avcodec: add emuedge_linesize_type

Currently all uses of the emu edge code as well as the code itself
assume int linesize
changing some but not changing all would introduce a security issue
once all use this typedef a simple search and replace can be
done to switch them all to ptrdiff_t
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mpegvideo_motion.c

@@ -214,7 +214,8 @@ void mpeg_motion_internal(MpegEncContext *s,
 {
     uint8_t *ptr_y, *ptr_cb, *ptr_cr;
     int dxy, uvdxy, mx, my, src_x, src_y,
-        uvsrc_x, uvsrc_y, v_edge_pos, uvlinesize, linesize;
+        uvsrc_x, uvsrc_y, v_edge_pos;
+    emuedge_linesize_type uvlinesize, linesize;
 
 #if 0
 if(s->quarter_sample)

libavcodec/videodsp.h

@@ -29,6 +29,8 @@
 #include <stddef.h>
 #include <stdint.h>
 
+typedef int emuedge_linesize_type;
+
 #define EMULATED_EDGE(depth) \
 void ff_emulated_edge_mc_ ## depth (uint8_t *buf, const uint8_t *src, ptrdiff_t linesize,\
                          int block_w, int block_h,\

libavcodec/videodsp_template.c

@@ -27,7 +27,7 @@ void FUNC(ff_emulated_edge_mc)(uint8_t *buf, const uint8_t *src,
 {
     int x, y;
     int start_y, start_x, end_y, end_x;
-    int linesize = linesize_arg;
+    emuedge_linesize_type linesize = linesize_arg;
 
     if (!w || !h)
         return;

libavcodec/x86/videodsp_init.c

@@ -46,7 +46,7 @@ static av_always_inline void emulated_edge_mc(uint8_t *buf, const uint8_t *src,
                                               emu_edge_core_func *core_fn)
 {
     int start_y, start_x, end_y, end_x, src_y_add = 0;
-    int linesize = linesize_arg;
+    emuedge_linesize_type linesize = linesize_arg;
 
     if(!w || !h)
         return;