text: /*
   * Buffered I/O for ffmpeg system
   * 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 "avformat.h"
  #include "avio.h"
  #include <stdarg.h>
  
  #define IO_BUFFER_SIZE 32768
  
  static void fill_buffer(ByteIOContext *s);
  
  int init_put_byte(ByteIOContext *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),
                    offset_t (*seek)(void *opaque, offset_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;
      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->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;
      }
      return 0;
  }
  
  static void flush_buffer(ByteIOContext *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){
                  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;
          }
          s->pos += s->buf_ptr - s->buffer;
      }
      s->buf_ptr = s->buffer;
  }
  
  void put_byte(ByteIOContext *s, int b)
  {
      *(s->buf_ptr)++ = b;
      if (s->buf_ptr >= s->buf_end)
          flush_buffer(s);
  }
  
  void put_buffer(ByteIOContext *s, const unsigned char *buf, int size)
  {
      int len;
  
      while (size > 0) {
          len = (s->buf_end - s->buf_ptr);
          if (len > size)
              len = 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 put_flush_packet(ByteIOContext *s)
  {
      flush_buffer(s);
      s->must_flush = 0;
  }
  
  offset_t url_fseek(ByteIOContext *s, offset_t offset, int whence)
  {
      offset_t offset1;
      offset_t pos= s->pos - (s->write_flag ? 0 : (s->buf_end - s->buffer));
  
      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;
      }
      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 && !s->write_flag &&
                offset1 >= 0 && offset1 < (s->buf_end - s->buffer) + (1<<16)){
          while(s->pos < offset && !s->eof_reached)
              fill_buffer(s);
          s->buf_ptr = s->buf_end + offset - s->pos;
      } else {
          offset_t res = AVERROR(EPIPE);
  
  #if defined(CONFIG_MUXERS) || defined(CONFIG_NETWORK)
          if (s->write_flag) {
              flush_buffer(s);
              s->must_flush = 1;
          } else
  #endif /* defined(CONFIG_MUXERS) || defined(CONFIG_NETWORK) */
          {
              s->buf_end = s->buffer;
          }
          s->buf_ptr = s->buffer;
          if (!s->seek || (res = s->seek(s->opaque, offset, SEEK_SET)) < 0)
              return res;
          s->pos = offset;
      }
      s->eof_reached = 0;
      return offset;
  }
  
  void url_fskip(ByteIOContext *s, offset_t offset)
  {
      url_fseek(s, offset, SEEK_CUR);
  }
  
  offset_t url_ftell(ByteIOContext *s)
  {
      return url_fseek(s, 0, SEEK_CUR);
  }
  
  offset_t url_fsize(ByteIOContext *s)
  {
      offset_t size;
  
      if (!s->seek)
          return AVERROR(EPIPE);
      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)
  {
      return s->eof_reached;
  }
  
  int url_ferror(ByteIOContext *s)
  {
      return s->error;
  }
  
  void put_le32(ByteIOContext *s, unsigned int val)
  {
      put_byte(s, val);
      put_byte(s, val >> 8);
      put_byte(s, val >> 16);
      put_byte(s, val >> 24);
  }
  
  void put_be32(ByteIOContext *s, unsigned int val)
  {
      put_byte(s, val >> 24);
      put_byte(s, val >> 16);
      put_byte(s, val >> 8);
      put_byte(s, val);
  }
  
  void put_strz(ByteIOContext *s, const char *str)
  {
      if (str)
          put_buffer(s, (const unsigned char *) str, strlen(str) + 1);
      else
          put_byte(s, 0);
  }
  
  void put_le64(ByteIOContext *s, uint64_t val)
  {
      put_le32(s, (uint32_t)(val & 0xffffffff));
      put_le32(s, (uint32_t)(val >> 32));
  }
  
  void put_be64(ByteIOContext *s, uint64_t val)
  {
      put_be32(s, (uint32_t)(val >> 32));
      put_be32(s, (uint32_t)(val & 0xffffffff));
  }
  
  void put_le16(ByteIOContext *s, unsigned int val)
  {
      put_byte(s, val);
      put_byte(s, val >> 8);
  }
  
  void put_be16(ByteIOContext *s, unsigned int val)
  {
      put_byte(s, val >> 8);
      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++);
      }
  }
  
  /* Input stream */
  
  static void fill_buffer(ByteIOContext *s)
  {
      int len;
  
      /* no need to do anything if EOF already reached */
      if (s->eof_reached)
          return;
  
      if(s->update_checksum){
          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);
      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 = s->buffer;
          s->buf_end = s->buffer + 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){
      s->update_checksum= update_checksum;
      if(s->update_checksum){
          s->checksum= checksum;
          s->checksum_ptr= s->buf_ptr;
      }
  }
  
  /* XXX: put an inline version */
  int get_byte(ByteIOContext *s)
  {
      if (s->buf_ptr < s->buf_end) {
          return *s->buf_ptr++;
      } else {
          fill_buffer(s);
          if (s->buf_ptr < s->buf_end)
              return *s->buf_ptr++;
          else
              return 0;
      }
  }
  
  int url_fgetc(ByteIOContext *s)
  {
      if (s->buf_ptr < s->buf_end) {
          return *s->buf_ptr++;
      } else {
          fill_buffer(s);
          if (s->buf_ptr < s->buf_end)
              return *s->buf_ptr++;
          else
              return URL_EOF;
      }
  }
  
  int get_buffer(ByteIOContext *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) {
              if(size > s->buffer_size && !s->update_checksum){
                  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;
                      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 {
              av_memcpy(buf, s->buf_ptr, len);
              buf += len;
              s->buf_ptr += len;
              size -= len;
          }
      }
      return size1 - size;
  }
  
  int get_partial_buffer(ByteIOContext *s, unsigned char *buf, int size)
  {
      int len;
  
      if(size<0)
          return -1;
  
      len = s->buf_end - s->buf_ptr;
      if (len == 0) {
          fill_buffer(s);
          len = s->buf_end - s->buf_ptr;
      }
      if (len > size)
          len = size;
      av_memcpy(buf, s->buf_ptr, len);
      s->buf_ptr += len;
      return len;
  }
  
  unsigned int get_le16(ByteIOContext *s)
  {
      unsigned int val;
      val = get_byte(s);
      val |= get_byte(s) << 8;
      return val;
  }
  
  unsigned int get_le24(ByteIOContext *s)
  {
      unsigned int val;
      val = get_le16(s);
      val |= get_byte(s) << 16;
      return val;
  }
  
  unsigned int get_le32(ByteIOContext *s)
  {
      unsigned int val;
      val = get_le16(s);
      val |= get_le16(s) << 16;
      return val;
  }
  
  uint64_t get_le64(ByteIOContext *s)
  {
      uint64_t val;
      val = (uint64_t)get_le32(s);
      val |= (uint64_t)get_le32(s) << 32;
      return val;
  }
  
  unsigned int get_be16(ByteIOContext *s)
  {
      unsigned int val;
      val = get_byte(s) << 8;
      val |= get_byte(s);
      return val;
  }
  
  unsigned int get_be24(ByteIOContext *s)
  {
      unsigned int val;
      val = get_be16(s) << 8;
      val |= get_byte(s);
      return val;
  }
  unsigned int get_be32(ByteIOContext *s)
  {
      unsigned int val;
      val = get_be16(s) << 16;
      val |= get_be16(s);
      return val;
  }
  
  char *get_strz(ByteIOContext *s, char *buf, int maxlen)
  {
      int i = 0;
      char c;
  
      while ((c = get_byte(s))) {
          if (i < maxlen-1)
              buf[i++] = c;
      }
  
      buf[i] = 0; /* Ensure null terminated, but may be truncated */
  
      return buf;
  }
  
  uint64_t get_be64(ByteIOContext *s)
  {
      uint64_t val;
      val = (uint64_t)get_be32(s) << 32;
      val |= (uint64_t)get_be32(s);
      return val;
  }
  
  /* link with avio functions */
  
  #ifdef CONFIG_MUXERS
  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_MUXERS
  
  static int url_read_packet(void *opaque, uint8_t *buf, int buf_size)
  {
      URLContext *h = opaque;
      return url_read(h, buf, buf_size);
  }
  
  static offset_t url_seek_packet(void *opaque, offset_t offset, int whence)
  {
      URLContext *h = opaque;
      return url_seek(h, offset, whence);
      //return 0;
  }
  
  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 */
      } else {
          buffer_size = IO_BUFFER_SIZE;
      }
      buffer = av_mallocUncached(buffer_size);
      if (!buffer)
          return AVERROR(ENOMEM);
  
      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) {
          av_free(buffer);
          return AVERROR_IO;
      }
      s->is_streamed = h->is_streamed;
      s->max_packet_size = max_packet_size;
      return 0;
  }
  
  int url_setbufsize(ByteIOContext *s, int buf_size)
  {
      uint8_t *buffer;
      buffer = av_mallocUncached(buf_size);
      if (!buffer)
          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;
      return 0;
  }
  
  int url_fopen(ByteIOContext *s, const char *filename, int flags)
  {
      URLContext *h;
      int err;
  
      err = url_open(&h, filename, flags);
      if (err < 0)
          return err;
      err = url_fdopen(s, h);
      if (err < 0) {
          url_close(h);
          return err;
      }
      return 0;
  }
  
  int url_fclose(ByteIOContext *s)
  {
      URLContext *h = s->opaque;
  
      av_free(s->buffer);
      memset(s, 0, sizeof(ByteIOContext));
      return url_close(h);
  }
  
  URLContext *url_fileno(ByteIOContext *s)
  {
      return s->opaque;
  }
  
  #ifdef CONFIG_MUXERS
  int url_fprintf(ByteIOContext *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);
      put_buffer(s, buf, strlen(buf));
      return ret;
  }
  #endif //CONFIG_MUXERS
  
  char *url_fgets(ByteIOContext *s, char *buf, int buf_size)
  {
      int c;
      char *q;
  
      c = url_fgetc(s);
      if (c == EOF)
          return NULL;
      q = buf;
      for(;;) {
          if (c == EOF || c == '\n')
              break;
          if ((q - buf) < buf_size - 1)
              *q++ = c;
          c = url_fgetc(s);
      }
      if (buf_size > 0)
          *q = '\0';
      return buf;
  }
  
  int url_fget_max_packet_size(ByteIOContext *s)
  {
      return s->max_packet_size;
  }
  
  /* 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 not set. */
  #if defined(CONFIG_MUXERS) || defined(CONFIG_NETWORK)
  /* buffer handling */
  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 url_close_buf(ByteIOContext *s)
  {
      put_flush_packet(s);
      return s->buf_ptr - s->buffer;
  }
  
  /* 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;
      int 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) {
          d->buffer = av_realloc(d->buffer, new_allocated_size);
          if(d->buffer == NULL)
               return -1234;
          d->allocated_size = new_allocated_size;
      }
      av_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 */
      buf1[0] = (buf_size >> 24);
      buf1[1] = (buf_size >> 16);
      buf1[2] = (buf_size >> 8);
      buf1[3] = (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 offset_t dyn_buf_seek(void *opaque, offset_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(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;
  
      if(sizeof(DynBuffer) + io_buffer_size < io_buffer_size)
          return -1;
      d = av_malloc(sizeof(DynBuffer) + io_buffer_size);
      if (!d)
          return -1;
      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,
                          max_packet_size ? NULL : dyn_buf_seek);
      if (ret == 0) {
          s->max_packet_size = max_packet_size;
      }
      return ret;
  }
  
  int url_open_dyn_buf(ByteIOContext *s)
  {
      return url_open_dyn_buf_internal(s, 0);
  }
  
  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);
  }
  
  int url_close_dyn_buf(ByteIOContext *s, uint8_t **pbuffer)
  {
      DynBuffer *d = s->opaque;
      int size;
  
      put_flush_packet(s);
  
      *pbuffer = d->buffer;
      size = d->size;
      av_free(d);
      return size;
  }
  #endif /* CONFIG_MUXERS || CONFIG_NETWORK */
  