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/* |
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* RLE encoder |
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* Copyright (c) 2007 Bobby Bingham |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "libavutil/common.h" |
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#include "avcodec.h" |
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#include "rle.h" |
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239474 |
int ff_rle_count_pixels(const uint8_t *start, int len, int bpp, int same) |
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{ |
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const uint8_t *pos; |
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239474 |
int count = 1; |
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✓✓ |
9354597 |
for (pos = start + bpp; count < FFMIN(127, len); pos += bpp, count++) { |
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✓✓ |
9285053 |
if (same != !memcmp(pos - bpp, pos, bpp)) { |
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✓✓ |
268613 |
if (!same) { |
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/* if bpp == 1, then 0 1 1 0 is more efficiently encoded as a |
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* single raw block of pixels. For larger bpp, RLE is as good |
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* or better */ |
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✓✓✓✓
✓✓ |
129548 |
if (bpp == 1 && count + 1 < FFMIN(127, len) && *pos != *(pos + 1)) |
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continue; |
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/* if RLE can encode the next block better than as a raw block, |
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* back up and leave _all_ the identical pixels for RLE */ |
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30865 |
count--; |
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} |
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169930 |
break; |
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} |
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} |
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239474 |
return count; |
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} |
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int ff_rle_encode(uint8_t *outbuf, int out_size, const uint8_t *ptr, int bpp, |
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int w, int add_rep, int xor_rep, int add_raw, int xor_raw) |
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{ |
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int count, x; |
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7488 |
uint8_t *out = outbuf; |
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✓✓ |
60989 |
for (x = 0; x < w; x += count) { |
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/* see if we can encode the next set of pixels with RLE */ |
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✓✓ |
53514 |
if ((count = ff_rle_count_pixels(ptr, w - x, bpp, 1)) > 1) { |
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✗✓ |
5546 |
if (out + bpp + 1 > outbuf + out_size) |
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return -1; |
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*out++ = (count ^ xor_rep) + add_rep; |
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memcpy(out, ptr, bpp); |
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out += bpp; |
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} else { |
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/* fall back on uncompressed */ |
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count = ff_rle_count_pixels(ptr, w - x, bpp, 0); |
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✓✓ |
47968 |
if (out + bpp * count >= outbuf + out_size) |
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return -1; |
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47955 |
*out++ = (count ^ xor_raw) + add_raw; |
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memcpy(out, ptr, bpp * count); |
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out += bpp * count; |
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} |
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ptr += count * bpp; |
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} |
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7475 |
return out - outbuf; |
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} |