mirror of https://github.com/python/cpython.git
113 lines
3.5 KiB
C
113 lines
3.5 KiB
C
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/* Lowest-level memory allocation interface */
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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
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should normally use the functions for ensuring binary compatibility
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of the user's code across Python versions. Subsequently, if the
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Python runtime switches to its own malloc (different from standard
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malloc), no recompilation is required for the extensions.
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The macro versions are free to trade compatibility for speed, although
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there's no guarantee they're ever faster. Extensions shouldn't use the
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macro versions, as they don't gurantee binary compatibility across
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releases.
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Do not mix calls to PyMem_xyz with calls to platform
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malloc/realloc/calloc/free. */
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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; useful if you need to be sure you're using the same memory
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allocator as Python (this can be especially important on Windows, if
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you need to make sure you're using the same MS malloc/free, and out of
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the same heap, as the main Python DLL uses).
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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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extern DL_IMPORT(void *) PyMem_Malloc(size_t);
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extern DL_IMPORT(void *) PyMem_Realloc(void *, size_t);
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extern DL_IMPORT(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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#ifndef PyMem_MALLOC
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#ifdef MALLOC_ZERO_RETURNS_NULL
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#define PyMem_MALLOC(n) malloc((n) ? (n) : 1)
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#else
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#define PyMem_MALLOC malloc
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#endif
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/* Caution: whether MALLOC_ZERO_RETURNS_NULL is #defined has nothing to
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do with whether platform realloc(non-NULL, 0) normally frees the memory
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or returns NULL. Rather than introduce yet another config variation,
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just make a realloc to 0 bytes act as if to 1 instead. */
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#define PyMem_REALLOC(p, n) realloc((p), (n) ? (n) : 1)
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#define PyMem_FREE free
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#endif /* PyMem_MALLOC */
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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.
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*/
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/* Functions */
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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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/* In order to avoid breaking old code mixing PyObject_{New, NEW} with
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PyMem_{Del, DEL} (there was no choice about this in 1.5.2), the latter
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have to be redirected to the object allocator. */
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/* XXX The parser module needs rework before this can be enabled. */
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#if 0
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#define PyMem_Del PyObject_Free
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#else
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#define PyMem_Del PyMem_Free
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#endif
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/* Macros */
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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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/* XXX The parser module needs rework before this can be enabled. */
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#if 0
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#define PyMem_DEL PyObject_FREE
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#else
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#define PyMem_DEL PyMem_FREE
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#endif
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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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