X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavformat%2Faviobuf.c;h=29fccbea83b3b96f13374002ae16b1138ffb6929;hb=11de006babf735aafa3462d43dd2c02bb6ac6e2f;hp=da836c6fd5d3c865e9e806d0b3b67e9fdfa5af75;hpb=b522000e9b2ca36fe5b2751096b9a5f5ed8f87e6;p=ffmpeg

diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
index da836c6fd5d..29fccbea83b 100644
--- a/libavformat/aviobuf.c
+++ b/libavformat/aviobuf.c
@@ -40,28 +40,67 @@
  */
 #define SHORT_SEEK_THRESHOLD 4096
 
-static void *ffio_url_child_next(void *obj, void *prev)
+typedef struct AVIOInternal {
+    const AVClass *class;
+
+    char *protocol_whitelist;
+    char *protocol_blacklist;
+
+    URLContext *h;
+    const URLProtocol **protocols;
+} AVIOInternal;
+
+static void *io_priv_child_next(void *obj, void *prev)
+{
+    AVIOInternal *internal = obj;
+    return prev ? NULL : internal->h;
+}
+
+static const AVClass *io_priv_child_class_next(const AVClass *prev)
+{
+    return prev ? NULL : &ffurl_context_class;
+}
+
+#define OFFSET(x) offsetof(AVIOInternal, x)
+static const AVOption io_priv_options[] = {
+    { "protocol_whitelist", "A comma-separated list of allowed protocols",
+        OFFSET(protocol_whitelist), AV_OPT_TYPE_STRING },
+    { "protocol_blacklist", "A comma-separated list of forbidden protocols",
+        OFFSET(protocol_whitelist), AV_OPT_TYPE_STRING },
+    { NULL },
+};
+
+static const AVClass io_priv_class = {
+    .class_name       = "AVIOContext",
+    .item_name        = av_default_item_name,
+    .version          = LIBAVUTIL_VERSION_INT,
+    .option           = io_priv_options,
+    .child_next       = io_priv_child_next,
+    .child_class_next = io_priv_child_class_next,
+};
+
+static void *ff_avio_child_next(void *obj, void *prev)
 {
     AVIOContext *s = obj;
     return prev ? NULL : s->opaque;
 }
 
-static const AVClass *ffio_url_child_class_next(const AVClass *prev)
+static const AVClass *ff_avio_child_class_next(const AVClass *prev)
 {
-    return prev ? NULL : &ffurl_context_class;
+    return prev ? NULL : &io_priv_class;
 }
 
-static const AVOption ffio_url_options[] = {
+static const AVOption ff_avio_options[] = {
     { NULL },
 };
 
-const AVClass ffio_url_class = {
+const AVClass ff_avio_class = {
     .class_name = "AVIOContext",
     .item_name  = av_default_item_name,
     .version    = LIBAVUTIL_VERSION_INT,
-    .option     = ffio_url_options,
-    .child_next = ffio_url_child_next,
-    .child_class_next = ffio_url_child_class_next,
+    .option     = ff_avio_options,
+    .child_next = ff_avio_child_next,
+    .child_class_next = ff_avio_child_class_next,
 };
 
 static void fill_buffer(AVIOContext *s);
@@ -76,27 +115,31 @@ int ffio_init_context(AVIOContext *s,
                   int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
                   int64_t (*seek)(void *opaque, int64_t offset, int whence))
 {
-    s->buffer = buffer;
+    s->buffer      = buffer;
     s->buffer_size = buffer_size;
-    s->buf_ptr = buffer;
-    s->opaque = opaque;
+    s->buf_ptr     = buffer;
+    s->opaque      = opaque;
+
     url_resetbuf(s, write_flag ? AVIO_FLAG_WRITE : AVIO_FLAG_READ);
-    s->write_packet = write_packet;
-    s->read_packet = read_packet;
-    s->seek = seek;
-    s->pos = 0;
-    s->must_flush = 0;
-    s->eof_reached = 0;
-    s->error = 0;
-    s->seekable = AVIO_SEEKABLE_NORMAL;
+
+    s->write_packet    = write_packet;
+    s->read_packet     = read_packet;
+    s->seek            = seek;
+    s->pos             = 0;
+    s->must_flush      = 0;
+    s->eof_reached     = 0;
+    s->error           = 0;
+    s->seekable        = seek ? AVIO_SEEKABLE_NORMAL : 0;
     s->max_packet_size = 0;
-    s->update_checksum= NULL;
-    if(!read_packet && !write_flag){
-        s->pos = buffer_size;
+    s->update_checksum = NULL;
+
+    if (!read_packet && !write_flag) {
+        s->pos     = buffer_size;
         s->buf_end = s->buffer + buffer_size;
     }
     s->read_pause = NULL;
     s->read_seek  = NULL;
+
     return 0;
 }
 
@@ -120,15 +163,17 @@ AVIOContext *avio_alloc_context(
 static void flush_buffer(AVIOContext *s)
 {
     if (s->buf_ptr > s->buffer) {
-        if (s->write_packet && !s->error){
-            int ret= s->write_packet(s->opaque, s->buffer, s->buf_ptr - s->buffer);
-            if(ret < 0){
+        if (s->write_packet && !s->error) {
+            int ret = s->write_packet(s->opaque, s->buffer,
+                                      s->buf_ptr - s->buffer);
+            if (ret < 0) {
                 s->error = ret;
             }
         }
-        if(s->update_checksum){
-            s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_ptr - s->checksum_ptr);
-            s->checksum_ptr= s->buffer;
+        if (s->update_checksum) {
+            s->checksum     = s->update_checksum(s->checksum, s->checksum_ptr,
+                                                 s->buf_ptr - s->checksum_ptr);
+            s->checksum_ptr = s->buffer;
         }
         s->pos += s->buf_ptr - s->buffer;
     }
@@ -200,7 +245,7 @@ int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
     }
     offset1 = offset - pos;
     if (!s->must_flush &&
-        offset1 >= 0 && offset1 <= (s->buf_end - s->buffer)) {
+        offset1 >= 0 && offset1 < (s->buf_end - s->buffer)) {
         /* can do the seek inside the buffer */
         s->buf_ptr = s->buffer + offset1;
     } else if ((!s->seekable ||
@@ -215,12 +260,10 @@ int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
     } else {
         int64_t res;
 
-#if CONFIG_MUXERS || CONFIG_NETWORK
         if (s->write_flag) {
             flush_buffer(s);
             s->must_flush = 1;
         }
-#endif /* CONFIG_MUXERS || CONFIG_NETWORK */
         if (!s->seek)
             return AVERROR(EPIPE);
         if ((res = s->seek(s->opaque, offset, SEEK_SET)) < 0)
@@ -238,13 +281,13 @@ int64_t avio_size(AVIOContext *s)
 {
     int64_t size;
 
-    if(!s)
+    if (!s)
         return AVERROR(EINVAL);
 
     if (!s->seek)
         return AVERROR(ENOSYS);
     size = s->seek(s->opaque, 0, AVSEEK_SIZE);
-    if(size<0){
+    if (size < 0) {
         if ((size = s->seek(s->opaque, -1, SEEK_END)) < 0)
             return size;
         size++;
@@ -280,39 +323,47 @@ int avio_put_str(AVIOContext *s, const char *str)
     return len;
 }
 
-int avio_put_str16le(AVIOContext *s, const char *str)
-{
-    const uint8_t *q = str;
-    int ret = 0;
+#define PUT_STR16(type, write)                                   \
+    int avio_put_str16 ## type(AVIOContext * s, const char *str) \
+    {                                                            \
+        const uint8_t *q = str;                                  \
+        int ret          = 0;                                    \
+                                                                 \
+        while (*q) {                                             \
+            uint32_t ch;                                         \
+            uint16_t tmp;                                        \
+                                                                 \
+            GET_UTF8(ch, *q++, break; )                          \
+            PUT_UTF16(ch, tmp, write(s, tmp); ret += 2; )        \
+        }                                                        \
+        write(s, 0);                                             \
+        ret += 2;                                                \
+        return ret;                                              \
+    }
 
-    while (*q) {
-        uint32_t ch;
-        uint16_t tmp;
+PUT_STR16(le, avio_wl16)
+PUT_STR16(be, avio_wb16)
 
-        GET_UTF8(ch, *q++, break;)
-        PUT_UTF16(ch, tmp, avio_wl16(s, tmp);ret += 2;)
-    }
-    avio_wl16(s, 0);
-    ret += 2;
-    return ret;
-}
+#undef PUT_STR16
 
-int ff_get_v_length(uint64_t val){
-    int i=1;
+int ff_get_v_length(uint64_t val)
+{
+    int i = 1;
 
-    while(val>>=7)
+    while (val >>= 7)
         i++;
 
     return i;
 }
 
-void ff_put_v(AVIOContext *bc, uint64_t val){
-    int i= ff_get_v_length(val);
+void ff_put_v(AVIOContext *bc, uint64_t val)
+{
+    int i = ff_get_v_length(val);
 
-    while(--i>0)
-        avio_w8(bc, 128 | (val>>(7*i)));
+    while (--i > 0)
+        avio_w8(bc, 128 | (val >> (7 * i)));
 
-    avio_w8(bc, val&127);
+    avio_w8(bc, val & 127);
 }
 
 void avio_wl64(AVIOContext *s, uint64_t val)
@@ -355,11 +406,14 @@ void avio_wb24(AVIOContext *s, unsigned int val)
 
 static void fill_buffer(AVIOContext *s)
 {
-    uint8_t *dst= !s->max_packet_size && s->buf_end - s->buffer < s->buffer_size ? s->buf_end : s->buffer;
-    int len= s->buffer_size - (dst - s->buffer);
-    int max_buffer_size = s->max_packet_size ? s->max_packet_size : IO_BUFFER_SIZE;
-
-    /* can't fill the buffer without read_packet, just set EOF if appropiate */
+    uint8_t *dst        = !s->max_packet_size &&
+                          s->buf_end - s->buffer < s->buffer_size ?
+                          s->buf_end : s->buffer;
+    int len             = s->buffer_size - (dst - s->buffer);
+    int max_buffer_size = s->max_packet_size ?
+                          s->max_packet_size : IO_BUFFER_SIZE;
+
+    /* can't fill the buffer without read_packet, just set EOF if appropriate */
     if (!s->read_packet && s->buf_ptr >= s->buf_end)
         s->eof_reached = 1;
 
@@ -367,10 +421,11 @@ static void fill_buffer(AVIOContext *s)
     if (s->eof_reached)
         return;
 
-    if(s->update_checksum && dst == s->buffer){
-        if(s->buf_end > s->checksum_ptr)
-            s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_end - s->checksum_ptr);
-        s->checksum_ptr= s->buffer;
+    if (s->update_checksum && dst == s->buffer) {
+        if (s->buf_end > s->checksum_ptr)
+            s->checksum = s->update_checksum(s->checksum, s->checksum_ptr,
+                                             s->buf_end - s->checksum_ptr);
+        s->checksum_ptr = s->buffer;
     }
 
     /* make buffer smaller in case it ended up large after probing */
@@ -381,7 +436,7 @@ static void fill_buffer(AVIOContext *s)
         len = s->buffer_size;
     }
 
-    if(s->read_packet)
+    if (s->read_packet)
         len = s->read_packet(s->opaque, dst, len);
     else
         len = 0;
@@ -389,8 +444,8 @@ static void fill_buffer(AVIOContext *s)
         /* do not modify buffer if EOF reached so that a seek back can
            be done without rereading data */
         s->eof_reached = 1;
-        if(len<0)
-            s->error= len;
+        if (len < 0)
+            s->error = len;
     } else {
         s->pos += len;
         s->buf_ptr = dst;
@@ -404,10 +459,17 @@ unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
     return av_crc(av_crc_get_table(AV_CRC_32_IEEE), checksum, buf, len);
 }
 
+unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf,
+                                unsigned int len)
+{
+    return av_crc(av_crc_get_table(AV_CRC_16_ANSI_LE), checksum, buf, len);
+}
+
 unsigned long ffio_get_checksum(AVIOContext *s)
 {
-    s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_ptr - s->checksum_ptr);
-    s->update_checksum= NULL;
+    s->checksum = s->update_checksum(s->checksum, s->checksum_ptr,
+                                     s->buf_ptr - s->checksum_ptr);
+    s->update_checksum = NULL;
     return s->checksum;
 }
 
@@ -415,10 +477,10 @@ void ffio_init_checksum(AVIOContext *s,
                    unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len),
                    unsigned long checksum)
 {
-    s->update_checksum= update_checksum;
-    if(s->update_checksum){
-        s->checksum= checksum;
-        s->checksum_ptr= s->buf_ptr;
+    s->update_checksum = update_checksum;
+    if (s->update_checksum) {
+        s->checksum     = checksum;
+        s->checksum_ptr = s->buf_ptr;
     }
 }
 
@@ -441,7 +503,7 @@ int avio_read(AVIOContext *s, unsigned char *buf, int size)
         len = s->buf_end - s->buf_ptr;
         if (len > size)
             len = size;
-        if (len == 0) {
+        if (len == 0 || s->write_flag) {
             if(size > s->buffer_size && !s->update_checksum){
                 if(s->read_packet)
                     len = s->read_packet(s->opaque, buf, size);
@@ -459,7 +521,7 @@ int avio_read(AVIOContext *s, unsigned char *buf, int size)
                     s->buf_ptr = s->buffer;
                     s->buf_end = s->buffer/* + len*/;
                 }
-            }else{
+            } else {
                 fill_buffer(s);
                 len = s->buf_end - s->buf_ptr;
                 if (len == 0)
@@ -479,15 +541,49 @@ int avio_read(AVIOContext *s, unsigned char *buf, int size)
     return size1 - size;
 }
 
+int ffio_read_size(AVIOContext *s, unsigned char *buf, int size)
+{
+    int ret = avio_read(s, buf, size);
+    if (ret != size)
+        return AVERROR_INVALIDDATA;
+    return ret;
+}
+
+int ffio_read_indirect(AVIOContext *s, unsigned char *buf, int size, const unsigned char **data)
+{
+    if (s->buf_end - s->buf_ptr >= size && !s->write_flag) {
+        *data = s->buf_ptr;
+        s->buf_ptr += size;
+        return size;
+    } else {
+        *data = buf;
+        return avio_read(s, buf, size);
+    }
+}
+
 int ffio_read_partial(AVIOContext *s, unsigned char *buf, int size)
 {
     int len;
 
-    if(size<0)
+    if (size < 0)
         return -1;
 
+    if (s->read_packet && s->write_flag) {
+        len = s->read_packet(s->opaque, buf, size);
+        if (len > 0)
+            s->pos += len;
+        return len;
+    }
+
     len = s->buf_end - s->buf_ptr;
     if (len == 0) {
+        /* Reset the buf_end pointer to the start of the buffer, to make sure
+         * the fill_buffer call tries to read as much data as fits into the
+         * full buffer, instead of just what space is left after buf_end.
+         * This avoids returning partial packets at the end of the buffer,
+         * for packet based inputs.
+         */
+        s->buf_end = s->buf_ptr = s->buffer;
         fill_buffer(s);
         len = s->buf_end - s->buf_ptr;
     }
@@ -633,9 +729,44 @@ uint64_t ffio_read_varlen(AVIOContext *bc){
     return val;
 }
 
+static int io_read_packet(void *opaque, uint8_t *buf, int buf_size)
+{
+    AVIOInternal *internal = opaque;
+    return ffurl_read(internal->h, buf, buf_size);
+}
+
+static int io_write_packet(void *opaque, uint8_t *buf, int buf_size)
+{
+    AVIOInternal *internal = opaque;
+    return ffurl_write(internal->h, buf, buf_size);
+}
+
+static int64_t io_seek(void *opaque, int64_t offset, int whence)
+{
+    AVIOInternal *internal = opaque;
+    return ffurl_seek(internal->h, offset, whence);
+}
+
+static int io_read_pause(void *opaque, int pause)
+{
+    AVIOInternal *internal = opaque;
+    if (!internal->h->prot->url_read_pause)
+        return AVERROR(ENOSYS);
+    return internal->h->prot->url_read_pause(internal->h, pause);
+}
+
+static int64_t io_read_seek(void *opaque, int stream_index, int64_t timestamp, int flags)
+{
+    AVIOInternal *internal = opaque;
+    if (!internal->h->prot->url_read_seek)
+        return AVERROR(ENOSYS);
+    return internal->h->prot->url_read_seek(internal->h, stream_index, timestamp, flags);
+}
+
 int ffio_fdopen(AVIOContext **s, URLContext *h)
 {
-    uint8_t *buffer;
+    AVIOInternal *internal = NULL;
+    uint8_t *buffer = NULL;
     int buffer_size, max_packet_size;
 
     max_packet_size = h->max_packet_size;
@@ -648,20 +779,34 @@ int ffio_fdopen(AVIOContext **s, URLContext *h)
     if (!buffer)
         return AVERROR(ENOMEM);
 
-    *s = avio_alloc_context(buffer, buffer_size, h->flags & AVIO_FLAG_WRITE, h,
-                            ffurl_read, ffurl_write, ffurl_seek);
-    if (!*s) {
-        av_free(buffer);
-        return AVERROR(ENOMEM);
-    }
+    internal = av_mallocz(sizeof(*internal));
+    if (!internal)
+        goto fail;
+
+    internal->class = &io_priv_class;
+    internal->h = h;
+
+    av_opt_set_defaults(internal);
+
+    *s = avio_alloc_context(buffer, buffer_size, h->flags & AVIO_FLAG_WRITE,
+                            internal, io_read_packet, io_write_packet, io_seek);
+    if (!*s)
+        goto fail;
+
     (*s)->seekable = h->is_streamed ? 0 : AVIO_SEEKABLE_NORMAL;
     (*s)->max_packet_size = max_packet_size;
     if(h->prot) {
-        (*s)->read_pause = (int (*)(void *, int))h->prot->url_read_pause;
-        (*s)->read_seek  = (int64_t (*)(void *, int, int64_t, int))h->prot->url_read_seek;
+        (*s)->read_pause = io_read_pause;
+        (*s)->read_seek  = io_read_seek;
     }
-    (*s)->av_class = &ffio_url_class;
+    (*s)->av_class = &ff_avio_class;
     return 0;
+fail:
+    if (internal)
+        av_opt_free(internal);
+    av_freep(&internal);
+    av_freep(&buffer);
+    return AVERROR(ENOMEM);
 }
 
 int ffio_set_buf_size(AVIOContext *s, int buf_size)
@@ -740,29 +885,69 @@ int avio_open(AVIOContext **s, const char *filename, int flags)
 int avio_open2(AVIOContext **s, const char *filename, int flags,
                const AVIOInterruptCB *int_cb, AVDictionary **options)
 {
+    AVIOInternal *internal;
+    const URLProtocol **protocols;
+    char *proto_whitelist = NULL, *proto_blacklist = NULL;
+    AVDictionaryEntry *e;
     URLContext *h;
     int err;
 
-    err = ffurl_open(&h, filename, flags, int_cb, options);
-    if (err < 0)
+    if (options) {
+        e = av_dict_get(*options, "protocol_whitelist", NULL, 0);
+        if (e)
+            proto_whitelist = e->value;
+        e = av_dict_get(*options, "protocol_blacklist", NULL, 0);
+        if (e)
+            proto_blacklist = e->value;
+    }
+
+    protocols = ffurl_get_protocols(proto_whitelist, proto_blacklist);
+    if (!protocols)
+        return AVERROR(ENOMEM);
+
+    err = ffurl_open(&h, filename, flags, int_cb, options, protocols, NULL);
+    if (err < 0) {
+        av_freep(&protocols);
         return err;
+    }
+
     err = ffio_fdopen(s, h);
     if (err < 0) {
         ffurl_close(h);
+        av_freep(&protocols);
         return err;
     }
+
+    internal = (*s)->opaque;
+    internal->protocols = protocols;
+
+    if (options) {
+        err = av_opt_set_dict(internal, options);
+        if (err < 0) {
+            avio_closep(s);
+            return err;
+        }
+    }
+
     return 0;
 }
 
 int avio_close(AVIOContext *s)
 {
+    AVIOInternal *internal;
     URLContext *h;
 
     if (!s)
         return 0;
 
     avio_flush(s);
-    h = s->opaque;
+    internal = s->opaque;
+    h        = internal->h;
+
+    av_opt_free(internal);
+
+    av_freep(&internal->protocols);
+    av_freep(&s->opaque);
     av_freep(&s->buffer);
     av_free(s);
     return ffurl_close(h);
@@ -798,15 +983,14 @@ int avio_pause(AVIOContext *s, int pause)
 int64_t avio_seek_time(AVIOContext *s, int stream_index,
                        int64_t timestamp, int flags)
 {
-    URLContext *h = s->opaque;
     int64_t ret;
     if (!s->read_seek)
         return AVERROR(ENOSYS);
-    ret = s->read_seek(h, stream_index, timestamp, flags);
-    if(ret >= 0) {
+    ret = s->read_seek(s->opaque, stream_index, timestamp, flags);
+    if (ret >= 0) {
         int64_t pos;
         s->buf_ptr = s->buf_end; // Flush buffer
-        pos = s->seek(h, 0, SEEK_CUR);
+        pos = s->seek(s->opaque, 0, SEEK_CUR);
         if (pos >= 0)
             s->pos = pos;
         else if (pos != AVERROR(ENOSYS))
@@ -832,7 +1016,7 @@ static int dyn_buf_write(void *opaque, uint8_t *buf, int buf_size)
     /* reallocate buffer if needed */
     new_size = d->pos + buf_size;
     new_allocated_size = d->allocated_size;
-    if(new_size < d->pos || new_size > INT_MAX/2)
+    if (new_size < d->pos || new_size > INT_MAX/2)
         return -1;
     while (new_size > new_allocated_size) {
         if (!new_allocated_size)
@@ -842,9 +1026,12 @@ static int dyn_buf_write(void *opaque, uint8_t *buf, int buf_size)
     }
 
     if (new_allocated_size > d->allocated_size) {
-        d->buffer = av_realloc(d->buffer, new_allocated_size);
-        if(d->buffer == NULL)
-             return AVERROR(ENOMEM);
+        int err;
+        if ((err = av_reallocp(&d->buffer, new_allocated_size)) < 0) {
+            d->allocated_size = 0;
+            d->size = 0;
+            return err;
+        }
         d->allocated_size = new_allocated_size;
     }
     memcpy(d->buffer + d->pos, buf, buf_size);
@@ -861,8 +1048,8 @@ static int dyn_packet_buf_write(void *opaque, uint8_t *buf, int buf_size)
 
     /* packetized write: output the header */
     AV_WB32(buf1, buf_size);
-    ret= dyn_buf_write(opaque, buf1, 4);
-    if(ret < 0)
+    ret = dyn_buf_write(opaque, buf1, 4);
+    if (ret < 0)
         return ret;
 
     /* then the data */
@@ -888,7 +1075,7 @@ static int url_open_dyn_buf_internal(AVIOContext **s, int max_packet_size)
     DynBuffer *d;
     unsigned io_buffer_size = max_packet_size ? max_packet_size : 1024;
 
-    if(sizeof(DynBuffer) + io_buffer_size < io_buffer_size)
+    if (sizeof(DynBuffer) + io_buffer_size < io_buffer_size)
         return -1;
     d = av_mallocz(sizeof(DynBuffer) + io_buffer_size);
     if (!d)
@@ -919,22 +1106,71 @@ int ffio_open_dyn_packet_buf(AVIOContext **s, int max_packet_size)
 
 int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
 {
-    DynBuffer *d = s->opaque;
+    DynBuffer *d;
     int size;
-    static const char padbuf[FF_INPUT_BUFFER_PADDING_SIZE] = {0};
+    static const char padbuf[AV_INPUT_BUFFER_PADDING_SIZE] = {0};
     int padding = 0;
 
+    if (!s) {
+        *pbuffer = NULL;
+        return 0;
+    }
+
     /* don't attempt to pad fixed-size packet buffers */
     if (!s->max_packet_size) {
         avio_write(s, padbuf, sizeof(padbuf));
-        padding = FF_INPUT_BUFFER_PADDING_SIZE;
+        padding = AV_INPUT_BUFFER_PADDING_SIZE;
     }
 
     avio_flush(s);
 
+    d = s->opaque;
     *pbuffer = d->buffer;
     size = d->size;
     av_free(d);
     av_free(s);
     return size - padding;
 }
+
+void ffio_free_dyn_buf(AVIOContext **s)
+{
+    uint8_t *tmp;
+    if (!*s)
+        return;
+    avio_close_dyn_buf(*s, &tmp);
+    av_free(tmp);
+    *s = NULL;
+}
+
+static int null_buf_write(void *opaque, uint8_t *buf, int buf_size)
+{
+    DynBuffer *d = opaque;
+
+    d->pos += buf_size;
+    if (d->pos > d->size)
+        d->size = d->pos;
+    return buf_size;
+}
+
+int ffio_open_null_buf(AVIOContext **s)
+{
+    int ret = url_open_dyn_buf_internal(s, 0);
+    if (ret >= 0) {
+        AVIOContext *pb = *s;
+        pb->write_packet = null_buf_write;
+    }
+    return ret;
+}
+
+int ffio_close_null_buf(AVIOContext *s)
+{
+    DynBuffer *d = s->opaque;
+    int size;
+
+    avio_flush(s);
+
+    size = d->size;
+    av_free(d);
+    av_free(s);
+    return size;
+}