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msgb: introduce msgb_trim() and msgb_l3trim() to trim msgb's

This commit is contained in:
Harald Welte 2012-01-14 21:53:41 +01:00
parent 7be8c2b686
commit b0f91513cd
1 changed files with 28 additions and 0 deletions
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28
include/osmocom/core/msgb.h
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@ -312,6 +312,34 @@ static inline void msgb_reserve(struct msgb *msg, int len)
msg->tail += len;
}
/*! \brief Trim the msgb to a given absolute length
* \param[in] msg message buffer
* \param[in] len new total length of buffer
* \returns 0 in case of success, negative in case of error
*/
static inline int msgb_trim(struct msgb *msg, int len)
{
if (msg->len < len)
return -1;
msg->len -= len;
msg->tail -= len;
if (msg->tail < msg->data)
msg->tail = msg->data;
return 0;
}
/*! \brief Trim the msgb to a given layer3 length
* \pram[in] msg message buffer
* \param[in] l3len new layer3 length
* \returns 0 in case of success, negative in case of error
*/
static inline int msgb_l3trim(struct msgb *msg, int l3len)
{
return msgb_trim(msg, (msg->l3h - msg->data) + l3len);
}
/*! \brief Allocate message buffer with specified headroom
* \param[in] size size in bytes, including headroom
* \param[in] headroom headroom in bytes