Re: [Felix-impl] JudySL problem

[john s. <sk...@us...>]

On 30/10/2011, at 9:40 AM, john skaller wrote:

> Hi, I'm having some problems with JudySL .. not sure what's going on.


Well ... isn't this impossible?

// program
open Judy;
x := JSLArray();
var je: JError_t;
var pv : &word;
var buffer: &char = C_hack::cast[&char] (C_hack::malloc(1000));
for var i in 0 upto 1000 do
  var j = Cstdlib::rand();
println$ "Rand = " + str j;
var s = j.str;
println$ "Rand = " + s;
var cp = s.cstr;
println$ "C string="+ str cp;
  strncpy(buffer,cp,800);
print$ str i + " --> " + str j + " = " + buffer;
  JudySLIns(x,buffer,&je,&pv);
assert not (isNULL pv);
print$ " Done " + str i;
  if C_hack::cast[long] (*pv) != 0l do println "DUPLICATE"; done
  *pv = C_hack::cast[word] i;
  println$ " Assigned " + str i;
done


// tail of output
812 --> 1608776735 = 1608776735 Done 812 Assigned 812
Rand = 1891469415
Rand = 1891469415
C string=1891469415
813 --> 1891469415 = 1891469415 Done 813 Assigned 813
Rand = 726031364
Rand = 726031364
C string=726031364
814 --> 726031364 = 726031364 Done 814 Assigned 814
Rand = 407052494
Rand = 407052494
C string=407052494
815 --> 407052494 = 407052494 Done 815 Assigned 815
Rand = 1595850963
Rand = 1595850963
C string=1595850963
816 --> 1595850963 = 1595850963 Done 816 Assigned 816
Rand = 1543867758
Rand = 1543867758
C string=1543867758
817 --> 1543867758 = 1543867758 Done 817 Assigned 817
Rand = 1887985652
Rand = 1887985652
C string=1887985652
Segmentation fault
///

So .. strncpy has valid data but it is segfaulting.
The only way this could possibly happen is if the pointer variable buffer got corrupted.

--
john skaller
sk...@us...