Revert changes relative to lib/*.[ch] recent renaming

This reverts renaming and usage of lib/*.h header files done
28-12-2012, reverting 2 commits:

  f871de0... build: make use of 76 lib/*.h renamed files
  ffd8e12... build: rename 76 lib/*.h files

This also reverts removal of redundant include guard (redundant thanks
to changes in above commits) done 2-12-2013, reverting 1 commit:

  c087374... curl_setup.h: remove redundant include guard

This also reverts renaming and usage of lib/*.c source files done
3-12-2013, reverting 3 commits:

  13606bb... build: make use of 93 lib/*.c renamed files
  5b6e792... build: rename 93 lib/*.c files
  7d83dff... build: commit 13606bbfde follow-up 1

Start of related discussion thread:

  http://curl.haxx.se/mail/lib-2013-01/0012.html

Asking for confirmation on pushing this revertion commit:

  http://curl.haxx.se/mail/lib-2013-01/0048.html

Confirmation summary:

  http://curl.haxx.se/mail/lib-2013-01/0079.html

NOTICE: The list of 2 files that have been modified by other
intermixed commits, while renamed, and also by at least one
of the 6 commits this one reverts follows below. These 2 files
will exhibit a hole in history unless git's '--follow' option
is used when viewing logs.

  lib/curl_imap.h
  lib/curl_smtp.h

1 files changed, 139 insertions, 0 deletions

diff --git a/lib/pingpong.h b/lib/pingpong.h
new file mode 100644
index 000000000..1d104cfbc
--- /dev/null
+++ b/lib/pingpong.h
@@ -0,0 +1,139 @@
+#ifndef HEADER_CURL_PINGPONG_H
+#define HEADER_CURL_PINGPONG_H
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2011, 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 http://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 "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;
+
+/*
+ * '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 timeval response; /* set to Curl_tvnow() 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);
+
+  int (*endofresp)(struct pingpong *pp, int *code);
+};
+
+/*
+ * Curl_pp_multi_statemach()
+ *
+ * called repeatedly until done when the multi interface is used.
+ */
+CURLcode Curl_pp_multi_statemach(struct pingpong *pp);
+
+/*
+ * Curl_pp_easy_statemach()
+ *
+ * called repeatedly until done when the easy interface is used.
+ */
+CURLcode Curl_pp_easy_statemach(struct pingpong *pp);
+
+
+/* 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 */
+long Curl_pp_state_timeout(struct pingpong *pp);
+
+
+/***********************************************************************
+ *
+ * Curl_pp_sendf()
+ *
+ * Send the formated 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 formated 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,
+                    int numsocks);
+
+#endif /* HEADER_CURL_PINGPONG_H */