avcodec/packet: move AVPacketList definition and function helpers over from libavformat

And replace the flags parameter with a function callback that can be used to
copy the contents of the packet (e.g, av_packet_ref and av_packet_copy_props).

Signed-off-by: James Almer <jamrial@gmail.com>

3 files changed, 114 insertions, 0 deletions

diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
index 4801163227..e4ba403cf6 100644
--- a/libavcodec/avpacket.c
+++ b/libavcodec/avpacket.c
@@ -726,6 +726,73 @@ FF_ENABLE_DEPRECATION_WARNINGS
 #endif
 }
 
+int avpriv_packet_list_put(AVPacketList **packet_buffer,
+                           AVPacketList **plast_pktl,
+                           AVPacket      *pkt,
+                           int (*copy)(AVPacket *dst, const AVPacket *src),
+                           int flags)
+{
+    AVPacketList *pktl = av_mallocz(sizeof(AVPacketList));
+    int ret;
+
+    if (!pktl)
+        return AVERROR(ENOMEM);
+
+    if (copy) {
+        ret = copy(&pktl->pkt, pkt);
+        if (ret < 0) {
+            av_free(pktl);
+            return ret;
+        }
+    } else {
+        ret = av_packet_make_refcounted(pkt);
+        if (ret < 0) {
+            av_free(pktl);
+            return ret;
+        }
+        av_packet_move_ref(&pktl->pkt, pkt);
+    }
+
+    if (*packet_buffer)
+        (*plast_pktl)->next = pktl;
+    else
+        *packet_buffer = pktl;
+
+    /* Add the packet in the buffered packet list. */
+    *plast_pktl = pktl;
+    return 0;
+}
+
+int avpriv_packet_list_get(AVPacketList **pkt_buffer,
+                           AVPacketList **pkt_buffer_end,
+                           AVPacket      *pkt)
+{
+    AVPacketList *pktl;
+    if (!*pkt_buffer)
+        return AVERROR(EAGAIN);
+    pktl        = *pkt_buffer;
+    *pkt        = pktl->pkt;
+    *pkt_buffer = pktl->next;
+    if (!pktl->next)
+        *pkt_buffer_end = NULL;
+    av_freep(&pktl);
+    return 0;
+}
+
+void avpriv_packet_list_free(AVPacketList **pkt_buf, AVPacketList **pkt_buf_end)
+{
+    AVPacketList *tmp = *pkt_buf;
+
+    while (tmp) {
+        AVPacketList *pktl = tmp;
+        tmp = pktl->next;
+        av_packet_unref(&pktl->pkt);
+        av_freep(&pktl);
+    }
+    *pkt_buf     = NULL;
+    *pkt_buf_end = NULL;
+}
+
 int ff_side_data_set_encoder_stats(AVPacket *pkt, int quality, int64_t *error, int error_count, int pict_type)
 {
     uint8_t *side_data;
diff --git a/libavcodec/packet.h b/libavcodec/packet.h
index 0a19a0eff3..b9d4c9c2c8 100644
--- a/libavcodec/packet.h
+++ b/libavcodec/packet.h
@@ -393,6 +393,11 @@ typedef struct AVPacket {
 #endif
 } AVPacket;
 
+typedef struct AVPacketList {
+    AVPacket pkt;
+    struct AVPacketList *next;
+} AVPacketList;
+
 #define AV_PKT_FLAG_KEY     0x0001 ///< The packet contains a keyframe
 #define AV_PKT_FLAG_CORRUPT 0x0002 ///< The packet content is corrupted
 /**
diff --git a/libavcodec/packet_internal.h b/libavcodec/packet_internal.h
index cdb9a27f2f..832ddb4a61 100644
--- a/libavcodec/packet_internal.h
+++ b/libavcodec/packet_internal.h
@@ -23,6 +23,48 @@
 
 #include "packet.h"
 
+
+/**
+ * Append an AVPacket to the list.
+ *
+ * @param head  List head element
+ * @param tail  List tail element
+ * @param pkt   The packet being appended. The data described in it will
+ *              be made reference counted if it isn't already.
+ * @param copy  A callback to copy the contents of the packet to the list.
+                May be null, in which case the packet's reference will be
+                moved to the list.
+ * @return 0 on success, negative AVERROR value on failure. On failure,
+           the packet and the list are unchanged.
+ */
+int avpriv_packet_list_put(AVPacketList **head, AVPacketList **tail,
+                           AVPacket *pkt,
+                           int (*copy)(AVPacket *dst, const AVPacket *src),
+                           int flags);
+
+/**
+ * Remove the oldest AVPacket in the list and return it.
+ *
+ * @note The pkt will be overwritten completely on success. The caller
+ *       owns the packet and must unref it by itself.
+ *
+ * @param head List head element
+ * @param tail List tail element
+ * @param pkt  Pointer to an AVPacket struct
+ * @return 0 on success, and a packet is returned. AVERROR(EAGAIN) if
+ *         the list was empty.
+ */
+int avpriv_packet_list_get(AVPacketList **head, AVPacketList **tail,
+                           AVPacket *pkt);
+
+/**
+ * Wipe the list and unref all the packets in it.
+ *
+ * @param head List head element
+ * @param tail List tail element
+ */
+void avpriv_packet_list_free(AVPacketList **head, AVPacketList **tail);
+
 int ff_side_data_set_encoder_stats(AVPacket *pkt, int quality, int64_t *error, int error_count, int pict_type);
 
 int ff_side_data_set_prft(AVPacket *pkt, int64_t timestamp);