[FFmpeg-devel] [PATCH 7/9] avformat/matroskadec: Replace switch with array

[Andreas Rheinhardt]

This simplification reduces codesize.
(It even reduces the size of .rodata here, because
the jump table used by the compiler is bigger than
the actual array.)

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
---
 libavformat/matroskadec.c | 47 +++++++++------------------------------
 1 file changed, 11 insertions(+), 36 deletions(-)

diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 98695479c6..e6797b2f57 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -2165,6 +2165,15 @@ static void mkv_stereo_mode_display_mul(int stereo_mode,
 
 static int mkv_stereo3d_conv(AVStream *st, MatroskaVideoStereoModeType stereo_mode)
 {
+    static const struct {
+        char type;
+        char flags;
+    } stereo_mode_conv [] = {
+#define STEREO_MODE_CONV(STEREOMODETYPE, STEREO3DTYPE, FLAGS, WDIV, HDIV, WEBM) \
+    [(STEREOMODETYPE)] = { .type = (STEREO3DTYPE), .flags = (FLAGS) },
+#define IGNORE(STEREOMODETYPE, WDIV, HDIV, WEBM)
+        STEREOMODE_STEREO3D_MAPPING(STEREO_MODE_CONV, IGNORE)
+    };
     AVStereo3D *stereo;
     int ret;
 
@@ -2172,42 +2181,8 @@ static int mkv_stereo3d_conv(AVStream *st, MatroskaVideoStereoModeType stereo_mo
     if (!stereo)
         return AVERROR(ENOMEM);
 
-    // note: the missing breaks are intentional
-    switch (stereo_mode) {
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_MONO:
-        stereo->type = AV_STEREO3D_2D;
-        break;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_RIGHT_LEFT:
-        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_LEFT_RIGHT:
-        stereo->type = AV_STEREO3D_SIDEBYSIDE;
-        break;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_BOTTOM_TOP:
-        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_TOP_BOTTOM:
-        stereo->type = AV_STEREO3D_TOPBOTTOM;
-        break;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_CHECKERBOARD_RL:
-        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_CHECKERBOARD_LR:
-        stereo->type = AV_STEREO3D_CHECKERBOARD;
-        break;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_ROW_INTERLEAVED_RL:
-        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_ROW_INTERLEAVED_LR:
-        stereo->type = AV_STEREO3D_LINES;
-        break;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_COL_INTERLEAVED_RL:
-        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_COL_INTERLEAVED_LR:
-        stereo->type = AV_STEREO3D_COLUMNS;
-        break;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_BOTH_EYES_BLOCK_RL:
-        stereo->flags |= AV_STEREO3D_FLAG_INVERT;
-    case MATROSKA_VIDEO_STEREOMODE_TYPE_BOTH_EYES_BLOCK_LR:
-        stereo->type = AV_STEREO3D_FRAMESEQUENCE;
-        break;
-    }
+    stereo->type  = stereo_mode_conv[stereo_mode].type;
+    stereo->flags = stereo_mode_conv[stereo_mode].flags;
 
     ret = av_stream_add_side_data(st, AV_PKT_DATA_STEREO3D, (uint8_t *)stereo,
                                   sizeof(*stereo));
-- 
2.34.1