These routines allow C code to work with serialized objects using the same data format as the
marshal
module. There are functions to write data into the serialization format, and additional functions that can be used to read the data back. Files used to store marshalled data must be opened in binary mode.
Numeric values are stored with the least significant byte first.
The module supports two versions of the data format: version
0
is the historical version, version
1
(new in Python 2.4) shares interned strings in the file, and upon unmarshalling. Version 2 (new in Python 2.5) uses a binary format for floating point numbers.
Py_MARSHAL_VERSION
indicates the current file format (currently 2).
PyMarshal_WriteLongToFile
(
long
value
, FILE
*file
, int
version
)
¶
Marshal a
long
integer,
value
，到
file
. This will only write the least-significant 32 bits of
value
; regardless of the size of the native
long
类型。
2.4 版改变： version indicates the file format.
PyMarshal_WriteObjectToFile
(
PyObject
*value
, FILE
*file
, int
version
)
¶
Marshal a Python object, value ，到 file .
2.4 版改变： version indicates the file format.
PyMarshal_WriteObjectToString
(
PyObject
*value
, int
version
)
¶
Return a string object containing the marshalled representation of value .
2.4 版改变： version indicates the file format.
The following functions allow marshalled values to be read back in.
XXX What about error detection? It appears that reading past the end of the file will always result in a negative numeric value (where that’s relevant), but it’s not clear that negative values won’t be handled properly when there’s no error. What’s the right way to tell? Should only non-negative values be written using these routines?
PyMarshal_ReadLongFromFile
(
FILE
*file
)
¶
返回 C
long
from the data stream in a
FILE*
opened for reading. Only a 32-bit value can be read in using this function, regardless of the native size of
long
.
PyMarshal_ReadShortFromFile
(
FILE
*file
)
¶
返回 C
short
from the data stream in a
FILE*
opened for reading. Only a 16-bit value can be read in using this function, regardless of the native size of
short
.
PyMarshal_ReadObjectFromFile
(
FILE
*file
)
¶
Return a Python object from the data stream in a
FILE*
opened for reading. On error, sets the appropriate exception (
EOFError
or
TypeError
) and returns
NULL
.
PyMarshal_ReadLastObjectFromFile
(
FILE
*file
)
¶
Return a Python object from the data stream in a
FILE*
opened for reading. Unlike
PyMarshal_ReadObjectFromFile()
, this function assumes that no further objects will be read from the file, allowing it to aggressively load file data into memory so that the de-serialization can operate from data in memory rather than reading a byte at a time from the file. Only use these variant if you are certain that you won’t be reading anything else from the file. On error, sets the appropriate exception (
EOFError
or
TypeError
) and returns
NULL
.
PyMarshal_ReadObjectFromString
(
char
*string
, Py_ssize_t
len
)
¶
Return a Python object from the data stream in a character buffer containing
len
bytes pointed to by
string
. On error, sets the appropriate exception (
EOFError
or
TypeError
) and returns
NULL
.
Changed in version 2.5:
This function used an
int
type for
len
. This might require changes in your code for properly supporting 64-bit systems.