[Python-checkins] CVS: python/dist/src/Modules structmodule.c,2.41,2.42

[Tim Peters]

Update of /cvsroot/python/python/dist/src/Modules
In directory usw-pr-cvs1:/tmp/cvs-serv2102/python/dist/src/Modules

Modified Files:
	structmodule.c 
Log Message:
Repair portability of sign extension when reading signed ints on boxes
where sizeof(long)==8.  This *was* broken on boxes where signed right
shifts didn't sign-extend, but not elsewhere.  Unfortunately, apart
from the Cray T3E I don't know of such a box, and Guido has so far
refused to buy me any Cray machines for home Python testing <wink>.

More immediately interesting would be if someone could please test
this on *any* sizeof(long)==8 box, to make sure I didn't break it.


Index: structmodule.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Modules/structmodule.c,v
retrieving revision 2.41
retrieving revision 2.42
diff -C2 -r2.41 -r2.42
*** structmodule.c	2000/09/26 05:46:01	2.41
--- structmodule.c	2001/04/08 23:39:38	2.42
***************
*** 654,662 ****
  		x = (x<<8) | (*p++ & 0xFF);
  	} while (--i > 0);
! 	i = 8*(sizeof(long) - f->size);
! 	if (i) {
! 		x <<= i;
! 		x >>= i;
! 	}
  	return PyInt_FromLong(x);
  }
--- 654,660 ----
  		x = (x<<8) | (*p++ & 0xFF);
  	} while (--i > 0);
! 	/* Extend the sign bit. */
! 	if (SIZEOF_LONG > f->size)
! 		x |= -(x & (1L << (8*f->size - 1)));
  	return PyInt_FromLong(x);
  }
***************
*** 768,776 ****
  		x = (x<<8) | (p[--i] & 0xFF);
  	} while (i > 0);
! 	i = 8*(sizeof(long) - f->size);
! 	if (i) {
! 		x <<= i;
! 		x >>= i;
! 	}
  	return PyInt_FromLong(x);
  }
--- 766,772 ----
  		x = (x<<8) | (p[--i] & 0xFF);
  	} while (i > 0);
! 	/* Extend the sign bit. */
! 	if (SIZEOF_LONG > f->size)
! 		x |= -(x & (1L << (8*f->size - 1)));
  	return PyInt_FromLong(x);
  }