From bug-octave-request at bevo dot che dot wisc dot edu Mon Dec 17 14:54:03 2001
Subject: Loading .mat file containing variable bound to empty string causes seg fault
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Douglas Eck <doug at idsia dot ch>
Cc: bug-octave at bevo dot che dot wisc dot edu, doug@ruchetta.idsia.ch
Date: Mon, 17 Dec 2001 14:53:21 -0600

On 17-Dec-2001, Douglas Eck <doug at idsia dot ch> wrote:

| To: bug-octave at bevo dot che dot wisc dot edu
| Cc: doug
| Subject: Loading .mat file containing variable bound to empty string causes seg fault
| 
| Bug report for Octave 2.1.35 configured for i386-pc-linux-gnu
| 
| Description:
| -----------
| 
| Loading a .mat file containing variable bound to an empty string causes 
| segmentation fault.
| This does not occur in 2.0.16
| 
| Repeat-By:
| ---------
| 
| Try this:
| 
| mystr="";
| save("foo.mat","mystr")
| load("foo.mat")

Please try the following patch.

Thanks,

jwe


2001-12-17  John W. Eaton  <jwe at bevo dot che dot wisc dot edu>

	* data-conv.cc (LS_DO_READ): Don't do anything unless len > 0.
	(LS_DO_WRITE): Likewise.
	

Index: data-conv.cc
===================================================================
RCS file: /usr/local/cvsroot/octave/liboctave/data-conv.cc,v
retrieving revision 1.13
diff -u -r1.13 data-conv.cc
--- data-conv.cc	1 Feb 2000 23:11:59 -0000	1.13
+++ data-conv.cc	17 Dec 2001 20:52:35 -0000
 at @ -188,14 +188,17 @@
 #define LS_DO_READ(TYPE, swap, data, size, len, stream) \
   do \
     { \
-      volatile TYPE *ptr = X_CAST (volatile TYPE *, data); \
-      stream.read (X_CAST (char *, ptr), size * len); \
-      if (swap) \
-        swap_ ## size ## _bytes (ptr, len); \
-      TYPE tmp = ptr[0]; \
-      for (int i = len - 1; i > 0; i--) \
-        data[i] = ptr[i]; \
-      data[0] = tmp; \
+      if (len > 0) \
+	{ \
+	  volatile TYPE *ptr = X_CAST (volatile TYPE *, data); \
+	  stream.read (X_CAST (char *, ptr), size * len); \
+	  if (swap) \
+	    swap_ ## size ## _bytes (ptr, len); \
+	  TYPE tmp = ptr[0]; \
+	  for (int i = len - 1; i > 0; i--) \
+	    data[i] = ptr[i]; \
+	  data[0] = tmp; \
+	} \
     } \
   while (0)
 
 at @ -205,13 +208,16 @@
 #define LS_DO_WRITE(TYPE, data, size, len, stream) \
   do \
     { \
-      char tmp_type = static_cast<char> (type); \
-      stream.write (&tmp_type, 1); \
-      TYPE *ptr = new TYPE [len]; \
-      for (int i = 0; i < len; i++) \
-        ptr[i] = X_CAST (TYPE, data[i]); \
-      stream.write (X_CAST (char *, ptr), size * len); \
-      delete [] ptr ; \
+      if (len > 0) \
+	{ \
+	  char tmp_type = static_cast<char> (type); \
+	  stream.write (&tmp_type, 1); \
+	  TYPE *ptr = new TYPE [len]; \
+	  for (int i = 0; i < len; i++) \
+	    ptr[i] = X_CAST (TYPE, data[i]); \
+	  stream.write (X_CAST (char *, ptr), size * len); \
+	  delete [] ptr ; \
+	} \
     } \
   while (0)
 



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