/*

  * buffered I/O

  * Copyright (c) 2000,2001 Fabrice Bellard

  *

  * 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 2.1 of the License, or (at your option) any later version.

  *

  * 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 FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  */

 #include "libavutil/bprint.h"

 #include "libavutil/crc.h"

 #include "libavutil/dict.h"

 #include "libavutil/intreadwrite.h"

 #include "libavutil/log.h"
 #include "libavutil/opt.h"

 #include "libavutil/avassert.h"

 #include "avformat.h"

 #include "avio.h"

 #include "avio_internal.h"

 #include "internal.h"

 #include "url.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 *ff_avio_child_next(void *obj, void *prev)

 {
     AVIOContext *s = obj;
     return prev ? NULL : s->opaque;
 }
 

 static const AVClass *ff_avio_child_class_next(const AVClass *prev)

 {
     return prev ? NULL : &ffurl_context_class;
 }
 

 static const AVOption ff_avio_options[] = {

     { NULL },
 };
 

 const AVClass ff_avio_class = {

     .class_name = "AVIOContext",
     .item_name  = av_default_item_name,
     .version    = LIBAVUTIL_VERSION_INT,

     .option     = ff_avio_options,
     .child_next = ff_avio_child_next,
     .child_class_next = ff_avio_child_class_next,

 };

 static void fill_buffer(AVIOContext *s);
 static int url_resetbuf(AVIOContext *s, int flags);

 int ffio_init_context(AVIOContext *s,

                   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))

 {

     s->buffer      = buffer;

     s->orig_buffer_size =

     s->buffer_size = buffer_size;

     s->buf_ptr     = buffer;
     s->opaque      = opaque;

     s->direct      = 0;

     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        = seek ? AVIO_SEEKABLE_NORMAL : 0;

     s->max_packet_size = 0;

     s->update_checksum = NULL;

     s->short_seek_threshold = SHORT_SEEK_THRESHOLD;

 
     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;
 }

 AVIOContext *avio_alloc_context(

                   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))
 {

     AVIOContext *s = av_mallocz(sizeof(AVIOContext));

     if (!s)
         return NULL;

     ffio_init_context(s, buffer, buffer_size, write_flag, opaque,

                   read_packet, write_packet, seek);
     return s;
 }
 

 static void writeout(AVIOContext *s, const uint8_t *data, int len)
 {

     if (s->write_packet && !s->error) {
         int ret = s->write_packet(s->opaque, (uint8_t *)data, len);
         if (ret < 0) {

             s->error = ret;
         }
     }

     s->writeout_count ++;

     s->pos += len;
 }
 

 static void flush_buffer(AVIOContext *s)

 {

     if (s->write_flag && s->buf_ptr > s->buffer) {

         writeout(s, s->buffer, s->buf_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->buf_ptr = s->buffer;

     if (!s->write_flag)
         s->buf_end = s->buffer;

 }
 

 void avio_w8(AVIOContext *s, int b)

 {

     av_assert2(b>=-128 && b<=255);

     *s->buf_ptr++ = b;

     if (s->buf_ptr >= s->buf_end)

         flush_buffer(s);
 }
 

 void ffio_fill(AVIOContext *s, int b, int count)

 {
     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 avio_write(AVIOContext *s, const unsigned char *buf, int size)

 {

     if (s->direct && !s->update_checksum) {
         avio_flush(s);
         writeout(s, buf, size);
         return;
     }

     while (size > 0) {

         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)

             flush_buffer(s);
 
         buf += len;
         size -= len;
     }
 }
 

 void avio_flush(AVIOContext *s)

 {
     flush_buffer(s);
     s->must_flush = 0;
 }
 

 int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)

 {

     int64_t offset1;
     int64_t pos;

     int force = whence & AVSEEK_FORCE;

     int buffer_size;

     whence &= ~AVSEEK_FORCE;

 
     if(!s)
         return AVERROR(EINVAL);
 

     buffer_size = s->buf_end - s->buffer;
     pos = s->pos - (s->write_flag ? 0 : buffer_size);

 
     if (whence != SEEK_CUR && whence != SEEK_SET)

         return AVERROR(EINVAL);

     if (whence == SEEK_CUR) {
         offset1 = pos + (s->buf_ptr - s->buffer);
         if (offset == 0)
             return offset1;
         offset += offset1;
     }

     if (offset < 0)
         return AVERROR(EINVAL);
 

     offset1 = offset - pos;

     if (!s->must_flush && (!s->direct || !s->seek) &&

         offset1 >= 0 && offset1 <= buffer_size - s->write_flag) {

         /* can do the seek inside the buffer */
         s->buf_ptr = s->buffer + offset1;

     } else if ((!s->seekable ||

                offset1 <= s->buf_end + s->short_seek_threshold - s->buffer) &&

                !s->write_flag && offset1 >= 0 &&

                (!s->direct || !s->seek) &&

               (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 if(!s->write_flag && offset1 < 0 && -offset1 < buffer_size>>1 && s->seek && offset > 0) {

         int64_t res;

         pos -= FFMIN(buffer_size>>1, pos);
         if ((res = s->seek(s->opaque, pos, SEEK_SET)) < 0)
             return res;
         s->buf_end =
         s->buf_ptr = s->buffer;
         s->pos = pos;
         s->eof_reached = 0;
         fill_buffer(s);
         return avio_seek(s, offset, SEEK_SET | force);
     } else {
         int64_t res;

         if (s->write_flag) {

             flush_buffer(s);
             s->must_flush = 1;
         }

         if (!s->seek)
             return AVERROR(EPIPE);
         if ((res = s->seek(s->opaque, offset, SEEK_SET)) < 0)

             return res;

         s->seek_count ++;

         if (!s->write_flag)
             s->buf_end = s->buffer;
         s->buf_ptr = s->buffer;

         s->pos = offset;

     }

     s->eof_reached = 0;

     return offset;
 }
 

 int64_t avio_skip(AVIOContext *s, int64_t offset)
 {
     return avio_seek(s, offset, SEEK_CUR);
 }
 

 int64_t avio_size(AVIOContext *s)

 {

     int64_t size;

     if (!s)

         return AVERROR(EINVAL);
 

     if (!s->seek)

         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 avio_feof(AVIOContext *s)

 {

     if(!s)
         return 0;

     if(s->eof_reached){
         s->eof_reached=0;
         fill_buffer(s);
     }

     return s->eof_reached;
 }
 

 #if FF_API_URL_FEOF
 int url_feof(AVIOContext *s)
 {
     return avio_feof(s);
 }
 #endif
 

 void avio_wl32(AVIOContext *s, unsigned int val)

 {

     avio_w8(s, (uint8_t) val       );
     avio_w8(s, (uint8_t)(val >> 8 ));
     avio_w8(s, (uint8_t)(val >> 16));
     avio_w8(s,           val >> 24 );

 }
 

 void avio_wb32(AVIOContext *s, unsigned int val)

 {

     avio_w8(s,           val >> 24 );
     avio_w8(s, (uint8_t)(val >> 16));
     avio_w8(s, (uint8_t)(val >> 8 ));
     avio_w8(s, (uint8_t) val       );

 }
 

 int avio_put_str(AVIOContext *s, const char *str)

 {
     int len = 1;
     if (str) {
         len += strlen(str);

         avio_write(s, (const unsigned char *) str, len);

     } else

         avio_w8(s, 0);

     return len;

 }
 

 static inline int put_str16(AVIOContext *s, const char *str, const int be)

 {
     const uint8_t *q = str;
     int ret = 0;

     int err = 0;

 
     while (*q) {
         uint32_t ch;
         uint16_t tmp;
 

         GET_UTF8(ch, *q++, goto invalid;)

         PUT_UTF16(ch, tmp, be ? avio_wb16(s, tmp) : avio_wl16(s, tmp);
                   ret += 2;)

         continue;
 invalid:

         av_log(s, AV_LOG_ERROR, "Invaid UTF8 sequence in avio_put_str16%s\n", be ? "be" : "le");

         err = AVERROR(EINVAL);

     }

     if (be)
         avio_wb16(s, 0);
     else
         avio_wl16(s, 0);

     if (err)
         return err;

     ret += 2;
     return ret;
 }
 

 #define PUT_STR16(type, big_endian)                          \
 int avio_put_str16 ## type(AVIOContext *s, const char *str)  \
 {                                                            \
 return put_str16(s, str, big_endian);                        \
 }
 
 PUT_STR16(le, 0)
 PUT_STR16(be, 1)
 
 #undef PUT_STR16
 

 int ff_get_v_length(uint64_t val)
 {
     int i = 1;

     while (val >>= 7)

         i++;
 
     return i;
 }
 

 void ff_put_v(AVIOContext *bc, uint64_t val)
 {
     int i = ff_get_v_length(val);

     while (--i > 0)

         avio_w8(bc, 128 | (uint8_t)(val >> (7*i)));

     avio_w8(bc, val & 127);

 }
 

 void avio_wl64(AVIOContext *s, uint64_t val)

 {

     avio_wl32(s, (uint32_t)(val & 0xffffffff));
     avio_wl32(s, (uint32_t)(val >> 32));

 }
 

 void avio_wb64(AVIOContext *s, uint64_t val)

 {

     avio_wb32(s, (uint32_t)(val >> 32));
     avio_wb32(s, (uint32_t)(val & 0xffffffff));

 }
 

 void avio_wl16(AVIOContext *s, unsigned int val)

 {

     avio_w8(s, (uint8_t)val);
     avio_w8(s, (int)val >> 8);

 }
 

 void avio_wb16(AVIOContext *s, unsigned int val)

 {

     avio_w8(s, (int)val >> 8);
     avio_w8(s, (uint8_t)val);

 }
 

 void avio_wl24(AVIOContext *s, unsigned int val)

 {

     avio_wl16(s, val & 0xffff);

     avio_w8(s, (int)val >> 16);

 }
 

 void avio_wb24(AVIOContext *s, unsigned int val)

 {

     avio_wb16(s, (int)val >> 8);
     avio_w8(s, (uint8_t)val);

 }
 

 /* Input stream */
 

 static void fill_buffer(AVIOContext *s)

 {

     int max_buffer_size = s->max_packet_size ?
                           s->max_packet_size : IO_BUFFER_SIZE;

     uint8_t *dst        = s->buf_end - s->buffer + max_buffer_size < s->buffer_size ?
                           s->buf_end : s->buffer;
     int len             = s->buffer_size - (dst - s->buffer);

     /* 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;
 

     /* no need to do anything if EOF already reached */
     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;

     }
 

     /* make buffer smaller in case it ended up large after probing */

     if (s->read_packet && s->orig_buffer_size && s->buffer_size > s->orig_buffer_size) {

         if (dst == s->buffer) {

             int ret = ffio_set_buf_size(s, s->orig_buffer_size);
             if (ret < 0)
                 av_log(s, AV_LOG_WARNING, "Failed to decrease buffer size\n");

             s->checksum_ptr = dst = s->buffer;
         }

         av_assert0(len >= s->orig_buffer_size);
         len = s->orig_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;

     } else {
         s->pos += len;

         s->buf_ptr = dst;
         s->buf_end = dst + len;

         s->bytes_read += len;

     }
 }
 

 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 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;

     return s->checksum;
 }
 

 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;

     }

 }
 

 /* XXX: put an inline version */

 int avio_r8(AVIOContext *s)

 {

     if (s->buf_ptr >= s->buf_end)

         fill_buffer(s);

     if (s->buf_ptr < s->buf_end)
         return *s->buf_ptr++;
     return 0;

 }
 

 int avio_read(AVIOContext *s, unsigned char *buf, int size)

 {
     int len, size1;
 
     size1 = size;
     while (size > 0) {
         len = s->buf_end - s->buf_ptr;
         if (len > size)
             len = size;

         if (len == 0 || s->write_flag) {

             if((s->direct || size > s->buffer_size) && !s->update_checksum){

                 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 */
                     s->eof_reached = 1;
                     if(len<0)
                         s->error= len;
                     break;
                 } else {
                     s->pos += len;

                     s->bytes_read += len;

                     size -= len;
                     buf += len;
                     s->buf_ptr = s->buffer;
                     s->buf_end = s->buffer/* + len*/;
                 }

             } else {

                 fill_buffer(s);
                 len = s->buf_end - s->buf_ptr;
                 if (len == 0)
                     break;
             }

         } else {
             memcpy(buf, s->buf_ptr, len);
             buf += len;
             s->buf_ptr += len;
             size -= len;
         }
     }

     if (size1 == size) {

         if (s->error)      return s->error;

         if (avio_feof(s))  return AVERROR_EOF;

     }

     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)

         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;
     }
     if (len > size)
         len = size;
     memcpy(buf, s->buf_ptr, len);
     s->buf_ptr += len;

     if (!len) {

         if (s->error)      return s->error;

         if (avio_feof(s))  return AVERROR_EOF;

     }

     return len;
 }
 

 unsigned int avio_rl16(AVIOContext *s)

 {
     unsigned int val;

     val = avio_r8(s);
     val |= avio_r8(s) << 8;

     return val;
 }
 

 unsigned int avio_rl24(AVIOContext *s)

 {
     unsigned int val;

     val = avio_rl16(s);
     val |= avio_r8(s) << 16;

     return val;
 }
 

 unsigned int avio_rl32(AVIOContext *s)

 {
     unsigned int val;

     val = avio_rl16(s);
     val |= avio_rl16(s) << 16;

     return val;
 }
 

 uint64_t avio_rl64(AVIOContext *s)

 {

     uint64_t val;

     val = (uint64_t)avio_rl32(s);
     val |= (uint64_t)avio_rl32(s) << 32;

     return val;
 }
 

 unsigned int avio_rb16(AVIOContext *s)

 {
     unsigned int val;

     val = avio_r8(s) << 8;
     val |= avio_r8(s);

     return val;
 }
 

 unsigned int avio_rb24(AVIOContext *s)

 {
     unsigned int val;

     val = avio_rb16(s) << 8;
     val |= avio_r8(s);

     return val;
 }

 unsigned int avio_rb32(AVIOContext *s)

 {
     unsigned int val;

     val = avio_rb16(s) << 16;
     val |= avio_rb16(s);

     return val;
 }

 int ff_get_line(AVIOContext *s, char *buf, int maxlen)

 {
     int i = 0;
     char c;
 
     do {

         c = avio_r8(s);

         if (c && i < maxlen-1)

             buf[i++] = c;

     } while (c != '\n' && c != '\r' && c);

     if (c == '\r' && avio_r8(s) != '\n' && !avio_feof(s))

         avio_skip(s, -1);

 
     buf[i] = 0;

     return i;

 }
 

 int avio_get_str(AVIOContext *s, int maxlen, char *buf, int buflen)
 {
     int i;
 

     if (buflen <= 0)
         return AVERROR(EINVAL);

     // reserve 1 byte for terminating 0
     buflen = FFMIN(buflen - 1, maxlen);
     for (i = 0; i < buflen; i++)
         if (!(buf[i] = avio_r8(s)))
             return i + 1;

     buf[i] = 0;

     for (; i < maxlen; i++)
         if (!avio_r8(s))
             return i + 1;
     return maxlen;
 }
 

 #define GET_STR16(type, read) \

     int avio_get_str16 ##type(AVIOContext *pb, int maxlen, char *buf, int buflen)\

 {\
     char* q = buf;\
     int ret = 0;\

     if (buflen <= 0) \
         return AVERROR(EINVAL); \

     while (ret + 1 < maxlen) {\
         uint8_t tmp;\
         uint32_t ch;\
         GET_UTF16(ch, (ret += 2) <= maxlen ? read(pb) : 0, break;)\
         if (!ch)\
             break;\
         PUT_UTF8(ch, tmp, if (q - buf < buflen - 1) *q++ = tmp;)\
     }\
     *q = 0;\
     return ret;\
 }\
 

 GET_STR16(le, avio_rl16)
 GET_STR16(be, avio_rb16)

 
 #undef GET_STR16
 

 uint64_t avio_rb64(AVIOContext *s)

 {

     uint64_t val;

     val = (uint64_t)avio_rb32(s) << 32;
     val |= (uint64_t)avio_rb32(s);

     return val;
 }
 

 uint64_t ffio_read_varlen(AVIOContext *bc){

     uint64_t val = 0;
     int tmp;
 
     do{

         tmp = avio_r8(bc);

         val= (val<<7) + (tmp&127);
     }while(tmp&128);
     return val;
 }
 

 int ffio_fdopen(AVIOContext **s, URLContext *h)

 {

     uint8_t *buffer;

     int buffer_size, max_packet_size;

     max_packet_size = h->max_packet_size;

     if (max_packet_size) {
         buffer_size = max_packet_size; /* no need to bufferize more than one packet */
     } else {
         buffer_size = IO_BUFFER_SIZE;
     }

     buffer = av_malloc(buffer_size);

     if (!buffer)

         return AVERROR(ENOMEM);

     *s = avio_alloc_context(buffer, buffer_size, h->flags & AVIO_FLAG_WRITE, h,

                             (int (*)(void *, uint8_t *, int)) ffurl_read,
                             (int (*)(void *, uint8_t *, int)) ffurl_write,
                             (int64_t (*)(void *, int64_t, int)) ffurl_seek);

     if (!*s) {

         av_free(buffer);
         return AVERROR(ENOMEM);
     }

     (*s)->direct = h->flags & AVIO_FLAG_DIRECT;

     (*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)->av_class = &ff_avio_class;

     return 0;
 }
 

 int ffio_ensure_seekback(AVIOContext *s, int64_t buf_size)

 {
     uint8_t *buffer;
     int max_buffer_size = s->max_packet_size ?
                           s->max_packet_size : IO_BUFFER_SIZE;

     int filled = s->buf_end - s->buffer;

     ptrdiff_t checksum_ptr_offset = s->checksum_ptr ? s->checksum_ptr - s->buffer : -1;

 
     buf_size += s->buf_ptr - s->buffer + max_buffer_size;
 

     if (buf_size < filled || s->seekable || !s->read_packet)

         return 0;
     av_assert0(!s->write_flag);
 
     buffer = av_malloc(buf_size);
     if (!buffer)
         return AVERROR(ENOMEM);
 

     memcpy(buffer, s->buffer, filled);

     av_free(s->buffer);
     s->buf_ptr = buffer + (s->buf_ptr - s->buffer);
     s->buf_end = buffer + (s->buf_end - s->buffer);
     s->buffer = buffer;
     s->buffer_size = buf_size;

     if (checksum_ptr_offset >= 0)
         s->checksum_ptr = s->buffer + checksum_ptr_offset;

     return 0;
 }
 

 int ffio_set_buf_size(AVIOContext *s, int buf_size)

 {

     uint8_t *buffer;

     buffer = av_malloc(buf_size);

     if (!buffer)

         return AVERROR(ENOMEM);

     av_free(s->buffer);

     s->buffer = buffer;

     s->orig_buffer_size =

     s->buffer_size = buf_size;
     s->buf_ptr = buffer;

     url_resetbuf(s, s->write_flag ? AVIO_FLAG_WRITE : AVIO_FLAG_READ);

     return 0;
 }
 

 static int url_resetbuf(AVIOContext *s, int flags)

 {

     av_assert1(flags == AVIO_FLAG_WRITE || flags == AVIO_FLAG_READ);

     if (flags & AVIO_FLAG_WRITE) {

         s->buf_end = s->buffer + s->buffer_size;
         s->write_flag = 1;
     } else {
         s->buf_end = s->buffer;
         s->write_flag = 0;
     }

     return 0;
 }
 

 int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char **bufp, int buf_size)

 {
     int64_t buffer_start;
     int buffer_size;

     int overlap, new_size, alloc_size;

     uint8_t *buf = *bufp;

     if (s->write_flag) {
         av_freep(bufp);

         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) {
         av_freep(bufp);

         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 = (*bufp) = av_realloc_f(buf, 1, 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 avio_open(AVIOContext **s, const char *filename, int flags)

 {

     return avio_open2(s, filename, flags, NULL, NULL);
 }
 
 int avio_open2(AVIOContext **s, const char *filename, int flags,
                const AVIOInterruptCB *int_cb, AVDictionary **options)
 {

     URLContext *h;
     int err;
 

     err = ffurl_open(&h, filename, flags, int_cb, options);

     if (err < 0)
         return err;

     err = ffio_fdopen(s, h);

     if (err < 0) {

         ffurl_close(h);

         return err;
     }
     return 0;
 }
 

 int ffio_open2_wrapper(struct AVFormatContext *s, AVIOContext **pb, const char *url, int flags,
                        const AVIOInterruptCB *int_cb, AVDictionary **options)
 {
     return avio_open2(pb, url, flags, int_cb, options);
 }
 

 int avio_close(AVIOContext *s)

 {

     URLContext *h;
 
     if (!s)
         return 0;

     avio_flush(s);

     h = s->opaque;

     av_freep(&s->buffer);

     if (s->write_flag)
         av_log(s, AV_LOG_DEBUG, "Statistics: %d seeks, %d writeouts\n", s->seek_count, s->writeout_count);
     else

         av_log(s, AV_LOG_DEBUG, "Statistics: %"PRId64" bytes read, %d seeks\n", s->bytes_read, s->seek_count);

     av_free(s);

     return ffurl_close(h);

 }
 

 int avio_closep(AVIOContext **s)
 {
     int ret = avio_close(*s);
     *s = NULL;
     return ret;
 }
 

 int avio_printf(AVIOContext *s, const char *fmt, ...)

 {
     va_list ap;
     char buf[4096];
     int ret;
 
     va_start(ap, fmt);
     ret = vsnprintf(buf, sizeof(buf), fmt, ap);
     va_end(ap);

     avio_write(s, buf, strlen(buf));

     return ret;
 }
 

 int avio_pause(AVIOContext *s, int pause)

 {
     if (!s->read_pause)
         return AVERROR(ENOSYS);

     return s->read_pause(s->opaque, 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) {

         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;
 }
 

 int avio_read_to_bprint(AVIOContext *h, AVBPrint *pb, size_t max_size)
 {
     int ret;
     char buf[1024];
     while (max_size) {
         ret = avio_read(h, buf, FFMIN(max_size, sizeof(buf)));
         if (ret == AVERROR_EOF)
             return 0;
         if (ret <= 0)
             return ret;
         av_bprint_append_data(pb, buf, ret);
         if (!av_bprint_is_complete(pb))
             return AVERROR(ENOMEM);
         max_size -= ret;
     }
     return 0;
 }
 

 int avio_accept(AVIOContext *s, AVIOContext **c)
 {
     int ret;
     URLContext *sc = s->opaque;
     URLContext *cc = NULL;
     ret = ffurl_accept(sc, &cc);
     if (ret < 0)
         return ret;
     return ffio_fdopen(c, cc);
 }
 
 int avio_handshake(AVIOContext *c)
 {
     URLContext *cc = c->opaque;
     return ffurl_handshake(cc);
 }
 

 /* output in a dynamic buffer */
 
 typedef struct DynBuffer {
     int pos, size, allocated_size;

     uint8_t *buffer;

     int io_buffer_size;

     uint8_t io_buffer[1];

 } DynBuffer;
 

 static int dyn_buf_write(void *opaque, uint8_t *buf, int buf_size)

 {
     DynBuffer *d = opaque;

     unsigned new_size, new_allocated_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)

         return -1;

     while (new_size > new_allocated_size) {
         if (!new_allocated_size)
             new_allocated_size = new_size;
         else

             new_allocated_size += new_allocated_size / 2 + 1;

     }

     if (new_allocated_size > d->allocated_size) {

         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);
     d->pos = new_size;
     if (d->pos > d->size)
         d->size = d->pos;

     return buf_size;

 }
 

 static int dyn_packet_buf_write(void *opaque, uint8_t *buf, int buf_size)

 {
     unsigned char buf1[4];

     int ret;

 
     /* packetized write: output the header */

     AV_WB32(buf1, buf_size);

     ret = dyn_buf_write(opaque, buf1, 4);
     if (ret < 0)

         return ret;

 
     /* then the data */

     return dyn_buf_write(opaque, buf, buf_size);

 }
 

 static int64_t dyn_buf_seek(void *opaque, int64_t offset, int whence)

 {
     DynBuffer *d = opaque;
 
     if (whence == SEEK_CUR)
         offset += d->pos;
     else if (whence == SEEK_END)
         offset += d->size;
     if (offset < 0 || offset > 0x7fffffffLL)
         return -1;
     d->pos = offset;
     return 0;
 }
 

 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)

         return -1;

     d = av_mallocz(sizeof(DynBuffer) + io_buffer_size);

     if (!d)

         return AVERROR(ENOMEM);

     d->io_buffer_size = io_buffer_size;
     *s = avio_alloc_context(d->io_buffer, d->io_buffer_size, 1, d, NULL,
                             max_packet_size ? dyn_packet_buf_write : dyn_buf_write,
                             max_packet_size ? NULL : dyn_buf_seek);

     if(!*s) {
         av_free(d);
         return AVERROR(ENOMEM);
     }

     (*s)->max_packet_size = max_packet_size;
     return 0;

 }
 

 int avio_open_dyn_buf(AVIOContext **s)

 {
     return url_open_dyn_buf_internal(s, 0);
 }
 

 int ffio_open_dyn_packet_buf(AVIOContext **s, int max_packet_size)

 {
     if (max_packet_size <= 0)
         return -1;
     return url_open_dyn_buf_internal(s, max_packet_size);
 }
 

 int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer)

 {

     DynBuffer *d;

     int size;

     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 = 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;
 }