From b7005824453583d1459b49c5a424b50e2ea9a2c8 Mon Sep 17 00:00:00 2001
From: Pavel Machek <pavel@ucw.cz>
Date: Mon, 8 Mar 1999 20:30:06 +0000
Subject: Filters are now a tiny bit stronger (if is actually working ;-)

---
 filter/f-util.c | 85 +++++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 67 insertions(+), 18 deletions(-)

(limited to 'filter/f-util.c')

diff --git a/filter/f-util.c b/filter/f-util.c
index 66bf5f1..ba74804 100644
--- a/filter/f-util.c
+++ b/filter/f-util.c
@@ -21,33 +21,73 @@
 #include "conf/conf.h"
 #include "filter/filter.h"
 
-struct f_instruction *last_func = NULL;
+struct f_inst *last_func = NULL;
 
-static void
-interpret(struct f_instruction *what)
+#define runtime die
+
+static struct f_val
+interpret(struct f_inst *what)
 {
   struct symbol *sym;
+  struct f_val v1, v2, res;
+
+  res.type = T_VOID;
   if (!what)
-    return;
+    return res;
+
   switch(what->code) {
   case ',':
     interpret(what->arg1);
     interpret(what->arg2);
     break;
+  case '+':
+    v1 = interpret(what->arg1);
+    v2 = interpret(what->arg2);
+    if (v1.type != v2.type)
+      runtime( "Can not operate with values of incompatible types" );
+
+    switch (res.type = v1.type) {
+    case T_VOID: runtime( "Can not operate with values of type void" );
+    case T_INT: res.val.i = v1.val.i + v2.val.i; break;
+    default: runtime( "Usage of unknown type" );
+    }
+    break;
   case '=':
+    v1 = interpret(what->arg2);
     sym = what->arg1;
-    sym->aux = (int) what->arg2;
+    switch (res.type = v1.type) {
+    case T_VOID: runtime( "Can not assign void values" );
+    case T_INT: 
+      if (sym->class != SYM_VARIABLE_INT)
+	runtime( "Variable of bad type" );
+      sym->aux = v1.val.i; 
+      break;
+    }
+    break;
+  case 'c':
+    res.type = T_INT;
+    res.val.i = (int) what->arg1;
+    break;
+  case 'i':
+    res.type = T_INT;
+    res.val.i = * ((int *) what->arg1);
     break;
   case 'p':
-    sym = what->arg1;
-    switch(sym->class) {
-    case SYM_VARIABLE_INT: 
-      printf( "Printing: %d\n", sym->aux );
-      break;
-    default:
-      printf( "Unknown type passed to print\n" );
-      break;
+    v1 = interpret(what->arg1);
+    printf( "Printing: " );
+    switch (v1.type) {
+    case T_VOID: printf( "(void)" ); break;
+    case T_INT: printf( "%d", v1.val.i ); break;
+    default: runtime( "Print of variable of unknown type" );
     }
+    printf( "\n" );
+    break;
+  case '?':
+    v1 = interpret(what->arg1);
+    if (v1.type != T_INT)
+      runtime( "If requires integer expression" );
+    if (v1.val.i)
+      res = interpret(what->arg2);
     break;
   case 'D':
     printf( "DEBUGGING PRINT\n" );
@@ -55,8 +95,17 @@ interpret(struct f_instruction *what)
   case '0':
     printf( "No operation\n" );
     break;
+  case 'd':
+    printf( "Puts: %s\n", what->arg1 );
+    break;
+  case '!':
+    die( "Filter asked me to die" );
+  default:
+    die( "Unknown insruction %d(%c)", what->code, what->code & 0xff);
   }
-  interpret(what->next);
+  if (what->next)
+    return interpret(what->next);
+  return res;
 }
 
 void
@@ -69,11 +118,11 @@ filters_postconfig(void)
   }
 } 
 
-struct f_instruction *
+struct f_inst *
 f_new_inst(void)
 {
-  struct f_instruction * ret;
-  ret = cfg_alloc(sizeof(struct f_instruction));
+  struct f_inst * ret;
+  ret = cfg_alloc(sizeof(struct f_inst));
   ret->code = 0;
   ret->arg1 = ret->arg2 = ret->next = NULL;
   return ret;
@@ -82,7 +131,7 @@ f_new_inst(void)
 int
 f_run(struct symbol *filter, struct rte *rtein, struct rte **rteout)
 {
-  struct f_instruction *inst;
+  struct f_inst *inst;
   debug( "Running filter `%s'...", filter->name );
 
   inst = filter->def;
-- 
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