avcodec/jpeglsenc: Allocate buffers together

Having only one allocation that is not automatically freed in particular
means that one does not need to free the already allocated buffers
when allocating another one fails.

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

libavcodec/jpeglsenc.c

@@ -276,7 +276,6 @@ static int encode_picture_ls(AVCodecContext *avctx, AVPacket *pkt,
     PutByteContext pb;
     PutBitContext pb2;
     GetBitContext gb;
-    uint8_t *buf2 = NULL;
     const uint8_t *in;
     uint8_t *last = NULL;
     JLSState state = { 0 };
@@ -300,12 +299,13 @@ FF_ENABLE_DEPRECATION_WARNINGS
                                 AV_INPUT_BUFFER_MIN_SIZE, 0)) < 0)
         return ret;
 
-    buf2 = av_malloc(pkt->size);
-    if (!buf2)
-        goto memfail;
+    last = av_malloc((unsigned)pkt->size + FFABS(p->linesize[0]));
+    if (!last)
+        return AVERROR(ENOMEM);
+    memset(last, 0, FFABS(p->linesize[0]));
 
     bytestream2_init_writer(&pb, pkt->data, pkt->size);
-    init_put_bits(&pb2, buf2, pkt->size);
+    init_put_bits(&pb2, last + FFABS(p->linesize[0]), pkt->size);
 
     /* write our own JPEG header, can't use mjpeg_picture_header */
     put_marker_byteu(&pb, SOI);
@@ -340,10 +340,6 @@ FF_ENABLE_DEPRECATION_WARNINGS
 
     ls_store_lse(&state, &pb);
 
-    last = av_mallocz(FFABS(p->linesize[0]));
-    if (!last)
-        goto memfail;
-
     in = p->data[0];
     if (avctx->pix_fmt == AV_PIX_FMT_GRAY8) {
         int t = 0;
@@ -393,8 +389,6 @@ FF_ENABLE_DEPRECATION_WARNINGS
         }
     }
 
-    av_freep(&last);
-
     /* the specification says that after doing 0xff escaping unused bits in
      * the last byte must be set to 0, so just append 7 "optional" zero bits
      * to avoid special-casing. */
@@ -402,7 +396,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
     size = put_bits_count(&pb2);
     flush_put_bits(&pb2);
     /* do escape coding */
-    init_get_bits(&gb, buf2, size);
+    init_get_bits(&gb, pb2.buf, size);
     size -= 7;
     while (get_bits_count(&gb) < size) {
         int v;
@@ -413,7 +407,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
             bytestream2_put_byte(&pb, v);
         }
     }
-    av_freep(&buf2);
+    av_freep(&last);
 
     /* End of image */
     put_marker_byte(&pb, EOI);
@@ -424,11 +418,6 @@ FF_ENABLE_DEPRECATION_WARNINGS
     pkt->flags |= AV_PKT_FLAG_KEY;
     *got_packet = 1;
     return 0;
-
-memfail:
-    av_freep(&buf2);
-    av_freep(&last);
-    return AVERROR(ENOMEM);
 }
 
 static av_cold int encode_init_ls(AVCodecContext *ctx)