avcodec/zmbv: Call decode_intra directly

zmbv has only one function for decoding intra frames, namely
decode_intra; and yet up until now it has been called via a function
pointer. This has been changed.

This also removes spec-incompliant conversions between function pointers
and pointers of type void * and thereby fixes the warning "ISO C forbids
assignment between function pointer and ‘void *’" that GCC emits with
the -pedantic option.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/zmbv.c

@@ -69,8 +69,8 @@ typedef struct ZmbvContext {
     int stride;
     int bw, bh, bx, by;
     int decomp_len;
+    int got_keyframe;
     z_stream zstream;
-    int (*decode_intra)(struct ZmbvContext *c);
     int (*decode_xor)(struct ZmbvContext *c);
 } ZmbvContext;
 
@@ -425,8 +425,7 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPac
     c->flags = buf[0];
     buf++; len--;
     if (c->flags & ZMBV_KEYFRAME) {
-        void *decode_intra = NULL;
-        c->decode_intra= NULL;
+        c->got_keyframe = 0;
 
         if (len < 6)
             return AVERROR_INVALIDDATA;
@@ -436,7 +435,6 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPac
         c->fmt = buf[3];
         c->bw = buf[4];
         c->bh = buf[5];
-        c->decode_intra = NULL;
         c->decode_xor = NULL;
 
         buf += 6;
@@ -460,7 +458,6 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPac
         switch (c->fmt) {
         case ZMBV_FMT_8BPP:
             c->bpp = 8;
-            decode_intra = zmbv_decode_intra;
             c->decode_xor = zmbv_decode_xor_8;
             avctx->pix_fmt = AV_PIX_FMT_PAL8;
             c->stride = c->width;
@@ -468,7 +465,6 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPac
         case ZMBV_FMT_15BPP:
         case ZMBV_FMT_16BPP:
             c->bpp = 16;
-            decode_intra = zmbv_decode_intra;
             c->decode_xor = zmbv_decode_xor_16;
             if (c->fmt == ZMBV_FMT_15BPP)
                 avctx->pix_fmt = AV_PIX_FMT_RGB555LE;
@@ -479,7 +475,6 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPac
 #ifdef ZMBV_ENABLE_24BPP
         case ZMBV_FMT_24BPP:
             c->bpp = 24;
-            decode_intra = zmbv_decode_intra;
             c->decode_xor = zmbv_decode_xor_24;
             avctx->pix_fmt = AV_PIX_FMT_BGR24;
             c->stride = c->width * 3;
@@ -487,7 +482,6 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPac
 #endif //ZMBV_ENABLE_24BPP
         case ZMBV_FMT_32BPP:
             c->bpp = 32;
-            decode_intra = zmbv_decode_intra;
             c->decode_xor = zmbv_decode_xor_32;
             avctx->pix_fmt = AV_PIX_FMT_BGR0;
             c->stride = c->width * 4;
@@ -517,7 +511,7 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPac
         }
         memset(c->cur, 0, avctx->width * avctx->height * (c->bpp / 8));
         memset(c->prev, 0, avctx->width * avctx->height * (c->bpp / 8));
-        c->decode_intra= decode_intra;
+        c->got_keyframe = 1;
     }
     if (c->flags & ZMBV_KEYFRAME) {
         expected_size = avctx->width * avctx->height * (c->bpp / 8);
@@ -528,7 +522,7 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPac
         (c->flags & (ZMBV_DELTAPAL | ZMBV_KEYFRAME)))
         expected_size += 768;
 
-    if (!c->decode_intra) {
+    if (!c->got_keyframe) {
         av_log(avctx, AV_LOG_ERROR, "Error! Got no format or no keyframe!\n");
         return AVERROR_INVALIDDATA;
     }
@@ -564,7 +558,7 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPac
     if (c->flags & ZMBV_KEYFRAME) {
         frame->key_frame = 1;
         frame->pict_type = AV_PICTURE_TYPE_I;
-        c->decode_intra(c);
+        zmbv_decode_intra(c);
     } else {
         frame->key_frame = 0;
         frame->pict_type = AV_PICTURE_TYPE_P;