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Fixed pbuf_dechain() assertion. Removed old documentation from pbuf.h.

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likewise 2003-03-31 11:39:48 +00:00
parent 6c147709b6
commit a70f478ef1
2 changed files with 28 additions and 75 deletions
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34
src/core/pbuf.c
View File

@ -515,7 +515,7 @@ pbuf_header(struct pbuf *p, s16_t header_size)
(u8_t *)p->payload,
(u8_t *)p + sizeof(struct pbuf)) );\
/* restore old payload pointer */
p->payload = payload;/
p->payload = payload;
/* bail out unsuccesfully */
return 1;
}
@ -681,7 +681,10 @@ pbuf_ref_chain(struct pbuf *p)
/**
*
* Link two pbuf (chains) together.
* Link two pbufs (or chains) together.
*
* @param h head pbuf (chain)
* @param t tail pbuf (chain)
*
* The ->tot_len field of the first pbuf (h) is adjusted.
*/
@ -695,7 +698,7 @@ pbuf_chain(struct pbuf *h, struct pbuf *t)
/* proceed to last pbuf of chain */
for (p = h; p->next != NULL; p = p->next) {
/* add total length of second chain to each total of first chain */
/* add total length of second chain to all totals of first chain */
p->tot_len += t->tot_len;
}
/* chain last pbuf of h chain (p) with first of tail (t) */
@ -716,24 +719,27 @@ struct pbuf *
pbuf_dechain(struct pbuf *p)
{
struct pbuf *q;
u8_t deallocated;
u8_t tail_gone = 1;
/* tail */
q = p->next;
/* pbuf has successor in chain? */
if (q != NULL) {
/* tot_len invariant: (p->tot_len == p->len + p->next->tot_len) */
LWIP_ASSERT("p->tot_len = p->len + q->tot_len", p->tot_len = p->len + q->tot_len);
/* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
LWIP_ASSERT("p->tot_len == p->len + q->tot_len", q->tot_len == p->tot_len - p->len);
/* enforce invariant if assertion is disabled */
q->tot_len = p->tot_len - p->len;
/* decouple pbuf from remainder */
p->next = NULL;
/* total length of pbuf p is its own length only */
p->tot_len = p->len;
/* q is no longer referenced by p, free it */
DEBUGF(PBUF_DEBUG | DBG_FRESH | 2, ("pbuf_dechain: unreferencing %p\n", (void *) q));
tail_gone = pbuf_free(q);
/* return remaining tail or NULL if deallocated */
}
/* decouple pbuf from remainder */
p->tot_len = p->len;
p->next = NULL;
/* q is no longer referenced by p, free */
deallocated = pbuf_free(q);
DEBUGF(PBUF_DEBUG | DBG_FRESH | 2, ("pbuf_dechain: unreferencing %p\n", (void *) q));
/* return remaining tail or NULL if deallocated */
return (deallocated > 0? NULL: q);
/* assert tot_len invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0) */
LWIP_ASSERT("p->tot_len == p->len", p->tot_len == p->len);
return (tail_gone > 0? NULL: q);
}
/**

69
src/include/lwip/pbuf.h
View File

@ -64,20 +64,23 @@ typedef enum {
struct pbuf {
struct pbuf *next;
/* Pointer to the actual data in the buffer. */
/** pointer to the actual data in the buffer. */
void *payload;
/* total length of this buffer and additionally chained buffers */
/* (p->tot_len = p->len + p->next->tot_len) */
/**
* total length of this buffer and all chained buffers.
* invariant: (p->tot_len == p->len + (p->next? p->next->tot_len: 0)
*/
u16_t tot_len;
/* Length of this buffer. */
/* length of this buffer */
u16_t len;
/* flags */
u16_t flags;
/** the reference count always equals the number of pointers
/**
* the reference count always equals the number of pointers
* that refer to this pbuf. This can be pointers from an application,
* the stack itself, or pbuf->next pointers from a chain.
*/
@ -92,71 +95,15 @@ struct pbuf {
parameter specifies the size of the data allocated to those. */
void pbuf_init(void);
/* pbuf_alloc():
Allocates a pbuf at protocol layer l. The actual memory allocated
for the pbuf is determined by the layer at which the pbuf is
allocated and the requested size (from the size parameter). The
flag parameter decides how and where the pbuf should be allocated
as follows:
* PBUF_RAM: buffer memory for pbuf is allocated as one large
chunk. This includesprotocol headers as well.
* RBUF_ROM: no buffer memory is allocated for the pbuf, even for
protocol headers. Additional headers must be
prepended by allocating another pbuf and chain in to
the front of the ROM pbuf.
* PBUF_POOL: the pbuf is allocated as a pbuf chain, with pbufs from
the pbuf pool that is allocated during pbuf_init(). */
struct pbuf *pbuf_alloc(pbuf_layer l, u16_t size, pbuf_flag flag);
/* pbuf_realloc():
Shrinks the pbuf to the size given by the size parameter.
*/
void pbuf_realloc(struct pbuf *p, u16_t size);
/* pbuf_header():
Tries to move the p->payload pointer header_size number of bytes
upward within the pbuf. The return value is non-zero if it
fails. If so, an additional pbuf should be allocated for the header
and it should be chained to the front. */
u8_t pbuf_header(struct pbuf *p, s16_t header_size);
/* pbuf_ref():
Increments the reference count of the pbuf p.
*/
void pbuf_ref(struct pbuf *p);
void pbuf_ref_chain(struct pbuf *p);
/* pbuf_free():
Decrements the reference count and deallocates the pbuf if the
reference count is zero. If the pbuf is a chain all pbufs in the
chain are deallocated. */
u8_t pbuf_free(struct pbuf *p);
/* pbuf_clen():
Returns the length of the pbuf chain. */
u8_t pbuf_clen(struct pbuf *p);
/* pbuf_chain():
Chains pbuf t on the end of pbuf h. Pbuf h will have it's tot_len
field adjusted accordingly. Pbuf t should no be used any more after
a call to this function, since pbuf t is now a part of pbuf h. */
void pbuf_chain(struct pbuf *h, struct pbuf *t);
/* pbuf_dechain():
Picks off the first pbuf from the pbuf chain p. Returns the tail of
the pbuf chain or NULL if the pbuf p was not chained. */
struct pbuf *pbuf_dechain(struct pbuf *p);
struct pbuf *pbuf_take(struct pbuf *f);