On 2004-02-12T10:24:08+0100, Biot Olivier wrote:
> Wait a minute: this method should be made available to all dissectors!
Take it. It should be reasonable generic (but maybe needs another
name):
/*
* Uncompresses a zlib compressed packet inside a tvb
* tvb*: the tvb; not touched in any way
* offset: offset inside tvb
* comprlen: length of compressed data
* Returns a new uncompressed tvbuffer if uncompression succeeded
* or NULL if uncompression failed (or HAVE_LIBZ is not defined)
*/
tvbuff_t* uncompress_packet(tvbuff_t *tvb, int offset, int comprlen);
The only problems arise because there is no easy way to determine
the size of the uncompressed buffer. Currently the code takes a
(conservative?) guess that the uncompressed buffer is 9 times
larger than the compressed one. Uncompress failes if this guess
was wrong.
An alternative would be the use of inflate() and iterative memory
allocation.
Attached is a diff to make MSVC happier.
Kendy
--
Index: packet-slsk.c
===================================================================
RCS file: /cvsroot/ethereal/packet-slsk.c,v
retrieving revision 1.1
diff -u -r1.1 packet-slsk.c
--- packet-slsk.c 11 Feb 2004 20:23:19 -0000 1.1
+++ packet-slsk.c 12 Feb 2004 12:35:17 -0000
@@ -304,19 +304,34 @@
* or NULL if uncompression failed
*/
- char compr[comprlen];
int i = 0;
- long uncomprlen = (comprlen*10);
- char uncompr[uncomprlen];
int err = 0;
+ long uncomprlen = (comprlen*10);
+ guint8 * compr;
+ guint8 * uncompr;
tvbuff_t *uncompr_tvb;
+ compr = g_malloc(comprlen);
+ if (!compr){
+ return NULL;
+ }
+ uncompr = g_malloc(uncomprlen);
+ if (!uncompr){
+ g_free(compr);
+ return NULL;
+ }
+
while (i < comprlen) { compr[i] = tvb_get_guint8(tvb, offset+i); i++;}
err = uncompress((Bytef *)uncompr, &uncomprlen, (Bytef *)compr, comprlen);
- if (err != 0) return NULL;
+ g_free(compr);
+ if (err != 0) {
+ g_free(uncompr);
+ return NULL;
+ }
uncompr_tvb = tvb_new_real_data((guint8*) uncompr, uncomprlen, uncomprlen);
+ g_free(uncompr);
return uncompr_tvb;
}
#else
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