/*
  * Sierra VMD Audio & Video Decoders
  * Copyright (C) 2004 the ffmpeg project
  *

  * 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/vmdav.c

  * Sierra VMD audio & video decoders
  * by Vladimir "VAG" Gneushev (vagsoft at mail.ru)

  * for more information on the Sierra VMD format, visit:
  *   http://www.pcisys.net/~melanson/codecs/

  *
  * The video decoder outputs PAL8 colorspace data. The decoder expects
  * a 0x330-byte VMD file header to be transmitted via extradata during
  * codec initialization. Each encoded frame that is sent to this decoder

  * is expected to be prepended with the appropriate 16-byte frame

  * information record from the VMD file.
  *
  * The audio decoder, like the video decoder, expects each encoded data

  * chunk to be prepended with the appropriate 16-byte frame information

  * record from the VMD file. It does not require the 0x330-byte VMD file
  * header, but it does need the audio setup parameters passed in through
  * normal libavcodec API means.
  */
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 

 #include "libavutil/intreadwrite.h"

 #include "avcodec.h"
 
 #define VMD_HEADER_SIZE 0x330
 #define PALETTE_COUNT 256
 
 /*
  * Video Decoder
  */
 
 typedef struct VmdVideoContext {
 
     AVCodecContext *avctx;
     AVFrame frame;
     AVFrame prev_frame;
 

     const unsigned char *buf;

     int size;
 
     unsigned char palette[PALETTE_COUNT * 4];
     unsigned char *unpack_buffer;

     int unpack_buffer_size;

     int x_off, y_off;

 } VmdVideoContext;
 
 #define QUEUE_SIZE 0x1000
 #define QUEUE_MASK 0x0FFF
 

 static void lz_unpack(const unsigned char *src, unsigned char *dest, int dest_len)

 {

     const unsigned char *s;

     unsigned char *d;

     unsigned char *d_end;

     unsigned char queue[QUEUE_SIZE];
     unsigned int qpos;
     unsigned int dataleft;
     unsigned int chainofs;
     unsigned int chainlen;
     unsigned int speclen;
     unsigned char tag;
     unsigned int i, j;
 
     s = src;
     d = dest;

     d_end = d + dest_len;

     dataleft = AV_RL32(s);

     s += 4;

     memset(queue, 0x20, QUEUE_SIZE);

     if (AV_RL32(s) == 0x56781234) {

         s += 4;
         qpos = 0x111;
         speclen = 0xF + 3;
     } else {
         qpos = 0xFEE;
         speclen = 100;  /* no speclen */
     }
 
     while (dataleft > 0) {
         tag = *s++;
         if ((tag == 0xFF) && (dataleft > 8)) {

             if (d + 8 > d_end)
                 return;

             for (i = 0; i < 8; i++) {
                 queue[qpos++] = *d++ = *s++;
                 qpos &= QUEUE_MASK;
             }
             dataleft -= 8;
         } else {
             for (i = 0; i < 8; i++) {
                 if (dataleft == 0)
                     break;
                 if (tag & 0x01) {

                     if (d + 1 > d_end)
                         return;

                     queue[qpos++] = *d++ = *s++;
                     qpos &= QUEUE_MASK;
                     dataleft--;
                 } else {
                     chainofs = *s++;
                     chainofs |= ((*s & 0xF0) << 4);
                     chainlen = (*s++ & 0x0F) + 3;
                     if (chainlen == speclen)
                         chainlen = *s++ + 0xF + 3;

                     if (d + chainlen > d_end)
                         return;

                     for (j = 0; j < chainlen; j++) {
                         *d = queue[chainofs++ & QUEUE_MASK];
                         queue[qpos++] = *d++;
                         qpos &= QUEUE_MASK;
                     }
                     dataleft -= chainlen;
                 }
                 tag >>= 1;
             }
         }
     }
 }
 

 static int rle_unpack(const unsigned char *src, unsigned char *dest,

     int src_len, int dest_len)

 {

     const unsigned char *ps;

     unsigned char *pd;
     int i, l;

     unsigned char *dest_end = dest + dest_len;

 
     ps = src;
     pd = dest;

     if (src_len & 1)

         *pd++ = *ps++;
 

     src_len >>= 1;

     i = 0;
     do {
         l = *ps++;
         if (l & 0x80) {
             l = (l & 0x7F) * 2;

             if (pd + l > dest_end)

                 return ps - src;

             memcpy(pd, ps, l);
             ps += l;
             pd += l;
         } else {

             if (pd + i > dest_end)

                 return ps - src;

             for (i = 0; i < l; i++) {
                 *pd++ = ps[0];
                 *pd++ = ps[1];
             }
             ps += 2;
         }
         i += l;

     } while (i < src_len);

     return ps - src;

 }
 
 static void vmd_decode(VmdVideoContext *s)
 {
     int i;
     unsigned int *palette32;
     unsigned char r, g, b;
 
     /* point to the start of the encoded data */

     const unsigned char *p = s->buf + 16;

     const unsigned char *pb;

     unsigned char meth;
     unsigned char *dp;   /* pointer to current frame */
     unsigned char *pp;   /* pointer to previous frame */
     unsigned char len;
     int ofs;
 
     int frame_x, frame_y;
     int frame_width, frame_height;

     int dp_size;

     frame_x = AV_RL16(&s->buf[6]);
     frame_y = AV_RL16(&s->buf[8]);
     frame_width = AV_RL16(&s->buf[10]) - frame_x + 1;
     frame_height = AV_RL16(&s->buf[12]) - frame_y + 1;

     if (frame_x < 0 || frame_width < 0 ||
         frame_x >= s->avctx->width ||
         frame_width > s->avctx->width ||
         frame_x + frame_width > s->avctx->width)
         return;
     if (frame_y < 0 || frame_height < 0 ||
         frame_y >= s->avctx->height ||
         frame_height > s->avctx->height ||
         frame_y + frame_height > s->avctx->height)
         return;

     if ((frame_width == s->avctx->width && frame_height == s->avctx->height) &&
         (frame_x || frame_y)) {
 
         s->x_off = frame_x;
         s->y_off = frame_y;
     }
     frame_x -= s->x_off;
     frame_y -= s->y_off;
 

     /* if only a certain region will be updated, copy the entire previous
      * frame before the decode */
     if (frame_x || frame_y || (frame_width != s->avctx->width) ||
         (frame_height != s->avctx->height)) {
 

         memcpy(s->frame.data[0], s->prev_frame.data[0],

             s->avctx->height * s->frame.linesize[0]);
     }
 
     /* check if there is a new palette */
     if (s->buf[15] & 0x02) {
         p += 2;
         palette32 = (unsigned int *)s->palette;
         for (i = 0; i < PALETTE_COUNT; i++) {
             r = *p++ * 4;
             g = *p++ * 4;
             b = *p++ * 4;
             palette32[i] = (r << 16) | (g << 8) | (b);
         }
         s->size -= (256 * 3 + 2);
     }
     if (s->size >= 0) {
         /* originally UnpackFrame in VAG's code */
         pb = p;
         meth = *pb++;
         if (meth & 0x80) {

             lz_unpack(pb, s->unpack_buffer, s->unpack_buffer_size);

             meth &= 0x7F;
             pb = s->unpack_buffer;
         }
 
         dp = &s->frame.data[0][frame_y * s->frame.linesize[0] + frame_x];

         dp_size = s->frame.linesize[0] * s->avctx->height;

         pp = &s->prev_frame.data[0][frame_y * s->prev_frame.linesize[0] + frame_x];
         switch (meth) {
         case 1:
             for (i = 0; i < frame_height; i++) {
                 ofs = 0;
                 do {
                     len = *pb++;
                     if (len & 0x80) {
                         len = (len & 0x7F) + 1;

                         if (ofs + len > frame_width)
                             return;

                         memcpy(&dp[ofs], pb, len);
                         pb += len;
                         ofs += len;
                     } else {
                         /* interframe pixel copy */

                         if (ofs + len + 1 > frame_width)
                             return;

                         memcpy(&dp[ofs], &pp[ofs], len + 1);
                         ofs += len + 1;
                     }
                 } while (ofs < frame_width);
                 if (ofs > frame_width) {

                     av_log(s->avctx, AV_LOG_ERROR, "VMD video: offset > width (%d > %d)\n",

                         ofs, frame_width);
                     break;
                 }
                 dp += s->frame.linesize[0];
                 pp += s->prev_frame.linesize[0];
             }
             break;
 
         case 2:
             for (i = 0; i < frame_height; i++) {
                 memcpy(dp, pb, frame_width);
                 pb += frame_width;
                 dp += s->frame.linesize[0];
                 pp += s->prev_frame.linesize[0];
             }
             break;
 
         case 3:
             for (i = 0; i < frame_height; i++) {
                 ofs = 0;
                 do {
                     len = *pb++;
                     if (len & 0x80) {
                         len = (len & 0x7F) + 1;
                         if (*pb++ == 0xFF)

                             len = rle_unpack(pb, &dp[ofs], len, frame_width - ofs);

                         else
                             memcpy(&dp[ofs], pb, len);
                         pb += len;
                         ofs += len;
                     } else {
                         /* interframe pixel copy */

                         if (ofs + len + 1 > frame_width)
                             return;

                         memcpy(&dp[ofs], &pp[ofs], len + 1);
                         ofs += len + 1;
                     }
                 } while (ofs < frame_width);
                 if (ofs > frame_width) {

                     av_log(s->avctx, AV_LOG_ERROR, "VMD video: offset > width (%d > %d)\n",

                         ofs, frame_width);
                 }
                 dp += s->frame.linesize[0];
                 pp += s->prev_frame.linesize[0];
             }
             break;
         }
     }
 }
 

 static av_cold int vmdvideo_decode_init(AVCodecContext *avctx)

 {

     VmdVideoContext *s = avctx->priv_data;

     int i;
     unsigned int *palette32;
     int palette_index = 0;
     unsigned char r, g, b;
     unsigned char *vmd_header;
     unsigned char *raw_palette;
 
     s->avctx = avctx;
     avctx->pix_fmt = PIX_FMT_PAL8;
 
     /* make sure the VMD header made it */
     if (s->avctx->extradata_size != VMD_HEADER_SIZE) {

         av_log(s->avctx, AV_LOG_ERROR, "VMD video: expected extradata size of %d\n",

             VMD_HEADER_SIZE);
         return -1;
     }
     vmd_header = (unsigned char *)avctx->extradata;
 

     s->unpack_buffer_size = AV_RL32(&vmd_header[800]);

     s->unpack_buffer = av_malloc(s->unpack_buffer_size);

     if (!s->unpack_buffer)
         return -1;
 
     /* load up the initial palette */
     raw_palette = &vmd_header[28];
     palette32 = (unsigned int *)s->palette;
     for (i = 0; i < PALETTE_COUNT; i++) {
         r = raw_palette[palette_index++] * 4;
         g = raw_palette[palette_index++] * 4;
         b = raw_palette[palette_index++] * 4;
         palette32[i] = (r << 16) | (g << 8) | (b);
     }
 
     s->frame.data[0] = s->prev_frame.data[0] = NULL;
 
     return 0;
 }
 
 static int vmdvideo_decode_frame(AVCodecContext *avctx,
                                  void *data, int *data_size,

                                  const uint8_t *buf, int buf_size)

 {

     VmdVideoContext *s = avctx->priv_data;

 
     s->buf = buf;
     s->size = buf_size;
 

     if (buf_size < 16)
         return buf_size;
 

     s->frame.reference = 1;
     if (avctx->get_buffer(avctx, &s->frame)) {

         av_log(s->avctx, AV_LOG_ERROR, "VMD Video: get_buffer() failed\n");

         return -1;
     }
 
     vmd_decode(s);
 
     /* make the palette available on the way out */
     memcpy(s->frame.data[1], s->palette, PALETTE_COUNT * 4);
 
     /* shuffle frames */

     FFSWAP(AVFrame, s->frame, s->prev_frame);
     if (s->frame.data[0])
         avctx->release_buffer(avctx, &s->frame);

 
     *data_size = sizeof(AVFrame);

     *(AVFrame*)data = s->prev_frame;

 
     /* report that the buffer was completely consumed */
     return buf_size;
 }
 

 static av_cold int vmdvideo_decode_end(AVCodecContext *avctx)

 {

     VmdVideoContext *s = avctx->priv_data;

 
     if (s->prev_frame.data[0])
         avctx->release_buffer(avctx, &s->prev_frame);
     av_free(s->unpack_buffer);
 
     return 0;
 }
 
 
 /*
  * Audio Decoder
  */
 
 typedef struct VmdAudioContext {

     AVCodecContext *avctx;

     int channels;
     int bits;
     int block_align;

     int predictors[2];

 } VmdAudioContext;
 

 static const uint16_t vmdaudio_table[128] = {

     0x000, 0x008, 0x010, 0x020, 0x030, 0x040, 0x050, 0x060, 0x070, 0x080,
     0x090, 0x0A0, 0x0B0, 0x0C0, 0x0D0, 0x0E0, 0x0F0, 0x100, 0x110, 0x120,
     0x130, 0x140, 0x150, 0x160, 0x170, 0x180, 0x190, 0x1A0, 0x1B0, 0x1C0,
     0x1D0, 0x1E0, 0x1F0, 0x200, 0x208, 0x210, 0x218, 0x220, 0x228, 0x230,
     0x238, 0x240, 0x248, 0x250, 0x258, 0x260, 0x268, 0x270, 0x278, 0x280,
     0x288, 0x290, 0x298, 0x2A0, 0x2A8, 0x2B0, 0x2B8, 0x2C0, 0x2C8, 0x2D0,
     0x2D8, 0x2E0, 0x2E8, 0x2F0, 0x2F8, 0x300, 0x308, 0x310, 0x318, 0x320,
     0x328, 0x330, 0x338, 0x340, 0x348, 0x350, 0x358, 0x360, 0x368, 0x370,
     0x378, 0x380, 0x388, 0x390, 0x398, 0x3A0, 0x3A8, 0x3B0, 0x3B8, 0x3C0,
     0x3C8, 0x3D0, 0x3D8, 0x3E0, 0x3E8, 0x3F0, 0x3F8, 0x400, 0x440, 0x480,
     0x4C0, 0x500, 0x540, 0x580, 0x5C0, 0x600, 0x640, 0x680, 0x6C0, 0x700,
     0x740, 0x780, 0x7C0, 0x800, 0x900, 0xA00, 0xB00, 0xC00, 0xD00, 0xE00,
     0xF00, 0x1000, 0x1400, 0x1800, 0x1C00, 0x2000, 0x3000, 0x4000
 };
 

 static av_cold int vmdaudio_decode_init(AVCodecContext *avctx)

 {

     VmdAudioContext *s = avctx->priv_data;

     s->avctx = avctx;

     s->channels = avctx->channels;

     s->bits = avctx->bits_per_coded_sample;

     s->block_align = avctx->block_align;

     avctx->sample_fmt = SAMPLE_FMT_S16;

     av_log(s->avctx, AV_LOG_DEBUG, "%d channels, %d bits/sample, block align = %d, sample rate = %d\n",

             s->channels, s->bits, s->block_align, avctx->sample_rate);

 
     return 0;
 }
 
 static void vmdaudio_decode_audio(VmdAudioContext *s, unsigned char *data,

     const uint8_t *buf, int buf_size, int stereo)

 {
     int i;
     int chan = 0;
     int16_t *out = (int16_t*)data;

     for(i = 0; i < buf_size; i++) {

         if(buf[i] & 0x80)
             s->predictors[chan] -= vmdaudio_table[buf[i] & 0x7F];
         else
             s->predictors[chan] += vmdaudio_table[buf[i]];

         s->predictors[chan] = av_clip_int16(s->predictors[chan]);

         out[i] = s->predictors[chan];
         chan ^= stereo;
     }

 }
 

 static int vmdaudio_loadsound(VmdAudioContext *s, unsigned char *data,

     const uint8_t *buf, int silence, int data_size)

 {

     int bytes_decoded = 0;
     int i;
 

 //    if (silence)
 //        av_log(s->avctx, AV_LOG_INFO, "silent block!\n");

     if (s->channels == 2) {

 
         /* stereo handling */

         if (silence) {

             memset(data, 0, data_size * 2);

         } else {

             if (s->bits == 16)

                 vmdaudio_decode_audio(s, data, buf, data_size, 1);

             else {

                 /* copy the data but convert it to signed */

                 for (i = 0; i < data_size; i++){

                     *data++ = buf[i] + 0x80;
                     *data++ = buf[i] + 0x80;
                 }
             }

         }
     } else {

         bytes_decoded = data_size * 2;

 
         /* mono handling */
         if (silence) {

             memset(data, 0, data_size * 2);

         } else {

             if (s->bits == 16) {

                 vmdaudio_decode_audio(s, data, buf, data_size, 0);

             } else {

                 /* copy the data but convert it to signed */

                 for (i = 0; i < data_size; i++){

                     *data++ = buf[i] + 0x80;
                     *data++ = buf[i] + 0x80;
                 }

             }
         }

     }

     return data_size * 2;

 }
 
 static int vmdaudio_decode_frame(AVCodecContext *avctx,
                                  void *data, int *data_size,

                                  const uint8_t *buf, int buf_size)

 {

     VmdAudioContext *s = avctx->priv_data;

     unsigned char *output_samples = (unsigned char *)data;
 
     /* point to the start of the encoded data */

     const unsigned char *p = buf + 16;

     if (buf_size < 16)
         return buf_size;
 

     if (buf[6] == 1) {
         /* the chunk contains audio */

         *data_size = vmdaudio_loadsound(s, output_samples, p, 0, buf_size - 16);

     } else if (buf[6] == 2) {

         /* initial chunk, may contain audio and silence */
         uint32_t flags = AV_RB32(p);
         int raw_block_size = s->block_align * s->bits / 8;
         int silent_chunks;
         if(flags == 0xFFFFFFFF)
             silent_chunks = 32;
         else
             silent_chunks = av_log2(flags + 1);
         if(*data_size < (s->block_align*silent_chunks + buf_size - 20) * 2)
             return -1;
         *data_size = 0;
         memset(output_samples, 0, raw_block_size * silent_chunks);
         output_samples += raw_block_size * silent_chunks;
         *data_size = raw_block_size * silent_chunks;
         *data_size += vmdaudio_loadsound(s, output_samples, p + 4, 0, buf_size - 20);

     } else if (buf[6] == 3) {
         /* silent chunk */

         *data_size = vmdaudio_loadsound(s, output_samples, p, 1, 0);

     }
 
     return buf_size;
 }
 
 
 /*
  * Public Data Structures
  */
 
 AVCodec vmdvideo_decoder = {
     "vmdvideo",
     CODEC_TYPE_VIDEO,
     CODEC_ID_VMDVIDEO,
     sizeof(VmdVideoContext),
     vmdvideo_decode_init,
     NULL,
     vmdvideo_decode_end,
     vmdvideo_decode_frame,
     CODEC_CAP_DR1,

     .long_name = NULL_IF_CONFIG_SMALL("Sierra VMD video"),

 };
 
 AVCodec vmdaudio_decoder = {
     "vmdaudio",
     CODEC_TYPE_AUDIO,
     CODEC_ID_VMDAUDIO,
     sizeof(VmdAudioContext),
     vmdaudio_decode_init,
     NULL,
     NULL,
     vmdaudio_decode_frame,

     .long_name = NULL_IF_CONFIG_SMALL("Sierra VMD audio"),

 };