yading@10: /*
yading@10:  * Wing Commander/Xan Video Decoder
yading@10:  * Copyright (C) 2003 the ffmpeg project
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Xan video decoder for Wing Commander III computer game
yading@10:  * by Mario Brito (mbrito@student.dei.uc.pt)
yading@10:  * and Mike Melanson (melanson@pcisys.net)
yading@10:  *
yading@10:  * The xan_wc3 decoder outputs PAL8 data.
yading@10:  */
yading@10: 
yading@10: #include <stdio.h>
yading@10: #include <stdlib.h>
yading@10: #include <string.h>
yading@10: 
yading@10: #include "libavutil/intreadwrite.h"
yading@10: #include "libavutil/mem.h"
yading@10: #include "avcodec.h"
yading@10: #include "bytestream.h"
yading@10: #define BITSTREAM_READER_LE
yading@10: #include "get_bits.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: #define RUNTIME_GAMMA 0
yading@10: 
yading@10: #define VGA__TAG MKTAG('V', 'G', 'A', ' ')
yading@10: #define PALT_TAG MKTAG('P', 'A', 'L', 'T')
yading@10: #define SHOT_TAG MKTAG('S', 'H', 'O', 'T')
yading@10: #define PALETTE_COUNT 256
yading@10: #define PALETTE_SIZE (PALETTE_COUNT * 3)
yading@10: #define PALETTES_MAX 256
yading@10: 
yading@10: typedef struct XanContext {
yading@10: 
yading@10:     AVCodecContext *avctx;
yading@10:     AVFrame *last_frame;
yading@10: 
yading@10:     const unsigned char *buf;
yading@10:     int size;
yading@10: 
yading@10:     /* scratch space */
yading@10:     unsigned char *buffer1;
yading@10:     int buffer1_size;
yading@10:     unsigned char *buffer2;
yading@10:     int buffer2_size;
yading@10: 
yading@10:     unsigned *palettes;
yading@10:     int palettes_count;
yading@10:     int cur_palette;
yading@10: 
yading@10:     int frame_size;
yading@10: 
yading@10: } XanContext;
yading@10: 
yading@10: static av_cold int xan_decode_end(AVCodecContext *avctx);
yading@10: 
yading@10: static av_cold int xan_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     XanContext *s = avctx->priv_data;
yading@10: 
yading@10:     s->avctx = avctx;
yading@10:     s->frame_size = 0;
yading@10: 
yading@10:     avctx->pix_fmt = AV_PIX_FMT_PAL8;
yading@10: 
yading@10:     s->buffer1_size = avctx->width * avctx->height;
yading@10:     s->buffer1 = av_malloc(s->buffer1_size);
yading@10:     if (!s->buffer1)
yading@10:         return AVERROR(ENOMEM);
yading@10:     s->buffer2_size = avctx->width * avctx->height;
yading@10:     s->buffer2 = av_malloc(s->buffer2_size + 130);
yading@10:     if (!s->buffer2) {
yading@10:         av_freep(&s->buffer1);
yading@10:         return AVERROR(ENOMEM);
yading@10:     }
yading@10:     s->last_frame = av_frame_alloc();
yading@10:     if (!s->last_frame) {
yading@10:         xan_decode_end(avctx);
yading@10:         return AVERROR(ENOMEM);
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int xan_huffman_decode(unsigned char *dest, int dest_len,
yading@10:                               const unsigned char *src, int src_len)
yading@10: {
yading@10:     unsigned char byte = *src++;
yading@10:     unsigned char ival = byte + 0x16;
yading@10:     const unsigned char * ptr = src + byte*2;
yading@10:     int ptr_len = src_len - 1 - byte*2;
yading@10:     unsigned char val = ival;
yading@10:     unsigned char *dest_end = dest + dest_len;
yading@10:     GetBitContext gb;
yading@10: 
yading@10:     if (ptr_len < 0)
yading@10:         return AVERROR_INVALIDDATA;
yading@10: 
yading@10:     init_get_bits(&gb, ptr, ptr_len * 8);
yading@10: 
yading@10:     while (val != 0x16) {
yading@10:         unsigned idx = val - 0x17 + get_bits1(&gb) * byte;
yading@10:         if (idx >= 2 * byte)
yading@10:             return AVERROR_INVALIDDATA;
yading@10:         val = src[idx];
yading@10: 
yading@10:         if (val < 0x16) {
yading@10:             if (dest >= dest_end)
yading@10:                 return 0;
yading@10:             *dest++ = val;
yading@10:             val = ival;
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * unpack simple compression
yading@10:  *
yading@10:  * @param dest destination buffer of dest_len, must be padded with at least 130 bytes
yading@10:  */
yading@10: static void xan_unpack(unsigned char *dest, int dest_len,
yading@10:                        const unsigned char *src, int src_len)
yading@10: {
yading@10:     unsigned char opcode;
yading@10:     int size;
yading@10:     unsigned char *dest_org = dest;
yading@10:     unsigned char *dest_end = dest + dest_len;
yading@10:     GetByteContext ctx;
yading@10: 
yading@10:     bytestream2_init(&ctx, src, src_len);
yading@10:     while (dest < dest_end && bytestream2_get_bytes_left(&ctx)) {
yading@10:         opcode = bytestream2_get_byte(&ctx);
yading@10: 
yading@10:         if (opcode < 0xe0) {
yading@10:             int size2, back;
yading@10:             if ((opcode & 0x80) == 0) {
yading@10:                 size = opcode & 3;
yading@10: 
yading@10:                 back  = ((opcode & 0x60) << 3) + bytestream2_get_byte(&ctx) + 1;
yading@10:                 size2 = ((opcode & 0x1c) >> 2) + 3;
yading@10:             } else if ((opcode & 0x40) == 0) {
yading@10:                 size = bytestream2_peek_byte(&ctx) >> 6;
yading@10: 
yading@10:                 back  = (bytestream2_get_be16(&ctx) & 0x3fff) + 1;
yading@10:                 size2 = (opcode & 0x3f) + 4;
yading@10:             } else {
yading@10:                 size = opcode & 3;
yading@10: 
yading@10:                 back  = ((opcode & 0x10) << 12) + bytestream2_get_be16(&ctx) + 1;
yading@10:                 size2 = ((opcode & 0x0c) <<  6) + bytestream2_get_byte(&ctx) + 5;
yading@10:             }
yading@10: 
yading@10:             if (dest_end - dest < size + size2 ||
yading@10:                 dest + size - dest_org < back ||
yading@10:                 bytestream2_get_bytes_left(&ctx) < size)
yading@10:                 return;
yading@10:             bytestream2_get_buffer(&ctx, dest, size);
yading@10:             dest += size;
yading@10:             av_memcpy_backptr(dest, back, size2);
yading@10:             dest += size2;
yading@10:         } else {
yading@10:             int finish = opcode >= 0xfc;
yading@10:             size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4;
yading@10: 
yading@10:             if (dest_end - dest < size || bytestream2_get_bytes_left(&ctx) < size)
yading@10:                 return;
yading@10:             bytestream2_get_buffer(&ctx, dest, size);
yading@10:             dest += size;
yading@10:             if (finish)
yading@10:                 return;
yading@10:         }
yading@10:     }
yading@10: }
yading@10: 
yading@10: static inline void xan_wc3_output_pixel_run(XanContext *s, AVFrame *frame,
yading@10:     const unsigned char *pixel_buffer, int x, int y, int pixel_count)
yading@10: {
yading@10:     int stride;
yading@10:     int line_inc;
yading@10:     int index;
yading@10:     int current_x;
yading@10:     int width = s->avctx->width;
yading@10:     unsigned char *palette_plane;
yading@10: 
yading@10:     palette_plane = frame->data[0];
yading@10:     stride = frame->linesize[0];
yading@10:     line_inc = stride - width;
yading@10:     index = y * stride + x;
yading@10:     current_x = x;
yading@10:     while (pixel_count && index < s->frame_size) {
yading@10:         int count = FFMIN(pixel_count, width - current_x);
yading@10:         memcpy(palette_plane + index, pixel_buffer, count);
yading@10:         pixel_count  -= count;
yading@10:         index        += count;
yading@10:         pixel_buffer += count;
yading@10:         current_x    += count;
yading@10: 
yading@10:         if (current_x >= width) {
yading@10:             index += line_inc;
yading@10:             current_x = 0;
yading@10:         }
yading@10:     }
yading@10: }
yading@10: 
yading@10: static inline void xan_wc3_copy_pixel_run(XanContext *s, AVFrame *frame,
yading@10:                                           int x, int y,
yading@10:                                           int pixel_count, int motion_x,
yading@10:                                           int motion_y)
yading@10: {
yading@10:     int stride;
yading@10:     int line_inc;
yading@10:     int curframe_index, prevframe_index;
yading@10:     int curframe_x, prevframe_x;
yading@10:     int width = s->avctx->width;
yading@10:     unsigned char *palette_plane, *prev_palette_plane;
yading@10: 
yading@10:     if (y + motion_y < 0 || y + motion_y >= s->avctx->height ||
yading@10:         x + motion_x < 0 || x + motion_x >= s->avctx->width)
yading@10:         return;
yading@10: 
yading@10:     palette_plane = frame->data[0];
yading@10:     prev_palette_plane = s->last_frame->data[0];
yading@10:     if (!prev_palette_plane)
yading@10:         prev_palette_plane = palette_plane;
yading@10:     stride = frame->linesize[0];
yading@10:     line_inc = stride - width;
yading@10:     curframe_index = y * stride + x;
yading@10:     curframe_x = x;
yading@10:     prevframe_index = (y + motion_y) * stride + x + motion_x;
yading@10:     prevframe_x = x + motion_x;
yading@10: 
yading@10:     if (prev_palette_plane == palette_plane && FFABS(curframe_index - prevframe_index) < pixel_count) {
yading@10:          avpriv_request_sample(s->avctx, "Overlapping copy\n");
yading@10:          return ;
yading@10:     }
yading@10: 
yading@10:     while (pixel_count &&
yading@10:            curframe_index  < s->frame_size &&
yading@10:            prevframe_index < s->frame_size) {
yading@10:         int count = FFMIN3(pixel_count, width - curframe_x,
yading@10:                            width - prevframe_x);
yading@10: 
yading@10:         memcpy(palette_plane + curframe_index,
yading@10:                prev_palette_plane + prevframe_index, count);
yading@10:         pixel_count     -= count;
yading@10:         curframe_index  += count;
yading@10:         prevframe_index += count;
yading@10:         curframe_x      += count;
yading@10:         prevframe_x     += count;
yading@10: 
yading@10:         if (curframe_x >= width) {
yading@10:             curframe_index += line_inc;
yading@10:             curframe_x = 0;
yading@10:         }
yading@10: 
yading@10:         if (prevframe_x >= width) {
yading@10:             prevframe_index += line_inc;
yading@10:             prevframe_x = 0;
yading@10:         }
yading@10:     }
yading@10: }
yading@10: 
yading@10: static int xan_wc3_decode_frame(XanContext *s, AVFrame *frame)
yading@10: {
yading@10: 
yading@10:     int width  = s->avctx->width;
yading@10:     int height = s->avctx->height;
yading@10:     int total_pixels = width * height;
yading@10:     unsigned char opcode;
yading@10:     unsigned char flag = 0;
yading@10:     int size = 0;
yading@10:     int motion_x, motion_y;
yading@10:     int x, y;
yading@10: 
yading@10:     unsigned char *opcode_buffer = s->buffer1;
yading@10:     unsigned char *opcode_buffer_end = s->buffer1 + s->buffer1_size;
yading@10:     int opcode_buffer_size = s->buffer1_size;
yading@10:     const unsigned char *imagedata_buffer = s->buffer2;
yading@10: 
yading@10:     /* pointers to segments inside the compressed chunk */
yading@10:     const unsigned char *huffman_segment;
yading@10:     const unsigned char *size_segment;
yading@10:     const unsigned char *vector_segment;
yading@10:     const unsigned char *imagedata_segment;
yading@10:     const unsigned char *buf_end = s->buf + s->size;
yading@10:     int huffman_offset, size_offset, vector_offset, imagedata_offset,
yading@10:         imagedata_size;
yading@10: 
yading@10:     if (s->size < 8)
yading@10:         return AVERROR_INVALIDDATA;
yading@10: 
yading@10:     huffman_offset    = AV_RL16(&s->buf[0]);
yading@10:     size_offset       = AV_RL16(&s->buf[2]);
yading@10:     vector_offset     = AV_RL16(&s->buf[4]);
yading@10:     imagedata_offset  = AV_RL16(&s->buf[6]);
yading@10: 
yading@10:     if (huffman_offset   >= s->size ||
yading@10:         size_offset      >= s->size ||
yading@10:         vector_offset    >= s->size ||
yading@10:         imagedata_offset >= s->size)
yading@10:         return AVERROR_INVALIDDATA;
yading@10: 
yading@10:     huffman_segment   = s->buf + huffman_offset;
yading@10:     size_segment      = s->buf + size_offset;
yading@10:     vector_segment    = s->buf + vector_offset;
yading@10:     imagedata_segment = s->buf + imagedata_offset;
yading@10: 
yading@10:     if (xan_huffman_decode(opcode_buffer, opcode_buffer_size,
yading@10:                            huffman_segment, s->size - huffman_offset) < 0)
yading@10:         return AVERROR_INVALIDDATA;
yading@10: 
yading@10:     if (imagedata_segment[0] == 2) {
yading@10:         xan_unpack(s->buffer2, s->buffer2_size,
yading@10:                    &imagedata_segment[1], s->size - imagedata_offset - 1);
yading@10:         imagedata_size = s->buffer2_size;
yading@10:     } else {
yading@10:         imagedata_size = s->size - imagedata_offset - 1;
yading@10:         imagedata_buffer = &imagedata_segment[1];
yading@10:     }
yading@10: 
yading@10:     /* use the decoded data segments to build the frame */
yading@10:     x = y = 0;
yading@10:     while (total_pixels && opcode_buffer < opcode_buffer_end) {
yading@10: 
yading@10:         opcode = *opcode_buffer++;
yading@10:         size = 0;
yading@10: 
yading@10:         switch (opcode) {
yading@10: 
yading@10:         case 0:
yading@10:             flag ^= 1;
yading@10:             continue;
yading@10: 
yading@10:         case 1:
yading@10:         case 2:
yading@10:         case 3:
yading@10:         case 4:
yading@10:         case 5:
yading@10:         case 6:
yading@10:         case 7:
yading@10:         case 8:
yading@10:             size = opcode;
yading@10:             break;
yading@10: 
yading@10:         case 12:
yading@10:         case 13:
yading@10:         case 14:
yading@10:         case 15:
yading@10:         case 16:
yading@10:         case 17:
yading@10:         case 18:
yading@10:             size += (opcode - 10);
yading@10:             break;
yading@10: 
yading@10:         case 9:
yading@10:         case 19:
yading@10:             if (buf_end - size_segment < 1) {
yading@10:                 av_log(s->avctx, AV_LOG_ERROR, "size_segment overread\n");
yading@10:                 return AVERROR_INVALIDDATA;
yading@10:             }
yading@10:             size = *size_segment++;
yading@10:             break;
yading@10: 
yading@10:         case 10:
yading@10:         case 20:
yading@10:             if (buf_end - size_segment < 2) {
yading@10:                 av_log(s->avctx, AV_LOG_ERROR, "size_segment overread\n");
yading@10:                 return AVERROR_INVALIDDATA;
yading@10:             }
yading@10:             size = AV_RB16(&size_segment[0]);
yading@10:             size_segment += 2;
yading@10:             break;
yading@10: 
yading@10:         case 11:
yading@10:         case 21:
yading@10:             if (buf_end - size_segment < 3) {
yading@10:                 av_log(s->avctx, AV_LOG_ERROR, "size_segment overread\n");
yading@10:                 return AVERROR_INVALIDDATA;
yading@10:             }
yading@10:             size = AV_RB24(size_segment);
yading@10:             size_segment += 3;
yading@10:             break;
yading@10:         }
yading@10: 
yading@10:         if (size > total_pixels)
yading@10:             break;
yading@10: 
yading@10:         if (opcode < 12) {
yading@10:             flag ^= 1;
yading@10:             if (flag) {
yading@10:                 /* run of (size) pixels is unchanged from last frame */
yading@10:                 xan_wc3_copy_pixel_run(s, frame, x, y, size, 0, 0);
yading@10:             } else {
yading@10:                 /* output a run of pixels from imagedata_buffer */
yading@10:                 if (imagedata_size < size)
yading@10:                     break;
yading@10:                 xan_wc3_output_pixel_run(s, frame, imagedata_buffer, x, y, size);
yading@10:                 imagedata_buffer += size;
yading@10:                 imagedata_size -= size;
yading@10:             }
yading@10:         } else {
yading@10:             if (vector_segment >= buf_end) {
yading@10:                 av_log(s->avctx, AV_LOG_ERROR, "vector_segment overread\n");
yading@10:                 return AVERROR_INVALIDDATA;
yading@10:             }
yading@10:             /* run-based motion compensation from last frame */
yading@10:             motion_x = sign_extend(*vector_segment >> 4,  4);
yading@10:             motion_y = sign_extend(*vector_segment & 0xF, 4);
yading@10:             vector_segment++;
yading@10: 
yading@10:             /* copy a run of pixels from the previous frame */
yading@10:             xan_wc3_copy_pixel_run(s, frame, x, y, size, motion_x, motion_y);
yading@10: 
yading@10:             flag = 0;
yading@10:         }
yading@10: 
yading@10:         /* coordinate accounting */
yading@10:         total_pixels -= size;
yading@10:         y += (x + size) / width;
yading@10:         x  = (x + size) % width;
yading@10:     }
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: #if RUNTIME_GAMMA
yading@10: static inline unsigned mul(unsigned a, unsigned b)
yading@10: {
yading@10:     return (a * b) >> 16;
yading@10: }
yading@10: 
yading@10: static inline unsigned pow4(unsigned a)
yading@10: {
yading@10:     unsigned square = mul(a, a);
yading@10:     return mul(square, square);
yading@10: }
yading@10: 
yading@10: static inline unsigned pow5(unsigned a)
yading@10: {
yading@10:     return mul(pow4(a), a);
yading@10: }
yading@10: 
yading@10: static uint8_t gamma_corr(uint8_t in) {
yading@10:     unsigned lo, hi = 0xff40, target;
yading@10:     int i = 15;
yading@10:     in = (in << 2) | (in >> 6);
yading@10:     /*  equivalent float code:
yading@10:     if (in >= 252)
yading@10:         return 253;
yading@10:     return round(pow(in / 256.0, 0.8) * 256);
yading@10:     */
yading@10:     lo = target = in << 8;
yading@10:     do {
yading@10:         unsigned mid = (lo + hi) >> 1;
yading@10:         unsigned pow = pow5(mid);
yading@10:         if (pow > target) hi = mid;
yading@10:         else lo = mid;
yading@10:     } while (--i);
yading@10:     return (pow4((lo + hi) >> 1) + 0x80) >> 8;
yading@10: }
yading@10: #else
yading@10: /**
yading@10:  * This is a gamma correction that xan3 applies to all palette entries.
yading@10:  *
yading@10:  * There is a peculiarity, namely that the values are clamped to 253 -
yading@10:  * it seems likely that this table was calculated by a buggy fixed-point
yading@10:  * implementation, the one above under RUNTIME_GAMMA behaves like this for
yading@10:  * example.
yading@10:  * The exponent value of 0.8 can be explained by this as well, since 0.8 = 4/5
yading@10:  * and thus pow(x, 0.8) is still easy to calculate.
yading@10:  * Also, the input values are first rotated to the left by 2.
yading@10:  */
yading@10: static const uint8_t gamma_lookup[256] = {
yading@10:     0x00, 0x09, 0x10, 0x16, 0x1C, 0x21, 0x27, 0x2C,
yading@10:     0x31, 0x35, 0x3A, 0x3F, 0x43, 0x48, 0x4C, 0x50,
yading@10:     0x54, 0x59, 0x5D, 0x61, 0x65, 0x69, 0x6D, 0x71,
yading@10:     0x75, 0x79, 0x7D, 0x80, 0x84, 0x88, 0x8C, 0x8F,
yading@10:     0x93, 0x97, 0x9A, 0x9E, 0xA2, 0xA5, 0xA9, 0xAC,
yading@10:     0xB0, 0xB3, 0xB7, 0xBA, 0xBE, 0xC1, 0xC5, 0xC8,
yading@10:     0xCB, 0xCF, 0xD2, 0xD5, 0xD9, 0xDC, 0xDF, 0xE3,
yading@10:     0xE6, 0xE9, 0xED, 0xF0, 0xF3, 0xF6, 0xFA, 0xFD,
yading@10:     0x03, 0x0B, 0x12, 0x18, 0x1D, 0x23, 0x28, 0x2D,
yading@10:     0x32, 0x36, 0x3B, 0x40, 0x44, 0x49, 0x4D, 0x51,
yading@10:     0x56, 0x5A, 0x5E, 0x62, 0x66, 0x6A, 0x6E, 0x72,
yading@10:     0x76, 0x7A, 0x7D, 0x81, 0x85, 0x89, 0x8D, 0x90,
yading@10:     0x94, 0x98, 0x9B, 0x9F, 0xA2, 0xA6, 0xAA, 0xAD,
yading@10:     0xB1, 0xB4, 0xB8, 0xBB, 0xBF, 0xC2, 0xC5, 0xC9,
yading@10:     0xCC, 0xD0, 0xD3, 0xD6, 0xDA, 0xDD, 0xE0, 0xE4,
yading@10:     0xE7, 0xEA, 0xED, 0xF1, 0xF4, 0xF7, 0xFA, 0xFD,
yading@10:     0x05, 0x0D, 0x13, 0x19, 0x1F, 0x24, 0x29, 0x2E,
yading@10:     0x33, 0x38, 0x3C, 0x41, 0x45, 0x4A, 0x4E, 0x52,
yading@10:     0x57, 0x5B, 0x5F, 0x63, 0x67, 0x6B, 0x6F, 0x73,
yading@10:     0x77, 0x7B, 0x7E, 0x82, 0x86, 0x8A, 0x8D, 0x91,
yading@10:     0x95, 0x99, 0x9C, 0xA0, 0xA3, 0xA7, 0xAA, 0xAE,
yading@10:     0xB2, 0xB5, 0xB9, 0xBC, 0xBF, 0xC3, 0xC6, 0xCA,
yading@10:     0xCD, 0xD0, 0xD4, 0xD7, 0xDA, 0xDE, 0xE1, 0xE4,
yading@10:     0xE8, 0xEB, 0xEE, 0xF1, 0xF5, 0xF8, 0xFB, 0xFD,
yading@10:     0x07, 0x0E, 0x15, 0x1A, 0x20, 0x25, 0x2A, 0x2F,
yading@10:     0x34, 0x39, 0x3D, 0x42, 0x46, 0x4B, 0x4F, 0x53,
yading@10:     0x58, 0x5C, 0x60, 0x64, 0x68, 0x6C, 0x70, 0x74,
yading@10:     0x78, 0x7C, 0x7F, 0x83, 0x87, 0x8B, 0x8E, 0x92,
yading@10:     0x96, 0x99, 0x9D, 0xA1, 0xA4, 0xA8, 0xAB, 0xAF,
yading@10:     0xB2, 0xB6, 0xB9, 0xBD, 0xC0, 0xC4, 0xC7, 0xCB,
yading@10:     0xCE, 0xD1, 0xD5, 0xD8, 0xDB, 0xDF, 0xE2, 0xE5,
yading@10:     0xE9, 0xEC, 0xEF, 0xF2, 0xF6, 0xF9, 0xFC, 0xFD
yading@10: };
yading@10: #endif
yading@10: 
yading@10: static int xan_decode_frame(AVCodecContext *avctx,
yading@10:                             void *data, int *got_frame,
yading@10:                             AVPacket *avpkt)
yading@10: {
yading@10:     AVFrame *frame = data;
yading@10:     const uint8_t *buf = avpkt->data;
yading@10:     int ret, buf_size = avpkt->size;
yading@10:     XanContext *s = avctx->priv_data;
yading@10:     GetByteContext ctx;
yading@10:     int tag = 0;
yading@10: 
yading@10:     bytestream2_init(&ctx, buf, buf_size);
yading@10:     while (bytestream2_get_bytes_left(&ctx) > 8 && tag != VGA__TAG) {
yading@10:         unsigned *tmpptr;
yading@10:         uint32_t new_pal;
yading@10:         int size;
yading@10:         int i;
yading@10:         tag  = bytestream2_get_le32(&ctx);
yading@10:         size = bytestream2_get_be32(&ctx);
yading@10:         if(size < 0) {
yading@10:             av_log(avctx, AV_LOG_ERROR, "Invalid tag size %d\n", size);
yading@10:             return AVERROR_INVALIDDATA;
yading@10:         }
yading@10:         size = FFMIN(size, bytestream2_get_bytes_left(&ctx));
yading@10:         switch (tag) {
yading@10:         case PALT_TAG:
yading@10:             if (size < PALETTE_SIZE)
yading@10:                 return AVERROR_INVALIDDATA;
yading@10:             if (s->palettes_count >= PALETTES_MAX)
yading@10:                 return AVERROR_INVALIDDATA;
yading@10:             tmpptr = av_realloc(s->palettes,
yading@10:                                 (s->palettes_count + 1) * AVPALETTE_SIZE);
yading@10:             if (!tmpptr)
yading@10:                 return AVERROR(ENOMEM);
yading@10:             s->palettes = tmpptr;
yading@10:             tmpptr += s->palettes_count * AVPALETTE_COUNT;
yading@10:             for (i = 0; i < PALETTE_COUNT; i++) {
yading@10: #if RUNTIME_GAMMA
yading@10:                 int r = gamma_corr(bytestream2_get_byteu(&ctx));
yading@10:                 int g = gamma_corr(bytestream2_get_byteu(&ctx));
yading@10:                 int b = gamma_corr(bytestream2_get_byteu(&ctx));
yading@10: #else
yading@10:                 int r = gamma_lookup[bytestream2_get_byteu(&ctx)];
yading@10:                 int g = gamma_lookup[bytestream2_get_byteu(&ctx)];
yading@10:                 int b = gamma_lookup[bytestream2_get_byteu(&ctx)];
yading@10: #endif
yading@10:                 *tmpptr++ = (0xFFU << 24) | (r << 16) | (g << 8) | b;
yading@10:             }
yading@10:             s->palettes_count++;
yading@10:             break;
yading@10:         case SHOT_TAG:
yading@10:             if (size < 4)
yading@10:                 return AVERROR_INVALIDDATA;
yading@10:             new_pal = bytestream2_get_le32(&ctx);
yading@10:             if (new_pal < s->palettes_count) {
yading@10:                 s->cur_palette = new_pal;
yading@10:             } else
yading@10:                 av_log(avctx, AV_LOG_ERROR, "Invalid palette selected\n");
yading@10:             break;
yading@10:         case VGA__TAG:
yading@10:             break;
yading@10:         default:
yading@10:             bytestream2_skip(&ctx, size);
yading@10:             break;
yading@10:         }
yading@10:     }
yading@10:     buf_size = bytestream2_get_bytes_left(&ctx);
yading@10: 
yading@10:     if (s->palettes_count <= 0) {
yading@10:         av_log(s->avctx, AV_LOG_ERROR, "No palette found\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     if (!s->frame_size)
yading@10:         s->frame_size = frame->linesize[0] * s->avctx->height;
yading@10: 
yading@10:     memcpy(frame->data[1],
yading@10:            s->palettes + s->cur_palette * AVPALETTE_COUNT, AVPALETTE_SIZE);
yading@10: 
yading@10:     s->buf = ctx.buffer;
yading@10:     s->size = buf_size;
yading@10: 
yading@10:     if (xan_wc3_decode_frame(s, frame) < 0)
yading@10:         return AVERROR_INVALIDDATA;
yading@10: 
yading@10:     av_frame_unref(s->last_frame);
yading@10:     if ((ret = av_frame_ref(s->last_frame, frame)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     *got_frame = 1;
yading@10: 
yading@10:     /* always report that the buffer was completely consumed */
yading@10:     return buf_size;
yading@10: }
yading@10: 
yading@10: static av_cold int xan_decode_end(AVCodecContext *avctx)
yading@10: {
yading@10:     XanContext *s = avctx->priv_data;
yading@10: 
yading@10:     av_frame_free(&s->last_frame);
yading@10: 
yading@10:     av_freep(&s->buffer1);
yading@10:     av_freep(&s->buffer2);
yading@10:     av_freep(&s->palettes);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: AVCodec ff_xan_wc3_decoder = {
yading@10:     .name           = "xan_wc3",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_XAN_WC3,
yading@10:     .priv_data_size = sizeof(XanContext),
yading@10:     .init           = xan_decode_init,
yading@10:     .close          = xan_decode_end,
yading@10:     .decode         = xan_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("Wing Commander III / Xan"),
yading@10: };