Add new routines:

	tvb_get_string() - takes a tvbuff, an offset, and a length as
	arguments, allocates a buffer big enough to hold a string with
	the specified number of bytes plus an added null terminator
	(i.e., length+1), copies the specified number of bytes from the
	tvbuff, at the specified offset, to that buffer and puts in a
	null terminator, and returns a pointer to that buffer (or throws
	an exception before allocating the buffer if that many bytes
	aren't available in the tvbuff);

	tvb_get_stringz() - takes a tvbuff, an offset, and a pointer to
	a "gint" as arguments, gets the size of the null-terminated
	string starting at the specified offset in the tvbuff (throwing
	an exception if the null terminator isn't found), allocates a
	buffer big enough to hold that string, copies the string to that
	buffer, and returns a pointer to that buffer and stores the
	length of the string (including the terminating null) in the
	variable pointed to by the "gint" pointer.

Replace many pieces of code allocating a buffer and copying a string
with calls to "tvb_get_string()" (for one thing, "tvb_get_string()"
doesn't require you to remember that the argument to
"tvb_get_nstringz0()" is the size of the buffer into which you're
copying the string, which might be the length of the string to be copied
*plus 1*).

Don't use fixed-length buffers for null-terminated strings (even if the
code that generates those packets has a #define to limit the length of
the string).  Use "tvb_get_stringz()", instead.

In some cases where a value is fetched but is only used to pass an
argument to a "proto_tree_add_XXX" routine, use "proto_tree_add_item()"
instead.


git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@7859 f5534014-38df-0310-8fa8-9805f1628bb7

1 files changed, 21 insertions, 1 deletions

diff --git a/epan/tvbuff.h b/epan/tvbuff.h
index 5a08bac7b5..6dd756a03c 100644
--- a/epan/tvbuff.h
+++ b/epan/tvbuff.h
@@ -9,7 +9,7 @@
  * 		the data of a backing tvbuff, or can be a composite of
  * 		other tvbuffs.
  *
- * $Id: tvbuff.h,v 1.32 2003/05/19 03:23:12 gerald Exp $
+ * $Id: tvbuff.h,v 1.33 2003/06/12 08:33:31 guy Exp $
  *
  * Copyright (c) 2000 by Gilbert Ramirez <gram@alumni.rice.edu>
  *
@@ -318,6 +318,26 @@ extern char *tvb_fake_unicode(tvbuff_t *tvb, int offset, int len,
  */
 extern guint8 * tvb_format_text(tvbuff_t *tvb, gint offset, gint size);
 
+/*
+ * Given a tvbuff, an offset, and a length, allocate a buffer big enough
+ * to hold a non-null-terminated string of that length at that offset,
+ * plus a trailing '\0', copy the string into it, and return a pointer
+ * to the string.
+ *
+ * Throws an exception if the tvbuff ends before the string does.
+ */
+extern guint8 *tvb_get_string(tvbuff_t *tvb, gint offset, gint length);
+
+/*
+ * Given a tvbuff and an offset, with the offset assumed to refer to
+ * a null-terminated string, find the length of that string (and throw
+ * an exception if the tvbuff ends before we find the null), allocate
+ * a buffer big enough to hold the string, copy the string into it,
+ * and return a pointer to the string.  Also return the length of the
+ * string (including the terminating null) through a pointer.
+ */
+extern guint8 *tvb_get_stringz(tvbuff_t *tvb, gint offset, gint *lengthp);
+
 /* Looks for a stringz (NUL-terminated string) in tvbuff and copies
  * no more than bufsize number of bytes, including terminating NUL, to buffer.
  * Returns length of string (not including terminating NUL), or -1 if the string was