X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavformat%2Faviobuf.c;h=df765078662c130ef1cfedb5820e748f676c4e19;hb=81bd4119652ce3911c6604f3421a46c677d6c10f;hp=993ba449f05dadb6ec9c05b8729f5ab98ec6fa72;hpb=a965c478b2b2fe7d9d0a2c60561bb4ee171a2119;p=ffmpeg

diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
index 993ba449f05..df765078662 100644
--- a/libavformat/aviobuf.c
+++ b/libavformat/aviobuf.c
@@ -2,26 +2,44 @@
  * Buffered I/O for ffmpeg system
  * Copyright (c) 2000,2001 Fabrice Bellard
  *
- * This library is free software; you can redistribute it and/or
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
+ * version 2.1 of the License, or (at your option) any later version.
  *
- * This library is distributed in the hope that it will be useful,
+ * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
+
+#include "libavutil/crc.h"
+#include "libavutil/intreadwrite.h"
 #include "avformat.h"
 #include "avio.h"
+#include "internal.h"
 #include <stdarg.h>
 
 #define IO_BUFFER_SIZE 32768
 
+/**
+ * Do seeks within this distance ahead of the current buffer by skipping
+ * data instead of calling the protocol seek function, for seekable
+ * protocols.
+ */
+#define SHORT_SEEK_THRESHOLD 4096
+
+static void fill_buffer(ByteIOContext *s);
+#if !FF_API_URL_RESETBUF
+static int url_resetbuf(ByteIOContext *s, int flags);
+#endif
+
 int init_put_byte(ByteIOContext *s,
                   unsigned char *buffer,
                   int buffer_size,
@@ -29,17 +47,13 @@ int init_put_byte(ByteIOContext *s,
                   void *opaque,
                   int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
                   int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
-                  int (*seek)(void *opaque, offset_t offset, int whence))
+                  int64_t (*seek)(void *opaque, int64_t offset, int whence))
 {
     s->buffer = buffer;
     s->buffer_size = buffer_size;
     s->buf_ptr = buffer;
-    s->write_flag = write_flag;
-    if (!s->write_flag) 
-        s->buf_end = buffer;
-    else
-        s->buf_end = buffer + buffer_size;
     s->opaque = opaque;
+    url_resetbuf(s, write_flag ? URL_WRONLY : URL_RDONLY);
     s->write_packet = write_packet;
     s->read_packet = read_packet;
     s->seek = seek;
@@ -50,11 +64,30 @@ int init_put_byte(ByteIOContext *s,
     s->is_streamed = 0;
     s->max_packet_size = 0;
     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;
 }
-                  
 
-#ifdef CONFIG_ENCODERS
+ByteIOContext *av_alloc_put_byte(
+                  unsigned char *buffer,
+                  int buffer_size,
+                  int write_flag,
+                  void *opaque,
+                  int (*read_packet)(void *opaque, uint8_t *buf, int buf_size),
+                  int (*write_packet)(void *opaque, uint8_t *buf, int buf_size),
+                  int64_t (*seek)(void *opaque, int64_t offset, int whence))
+{
+    ByteIOContext *s = av_mallocz(sizeof(ByteIOContext));
+    init_put_byte(s, buffer, buffer_size, write_flag, opaque,
+                  read_packet, write_packet, seek);
+    return s;
+}
+
 static void flush_buffer(ByteIOContext *s)
 {
     if (s->buf_ptr > s->buffer) {
@@ -76,22 +109,32 @@ static void flush_buffer(ByteIOContext *s)
 void put_byte(ByteIOContext *s, int b)
 {
     *(s->buf_ptr)++ = b;
-    if (s->buf_ptr >= s->buf_end) 
+    if (s->buf_ptr >= s->buf_end)
         flush_buffer(s);
 }
 
-void put_buffer(ByteIOContext *s, const unsigned char *buf, int size)
+void put_nbyte(ByteIOContext *s, int b, int count)
 {
-    int len;
+    while (count > 0) {
+        int len = FFMIN(s->buf_end - s->buf_ptr, count);
+        memset(s->buf_ptr, b, len);
+        s->buf_ptr += len;
+
+        if (s->buf_ptr >= s->buf_end)
+            flush_buffer(s);
+
+        count -= len;
+    }
+}
 
+void put_buffer(ByteIOContext *s, const unsigned char *buf, int size)
+{
     while (size > 0) {
-        len = (s->buf_end - s->buf_ptr);
-        if (len > size)
-            len = size;
+        int len = FFMIN(s->buf_end - s->buf_ptr, size);
         memcpy(s->buf_ptr, buf, len);
         s->buf_ptr += len;
 
-        if (s->buf_ptr >= s->buf_end) 
+        if (s->buf_ptr >= s->buf_end)
             flush_buffer(s);
 
         buf += len;
@@ -104,96 +147,108 @@ void put_flush_packet(ByteIOContext *s)
     flush_buffer(s);
     s->must_flush = 0;
 }
-#endif //CONFIG_ENCODERS
 
-offset_t url_fseek(ByteIOContext *s, offset_t offset, int whence)
+int64_t url_fseek(ByteIOContext *s, int64_t offset, int whence)
 {
-    offset_t offset1;
+    int64_t offset1;
+    int64_t pos;
+    int force = whence & AVSEEK_FORCE;
+    whence &= ~AVSEEK_FORCE;
+
+    if(!s)
+        return AVERROR(EINVAL);
+
+    pos = s->pos - (s->write_flag ? 0 : (s->buf_end - s->buffer));
 
     if (whence != SEEK_CUR && whence != SEEK_SET)
-        return -EINVAL;
-    
-#ifdef CONFIG_ENCODERS
-    if (s->write_flag) {
-        if (whence == SEEK_CUR) {
-            offset1 = s->pos + (s->buf_ptr - s->buffer);
-            if (offset == 0)
-                return offset1;
-            offset += offset1;
-        }
-        offset1 = offset - s->pos;
-        if (!s->must_flush && 
-            offset1 >= 0 && offset1 < (s->buf_end - s->buffer)) {
-            /* can do the seek inside the buffer */
-            s->buf_ptr = s->buffer + offset1;
-        } else {
-            if (!s->seek)
-                return -EPIPE;
+        return AVERROR(EINVAL);
+
+    if (whence == SEEK_CUR) {
+        offset1 = pos + (s->buf_ptr - s->buffer);
+        if (offset == 0)
+            return offset1;
+        offset += offset1;
+    }
+    offset1 = offset - pos;
+    if (!s->must_flush &&
+        offset1 >= 0 && offset1 <= (s->buf_end - s->buffer)) {
+        /* can do the seek inside the buffer */
+        s->buf_ptr = s->buffer + offset1;
+    } else if ((s->is_streamed ||
+               offset1 <= s->buf_end + SHORT_SEEK_THRESHOLD - s->buffer) &&
+               !s->write_flag && offset1 >= 0 &&
+              (whence != SEEK_END || force)) {
+        while(s->pos < offset && !s->eof_reached)
+            fill_buffer(s);
+        if (s->eof_reached)
+            return AVERROR_EOF;
+        s->buf_ptr = s->buf_end + offset - s->pos;
+    } else {
+        int64_t res;
+
+#if CONFIG_MUXERS || CONFIG_NETWORK
+        if (s->write_flag) {
             flush_buffer(s);
             s->must_flush = 1;
-            s->buf_ptr = s->buffer;
-            s->seek(s->opaque, offset, SEEK_SET);
-            s->pos = offset;
-        }
-    } else 
-#endif //CONFIG_ENCODERS
-    {
-        if (whence == SEEK_CUR) {
-            offset1 = s->pos - (s->buf_end - s->buffer) + (s->buf_ptr - s->buffer);
-            if (offset == 0)
-                return offset1;
-            offset += offset1;
         }
-        offset1 = offset - (s->pos - (s->buf_end - s->buffer));
-        if (offset1 >= 0 && offset1 <= (s->buf_end - s->buffer)) {
-            /* can do the seek inside the buffer */
-            s->buf_ptr = s->buffer + offset1;
-        } else {
-            if (!s->seek)
-                return -EPIPE;
-            s->buf_ptr = s->buffer;
+#endif /* CONFIG_MUXERS || CONFIG_NETWORK */
+        if (!s->seek)
+            return AVERROR(EPIPE);
+        if ((res = s->seek(s->opaque, offset, SEEK_SET)) < 0)
+            return res;
+        if (!s->write_flag)
             s->buf_end = s->buffer;
-            if (s->seek(s->opaque, offset, SEEK_SET) == (offset_t)-EPIPE)
-                return -EPIPE;
-            s->pos = offset;
-        }
-        s->eof_reached = 0;
+        s->buf_ptr = s->buffer;
+        s->pos = offset;
     }
+    s->eof_reached = 0;
     return offset;
 }
 
-void url_fskip(ByteIOContext *s, offset_t offset)
+int url_fskip(ByteIOContext *s, int64_t offset)
 {
-    url_fseek(s, offset, SEEK_CUR);
+    int64_t ret = url_fseek(s, offset, SEEK_CUR);
+    return ret < 0 ? ret : 0;
 }
 
-offset_t url_ftell(ByteIOContext *s)
+int64_t url_ftell(ByteIOContext *s)
 {
     return url_fseek(s, 0, SEEK_CUR);
 }
 
-offset_t url_fsize(ByteIOContext *s)
+int64_t url_fsize(ByteIOContext *s)
 {
-    offset_t size;
-    
+    int64_t size;
+
+    if(!s)
+        return AVERROR(EINVAL);
+
     if (!s->seek)
-        return -EPIPE;
-    size = s->seek(s->opaque, -1, SEEK_END) + 1;
-    s->seek(s->opaque, s->pos, SEEK_SET);
+        return AVERROR(ENOSYS);
+    size = s->seek(s->opaque, 0, AVSEEK_SIZE);
+    if(size<0){
+        if ((size = s->seek(s->opaque, -1, SEEK_END)) < 0)
+            return size;
+        size++;
+        s->seek(s->opaque, s->pos, SEEK_SET);
+    }
     return size;
 }
 
 int url_feof(ByteIOContext *s)
 {
+    if(!s)
+        return 0;
     return s->eof_reached;
 }
 
 int url_ferror(ByteIOContext *s)
 {
+    if(!s)
+        return 0;
     return s->error;
 }
 
-#ifdef CONFIG_ENCODERS
 void put_le32(ByteIOContext *s, unsigned int val)
 {
     put_byte(s, val);
@@ -210,17 +265,6 @@ void put_be32(ByteIOContext *s, unsigned int val)
     put_byte(s, val);
 }
 
-/* IEEE format is assumed */
-void put_be64_double(ByteIOContext *s, double val)
-{
-    union {
-        double d;
-        uint64_t ull;
-    } u;
-    u.d = val;
-    put_be64(s, u.ull);
-}
-
 void put_strz(ByteIOContext *s, const char *str)
 {
     if (str)
@@ -229,6 +273,24 @@ void put_strz(ByteIOContext *s, const char *str)
         put_byte(s, 0);
 }
 
+int ff_get_v_length(uint64_t val){
+    int i=1;
+
+    while(val>>=7)
+        i++;
+
+    return i;
+}
+
+void ff_put_v(ByteIOContext *bc, uint64_t val){
+    int i= ff_get_v_length(val);
+
+    while(--i>0)
+        put_byte(bc, 128 | (val>>(7*i)));
+
+    put_byte(bc, val&127);
+}
+
 void put_le64(ByteIOContext *s, uint64_t val)
 {
     put_le32(s, (uint32_t)(val & 0xffffffff));
@@ -253,85 +315,109 @@ void put_be16(ByteIOContext *s, unsigned int val)
     put_byte(s, val);
 }
 
+void put_le24(ByteIOContext *s, unsigned int val)
+{
+    put_le16(s, val & 0xffff);
+    put_byte(s, val >> 16);
+}
+
+void put_be24(ByteIOContext *s, unsigned int val)
+{
+    put_be16(s, val >> 8);
+    put_byte(s, val);
+}
+
 void put_tag(ByteIOContext *s, const char *tag)
 {
     while (*tag) {
         put_byte(s, *tag++);
     }
 }
-#endif //CONFIG_ENCODERS
 
 /* Input stream */
 
 static void fill_buffer(ByteIOContext *s)
 {
-    int len;
+    uint8_t *dst= !s->max_packet_size && s->buf_end - s->buffer < s->buffer_size ? s->buf_ptr : 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;
 
     /* no need to do anything if EOF already reached */
     if (s->eof_reached)
         return;
 
-    if(s->update_checksum){
-        s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_end - s->checksum_ptr);
+    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;
     }
 
-    len = s->read_packet(s->opaque, s->buffer, s->buffer_size);
+    /* make buffer smaller in case it ended up large after probing */
+    if (s->buffer_size > max_buffer_size) {
+        url_setbufsize(s, max_buffer_size);
+
+        s->checksum_ptr = dst = s->buffer;
+        len = s->buffer_size;
+    }
+
+    if(s->read_packet)
+        len = s->read_packet(s->opaque, dst, len);
+    else
+        len = 0;
     if (len <= 0) {
         /* 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 = s->buffer;
-        s->buf_end = s->buffer + len;
+        s->buf_ptr = dst;
+        s->buf_end = dst + len;
     }
 }
 
-unsigned long get_checksum(ByteIOContext *s){
+unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
+                                    unsigned int len)
+{
+    return av_crc(av_crc_get_table(AV_CRC_32_IEEE), checksum, buf, len);
+}
+
+unsigned long get_checksum(ByteIOContext *s)
+{
     s->checksum= s->update_checksum(s->checksum, s->checksum_ptr, s->buf_ptr - s->checksum_ptr);
     s->update_checksum= NULL;
     return s->checksum;
 }
 
-void init_checksum(ByteIOContext *s, unsigned long (*update_checksum)(unsigned long c, const uint8_t *p, unsigned int len), unsigned long checksum){
+void init_checksum(ByteIOContext *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= s->update_checksum(checksum, NULL, 0);
+        s->checksum= checksum;
         s->checksum_ptr= s->buf_ptr;
     }
 }
 
-/* NOTE: return 0 if EOF, so you cannot use it if EOF handling is
-   necessary */
 /* XXX: put an inline version */
 int get_byte(ByteIOContext *s)
 {
-    if (s->buf_ptr < s->buf_end) {
-        return *s->buf_ptr++;
-    } else {
+    if (s->buf_ptr >= s->buf_end)
         fill_buffer(s);
-        if (s->buf_ptr < s->buf_end)
-            return *s->buf_ptr++;
-        else
-            return 0;
-    }
+    if (s->buf_ptr < s->buf_end)
+        return *s->buf_ptr++;
+    return 0;
 }
 
-/* NOTE: return URL_EOF (-1) if EOF */
 int url_fgetc(ByteIOContext *s)
 {
-    if (s->buf_ptr < s->buf_end) {
-        return *s->buf_ptr++;
-    } else {
+    if (s->buf_ptr >= s->buf_end)
         fill_buffer(s);
-        if (s->buf_ptr < s->buf_end)
-            return *s->buf_ptr++;
-        else
-            return URL_EOF;
-    }
+    if (s->buf_ptr < s->buf_end)
+        return *s->buf_ptr++;
+    return URL_EOF;
 }
 
 int get_buffer(ByteIOContext *s, unsigned char *buf, int size)
@@ -345,7 +431,8 @@ int get_buffer(ByteIOContext *s, unsigned char *buf, int size)
             len = size;
         if (len == 0) {
             if(size > s->buffer_size && !s->update_checksum){
-                len = s->read_packet(s->opaque, buf, size);
+                if(s->read_packet)
+                    len = s->read_packet(s->opaque, buf, size);
                 if (len <= 0) {
                     /* do not modify buffer if EOF reached so that a seek back can
                     be done without rereading data */
@@ -373,13 +460,17 @@ int get_buffer(ByteIOContext *s, unsigned char *buf, int size)
             size -= len;
         }
     }
+    if (size1 == size) {
+        if (url_ferror(s)) return url_ferror(s);
+        if (url_feof(s))   return AVERROR_EOF;
+    }
     return size1 - size;
 }
 
 int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size)
 {
     int len;
-    
+
     if(size<0)
         return -1;
 
@@ -392,6 +483,10 @@ int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size)
         len = size;
     memcpy(buf, s->buf_ptr, len);
     s->buf_ptr += len;
+    if (!len) {
+        if (url_ferror(s)) return url_ferror(s);
+        if (url_feof(s))   return AVERROR_EOF;
+    }
     return len;
 }
 
@@ -403,13 +498,19 @@ unsigned int get_le16(ByteIOContext *s)
     return val;
 }
 
-unsigned int get_le32(ByteIOContext *s)
+unsigned int get_le24(ByteIOContext *s)
 {
     unsigned int val;
-    val = get_byte(s);
-    val |= get_byte(s) << 8;
+    val = get_le16(s);
     val |= get_byte(s) << 16;
-    val |= get_byte(s) << 24;
+    return val;
+}
+
+unsigned int get_le32(ByteIOContext *s)
+{
+    unsigned int val;
+    val = get_le16(s);
+    val |= get_le16(s) << 16;
     return val;
 }
 
@@ -429,25 +530,19 @@ unsigned int get_be16(ByteIOContext *s)
     return val;
 }
 
-unsigned int get_be32(ByteIOContext *s)
+unsigned int get_be24(ByteIOContext *s)
 {
     unsigned int val;
-    val = get_byte(s) << 24;
-    val |= get_byte(s) << 16;
-    val |= get_byte(s) << 8;
+    val = get_be16(s) << 8;
     val |= get_byte(s);
     return val;
 }
-
-double get_be64_double(ByteIOContext *s)
+unsigned int get_be32(ByteIOContext *s)
 {
-    union {
-        double d;
-        uint64_t ull;
-    } u;
-
-    u.ull = get_be64(s);
-    return u.d;
+    unsigned int val;
+    val = get_be16(s) << 16;
+    val |= get_be16(s);
+    return val;
 }
 
 char *get_strz(ByteIOContext *s, char *buf, int maxlen)
@@ -459,12 +554,27 @@ char *get_strz(ByteIOContext *s, char *buf, int maxlen)
         if (i < maxlen-1)
             buf[i++] = c;
     }
-    
+
     buf[i] = 0; /* Ensure null terminated, but may be truncated */
 
     return buf;
 }
 
+int ff_get_line(ByteIOContext *s, char *buf, int maxlen)
+{
+    int i = 0;
+    char c;
+
+    do {
+        c = get_byte(s);
+        if (c && i < maxlen-1)
+            buf[i++] = c;
+    } while (c != '\n' && c);
+
+    buf[i] = 0;
+    return i;
+}
+
 uint64_t get_be64(ByteIOContext *s)
 {
     uint64_t val;
@@ -473,37 +583,22 @@ uint64_t get_be64(ByteIOContext *s)
     return val;
 }
 
-/* link with avio functions */
+uint64_t ff_get_v(ByteIOContext *bc){
+    uint64_t val = 0;
+    int tmp;
 
-#ifdef CONFIG_ENCODERS
-static int url_write_packet(void *opaque, uint8_t *buf, int buf_size)
-{
-    URLContext *h = opaque;
-    return url_write(h, buf, buf_size);
-}
-#else
-#define	url_write_packet NULL
-#endif //CONFIG_ENCODERS
-
-static int url_read_packet(void *opaque, uint8_t *buf, int buf_size)
-{
-    URLContext *h = opaque;
-    return url_read(h, buf, buf_size);
-}
-
-static int url_seek_packet(void *opaque, int64_t offset, int whence)
-{
-    URLContext *h = opaque;
-    return url_seek(h, offset, whence);
-    //return 0;
+    do{
+        tmp = get_byte(bc);
+        val= (val<<7) + (tmp&127);
+    }while(tmp&128);
+    return val;
 }
 
-int url_fdopen(ByteIOContext *s, URLContext *h)
+int url_fdopen(ByteIOContext **s, URLContext *h)
 {
     uint8_t *buffer;
     int buffer_size, max_packet_size;
 
-    
     max_packet_size = url_get_max_packet_size(h);
     if (max_packet_size) {
         buffer_size = max_packet_size; /* no need to bufferize more than one packet */
@@ -512,41 +607,108 @@ int url_fdopen(ByteIOContext *s, URLContext *h)
     }
     buffer = av_malloc(buffer_size);
     if (!buffer)
-        return -ENOMEM;
+        return AVERROR(ENOMEM);
+
+    *s = av_mallocz(sizeof(ByteIOContext));
+    if(!*s) {
+        av_free(buffer);
+        return AVERROR(ENOMEM);
+    }
 
-    if (init_put_byte(s, buffer, buffer_size, 
+    if (init_put_byte(*s, buffer, buffer_size,
                       (h->flags & URL_WRONLY || h->flags & URL_RDWR), h,
-                      url_read_packet, url_write_packet, url_seek_packet) < 0) {
+                      url_read, url_write, url_seek) < 0) {
         av_free(buffer);
-        return AVERROR_IO;
+        av_freep(s);
+        return AVERROR(EIO);
+    }
+    (*s)->is_streamed = h->is_streamed;
+    (*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->is_streamed = h->is_streamed;
-    s->max_packet_size = max_packet_size;
     return 0;
 }
 
-/* XXX: must be called before any I/O */
 int url_setbufsize(ByteIOContext *s, int buf_size)
 {
     uint8_t *buffer;
     buffer = av_malloc(buf_size);
     if (!buffer)
-        return -ENOMEM;
+        return AVERROR(ENOMEM);
 
     av_free(s->buffer);
     s->buffer = buffer;
     s->buffer_size = buf_size;
     s->buf_ptr = buffer;
-    if (!s->write_flag) 
-        s->buf_end = buffer;
-    else
-        s->buf_end = buffer + buf_size;
+    url_resetbuf(s, s->write_flag ? URL_WRONLY : URL_RDONLY);
+    return 0;
+}
+
+#if FF_API_URL_RESETBUF
+int url_resetbuf(ByteIOContext *s, int flags)
+#else
+static int url_resetbuf(ByteIOContext *s, int flags)
+#endif
+{
+#if FF_API_URL_RESETBUF
+    if (flags & URL_RDWR)
+        return AVERROR(EINVAL);
+#else
+    assert(flags == URL_WRONLY || flags == URL_RDONLY);
+#endif
+
+    if (flags & URL_WRONLY) {
+        s->buf_end = s->buffer + s->buffer_size;
+        s->write_flag = 1;
+    } else {
+        s->buf_end = s->buffer;
+        s->write_flag = 0;
+    }
     return 0;
 }
 
-/* NOTE: when opened as read/write, the buffers are only used for
-   reading */
-int url_fopen(ByteIOContext *s, const char *filename, int flags)
+int ff_rewind_with_probe_data(ByteIOContext *s, unsigned char *buf, int buf_size)
+{
+    int64_t buffer_start;
+    int buffer_size;
+    int overlap, new_size, alloc_size;
+
+    if (s->write_flag)
+        return AVERROR(EINVAL);
+
+    buffer_size = s->buf_end - s->buffer;
+
+    /* the buffers must touch or overlap */
+    if ((buffer_start = s->pos - buffer_size) > buf_size)
+        return AVERROR(EINVAL);
+
+    overlap = buf_size - buffer_start;
+    new_size = buf_size + buffer_size - overlap;
+
+    alloc_size = FFMAX(s->buffer_size, new_size);
+    if (alloc_size > buf_size)
+        if (!(buf = av_realloc(buf, alloc_size)))
+            return AVERROR(ENOMEM);
+
+    if (new_size > buf_size) {
+        memcpy(buf + buf_size, s->buffer + overlap, buffer_size - overlap);
+        buf_size = new_size;
+    }
+
+    av_free(s->buffer);
+    s->buf_ptr = s->buffer = buf;
+    s->buffer_size = alloc_size;
+    s->pos = buf_size;
+    s->buf_end = s->buf_ptr + buf_size;
+    s->eof_reached = 0;
+    s->must_flush = 0;
+
+    return 0;
+}
+
+int url_fopen(ByteIOContext **s, const char *filename, int flags)
 {
     URLContext *h;
     int err;
@@ -565,9 +727,9 @@ int url_fopen(ByteIOContext *s, const char *filename, int flags)
 int url_fclose(ByteIOContext *s)
 {
     URLContext *h = s->opaque;
-    
+
     av_free(s->buffer);
-    memset(s, 0, sizeof(ByteIOContext));
+    av_free(s);
     return url_close(h);
 }
 
@@ -576,8 +738,7 @@ URLContext *url_fileno(ByteIOContext *s)
     return s->opaque;
 }
 
-#ifdef CONFIG_ENCODERS
-/* XXX: currently size is limited */
+#if CONFIG_MUXERS
 int url_fprintf(ByteIOContext *s, const char *fmt, ...)
 {
     va_list ap;
@@ -590,10 +751,8 @@ int url_fprintf(ByteIOContext *s, const char *fmt, ...)
     put_buffer(s, buf, strlen(buf));
     return ret;
 }
-#endif //CONFIG_ENCODERS
+#endif //CONFIG_MUXERS
 
-/* note: unlike fgets, the EOL character is not returned and a whole
-   line is parsed. return NULL if first char read was EOF */
 char *url_fgets(ByteIOContext *s, char *buf, int buf_size)
 {
     int c;
@@ -615,29 +774,56 @@ char *url_fgets(ByteIOContext *s, char *buf, int buf_size)
     return buf;
 }
 
-/* 
- * Return the maximum packet size associated to packetized buffered file
- * handle. If the file is not packetized (stream like http or file on
- * disk), then 0 is returned.
- * 
- * @param h buffered file handle
- * @return maximum packet size in bytes
- */
 int url_fget_max_packet_size(ByteIOContext *s)
 {
     return s->max_packet_size;
 }
 
-#ifdef CONFIG_ENCODERS
+int av_url_read_fpause(ByteIOContext *s, int pause)
+{
+    if (!s->read_pause)
+        return AVERROR(ENOSYS);
+    return s->read_pause(s->opaque, pause);
+}
+
+int64_t av_url_read_fseek(ByteIOContext *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) {
+        int64_t pos;
+        s->buf_ptr = s->buf_end; // Flush buffer
+        pos = s->seek(h, 0, SEEK_CUR);
+        if (pos >= 0)
+            s->pos = pos;
+        else if (pos != AVERROR(ENOSYS))
+            ret = pos;
+    }
+    return ret;
+}
+
+/* url_open_dyn_buf and url_close_dyn_buf are used in rtp.c to send a response
+ * back to the server even if CONFIG_MUXERS is false. */
+#if CONFIG_MUXERS || CONFIG_NETWORK
 /* buffer handling */
-int url_open_buf(ByteIOContext *s, uint8_t *buf, int buf_size, int flags)
+int url_open_buf(ByteIOContext **s, uint8_t *buf, int buf_size, int flags)
 {
-    return init_put_byte(s, buf, buf_size, 
-                         (flags & URL_WRONLY || flags & URL_RDWR),
-                         NULL, NULL, NULL, NULL);
+    int ret;
+    *s = av_mallocz(sizeof(ByteIOContext));
+    if(!*s)
+        return AVERROR(ENOMEM);
+    ret = init_put_byte(*s, buf, buf_size,
+                        (flags & URL_WRONLY || flags & URL_RDWR),
+                        NULL, NULL, NULL, NULL);
+    if(ret != 0)
+        av_freep(s);
+    return ret;
 }
 
-/* return the written or read size */
 int url_close_buf(ByteIOContext *s)
 {
     put_flush_packet(s);
@@ -656,8 +842,8 @@ typedef struct DynBuffer {
 static int dyn_buf_write(void *opaque, uint8_t *buf, int buf_size)
 {
     DynBuffer *d = opaque;
-    int new_size, new_allocated_size;
-    
+    unsigned new_size, new_allocated_size;
+
     /* reallocate buffer if needed */
     new_size = d->pos + buf_size;
     new_allocated_size = d->allocated_size;
@@ -667,13 +853,13 @@ static int dyn_buf_write(void *opaque, uint8_t *buf, int buf_size)
         if (!new_allocated_size)
             new_allocated_size = new_size;
         else
-            new_allocated_size += new_allocated_size / 2 + 1;    
+            new_allocated_size += new_allocated_size / 2 + 1;
     }
-    
+
     if (new_allocated_size > d->allocated_size) {
         d->buffer = av_realloc(d->buffer, new_allocated_size);
         if(d->buffer == NULL)
-             return -1234;
+             return AVERROR(ENOMEM);
         d->allocated_size = new_allocated_size;
     }
     memcpy(d->buffer + d->pos, buf, buf_size);
@@ -689,10 +875,7 @@ static int dyn_packet_buf_write(void *opaque, uint8_t *buf, int buf_size)
     int ret;
 
     /* packetized write: output the header */
-    buf1[0] = (buf_size >> 24);
-    buf1[1] = (buf_size >> 16);
-    buf1[2] = (buf_size >> 8);
-    buf1[3] = (buf_size);
+    AV_WB32(buf1, buf_size);
     ret= dyn_buf_write(opaque, buf1, 4);
     if(ret < 0)
         return ret;
@@ -701,7 +884,7 @@ static int dyn_packet_buf_write(void *opaque, uint8_t *buf, int buf_size)
     return dyn_buf_write(opaque, buf, buf_size);
 }
 
-static int dyn_buf_seek(void *opaque, offset_t offset, int whence)
+static int64_t dyn_buf_seek(void *opaque, int64_t offset, int whence)
 {
     DynBuffer *d = opaque;
 
@@ -715,80 +898,67 @@ static int dyn_buf_seek(void *opaque, offset_t offset, int whence)
     return 0;
 }
 
-static int url_open_dyn_buf_internal(ByteIOContext *s, int max_packet_size)
+static int url_open_dyn_buf_internal(ByteIOContext **s, int max_packet_size)
 {
     DynBuffer *d;
-    int io_buffer_size, ret;
-    
-    if (max_packet_size) 
-        io_buffer_size = max_packet_size;
-    else
-        io_buffer_size = 1024;
-        
+    int ret;
+    unsigned io_buffer_size = max_packet_size ? max_packet_size : 1024;
+
     if(sizeof(DynBuffer) + io_buffer_size < io_buffer_size)
         return -1;
-    d = av_malloc(sizeof(DynBuffer) + io_buffer_size);
+    d = av_mallocz(sizeof(DynBuffer) + io_buffer_size);
     if (!d)
-        return -1;
+        return AVERROR(ENOMEM);
+    *s = av_mallocz(sizeof(ByteIOContext));
+    if(!*s) {
+        av_free(d);
+        return AVERROR(ENOMEM);
+    }
     d->io_buffer_size = io_buffer_size;
-    d->buffer = NULL;
-    d->pos = 0;
-    d->size = 0;
-    d->allocated_size = 0;
-    ret = init_put_byte(s, d->io_buffer, io_buffer_size, 
-                        1, d, NULL, 
-                        max_packet_size ? dyn_packet_buf_write : dyn_buf_write, 
+    ret = init_put_byte(*s, d->io_buffer, io_buffer_size,
+                        1, d, NULL,
+                        max_packet_size ? dyn_packet_buf_write : dyn_buf_write,
                         max_packet_size ? NULL : dyn_buf_seek);
     if (ret == 0) {
-        s->max_packet_size = max_packet_size;
+        (*s)->max_packet_size = max_packet_size;
+    } else {
+        av_free(d);
+        av_freep(s);
     }
     return ret;
 }
 
-/*
- * Open a write only memory stream.
- * 
- * @param s new IO context
- * @return zero if no error.
- */
-int url_open_dyn_buf(ByteIOContext *s)
+int url_open_dyn_buf(ByteIOContext **s)
 {
     return url_open_dyn_buf_internal(s, 0);
 }
 
-/*
- * Open a write only packetized memory stream with a maximum packet
- * size of 'max_packet_size'.  The stream is stored in a memory buffer
- * with a big endian 4 byte header giving the packet size in bytes.
- * 
- * @param s new IO context
- * @param max_packet_size maximum packet size (must be > 0) 
- * @return zero if no error.
- */
-int url_open_dyn_packet_buf(ByteIOContext *s, int max_packet_size)
+int url_open_dyn_packet_buf(ByteIOContext **s, int max_packet_size)
 {
     if (max_packet_size <= 0)
         return -1;
     return url_open_dyn_buf_internal(s, max_packet_size);
 }
 
-/* 
- * Return the written size and a pointer to the buffer. The buffer
- *  must be freed with av_free(). 
- * @param s IO context
- * @param pointer to a byte buffer
- * @return the length of the byte buffer
- */
 int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer)
 {
     DynBuffer *d = s->opaque;
     int size;
+    static const char padbuf[FF_INPUT_BUFFER_PADDING_SIZE] = {0};
+    int padding = 0;
+
+    /* don't attempt to pad fixed-size packet buffers */
+    if (!s->max_packet_size) {
+        put_buffer(s, padbuf, sizeof(padbuf));
+        padding = FF_INPUT_BUFFER_PADDING_SIZE;
+    }
 
     put_flush_packet(s);
 
     *pbuffer = d->buffer;
     size = d->size;
     av_free(d);
-    return size;
+    av_free(s);
+    return size - padding;
 }
-#endif //CONFIG_ENCODERS
+#endif /* CONFIG_MUXERS || CONFIG_NETWORK */