--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/curl/lib/pingpong.h	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,150 @@
+#ifndef HEADER_CURL_PINGPONG_H
+#define HEADER_CURL_PINGPONG_H
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+
+#include "curl_setup.h"
+
+#if !defined(CURL_DISABLE_IMAP) || !defined(CURL_DISABLE_FTP) || \
+  !defined(CURL_DISABLE_POP3) || !defined(CURL_DISABLE_SMTP)
+#define USE_PINGPONG
+#endif
+
+/* forward-declaration, this is defined in urldata.h */
+struct connectdata;
+
+typedef enum {
+  FTPTRANSFER_BODY, /* yes do transfer a body */
+  FTPTRANSFER_INFO, /* do still go through to get info/headers */
+  FTPTRANSFER_NONE, /* don't get anything and don't get info */
+  FTPTRANSFER_LAST  /* end of list marker, never used */
+} curl_pp_transfer;
+
+/*
+ * 'pingpong' is the generic struct used for protocols doing server<->client
+ * conversations in a back-and-forth style such as FTP, IMAP, POP3, SMTP etc.
+ *
+ * It holds response cache and non-blocking sending data.
+ */
+struct pingpong {
+  char *cache;     /* data cache between getresponse()-calls */
+  size_t cache_size;  /* size of cache in bytes */
+  size_t nread_resp;  /* number of bytes currently read of a server response */
+  char *linestart_resp; /* line start pointer for the server response
+                           reader function */
+  bool pending_resp;  /* set TRUE when a server response is pending or in
+                         progress, and is cleared once the last response is
+                         read */
+  char *sendthis; /* allocated pointer to a buffer that is to be sent to the
+                     server */
+  size_t sendleft; /* number of bytes left to send from the sendthis buffer */
+  size_t sendsize; /* total size of the sendthis buffer */
+  struct curltime response; /* set to Curl_now() when a command has been sent
+                               off, used to time-out response reading */
+  long response_time; /* When no timeout is given, this is the amount of
+                         milliseconds we await for a server response. */
+
+  struct connectdata *conn; /* points to the connectdata struct that this
+                               belongs to */
+
+  /* Function pointers the protocols MUST implement and provide for the
+     pingpong layer to function */
+
+  CURLcode (*statemach_act)(struct connectdata *conn);
+
+  bool (*endofresp)(struct connectdata *conn, char *ptr, size_t len,
+                    int *code);
+};
+
+/*
+ * Curl_pp_statemach()
+ *
+ * called repeatedly until done. Set 'wait' to make it wait a while on the
+ * socket if there's no traffic.
+ */
+CURLcode Curl_pp_statemach(struct pingpong *pp, bool block,
+                           bool disconnecting);
+
+/* initialize stuff to prepare for reading a fresh new response */
+void Curl_pp_init(struct pingpong *pp);
+
+/* Returns timeout in ms. 0 or negative number means the timeout has already
+   triggered */
+time_t Curl_pp_state_timeout(struct pingpong *pp, bool disconnecting);
+
+
+/***********************************************************************
+ *
+ * Curl_pp_sendf()
+ *
+ * Send the formatted string as a command to a pingpong server. Note that
+ * the string should not have any CRLF appended, as this function will
+ * append the necessary things itself.
+ *
+ * made to never block
+ */
+CURLcode Curl_pp_sendf(struct pingpong *pp,
+                       const char *fmt, ...);
+
+/***********************************************************************
+ *
+ * Curl_pp_vsendf()
+ *
+ * Send the formatted string as a command to a pingpong server. Note that
+ * the string should not have any CRLF appended, as this function will
+ * append the necessary things itself.
+ *
+ * made to never block
+ */
+CURLcode Curl_pp_vsendf(struct pingpong *pp,
+                        const char *fmt,
+                        va_list args);
+
+/*
+ * Curl_pp_readresp()
+ *
+ * Reads a piece of a server response.
+ */
+CURLcode Curl_pp_readresp(curl_socket_t sockfd,
+                          struct pingpong *pp,
+                          int *code, /* return the server code if done */
+                          size_t *size); /* size of the response */
+
+
+CURLcode Curl_pp_flushsend(struct pingpong *pp);
+
+/* call this when a pingpong connection is disconnected */
+CURLcode Curl_pp_disconnect(struct pingpong *pp);
+
+int Curl_pp_getsock(struct pingpong *pp, curl_socket_t *socks);
+
+
+/***********************************************************************
+ *
+ * Curl_pp_moredata()
+ *
+ * Returns whether there are still more data in the cache and so a call
+ * to Curl_pp_readresp() will not block.
+ */
+bool Curl_pp_moredata(struct pingpong *pp);
+
+#endif /* HEADER_CURL_PINGPONG_H */