Process expression strings with octal constants correctly (tgt-vvp)

tgt-vvp was taking strings and processing them as is, but the strings
could contain octal constants. These constants needed to be converted
to binary form before they could be turned into a bit pattern.

tgt-vvp/eval_expr.c

@@ -1544,6 +1544,37 @@ static struct vector_info draw_realnum_expr(ivl_expr_t exp, unsigned wid)
       return res;
 }
 
+static char *process_octal_codes(const char *in, unsigned width)
+{
+      unsigned idx = 0;
+      unsigned ridx = 0;
+      unsigned str_len = strlen(in);
+      char *out = (char *)malloc(str_len+1);
+
+        /* If we do not have any octal codes just return the input. */
+      if (width/8 == str_len) {
+	    strcpy(out, in);
+	    return out;
+      }
+
+      while (idx < str_len) {
+	      /* An octal constant always has three digits. */
+	    if (in[ridx] == '\\') {
+		  out[idx] = (in[ridx+1]-'0')*64 + (in[ridx+2]-'0')*8 +
+		            (in[ridx+3]-'0');
+		  idx += 1;
+		  ridx += 4;
+	    } else {
+		  out[idx] = in[ridx];
+		  idx += 1;
+		  ridx += 1;
+	    }
+      }
+      out[idx] = '\0';
+
+      return out;
+}
+
 /*
  * A string in an expression is made up by copying constant bits into
  * the allocated vector.
@@ -1551,7 +1582,7 @@ static struct vector_info draw_realnum_expr(ivl_expr_t exp, unsigned wid)
 static struct vector_info draw_string_expr(ivl_expr_t exp, unsigned wid)
 {
       struct vector_info res;
-      const char *p = ivl_expr_string(exp);
+      char *p, *fp;
       unsigned ewid, nwid;
       unsigned bit = 0, idx;
 
@@ -1561,6 +1592,11 @@ static struct vector_info draw_string_expr(ivl_expr_t exp, unsigned wid)
       if (ewid < nwid)
 	    nwid = ewid;
 
+        /* Our string may have embedded \xxx sequences so they need
+           to be removed before we proceed. Returns a new string. */
+      fp = process_octal_codes(ivl_expr_string(exp), ewid);
+      p = fp;
+
       p += (ewid / 8) - 1;
 
 	/* The string needs to be represented as an allocated
@@ -1591,6 +1627,7 @@ static struct vector_info draw_string_expr(ivl_expr_t exp, unsigned wid)
       if (res.base >= 8)
 	    save_expression_lookaside(res.base, exp, wid);
 
+      free(fp);
       return res;
 }
 
@@ -2284,7 +2321,3 @@ struct vector_info draw_eval_expr(ivl_expr_t exp, int stuff_ok_flag)
       return draw_eval_expr_wid(exp, ivl_expr_width(exp), stuff_ok_flag);
 }
 
-/*
- * $Log: eval_expr.c,v $
- */
-