[Python-checkins] CVS: python/dist/src/Python import.c,2.191,2.192

[Tim Peters]

Update of /cvsroot/python/python/dist/src/Python
In directory usw-pr-cvs1:/tmp/cvs-serv21711/python/Python

Modified Files:
	import.c 
Log Message:
Since the MAGIC number scheme is going to break on January 1st, document
what it is more carefully and point out some of the subtleties.


Index: import.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Python/import.c,v
retrieving revision 2.191
retrieving revision 2.192
diff -C2 -d -r2.191 -r2.192
*** import.c	2001/10/30 13:08:39	2.191
--- import.c	2001/11/18 04:06:29	2.192
***************
*** 31,38 ****
  /* The value of CR and LF is incorporated so if you ever read or write
     a .pyc file in text mode the magic number will be wrong; also, the
!    Apple MPW compiler swaps their values, botching string constants */
  /* XXX Perhaps the magic number should be frozen and a version field
     added to the .pyc file header? */
! /* New way to come up with the magic number: (YEAR-1995), MONTH, DAY */
  #define MAGIC (60717 | ((long)'\r'<<16) | ((long)'\n'<<24))
  
--- 31,50 ----
  /* The value of CR and LF is incorporated so if you ever read or write
     a .pyc file in text mode the magic number will be wrong; also, the
!    Apple MPW compiler swaps their values, botching string constants.
!    XXX That probably isn't important anymore.
! */
  /* XXX Perhaps the magic number should be frozen and a version field
     added to the .pyc file header? */
! /* New way to come up with the low 16 bits of the magic number:
!       (YEAR-1995) * 10000 +  MONTH * 100 + DAY
!    where MONTH and DAY are 1-based.
!    XXX Whatever the "old way" may have been isn't documented.
!    XXX This scheme breaks in 2002, as (2002-1995)*10000 = 70000 doesn't
!        fit in 16 bits.
!    XXX Later, sometimes 1 gets added to MAGIC in order to record that
!        the Unicode -U option is in use.  IMO (Tim's), that's a Bad Idea
!        (quite apart from that the -U option doesn't work so isn't used
!        anyway).
! */
  #define MAGIC (60717 | ((long)'\r'<<16) | ((long)'\n'<<24))
  
***************
*** 64,68 ****
  #ifdef MS_WIN32
  	{".pyw", "r", PY_SOURCE},
! #endif	
  	{".pyc", "rb", PY_COMPILED},
  	{0, 0}
--- 76,80 ----
  #ifdef MS_WIN32
  	{".pyw", "r", PY_SOURCE},
! #endif
  	{".pyc", "rb", PY_COMPILED},
  	{0, 0}
***************
*** 740,744 ****
  	}
  #endif
! 	cpathname = make_compiled_pathname(pathname, buf, 
  					   (size_t)MAXPATHLEN + 1);
  	if (cpathname != NULL &&
--- 752,756 ----
  	}
  #endif
! 	cpathname = make_compiled_pathname(pathname, buf,
  					   (size_t)MAXPATHLEN + 1);
  	if (cpathname != NULL &&