value;
- }
-
- s->bit_buf = bit_buf;
- s->bit_left = bit_left;
+ if (byte_size > INT_MAX / 8)
+ return AVERROR_INVALIDDATA;
+ return bitstream_init(bc, buffer, byte_size * 8);
}
-#endif
-
-#ifdef ALT_BITSTREAM_WRITER
-static inline void put_bits(PutBitContext *s, int n, unsigned int value)
+/* Return number of bits already read. */
+static inline int bitstream_tell(const BitstreamContext *bc)
{
-# ifdef ALIGNED_BITSTREAM_WRITER
-# if defined(ARCH_X86) || defined(ARCH_X86_64)
- asm volatile(
- "movl %0, %%ecx \n\t"
- "xorl %%eax, %%eax \n\t"
- "shrdl %%cl, %1, %%eax \n\t"
- "shrl %%cl, %1 \n\t"
- "movl %0, %%ecx \n\t"
- "shrl $3, %%ecx \n\t"
- "andl $0xFFFFFFFC, %%ecx \n\t"
- "bswapl %1 \n\t"
- "orl %1, (%2, %%ecx) \n\t"
- "bswapl %%eax \n\t"
- "addl %3, %0 \n\t"
- "movl %%eax, 4(%2, %%ecx) \n\t"
- : "=&r" (s->index), "=&r" (value)
- : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n))
- : "%eax", "%ecx"
- );
-# else
- int index= s->index;
- uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5);
-
- value<<= 32-n;
-
- ptr[0] |= be2me_32(value>>(index&31));
- ptr[1] = be2me_32(value<<(32-(index&31)));
-//if(n>24) printf("%d %d\n", n, value);
- index+= n;
- s->index= index;
-# endif
-# else //ALIGNED_BITSTREAM_WRITER
-# if defined(ARCH_X86) || defined(ARCH_X86_64)
- asm volatile(
- "movl $7, %%ecx \n\t"
- "andl %0, %%ecx \n\t"
- "addl %3, %%ecx \n\t"
- "negl %%ecx \n\t"
- "shll %%cl, %1 \n\t"
- "bswapl %1 \n\t"
- "movl %0, %%ecx \n\t"
- "shrl $3, %%ecx \n\t"
- "orl %1, (%%ecx, %2) \n\t"
- "addl %3, %0 \n\t"
- "movl $0, 4(%%ecx, %2) \n\t"
- : "=&r" (s->index), "=&r" (value)
- : "r" (s->buf), "r" (n), "0" (s->index), "1" (value)
- : "%ecx"
- );
-# else
- int index= s->index;
- uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3));
-
- ptr[0] |= be2me_32(value<<(32-n-(index&7) ));
- ptr[1] = 0;
-//if(n>24) printf("%d %d\n", n, value);
- index+= n;
- s->index= index;
-# endif
-# endif //!ALIGNED_BITSTREAM_WRITER
+ return (bc->ptr - bc->buffer) * 8 - bc->bits_left;
}
-#endif
-
-static inline uint8_t* pbBufPtr(PutBitContext *s)
+/* Return buffer size in bits. */
+static inline int bitstream_tell_size(const BitstreamContext *bc)
{
-#ifdef ALT_BITSTREAM_WRITER
- return s->buf + (s->index>>3);
-#else
- return s->buf_ptr;
-#endif
-}
-
-/**
- *
- * PutBitContext must be flushed & aligned to a byte boundary before calling this.
- */
-static inline void skip_put_bytes(PutBitContext *s, int n){
- assert((put_bits_count(s)&7)==0);
-#ifdef ALT_BITSTREAM_WRITER
- FIXME may need some cleaning of the buffer
- s->index += n<<3;
-#else
- assert(s->bit_left==32);
- s->buf_ptr += n;
-#endif
+ return bc->size_in_bits;
}
-/**
- * skips the given number of bits.
- * must only be used if the actual values in the bitstream dont matter
- */
-static inline void skip_put_bits(PutBitContext *s, int n){
-#ifdef ALT_BITSTREAM_WRITER
- s->index += n;
-#else
- s->bit_left -= n;
- s->buf_ptr-= s->bit_left>>5;
- s->bit_left &= 31;
-#endif
-}
-
-/**
- * Changes the end of the buffer.
- */
-static inline void set_put_bits_buffer_size(PutBitContext *s, int size){
- s->buf_end= s->buf + size;
-}
-
-/* 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 nest num bits
-
-SHOW_SBITS(name, gb, num)
- will return the nest num bits and do sign extension
-
-SKIP_BITS(name, gb, num)
- will skip over the next num bits
- note, this is equinvalent 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 equinvalent 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)
+/* Return the number of the bits left in a buffer. */
+static inline int bitstream_bits_left(const BitstreamContext *bc)
{
-#ifdef CONFIG_ALIGN
- const uint8_t *p=v;
- return (((p[0]<<8) | p[1])<<16) | (p[2]<<8) | (p[3]);
-#else
- return be2me_32( unaligned32(v)); //original
-#endif
+ return (bc->buffer - bc->ptr) * 8 + bc->size_in_bits + bc->bits_left;
}
-static inline int unaligned32_le(const void *v)
+static inline uint64_t get_val(BitstreamContext *bc, unsigned n)
{
-#ifdef CONFIG_ALIGN
- const uint8_t *p=v;
- return (((p[3]<<8) | p[2])<<16) | (p[1]<<8) | (p[0]);
+#ifdef BITSTREAM_READER_LE
+ uint64_t ret = bc->bits & ((UINT64_C(1) << n) - 1);
+ bc->bits >>= n;
#else
- return le2me_32( unaligned32(v)); //original
+ uint64_t ret = bc->bits >> (64 - n);
+ bc->bits <<= n;
#endif
-}
-
-#ifdef ALT_BITSTREAM_READER
-# 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)
+ bc->bits_left -= n;
-# define GET_CACHE(name, gb)\
- ((uint32_t)name##_cache)
-
-static inline int get_bits_count(GetBitContext *s){
- return s->index;
+ return ret;
}
-#elif defined LIBMPEG2_BITSTREAM_READER
-//libmpeg2 like reader
-
-# define MIN_CACHE_BITS 17
-
-# define OPEN_READER(name, gb)\
- int name##_bit_count=(gb)->bit_count;\
- int name##_cache= (gb)->cache;\
- uint8_t * name##_buffer_ptr=(gb)->buffer_ptr;\
-
-# define CLOSE_READER(name, gb)\
- (gb)->bit_count= name##_bit_count;\
- (gb)->cache= name##_cache;\
- (gb)->buffer_ptr= name##_buffer_ptr;\
-
-#ifdef LIBMPEG2_BITSTREAM_READER_HACK
-
-# define UPDATE_CACHE(name, gb)\
- if(name##_bit_count >= 0){\
- name##_cache+= (int)be2me_16(*(uint16_t*)name##_buffer_ptr) << name##_bit_count;\
- name##_buffer_ptr += 2;\
- name##_bit_count-= 16;\
- }\
-#else
+/* Return one bit from the buffer. */
+static inline unsigned bitstream_read_bit(BitstreamContext *bc)
+{
+ if (!bc->bits_left)
+ refill_64(bc);
-# define UPDATE_CACHE(name, gb)\
- if(name##_bit_count >= 0){\
- name##_cache+= ((name##_buffer_ptr[0]<<8) + name##_buffer_ptr[1]) << name##_bit_count;\
- name##_buffer_ptr+=2;\
- name##_bit_count-= 16;\
- }\
+ return get_val(bc, 1);
+}
+/* Return n bits from the buffer. n has to be in the 0-63 range. */
+static inline uint64_t bitstream_read_63(BitstreamContext *bc, unsigned n)
+{
+ uint64_t ret = 0;
+#ifdef BITSTREAM_READER_LE
+ uint64_t left = 0;
#endif
-# define SKIP_CACHE(name, gb, num)\
- name##_cache <<= (num);\
-
-# define SKIP_COUNTER(name, gb, num)\
- name##_bit_count += (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_BITS(name, gb, num)
-# define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
-
-# define SHOW_UBITS(name, gb, num)\
- NEG_USR32(name##_cache, num)
-
-# define SHOW_SBITS(name, gb, num)\
- NEG_SSR32(name##_cache, num)
-
-# define GET_CACHE(name, gb)\
- ((uint32_t)name##_cache)
+ if (!n)
+ return 0;
-static inline int get_bits_count(GetBitContext *s){
- return (s->buffer_ptr - s->buffer)*8 - 16 + s->bit_count;
-}
+ if (n > bc->bits_left) {
+ n -= bc->bits_left;
+#ifdef BITSTREAM_READER_LE
+ left = bc->bits_left;
+#endif
+ ret = get_val(bc, bc->bits_left);
+ refill_64(bc);
+ }
-#elif defined A32_BITSTREAM_READER
-
-# define MIN_CACHE_BITS 32
-
-# define OPEN_READER(name, gb)\
- int name##_bit_count=(gb)->bit_count;\
- uint32_t name##_cache0= (gb)->cache0;\
- uint32_t name##_cache1= (gb)->cache1;\
- uint32_t * name##_buffer_ptr=(gb)->buffer_ptr;\
-
-# define CLOSE_READER(name, gb)\
- (gb)->bit_count= name##_bit_count;\
- (gb)->cache0= name##_cache0;\
- (gb)->cache1= name##_cache1;\
- (gb)->buffer_ptr= name##_buffer_ptr;\
-
-# define UPDATE_CACHE(name, gb)\
- if(name##_bit_count > 0){\
- const uint32_t next= be2me_32( *name##_buffer_ptr );\
- name##_cache0 |= NEG_USR32(next,name##_bit_count);\
- name##_cache1 |= next<<name##_bit_count;\
- name##_buffer_ptr++;\
- name##_bit_count-= 32;\
- }\
-
-#if defined(ARCH_X86) || defined(ARCH_X86_64)
-# define SKIP_CACHE(name, gb, num)\
- asm(\
- "shldl %2, %1, %0 \n\t"\
- "shll %2, %1 \n\t"\
- : "+r" (name##_cache0), "+r" (name##_cache1)\
- : "Ic" ((uint8_t)num)\
- );
+#ifdef BITSTREAM_READER_LE
+ ret = get_val(bc, n) << left | ret;
#else
-# define SKIP_CACHE(name, gb, num)\
- name##_cache0 <<= (num);\
- name##_cache0 |= NEG_USR32(name##_cache1,num);\
- name##_cache1 <<= (num);
+ ret = get_val(bc, n) | ret << n;
#endif
-# define SKIP_COUNTER(name, gb, num)\
- name##_bit_count += (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_BITS(name, gb, num)
-# define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
-
-# define SHOW_UBITS(name, gb, num)\
- NEG_USR32(name##_cache0, num)
-
-# define SHOW_SBITS(name, gb, num)\
- NEG_SSR32(name##_cache0, num)
-
-# define GET_CACHE(name, gb)\
- (name##_cache0)
-
-static inline int get_bits_count(GetBitContext *s){
- return ((uint8_t*)s->buffer_ptr - s->buffer)*8 - 32 + s->bit_count;
+ return ret;
}
-#endif
+/* Return n bits from the buffer. n has to be in the 0-32 range. */
+static inline uint32_t bitstream_read(BitstreamContext *bc, unsigned n)
+{
+ if (!n)
+ return 0;
-/**
- * read mpeg1 dc style vlc (sign bit + mantisse with no MSB).
- * if MSB not set it is negative
- * @param n length in bits
- * @author BERO
- */
-static inline int get_xbits(GetBitContext *s, int n){
- register int tmp;
- register int32_t cache;
- OPEN_READER(re, s)
- UPDATE_CACHE(re, s)
- cache = GET_CACHE(re,s);
- if ((int32_t)cache<0) { //MSB=1
- tmp = NEG_USR32(cache,n);
- } else {
- // tmp = (-1<<n) | NEG_USR32(cache,n) + 1; mpeg12.c algo
- // tmp = - (NEG_USR32(cache,n) ^ ((1 << n) - 1)); h263.c algo
- tmp = - NEG_USR32(~cache,n);
+ if (n > bc->bits_left) {
+ refill_32(bc);
+ if (bc->bits_left < 32)
+ bc->bits_left = n;
}
- LAST_SKIP_BITS(re, s, n)
- CLOSE_READER(re, s)
- return tmp;
-}
-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;
+ return get_val(bc, n);
}
-/**
- * reads 0-17 bits.
- * Note, the alt bitstream reader can read upto 25 bits, but the libmpeg2 reader cant
- */
-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;
+/* Return n bits from the buffer as a signed integer.
+ * n has to be in the 0-32 range. */
+static inline int32_t bitstream_read_signed(BitstreamContext *bc, unsigned n)
+{
+ return sign_extend(bitstream_read(bc, n), n);
}
-unsigned int get_bits_long(GetBitContext *s, int n);
-
-/**
- * shows 0-17 bits.
- * Note, the alt bitstream reader can read upto 25 bits, but the libmpeg2 reader cant
- */
-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;
+static inline unsigned show_val(const BitstreamContext *bc, unsigned n)
+{
+#ifdef BITSTREAM_READER_LE
+ return bc->bits & ((UINT64_C(1) << n) - 1);
+#else
+ return bc->bits >> (64 - n);
+#endif
}
-unsigned int show_bits_long(GetBitContext *s, int n);
+/* Return n bits from the buffer, but do not change the buffer state.
+ * n has to be in the 0-32 range. */
+static inline unsigned bitstream_peek(BitstreamContext *bc, unsigned n)
+{
+ if (n > bc->bits_left)
+ refill_32(bc);
-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)
+ return show_val(bc, n);
}
-static inline unsigned int get_bits1(GetBitContext *s){
-#ifdef ALT_BITSTREAM_READER
- 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 n bits from the buffer as a signed integer, but do not change the
+ * buffer state. n has to be in the 0-32 range. */
+static inline int bitstream_peek_signed(BitstreamContext *bc, unsigned n)
+{
+ return sign_extend(bitstream_peek(bc, n), n);
+}
- return result;
+static inline void skip_remaining(BitstreamContext *bc, unsigned n)
+{
+#ifdef BITSTREAM_READER_LE
+ bc->bits >>= n;
#else
- return get_bits(s, 1);
+ bc->bits <<= n;
#endif
+ bc->bits_left -= n;
}
-static inline unsigned int show_bits1(GetBitContext *s){
- return show_bits(s, 1);
+/* Skip n bits in the buffer. */
+static inline void bitstream_skip(BitstreamContext *bc, unsigned n)
+{
+ if (n <= bc->bits_left)
+ skip_remaining(bc, n);
+ else {
+ n -= bc->bits_left;
+ skip_remaining(bc, bc->bits_left);
+ if (n >= 64) {
+ unsigned skip = n / 8;
+
+ n -= skip * 8;
+ bc->ptr += skip;
+ }
+ refill_64(bc);
+ if (n)
+ skip_remaining(bc, n);
+ }
}
-static inline void skip_bits1(GetBitContext *s){
- skip_bits(s, 1);
+/* Seek to the given bit position. */
+static inline void bitstream_seek(BitstreamContext *bc, unsigned pos)
+{
+ bc->ptr = bc->buffer;
+ bc->bits = 0;
+ bc->bits_left = 0;
+
+ bitstream_skip(bc, pos);
}
-/**
- * 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)
+/* Skip bits to a byte boundary. */
+static inline const uint8_t *bitstream_align(BitstreamContext *bc)
{
- const int buffer_size= (bit_size+7)>>3;
-
- s->buffer= buffer;
- s->size_in_bits= bit_size;
- s->buffer_end= buffer + buffer_size;
-#ifdef ALT_BITSTREAM_READER
- s->index=0;
-#elif defined LIBMPEG2_BITSTREAM_READER
-#ifdef LIBMPEG2_BITSTREAM_READER_HACK
- if ((int)buffer&1) {
- /* word alignment */
- s->cache = (*buffer++)<<24;
- s->buffer_ptr = buffer;
- s->bit_count = 16-8;
- } else
-#endif
- {
- s->buffer_ptr = buffer;
- s->bit_count = 16;
- s->cache = 0;
- }
-#elif defined A32_BITSTREAM_READER
- s->buffer_ptr = (uint32_t*)buffer;
- s->bit_count = 32;
- s->cache0 = 0;
- s->cache1 = 0;
-#endif
- {
- OPEN_READER(re, s)
- UPDATE_CACHE(re, s)
- UPDATE_CACHE(re, s)
- CLOSE_READER(re, s)
- }
-#ifdef A32_BITSTREAM_READER
- s->cache1 = 0;
-#endif
+ unsigned n = -bitstream_tell(bc) & 7;
+ if (n)
+ bitstream_skip(bc, n);
+ return bc->buffer + (bitstream_tell(bc) >> 3);
}
-int check_marker(GetBitContext *s, const char *msg);
-void align_get_bits(GetBitContext *s);
-int init_vlc(VLC *vlc, int nb_bits, int nb_codes,
- const void *bits, int bits_wrap, int bits_size,
- const void *codes, int codes_wrap, int codes_size,
- int flags);
-#define INIT_VLC_USE_STATIC 1
-#define INIT_VLC_LE 2
-void free_vlc(VLC *vlc);
-
-/**
- *
- * if the vlc code is invalid and max_depth=1 than no bits will be removed
- * if the vlc code is invalid and max_depth>1 than the number of bits removed
- * is undefined
- */
-#define GET_VLC(code, name, gb, table, bits, max_depth)\
-{\
- int n, index, nb_bits;\
-\
- index= SHOW_UBITS(name, gb, bits);\
- code = table[index][0];\
- n = table[index][1];\
-\
- if(max_depth > 1 && n < 0){\
- LAST_SKIP_BITS(name, gb, bits)\
- UPDATE_CACHE(name, gb)\
-\
- nb_bits = -n;\
-\
- index= SHOW_UBITS(name, gb, nb_bits) + code;\
- code = table[index][0];\
- n = table[index][1];\
- if(max_depth > 2 && n < 0){\
- LAST_SKIP_BITS(name, gb, nb_bits)\
- UPDATE_CACHE(name, gb)\
-\
- nb_bits = -n;\
-\
- index= SHOW_UBITS(name, gb, nb_bits) + code;\
- code = table[index][0];\
- n = table[index][1];\
- }\
- }\
- SKIP_BITS(name, gb, n)\
-}
+/* Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB).
+ * If MSB not set it is negative. */
+static inline int bitstream_read_xbits(BitstreamContext *bc, unsigned length)
+{
+ int32_t cache = bitstream_peek(bc, 32);
+ int sign = ~cache >> 31;
+ skip_remaining(bc, length);
-#define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)\
-{\
- int n, index, nb_bits;\
-\
- index= SHOW_UBITS(name, gb, bits);\
- level = table[index].level;\
- n = table[index].len;\
-\
- if(max_depth > 1 && n < 0){\
- SKIP_BITS(name, gb, bits)\
- if(need_update){\
- UPDATE_CACHE(name, gb)\
- }\
-\
- nb_bits = -n;\
-\
- index= SHOW_UBITS(name, gb, nb_bits) + level;\
- level = table[index].level;\
- n = table[index].len;\
- }\
- run= table[index].run;\
- SKIP_BITS(name, gb, n)\
+ return ((((uint32_t)(sign ^ cache)) >> (32 - length)) ^ sign) - sign;
}
-// deprecated, dont use get_vlc for new code, use get_vlc2 instead or use GET_VLC directly
-static inline int get_vlc(GetBitContext *s, VLC *vlc)
+/* Return the LUT element for the given bitstream configuration. */
+static inline int set_idx(BitstreamContext *bc, int code, int *n, int *nb_bits,
+ VLC_TYPE (*table)[2])
{
- int code;
- VLC_TYPE (*table)[2]= vlc->table;
-
- OPEN_READER(re, s)
- UPDATE_CACHE(re, s)
+ unsigned idx;
- GET_VLC(code, re, s, table, vlc->bits, 3)
+ *nb_bits = -*n;
+ idx = bitstream_peek(bc, *nb_bits) + code;
+ *n = table[idx][1];
- CLOSE_READER(re, s)
- return code;
+ return table[idx][0];
}
/**
- * parses a vlc code, faster then get_vlc()
- * @param bits is the number of bits which will be read at once, must be
- * identical to nb_bits in init_vlc()
- * @param max_depth is the number of times bits bits must be readed to completly
- * read the longest vlc code
+ * Parse a VLC code.
+ * @param bits is the number of bits which will be read at once, must be
+ * identical to nb_bits in init_vlc()
+ * @param max_depth is the number of times bits bits must be read to completely
+ * read the longest VLC code
* = (max_vlc_length + bits - 1) / bits
- */
-static always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2],
- int bits, int max_depth)
+ * If the VLC code is invalid and max_depth = 1, then no bits will be removed.
+ * If the VLC code is invalid and max_depth > 1, then the number of bits removed
+ * is undefined. */
+static inline int bitstream_read_vlc(BitstreamContext *bc, VLC_TYPE (*table)[2],
+ int bits, int max_depth)
{
- int code;
-
- OPEN_READER(re, s)
- UPDATE_CACHE(re, s)
-
- GET_VLC(code, re, s, table, bits, max_depth)
+ int nb_bits;
+ unsigned idx = bitstream_peek(bc, bits);
+ int code = table[idx][0];
+ int n = table[idx][1];
+
+ if (max_depth > 1 && n < 0) {
+ skip_remaining(bc, bits);
+ code = set_idx(bc, code, &n, &nb_bits, table);
+ if (max_depth > 2 && n < 0) {
+ skip_remaining(bc, nb_bits);
+ code = set_idx(bc, code, &n, &nb_bits, table);
+ }
+ }
+ skip_remaining(bc, n);
- CLOSE_READER(re, s)
return code;
}
-//#define TRACE
-
-#ifdef TRACE
-#include "avcodec.h"
-static inline void print_bin(int bits, int n){
- int i;
-
- for(i=n-1; i>=0; i--){
- av_log(NULL, AV_LOG_DEBUG, "%d", (bits>>i)&1);
- }
- for(i=n; i<24; i++)
- av_log(NULL, AV_LOG_DEBUG, " ");
-}
-
-static inline int get_bits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
- int r= get_bits(s, n);
-
- print_bin(r, n);
- av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d bit @%5d in %s %s:%d\n", r, n, r, get_bits_count(s)-n, file, func, line);
- return r;
-}
-static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, const char *func, int line){
- int show= show_bits(s, 24);
- int pos= get_bits_count(s);
- int r= get_vlc2(s, table, bits, max_depth);
- int len= get_bits_count(s) - pos;
- int bits2= show>>(24-len);
-
- print_bin(bits2, len);
-
- av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line);
- return r;
-}
-static inline int get_xbits_trace(GetBitContext *s, int n, char *file, const char *func, int line){
- int show= show_bits(s, n);
- int r= get_xbits(s, n);
-
- print_bin(show, n);
- av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d xbt @%5d in %s %s:%d\n", show, n, r, get_bits_count(s)-n, file, func, line);
- return r;
+#define BITSTREAM_RL_VLC(level, run, bc, table, bits, max_depth) \
+ do { \
+ int n, nb_bits; \
+ unsigned index = bitstream_peek(bc, bits); \
+ level = table[index].level; \
+ n = table[index].len; \
+ \
+ if (max_depth > 1 && n < 0) { \
+ bitstream_skip(bc, bits); \
+ \
+ nb_bits = -n; \
+ \
+ index = bitstream_peek(bc, nb_bits) + level; \
+ level = table[index].level; \
+ n = table[index].len; \
+ if (max_depth > 2 && n < 0) { \
+ bitstream_skip(bc, nb_bits); \
+ nb_bits = -n; \
+ \
+ index = bitstream_peek(bc, nb_bits) + level; \
+ level = table[index].level; \
+ n = table[index].len; \
+ } \
+ } \
+ run = table[index].run; \
+ bitstream_skip(bc, n); \
+ } while (0)
+
+/* Return decoded truncated unary code for the values 0, 1, 2. */
+static inline int bitstream_decode012(BitstreamContext *bc)
+{
+ if (!bitstream_read_bit(bc))
+ return 0;
+ else
+ return bitstream_read_bit(bc) + 1;
}
-#define get_bits(s, n) get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
-#define get_bits1(s) get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__)
-#define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__)
-#define get_vlc(s, vlc) get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__)
-#define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__)
-
-#define tprintf(...) av_log(NULL, AV_LOG_DEBUG, __VA_ARGS__)
-
-#else //TRACE
-#define tprintf(...) {}
-#endif
-
-static inline int decode012(GetBitContext *gb){
- int n;
- n = get_bits1(gb);
- if (n == 0)
+/* Return decoded truncated unary code for the values 2, 1, 0. */
+static inline int bitstream_decode210(BitstreamContext *bc)
+{
+ if (bitstream_read_bit(bc))
return 0;
else
- return get_bits1(gb) + 1;
+ return 2 - bitstream_read_bit(bc);
+}
+
+/* Read sign bit and flip the sign of the provided value accordingly. */
+static inline int bitstream_apply_sign(BitstreamContext *bc, int val)
+{
+ int sign = bitstream_read_signed(bc, 1);
+ return (val ^ sign) - sign;
}
-#endif /* BITSTREAM_H */
+#endif /* AVCODEC_BITSTREAM_H */