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108 lines
3.9 KiB
C
108 lines
3.9 KiB
C
/* The PyMem_ family: low-level memory allocation interfaces.
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See objimpl.h for the PyObject_ memory family.
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*/
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#ifndef Py_PYMEM_H
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#define Py_PYMEM_H
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#include "pyport.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* BEWARE:
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Each interface exports both functions and macros. Extension modules should
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use the functions, to ensure binary compatibility across Python versions.
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Because the Python implementation is free to change internal details, and
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the macros may (or may not) expose details for speed, if you do use the
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macros you must recompile your extensions with each Python release.
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Never mix calls to PyMem_ with calls to the platform malloc/realloc/
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calloc/free. For example, on Windows different DLLs may end up using
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different heaps, and if you use PyMem_Malloc you'll get the memory from the
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heap used by the Python DLL; it could be a disaster if you free()'ed that
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directly in your own extension. Using PyMem_Free instead ensures Python
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can return the memory to the proper heap. As another example, in
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PYMALLOC_DEBUG mode, Python wraps all calls to all PyMem_ and PyObject_
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memory functions in special debugging wrappers that add additional
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debugging info to dynamic memory blocks. The system routines have no idea
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what to do with that stuff, and the Python wrappers have no idea what to do
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with raw blocks obtained directly by the system routines then.
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*/
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/*
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* Raw memory interface
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* ====================
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*/
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/* Functions
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Functions supplying platform-independent semantics for malloc/realloc/
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free. These functions make sure that allocating 0 bytes returns a distinct
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non-NULL pointer (whenever possible -- if we're flat out of memory, NULL
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may be returned), even if the platform malloc and realloc don't.
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Returned pointers must be checked for NULL explicitly. No action is
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performed on failure (no exception is set, no warning is printed, etc).
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*/
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PyAPI_FUNC(void *) PyMem_Malloc(size_t);
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PyAPI_FUNC(void *) PyMem_Realloc(void *, size_t);
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PyAPI_FUNC(void) PyMem_Free(void *);
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/* Starting from Python 1.6, the wrappers Py_{Malloc,Realloc,Free} are
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no longer supported. They used to call PyErr_NoMemory() on failure. */
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/* Macros. */
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#ifdef PYMALLOC_DEBUG
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/* Redirect all memory operations to Python's debugging allocator. */
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#define PyMem_MALLOC PyObject_MALLOC
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#define PyMem_REALLOC PyObject_REALLOC
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#else /* ! PYMALLOC_DEBUG */
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/* PyMem_MALLOC(0) means malloc(1). Some systems would return NULL
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for malloc(0), which would be treated as an error. Some platforms
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would return a pointer with no memory behind it, which would break
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pymalloc. To solve these problems, allocate an extra byte. */
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#define PyMem_MALLOC(n) malloc((n) ? (n) : 1)
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#define PyMem_REALLOC(p, n) realloc((p), (n) ? (n) : 1)
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#endif /* PYMALLOC_DEBUG */
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/* In order to avoid breaking old code mixing PyObject_{New, NEW} with
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PyMem_{Del, DEL} and PyMem_{Free, FREE}, the PyMem "release memory"
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functions have to be redirected to the object deallocator. */
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#define PyMem_FREE PyObject_FREE
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/*
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* Type-oriented memory interface
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* ==============================
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*
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* These are carried along for historical reasons. There's rarely a good
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* reason to use them anymore (you can just as easily do the multiply and
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* cast yourself).
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*/
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#define PyMem_New(type, n) \
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( (type *) PyMem_Malloc((n) * sizeof(type)) )
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#define PyMem_NEW(type, n) \
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( (type *) PyMem_MALLOC((n) * sizeof(type)) )
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#define PyMem_Resize(p, type, n) \
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( (p) = (type *) PyMem_Realloc((p), (n) * sizeof(type)) )
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#define PyMem_RESIZE(p, type, n) \
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( (p) = (type *) PyMem_REALLOC((p), (n) * sizeof(type)) )
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/* In order to avoid breaking old code mixing PyObject_{New, NEW} with
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PyMem_{Del, DEL} and PyMem_{Free, FREE}, the PyMem "release memory"
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functions have to be redirected to the object deallocator. */
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#define PyMem_Del PyObject_Free
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#define PyMem_DEL PyObject_FREE
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#ifdef __cplusplus
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}
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#endif
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#endif /* !Py_PYMEM_H */
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