[gs-cvs] rev 7829 - in trunk/gs: doc src

[alexcher at ghostscript.com]

Author: alexcher
Date: 2007-04-06 08:58:56 -0700 (Fri, 06 Apr 2007)
New Revision: 7829

Modified:
   trunk/gs/doc/pscet_status.txt
   trunk/gs/src/dstack.h
   trunk/gs/src/interp.c
   trunk/gs/src/zdict.c
Log:
Following Adobe implementation don't restore the operand of --begin--
when it overflows the dictionary stack. Fix CET 20-02-02.

DETAILS:
Implement the approach suggested by L. Peter Deutsch.

- Change the check_dstack macro in dstack.h so it works the same as
  check_estack in estack.h -- i.e., if the current dstack block is full,
  call ref_stack_extend and then only return an error if
  ref_stack_extend fails.
- Change the handling of e_dictstackoverflow in interp.c so it works
  the same as e_execstackoverflow -- i.e., it doesn't try to extend the
  stack.
- Change the implementation of zbegin in zdict.c to work like
  check_dstack. I.e., if the current dstack block is full, call
  ref_stack_extend; if ref_stack_extend returns e_dictstackoverflow, pop
  the operand from the ostack before returning the error code.

With this approach, the interpreter does not have to know anything about
special handling of dictstackoverflow, and the right thing happens in
the special case of the 'begin' operator.

DIFFERENCES:
No other CET or Comparefiles differences. 


Modified: trunk/gs/doc/pscet_status.txt
===================================================================
--- trunk/gs/doc/pscet_status.txt	2007-04-06 10:17:36 UTC (rev 7828)
+++ trunk/gs/doc/pscet_status.txt	2007-04-06 15:58:56 UTC (rev 7829)
@@ -3856,10 +3856,7 @@
 
 20-02-1  OK	Looks okay. -Tor
 
-20-02-2  DIFF   When --begin-- overflows dictionary stack it restores the argument
-		and places the content of the dictionary stack on the operand
-                stack. Adobe interpreters don't restore the argument.
-                assign Alex
+20-02-2  OK     Fixed by rev. 7829. - Alex
 
 20-02-3  OK	Color corrected by rev 7172.
 

Modified: trunk/gs/src/dstack.h
===================================================================
--- trunk/gs/src/dstack.h	2007-04-06 10:17:36 UTC (rev 7828)
+++ trunk/gs/src/dstack.h	2007-04-06 15:58:56 UTC (rev 7829)
@@ -46,7 +46,9 @@
 /* Macro to ensure enough room on the dictionary stack */
 #define check_dstack(n)\
   if ( dstop - dsp < (n) )\
-    { d_stack.requested = (n); return_error(e_dictstackoverflow); }
+    { int ds_code_ = ref_stack_extend(&d_stack, n);\
+      if ( ds_code_ < 0 ) return ds_code_;\
+    }
 
 /*
  * The dictionary stack is implemented as a linked list of blocks;

Modified: trunk/gs/src/interp.c
===================================================================
--- trunk/gs/src/interp.c	2007-04-06 10:17:36 UTC (rev 7828)
+++ trunk/gs/src/interp.c	2007-04-06 15:58:56 UTC (rev 7829)
@@ -539,12 +539,10 @@
     /* we might be able to recover by adding or removing a block. */
     switch (code) {
 	case e_dictstackoverflow:
-	    if (ref_stack_extend(&d_stack, d_stack.requested) >= 0) {
-		dict_set_top();
-		doref = *perror_object;
-		epref = &doref;
-		goto again;
-	    }
+	    /* We don't have to handle this specially: */
+	    /* The only places that could generate it */
+	    /* use check_dstack, which does a ref_stack_extend, */
+	    /* so if` we get this error, it's a real one. */
 	    if (osp >= ostop) {
 		if ((ccode = ref_stack_extend(&o_stack, 1)) < 0)
 		    return ccode;

Modified: trunk/gs/src/zdict.c
===================================================================
--- trunk/gs/src/zdict.c	2007-04-06 10:17:36 UTC (rev 7828)
+++ trunk/gs/src/zdict.c	2007-04-06 15:58:56 UTC (rev 7829)
@@ -59,8 +59,18 @@
 
     check_type(*op, t_dictionary);
     check_dict_read(*op);
-    if (dsp == dstop)
-	return_error(e_dictstackoverflow);
+    if ( dsp == dstop ) { 
+        int code = ref_stack_extend(&d_stack, 1);
+
+        if ( code < 0 ) {
+            if (code == e_dictstackoverflow) {
+                /* Adobe doesn't restore the operand that caused stack */
+                /* overflow. We do the same to match CET 20-02-02      */
+                pop(1);
+            }
+            return code;
+        }
+    }
     ++dsp;
     ref_assign(dsp, op);
     dict_set_top();