X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fxan.c;h=fcfd9c6d0c12c67feed2c0472fa305a9a30fcc3a;hb=94f28061f572b5946275cd29be0683c22cd58a18;hp=5c99e9848d9e586f43ee9ec3846037b000d3444f;hpb=4b96f43fe169bb29a9b45cbb116cd8a81cebfebe;p=ffmpeg diff --git a/libavcodec/xan.c b/libavcodec/xan.c index 5c99e9848d9..fcfd9c6d0c1 100644 --- a/libavcodec/xan.c +++ b/libavcodec/xan.c @@ -31,10 +31,12 @@ #include #include #include -#include #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" @@ -72,13 +74,10 @@ static av_cold int xan_decode_init(AVCodecContext *avctx) avctx->pix_fmt = PIX_FMT_PAL8; - 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 + 12); + s->buffer2 = av_malloc(s->buffer2_size + 130); if (!s->buffer1 || !s->buffer2) return -1; @@ -92,28 +91,20 @@ static int xan_huffman_decode(unsigned char *dest, const unsigned char *src, unsigned char ival = byte + 0x16; 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; @@ -122,82 +113,54 @@ static int xan_huffman_decode(unsigned char *dest, const unsigned char *src, /** * unpack simple compression * - * @param dest destination buffer of dest_len, must be sufficiently padded for av_memcpy_backptr + * @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 ) { + if (opcode < 0xe0) { + int size2, back; + if ( (opcode & 0x80) == 0 ) { - offset = *src++; + size = opcode & 3; - size = opcode & 3; - if (size > dest_end - dest) - return; - memcpy(dest, src, size); dest += size; src += size; + back = ((opcode & 0x60) << 3) + *src++ + 1; + size2 = ((opcode & 0x1c) >> 2) + 3; - size = ((opcode & 0x1c) >> 2) + 3; - if (size > dest_end - dest) - return; - av_memcpy_backptr(dest, ((opcode & 0x60) << 3) + offset + 1, size); - dest += size; + } else if ( (opcode & 0x40) == 0 ) { - } else if ( (opcode & 0x40) == 0 ) { + size = *src >> 6; - byte1 = *src++; - byte2 = *src++; + back = (bytestream_get_be16(&src) & 0x3fff) + 1; + size2 = (opcode & 0x3f) + 4; - size = byte1 >> 6; - if (size > dest_end - dest) - return; - memcpy(dest, src, size); dest += size; src += size; - - size = (opcode & 0x3f) + 4; - if (size > dest_end - dest) - return; - av_memcpy_backptr(dest, ((byte1 & 0x3f) << 8) + byte2 + 1, size); - dest += size; - - } else if ( (opcode & 0x20) == 0 ) { + } else { - byte1 = *src++; - byte2 = *src++; - byte3 = *src++; + size = opcode & 3; - size = opcode & 3; - if (size > dest_end - dest) - return; + 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; - - size = byte3 + 5 + ((opcode & 0xc) << 6); - if (size > dest_end - dest) - return; - av_memcpy_backptr(dest, - ((opcode & 0x10) << 12) + 1 + (byte1 << 8) + byte2, - size); - dest += size; + av_memcpy_backptr(dest, back, size2); + dest += size2; } else { - size = ((opcode & 0x1f) << 2) + 4; + int finish = opcode >= 0xfc; + size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4; - if (size > 0x70) - break; - - if (size > dest_end - dest) - return; memcpy(dest, src, size); dest += size; src += size; + if (finish) + return; } } - - size = opcode & 3; - memcpy(dest, src, size); dest += size; src += size; } static inline void xan_wc3_output_pixel_run(XanContext *s, @@ -215,13 +178,14 @@ static inline void xan_wc3_output_pixel_run(XanContext *s, line_inc = stride - width; index = y * stride + x; current_x = x; - while((pixel_count--) && (index < s->frame_size)) { - - /* don't do a memcpy() here; keyframes generally copy an entire - * frame of data and the stride needs to be accounted for */ - palette_plane[index++] = *pixel_buffer++; + while(pixel_count && (index < s->frame_size)) { + int count = FFMIN(pixel_count, width - current_x); + memcpy(palette_plane + index, pixel_buffer, count); + pixel_count -= count; + index += count; + pixel_buffer += count; + current_x += count; - current_x++; if (current_x >= width) { index += line_inc; current_x = 0; @@ -247,18 +211,21 @@ static inline void xan_wc3_copy_pixel_run(XanContext *s, curframe_x = x; prevframe_index = (y + motion_y) * stride + x + motion_x; prevframe_x = x + motion_x; - while((pixel_count--) && (curframe_index < s->frame_size)) { + while(pixel_count && (curframe_index < s->frame_size)) { + int count = FFMIN3(pixel_count, width - curframe_x, width - prevframe_x); - palette_plane[curframe_index++] = - prev_palette_plane[prevframe_index++]; + memcpy(palette_plane + curframe_index, prev_palette_plane + prevframe_index, count); + pixel_count -= count; + curframe_index += count; + prevframe_index += count; + curframe_x += count; + prevframe_x += count; - curframe_x++; if (curframe_x >= width) { curframe_index += line_inc; curframe_x = 0; } - prevframe_x++; if (prevframe_x >= width) { prevframe_index += line_inc; prevframe_x = 0; @@ -363,16 +330,10 @@ static void xan_wc3_decode_frame(XanContext *s) { } } 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); @@ -381,16 +342,8 @@ static void xan_wc3_decode_frame(XanContext *s) { /* 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; } }