/*
 * copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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.
 *
 * FFmpeg 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 FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file libavcodec/get_bits.h
 * bitstream reader API header.
 */

#ifndef AVCODEC_GET_BITS_H
#define AVCODEC_GET_BITS_H

#include "mathops.h"
#include "bswap.h"
//#include <ffmpeg/libavutil/common.h>
#include "intreadwrite.h"
//#include <core/dsp.h>
#ifdef ANDROID
#include <android/log.h>

#define  LOG_TAG    "get_bits"
#endif
#define LOGD printf
//goes the  A32_BITSTREAM_READER passage
#if defined(ALT_BITSTREAM_READER_LE) && !defined(ALT_BITSTREAM_READER)
#define ALT_BITSTREAM_READER
#endif

#if !defined(LIBMPEG2_BITSTREAM_READER) && !defined(A32_BITSTREAM_READER) && !defined(ALT_BITSTREAM_READER)
#if defined(ARCH_ARM) && !defined(HAVE_FAST_UNALIGNED)
#define A32_BITSTREAM_READER
#else
#define ALT_BITSTREAM_READER
//#define LIBMPEG2_BITSTREAM_READER
//#define A32_BITSTREAM_READER
#endif
#endif

#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;
#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;


/* Bitstream reader API docs:
name
    arbitrary 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 LAST_SKIP_CACHE; SKIP_COUNTER

for examples see get_bits, show_bits, skip_bits, get_vlc
*/

#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= AV_RL32( ((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= AV_RB32( ((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)))

#define SHOW_SBITS(name, gb, num)\
        NEG_SSR32((name##_cache)<<(32-(num)), num)
#else
#define SHOW_UBITS(name, gb, num)\
        NEG_USR32(name##_cache, num)

#define SHOW_SBITS(name, gb, num)\
        NEG_SSR32(name##_cache, num)
#endif

#define GET_CACHE(name, gb)\
        ((uint32_t)name##_cache)

static inline int get_bits_count(GetBitContext *s)
{
    return s->index;
}

static inline void skip_bits_long(GetBitContext *s, int n)
{
    s->index += n;
}

#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;\

#define UPDATE_CACHE(name, gb)\
    if(name##_bit_count >= 0){\
        name##_cache+= AV_RB16(name##_buffer_ptr) << name##_bit_count; \
        name##_buffer_ptr+=2;\
        name##_bit_count-= 16;\
    }\

#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)

static inline int get_bits_count(GetBitContext *s)
{
    return (s->buffer_ptr - s->buffer) * 8 - 16 + s->bit_count;
}

static inline void skip_bits_long(GetBitContext *s, int n)
{
    OPEN_READER(re, s)
    re_bit_count += n;
    re_buffer_ptr += 2 * (re_bit_count >> 4);
    re_bit_count &= 15;
    re_cache = ((re_buffer_ptr[-2] << 8) + re_buffer_ptr[-1]) << (16 + re_bit_count);
    UPDATE_CACHE(re, s)
    CLOSE_READER(re, s)
}

#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 ARCH_X86
#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))\
           );
#else
#define SKIP_CACHE(name, gb, num)\
        name##_cache0 <<= (num);\
        name##_cache0 |= NEG_USR32(name##_cache1,num);\
        name##_cache1 <<= (num);
#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;
}

static inline void skip_bits_long(GetBitContext *s, int n)
{
    OPEN_READER(re, s)
    re_bit_count += n;
    re_buffer_ptr += re_bit_count >> 5;
    re_bit_count &= 31;
    re_cache0 = be2me_32(re_buffer_ptr[-1]) << re_bit_count;
    re_cache1 = 0;
    UPDATE_CACHE(re, s)
    CLOSE_READER(re, s)
}

#endif

/**
 * 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 sign;
    register int32_t cache;
    OPEN_READER(re, s)
    UPDATE_CACHE(re, s)
    cache = GET_CACHE(re, s);
    sign = (~cache) >> 31;
    LAST_SKIP_BITS(re, s, n)
    CLOSE_READER(re, s)
    return (NEG_USR32(sign ^ cache, n) ^ sign) - sign;
}

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 1-17 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;
}

/**
 * shows 1-17 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;
}

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)
{
#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 result;
#else
    return get_bits(s, 1);
#endif
}

static inline unsigned int show_bits1(GetBitContext *s)
{
    return show_bits(s, 1);
}

static inline void skip_bits1(GetBitContext *s)
{
    skip_bits(s, 1);
}

/**
 * reads 0-32 bits.
 */
static inline unsigned int get_bits_long(GetBitContext *s, int n)
{
    if (n <= 17) {
        return get_bits(s, n);
    } else {
#ifdef ALT_BITSTREAM_READER_LE
        int ret = get_bits(s, 16);
        return ret | (get_bits(s, n - 16) << 16);
#else
        int ret = get_bits(s, 16) << (n - 16);
        return ret | get_bits(s, n - 16);
#endif
    }
}

/**
 * reads 0-32 bits as a signed integer.
 */
static inline int get_sbits_long(GetBitContext *s, int n)
{
    return sign_extend(get_bits_long(s, n), n);
}

/**
 * shows 0-32 bits.
 */
static inline unsigned int show_bits_long(GetBitContext *s, int n)
{
    if (n <= 17) {
        return show_bits(s, n);
    } else {
        GetBitContext gb = *s;
        return get_bits_long(&gb, n);
    }
}

static inline int check_marker(GetBitContext *s, const char *msg)
{
    int bit = get_bits1(s);
    if (!bit) {
        LOGD("Marker bit missing %s\n", msg);
    }

    return bit;
}

/**
 * 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
 *
 * While GetBitContext stores the buffer size, for performance reasons you are
 * responsible for checking for the buffer end yourself (take advantage of the padding)!
 */
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 = NULL;
    }

    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
    s->buffer_ptr = (uint8_t*)((intptr_t)buffer & (~1));
    s->bit_count = 16 + 8 * ((intptr_t)buffer & 1);
    skip_bits_long(s, 0);
#elif defined A32_BITSTREAM_READER
    s->buffer_ptr = (uint32_t*)((intptr_t)buffer & (~3));
    s->bit_count = 32 + 8 * ((intptr_t)buffer & 3);
    skip_bits_long(s, 0);
#endif
}

static inline void align_get_bits(GetBitContext *s)
{
    int n = (-get_bits_count(s)) & 7;
    if (n) {
        skip_bits(s, n);
    }
}

//#define TRACE

#ifdef TRACE
static inline void print_bin(int bits, int n)
{
    int i;

    for (i = n - 1; i >= 0; i--) {
        LOGD("%d", (bits >> i) & 1);
    }
    for (i = n; i < 24; i++) {
        LOGD(" ");
    }
}

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);
    LOGD("%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_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);
    LOGD("%5d %2d %3d xbt @%5d in %s %s:%d\n", show, n, r, get_bits_count(s) - n, file, func, line);
    return r;
}

#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__)
#endif

static inline int get_bits_left(GetBitContext *gb)
{
    return gb->size_in_bits - get_bits_count(gb);
}

#endif /* AVCODEC_GET_BITS_H */