text: /*
   * HTTP protocol for ffmpeg client
   * 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 "config.h"
  
  #if CONFIG_ZLIB
  #include <zlib.h>
  #endif /* CONFIG_ZLIB */
  
  #include "libavutil/avassert.h"
  #include "libavutil/avstring.h"
  #include "libavutil/opt.h"
  #include "libavutil/time.h"
  #include "libavutil/parseutils.h"
  
  #include "avformat.h"
  #include "http.h"
  #include "httpauth.h"
  #include "internal.h"
  #include "network.h"
  #include "os_support.h"
  #include "url.h"
  
  /* XXX: POST protocol is not completely implemented because ffmpeg uses
   * only a subset of it. */
  
  /* The IO buffer size is unrelated to the max URL size in itself, but needs
   * to be large enough to fit the full request headers (including long
   * path names). */
  #define BUFFER_SIZE   MAX_URL_SIZE
  #define MAX_REDIRECTS 8
  #define HTTP_SINGLE   1
  #define HTTP_MUTLI    2
  #define MAX_EXPIRY    19
  #define WHITESPACES " \n\t\r"
  typedef enum {
      LOWER_PROTO,
      READ_HEADERS,
      WRITE_REPLY_HEADERS,
      FINISH
  }HandshakeState;
  
  typedef struct HTTPContext {
      const AVClass *class;
      URLContext *hd;
      unsigned char buffer[BUFFER_SIZE], *buf_ptr, *buf_end;
      int line_count;
      int http_code;
      /* Used if "Transfer-Encoding: chunked" otherwise -1. */
      uint64_t chunksize;
      uint64_t off, end_off, filesize;
      char *location;
      HTTPAuthState auth_state;
      HTTPAuthState proxy_auth_state;
      char *http_proxy;
      char *headers;
      char *mime_type;
      char *user_agent;
  #if FF_API_HTTP_USER_AGENT
      char *user_agent_deprecated;
  #endif
      char *content_type;
      /* Set if the server correctly handles Connection: close and will close
       * the connection after feeding us the content. */
      int willclose;
      int seekable;           /**< Control seekability, 0 = disable, 1 = enable, -1 = probe. */
      int chunked_post;
      /* A flag which indicates if the end of chunked encoding has been sent. */
      int end_chunked_post;
      /* A flag which indicates we have finished to read POST reply. */
      int end_header;
      /* A flag which indicates if we use persistent connections. */
      int multiple_requests;
      uint8_t *post_data;
      int post_datalen;
      int is_akamai;
      int is_mediagateway;
      char *cookies;          ///< holds newline (\n) delimited Set-Cookie header field values (without the "Set-Cookie: " field name)
      /* A dictionary containing cookies keyed by cookie name */
      AVDictionary *cookie_dict;
      int icy;
      /* how much data was read since the last ICY metadata packet */
      uint64_t icy_data_read;
      /* after how many bytes of read data a new metadata packet will be found */
      uint64_t icy_metaint;
      char *icy_metadata_headers;
      char *icy_metadata_packet;
      AVDictionary *metadata;
  #if CONFIG_ZLIB
      int compressed;
      z_stream inflate_stream;
      uint8_t *inflate_buffer;
  #endif /* CONFIG_ZLIB */
      AVDictionary *chained_options;
      int send_expect_100;
      char *method;
      int reconnect;
      int reconnect_at_eof;
      int reconnect_streamed;
      int reconnect_delay;
      int reconnect_delay_max;
      int listen;
      char *resource;
      int reply_code;
      int is_multi_client;
      HandshakeState handshake_step;
      int is_connected_server;
  } HTTPContext;
  
  #define OFFSET(x) offsetof(HTTPContext, x)
  #define D AV_OPT_FLAG_DECODING_PARAM
  #define E AV_OPT_FLAG_ENCODING_PARAM
  #define DEFAULT_USER_AGENT "Lavf/" AV_STRINGIFY(LIBAVFORMAT_VERSION)
  
  static const AVOption options[] = {
      { "seekable", "control seekability of connection", OFFSET(seekable), AV_OPT_TYPE_BOOL, { .i64 = -1 }, -1, 1, D },
      { "chunked_post", "use chunked transfer-encoding for posts", OFFSET(chunked_post), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, E },
      { "http_proxy", "set HTTP proxy to tunnel through", OFFSET(http_proxy), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
      { "headers", "set custom HTTP headers, can override built in default headers", OFFSET(headers), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
      { "content_type", "set a specific content type for the POST messages", OFFSET(content_type), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
      { "user_agent", "override User-Agent header", OFFSET(user_agent), AV_OPT_TYPE_STRING, { .str = DEFAULT_USER_AGENT }, 0, 0, D },
  #if FF_API_HTTP_USER_AGENT
      { "user-agent", "override User-Agent header", OFFSET(user_agent_deprecated), AV_OPT_TYPE_STRING, { .str = DEFAULT_USER_AGENT }, 0, 0, D },
  #endif
      { "multiple_requests", "use persistent connections", OFFSET(multiple_requests), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D | E },
      { "post_data", "set custom HTTP post data", OFFSET(post_data), AV_OPT_TYPE_BINARY, .flags = D | E },
      { "mime_type", "export the MIME type", OFFSET(mime_type), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, AV_OPT_FLAG_EXPORT | AV_OPT_FLAG_READONLY },
      { "cookies", "set cookies to be sent in applicable future requests, use newline delimited Set-Cookie HTTP field value syntax", OFFSET(cookies), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D },
      { "icy", "request ICY metadata", OFFSET(icy), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, D },
      { "icy_metadata_headers", "return ICY metadata headers", OFFSET(icy_metadata_headers), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, AV_OPT_FLAG_EXPORT },
      { "icy_metadata_packet", "return current ICY metadata packet", OFFSET(icy_metadata_packet), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, AV_OPT_FLAG_EXPORT },
      { "metadata", "metadata read from the bitstream", OFFSET(metadata), AV_OPT_TYPE_DICT, {0}, 0, 0, AV_OPT_FLAG_EXPORT },
      { "auth_type", "HTTP authentication type", OFFSET(auth_state.auth_type), AV_OPT_TYPE_INT, { .i64 = HTTP_AUTH_NONE }, HTTP_AUTH_NONE, HTTP_AUTH_BASIC, D | E, "auth_type"},
      { "none", "No auth method set, autodetect", 0, AV_OPT_TYPE_CONST, { .i64 = HTTP_AUTH_NONE }, 0, 0, D | E, "auth_type"},
      { "basic", "HTTP basic authentication", 0, AV_OPT_TYPE_CONST, { .i64 = HTTP_AUTH_BASIC }, 0, 0, D | E, "auth_type"},
      { "send_expect_100", "Force sending an Expect: 100-continue header for POST", OFFSET(send_expect_100), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, E },
      { "location", "The actual location of the data received", OFFSET(location), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
      { "offset", "initial byte offset", OFFSET(off), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, D },
      { "end_offset", "try to limit the request to bytes preceding this offset", OFFSET(end_off), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT64_MAX, D },
      { "method", "Override the HTTP method or set the expected HTTP method from a client", OFFSET(method), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, D | E },
      { "reconnect", "auto reconnect after disconnect before EOF", OFFSET(reconnect), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
      { "reconnect_at_eof", "auto reconnect at EOF", OFFSET(reconnect_at_eof), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
      { "reconnect_streamed", "auto reconnect streamed / non seekable streams", OFFSET(reconnect_streamed), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, D },
      { "reconnect_delay_max", "max reconnect delay in seconds after which to give up", OFFSET(reconnect_delay_max), AV_OPT_TYPE_INT, { .i64 = 120 }, 0, UINT_MAX/1000/1000, D },
      { "listen", "listen on HTTP", OFFSET(listen), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 2, D | E },
      { "resource", "The resource requested by a client", OFFSET(resource), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, E },
      { "reply_code", "The http status code to return to a client", OFFSET(reply_code), AV_OPT_TYPE_INT, { .i64 = 200}, INT_MIN, 599, E},
      { NULL }
  };
  
  static int http_connect(URLContext *h, const char *path, const char *local_path,
                          const char *hoststr, const char *auth,
                          const char *proxyauth, int *new_location);
  static int http_read_header(URLContext *h, int *new_location);
  
  void ff_http_init_auth_state(URLContext *dest, const URLContext *src)
  {
      memcpy(&((HTTPContext *)dest->priv_data)->auth_state,
             &((HTTPContext *)src->priv_data)->auth_state,
             sizeof(HTTPAuthState));
      memcpy(&((HTTPContext *)dest->priv_data)->proxy_auth_state,
             &((HTTPContext *)src->priv_data)->proxy_auth_state,
             sizeof(HTTPAuthState));
  }
  
  static int http_open_cnx_internal(URLContext *h, AVDictionary **options)
  {
      const char *path, *proxy_path, *lower_proto = "tcp", *local_path;
      char hostname[1024], hoststr[1024], proto[10];
      char auth[1024], proxyauth[1024] = "";
      char path1[MAX_URL_SIZE];
      char buf[1024], urlbuf[MAX_URL_SIZE];
      int port, use_proxy, err, location_changed = 0;
      HTTPContext *s = h->priv_data;
  
      av_url_split(proto, sizeof(proto), auth, sizeof(auth),
                   hostname, sizeof(hostname), &port,
                   path1, sizeof(path1), s->location);
      ff_url_join(hoststr, sizeof(hoststr), NULL, NULL, hostname, port, NULL);
  
      proxy_path = s->http_proxy ? s->http_proxy : getenv("http_proxy");
      use_proxy  = !ff_http_match_no_proxy(getenv("no_proxy"), hostname) &&
                   proxy_path && av_strstart(proxy_path, "http://", NULL);
  
      if (!strcmp(proto, "https")) {
          lower_proto = "tls";
          use_proxy   = 0;
          if (port < 0)
              port = 443;
      }
      if (port < 0)
          port = 80;
  
      if (path1[0] == '\0')
          path = "/";
      else
          path = path1;
      local_path = path;
      if (use_proxy) {
          /* Reassemble the request URL without auth string - we don't
           * want to leak the auth to the proxy. */
          ff_url_join(urlbuf, sizeof(urlbuf), proto, NULL, hostname, port, "%s",
                      path1);
          path = urlbuf;
          av_url_split(NULL, 0, proxyauth, sizeof(proxyauth),
                       hostname, sizeof(hostname), &port, NULL, 0, proxy_path);
      }
  
      ff_url_join(buf, sizeof(buf), lower_proto, NULL, hostname, port, NULL);
  
      if (!s->hd) {
          err = ffurl_open_whitelist(&s->hd, buf, AVIO_FLAG_READ_WRITE,
                                     &h->interrupt_callback, options,
                                     h->protocol_whitelist, h->protocol_blacklist, h);
          if (err < 0)
              return err;
      }
  
      err = http_connect(h, path, local_path, hoststr,
                         auth, proxyauth, &location_changed);
      if (err < 0)
          return err;
  
      return location_changed;
  }
  
  /* return non zero if error */
  static int http_open_cnx(URLContext *h, AVDictionary **options)
  {
      HTTPAuthType cur_auth_type, cur_proxy_auth_type;
      HTTPContext *s = h->priv_data;
      int location_changed, attempts = 0, redirects = 0;
  redo:
      av_dict_copy(options, s->chained_options, 0);
  
      cur_auth_type       = s->auth_state.auth_type;
      cur_proxy_auth_type = s->auth_state.auth_type;
  
      location_changed = http_open_cnx_internal(h, options);
      if (location_changed < 0)
          goto fail;
  
      attempts++;
      if (s->http_code == 401) {
          if ((cur_auth_type == HTTP_AUTH_NONE || s->auth_state.stale) &&
              s->auth_state.auth_type != HTTP_AUTH_NONE && attempts < 4) {
              ffurl_closep(&s->hd);
              goto redo;
          } else
              goto fail;
      }
      if (s->http_code == 407) {
          if ((cur_proxy_auth_type == HTTP_AUTH_NONE || s->proxy_auth_state.stale) &&
              s->proxy_auth_state.auth_type != HTTP_AUTH_NONE && attempts < 4) {
              ffurl_closep(&s->hd);
              goto redo;
          } else
              goto fail;
      }
      if ((s->http_code == 301 || s->http_code == 302 ||
           s->http_code == 303 || s->http_code == 307) &&
          location_changed == 1) {
          /* url moved, get next */
          ffurl_closep(&s->hd);
          if (redirects++ >= MAX_REDIRECTS)
              return AVERROR(EIO);
          /* Restart the authentication process with the new target, which
           * might use a different auth mechanism. */
          memset(&s->auth_state, 0, sizeof(s->auth_state));
          attempts         = 0;
          location_changed = 0;
          goto redo;
      }
      return 0;
  
  fail:
      if (s->hd)
          ffurl_closep(&s->hd);
      if (location_changed < 0)
          return location_changed;
      return ff_http_averror(s->http_code, AVERROR(EIO));
  }
  
  int ff_http_do_new_request(URLContext *h, const char *uri)
  {
      HTTPContext *s = h->priv_data;
      AVDictionary *options = NULL;
      int ret;
  
      s->off           = 0;
      s->icy_data_read = 0;
      av_free(s->location);
      s->location = av_strdup(uri);
      if (!s->location)
          return AVERROR(ENOMEM);
  
      ret = http_open_cnx(h, &options);
      av_dict_free(&options);
      return ret;
  }
  
  int ff_http_averror(int status_code, int default_averror)
  {
      switch (status_code) {
          case 400: return AVERROR_HTTP_BAD_REQUEST;
          case 401: return AVERROR_HTTP_UNAUTHORIZED;
          case 403: return AVERROR_HTTP_FORBIDDEN;
          case 404: return AVERROR_HTTP_NOT_FOUND;
          default: break;
      }
      if (status_code >= 400 && status_code <= 499)
          return AVERROR_HTTP_OTHER_4XX;
      else if (status_code >= 500)
          return AVERROR_HTTP_SERVER_ERROR;
      else
          return default_averror;
  }
  
  static int http_write_reply(URLContext* h, int status_code)
  {
      int ret, body = 0, reply_code, message_len;
      const char *reply_text, *content_type;
      HTTPContext *s = h->priv_data;
      char message[BUFFER_SIZE];
      content_type = "text/plain";
  
      if (status_code < 0)
          body = 1;
      switch (status_code) {
      case AVERROR_HTTP_BAD_REQUEST:
      case 400:
          reply_code = 400;
          reply_text = "Bad Request";
          break;
      case AVERROR_HTTP_FORBIDDEN:
      case 403:
          reply_code = 403;
          reply_text = "Forbidden";
          break;
      case AVERROR_HTTP_NOT_FOUND:
      case 404:
          reply_code = 404;
          reply_text = "Not Found";
          break;
      case 200:
          reply_code = 200;
          reply_text = "OK";
          content_type = s->content_type ? s->content_type : "application/octet-stream";
          break;
      case AVERROR_HTTP_SERVER_ERROR:
      case 500:
          reply_code = 500;
          reply_text = "Internal server error";
          break;
      default:
          return AVERROR(EINVAL);
      }
      if (body) {
          s->chunked_post = 0;
          message_len = snprintf(message, sizeof(message),
                   "HTTP/1.1 %03d %s\r\n"
                   "Content-Type: %s\r\n"
                   "Content-Length: %"SIZE_SPECIFIER"\r\n"
                   "%s"
                   "\r\n"
                   "%03d %s\r\n",
                   reply_code,
                   reply_text,
                   content_type,
                   strlen(reply_text) + 6, // 3 digit status code + space + \r\n
                   s->headers ? s->headers : "",
                   reply_code,
                   reply_text);
      } else {
          s->chunked_post = 1;
          message_len = snprintf(message, sizeof(message),
                   "HTTP/1.1 %03d %s\r\n"
                   "Content-Type: %s\r\n"
                   "Transfer-Encoding: chunked\r\n"
                   "%s"
                   "\r\n",
                   reply_code,
                   reply_text,
                   content_type,
                   s->headers ? s->headers : "");
      }
      av_log(h, AV_LOG_TRACE, "HTTP reply header: \n%s----\n", message);
      if ((ret = ffurl_write(s->hd, message, message_len)) < 0)
          return ret;
      return 0;
  }
  
  static void handle_http_errors(URLContext *h, int error)
  {
      av_assert0(error < 0);
      http_write_reply(h, error);
  }
  
  static int http_handshake(URLContext *c)
  {
      int ret, err, new_location;
      HTTPContext *ch = c->priv_data;
      URLContext *cl = ch->hd;
      switch (ch->handshake_step) {
      case LOWER_PROTO:
          av_log(c, AV_LOG_TRACE, "Lower protocol\n");
          if ((ret = ffurl_handshake(cl)) > 0)
              return 2 + ret;
          if (ret < 0)
              return ret;
          ch->handshake_step = READ_HEADERS;
          ch->is_connected_server = 1;
          return 2;
      case READ_HEADERS:
          av_log(c, AV_LOG_TRACE, "Read headers\n");
          if ((err = http_read_header(c, &new_location)) < 0) {
              handle_http_errors(c, err);
              return err;
          }
          ch->handshake_step = WRITE_REPLY_HEADERS;
          return 1;
      case WRITE_REPLY_HEADERS:
          av_log(c, AV_LOG_TRACE, "Reply code: %d\n", ch->reply_code);
          if ((err = http_write_reply(c, ch->reply_code)) < 0)
              return err;
          ch->handshake_step = FINISH;
          return 1;
      case FINISH:
          return 0;
      }
      // this should never be reached.
      return AVERROR(EINVAL);
  }
  
  static int http_listen(URLContext *h, const char *uri, int flags,
                         AVDictionary **options) {
      HTTPContext *s = h->priv_data;
      int ret;
      char hostname[1024], proto[10];
      char lower_url[100];
      const char *lower_proto = "tcp";
      int port;
      av_url_split(proto, sizeof(proto), NULL, 0, hostname, sizeof(hostname), &port,
                   NULL, 0, uri);
      if (!strcmp(proto, "https"))
          lower_proto = "tls";
      ff_url_join(lower_url, sizeof(lower_url), lower_proto, NULL, hostname, port,
                  NULL);
      if ((ret = av_dict_set_int(options, "listen", s->listen, 0)) < 0)
          goto fail;
      if ((ret = ffurl_open_whitelist(&s->hd, lower_url, AVIO_FLAG_READ_WRITE,
                                      &h->interrupt_callback, options,
                                      h->protocol_whitelist, h->protocol_blacklist, h
                                     )) < 0)
          goto fail;
      s->handshake_step = LOWER_PROTO;
      if (s->listen == HTTP_SINGLE) { /* single client */
          s->reply_code = 200;
          while ((ret = http_handshake(h)) > 0);
      }
  fail:
      av_dict_free(&s->chained_options);
      return ret;
  }
  
  static int http_open(URLContext *h, const char *uri, int flags,
                       AVDictionary **options)
  {
      HTTPContext *s = h->priv_data;
      int ret;
  
      if( s->seekable == 1 )
          h->is_streamed = 0;
      else
          h->is_streamed = 1;
  
      s->filesize = UINT64_MAX;
      s->location = av_strdup(uri);
      if (!s->location)
          return AVERROR(ENOMEM);
      if (options)
          av_dict_copy(&s->chained_options, *options, 0);
  
      if (s->headers) {
          int len = strlen(s->headers);
          if (len < 2 || strcmp("\r\n", s->headers + len - 2)) {
              av_log(h, AV_LOG_WARNING,
                     "No trailing CRLF found in HTTP header.\n");
              ret = av_reallocp(&s->headers, len + 3);
              if (ret < 0)
                  return ret;
              s->headers[len]     = '\r';
              s->headers[len + 1] = '\n';
              s->headers[len + 2] = '\0';
          }
      }
  
      if (s->listen) {
          return http_listen(h, uri, flags, options);
      }
      ret = http_open_cnx(h, options);
      if (ret < 0)
          av_dict_free(&s->chained_options);
      return ret;
  }
  
  static int http_accept(URLContext *s, URLContext **c)
  {
      int ret;
      HTTPContext *sc = s->priv_data;
      HTTPContext *cc;
      URLContext *sl = sc->hd;
      URLContext *cl = NULL;
  
      av_assert0(sc->listen);
      if ((ret = ffurl_alloc(c, s->filename, s->flags, &sl->interrupt_callback)) < 0)
          goto fail;
      cc = (*c)->priv_data;
      if ((ret = ffurl_accept(sl, &cl)) < 0)
          goto fail;
      cc->hd = cl;
      cc->is_multi_client = 1;
  fail:
      return ret;
  }
  
  static int http_getc(HTTPContext *s)
  {
      int len;
      if (s->buf_ptr >= s->buf_end) {
          len = ffurl_read(s->hd, s->buffer, BUFFER_SIZE);
          if (len < 0) {
              return len;
          } else if (len == 0) {
              return AVERROR_EOF;
          } else {
              s->buf_ptr = s->buffer;
              s->buf_end = s->buffer + len;
          }
      }
      return *s->buf_ptr++;
  }
  
  static int http_get_line(HTTPContext *s, char *line, int line_size)
  {
      int ch;
      char *q;
  
      q = line;
      for (;;) {
          ch = http_getc(s);
          if (ch < 0)
              return ch;
          if (ch == '\n') {
              /* process line */
              if (q > line && q[-1] == '\r')
                  q--;
              *q = '\0';
  
              return 0;
          } else {
              if ((q - line) < line_size - 1)
                  *q++ = ch;
          }
      }
  }
  
  static int check_http_code(URLContext *h, int http_code, const char *end)
  {
      HTTPContext *s = h->priv_data;
      /* error codes are 4xx and 5xx, but regard 401 as a success, so we
       * don't abort until all headers have been parsed. */
      if (http_code >= 400 && http_code < 600 &&
          (http_code != 401 || s->auth_state.auth_type != HTTP_AUTH_NONE) &&
          (http_code != 407 || s->proxy_auth_state.auth_type != HTTP_AUTH_NONE)) {
          end += strspn(end, SPACE_CHARS);
          av_log(h, AV_LOG_WARNING, "HTTP error %d %s\n", http_code, end);
          return ff_http_averror(http_code, AVERROR(EIO));
      }
      return 0;
  }
  
  static int parse_location(HTTPContext *s, const char *p)
  {
      char redirected_location[MAX_URL_SIZE], *new_loc;
      ff_make_absolute_url(redirected_location, sizeof(redirected_location),
                           s->location, p);
      new_loc = av_strdup(redirected_location);
      if (!new_loc)
          return AVERROR(ENOMEM);
      av_free(s->location);
      s->location = new_loc;
      return 0;
  }
  
  /* "bytes $from-$to/$document_size" */
  static void parse_content_range(URLContext *h, const char *p)
  {
      HTTPContext *s = h->priv_data;
      const char *slash;
  
      if (!strncmp(p, "bytes ", 6)) {
          p     += 6;
          s->off = strtoull(p, NULL, 10);
          if ((slash = strchr(p, '/')) && strlen(slash) > 0)
              s->filesize = strtoull(slash + 1, NULL, 10);
      }
      if (s->seekable == -1 && (!s->is_akamai || s->filesize != 2147483647))
          h->is_streamed = 0; /* we _can_ in fact seek */
  }
  
  static int parse_content_encoding(URLContext *h, const char *p)
  {
      if (!av_strncasecmp(p, "gzip", 4) ||
          !av_strncasecmp(p, "deflate", 7)) {
  #if CONFIG_ZLIB
          HTTPContext *s = h->priv_data;
  
          s->compressed = 1;
          inflateEnd(&s->inflate_stream);
          if (inflateInit2(&s->inflate_stream, 32 + 15) != Z_OK) {
              av_log(h, AV_LOG_WARNING, "Error during zlib initialisation: %s\n",
                     s->inflate_stream.msg);
              return AVERROR(ENOSYS);
          }
          if (zlibCompileFlags() & (1 << 17)) {
              av_log(h, AV_LOG_WARNING,
                     "Your zlib was compiled without gzip support.\n");
              return AVERROR(ENOSYS);
          }
  #else
          av_log(h, AV_LOG_WARNING,
                 "Compressed (%s) content, need zlib with gzip support\n", p);
          return AVERROR(ENOSYS);
  #endif /* CONFIG_ZLIB */
      } else if (!av_strncasecmp(p, "identity", 8)) {
          // The normal, no-encoding case (although servers shouldn't include
          // the header at all if this is the case).
      } else {
          av_log(h, AV_LOG_WARNING, "Unknown content coding: %s\n", p);
      }
      return 0;
  }
  
  // Concat all Icy- header lines
  static int parse_icy(HTTPContext *s, const char *tag, const char *p)
  {
      int len = 4 + strlen(p) + strlen(tag);
      int is_first = !s->icy_metadata_headers;
      int ret;
  
      av_dict_set(&s->metadata, tag, p, 0);
  
      if (s->icy_metadata_headers)
          len += strlen(s->icy_metadata_headers);
  
      if ((ret = av_reallocp(&s->icy_metadata_headers, len)) < 0)
          return ret;
  
      if (is_first)
          *s->icy_metadata_headers = '\0';
  
      av_strlcatf(s->icy_metadata_headers, len, "%s: %s\n", tag, p);
  
      return 0;
  }
  
  static int parse_set_cookie_expiry_time(const char *exp_str, struct tm *buf)
  {
      char exp_buf[MAX_EXPIRY];
      int i, j, exp_buf_len = MAX_EXPIRY-1;
      char *expiry;
  
      // strip off any punctuation or whitespace
      for (i = 0, j = 0; exp_str[i] != '\0' && j < exp_buf_len; i++) {
          if ((exp_str[i] >= '0' && exp_str[i] <= '9') ||
              (exp_str[i] >= 'A' && exp_str[i] <= 'Z') ||
              (exp_str[i] >= 'a' && exp_str[i] <= 'z')) {
              exp_buf[j] = exp_str[i];
              j++;
          }
      }
      exp_buf[j] = '\0';
      expiry = exp_buf;
  
      // move the string beyond the day of week
      while ((*expiry < '0' || *expiry > '9') && *expiry != '\0')
          expiry++;
  
      return av_small_strptime(expiry, "%d%b%Y%H%M%S", buf) ? 0 : AVERROR(EINVAL);
  }
  
  static int parse_set_cookie(const char *set_cookie, AVDictionary **dict)
  {
      char *param, *next_param, *cstr, *back;
  
      if (!(cstr = av_strdup(set_cookie)))
          return AVERROR(EINVAL);
  
      // strip any trailing whitespace
      back = &cstr[strlen(cstr)-1];
      while (strchr(WHITESPACES, *back)) {
          *back='\0';
          back--;
      }
  
      next_param = cstr;
      while ((param = av_strtok(next_param, ";", &next_param))) {
          char *name, *value;
          param += strspn(param, WHITESPACES);
          if ((name = av_strtok(param, "=", &value))) {
              if (av_dict_set(dict, name, value, 0) < 0) {
                  av_free(cstr);
                  return -1;
              }
          }
      }
  
      av_free(cstr);
      return 0;
  }
  
  static int parse_cookie(HTTPContext *s, const char *p, AVDictionary **cookies)
  {
      AVDictionary *new_params = NULL;
      AVDictionaryEntry *e, *cookie_entry;
      char *eql, *name;
  
      // ensure the cookie is parsable
      if (parse_set_cookie(p, &new_params))
          return -1;
  
      // if there is no cookie value there is nothing to parse
      cookie_entry = av_dict_get(new_params, "", NULL, AV_DICT_IGNORE_SUFFIX);
      if (!cookie_entry || !cookie_entry->value) {
          av_dict_free(&new_params);
          return -1;
      }
  
      // ensure the cookie is not expired or older than an existing value
      if ((e = av_dict_get(new_params, "expires", NULL, 0)) && e->value) {
          struct tm new_tm = {0};
          if (!parse_set_cookie_expiry_time(e->value, &new_tm)) {
              AVDictionaryEntry *e2;
  
              // if the cookie has already expired ignore it
              if (av_timegm(&new_tm) < av_gettime() / 1000000) {
                  av_dict_free(&new_params);
                  return -1;
              }
  
              // only replace an older cookie with the same name
              e2 = av_dict_get(*cookies, cookie_entry->key, NULL, 0);
              if (e2 && e2->value) {
                  AVDictionary *old_params = NULL;
                  if (!parse_set_cookie(p, &old_params)) {
                      e2 = av_dict_get(old_params, "expires", NULL, 0);
                      if (e2 && e2->value) {
                          struct tm old_tm = {0};
                          if (!parse_set_cookie_expiry_time(e->value, &old_tm)) {
                              if (av_timegm(&new_tm) < av_timegm(&old_tm)) {
                                  av_dict_free(&new_params);
                                  av_dict_free(&old_params);
                                  return -1;
                              }
                          }
                      }
                  }
                  av_dict_free(&old_params);
              }
          }
      }
  
      // duplicate the cookie name (dict will dupe the value)
      if (!(eql = strchr(p, '='))) return AVERROR(EINVAL);
      if (!(name = av_strndup(p, eql - p))) return AVERROR(ENOMEM);
  
      // add the cookie to the dictionary
      av_dict_set(cookies, name, eql, AV_DICT_DONT_STRDUP_KEY);
  
      return 0;
  }
  
  static int cookie_string(AVDictionary *dict, char **cookies)
  {
      AVDictionaryEntry *e = NULL;
      int len = 1;
  
      // determine how much memory is needed for the cookies string
      while (e = av_dict_get(dict, "", e, AV_DICT_IGNORE_SUFFIX))
          len += strlen(e->key) + strlen(e->value) + 1;
  
      // reallocate the cookies
      e = NULL;
      if (*cookies) av_free(*cookies);
      *cookies = av_malloc(len);
      if (!*cookies) return AVERROR(ENOMEM);
      *cookies[0] = '\0';
  
      // write out the cookies
      while (e = av_dict_get(dict, "", e, AV_DICT_IGNORE_SUFFIX))
          av_strlcatf(*cookies, len, "%s%s\n", e->key, e->value);
  
      return 0;
  }
  
  static int process_line(URLContext *h, char *line, int line_count,
                          int *new_location)
  {
      HTTPContext *s = h->priv_data;
      const char *auto_method =  h->flags & AVIO_FLAG_READ ? "POST" : "GET";
      char *tag, *p, *end, *method, *resource, *version;
      int ret;
  
      /* end of header */
      if (line[0] == '\0') {
          s->end_header = 1;
          return 0;
      }
  
      p = line;
      if (line_count == 0) {
          if (s->is_connected_server) {
              // HTTP method
              method = p;
              while (*p && !av_isspace(*p))
                  p++;
              *(p++) = '\0';
              av_log(h, AV_LOG_TRACE, "Received method: %s\n", method);
              if (s->method) {
                  if (av_strcasecmp(s->method, method)) {
                      av_log(h, AV_LOG_ERROR, "Received and expected HTTP method do not match. (%s expected, %s received)\n",
                             s->method, method);
                      return ff_http_averror(400, AVERROR(EIO));
                  }
              } else {
                  // use autodetected HTTP method to expect
                  av_log(h, AV_LOG_TRACE, "Autodetected %s HTTP method\n", auto_method);
                  if (av_strcasecmp(auto_method, method)) {
                      av_log(h, AV_LOG_ERROR, "Received and autodetected HTTP method did not match "
                             "(%s autodetected %s received)\n", auto_method, method);
                      return ff_http_averror(400, AVERROR(EIO));
                  }
                  if (!(s->method = av_strdup(method)))
                      return AVERROR(ENOMEM);
              }
  
              // HTTP resource
              while (av_isspace(*p))
                  p++;
              resource = p;
              while (!av_isspace(*p))
                  p++;
              *(p++) = '\0';
              av_log(h, AV_LOG_TRACE, "Requested resource: %s\n", resource);
              if (!(s->resource = av_strdup(resource)))
                  return AVERROR(ENOMEM);
  
              // HTTP version
              while (av_isspace(*p))
                  p++;
              version = p;
              while (*p && !av_isspace(*p))
                  p++;
              *p = '\0';
              if (av_strncasecmp(version, "HTTP/", 5)) {
                  av_log(h, AV_LOG_ERROR, "Malformed HTTP version string.\n");
                  return ff_http_averror(400, AVERROR(EIO));
              }
              av_log(h, AV_LOG_TRACE, "HTTP version string: %s\n", version);
          } else {
              while (!av_isspace(*p) && *p != '\0')
                  p++;
              while (av_isspace(*p))
                  p++;
              s->http_code = strtol(p, &end, 10);
  
              av_log(h, AV_LOG_TRACE, "http_code=%d\n", s->http_code);
  
              if ((ret = check_http_code(h, s->http_code, end)) < 0)
                  return ret;
          }
      } else {
          while (*p != '\0' && *p != ':')
              p++;
          if (*p != ':')
              return 1;
  
          *p  = '\0';
          tag = line;
          p++;
          while (av_isspace(*p))
              p++;
          if (!av_strcasecmp(tag, "Location")) {
              if ((ret = parse_location(s, p)) < 0)
                  return ret;
              *new_location = 1;
          } else if (!av_strcasecmp(tag, "Content-Length") &&
                     s->filesize == UINT64_MAX) {
              s->filesize = strtoull(p, NULL, 10);
          } else if (!av_strcasecmp(tag, "Content-Range")) {
              parse_content_range(h, p);
          } else if (!av_strcasecmp(tag, "Accept-Ranges") &&
                     !strncmp(p, "bytes", 5) &&
                     s->seekable == -1) {
              h->is_streamed = 0;
          } else if (!av_strcasecmp(tag, "Transfer-Encoding") &&
                     !av_strncasecmp(p, "chunked", 7)) {
              s->filesize  = UINT64_MAX;
              s->chunksize = 0;
          } else if (!av_strcasecmp(tag, "WWW-Authenticate")) {
              ff_http_auth_handle_header(&s->auth_state, tag, p);
          } else if (!av_strcasecmp(tag, "Authentication-Info")) {
              ff_http_auth_handle_header(&s->auth_state, tag, p);
          } else if (!av_strcasecmp(tag, "Proxy-Authenticate")) {
              ff_http_auth_handle_header(&s->proxy_auth_state, tag, p);
          } else if (!av_strcasecmp(tag, "Connection")) {
              if (!strcmp(p, "close"))
                  s->willclose = 1;
          } else if (!av_strcasecmp(tag, "Server")) {
              if (!av_strcasecmp(p, "AkamaiGHost")) {
                  s->is_akamai = 1;
              } else if (!av_strncasecmp(p, "MediaGateway", 12)) {
                  s->is_mediagateway = 1;
              }
          } else if (!av_strcasecmp(tag, "Content-Type")) {
              av_free(s->mime_type);
              s->mime_type = av_strdup(p);
          } else if (!av_strcasecmp(tag, "Set-Cookie")) {
              if (parse_cookie(s, p, &s->cookie_dict))
                  av_log(h, AV_LOG_WARNING, "Unable to parse '%s'\n", p);
          } else if (!av_strcasecmp(tag, "Icy-MetaInt")) {
              s->icy_metaint = strtoull(p, NULL, 10);
          } else if (!av_strncasecmp(tag, "Icy-", 4)) {
              if ((ret = parse_icy(s, tag, p)) < 0)
                  return ret;
          } else if (!av_strcasecmp(tag, "Content-Encoding")) {
              if ((ret = parse_content_encoding(h, p)) < 0)
                  return ret;
          }
      }
      return 1;
  }
  
  /**
   * Create a string containing cookie values for use as a HTTP cookie header
   * field value for a particular path and domain from the cookie values stored in
   * the HTTP protocol context. The cookie string is stored in *cookies.
   *
   * @return a negative value if an error condition occurred, 0 otherwise
   */
  static int get_cookies(HTTPContext *s, char **cookies, const char *path,
                         const char *domain)
  {
      // cookie strings will look like Set-Cookie header field values.  Multiple
      // Set-Cookie fields will result in multiple values delimited by a newline
      int ret = 0;
      char *cookie, *set_cookies = av_strdup(s->cookies), *next = set_cookies;
  
      if (!set_cookies) return AVERROR(EINVAL);
  
      // destroy any cookies in the dictionary.
      av_dict_free(&s->cookie_dict);
  
      *cookies = NULL;
      while ((cookie = av_strtok(next, "\n", &next))) {
          AVDictionary *cookie_params = NULL;
          AVDictionaryEntry *cookie_entry, *e;
  
          // store the cookie in a dict in case it is updated in the response
          if (parse_cookie(s, cookie, &s->cookie_dict))
              av_log(s, AV_LOG_WARNING, "Unable to parse '%s'\n", cookie);
  
          // continue on to the next cookie if this one cannot be parsed
          if (parse_set_cookie(cookie, &cookie_params))
              continue;
  
          // if the cookie has no value, skip it
          cookie_entry = av_dict_get(cookie_params, "", NULL, AV_DICT_IGNORE_SUFFIX);
          if (!cookie_entry || !cookie_entry->value) {
              av_dict_free(&cookie_params);
              continue;
          }
  
          // if the cookie has expired, don't add it
          if ((e = av_dict_get(cookie_params, "expires", NULL, 0)) && e->value) {
              struct tm tm_buf = {0};
              if (!parse_set_cookie_expiry_time(e->value, &tm_buf)) {
                  if (av_timegm(&tm_buf) < av_gettime() / 1000000) {
                      av_dict_free(&cookie_params);
                      continue;
                  }
              }
          }
  
          // if no domain in the cookie assume it appied to this request
          if ((e = av_dict_get(cookie_params, "domain", NULL, 0)) && e->value) {
              // find the offset comparison is on the min domain (b.com, not a.b.com)
              int domain_offset = strlen(domain) - strlen(e->value);
              if (domain_offset < 0) {
                  av_dict_free(&cookie_params);
                  continue;
              }
  
              // match the cookie domain
              if (av_strcasecmp(&domain[domain_offset], e->value)) {
                  av_dict_free(&cookie_params);
                  continue;
              }
          }
  
          // ensure this cookie matches the path
          e = av_dict_get(cookie_params, "path", NULL, 0);
          if (!e || av_strncasecmp(path, e->value, strlen(e->value))) {
              av_dict_free(&cookie_params);
              continue;
          }
  
          // cookie parameters match, so copy the value
          if (!*cookies) {
              if (!(*cookies = av_asprintf("%s=%s", cookie_entry->key, cookie_entry->value))) {
                  ret = AVERROR(ENOMEM);
                  break;
              }
          } else {
              char *tmp = *cookies;
              size_t str_size = strlen(cookie_entry->key) + strlen(cookie_entry->value) + strlen(*cookies) + 4;
              if (!(*cookies = av_malloc(str_size))) {
                  ret = AVERROR(ENOMEM);
                  av_free(tmp);
                  break;
              }
              snprintf(*cookies, str_size, "%s; %s=%s", tmp, cookie_entry->key, cookie_entry->value);
              av_free(tmp);
          }
      }
  
      av_free(set_cookies);
  
      return ret;
  }
  
  static inline int has_header(const char *str, const char *header)
  {
      /* header + 2 to skip over CRLF prefix. (make sure you have one!) */
      if (!str)
          return 0;
      return av_stristart(str, header + 2, NULL) || av_stristr(str, header);
  }
  
  static int http_read_header(URLContext *h, int *new_location)
  {
      HTTPContext *s = h->priv_data;
      char line[MAX_URL_SIZE];
      int err = 0;
  
      s->chunksize = UINT64_MAX;
  
      for (;;) {
          if ((err = http_get_line(s, line, sizeof(line))) < 0)
              return err;
  
          av_log(h, AV_LOG_TRACE, "header='%s'\n", line);
  
          err = process_line(h, line, s->line_count, new_location);
          if (err < 0)
              return err;
          if (err == 0)
              break;
          s->line_count++;
      }
  
      if (s->seekable == -1 && s->is_mediagateway && s->filesize == 2000000000)
          h->is_streamed = 1; /* we can in fact _not_ seek */
  
      // add any new cookies into the existing cookie string
      cookie_string(s->cookie_dict, &s->cookies);
      av_dict_free(&s->cookie_dict);
  
      return err;
  }
  
  static int http_connect(URLContext *h, const char *path, const char *local_path,
                          const char *hoststr, const char *auth,
                          const char *proxyauth, int *new_location)
  {
      HTTPContext *s = h->priv_data;
      int post, err;
      char headers[HTTP_HEADERS_SIZE] = "";
      char *authstr = NULL, *proxyauthstr = NULL;
      uint64_t off = s->off;
      int len = 0;
      const char *method;
      int send_expect_100 = 0;
      int ret;
  
      /* send http header */
      post = h->flags & AVIO_FLAG_WRITE;
  
      if (s->post_data) {
          /* force POST method and disable chunked encoding when
           * custom HTTP post data is set */
          post            = 1;
          s->chunked_post = 0;
      }
  
      if (s->method)
          method = s->method;
      else
          method = post ? "POST" : "GET";
  
      authstr      = ff_http_auth_create_response(&s->auth_state, auth,
                                                  local_path, method);
      proxyauthstr = ff_http_auth_create_response(&s->proxy_auth_state, proxyauth,
                                                  local_path, method);
      if (post && !s->post_data) {
          send_expect_100 = s->send_expect_100;
          /* The user has supplied authentication but we don't know the auth type,
           * send Expect: 100-continue to get the 401 response including the
           * WWW-Authenticate header, or an 100 continue if no auth actually
           * is needed. */
          if (auth && *auth &&
              s->auth_state.auth_type == HTTP_AUTH_NONE &&
              s->http_code != 401)
              send_expect_100 = 1;
      }
  
  #if FF_API_HTTP_USER_AGENT
      if (strcmp(s->user_agent_deprecated, DEFAULT_USER_AGENT)) {
          av_log(s, AV_LOG_WARNING, "the user-agent option is deprecated, please use user_agent option\n");
          s->user_agent = av_strdup(s->user_agent_deprecated);
      }
  #endif
      /* set default headers if needed */
      if (!has_header(s->headers, "\r\nUser-Agent: "))
          len += av_strlcatf(headers + len, sizeof(headers) - len,
                             "User-Agent: %s\r\n", s->user_agent);
      if (!has_header(s->headers, "\r\nAccept: "))
          len += av_strlcpy(headers + len, "Accept: */*\r\n",
                            sizeof(headers) - len);
      // Note: we send this on purpose even when s->off is 0 when we're probing,
      // since it allows us to detect more reliably if a (non-conforming)
      // server supports seeking by analysing the reply headers.
      if (!has_header(s->headers, "\r\nRange: ") && !post && (s->off > 0 || s->end_off || s->seekable == -1)) {
          len += av_strlcatf(headers + len, sizeof(headers) - len,
                             "Range: bytes=%"PRIu64"-", s->off);
          if (s->end_off)
              len += av_strlcatf(headers + len, sizeof(headers) - len,
                                 "%"PRId64, s->end_off - 1);
          len += av_strlcpy(headers + len, "\r\n",
                            sizeof(headers) - len);
      }
      if (send_expect_100 && !has_header(s->headers, "\r\nExpect: "))
          len += av_strlcatf(headers + len, sizeof(headers) - len,
                             "Expect: 100-continue\r\n");
  
      if (!has_header(s->headers, "\r\nConnection: ")) {
          if (s->multiple_requests)
              len += av_strlcpy(headers + len, "Connection: keep-alive\r\n",
                                sizeof(headers) - len);
          else
              len += av_strlcpy(headers + len, "Connection: close\r\n",
                                sizeof(headers) - len);
      }
  
      if (!has_header(s->headers, "\r\nHost: "))
          len += av_strlcatf(headers + len, sizeof(headers) - len,
                             "Host: %s\r\n", hoststr);
      if (!has_header(s->headers, "\r\nContent-Length: ") && s->post_data)
          len += av_strlcatf(headers + len, sizeof(headers) - len,
                             "Content-Length: %d\r\n", s->post_datalen);
  
      if (!has_header(s->headers, "\r\nContent-Type: ") && s->content_type)
          len += av_strlcatf(headers + len, sizeof(headers) - len,
                             "Content-Type: %s\r\n", s->content_type);
      if (!has_header(s->headers, "\r\nCookie: ") && s->cookies) {
          char *cookies = NULL;
          if (!get_cookies(s, &cookies, path, hoststr) && cookies) {
              len += av_strlcatf(headers + len, sizeof(headers) - len,
                                 "Cookie: %s\r\n", cookies);
              av_free(cookies);
          }
      }
      if (!has_header(s->headers, "\r\nIcy-MetaData: ") && s->icy)
          len += av_strlcatf(headers + len, sizeof(headers) - len,
                             "Icy-MetaData: %d\r\n", 1);
  
      /* now add in custom headers */
      if (s->headers)
          av_strlcpy(headers + len, s->headers, sizeof(headers) - len);
  
      ret = snprintf(s->buffer, sizeof(s->buffer),
               "%s %s HTTP/1.1\r\n"
               "%s"
               "%s"
               "%s"
               "%s%s"
               "\r\n",
               method,
               path,
               post && s->chunked_post ? "Transfer-Encoding: chunked\r\n" : "",
               headers,
               authstr ? authstr : "",
               proxyauthstr ? "Proxy-" : "", proxyauthstr ? proxyauthstr : "");
  
      av_log(h, AV_LOG_DEBUG, "request: %s\n", s->buffer);
  
      if (strlen(headers) + 1 == sizeof(headers) ||
          ret >= sizeof(s->buffer)) {
          av_log(h, AV_LOG_ERROR, "overlong headers\n");
          err = AVERROR(EINVAL);
          goto done;
      }
  
  
      if ((err = ffurl_write(s->hd, s->buffer, strlen(s->buffer))) < 0)
          goto done;
  
      if (s->post_data)
          if ((err = ffurl_write(s->hd, s->post_data, s->post_datalen)) < 0)
              goto done;
  
      /* init input buffer */
      s->buf_ptr          = s->buffer;
      s->buf_end          = s->buffer;
      s->line_count       = 0;
      s->off              = 0;
      s->icy_data_read    = 0;
      s->filesize         = UINT64_MAX;
      s->willclose        = 0;
      s->end_chunked_post = 0;
      s->end_header       = 0;
  #if CONFIG_ZLIB
      s->compressed       = 0;
  #endif
      if (post && !s->post_data && !send_expect_100) {
          /* Pretend that it did work. We didn't read any header yet, since
           * we've still to send the POST data, but the code calling this
           * function will check http_code after we return. */
          s->http_code = 200;
          err = 0;
          goto done;
      }
  
      /* wait for header */
      err = http_read_header(h, new_location);
      if (err < 0)
          goto done;
  
      if (*new_location)
          s->off = off;
  
      err = (off == s->off) ? 0 : -1;
  done:
      av_freep(&authstr);
      av_freep(&proxyauthstr);
      return err;
  }
  
  static int http_buf_read(URLContext *h, uint8_t *buf, int size)
  {
      HTTPContext *s = h->priv_data;
      int len;
  
      if (s->chunksize != UINT64_MAX) {
          if (!s->chunksize) {
              char line[32];
              int err;
  
              do {
                  if ((err = http_get_line(s, line, sizeof(line))) < 0)
                      return err;
              } while (!*line);    /* skip CR LF from last chunk */
  
              s->chunksize = strtoull(line, NULL, 16);
  
              av_log(h, AV_LOG_TRACE,
                     "Chunked encoding data size: %"PRIu64"'\n",
                      s->chunksize);
  
              if (!s->chunksize)
                  return 0;
              else if (s->chunksize == UINT64_MAX) {
                  av_log(h, AV_LOG_ERROR, "Invalid chunk size %"PRIu64"\n",
                         s->chunksize);
                  return AVERROR(EINVAL);
              }
          }
          size = FFMIN(size, s->chunksize);
      }
  
      /* read bytes from input buffer first */
      len = s->buf_end - s->buf_ptr;
      if (len > 0) {
          if (len > size)
              len = size;
          memcpy(buf, s->buf_ptr, len);
          s->buf_ptr += len;
      } else {
          uint64_t target_end = s->end_off ? s->end_off : s->filesize;
          if ((!s->willclose || s->chunksize == UINT64_MAX) && s->off >= target_end)
              return AVERROR_EOF;
          len = ffurl_read(s->hd, buf, size);
          if (!len && (!s->willclose || s->chunksize == UINT64_MAX) && s->off < target_end) {
              av_log(h, AV_LOG_ERROR,
                     "Stream ends prematurely at %"PRIu64", should be %"PRIu64"\n",
                     s->off, target_end
                    );
              return AVERROR(EIO);
          }
      }
      if (len > 0) {
          s->off += len;
          if (s->chunksize > 0 && s->chunksize != UINT64_MAX) {
              av_assert0(s->chunksize >= len);
              s->chunksize -= len;
          }
      }
      return len;
  }
  
  #if CONFIG_ZLIB
  #define DECOMPRESS_BUF_SIZE (256 * 1024)
  static int http_buf_read_compressed(URLContext *h, uint8_t *buf, int size)
  {
      HTTPContext *s = h->priv_data;
      int ret;
  
      if (!s->inflate_buffer) {
          s->inflate_buffer = av_malloc(DECOMPRESS_BUF_SIZE);
          if (!s->inflate_buffer)
              return AVERROR(ENOMEM);
      }
  
      if (s->inflate_stream.avail_in == 0) {
          int read = http_buf_read(h, s->inflate_buffer, DECOMPRESS_BUF_SIZE);
          if (read <= 0)
              return read;
          s->inflate_stream.next_in  = s->inflate_buffer;
          s->inflate_stream.avail_in = read;
      }
  
      s->inflate_stream.avail_out = size;
      s->inflate_stream.next_out  = buf;
  
      ret = inflate(&s->inflate_stream, Z_SYNC_FLUSH);
      if (ret != Z_OK && ret != Z_STREAM_END)
          av_log(h, AV_LOG_WARNING, "inflate return value: %d, %s\n",
                 ret, s->inflate_stream.msg);
  
      return size - s->inflate_stream.avail_out;
  }
  #endif /* CONFIG_ZLIB */
  
  static int64_t http_seek_internal(URLContext *h, int64_t off, int whence, int force_reconnect);
  
  static int http_read_stream(URLContext *h, uint8_t *buf, int size)
  {
      HTTPContext *s = h->priv_data;
      int err, new_location, read_ret;
      int64_t seek_ret;
  
      if (!s->hd)
          return AVERROR_EOF;
  
      if (s->end_chunked_post && !s->end_header) {
          err = http_read_header(h, &new_location);
          if (err < 0)
              return err;
      }
  
  #if CONFIG_ZLIB
      if (s->compressed)
          return http_buf_read_compressed(h, buf, size);
  #endif /* CONFIG_ZLIB */
      read_ret = http_buf_read(h, buf, size);
      if (   (read_ret  < 0 && s->reconnect        && (!h->is_streamed || s->reconnect_streamed) && s->filesize > 0 && s->off < s->filesize)
          || (read_ret == 0 && s->reconnect_at_eof && (!h->is_streamed || s->reconnect_streamed))) {
          uint64_t target = h->is_streamed ? 0 : s->off;
  
          if (s->reconnect_delay > s->reconnect_delay_max)
              return AVERROR(EIO);
  
          av_log(h, AV_LOG_INFO, "Will reconnect at %"PRIu64" error=%s.\n", s->off, av_err2str(read_ret));
          av_usleep(1000U*1000*s->reconnect_delay);
          s->reconnect_delay = 1 + 2*s->reconnect_delay;
          seek_ret = http_seek_internal(h, target, SEEK_SET, 1);
          if (seek_ret != target) {
              av_log(h, AV_LOG_ERROR, "Failed to reconnect at %"PRIu64".\n", target);
              return read_ret;
          }
  
          read_ret = http_buf_read(h, buf, size);
      } else
          s->reconnect_delay = 0;
  
      return read_ret;
  }
  
  // Like http_read_stream(), but no short reads.
  // Assumes partial reads are an error.
  static int http_read_stream_all(URLContext *h, uint8_t *buf, int size)
  {
      int pos = 0;
      while (pos < size) {
          int len = http_read_stream(h, buf + pos, size - pos);
          if (len < 0)
              return len;
          pos += len;
      }
      return pos;
  }
  
  static void update_metadata(HTTPContext *s, char *data)
  {
      char *key;
      char *val;
      char *end;
      char *next = data;
  
      while (*next) {
          key = next;
          val = strstr(key, "='");
          if (!val)
              break;
          end = strstr(val, "';");
          if (!end)
              break;
  
          *val = '\0';
          *end = '\0';
          val += 2;
  
          av_dict_set(&s->metadata, key, val, 0);
  
          next = end + 2;
      }
  }
  
  static int store_icy(URLContext *h, int size)
  {
      HTTPContext *s = h->priv_data;
      /* until next metadata packet */
      uint64_t remaining;
  
      if (s->icy_metaint < s->icy_data_read)
          return AVERROR_INVALIDDATA;
      remaining = s->icy_metaint - s->icy_data_read;
  
      if (!remaining) {
          /* The metadata packet is variable sized. It has a 1 byte header
           * which sets the length of the packet (divided by 16). If it's 0,
           * the metadata doesn't change. After the packet, icy_metaint bytes
           * of normal data follows. */
          uint8_t ch;
          int len = http_read_stream_all(h, &ch, 1);
          if (len < 0)
              return len;
          if (ch > 0) {
              char data[255 * 16 + 1];
              int ret;
              len = ch * 16;
              ret = http_read_stream_all(h, data, len);
              if (ret < 0)
                  return ret;
              data[len + 1] = 0;
              if ((ret = av_opt_set(s, "icy_metadata_packet", data, 0)) < 0)
                  return ret;
              update_metadata(s, data);
          }
          s->icy_data_read = 0;
          remaining        = s->icy_metaint;
      }
  
      return FFMIN(size, remaining);
  }
  
  static int http_read(URLContext *h, uint8_t *buf, int size)
  {
      HTTPContext *s = h->priv_data;
  
      if (s->icy_metaint > 0) {
          size = store_icy(h, size);
          if (size < 0)
              return size;
      }
  
      size = http_read_stream(h, buf, size);
      if (size > 0)
          s->icy_data_read += size;
      return size;
  }
  
  /* used only when posting data */
  static int http_write(URLContext *h, const uint8_t *buf, int size)
  {
      char temp[11] = "";  /* 32-bit hex + CRLF + nul */
      int ret;
      char crlf[] = "\r\n";
      HTTPContext *s = h->priv_data;
  
      if (!s->chunked_post) {
          /* non-chunked data is sent without any special encoding */
          return ffurl_write(s->hd, buf, size);
      }
  
      /* silently ignore zero-size data since chunk encoding that would
       * signal EOF */
      if (size > 0) {
          /* upload data using chunked encoding */
          snprintf(temp, sizeof(temp), "%x\r\n", size);
  
          if ((ret = ffurl_write(s->hd, temp, strlen(temp))) < 0 ||
              (ret = ffurl_write(s->hd, buf, size)) < 0          ||
              (ret = ffurl_write(s->hd, crlf, sizeof(crlf) - 1)) < 0)
              return ret;
      }
      return size;
  }
  
  static int http_shutdown(URLContext *h, int flags)
  {
      int ret = 0;
      char footer[] = "0\r\n\r\n";
      HTTPContext *s = h->priv_data;
  
      /* signal end of chunked encoding if used */
      if (((flags & AVIO_FLAG_WRITE) && s->chunked_post) ||
          ((flags & AVIO_FLAG_READ) && s->chunked_post && s->listen)) {
          ret = ffurl_write(s->hd, footer, sizeof(footer) - 1);
          ret = ret > 0 ? 0 : ret;
          s->end_chunked_post = 1;
      }
  
      return ret;
  }
  
  static int http_close(URLContext *h)
  {
      int ret = 0;
      HTTPContext *s = h->priv_data;
  
  #if CONFIG_ZLIB
      inflateEnd(&s->inflate_stream);
      av_freep(&s->inflate_buffer);
  #endif /* CONFIG_ZLIB */
  
      if (!s->end_chunked_post)
          /* Close the write direction by sending the end of chunked encoding. */
          ret = http_shutdown(h, h->flags);
  
      if (s->hd)
          ffurl_closep(&s->hd);
      av_dict_free(&s->chained_options);
      return ret;
  }
  
  static int64_t http_seek_internal(URLContext *h, int64_t off, int whence, int force_reconnect)
  {
      HTTPContext *s = h->priv_data;
      URLContext *old_hd = s->hd;
      uint64_t old_off = s->off;
      uint8_t old_buf[BUFFER_SIZE];
      int old_buf_size, ret;
      AVDictionary *options = NULL;
  
      if (whence == AVSEEK_SIZE)
          return s->filesize;
      else if (!force_reconnect &&
               ((whence == SEEK_CUR && off == 0) ||
                (whence == SEEK_SET && off == s->off)))
          return s->off;
      else if ((s->filesize == UINT64_MAX && whence == SEEK_END))
          return AVERROR(ENOSYS);
  
      if (whence == SEEK_CUR)
          off += s->off;
      else if (whence == SEEK_END)
          off += s->filesize;
      else if (whence != SEEK_SET)
          return AVERROR(EINVAL);
      if (off < 0)
          return AVERROR(EINVAL);
      s->off = off;
  
      if (s->off && h->is_streamed)
          return AVERROR(ENOSYS);
  
      /* we save the old context in case the seek fails */
      old_buf_size = s->buf_end - s->buf_ptr;
      memcpy(old_buf, s->buf_ptr, old_buf_size);
      s->hd = NULL;
  
      /* if it fails, continue on old connection */
      if ((ret = http_open_cnx(h, &options)) < 0) {
          av_dict_free(&options);
          memcpy(s->buffer, old_buf, old_buf_size);
          s->buf_ptr = s->buffer;
          s->buf_end = s->buffer + old_buf_size;
          s->hd      = old_hd;
          s->off     = old_off;
          return ret;
      }
      av_dict_free(&options);
      ffurl_close(old_hd);
      return off;
  }
  
  static int64_t http_seek(URLContext *h, int64_t off, int whence)
  {
      return http_seek_internal(h, off, whence, 0);
  }
  
  static int http_get_file_handle(URLContext *h)
  {
      HTTPContext *s = h->priv_data;
      return ffurl_get_file_handle(s->hd);
  }
  
  static int http_get_short_seek(URLContext *h)
  {
      HTTPContext *s = h->priv_data;
      return ffurl_get_short_seek(s->hd);
  }
  
  #define HTTP_CLASS(flavor)                          \
  static const AVClass flavor ## _context_class = {   \
      .class_name = # flavor,                         \
      .item_name  = av_default_item_name,             \
      .option     = options,                          \
      .version    = LIBAVUTIL_VERSION_INT,            \
  }
  
  #if CONFIG_HTTP_PROTOCOL
  HTTP_CLASS(http);
  
  const URLProtocol ff_http_protocol = {
      .name                = "http",
      .url_open2           = http_open,
      .url_accept          = http_accept,
      .url_handshake       = http_handshake,
      .url_read            = http_read,
      .url_write           = http_write,
      .url_seek            = http_seek,
      .url_close           = http_close,
      .url_get_file_handle = http_get_file_handle,
      .url_get_short_seek  = http_get_short_seek,
      .url_shutdown        = http_shutdown,
      .priv_data_size      = sizeof(HTTPContext),
      .priv_data_class     = &http_context_class,
      .flags               = URL_PROTOCOL_FLAG_NETWORK,
      .default_whitelist   = "http,https,tls,rtp,tcp,udp,crypto,httpproxy"
  };
  #endif /* CONFIG_HTTP_PROTOCOL */
  
  #if CONFIG_HTTPS_PROTOCOL
  HTTP_CLASS(https);
  
  const URLProtocol ff_https_protocol = {
      .name                = "https",
      .url_open2           = http_open,
      .url_read            = http_read,
      .url_write           = http_write,
      .url_seek            = http_seek,
      .url_close           = http_close,
      .url_get_file_handle = http_get_file_handle,
      .url_get_short_seek  = http_get_short_seek,
      .url_shutdown        = http_shutdown,
      .priv_data_size      = sizeof(HTTPContext),
      .priv_data_class     = &https_context_class,
      .flags               = URL_PROTOCOL_FLAG_NETWORK,
      .default_whitelist   = "http,https,tls,rtp,tcp,udp,crypto,httpproxy"
  };
  #endif /* CONFIG_HTTPS_PROTOCOL */
  
  #if CONFIG_HTTPPROXY_PROTOCOL
  static int http_proxy_close(URLContext *h)
  {
      HTTPContext *s = h->priv_data;
      if (s->hd)
          ffurl_closep(&s->hd);
      return 0;
  }
  
  static int http_proxy_open(URLContext *h, const char *uri, int flags)
  {
      HTTPContext *s = h->priv_data;
      char hostname[1024], hoststr[1024];
      char auth[1024], pathbuf[1024], *path;
      char lower_url[100];
      int port, ret = 0, attempts = 0;
      HTTPAuthType cur_auth_type;
      char *authstr;
      int new_loc;
  
      if( s->seekable == 1 )
          h->is_streamed = 0;
      else
          h->is_streamed = 1;
  
      av_url_split(NULL, 0, auth, sizeof(auth), hostname, sizeof(hostname), &port,
                   pathbuf, sizeof(pathbuf), uri);
      ff_url_join(hoststr, sizeof(hoststr), NULL, NULL, hostname, port, NULL);
      path = pathbuf;
      if (*path == '/')
          path++;
  
      ff_url_join(lower_url, sizeof(lower_url), "tcp", NULL, hostname, port,
                  NULL);
  redo:
      ret = ffurl_open_whitelist(&s->hd, lower_url, AVIO_FLAG_READ_WRITE,
                                 &h->interrupt_callback, NULL,
                                 h->protocol_whitelist, h->protocol_blacklist, h);
      if (ret < 0)
          return ret;
  
      authstr = ff_http_auth_create_response(&s->proxy_auth_state, auth,
                                             path, "CONNECT");
      snprintf(s->buffer, sizeof(s->buffer),
               "CONNECT %s HTTP/1.1\r\n"
               "Host: %s\r\n"
               "Connection: close\r\n"
               "%s%s"
               "\r\n",
               path,
               hoststr,
               authstr ? "Proxy-" : "", authstr ? authstr : "");
      av_freep(&authstr);
  
      if ((ret = ffurl_write(s->hd, s->buffer, strlen(s->buffer))) < 0)
          goto fail;
  
      s->buf_ptr    = s->buffer;
      s->buf_end    = s->buffer;
      s->line_count = 0;
      s->filesize   = UINT64_MAX;
      cur_auth_type = s->proxy_auth_state.auth_type;
  
      /* Note: This uses buffering, potentially reading more than the
       * HTTP header. If tunneling a protocol where the server starts
       * the conversation, we might buffer part of that here, too.
       * Reading that requires using the proper ffurl_read() function
       * on this URLContext, not using the fd directly (as the tls
       * protocol does). This shouldn't be an issue for tls though,
       * since the client starts the conversation there, so there
       * is no extra data that we might buffer up here.
       */
      ret = http_read_header(h, &new_loc);
      if (ret < 0)
          goto fail;
  
      attempts++;
      if (s->http_code == 407 &&
          (cur_auth_type == HTTP_AUTH_NONE || s->proxy_auth_state.stale) &&
          s->proxy_auth_state.auth_type != HTTP_AUTH_NONE && attempts < 2) {
          ffurl_closep(&s->hd);
          goto redo;
      }
  
      if (s->http_code < 400)
          return 0;
      ret = ff_http_averror(s->http_code, AVERROR(EIO));
  
  fail:
      http_proxy_close(h);
      return ret;
  }
  
  static int http_proxy_write(URLContext *h, const uint8_t *buf, int size)
  {
      HTTPContext *s = h->priv_data;
      return ffurl_write(s->hd, buf, size);
  }
  
  const URLProtocol ff_httpproxy_protocol = {
      .name                = "httpproxy",
      .url_open            = http_proxy_open,
      .url_read            = http_buf_read,
      .url_write           = http_proxy_write,
      .url_close           = http_proxy_close,
      .url_get_file_handle = http_get_file_handle,
      .priv_data_size      = sizeof(HTTPContext),
      .flags               = URL_PROTOCOL_FLAG_NETWORK,
  };
  #endif /* CONFIG_HTTPPROXY_PROTOCOL */
  