similar to codec23, this one alternatingly skips and writes bytes.
Signed-off-by: Manuel Lauss <manuel.la...@gmail.com>
---
libavcodec/sanm.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)
diff --git a/libavcodec/sanm.c b/libavcodec/sanm.c
index aca5bf49ec..6080144235 100644
--- a/libavcodec/sanm.c
+++ b/libavcodec/sanm.c
@@ -614,6 +614,49 @@ static int old_codec23(SANMVideoContext *ctx, int top, int
left, int width,
return 0;
}
+static int old_codec21(SANMVideoContext *ctx, int top, int left, int width,
+ int height)
+{
+ const uint32_t maxpxo = ctx->height * ctx->pitch;
+ uint8_t *dst = (uint8_t *)ctx->frm0, c;
+ int i, j, k, pc, sk, pxoff;
+
+ dst = (uint8_t *)ctx->frm0;
+ for (i = 0; i < height; i++) {
+ if (bytestream2_get_bytes_left(&ctx->gb) < 2)
+ return 0;
+ pxoff = left + ((top + i) * ctx->pitch);
+ k = bytestream2_get_le16u(&ctx->gb);
+ sk = 1;
+ pc = 0;
+ while (k > 0 && pc <= width) {
+ if (bytestream2_get_bytes_left(&ctx->gb) < 2)
+ return AVERROR_INVALIDDATA;
+ j = bytestream2_get_le16u(&ctx->gb);
+ k -= 2;
+ if (sk) {
+ pxoff += j;
+ pc += j;
+ } else {
+ if (bytestream2_get_bytes_left(&ctx->gb) < (j + 1))
+ return AVERROR_INVALIDDATA;
+ do {
+ c = bytestream2_get_byteu(&ctx->gb);
+ if (pxoff >=0 && pxoff < maxpxo) {
+ *(dst + pxoff) = c;
+ }
+ pxoff++;
+ pc++;
+ j--;
+ k--;
+ } while (j > -1);
+ }
+ sk ^= 1;
+ }
+ }
+ return 0;
+}
+
static int old_codec1(SANMVideoContext *ctx, int top,
int left, int width, int height, int opaque)
{
@@ -1393,6 +1436,8 @@ static int process_frame_obj(SANMVideoContext *ctx)
return old_codec1(ctx, top, left, w, h, codec == 3);
case 2:
return old_codec2(ctx, top, left, w, h);
+ case 21:
+ return old_codec21(ctx, top, left, w, h);
case 23:
return old_codec23(ctx, top, left, w, h, param, parm2);
case 37:
--
2.48.1
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