/*
 * decode.c
 * Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org>
 * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
 *
 * This file is part of mpeg2dec, a free MPEG-2 video stream decoder.
 * See http://libmpeg2.sourceforge.net/ for updates.
 *
 * mpeg2dec is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * mpeg2dec 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "plugin.h"

#include "mpeg2dec_config.h"

extern struct plugin_api* rb;

#include "mpeg2.h"
#include "attributes.h"
#include "mpeg2_internal.h"

#define BUFFER_SIZE (1194 * 1024)

#ifdef CPU_COLDFIRE
/* twice as large as on other targets because coldfire uses
 * a secondary, transposed buffer for optimisation */
static int16_t static_dct_block[128] IBSS_ATTR ATTR_ALIGN(16);
#endif

const mpeg2_info_t * mpeg2_info (mpeg2dec_t * mpeg2dec)
{
    return &mpeg2dec->info;
}

static inline int skip_chunk (mpeg2dec_t * mpeg2dec, int bytes)
{
    uint8_t * current;
    uint32_t shift;
    uint8_t * limit;
    uint8_t byte;

    if (!bytes)
	    return 0;

    current = mpeg2dec->buf_start;
    shift = mpeg2dec->shift;
    limit = current + bytes;

    do
    {
    	byte = *current++;

    	if (shift == 0x00000100)
        {
    	    int skipped;

    	    mpeg2dec->shift = 0xffffff00;
    	    skipped = current - mpeg2dec->buf_start;
    	    mpeg2dec->buf_start = current;

    	    return skipped;
    	}

    	shift = (shift | byte) << 8;
    }
    while (current < limit);

    mpeg2dec->shift = shift;
    mpeg2dec->buf_start = current;

    return 0;
}

static inline int copy_chunk (mpeg2dec_t * mpeg2dec, int bytes)
{
    uint8_t * current;
    uint32_t shift;
    uint8_t * chunk_ptr;
    uint8_t * limit;
    uint8_t byte;

    if (!bytes)
	    return 0;

    current = mpeg2dec->buf_start;
    shift = mpeg2dec->shift;
    chunk_ptr = mpeg2dec->chunk_ptr;
    limit = current + bytes;

    do
    {
    	byte = *current++;

    	if (shift == 0x00000100)
        {
    	    int copied;

    	    mpeg2dec->shift = 0xffffff00;
    	    mpeg2dec->chunk_ptr = chunk_ptr + 1;
    	    copied = current - mpeg2dec->buf_start;
    	    mpeg2dec->buf_start = current;
    	    return copied;
    	}

    	shift = (shift | byte) << 8;
    	*chunk_ptr++ = byte;
    }
    while (current < limit);

    mpeg2dec->shift = shift;
    mpeg2dec->buf_start = current;
    return 0;
}

void mpeg2_buffer (mpeg2dec_t * mpeg2dec, uint8_t * start, uint8_t * end)
{
    mpeg2dec->buf_start = start;
    mpeg2dec->buf_end = end;
}

int mpeg2_getpos (mpeg2dec_t * mpeg2dec)
{
    return mpeg2dec->buf_end - mpeg2dec->buf_start;
}

static inline mpeg2_state_t seek_chunk (mpeg2dec_t * mpeg2dec)
{
    int size, skipped;

    size = mpeg2dec->buf_end - mpeg2dec->buf_start;
    skipped = skip_chunk (mpeg2dec, size);

    if (!skipped)
    {
    	mpeg2dec->bytes_since_tag += size;
    	return STATE_BUFFER;
    }

    mpeg2dec->bytes_since_tag += skipped;
    mpeg2dec->code = mpeg2dec->buf_start[-1];

    return (mpeg2_state_t)-1;
}

mpeg2_state_t mpeg2_seek_header (mpeg2dec_t * mpeg2dec)
{
    while (mpeg2dec->code != 0xb3 &&
	       ((mpeg2dec->code != 0xb7 &&
             mpeg2dec->code != 0xb8 &&
             mpeg2dec->code) ||
             mpeg2dec->sequence.width == (unsigned)-1))
    {
    	if (seek_chunk (mpeg2dec) == STATE_BUFFER)
    	    return STATE_BUFFER;
    }

    mpeg2dec->chunk_start =
    mpeg2dec->chunk_ptr = mpeg2dec->chunk_buffer;

    mpeg2dec->user_data_len = 0;

    return mpeg2dec->code ?
                mpeg2_parse_header(mpeg2dec) :
 	            mpeg2_header_picture_start(mpeg2dec);
}

#define RECEIVED(code,state) (((state) << 8) + (code))

mpeg2_state_t mpeg2_parse (mpeg2dec_t * mpeg2dec)
{
    int size_buffer, size_chunk, copied;

    if (mpeg2dec->action)
    {
    	mpeg2_state_t state;

    	state = mpeg2dec->action (mpeg2dec);

	    if ((int)state >= 0)
	        return state;
    }

    while (1)
    {
    	while ((unsigned) (mpeg2dec->code - mpeg2dec->first_decode_slice) <
    	       mpeg2dec->nb_decode_slices)
        {
    	    size_buffer = mpeg2dec->buf_end - mpeg2dec->buf_start;
    	    size_chunk = mpeg2dec->chunk_buffer + BUFFER_SIZE -
      			         mpeg2dec->chunk_ptr;

    	    if (size_buffer <= size_chunk)
            {
        		copied = copy_chunk (mpeg2dec, size_buffer);

        		if (!copied)
                {
		            mpeg2dec->bytes_since_tag += size_buffer;
		            mpeg2dec->chunk_ptr += size_buffer;
		            return STATE_BUFFER;
		        }
	        }
            else
            {
		        copied = copy_chunk (mpeg2dec, size_chunk);

		        if (!copied)
                {
        		    /* filled the chunk buffer without finding a start code */
        		    mpeg2dec->bytes_since_tag += size_chunk;
        		    mpeg2dec->action = seek_chunk;
        		    return STATE_INVALID;
        		}
    	    }

    	    mpeg2dec->bytes_since_tag += copied;

    	    mpeg2_slice (&mpeg2dec->decoder, mpeg2dec->code,
			             mpeg2dec->chunk_start);
	        mpeg2dec->code = mpeg2dec->buf_start[-1];
	        mpeg2dec->chunk_ptr = mpeg2dec->chunk_start;
	    }

    	if ((unsigned) (mpeg2dec->code - 1) >= 0xb0 - 1)
	        break;

    	if (seek_chunk (mpeg2dec) == STATE_BUFFER)
    	    return STATE_BUFFER;
    }

    switch (mpeg2dec->code)
    {
    case 0x00:
    	mpeg2dec->action = mpeg2_header_picture_start;
    	return mpeg2dec->state;
    case 0xb7:
    	mpeg2dec->action = mpeg2_header_end;
    	break;
    case 0xb3:
    case 0xb8:
    	mpeg2dec->action = mpeg2_parse_header;
    	break;
    default:
    	mpeg2dec->action = seek_chunk;
    	return STATE_INVALID;
    }

    return (mpeg2dec->state == STATE_SLICE) ? STATE_SLICE : STATE_INVALID;
}

mpeg2_state_t mpeg2_parse_header (mpeg2dec_t * mpeg2dec)
{
    static int (* const process_header[9]) (mpeg2dec_t *) =
    {
	    mpeg2_header_picture,
        mpeg2_header_extension,
        mpeg2_header_user_data,
	    mpeg2_header_sequence,
        NULL,
        NULL,
        NULL,
        NULL,
        mpeg2_header_gop
    };

    int size_buffer, size_chunk, copied;

    mpeg2dec->action = mpeg2_parse_header;
    mpeg2dec->info.user_data = NULL;
	mpeg2dec->info.user_data_len = 0;

    while (1)
    {
    	size_buffer = mpeg2dec->buf_end - mpeg2dec->buf_start;
    	size_chunk = mpeg2dec->chunk_buffer + BUFFER_SIZE -
    		            mpeg2dec->chunk_ptr;

    	if (size_buffer <= size_chunk)
        {
    	    copied = copy_chunk (mpeg2dec, size_buffer);

    	    if (!copied)
            {
        		mpeg2dec->bytes_since_tag += size_buffer;
        		mpeg2dec->chunk_ptr += size_buffer;
        		return STATE_BUFFER;
    	    }
    	}
        else
        {
    	    copied = copy_chunk (mpeg2dec, size_chunk);

    	    if (!copied)
            {
        		/* filled the chunk buffer without finding a start code */
        		mpeg2dec->bytes_since_tag += size_chunk;
        		mpeg2dec->code = 0xb4;
        		mpeg2dec->action = mpeg2_seek_header;
        		return STATE_INVALID;
    	    }
    	}

    	mpeg2dec->bytes_since_tag += copied;

    	if (process_header[mpeg2dec->code & 0x0b] (mpeg2dec))
        {
    	    mpeg2dec->code = mpeg2dec->buf_start[-1];
    	    mpeg2dec->action = mpeg2_seek_header;
    	    return STATE_INVALID;
    	}

    	mpeg2dec->code = mpeg2dec->buf_start[-1];

    	switch (RECEIVED (mpeg2dec->code, mpeg2dec->state))
        {
    	/* state transition after a sequence header */
    	case RECEIVED (0x00, STATE_SEQUENCE):
    	    mpeg2dec->action = mpeg2_header_picture_start;
    	case RECEIVED (0xb8, STATE_SEQUENCE):
    	    mpeg2_header_sequence_finalize (mpeg2dec);
    	    break;

    	/* other legal state transitions */
    	case RECEIVED (0x00, STATE_GOP):
    	    mpeg2_header_gop_finalize (mpeg2dec);
    	    mpeg2dec->action = mpeg2_header_picture_start;
    	    break;
    	case RECEIVED (0x01, STATE_PICTURE):
    	case RECEIVED (0x01, STATE_PICTURE_2ND):
    	    mpeg2_header_picture_finalize (mpeg2dec);
    	    mpeg2dec->action = mpeg2_header_slice_start;
    	    break;

    	/* legal headers within a given state */
    	case RECEIVED (0xb2, STATE_SEQUENCE):
    	case RECEIVED (0xb2, STATE_GOP):
    	case RECEIVED (0xb2, STATE_PICTURE):
    	case RECEIVED (0xb2, STATE_PICTURE_2ND):
    	case RECEIVED (0xb5, STATE_SEQUENCE):
    	case RECEIVED (0xb5, STATE_PICTURE):
    	case RECEIVED (0xb5, STATE_PICTURE_2ND):
    	    mpeg2dec->chunk_ptr = mpeg2dec->chunk_start;
    	    continue;

    	default:
    	    mpeg2dec->action = mpeg2_seek_header;
    	    return STATE_INVALID;
    	}

    	mpeg2dec->chunk_start = mpeg2dec->chunk_ptr = mpeg2dec->chunk_buffer;
    	mpeg2dec->user_data_len = 0;

    	return mpeg2dec->state;
    }
}

int mpeg2_convert (mpeg2dec_t * mpeg2dec, mpeg2_convert_t convert, void * arg)
{
    mpeg2_convert_init_t convert_init;
    int error;

    error = convert (MPEG2_CONVERT_SET, NULL, &mpeg2dec->sequence, 0,
		             arg, &convert_init);

    if (!error)
    {
    	mpeg2dec->convert = convert;
    	mpeg2dec->convert_arg = arg;
    	mpeg2dec->convert_id_size = convert_init.id_size;
    	mpeg2dec->convert_stride = 0;
    }

    return error;
}

int mpeg2_stride (mpeg2dec_t * mpeg2dec, int stride)
{
    if (!mpeg2dec->convert)
    {
    	if (stride < (int) mpeg2dec->sequence.width)
    	    stride = mpeg2dec->sequence.width;

    	mpeg2dec->decoder.stride_frame = stride;
    }
    else
    {
    	mpeg2_convert_init_t convert_init;

    	stride = mpeg2dec->convert(MPEG2_CONVERT_STRIDE, NULL,
        				           &mpeg2dec->sequence, stride,
               				       mpeg2dec->convert_arg,
    				               &convert_init);

    	mpeg2dec->convert_id_size = convert_init.id_size;
    	mpeg2dec->convert_stride = stride;
    }

    return stride;
}

void mpeg2_set_buf (mpeg2dec_t * mpeg2dec, uint8_t * buf[3], void * id)
{
    mpeg2_fbuf_t * fbuf;

    if (mpeg2dec->custom_fbuf)
    {
    	if (mpeg2dec->state == STATE_SEQUENCE)
        {
    	    mpeg2dec->fbuf[2] = mpeg2dec->fbuf[1];
    	    mpeg2dec->fbuf[1] = mpeg2dec->fbuf[0];
    	}

    	mpeg2_set_fbuf (mpeg2dec, (mpeg2dec->decoder.coding_type ==
    				   PIC_FLAG_CODING_TYPE_B));

    	fbuf = mpeg2dec->fbuf[0];
    }
    else
    {
    	fbuf = &mpeg2dec->fbuf_alloc[mpeg2dec->alloc_index].fbuf;
    	mpeg2dec->alloc_index_user = ++mpeg2dec->alloc_index;
    }

    fbuf->buf[0] = buf[0];
    fbuf->buf[1] = buf[1];
    fbuf->buf[2] = buf[2];

    fbuf->id = id;
}

void mpeg2_custom_fbuf (mpeg2dec_t * mpeg2dec, int custom_fbuf)
{
    mpeg2dec->custom_fbuf = custom_fbuf;
}

void mpeg2_skip (mpeg2dec_t * mpeg2dec, int skip)
{
    mpeg2dec->first_decode_slice = 1;
    mpeg2dec->nb_decode_slices = skip ? 0 : (0xb0 - 1);
}

void mpeg2_slice_region (mpeg2dec_t * mpeg2dec, int start, int end)
{
    start = (start < 1) ? 1 : (start > 0xb0) ? 0xb0 : start;
    end = (end < start) ? start : (end > 0xb0) ? 0xb0 : end;
    mpeg2dec->first_decode_slice = start;
    mpeg2dec->nb_decode_slices = end - start;
}

void mpeg2_tag_picture (mpeg2dec_t * mpeg2dec, uint32_t tag, uint32_t tag2)
{
    mpeg2dec->tag_previous = mpeg2dec->tag_current;
    mpeg2dec->tag2_previous = mpeg2dec->tag2_current;
    mpeg2dec->tag_current = tag;
    mpeg2dec->tag2_current = tag2;
    mpeg2dec->num_tags++;
    mpeg2dec->bytes_since_tag = 0;
}

void mpeg2_reset (mpeg2dec_t * mpeg2dec, int full_reset)
{
    mpeg2dec->buf_start = mpeg2dec->buf_end = NULL;
    mpeg2dec->num_tags = 0;
    mpeg2dec->shift = 0xffffff00;
    mpeg2dec->code = 0xb4;
    mpeg2dec->action = mpeg2_seek_header;
    mpeg2dec->state = STATE_INVALID;
    mpeg2dec->first = 1;

    mpeg2_reset_info(&mpeg2dec->info);
    mpeg2dec->info.gop = NULL;
    mpeg2dec->info.user_data = NULL;
    mpeg2dec->info.user_data_len = 0;

    if (full_reset)
    {
    	mpeg2dec->info.sequence = NULL;
    	mpeg2_header_state_init (mpeg2dec);
    }
}

mpeg2dec_t * mpeg2_init (void)
{
    mpeg2dec_t * mpeg2dec;

    mpeg2_idct_init ();

    mpeg2dec = (mpeg2dec_t *)mpeg2_bufalloc(sizeof (mpeg2dec_t),
					                        MPEG2_ALLOC_MPEG2DEC);
    if (mpeg2dec == NULL)
	    return NULL;

#ifdef CPU_COLDFIRE
    mpeg2dec->decoder.DCTblock = static_dct_block;
#endif

    rb->memset (mpeg2dec->decoder.DCTblock, 0, 64 * sizeof (int16_t));
    rb->memset (mpeg2dec->quantizer_matrix, 0, 4 * 64 * sizeof (uint8_t));

    mpeg2dec->chunk_buffer = (uint8_t *)mpeg2_bufalloc(BUFFER_SIZE + 4,
						                               MPEG2_ALLOC_CHUNK);

    mpeg2dec->sequence.width = (unsigned)-1;
    mpeg2_reset (mpeg2dec, 1);

    return mpeg2dec;
}

void mpeg2_close (mpeg2dec_t * mpeg2dec)
{
    mpeg2_header_state_init (mpeg2dec);
#if 0
    /* These are dedicated buffers in rockbox */
    mpeg2_free (mpeg2dec->chunk_buffer);
    mpeg2_free (mpeg2dec);
#endif
}