/*****************************************************************************/
#ifdef COMMENTS_WITH_COMMENTS
/*
                                MemBufDemo.c

This script is intended to demonstrate the use of the MemBufLib..() functions,
as well as allowing a direct comparison of the throughputs of the mailbox
(default) and memory-buffer IPCs for script output.  Testing indicates transfer
bandwidth in excess of 2x of the standard mailbox IPC, along with notable
improvements in resource utilisation.  YMMV with platform, O/S version and
TCP/IP stack (i.e. as the relative bottlenecks shuffle about).

The memory-buffer IPC is intended for bulk data transfer from a script to the
server and then on to the client.  In this case, "bulk" means megabytes, tens
of megabytes, hundreds of megabytes, and so forth.  For kilobytes, tens,
hundreds of kilobytes the mailbox IPC is suitable for most applications.

To compare the throughputs of the actual IPC, it is best to eliminate as much
storage access as possible (often the slowest element in a VMS system).  This
script ganerates a block of data comprising a repeating byte value.  The value
is incremented with each block and ranges from 0x00 thru to 0xff before
repeating.  The memset() used to populate the block is very efficient.

It is recommended to use a command-line tool such as cURL or wget with output
directed to the NL: device.  Output can also be directed to storage for the
purposes of comparing the content of both IPCs while building confidence in the
memory-buffer IPC.  Adding "-v" to cURL or "--server-response" to wget to
observe the response header.

The behaviour of the script is controlled by keys in the query string.

  ?<transfer-Mbytes>+[b|m]+<MRS-kbytes>+<memory-buffer-size-Mbytes>

No query string the default behaviour is a 10MB transfer via mailbox IPC.

  $ curl -o nl: http://the.host/cgi-bin/membufdemo
  $ wget "-O" NL: http://the.host/cgi-bin/membufdemo

The first key can be an integer number of *megabytes* to transfer.  For 5MB and
100MB respectively:

  $ curl -o nl: http://the.host/cgi-bin/membufdemo?5
  $ curl -o nl: http://the.host/cgi-bin/membufdemo?100

The second key is a character indicating the IPC; 'm' for mailbox (default) and
'b' for (memory-)buffer.  The first and third examples are mailbox and the
second and fourth memory-buffer.

  $ curl -o nl: http://the.host/cgi-bin/membufdemo?5
  $ curl -o nl: http://the.host/cgi-bin/membufdemo?5+b
  $ curl -o nl: http://the.host/cgi-bin/membufdemo?250+m
  $ curl -o nl: http://the.host/cgi-bin/membufdemo?250+b

The third key is an integer number of bytes for the record size.  This is the
mailbox maximum record size (MRS) in kilobytes, and so is limited to the WASD
configuration for script SYS$OUTPUT size.  With memory-buffer it can be
specified as any size up to size of the memory-buffer itself.  The default is
the mailbox MRS size. The first example specifies a MRS of 32kB and the second
256kB.

  $ curl -o nl: http://the.host/cgi-bin/membufdemo?100+m+32
  $ curl -o nl: http://the.host/cgi-bin/membufdemo?100+b+256

The fourth key is an integer number of megabytes for the memory-buffer.  The
default is 1MB.  Any value may be provided here with the server memory-buffer
manager either providing that size of an error report back in the callout.  The
first examples request a 2MB memory-buffer and the second 5MB.

  $ curl -o nl: http://the.host/cgi-bin/membufdemo?100+b+256+2
  $ curl -o nl: http://the.host/cgi-bin/membufdemo?100+b+128+5

To compare the data provided by both environments direct output to files and
use the difference UTILITY.

  $ curl -o []TEST.DAT http://the.host/cgi-bin/membufdemo?50
  $ curl -o []TEST.DAT http://the.host/cgi-bin/membufdemo?50+b
  $ diff TEST.DAT

WATCH may be used to observe the behaviour and data, etc., but beware with such
large datasets many browsers cannot cope with the copious report output,
particularly with [x]network-octets item, and in the case of mailbox IPC, with
the [x]DCL item.  YMMV.


COMPARISON
----------
Actual data generated by this utility comparing standard mailbox IPC with
memory-buffer on a x86-64 VirtualBox hosted system across a 1Gbps LAN with cURL
at the command-line on a 6 CPU 32GB macOS 15.1.

From the WASD Server Statistics / Environment report:

  innotek GmbH VirtualBox "Intel(R) Core(TM) i7-9700 CPU @ 3.00GHz"
  with 3 CPUs and 7GB running VMS V9.2-2

X86VMS$ @kits:vups
innotek GmbH VirtualBox with 3 CPU and 7936MB running VMS V9.2-2
Approximate System VUPs Rating : 651.8 ( min: 648.6 max: 653.4 )

Apache (2.4.62) comparison uses port 7780 and a DCL wrapper procedure with the
WASD script executable.

  X86VMS$ type APACHE$COMMON:[CGI-BIN]membufdemo.com
  $ apache$dcl_env
  $ membufdemo == "$apache$root:[cgi-bin]membufdemo.exe"
  $ membufdemo

YMMV: in absolute terms but the relative performance should remain.

Note: the cURL download speeds are MEGA-BYTES-per-second.

% curl -o /dev/null "http://x86vms.lan/cgi-bin/membufdemo?1000"
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 1000M  100 1000M    0     0  39.7M      0  0:00:25  0:00:25 --:--:-- 50.7M
                                 ^^^^^
% curl -o /dev/null "http://x86vms.lan/cgi-bin/membufdemo?1000+b"
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 1000M  100 1000M    0     0  81.9M      0  0:00:12  0:00:12 --:--:-- 83.0M
                                 ^^^^^
With VMS Apache:

% curl -o /dev/null "http://x86vms.lan:7780/cgi-bin/membufdemo?1000"
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 1000M    0 1000M    0     0  18.2M      0 --:--:--  0:00:54 --:--:-- 18.5M
                                 ^^^^^
With TLS secured connection.

% curl -k -o /dev/null "https://x86vms.lan/cgi-bin/membufdemo?1000"
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 1000M  100 1000M    0     0  22.1M      0  0:00:45  0:00:45 --:--:-- 20.9M
                                 ^^^^^
% curl -k -o /dev/null "https://x86vms.lan/cgi-bin/membufdemo?1000+b"
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 1000M  100 1000M    0     0  18.3M      0  0:00:54  0:00:54 --:--:-- 19.3M
                                 ^^^^^
TLS with VMS Apache:

% curl -k -o /dev/null "https://x86vms.lan:7443/cgi-bin/membufdemo?1000"
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 1000M    0 1000M    0     0  14.0M      0 --:--:--  0:01:11 --:--:-- 13.9M
                                 ^^^^^
By way of comparison, the WASD /stream function shows the maximim bandwidth
attainable over the LAN.

% curl -o /dev/null "http://x86vms.lan/stream/text:1g"
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 1024M  100 1024M    0     0  82.8M      0  0:00:12  0:00:12 --:--:-- 86.9M
                                 ^^^^^
Eliminating the actual physical LAN by having cURL on the same x86 system shows
the further potential moving data on 10Gbps and greater bandwidth.

X86VMS$ curl -o NL: "http://x86vms.lan/cgi-bin/membufdemo?1000"
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 1000M  100 1000M    0     0  38.7M      0  0:00:25  0:00:25 --:--:-- 25.6M
                                 ^^^^^
X86VMS$ curl -o NL: "http://x86vms.lan/cgi-bin/membufdemo?1000+b"
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 1000M  100 1000M    0     0   137M      0  0:00:07  0:00:07 --:--:--  135M
                                  ^^^^
With cURL running on the same system as Apache:

X86VMS$ curl -o NL: "http://x86vms.lan:7780/cgi-bin/membufdemo?1000"
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 1000M    0 1000M    0     0  34.8M      0 --:--:--  0:00:28 --:--:-- 34.7M
                                 ^^^^^
Again, the WASD /stream function shows the maximim bandwidth attainable.

X86VMS$ curl -o NL: "http://x86vms.lan/stream/test:1g"
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 1024M  100 1024M    0     0   144M      0  0:00:07  0:00:07 --:--:--  142M
                                  ^^^^
It is obvious that memory-buffer provides significantly greater throughput than
mailbox (from the http:// test) and that with TLS network transport the
encryption becomes a significant overhead and choke-point.

POSTSCRIPT: The comparison also illustrates that the WASD environment can
deliver significant bandwidth through its script->server->network pathways.
On the demonstration class of system; ~40MBps with the default mailbox IPC and
~82MBps using the memory-buffer IPC, approximately 80% available LAN bandwidth.
The WASD bandwidth is more than competitive with VMS Apache at ~18MBps, even
when using vanilla mailbox IPC, but particularly when using the memory buffer.


LOGICAL NAMES
-------------
None.


BUILD DETAILS
-------------
See BUILD_MEMBUFDEMO.COM procedure.


COPYRIGHT
---------
Copyright (C) 2017-2024 Mark G.Daniel

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.


VERSION HISTORY
---------------
27-OCT-2024  MGD  v1.1.0, tweaks (and adapt for comparison with Apache)
12-OCT-2017  MGD  initial
*/
#endif /* COMMENTS_WITH_COMMENTS */
/*****************************************************************************/

#define SOFTWAREVN "1.1.0"
#define SOFTWARENM "MEMBUFDEMO"
#ifdef __ALPHA
   char SoftwareID [] = SOFTWARENM " AXP-" SOFTWAREVN;
#endif
#ifdef __ia64
   char SoftwareID [] = SOFTWARENM " IA64-" SOFTWAREVN;
#endif
#ifdef __x86_64
   char SoftwareID [] = SOFTWARENM " X86-" SOFTWAREVN;
#endif

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>

#include "membuflib.h"

void MemBufDemoAbort (int);

/*****************************************************************************/

main (int argc, char* argv[])

{
   int  bcnt, cnt, gwmrs, gsize, mbfs, mrs, retval, status, total, value;
   char  *bptr, *cptr, *gname, *mbptr, *qsptr, *sptr;

   /*********/
   /* begin */
   /*********/

   if (argc > 1)
      if (!strcasecmp (argv[1], "/version"))
      {
         printf ("%%%s-I-VERSION, %s (%s)\n", SOFTWARENM, SoftwareID,
                                              MemBufLibVersion());
         exit (1);
      }

   gsize = gwmrs = mrs = mbfs = total = 0;
   gname = mbptr = NULL;

   /* WASD variable providing mailbox capacity */
   if (!(cptr = getenv("WWW_GATEWAY_MRS")))
      if (!(cptr = getenv("GATEWAY_MRS")))
         cptr = "0";
   if (isdigit(*cptr)) gwmrs = mrs = atoi(cptr);

   if (!(qsptr = getenv ("WWW_QUERY_STRING")))
      if (!(qsptr = getenv ("QUERY_STRING")))
         qsptr = "0";

   /* first is the total transfer in megabytes */
   cptr = qsptr;
   if (isdigit(*cptr)) total = atoi(cptr);
   if (total <= 0) total = 100;
   total *= (1024 * 1024);

   /* second is using 'm' mailbox (default) or memory-'b'uffer */
   while (*cptr && *cptr != '+') cptr++;
   if (*cptr) cptr++; 
   if (*cptr == 'b') mbptr = "";

   /* third is size of MRS in bytes */
   while (*cptr && *cptr != '+') cptr++;
   if (*cptr) cptr++; 
   if (isdigit(*cptr)) mrs = atoi(cptr);
   if (gwmrs && mrs > gwmrs)
      mrs = gwmrs;
   else
   if (mrs <= 0)
      mrs = 8192;

   if (!(bptr = malloc(mrs))) exit (vaxc$errno);

   /* fourth is memory-buffer size is in *megabytes* */
   while (*cptr && *cptr != '+') cptr++;
   if (*cptr) cptr++; 
   mbfs = 0;
   if (isdigit(*cptr)) mbfs = atoi(cptr);

   if (mbptr)
   {
      if (!(cptr = getenv("WWW_SERVER_SOFTWARE")))
         if (!(cptr = getenv("SERVER_SOFTWARE")))
            cptr = "";
      if (strstr (cptr, "Apache")) MemBufDemoAbort (44);

      /* using memory buffer */
      status = MemBufLibBegin (mbfs, &gname, NULL, &gsize);
      if (!(status & 1)) MemBufDemoAbort (status); 
   }

   /*******************/
   /* response header */
   /*******************/

   if (!(stdout = freopen ("SYS$OUTPUT", "w", stdout, "ctx=bin")))
      exit (vaxc$errno);

   fprintf (stdout,
"Status: 200\r\n\
Content-Type: application/octet-stream\r\n\
Content-Length: %d\r\n\
Content-Encoding: none\r\n\
X-query: %s\n\
X-mrs: %d\r\n\
X-mbuf: %s %u\r\n\
\r\n",
           total, qsptr, mrs,
           gname ? gname : "NULL", gsize);
   fflush (stdout);

   /**************/
   /* write data */
   /**************/
 
   bcnt = value = 0;
   while (bcnt < total)
   {
      memset (bptr, (value++ & 0xff), mrs);
      if (((cnt = mrs) + bcnt) > total) cnt = total - bcnt;
      if (mbptr)
         retval = MemBufLibWrite (bptr, cnt);
      else
         retval = fwrite (bptr, cnt, 1, stdout);
      if (!retval) exit (44);
      bcnt += cnt;
   }

   /************/
   /* finalise */
   /************/

   if (mbptr) MemBufLibEnd ();
}

/*****************************************************************************/

void MemBufDemoAbort (int status)

{

   /*********/
   /* begin */
   /*********/

   fprintf (stdout,
"Status: 500\r\n\
Content-Type: text/plain\r\n\
\r\n\
Status: %%X%08.08X\n",
            status);

   exit (status);
}

/*****************************************************************************/