mirror of
https://github.com/obgm/libcoap.git
synced 2026-11-10 19:00:40 +03:00
chrysn
6caf836023
the old implementation stuffed the pdu struct in front of the transport-level pbuf, and preserved it on the stack while the packages were sent. this had two advantages: * saving ram * preserving the other implementation's structure of pdu->hdr == pdu+1 (ie. starting right after the pdu struct) but two disadvantages: * bad readability and pointer juggling in the send routine * relying on the send function to block until the package is out (which works for simple implementations of lwip drivers but not dma etc) if something really assumes the contiguous memory structure, it will show (unfortunately by corrupting other pdu structs), and chances are people use ->hdr anyway.
97 lines
3.0 KiB
C
97 lines
3.0 KiB
C
/* mem.h -- CoAP memory handling
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*
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* Copyright (C) 2010,2011,2014 Olaf Bergmann <bergmann@tzi.org>
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*
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* This file is part of the CoAP library libcoap. Please see
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* README for terms of use.
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*/
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#ifndef _COAP_MEM_H_
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#define _COAP_MEM_H_
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#ifdef HAVE_STDLIB_H
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#include <stdlib.h>
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#endif
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#ifndef WITH_LWIP
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/**
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* Initializes libcoap's memory management. This function must be
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* called once before coap_malloc() can be used on constrained
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* devices.
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*/
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void coap_memory_init(void);
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#endif /* WITH_LWIP */
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/**
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* Type specifiers for coap_malloc_type(). Memory objects can be typed
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* to facilitate arrays of type objects to be used instead of dynamic
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* memory management on constrained devices.
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*/
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typedef enum {
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COAP_STRING, COAP_ATTRIBUTE_NAME, COAP_ATTRIBUTE_VALUE, COAP_NODE, COAP_CONTEXT, COAP_ENDPOINT, COAP_PDU
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} coap_memory_tag_t;
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#ifndef WITH_LWIP
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/**
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* Allocates a chunk of @p size bytes and returns a pointer to the
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* newly allocated memory. The @p type is used to select the
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* appropriate storage container on constrained devices. The storage
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* allocated by coap_malloc_type() must be released with
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* coap_free_type().
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*
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* @param type The type of object to be stored.
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* @param size The number of bytes requested.
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* @return A pointer to the allocated storage or @c NULL on error.
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*/
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void *coap_malloc_type(coap_memory_tag_t type, size_t size);
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/**
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* Releases the memory that was allocated by coap_malloc_type().
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* The type tag @p type must be the same that was used for
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* allocating the object pointed to by @p.
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*
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* @param type The type of the object to release.
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* @param p A pointer to memory that was allocated by
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* coap_malloc_type().
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*/
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void coap_free_type(coap_memory_tag_t type, void *p);
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/**
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* Wrapper function to coap_malloc_type() for backwards compatibility.
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*/
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static inline void *coap_malloc(size_t size) {
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return coap_malloc_type(COAP_STRING, size);
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}
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/**
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* Wrapper function to coap_free_type() for backwards compatibility.
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*/
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static inline void coap_free(void *object) {
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coap_free_type(COAP_STRING, object);
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}
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#endif /* not WITH_LWIP */
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#ifdef WITH_LWIP
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#include <lwip/memp.h>
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/* no initialization needed with lwip (or, more precisely: lwip must be
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* completely initialized anyway by the time coap gets active) */
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static inline void coap_memory_init(void) {}
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/* it would be nice to check that size equals the size given at the memp
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* declaration, but i currently don't see a standard way to check that without
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* sourcing the custom memp pools and becoming dependent of its syntax */
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#define coap_malloc_type(type, size) memp_malloc(MEMP_ ## type)
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#define coap_free_type(type, p) memp_free(MEMP_ ## type, p)
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/* those are just here to make uri.c happy where string allocation has not been made conditional */
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static inline void *coap_malloc(size_t size) { LWIP_ASSERT("coap_malloc must not be used in lwIP", 0); }
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static inline void coap_free(void *pointer) { LWIP_ASSERT("coap_free must not be used in lwIP", 0); }
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#endif /* WITH_LWIP */
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#endif /* _COAP_MEM_H_ */
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