* RLE encoder
* Copyright (c) 2007 Bobby Bingham
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav 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,
+ * Libav 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
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
*/
+
+#include "libavutil/common.h"
+
#include "avcodec.h"
#include "rle.h"
-/**
- * Count up to 127 consecutive pixels which are either all the same or
- * all differ from the previous and next pixels.
- * @param start Pointer to the first pixel
- * @param len Maximum number of pixels
- * @param bpp Bytes per pixel
- * @param same 1 if searching for identical pixel values. 0 for differing
- * @return Number of matching consecutive pixels found
- */
-static int count_pixels(const uint8_t *start, int len, int bpp, int same)
+int ff_rle_count_pixels(const uint8_t *start, int len, int bpp, int same)
{
const uint8_t *pos;
int count = 1;
- for(pos = start + bpp; count < FFMIN(128, len); pos += bpp, count ++) {
- if(same != !memcmp(pos-bpp, pos, bpp)) {
- if(!same) {
- /* if bpp == 1, then 0 1 1 0 is more efficiently encoded as a single
- * raw block of pixels. for larger bpp, RLE is as good or better */
- if(bpp == 1 && count + 1 < FFMIN(128, len) && *pos != *(pos+1))
+ for (pos = start + bpp; count < FFMIN(127, len); pos += bpp, count++) {
+ if (same != !memcmp(pos - bpp, pos, bpp)) {
+ if (!same) {
+ /* if bpp == 1, then 0 1 1 0 is more efficiently encoded as a
+ * single raw block of pixels. For larger bpp, RLE is as good
+ * or better */
+ if (bpp == 1 && count + 1 < FFMIN(127, len) && *pos != *(pos + 1))
continue;
/* if RLE can encode the next block better than as a raw block,
* back up and leave _all_ the identical pixels for RLE */
- count --;
+ count--;
}
break;
}
return count;
}
-/**
- * RLE compress the row, with maximum size of out_size. Value before repeated bytes is (count ^ xor) + add.
- * @param outbuf Output buffer
- * @param out_size Maximum output size
- * @param ptr Input buffer
- * @param bpp Bytes per pixel
- * @param w Image width
- * @return Size of output in bytes, or -1 if larger than out_size
- */
-int ff_rle_encode(uint8_t *outbuf, int out_size, const uint8_t *ptr , int bpp, int w, int8_t add, uint8_t xor)
+int ff_rle_encode(uint8_t *outbuf, int out_size, const uint8_t *ptr, int bpp,
+ int w, int add_rep, int xor_rep, int add_raw, int xor_raw)
{
int count, x;
- uint8_t *out;
-
- out = outbuf;
+ uint8_t *out = outbuf;
+ for (x = 0; x < w; x += count) {
+ /* see if we can encode the next set of pixels with RLE */
+ if ((count = ff_rle_count_pixels(ptr, w - x, bpp, 1)) > 1) {
+ if (out + bpp + 1 > outbuf + out_size)
+ return -1;
- for(x = 0; x < w; x += count) {
- /* see if we can encode the next set of pixels with RLE */
- if((count = count_pixels(ptr, w-x, bpp, 1)) > 1) {
- if(out + bpp + 1 > outbuf + out_size) return -1;
- *out++ = (count ^ xor) + add;
- memcpy(out, ptr, bpp);
- out += bpp;
- } else {
- /* fall back on uncompressed */
- count = count_pixels(ptr, w-x, bpp, 0);
- *out++ = count - 1;
+ *out++ = (count ^ xor_rep) + add_rep;
+ memcpy(out, ptr, bpp);
+ out += bpp;
+ } else {
+ /* fall back on uncompressed */
+ count = ff_rle_count_pixels(ptr, w - x, bpp, 0);
+ if (out + bpp * count >= outbuf + out_size)
+ return -1;
- if(out + bpp*count > outbuf + out_size) return -1;
- memcpy(out, ptr, bpp * count);
- out += bpp * count;
+ *out++ = (count ^ xor_raw) + add_raw;
+ memcpy(out, ptr, bpp * count);
+ out += bpp * count;
}
ptr += count * bpp;