* 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 xan.c
+ * @file libavcodec/xan.c
* Xan video decoder for Wing Commander III computer game
* by Mario Brito (mbrito@student.dei.uc.pt)
* and Mike Melanson (melanson@pcisys.net)
#include <string.h>
#include <unistd.h>
-#include "common.h"
+#include "libavutil/intreadwrite.h"
#include "avcodec.h"
+#include "bytestream.h"
+#define ALT_BITSTREAM_READER_LE
+#include "get_bits.h"
+// for av_memcpy_backptr
+#include "libavutil/lzo.h"
typedef struct XanContext {
AVFrame last_frame;
AVFrame current_frame;
- unsigned char *buf;
+ const unsigned char *buf;
int size;
/* scratch space */
} XanContext;
-static int xan_decode_init(AVCodecContext *avctx)
+static av_cold int xan_decode_init(AVCodecContext *avctx)
{
XanContext *s = avctx->priv_data;
}
avctx->pix_fmt = PIX_FMT_PAL8;
- avctx->has_b_frames = 0;
if(avcodec_check_dimensions(avctx, avctx->width, avctx->height))
return -1;
s->buffer1_size = avctx->width * avctx->height;
s->buffer1 = av_malloc(s->buffer1_size);
s->buffer2_size = avctx->width * avctx->height;
- s->buffer2 = av_malloc(s->buffer2_size);
+ s->buffer2 = av_malloc(s->buffer2_size + 130);
if (!s->buffer1 || !s->buffer2)
return -1;
return 0;
}
-/* This function is used in lieu of memcpy(). This decoder can not use
- * memcpy because the memory locations often overlap and
- * memcpy doesn't like that; it's not uncommon, for example, for
- * dest = src+1, to turn byte A into pattern AAAAAAAA.
- * This was originally repz movsb in Intel x86 ASM. */
-static inline void bytecopy(unsigned char *dest, unsigned char *src, int count)
-{
- int i;
-
- for (i = 0; i < count; i++)
- dest[i] = src[i];
-}
-
-static int xan_huffman_decode(unsigned char *dest, unsigned char *src,
+static int xan_huffman_decode(unsigned char *dest, const unsigned char *src,
int dest_len)
{
unsigned char byte = *src++;
unsigned char ival = byte + 0x16;
- unsigned char * ptr = src + byte*2;
+ const unsigned char * ptr = src + byte*2;
unsigned char val = ival;
- int counter = 0;
unsigned char *dest_end = dest + dest_len;
+ GetBitContext gb;
- unsigned char bits = *ptr++;
+ init_get_bits(&gb, ptr, 0); // FIXME: no src size available
while ( val != 0x16 ) {
- if ( (1 << counter) & bits )
- val = src[byte + val - 0x17];
- else
- val = src[val - 0x17];
+ val = src[val - 0x17 + get_bits1(&gb) * byte];
if ( val < 0x16 ) {
- if (dest + 1 > dest_end)
+ if (dest >= dest_end)
return 0;
*dest++ = val;
val = ival;
}
-
- if (counter++ == 7) {
- counter = 0;
- bits = *ptr++;
- }
}
return 0;
}
-static void xan_unpack(unsigned char *dest, unsigned char *src, int dest_len)
+/**
+ * unpack simple compression
+ *
+ * @param dest destination buffer of dest_len, must be padded with at least 130 bytes
+ */
+static void xan_unpack(unsigned char *dest, const unsigned char *src, int dest_len)
{
unsigned char opcode;
int size;
- int offset;
- int byte1, byte2, byte3;
unsigned char *dest_end = dest + dest_len;
- for (;;) {
+ while (dest < dest_end) {
opcode = *src++;
- if ( (opcode & 0x80) == 0 ) {
-
- offset = *src++;
-
- size = opcode & 3;
- if (dest + size > dest_end)
- return;
- bytecopy(dest, src, size); dest += size; src += size;
-
- size = ((opcode & 0x1c) >> 2) + 3;
- if (dest + size > dest_end)
- return;
- bytecopy (dest, dest - (((opcode & 0x60) << 3) + offset + 1), size);
- dest += size;
+ if (opcode < 0xe0) {
+ int size2, back;
+ if ( (opcode & 0x80) == 0 ) {
- } else if ( (opcode & 0x40) == 0 ) {
+ size = opcode & 3;
- byte1 = *src++;
- byte2 = *src++;
+ back = ((opcode & 0x60) << 3) + *src++ + 1;
+ size2 = ((opcode & 0x1c) >> 2) + 3;
- size = byte1 >> 6;
- if (dest + size > dest_end)
- return;
- bytecopy (dest, src, size); dest += size; src += size;
+ } else if ( (opcode & 0x40) == 0 ) {
- size = (opcode & 0x3f) + 4;
- if (dest + size > dest_end)
- return;
- bytecopy (dest, dest - (((byte1 & 0x3f) << 8) + byte2 + 1), size);
- dest += size;
+ size = *src >> 6;
- } else if ( (opcode & 0x20) == 0 ) {
+ back = (bytestream_get_be16(&src) & 0x3fff) + 1;
+ size2 = (opcode & 0x3f) + 4;
- byte1 = *src++;
- byte2 = *src++;
- byte3 = *src++;
+ } else {
- size = opcode & 3;
- if (dest + size > dest_end)
- return;
- bytecopy (dest, src, size); dest += size; src += size;
+ size = opcode & 3;
- size = byte3 + 5 + ((opcode & 0xc) << 6);
- if (dest + size > dest_end)
- return;
- bytecopy (dest,
- dest - ((((opcode & 0x10) >> 4) << 0x10) + 1 + (byte1 << 8) + byte2),
- size);
- dest += size;
+ back = ((opcode & 0x10) << 12) + bytestream_get_be16(&src) + 1;
+ size2 = ((opcode & 0x0c) << 6) + *src++ + 5;
+ if (size + size2 > dest_end - dest)
+ return;
+ }
+ memcpy(dest, src, size); dest += size; src += size;
+ av_memcpy_backptr(dest, back, size2);
+ dest += size2;
} else {
+ int finish;
size = ((opcode & 0x1f) << 2) + 4;
- if (size > 0x70)
- break;
+ finish = size > 0x70;
+ if (finish)
+ size = opcode & 3;
- if (dest + size > dest_end)
+ memcpy(dest, src, size); dest += size; src += size;
+ if (finish)
return;
- bytecopy (dest, src, size); dest += size; src += size;
}
}
-
- size = opcode & 3;
- bytecopy(dest, src, size); dest += size; src += size;
}
-static void inline xan_wc3_output_pixel_run(XanContext *s,
- unsigned char *pixel_buffer, int x, int y, int pixel_count)
+static inline void xan_wc3_output_pixel_run(XanContext *s,
+ const unsigned char *pixel_buffer, int x, int y, int pixel_count)
{
int stride;
int line_inc;
}
}
-static void inline xan_wc3_copy_pixel_run(XanContext *s,
+static inline void xan_wc3_copy_pixel_run(XanContext *s,
int x, int y, int pixel_count, int motion_x, int motion_y)
{
int stride;
unsigned char *opcode_buffer = s->buffer1;
int opcode_buffer_size = s->buffer1_size;
- unsigned char *imagedata_buffer = s->buffer2;
- int imagedata_buffer_size = s->buffer2_size;
+ const unsigned char *imagedata_buffer = s->buffer2;
/* pointers to segments inside the compressed chunk */
- unsigned char *huffman_segment;
- unsigned char *size_segment;
- unsigned char *vector_segment;
- unsigned char *imagedata_segment;
+ const unsigned char *huffman_segment;
+ const unsigned char *size_segment;
+ const unsigned char *vector_segment;
+ const unsigned char *imagedata_segment;
huffman_segment = s->buf + AV_RL16(&s->buf[0]);
size_segment = s->buf + AV_RL16(&s->buf[2]);
xan_huffman_decode(opcode_buffer, huffman_segment, opcode_buffer_size);
if (imagedata_segment[0] == 2)
- xan_unpack(imagedata_buffer, &imagedata_segment[1],
- imagedata_buffer_size);
+ xan_unpack(s->buffer2, &imagedata_segment[1], s->buffer2_size);
else
imagedata_buffer = &imagedata_segment[1];
case 11:
case 21:
- size = (size_segment[0] << 16) | (size_segment[1] << 8) |
- size_segment[2];
+ size = AV_RB24(size_segment);
size_segment += 3;
break;
}
}
} else {
/* run-based motion compensation from last frame */
- motion_x = (*vector_segment >> 4) & 0xF;
- motion_y = *vector_segment & 0xF;
+ motion_x = sign_extend(*vector_segment >> 4, 4);
+ motion_y = sign_extend(*vector_segment & 0xF, 4);
vector_segment++;
- /* sign extension */
- if (motion_x & 0x8)
- motion_x |= 0xFFFFFFF0;
- if (motion_y & 0x8)
- motion_y |= 0xFFFFFFF0;
-
/* copy a run of pixels from the previous frame */
xan_wc3_copy_pixel_run(s, x, y, size, motion_x, motion_y);
/* coordinate accounting */
total_pixels -= size;
- while (size) {
- if (x + size >= width) {
- y++;
- size -= (width - x);
- x = 0;
- } else {
- x += size;
- size = 0;
- }
- }
+ y += (x + size) / width;
+ x = (x + size) % width;
}
}
static int xan_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
- uint8_t *buf, int buf_size)
+ AVPacket *avpkt)
{
+ const uint8_t *buf = avpkt->data;
+ int buf_size = avpkt->size;
XanContext *s = avctx->priv_data;
AVPaletteControl *palette_control = avctx->palctrl;
if (s->last_frame.data[0])
avctx->release_buffer(avctx, &s->last_frame);
- /* shuffle frames */
- s->last_frame = s->current_frame;
-
*data_size = sizeof(AVFrame);
*(AVFrame*)data = s->current_frame;
+ /* shuffle frames */
+ FFSWAP(AVFrame, s->current_frame, s->last_frame);
+
/* always report that the buffer was completely consumed */
return buf_size;
}
-static int xan_decode_end(AVCodecContext *avctx)
+static av_cold int xan_decode_end(AVCodecContext *avctx)
{
XanContext *s = avctx->priv_data;
- /* release the last frame */
+ /* release the frames */
if (s->last_frame.data[0])
avctx->release_buffer(avctx, &s->last_frame);
+ if (s->current_frame.data[0])
+ avctx->release_buffer(avctx, &s->current_frame);
av_free(s->buffer1);
av_free(s->buffer2);
xan_decode_end,
xan_decode_frame,
CODEC_CAP_DR1,
+ .long_name = NULL_IF_CONFIG_SMALL("Wing Commander III / Xan"),
};
/*
projects / frescor / ffmpeg.git / blobdiff