SCP: Add Regex comparison condition to the IF command

README.md

@@ -109,6 +109,7 @@ Simulator binaries for x86 Linus, x86 macOS, and Windows for all recent changes
 - Almost all existing simulators have useful SET CONSOLE SPEED=nnn behaviors in both the bare console session as well as TELNET console sessions.
 - Simh global/startup configuration commands can be contained in the first of simh.ini found in: 1) The current working directory, 2) The User login directory, 3) The directory containing the simulator executable, 4) The ~/Library/Preferences directory, 5) The /Library/Preferences directory, or 6) The /etc directory.
 - Enhanced Ethernet functionality on macOS which leverages the OS provided vmnet capabilities.  This is available on all intel and Apple Silicon macOS systems starting with Catalina (10.15) which was released in 2019.
+- SCP IF command supports RegEx comparisons.
 
 #### All simulators build cleanly under OpenVMS on ia64 systems.
 

scp.c

@@ -2433,7 +2433,7 @@ static const char simh_help2[] =
       " command which returns the AFAIL condition, it will exit the running\n"
       " command file with the AFAIL status to the calling command file.  This\n"
       " behavior can be changed with the ON command as well as switches to the\n"
-      " invoking DO command.\n\n"
+      " invoking DO command.\n"
       "5Examples:\n"
       " A command file might be used to bootstrap an operating system that\n"
       " halts after the initial load from disk.  The ASSERT command is then\n"
@@ -2456,7 +2456,7 @@ static const char simh_help2[] =
       " In the example, if the A register is not 0, the \"ASSERT A=0\" command will\n"
       " be echoed, the command file will be aborted with an \"Assertion failed\"\n"
       " message.  Otherwise, the command file will continue to bring up the\n"
-      " operating system.\n"
+      " operating system.\n\n"
       "4IF-ELSE\n"
       " The IF command tests a simulator state condition and executes additional\n"
       " commands if the condition is true:\n\n"
@@ -2483,7 +2483,7 @@ static const char simh_help2[] =
       " Failure Code:\" command will be displayed, the contents of the A register\n"
       " will be displayed and the command file will be aborted with an \"Assertion\n"
       " failed\" message.  Otherwise, the command file will continue to bring up\n"
-      " the operating system.\n"
+      " the operating system.\n\n"
       "4Conditional Expressions\n"
       " The IF and ASSERT commands evaluate five different forms of conditional\n"
       " expressions.:\n\n"
@@ -2587,6 +2587,15 @@ static const char simh_help2[] =
       "++{NOT} DEVICE <device-name>\n\n"
       " Specifies a true (false {NOT}) condition if the device exists and is\n"
       " enabled.\n\n"
+      "5Regular Expressions Tests\n"
+      " Comparision using Regular Expressions are available when IF commands use\n"
+      " this form of a condition:\n\n"
+      "++{NOT} \"<string>\" =~ Regular-Expression\n\n"
+      " Specifies a true (false {NOT}) condition if the regular expression matches\n"
+      " the string.\n\n"
+      " When a regular expression match happens, the environment variable\n"
+      " _IF_RE_MATCH_GROUP_0 is set to the part of the string that matches the\n"
+      " specified regular expression.\n\n"
       "5Debugging Expression Evaluation\n"
       " Debug output can be produced which will walk through the details\n"
       " involved during expression evaluation.  This output can, for example,\n"
@@ -5405,10 +5414,73 @@ if (sim_switches & SWMASK ('F')) {      /* File Compare? */
         }
     return c1 - c2;
     }
+if (sim_switches & SWMASK ('R')) {      /* Regular Expression Compare? */
+    if (sim_pcre_regex_available) {
+        pcre *re;
+        int rc;
+        char *re_buf = NULL;
+        const char *errmsg;
+        int erroffset, re_nsub;
+        int *ovector = NULL;
+        static size_t sim_if_re_match_sub_count = 0;
+
+        re_buf = calloc (strlen (s2) + 1, 1);
+        if ((s2[0] == s2[strlen(s2)- 1]) && ((s2[0] == '\"') || (s2[0] == '\'')))
+            memcpy (re_buf, s2 + 1, strlen(s2)-2);       /* extract string without surrounding quotes */
+        else
+            strcpy (re_buf, s2);
+        re = pcre_compile ((char *)re_buf, (sim_switches & SWMASK ('I')) ? PCRE_CASELESS : 0, &errmsg, &erroffset, NULL);
+        (void)pcre_fullinfo (re, NULL, PCRE_INFO_CAPTURECOUNT, &re_nsub);
+        if (re == NULL) {
+            sim_messagef (SCPE_ARG, "Regular Expression Error: %s\n", errmsg);
+            free (re_buf);
+            return SCPE_ARG|SCPE_NOMESSAGE;
+            }
+        ovector = (int *)malloc (3 * (re_nsub + 1) * sizeof (*ovector));
+        if (sim_deb && (sim_scp_dev.dctrl & SIM_DBG_BRK_ACTION)) {
+            sim_debug (SIM_DBG_BRK_ACTION, &sim_scp_dev, "Checking String: %s\n", s1);
+            sim_debug (SIM_DBG_BRK_ACTION, &sim_scp_dev, "Against RegEx Match Rule: %s\n", re_buf);
+            }
+        rc = pcre_exec (re, NULL, s1, strlen (s1), 0, PCRE_NOTBOL, ovector, 3 * (re_nsub + 1));
+        free (re_buf);
+        pcre_free (re);
+        if (rc >= 0) {
+            size_t j;
+            char *buf = (char *)malloc (1 + strlen (s1));  /* largest buf needed is current string + NUL */
+
+            for (j=0; j < (size_t)rc; j++) {
+                char env_name[32];
+                int end_offs = ovector[2 * j + 1], start_offs = ovector[2 * j];
+
+                sprintf (env_name, "_IF_RE_MATCH_GROUP_%d", (int)j);
+                memcpy (buf, &s1[start_offs], end_offs - start_offs);
+                buf[end_offs - start_offs] = '\0';
+                setenv (env_name, buf, 1);      /* Make the match and substrings available as environment variables */
+                sim_debug (SIM_DBG_BRK_ACTION, &sim_scp_dev, "%s=%s\n", env_name, buf);
+                }
+            for (; j<sim_if_re_match_sub_count; j++) {
+                char env_name[32];
+
+                sprintf (env_name, "_IF_RE_MATCH_GROUP_%d", (int)j);
+                unsetenv (env_name);            /* Remove previous extra environment variables */
+                }
+            sim_if_re_match_sub_count = re_nsub;
+            free (buf);
+            }
+        free (ovector);
+        if (rc == PCRE_ERROR_NOMATCH)
+            return -1;
+        return 0;
+        }
+    else {
+        sim_printf ("RegEx support not available\n");
+        return -1;
+        }
+    }
 v1 = strtol(s1+1, &ep1, 0);
 v2 = strtol(s2+1, &ep2, 0);
-if ((ep1 != s1 + strlen (s1) - 1) ||
-    (ep2 != s2 + strlen (s2) - 1))
+if ((ep1 != s1 + strlen (s1) - 1) ||        /* s1 is numeric? */
+    (ep2 != s2 + strlen (s2) - 1))          
     return (strlen (s1) == strlen (s2)) ? strncmp (s1 + 1, s2 + 1, strlen (s1) - 2)
                                         : strcmp (s1, s2);
 if (v1 == v2)
@@ -5526,20 +5598,22 @@ if (Exist || (*gbuf == '"') || (*gbuf == '\'')) {       /* quoted string compari
         int aval;
         int bval;
         t_bool invert;
+        int32 plus_switches;
         } *optr, compare_ops[] =
         {
-            {"==",   0,  0, FALSE},
-            {"EQU",  0,  0, FALSE},
-            {"!=",   0,  0, TRUE},
-            {"NEQ",  0,  0, TRUE},
-            {"<",   -1, -1, FALSE},
-            {"LSS", -1, -1, FALSE},
-            {"<=",   0, -1, FALSE},
-            {"LEQ",  0, -1, FALSE},
-            {">",    1,  1, FALSE},
-            {"GTR",  1,  1, FALSE},
-            {">=",   0,  1, FALSE},
-            {"GEQ",  0,  1, FALSE},
+            {"==",   0,  0, FALSE,  0},
+            {"EQU",  0,  0, FALSE,  0},
+            {"!=",   0,  0, TRUE,   0},
+            {"NEQ",  0,  0, TRUE,   0},
+            {"<",   -1, -1, FALSE,  0},
+            {"LSS", -1, -1, FALSE,  0},
+            {"<=",   0, -1, FALSE,  0},
+            {"LEQ",  0, -1, FALSE,  0},
+            {">",    1,  1, FALSE,  0},
+            {"GTR",  1,  1, FALSE,  0},
+            {">=",   0,  1, FALSE,  0},
+            {"GEQ",  0,  1, FALSE,  0},
+            {"=~",   0,  1, FALSE,  SWMASK('R')},
             {NULL}};
 
     if (!*tptr)
@@ -5548,6 +5622,8 @@ if (Exist || (*gbuf == '"') || (*gbuf == '\'')) {       /* quoted string compari
     while (sim_isspace (*cptr))                         /* skip spaces */
         ++cptr;
     if (!Exist) {
+        int32 saved_switches;
+
         get_glyph (cptr, op, quote);
         for (optr = compare_ops; optr->op; optr++)
             if (0 == strncmp (op, optr->op, strlen (optr->op)))
@@ -5559,7 +5635,12 @@ if (Exist || (*gbuf == '"') || (*gbuf == '\'')) {       /* quoted string compari
             return sim_messagef (SCPE_ARG, "Invalid operator: %s\n", op);
         while (sim_isspace (*cptr))                     /* skip spaces */
             ++cptr;
+        sim_switches |= optr->plus_switches;
+        saved_switches = sim_switches;
+        if (sim_switches & SWMASK ('R'))                /* Regex operation? */
+            sim_switches &= ~SWMASK ('I');              /* Make sure to gather the regex literally */
         cptr = _get_string (cptr, gbuf2, 0);            /* get second string */
+        sim_switches = saved_switches;
         if (*cptr) {                                    /* more? */
             if (flag == 1)                              /* ASSERT has no more args */
                 return SCPE_2MARG;
@@ -7101,6 +7182,7 @@ if (1) {
     fprintf (st, "\n        %s", sim_si64);
     fprintf (st, "\n        %s", sim_sa64);
     fprintf (st, "\n        %s", eth_capabilities());
+    setenv ("SIM_ETHERNET_CAPABILITIES", eth_capabilities(), 1);
     idle_capable = sim_timer_idle_capable (&os_ms_sleep_1, &os_tick_size);
     fprintf (st, "\n        Idle/Throttling support is %savailable", idle_capable ? "" : "NOT ");
     if (sim_disk_vhd_support())
@@ -7173,9 +7255,9 @@ if (1) {
     fprintf (st, "\n        %s", sim_toffset_64 ? "Large File (>2GB) support" : "No Large File support");
     fprintf (st, "\n        SDL Video support: %s", vid_version());
     if (sim_pcre_regex_available)
-        fprintf (st, "\n        PCRE RegEx (Version %s) support for EXPECT commands", pcre_version());
+        fprintf (st, "\n        PCRE RegEx (Version %s) support for EXPECT and IF commands", pcre_version());
     else
-        fprintf (st, "\n        No RegEx support for EXPECT commands");
+        fprintf (st, "\n        No RegEx support for EXPECT or IF commands");
     fprintf (st, "\n        OS clock resolution: %dms", os_tick_size);
     fprintf (st, "\n        Time taken by msleep(1): %dms", os_ms_sleep_1);
     if (sim_editline_version != 0) {

sim_ether.c

@@ -1393,6 +1393,7 @@ static t_bool eth_vde_network_available = FALSE;
 const char *eth_capabilities(void)
  {
  static char capabilities[CBUFSIZE] = "";
+ char cap_env[CBUFSIZE];
 
  if (capabilities[0] != '\0')
      return capabilities;
@@ -1426,6 +1427,8 @@ const char *eth_capabilities(void)
  strlcat (capabilities, ":NAT", sizeof (capabilities));
 #endif
  strlcat (capabilities, ":UDP", sizeof (capabilities));
+ snprintf (cap_env, sizeof(cap_env), "SIM_ETHER_CAPABILITIES=%s", capabilities);
+ sim_set_environment (0, cap_env);
  return capabilities;
  }