1 files changed, 84 insertions, 0 deletions
diff --git a/contrib/ffmpeg/libavcodec/rle.c b/contrib/ffmpeg/libavcodec/rle.c
new file mode 100644
index 000000000..2fb0d0e48
--- /dev/null
+++ b/contrib/ffmpeg/libavcodec/rle.c
@@ -0,0 +1,84 @@
+/*
+ * RLE encoder
+ * Copyright (c) 2007 Bobby Bingham
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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,
+ * 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
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#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)
+{
+    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))
+                    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 --;
+            }
+            break;
+        }
+    }
+
+    return count;
+}
+
+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 = outbuf;
+
+    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_rep) + add_rep;
+            memcpy(out, ptr, bpp);
+            out += bpp;
+        } else {
+            /* fall back on uncompressed */
+            count = count_pixels(ptr, w-x, bpp, 0);
+            *out++ = (count ^ xor_raw) + add_raw;
+
+            if(out + bpp*count > outbuf + out_size) return -1;
+            memcpy(out, ptr, bpp * count);
+            out += bpp * count;
+        }
+
+        ptr += count * bpp;
+    }
+
+    return out - outbuf;
+}