diff options
| author | Tim Peters <tim.peters@gmail.com> | 2001-11-18 04:06:29 (GMT) |
|---|---|---|
| committer | Tim Peters <tim.peters@gmail.com> | 2001-11-18 04:06:29 (GMT) |
| commit | 36515e28ed1c0b6170c4972761ca4a96d4af0075 (patch) | |
| tree | 713ff7b4d03e21394fd841082f6f13932a12322f | |
| parent | 8188e792d9778026eed09ab664ac4b16c8906034 (diff) | |
| download | cpython-36515e28ed1c0b6170c4972761ca4a96d4af0075.zip cpython-36515e28ed1c0b6170c4972761ca4a96d4af0075.tar.gz cpython-36515e28ed1c0b6170c4972761ca4a96d4af0075.tar.bz2 | |
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.
| -rw-r--r-- | Python/import.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/Python/import.c b/Python/import.c index 9f668bf..0b4cd0f 100644 --- a/Python/import.c +++ b/Python/import.c @@ -30,10 +30,22 @@ extern time_t PyOS_GetLastModificationTime(char *, FILE *); /* Change for each incompatible change */ /* 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 */ + 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 magic number: (YEAR-1995), MONTH, DAY */ +/* 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)) /* Magic word as global; note that _PyImport_Init() can change the @@ -63,7 +75,7 @@ static const struct filedescr _PyImport_StandardFiletab[] = { {".py", "r", PY_SOURCE}, #ifdef MS_WIN32 {".pyw", "r", PY_SOURCE}, -#endif +#endif {".pyc", "rb", PY_COMPILED}, {0, 0} }; @@ -739,7 +751,7 @@ load_source_module(char *name, char *pathname, FILE *fp) return NULL; } #endif - cpathname = make_compiled_pathname(pathname, buf, + cpathname = make_compiled_pathname(pathname, buf, (size_t)MAXPATHLEN + 1); if (cpathname != NULL && (fpc = check_compiled_module(pathname, mtime, cpathname))) { |