lavc: introduce VideoDSPContext

Move some functions from dsputil. The idea is that videodsp contains
functions that are useful for a large and varied set of video decoders.
Currently, it contains emulated_edge_mc() and prefetch().

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

1 files changed, 93 insertions, 0 deletions

diff --git a/libavcodec/videodsp_template.c b/libavcodec/videodsp_template.c
new file mode 100644
index 0000000000..5d5a32ff60
--- /dev/null
+++ b/libavcodec/videodsp_template.c
@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2002-2004 Michael Niedermayer
+ * Copyright (C) 2012 Ronald S. Bultje
+ *
+ * This file is part of Libav.
+ *
+ * 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.
+ *
+ * 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "bit_depth_template.c"
+
+static void FUNC(ff_emulated_edge_mc)(uint8_t *buf, const uint8_t *src,
+                                      ptrdiff_t linesize,
+                                      int block_w, int block_h,
+                                      int src_x, int src_y, int w, int h)
+{
+    int x, y;
+    int start_y, start_x, end_y, end_x;
+
+    if (src_y >= h) {
+        src  += (h - 1 - src_y) * linesize;
+        src_y = h - 1;
+    } else if (src_y <= -block_h) {
+        src  += (1 - block_h - src_y) * linesize;
+        src_y = 1 - block_h;
+    }
+    if (src_x >= w) {
+        src  += (w - 1 - src_x) * sizeof(pixel);
+        src_x = w - 1;
+    } else if (src_x <= -block_w) {
+        src  += (1 - block_w - src_x) * sizeof(pixel);
+        src_x = 1 - block_w;
+    }
+
+    start_y = FFMAX(0, -src_y);
+    start_x = FFMAX(0, -src_x);
+    end_y = FFMIN(block_h, h-src_y);
+    end_x = FFMIN(block_w, w-src_x);
+    assert(start_y < end_y && block_h);
+    assert(start_x < end_x && block_w);
+
+    w    = end_x - start_x;
+    src += start_y * linesize + start_x * sizeof(pixel);
+    buf += start_x * sizeof(pixel);
+
+    // top
+    for (y = 0; y < start_y; y++) {
+        memcpy(buf, src, w * sizeof(pixel));
+        buf += linesize;
+    }
+
+    // copy existing part
+    for (; y < end_y; y++) {
+        memcpy(buf, src, w * sizeof(pixel));
+        src += linesize;
+        buf += linesize;
+    }
+
+    // bottom
+    src -= linesize;
+    for (; y < block_h; y++) {
+        memcpy(buf, src, w * sizeof(pixel));
+        buf += linesize;
+    }
+
+    buf -= block_h * linesize + start_x * sizeof(pixel);
+    while (block_h--) {
+        pixel *bufp = (pixel *) buf;
+
+        // left
+        for(x = 0; x < start_x; x++) {
+            bufp[x] = bufp[start_x];
+        }
+
+        // right
+        for (x = end_x; x < block_w; x++) {
+            bufp[x] = bufp[end_x - 1];
+        }
+        buf += linesize;
+    }
+}