[gs-cvs] rev 7809 - in trunk/gs: doc src

[alexcher at ghostscript.com]

Author: alexcher
Date: 2007-03-28 17:53:36 -0700 (Wed, 28 Mar 2007)
New Revision: 7809

Modified:
   trunk/gs/doc/pscet_status.txt
   trunk/gs/src/zfileio.c
Log:
Don't store part of the state of readhexstring in not yet written bytes
of the target string to avoid the string modification when the operator
fails and the stack is restored. Fix CET 23-20-01.

DETAILS:
Pack the state into a single 32-bit word for the convenience of reusing
the procedures that take a single integer value as a state.

DIFFERENCE:
No other CET or Comparefiles differences.


Modified: trunk/gs/doc/pscet_status.txt
===================================================================
--- trunk/gs/doc/pscet_status.txt	2007-03-28 16:03:31 UTC (rev 7808)
+++ trunk/gs/doc/pscet_status.txt	2007-03-29 00:53:36 UTC (rev 7809)
@@ -4334,10 +4334,7 @@
 
 23-19-2  OK	
 
-23-20-1  DIFF	GS has different checksum. readhexstring uses the string to store
-		the state. Modified bytes print are not printable but affect the
-                checksum.
-              	Assign: Ray (low priority)
+23-20-1  OK	Fixed by rev. 7809. - Alex
 
 23-20-2  OK	
 

Modified: trunk/gs/src/zfileio.c
===================================================================
--- trunk/gs/src/zfileio.c	2007-03-28 16:03:31 UTC (rev 7808)
+++ trunk/gs/src/zfileio.c	2007-03-29 00:53:36 UTC (rev 7809)
@@ -118,17 +118,15 @@
 /* <file> <string> readhexstring <substring> <filled_bool> */
 private int zreadhexstring_continue(i_ctx_t *);
 
-/* We keep track of the odd digit in the next byte of the string */
-/* beyond the bytes already used.  (This is just for convenience; */
-/* we could do the same thing by passing 2 state parameters to the */
-/* continuation procedure instead of 1.) */
+/* We pack the odd digit above the the current position for the  */
+/* convenience of reusing procedures that take 1 state parameter */
 private int
-zreadhexstring_at(i_ctx_t *i_ctx_p, os_ptr op, uint start)
+zreadhexstring_at(i_ctx_t *i_ctx_p, os_ptr op, uint start, int odd)
 {
     stream *s;
     uint len, nread;
     byte *str;
-    int odd;
+    int odd_byte = odd;
     stream_cursor_write cw;
     int status;
 
@@ -136,16 +134,10 @@
     /*check_write_type(*op, t_string); *//* done by caller */
     str = op->value.bytes;
     len = r_size(op);
-    if (start < len) {
-	odd = str[start];
-	if (odd > 0xf)
-	    odd = -1;
-    } else
-	odd = -1;
     cw.ptr = str + start - 1;
     cw.limit = str + len - 1;
     for (;;) {
-	status = s_hex_process(&s->cursor.r, &cw, &odd,
+	status = s_hex_process(&s->cursor.r, &cw, &odd_byte,
 			       hex_ignore_garbage);
 	if (status == 1) {	/* filled the string */
 	    ref_assign_inline(op - 1, op);
@@ -161,9 +153,8 @@
     }
     nread = cw.ptr + 1 - str;
     if (status != EOFC) {	/* Error */
-	if (nread < len)
-	    str[nread] = (odd < 0 ? 0x10 : odd);
-	return handle_read_status(i_ctx_p, status, op - 1, &nread,
+	nread |= odd_byte << 24;
+        return handle_read_status(i_ctx_p, status, op - 1, &nread,
 				  zreadhexstring_continue);
     }
     /* Reached end-of-file before filling the string. */
@@ -179,23 +170,24 @@
     os_ptr op = osp;
 
     check_write_type(*op, t_string);
-    if (r_size(op) > 0)
-	*op->value.bytes = 0x10;
-    return zreadhexstring_at(i_ctx_p, op, 0);
+    return zreadhexstring_at(i_ctx_p, op, 0, -1);
 }
 /* Continue a readhexstring operation after a callout. */
-/* *op is the index within the string. */
+/* *op contains the index within the string and the odd flag. */
 private int
 zreadhexstring_continue(i_ctx_t *i_ctx_p)
 {
     os_ptr op = osp;
-    int code;
+    int code, length, odd;
 
     check_type(*op, t_integer);
-    if (op->value.intval < 0 || op->value.intval > r_size(op - 1))
+    length = op->value.intval & 0xFFFFFF;
+    odd = op->value.intval >> 24;
+    
+    if (length > r_size(op - 1) || odd < -1 || odd > 0xF)
 	return_error(e_rangecheck);
     check_write_type(op[-1], t_string);
-    code = zreadhexstring_at(i_ctx_p, op - 1, (uint) op->value.intval);
+    code = zreadhexstring_at(i_ctx_p, op - 1, (uint)length, odd);
     if (code >= 0)
 	pop(1);
     return code;