SCP: Add the ability to Fprintf to memory buffer

scp.c

@@ -523,6 +523,7 @@ int32 sim_interval = 0;
 int32 sim_switches = 0;
 FILE *sim_ofile = NULL;
 TMLN *sim_oline = NULL;
+MEMFILE *sim_mfile = NULL;
 SCHTAB *sim_schrptr = FALSE;
 SCHTAB *sim_schaptr = FALSE;
 DEVICE *sim_dfdev = NULL;
@@ -4704,7 +4705,9 @@ t_stat show_queue (FILE *st, DEVICE *dnotused, UNIT *unotused, int32 flag, CONST
 DEVICE *dptr;
 UNIT *uptr;
 int32 accum;
+MEMFILE buf;
 
+memset (&buf, 0, sizeof (buf));
 if (cptr && (*cptr != 0))
     return SCPE_2MARG;
 if (sim_clock_queue == QUEUE_LIST_END)
@@ -4745,6 +4748,7 @@ else {
 sim_show_clock_queues (st, dnotused, unotused, flag, cptr);
 #if defined (SIM_ASYNCH_IO)
 pthread_mutex_lock (&sim_asynch_lock);
+sim_mfile = &buf;
 fprintf (st, "asynchronous pending event queue\n");
 if (sim_asynch_queue == QUEUE_LIST_END)
     fprintf (st, "  Empty\n");
@@ -4762,6 +4766,9 @@ else {
 fprintf (st, "asynch latency: %d nanoseconds\n", sim_asynch_latency);
 fprintf (st, "asynch instruction latency: %d instructions\n", sim_asynch_inst_latency);
 pthread_mutex_unlock (&sim_asynch_lock);
+sim_mfile = NULL;
+fprintf (st, "%*.*s", (int)buf.pos, (int)buf.pos, buf.buf);
+free (buf.buf);
 #endif /* SIM_ASYNCH_IO */
 return SCPE_OK;
 }
@@ -10931,12 +10938,61 @@ int Fprintf (FILE *f, const char* fmt, ...)
 int ret = 0;
 va_list args;
 
-va_start (args, fmt);
+if (sim_mfile) {
-if (sim_oline)
+    char stackbuf[STACKBUFSIZE];
-    tmxr_linemsgvf (sim_oline, fmt, args);
+    int32 bufsize = sizeof(stackbuf);
-else
+    char *buf = stackbuf;
-    ret = vfprintf (f, fmt, args);
+    va_list arglist;
-va_end (args);
+    int32 len;
+
+    buf[bufsize-1] = '\0';
+
+    while (1) {                                         /* format passed string, args */
+        va_start (arglist, fmt);
+#if defined(NO_vsnprintf)
+        len = vsprintf (buf, fmt, arglist);
+#else                                                   /* !defined(NO_vsnprintf) */
+        len = vsnprintf (buf, bufsize-1, fmt, arglist);
+#endif                                                  /* NO_vsnprintf */
+        va_end (arglist);
+
+/* If the formatted result didn't fit into the buffer, then grow the buffer and try again */
+
+        if ((len < 0) || (len >= bufsize-1)) {
+            if (buf != stackbuf)
+                free (buf);
+            bufsize = bufsize * 2;
+            if (bufsize < len + 2)
+                bufsize = len + 2;
+            buf = (char *) malloc (bufsize);
+            if (buf == NULL)                            /* out of memory */
+                return -1;
+            buf[bufsize-1] = '\0';
+            continue;
+            }
+        break;
+        }
+
+/* Store the formatted data */
+
+    if (sim_mfile->pos + len > sim_mfile->size) {
+        sim_mfile->size = sim_mfile->pos + 2 * MAX(bufsize, 512);
+        sim_mfile->buf = (char *)realloc (sim_mfile->buf, sim_mfile->size);
+        }
+    memcpy (sim_mfile->buf + sim_mfile->pos, buf, len);
+    sim_mfile->pos += len;
+
+    if (buf != stackbuf)
+        free (buf);
+    }
+else {
+    va_start (args, fmt);
+    if (sim_oline)
+        tmxr_linemsgvf (sim_oline, fmt, args);
+    else
+        ret = vfprintf (f, fmt, args);
+    va_end (args);
+    }
 return ret;
 }
 

sim_defs.h

@@ -428,6 +428,7 @@ typedef struct EXPECT EXPECT;
 typedef struct SEND SEND;
 typedef struct DEBTAB DEBTAB;
 typedef struct FILEREF FILEREF;
+typedef struct MEMFILE MEMFILE;
 typedef struct BITFIELD BITFIELD;
 
 typedef t_stat (*ACTIVATE_API)(UNIT *unit, int32 interval);
@@ -806,13 +807,18 @@ struct DEBTAB {
 #define SIM_DBG_ACTIVATE    0x20000
 #define SIM_DBG_AIO_QUEUE   0x40000
 
-/* File Reference */
+/* Open File Reference */
 struct FILEREF {
     char                name[CBUFSIZE];                 /* file name */
     FILE                *file;                          /* file handle */
     int32               refcount;                       /* reference count */
     };
 
+struct MEMFILE {
+    char                *buf;                           /* buffered data */
+    size_t              size;                        /* size */
+    size_t              pos;                         /* data used */
+    };
 /* 
    The following macros exist to help populate structure contents